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Sample records for freeze drying process

  1. CFD modelling of condensers for freeze-drying processes

    Indian Academy of Sciences (India)

    Miriam Petitti; Antonello A Barresi; Daniele L Marchisio

    2013-12-01

    The aim of the present research is the development of a computational tool for investigating condensation processes and equipment with particular attention to freeze-dryers. These condensers in fact are usually operated at very low pressures, making it difficult to experimentally acquire quantitative knowledge of all the variables involved. Mathematical modelling and CFD (Computational Fluid Dynamics) simulations are used here to achieve a better comprehension of the flow dynamics and of the process of ice condensation and deposition in the condenser, in order to evaluate condenser efficiency and gain deeper insights of the process to be used for the improvement of its design. Both a complete laboratory-scale freeze-drying apparatus and an industrial-scale condenser have been investigated in this work, modelling the process of water vapour deposition. Different operating conditions have been considered and the influence exerted by the inert gas as well as other parameters has been investigated.

  2. The effect of dryer load on freeze drying process design.

    Science.gov (United States)

    Patel, Sajal M; Jameel, Feroz; Pikal, Michael J

    2010-10-01

    Freeze-drying using a partial load is a common occurrence during the early manufacturing stages when insufficient amounts of active pharmaceutical ingredient (API) are available. In such cases, the immediate production needs are met by performing lyophilization with less than a full freeze dryer load. However, it is not obvious at what fractional load significant deviations from full load behavior begin. The objective of this research was to systematically study the effects of variation in product load on freeze drying behavior in laboratory, pilot and clinical scale freeze-dryers. Experiments were conducted with 5% mannitol (high heat and mass flux) and 5% sucrose (low heat and mass flux) at different product loads (100%, 50%, 10%, and 2%). Product temperature was measured in edge as well as center vials with thermocouples. Specific surface area (SSA) was measured by BET gas adsorption analysis and residual moisture was measured by Karl Fischer. In the lab scale freeze-dryer, the molar flux of inert gas was determined by direct flow measurement using a flowmeter and the molar flux of water vapor was determined by manometric temperature measurement (MTM) and tunable diode laser absorption spectroscopy (TDLAS) techniques. Comparative pressure measurement (capacitance manometer vs. Pirani) was used to determine primary drying time. For both 5% mannitol and 5% sucrose, primary drying time decreases and product temperature increases as the load on the shelves decreases. No systematic variation was observed in residual moisture and vapor composition as load decreased. Further, SSA data suggests that there are no significant freezing differences under different load conditions. Independent of dryer scale, among all the effects, variation in radiation heat transfer from the chamber walls to the product seems to be the dominant effect resulting in shorter primary drying time as the load on the shelf decreases (i.e., the fraction of edge vials increases).

  3. A Mathematical Model for Freeze-Drying

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the experiments on freeze-drying carrot and potato slabs, the effects of some parameters, such as heating temperature and pressure on the freeze-drying process are examined. A simple model of freeze-drying is established to predict drying time and the mass variations of materials during the drying. The experimental results agree well with those calculated by the model.

  4. Augmenting Lagoon Process Using Reactivated Freeze-dried Biogranules.

    Science.gov (United States)

    Pishgar, Roya; Hamza, Rania Ahmed; Tay, Joo Hwa

    2017-02-24

    This study investigated the feasibility of using freeze-dried biogranules in lagoon basins. The effect of different operational conditions on treatment performance and detention time of granule-based lagoons was examined in a series of laboratory-scale batch studies. Optimal granule dosage was 0.1 g/L under anaerobic condition, resulting in 80-94% removal of 1000 mg/L chemical oxygen demand (COD) in 7-10 days. Under aerobic condition, granule dosage of 0.2 g/L achieved the best result for identical COD concentration. However, adequate amount of nutrients (optimal COD/N/P ratio of 100/13/0.8) should be supplied to encourage the growth of aerobic species. At optimal COD/N/P ratio, aerobic treatment interval significantly reduced to 2-3 days with corresponding COD removal efficiency of 88-92%. Inhibition of high concentrations of COD (5000 mg/L) and ammonia (480 mg/L NH4-N) was observed on microbial activity and treatment capacity of the biogranules. Mixing was a crucial measure to overcome mass transfer limitation. Onetime inoculation of lagoon with fresh granules was the best approach to achieve a satisfactory treatment efficiency. This study suggested that utilization of the biogranules is a feasible and sustainable technique for augmenting lagoon plants in terms of improved effluent quality and reduced retention time. Graphical Abstract ᅟ.

  5. Infrared Thermography for Monitoring of Freeze-Drying Processes: Instrumental Developments and Preliminary Results

    Science.gov (United States)

    Emteborg, Håkan; Zeleny, Reinhard; Charoud-Got, Jean; Martos, Gustavo; Lüddeke, Jörg; Schellin, Holger; Teipel, Katharina

    2014-01-01

    Coupling an infrared (IR) camera to a freeze dryer for on-line monitoring of freeze-drying cycles is described for the first time. Normally, product temperature is measured using a few invasive Pt-100 probes, resulting in poor spatial resolution. To overcome this, an IR camera was placed on a process-scale freeze dryer. Imaging took place every 120 s through a Germanium window comprising 30,000 measurement points obtained contact-free from −40°C to 25°C. Results are presented for an empty system, bulk drying of cheese slurry, and drying of 1 mL human serum in 150 vials. During freezing of the empty system, differences of more than 5°C were measured on the shelf. Adding a tray to the empty system, a difference of more than 8°C was observed. These temperature differences probably cause different ice structures affecting the drying speed during sublimation. A temperature difference of maximum 13°C was observed in bulk mode during sublimation. When drying in vials, differences of more than 10°C were observed. Gradually, the large temperature differences disappeared during secondary drying and products were transformed into uniformly dry cakes. The experimental data show that the IR camera is a highly versatile on-line monitoring tool for different kinds of freeze-drying processes. © 2014 European Union 103:2088–2097, 2014 PMID:24902839

  6. Effects of Freeze-Dried Vegetable Products on the Technological Process and the Quality of Dry Fermented Sausages.

    Science.gov (United States)

    Eisinaite, Viktorija; Vinauskiene, Rimante; Viskelis, Pranas; Leskauskaite, Daiva

    2016-09-01

    The aim of this study was to compare the chemical composition of freeze-dried vegetable powders: celery, celery juice, parsnip and leek. The effect of different freeze-dried vegetables onto the ripening process and the properties of dry fermented sausages was also evaluated. Vegetable products significantly (p fermentation and ripening process of dry fermented sausages. In addition, the color parameters for sausages with the added lyophilised celery products were considerable (p sausages made with lyophilised celery juice were characterised by higher lightness and lower hardness than those made with the addition of other vegetable products and control. Freeze-dried celery, celery juice, parsnip and leek have some potential for the usage as a functional ingredient or as a source for indirect addition of nitrate in the production of fermented sausages.

  7. The influence of lysozyme on mannitol polymorphism in freeze-dried and spray-dried formulations depends on the selection of the drying process

    DEFF Research Database (Denmark)

    Grohganz, Holger; Lee, Yan-Ying; Rantanen, Jukka

    2013-01-01

    -infrared spectroscopy in combination with multivariate analysis and further, results were verified with X-ray powder diffraction. It was seen that the prevalence of the mannitol polymorphic form shifted from ß-mannitol to d-mannitol with increasing protein concentration in freeze-dried formulations. In spray......-dried formulations an increase in protein concentration resulted in a shift from ß-mannitol to a-mannitol. An increase in final drying temperature of the freeze-drying process towards the temperature of the spray-drying process did not lead to significant changes. It can thus be concluded that it is the drying...

  8. The influence of lysozyme on mannitol polymorphism in freeze-dried and spray-dried formulations depends on the selection of the drying process.

    Science.gov (United States)

    Grohganz, Holger; Lee, Yan-Ying; Rantanen, Jukka; Yang, Mingshi

    2013-04-15

    Freeze-drying and spray-drying are often applied drying techniques for biopharmaceutical formulations. The formation of different solid forms upon drying is often dependent on the complex interplay between excipient selection and process parameters. The purpose of this study was to investigate the influence of the chosen drying method on the solid state form. Mannitol-lysozyme solutions of 20mg/mL, with the amount of lysozyme varying between 2.5% and 50% (w/w) of total solid content, were freeze-dried and spray-dried, respectively. The resulting solid state of mannitol was analysed by near-infrared spectroscopy in combination with multivariate analysis and further, results were verified with X-ray powder diffraction. It was seen that the prevalence of the mannitol polymorphic form shifted from β-mannitol to δ-mannitol with increasing protein concentration in freeze-dried formulations. In spray-dried formulations an increase in protein concentration resulted in a shift from β-mannitol to α-mannitol. An increase in final drying temperature of the freeze-drying process towards the temperature of the spray-drying process did not lead to significant changes. It can thus be concluded that it is the drying process in itself, rather than the temperature, that leads to the observed solid state changes.

  9. Mechanistic modelling of infrared mediated energy transfer during the primary drying step of a continuous freeze-drying process.

    Science.gov (United States)

    Van Bockstal, Pieter-Jan; Mortier, Séverine Thérèse F C; De Meyer, Laurens; Corver, Jos; Vervaet, Chris; Nopens, Ingmar; De Beer, Thomas

    2017-01-12

    Conventional pharmaceutical freeze-drying is an inefficient and expensive batch-wise process, associated with several disadvantages leading to an uncontrolled end product variability. The proposed continuous alternative, based on spinning the vials during freezing and on optimal energy supply during drying, strongly increases process efficiency and improves product quality (uniformity). The heat transfer during continuous drying of the spin frozen vials is provided via non-contact infrared (IR) radiation. The energy transfer to the spin frozen vials should be optimised to maximise the drying efficiency while avoiding cake collapse. Therefore, a mechanistic model was developed which allows computing the optimal, dynamic IR heater temperature in function of the primary drying progress and which, hence, also allows predicting the primary drying endpoint based on the applied dynamic IR heater temperature. The model was validated by drying spin frozen vials containing the model formulation (3.9mL in 10R vials) according to the computed IR heater temperature profile. In total, 6 validation experiments were conducted. The primary drying endpoint was experimentally determined via in-line near-infrared (NIR) spectroscopy and compared with the endpoint predicted by the model (50min). The mean ratio of the experimental drying time to the predicted value was 0.91, indicating a good agreement between the model predictions and the experimental data. The end product had an elegant product appearance (visual inspection) and an acceptable residual moisture content (Karl Fischer).

  10. Fundamentals of freeze-drying.

    Science.gov (United States)

    Nail, Steven L; Jiang, Shan; Chongprasert, Suchart; Knopp, Shawn A

    2002-01-01

    Given the increasing importance of reducing development time for new pharmaceutical products, formulation and process development scientists must continually look for ways to "work smarter, not harder." Within the product development arena, this means reducing the amount of trial and error empiricism in arriving at a formulation and identification of processing conditions which will result in a quality final dosage form. Characterization of the freezing behavior of the intended formulation is necessary for developing processing conditions which will result in the shortest drying time while maintaining all critical quality attributes of the freeze-dried product. Analysis of frozen systems was discussed in detail, particularly with respect to the glass transition as the physical event underlying collapse during freeze-drying, eutectic mixture formation, and crystallization events upon warming of frozen systems. Experiments to determine how freezing and freeze-drying behavior is affected by changes in the composition of the formulation are often useful in establishing the "robustness" of a formulation. It is not uncommon for seemingly subtle changes in composition of the formulation, such as a change in formulation pH, buffer salt, drug concentration, or an additional excipient, to result in striking differences in freezing and freeze-drying behavior. With regard to selecting a formulation, it is wise to keep the formulation as simple as possible. If a buffer is needed, a minimum concentration should be used. The same principle applies to added salts: If used at all, the concentration should be kept to a minimum. For many proteins a combination of an amorphous excipient, such as a disaccharide, and a crystallizing excipient, such as glycine, will result in a suitable combination of chemical stability and physical stability of the freeze-dried solid. Concepts of heat and mass transfer are valuable in rational design of processing conditions. Heat transfer by conduction

  11. Impregnation of leather during "freeze-drying"

    DEFF Research Database (Denmark)

    Storch, Mikkel; Vestergaard Poulsen Sommer, Dorte; Hovmand, Ida

    2016-01-01

    Freeze-drying is a recognized method for the preservation of waterlogged objects. Naturally, freeze-drying has also been used for waterlogged archaeological leather often after treatment with Na2.EDTA and impregnation with PEG; but the treated leather sometimes suffers from “excessive drying......” becoming too stiff and brittle. The aim of this study was to examine the effect of a conventional freeze-drying method against an alternative freeze-drying method that preserves the natural moisture content of the leather. Both new and archaeological waterlogged leather were included in the study...... suggest that the process which takes place within the leather during the freeze-drying in not actual freeze-drying, but rather a sophisticated way of distributing the impregnating agent. The pure ice phase freezes out, but the impregnating agent remains liquid as the temperature does not become low enough...

  12. Impact of the freeze-drying process on product appearance, residual moisture content, viability, and batch uniformity of freeze-dried bacterial cultures safeguarded at culture collections.

    Science.gov (United States)

    Peiren, Jindrich; Hellemans, Ann; De Vos, Paul

    2016-07-01

    In this study, causes of collapsed bacterial cultures in glass ampoules observed after freeze-drying were investigated as well as the influence of collapse on residual moisture content (RMC) and viability. Also, the effect of heat radiation and post freeze-drying treatments on the RMC was studied. Cake morphologies of 21 bacterial strains obtained after freeze-drying with one standard protocol could be classified visually into four major types: no collapse, porous, partial collapse, and collapse. The more pronounced the collapse, the higher residual moisture content of the freeze-dried product, ranging from 1.53 % for non-collapsed products to 3.62 % for collapsed products. The most important cause of collapse was the mass of the inserted cotton plug in the ampoule. Default cotton plugs with a mass between 21 and 30 mg inside the ampoule did not affect the viability of freeze-dried Aliivibrio fischeri LMG 4414(T) compared to ampoules without cotton plugs. Cotton plugs with a mass higher than 65 mg inside the ampoule induced a full collapsed product with rubbery look (melt-back) and decreasing viability during storage. Heat radiation effects in the freeze-drying chamber and post freeze-drying treatments such as exposure time to air after freeze-drying and manifold drying time prior to heat sealing of ampoules influenced the RMC of freeze-dried products. To produce uniform batches of freeze-dried bacterial strains with intact cake structures and highest viabilities, inserted cotton plugs should not exceed 21 mg per ampoule. Furthermore, heat radiation effects should be calculated in the design of the primary drying phase and manifold drying time before heat sealing should be determined as a function of exposure time to air.

  13. Analysis of the moisture evaporation process during vacuum freeze-drying of koumiss and shubat

    Science.gov (United States)

    Shingisov, Azret Utebaevich; Alibekov, Ravshanbek Sultanbekovich

    2017-05-01

    The equation for the calculating of a moisture evaporation rate in the vacuum freeze-drying, wherein as a driving force instead of the generally accepted in the drying theory of ∆t temperature difference, ∆p pressure difference, ∆c concentration difference, a difference of water activity in the product and the relative air humidity (a_{{w}} - \\varphi) is suggested. By using the proposed equation, the processes of vacuum freeze-drying of koumiss and shubat were analyzed, and it was found two drying periods: constant and falling. On the first drying period, a moisture evaporation rate of koumiss is j = 2.75 × 10-3 kg/(m2 h) and of shubat is j = 2.37 × 10-3 kg/(m2 h). On the second period, values decrease for koumiss from j = 2.65 × 10-3 kg/(m2 h) to j = 1.60 × 10-3 kg/(m2 h), and for shubat from j = 2.25 × 10-3 kg/(m2 h) to j = 1.62 × 10-3 kg/(m2 h). Specific humidity for koumiss is ueq = 0.61 kg/kg and for shubat is ueq = 0.58 kg/kg. The comparative analyze of the experimental data of the moisture evaporation rate versus the theoretical calculation shows that the approximation reliability is R2 = 0.99. Consequently, the proposed equation is useful for the analyzing a moisture evaporation rate during a vacuum freeze-drying of dairy products, including cultured milk foods.

  14. Analysis of the moisture evaporation process during vacuum freeze-drying of koumiss and shubat

    Science.gov (United States)

    Shingisov, Azret Utebaevich; Alibekov, Ravshanbek Sultanbekovich

    2016-10-01

    The equation for the calculating of a moisture evaporation rate in the vacuum freeze-drying, wherein as a driving force instead of the generally accepted in the drying theory of ∆t temperature difference, ∆p pressure difference, ∆c concentration difference, a difference of water activity in the product and the relative air humidity (a_{w} - φ) is suggested. By using the proposed equation, the processes of vacuum freeze-drying of koumiss and shubat were analyzed, and it was found two drying periods: constant and falling. On the first drying period, a moisture evaporation rate of koumiss is j = 2.75 × 10-3 kg/(m2 h) and of shubat is j = 2.37 × 10-3 kg/(m2 h). On the second period, values decrease for koumiss from j = 2.65 × 10-3 kg/(m2 h) to j = 1.60 × 10-3 kg/(m2 h), and for shubat from j = 2.25 × 10-3 kg/(m2 h) to j = 1.62 × 10-3 kg/(m2 h). Specific humidity for koumiss is ueq = 0.61 kg/kg and for shubat is ueq = 0.58 kg/kg. The comparative analyze of the experimental data of the moisture evaporation rate versus the theoretical calculation shows that the approximation reliability is R2 = 0.99. Consequently, the proposed equation is useful for the analyzing a moisture evaporation rate during a vacuum freeze-drying of dairy products, including cultured milk foods.

  15. Freeze-Drying Above the Glass Transition Temperature in Amorphous Protein Formulations While Maintaining Product Quality and Improving Process Efficiency.

    Science.gov (United States)

    Depaz, Roberto A; Pansare, Swapnil; Patel, Sajal Manubhai

    2016-01-01

    This study explored the ability to conduct primary drying during lyophilization at product temperatures above the glass transition temperature of the maximally freeze-concentrated solution (Tg′) in amorphous formulations for four proteins from three different classes. Drying above Tg′ resulted in significant reductions in lyophilization cycle time. At higher protein concentrations, formulations freeze dried above Tg′ but below the collapse temperature yielded pharmaceutically acceptable cakes. However, using an immunoglobulin G type 4 monoclonal antibody as an example, we found that as protein concentration decreased, minor extents of collapse were observed in formulations dried at higher temperatures. No other impacts to product quality, physical stability, or chemical stability were observed in this study among the different drying conditions for the different proteins. Drying amorphous formulations above Tg′, particularly high protein concentration formulations, is a viable means to achieve significant time and cost savings in freeze-drying processes.

  16. Investigation of the process of vacuum freeze drying of bacterial concentrates for the meat industry with cryogenic freezing

    Directory of Open Access Journals (Sweden)

    V. V. Poymanov

    2016-01-01

    Full Text Available The research results of the nutritional value of the products manufactured are presented in the article. The main directions of bacterial concentrates application in the meat industry were determined. The analysis of starter cultures was given. The range of products manu-factured with bacterial concentrates was analyzed. It was shown that the introduction of innovative technologies will enable dynamic development of both large and small enterprises, which will create prerequisites for the growth of the Russian market of meat products. Economic efficiency of the studied substances treatment methods was proved. The relevance of the development of technology of pro-duction of dry bacterial concentrates with cryogenic freezing was proved. An integrated approach to the development of competitive domestic technologies and equipment for cryofreezing and sublimation dehydration by the use of granulation for the intensification of the internal heat and mass transfer, reducing specific energy consumption through the use of a combined cold supply system was pro-posed. Results of the study of the kinetics of the freezing process with the traditional method and cryofreezing are given in the paper. Rational parameters of the cryofreezing process were proposed. The optimum composition of cryoprotective medium was recommended. The research of the process of bacterial concentrate vacuum sublimation dehydration in the layer and granular form were conducted. The research confirmed that the use of the cryofreezing and granulation can increase the number of viable microorganisms in the bacterial concentrate and reduce the drying time. Rational vacuum sublimation dehydration modes were proposed. Methods of reduc-ing the defects of the processed products and improvement of the efficiency of production facilities were specified. Quality indicators of dried bacterial concentrates were given. The results obtained allow to carry out engineering calculations

  17. Effects of physical parameters on the heat and mass transfer characteristics in freeze-drying processes of fruits and vegetables

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yuming; Liu, Lijuan; Liang, Li [Shanxi Agricultural Univ. (China). Coll. of Engineering and Technology], E-mail: guoyuming99@sina.com

    2008-07-01

    Studying the effects mechanism of material physical parameters on the heat and mass transfer characteristics, the process parameters and energy consumption during freeze-drying process is of importance in improving the vacuum freeze-drying process with low energy consumption. In this paper, the sliced and mashed carrots of one variety were selected to perform the vacuum freeze-drying experiments. First, the variation laws of surface temperatures and sublimation front temperatures of the two shapes samples during the freeze-drying processes were analyzed, and it was verified that the process of sliced carrots is controlled by mass transfer, while that of the mashed ones is heat-transfer control. Second, the variations of water loss rate, energy consumption and temperature of the two shapes samples under the appropriate heating plate temperature and the different drying chamber pressure were analyzed. In addition, the effects of thermal conductivity and thermal diffusivity on freeze-drying time and process parameters were discussed by utilizing the theory of heat and mass transfer. In conclusion, under the heat transfer condition, the temperature of the heating plate should be as high as possible within the permitted range, and the drying chamber pressure should be set at optimal level. While under the mass transport-limited condition, the pressure level need to be altered in short time. (author)

  18. Advanced approach to build the design space for the primary drying of a pharmaceutical freeze-drying process.

    Science.gov (United States)

    Fissore, Davide; Pisano, Roberto; Barresi, Antonello A

    2011-11-01

    This paper deals with the design space of a pharmaceutical freeze-drying process. Mathematical modeling is used to investigate the effect of the operating conditions [shelf temperature (T(shelf)) and chamber pressure (P(c))] on product temperature (that has to remain below a limit value) and sublimation flux (that has to be lower than a level that would cause choked flow). The algorithm takes into account the variation of the design space with time due to the increase in the dried layer thickness. Besides T(shelf) and P(c), the dried layer thickness is used as the third coordinate of the diagram, thus resulting in just one graph that can be used to build recipes with variable operating conditions, as well as to analyze the effect of process failures. Such results are compared with those obtained when the variation of the design space with time is not accounted for; in this case, the design space comprises those operating conditions that fulfill the operation constraints throughout primary drying, thus giving a much more conservative recipe when designing the process or potentially misleading results when analyzing process failures. Finally, the proposed method has been used to design, and experimentally validate, a recipe for a pharmaceutical formulation. Copyright © 2011 Wiley-Liss, Inc.

  19. Fabrication of Li{sub 2}TiO{sub 3} pebbles by a freeze drying process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Jin, E-mail: lee@mokpo.ac.kr [Department of Advanced Materials Science and Engineering, Mokpo National University, Muan 534-729 (Korea, Republic of); Park, Yi-Hyun [National Fusion Research Institute, Daejeon 305-806 (Korea, Republic of); Yu, Min-Woo [Department of Advanced Materials Science and Engineering, Mokpo National University, Muan 534-729 (Korea, Republic of)

    2013-11-15

    Li{sub 2}TiO{sub 3} pebbles were successfully fabricated by using a freeze drying process. The Li{sub 2}TiO{sub 3} slurry was prepared using a commercial powder of particle size 0.5–1.5 μm and the pebble pre-form was prepared by dropping the slurry into liquid nitrogen through a syringe needle. The droplets were rapidly frozen, changing their morphology to spherical pebbles. The frozen pebbles were dried at −10 °C in vacuum. To make crack-free pebbles, some glycerin was employed in the slurry, and long drying time and a low vacuum condition were applied in the freeze drying process. In the process, the solid content in the slurry influenced the spheroidicity of the pebble green body. The dried pebbles were sintered at 1200 °C in an air atmosphere. The sintered pebbles showed almost 40% shrinkage. The sintered pebbles revealed a porous microstructure with a uniform pore distribution and the sintered pebbles were crushed under an average load of 50 N in a compressive strength test. In the present study, a freeze drying process for fabrication of spherical Li{sub 2}TiO{sub 3} pebbles is introduced. The processing parameters, such as solid content in the slurry and the conditions of freeze drying and sintering, are also examined.

  20. In-line and real-time process monitoring of a freeze drying process using Raman and NIR spectroscopy as complementary process analytical technology (PAT) tools.

    Science.gov (United States)

    De Beer, T R M; Vercruysse, P; Burggraeve, A; Quinten, T; Ouyang, J; Zhang, X; Vervaet, C; Remon, J P; Baeyens, W R G

    2009-09-01

    The aim of the present study was to examine the complementary properties of Raman and near infrared (NIR) spectroscopy as PAT tools for the fast, noninvasive, nondestructive and in-line process monitoring of a freeze drying process. Therefore, Raman and NIR probes were built in the freeze dryer chamber, allowing simultaneous process monitoring. A 5% (w/v) mannitol solution was used as model for freeze drying. Raman and NIR spectra were continuously collected during freeze drying (one Raman and NIR spectrum/min) and the spectra were analyzed using principal component analysis (PCA) and multivariate curve resolution (MCR). Raman spectroscopy was able to supply information about (i) the mannitol solid state throughout the entire process, (ii) the endpoint of freezing (endpoint of mannitol crystallization), and (iii) several physical and chemical phenomena occurring during the process (onset of ice nucleation, onset of mannitol crystallization). NIR spectroscopy proved to be a more sensitive tool to monitor the critical aspects during drying: (i) endpoint of ice sublimation and (ii) monitoring the release of hydrate water during storage. Furthermore, via NIR spectroscopy some Raman observations were confirmed: start of ice nucleation, end of mannitol crystallization and solid state characteristics of the end product. When Raman and NIR monitoring were performed on the same vial, the Raman signal was saturated during the freezing step caused by reflected NIR light reaching the Raman detector. Therefore, NIR and Raman measurements were done on a different vial. Also the importance of the position of the probes (Raman probe above the vial and NIR probe at the bottom of the sidewall of the vial) in order to obtain all required critical information is outlined. Combining Raman and NIR spectroscopy for the simultaneous monitoring of freeze drying allows monitoring almost all critical freeze drying process aspects. Both techniques do not only complement each other, they also

  1. Effects of formulation and process factors on the crystal structure of freeze-dried Myo-inositol.

    Science.gov (United States)

    Izutsu, Ken-Ichi; Yomota, Chikako; Okuda, Haruhiro; Kawanishi, Toru; Yamaki, Takuya; Ohdate, Ryohei; Yu, Zhaokun; Yonemochi, Etsuo; Terada, Katsuhide

    2014-08-01

    The objective of this study was to elucidate effects of formulation and process variables on the physical forms of freeze-dried myo-inositol. Physical properties of myo-inositol in frozen solutions, freeze-dried solids, and cooled heat-melt solids were characterized by powder X-ray diffraction (PXRD), thermal analysis (differential scanning calorimetry [DSC] and thermogravimetric), and simultaneous PXRD-DSC analysis. Cooling of heat-melt myo-inositol produced two forms of metastable anhydrate crystals that change to stable form (melting point 225 °C-228 °C) with transition exotherms at around 123 °C and 181 °C, respectively. Freeze-drying of single-solute aqueous myo-inositol solutions after rapid cooling induced crystallization of myo-inositol as metastable anhydrate (transition at 80 °C-125 °C) during secondary drying segment. Contrarily, postfreeze heat treatment (i.e., annealing) induced crystallization of myo-inositol dihydrate. Removal of the crystallization water during the secondary drying produced the stable-form myo-inositol anhydrate crystal. Shelf-ramp slow cooling of myo-inositol solutions resulted in the stable and metastable anhydrous crystal solids depending on the solute concentrations and the solution volumes. Colyophilization with phosphate buffer retained myo-inositol in the amorphous state. Crystallization in different process segments varies crystal form of freeze-dried myo-inositol solids.

  2. A batch modelling approach to monitor a freeze-drying process using in-line Raman spectroscopy.

    Science.gov (United States)

    Sarraguça, Mafalda Cruz; De Beer, Thomas; Vervaet, Chris; Remon, Jean-Paul; Lopes, João Almeida

    2010-11-15

    Freeze-drying or lyophilisation is a batch wise industrial process used to remove water from solutions, hence stabilizing the solutes for distribution and storage. The objective of the present work was to outline a batch modelling approach to monitor a freeze-drying process in-line and in real-time using Raman spectroscopy. A 5% (w/v) D-mannitol solution was freeze-dried in this study as model. The monitoring of a freeze-drying process using Raman spectroscopy allows following the product behaviour and some process evolution aspects by detecting the changes of the solutes and solvent occurring during the process. Herewith, real-time solid-state characterization of the final product is also possible. The timely spectroscopic measurements allowed the differentiation between batches operated in normal process conditions and batches having deviations from the normal trajectory. Two strategies were employed to develop batch models: partial least squares (PLS) using the unfolded data and parallel factor analysis (PARAFAC). It was shown that both strategies were able to developed batch models using in-line Raman spectroscopy, allowing to monitor the evolution in real-time of new batches. However, the computational effort required to develop the PLS model and to evaluate new batches using this model is significant lower compared to the PARAFAC model. Moreover, PLS scores in the time mode can be computed for new batches, while using PARAFAC only the batch mode scores can be determined for new batches.

  3. Spray Freeze-drying - The Process of Choice for Low Water Soluble Drugs?

    Energy Technology Data Exchange (ETDEWEB)

    Leuenberger, H. [University of Basel, Pharmacenter, Institute of Pharmaceutical Technology (Switzerland)], E-mail: hans.leuenberger@unibas.ch

    2002-04-15

    Most of the novel highly potent drugs, developed on the basis of modern molecular medicine, taking into account cell surface recognition techniques, show poor water solubility. A chemical modification of the drug substance enhancing the solubility often decreases the pharmacological activity. Thus, as an alternative an increase of the solubility can be obtained by the reduction of the size of the drug particles. Unfortunately, it is often difficult to obtain micro or nanosized drug particles by classical or more advanced crystallization using supercritical gases or by milling techniques. In addition, nanosized particles are often not physically stable and need to be stabilized in an appropriate matrix. Thus, it may be of interest to manufacture directly nanosized drug particles stabilized in an inert hydrophilic matrix, i.e. nanostructured and nanocomposite systems. Solid solutions and solid dispersions represent nanostructured and nanocomposite systems. In this context, the use of the vacuum-fluidized-bed technique for the spray-drying of a low water soluble drug cosolubilized with a hydrophilic excipient in a polar organic solvent is discussed. In order to avoid the use of organic solvents, a special spray-freeze-drying technique working at atmospheric pressure is presented. This process is very suitable for temperature and otherwise sensitive drugs such as pharmaproteins.

  4. Development of freeze dried vegetables

    Science.gov (United States)

    Larson, R. W.

    1970-01-01

    The development of freeze dried vegetables to be used in the Apollo food system is discussed. After the initial selection and screening of vegetables, several types of freeze dried vegetables were prepared in small batches. From these small batches, two vegetables were judged satisfactory for further testing and evaluation. These vegetables, mashed potatoes and asparagus, were subjected to storage at 100 deg plus or minus 5 F. for two weeks and then taste tested. The vegetables were also tested to determine if they complied with the microbiological requirements for Apollo food. The space food prototype production guide for the vegetables is submitted.

  5. Freeze-drying of lactic acid bacteria.

    Science.gov (United States)

    Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

    2015-01-01

    Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g., yogurt, cheese, fermented meats, and vegetables) and probiotic products, as well as for green chemistry applications. Freeze-drying or lyophilization is a convenient method for preservation of bacteria. By reducing water activity to values below 0.2, it allows long-term storage and low-cost distribution at suprazero temperatures, while minimizing losses in viability and functionality. Stabilization of bacteria via freeze-drying starts with the addition of a protectant solution to the bacterial suspension. Freeze-drying includes three steps, namely, (1) freezing of the concentrated and protected cell suspension, (2) primary drying to remove ice by sublimation, and (3) secondary drying to remove unfrozen water by desorption. In this chapter we describe a method for freeze-drying of lactic acid bacteria at a pilot scale, thus allowing control of the process parameters for maximal survival and functionality recovery.

  6. Optimization of Freeze-Drying Process Parameters for Qualitative Evaluation of Button Mushroom (Agaricus bisporus Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Ayon Tarafdar

    2017-01-01

    Full Text Available Button mushroom cubes of constant cross-sectional area (0.75 cm × 1.5 cm and varying thickness (2 mm, 5 mm, and 8 mm were freeze-dried. Pressure (0.04, 0.07, and 0.10 mbar, primary drying temperature (−2°C, −5°C, and −8°C, and secondary drying temperature (25°C, 28°C, and 31°C were taken as drying parameters. The protein, ascorbic acid, and antioxidant contents were taken as quality estimates for freeze-dried mushrooms. It was observed that the secondary drying temperature affected the protein (p<0.05 and antioxidant content (p<0.01 significantly, whereas all three freeze-drying parameters affected the ascorbic acid content with higher effect due to temperature parameters (p<0.01 as compared to pressure (p<0.05. The optimized values for protein, ascorbic acid, and antioxidant content obtained using response surface methodology were 7.28±0.56 mg/g, 26.92±0.87 mg/100 g, and 8.60±0.44 mg/g, respectively, as compared to 8.43±0.21 mg/g, 28.00±0.53 mg/100 g, and 9.10±0.10 mg/g, respectively, for fresh button mushrooms. The optimum values for process variables were obtained as 0.09 mbar, 0.36 cm, and −7.53°C and 25.03°C for pressure, sample thickness, and primary and secondary drying temperatures, respectively.

  7. Characteristics of sugar surfactants in stabilizing proteins during freeze-thawing and freeze-drying.

    Science.gov (United States)

    Imamura, Koreyoshi; Murai, Katsuyuki; Korehisa, Tamayo; Shimizu, Noriyuki; Yamahira, Ryo; Matsuura, Tsutashi; Tada, Hiroko; Imanaka, Hiroyuki; Ishida, Naoyuki; Nakanishi, Kazuhiro

    2014-06-01

    Sugar surfactants with different alkyl chain lengths and sugar head groups were compared for their protein-stabilizing effect during freeze-thawing and freeze-drying. Six enzymes, different in terms of tolerance against inactivation because of freeze-thawing and freeze-drying, were used as model proteins. The enzyme activities that remained after freeze-thawing and freeze-drying in the presence of a sugar surfactant were measured for different types and concentrations of sugar surfactants. Sugar surfactants stabilized all of the tested enzymes both during freeze-thawing and freeze-drying, and a one or two order higher amount of added sugar surfactant was required for achieving protein stabilization during freeze-drying than for the cryoprotection. The comprehensive comparison showed that the C10-C12 esters of sucrose or trehalose were the most effective through the freeze-drying process: the remaining enzyme activities after freeze-thawing and freeze-drying increased at the sugar ester concentrations of 1-10 and 10-100 μM, respectively, and increased to a greater extent than for the other surfactants at higher concentrations. Results also indicate that, when a decent amount of sugar was also added, the protein-stabilizing effect of a small amount of sugar ester through the freeze-drying process could be enhanced. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  8. Freeze-drying of live virus vaccines: A review.

    Science.gov (United States)

    Hansen, L J J; Daoussi, R; Vervaet, C; Remon, J-P; De Beer, T R M

    2015-10-13

    Freeze-drying is the preferred method for stabilizing live, attenuated virus vaccines. After decades of research on several aspects of the process like the stabilization and destabilization mechanisms of the live, attenuated viruses during freeze-drying, the optimal formulation components and process settings are still matter of research. The molecular complexity of live, attenuated viruses, the multiple destabilization pathways and the lack of analytical techniques allowing the measurement of physicochemical changes in the antigen's structure during and after freeze-drying mean that they form a particular lyophilization challenge. The purpose of this review is to overview the available information on the development of the freeze-drying process of live, attenuated virus vaccines, herewith focusing on the freezing and drying stresses the viruses can undergo during processing as well as on the mechanisms and strategies (formulation and process) that are used to stabilize them during freeze-drying.

  9. Freeze-Drying of L-Arginine/Sucrose-Based Protein Formulations, Part 2: Optimization of Formulation Design and Freeze-Drying Process Conditions for an L-Arginine Chloride-Based Protein Formulation System.

    Science.gov (United States)

    Stärtzel, Peter; Gieseler, Henning; Gieseler, Margit; Abdul-Fattah, Ahmad M; Adler, Michael; Mahler, Hanns-Christian; Goldbach, Pierre

    2015-12-01

    We recently reported that the presence of chloride counter ions in freeze-dried l-arginine/sucrose formulations provided the greatest protein stability, but led to low collapse temperatures and glass transition temperatures of the freeze concentrates. The objectives of this study were to identify l-arginine chloride-based formulations and optimize freeze-drying process conditions to deliver a freeze-dried product with good physical quality attributes (including cake appearance, residual moisture, and reconstitution time). Additional properties were tested such as thermal properties, cake microstructure, and protein physical stability. Excipient concentrations were varied with and without a model protein (bovine serum albumin, BSA). Formulations were frozen with and without annealing or with and without controlled nucleation. Primary drying was conducted at high and low shelf temperature. Cakes with least defects and optimum physical attributes were achieved when protein to excipient ratios were high. Controlled nucleation led to elegant cakes for most systems at a low shelf temperature. Replacing BSA by a monoclonal antibody showed that protein (physical) stability was slightly improved under stress storage temperature (i.e., 40°C) in the presence of a low concentration of l-arginine in a sucrose-based formulation. At higher l-arginine concentrations, cake defects increased. Using optimized formulation design, addition of l-arginine chloride to a sucrose-based formulation provided elegant cakes and benefits for protein stability.

  10. Mechanisms of deterioration of nutrients. [of freeze dried foods

    Science.gov (United States)

    Karel, M.; Flink, J. M.

    1976-01-01

    Methods which produce freeze dried foods of improved quality were examined with emphasis on storage stability. Specific topics discussed include: microstructure of freeze dried systems, investigation of structural changes in freeze dried systems, artificial food matrices, osmotic preconcentration to yield improved quality freeze dried fruits, and storage stability of osmotically preconcentrated freeze dried fruits.

  11. Application of Optical Coherence Tomography Freeze-Drying Microscopy for Designing Lyophilization Process and Its Impact on Process Efficiency and Product Quality.

    Science.gov (United States)

    Korang-Yeboah, Maxwell; Srinivasan, Charudharshini; Siddiqui, Akhtar; Awotwe-Otoo, David; Cruz, Celia N; Muhammad, Ashraf

    2017-08-07

    Optical coherence tomography freeze-drying microscopy (OCT-FDM) is a novel technique that allows the three-dimensional imaging of a drug product during the entire lyophilization process. OCT-FDM consists of a single-vial freeze dryer (SVFD) affixed with an optical coherence tomography (OCT) imaging system. Unlike the conventional techniques, such as modulated differential scanning calorimetry (mDSC) and light transmission freeze-drying microscopy, used for predicting the product collapse temperature (Tc), the OCT-FDM approach seeks to mimic the actual product and process conditions during the lyophilization process. However, there is limited understanding on the application of this emerging technique to the design of the lyophilization process. In this study, we investigated the suitability of OCT-FDM technique in designing a lyophilization process. Moreover, we compared the product quality attributes of the resulting lyophilized product manufactured using Tc, a critical process control parameter, as determined by OCT-FDM versus as estimated by mDSC. OCT-FDM analysis revealed the absence of collapse even for the low protein concentration (5 mg/ml) and low solid content formulation (1%w/v) studied. This was confirmed by lab scale lyophilization. In addition, lyophilization cycles designed using Tc values obtained from OCT-FDM were more efficient with higher sublimation rate and mass flux than the conventional cycles, since drying was conducted at higher shelf temperature. Finally, the quality attributes of the products lyophilized using Tc determined by OCT-FDM and mDSC were similar, and product shrinkage and cracks were observed in all the batches of freeze-dried products irrespective of the technique employed in predicting Tc.

  12. Sucrose Diffusion in Decellularized Heart Valves for Freeze-Drying.

    Science.gov (United States)

    Wang, Shangping; Oldenhof, Harriëtte; Goecke, Tobias; Ramm, Robert; Harder, Michael; Haverich, Axel; Hilfiker, Andres; Wolkers, Willem Frederik

    2015-09-01

    Decellularized heart valves can be used as starter matrix implants for heart valve replacement therapies in terms of guided tissue regeneration. Decellularized matrices ideally need to be long-term storable to assure off-the-shelf availability. Freeze-drying is an attractive preservation method, allowing storage at room temperature in a dried state. However, the two inherent processing steps, freezing and drying, can cause severe damage to extracellular matrix (ECM) proteins and the overall tissue histoarchitecture and thus impair biomechanical characteristics of resulting matrices. Freeze-drying therefore requires a lyoprotective agent that stabilizes endogenous structural proteins during both substeps and that forms a protective glassy state at room temperature. To estimate incubation times needed to infiltrate decellularized heart valves with the lyoprotectant sucrose, temperature-dependent diffusion studies were done using Fourier transform infrared spectroscopy. Glycerol, a cryoprotective agent, was studied for comparison. Diffusion of both protectants was found to exhibit Arrhenius behavior. The activation energies of sucrose and glycerol diffusion were found to be 15.9 and 37.7 kJ·mol(-1), respectively. It was estimated that 4 h of incubation at 37°C is sufficient to infiltrate heart valves with sucrose before freeze-drying. Application of a 5% sucrose solution was shown to stabilize acellular valve scaffolds during freeze-drying. Such freeze-dried tissues, however, displayed pores, which were attributed to ice crystal damage, whereas vacuum-dried scaffolds in comparison revealed no pores after drying and rehydration. Exposure to a hygroscopic sucrose solution (80%) before freeze-drying was shown to be an effective method to diminish pore formation in freeze-dried ECMs: matrix structures closely resembled those of control samples that were not freeze-dried. Heart valve matrices were shown to be in a glassy state after drying, suggesting that they can

  13. Drying of α-amylase by spray drying and freeze-drying - a comparative study

    Directory of Open Access Journals (Sweden)

    S. S. de Jesus

    2014-09-01

    Full Text Available This study is aimed at comparing two traditional methods of drying of enzymes and at verifying the efficiency of each one and their advantages and disadvantages. The experiments were performed with a laboratory spray dryer and freeze-dryer using α-amylase as the model enzyme. An experimental design in star revealed that spray drying is mainly influenced by the inlet air temperature and feed flow rate, which were considered to be the main factors influencing the enzymatic activity and water activity; the long period of material exposure to high temperatures causes a partial activity loss. In the experiments of freeze drying, three methods of freezing were used (freezer, acetone and dry ice, and liquid nitrogen and samples subsequently freeze-dried for times ranging between 0-24 hours. The product obtained from the two techniques showed high enzymatic activity and low water activity. For the drying of heat-resistant enzymes, in which the product to be obtained does not have high added value, spray drying may be more economically viable because, in the freeze drying process, the process time can be considered as a limiting factor when choosing a technique.

  14. Well-plate freeze-drying

    DEFF Research Database (Denmark)

    Trnka, Hjalte; Rantanen, Jukka; Grohganz, Holger

    2015-01-01

    due to increasing amount of amorphous matter in the samples was observed in both vials and well plates. Cake collapse was found to be representative in well plates and could be effectively quantified using image analysis. Reconstitution time was also found to be equal in all three platforms. Finally......Abstract Context: Freeze-drying in presence of excipients is a common practice to stabilize biomacromolecular formulations. The composition of this formulation is known to affect the quality of the final product. Objective: The aim of this study was to evaluate freeze-drying in well-plates...... as a high throughput platform for formulation screening of freeze-dried products. Methods: Model formulations consisting of mannitol, sucrose and bovine serum albumin were freeze-dried in brass well plates, plastic well plates and vials. Physical properties investigated were solid form, residual moisture...

  15. Robustness testing in pharmaceutical freeze-drying: inter-relation of process conditions and product quality attributes studied for a vaccine formulation.

    Science.gov (United States)

    Schneid, Stefan C; Stärtzel, Peter M; Lettner, Patrick; Gieseler, Henning

    2011-01-01

    The recent US Food and Drug Administration (FDA) legislation has introduced the evaluation of the Design Space of critical process parameters in manufacturing processes. In freeze-drying, a "formulation" is expected to be robust when minor deviations of the product temperature do not negatively affect the final product quality attributes. To evaluate "formulation" robustness by investigating the effect of elevated product temperature on product quality using a bacterial vaccine solution. The vaccine solution was characterized by freeze-dry microscopy to determine the critical formulation temperature. A conservative cycle was developed using the SMART™ mode of a Lyostar II freeze dryer. Product temperature was elevated to imitate intermediate and aggressive cycle conditions. The final product was analyzed using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), Karl Fischer, and modulated differential scanning calorimetry (MDSC), and the life cell count (LCC) during accelerated stability testing. The cakes processed at intermediate and aggressive conditions displayed larger pores with microcollapse of walls and stronger loss in LCC than the conservatively processed product, especially during stability testing. For all process conditions, a loss of the majority of cells was observed during storage. For freeze-drying of life bacterial vaccine solutions, the product temperature profile during primary drying appeared to be inter-related to product quality attributes.

  16. Evaluation of high pressure processing, freezing, and fermentation/drying on viability of Trichinella spiralis larvae in raw pork and in Genoa salami

    Science.gov (United States)

    We evaluated high pressure processing (HPP), freezing, and fermentation/drying to inactivate Trichinella spiralis larvae in both infected pig muscle and in Genoa salami produced with trichinae infected pork. In part A, in each of two trials 10 gram portions (2 replicates per treatment) of fresh pig ...

  17. Effect of freeze-dried leek powder (FDLP) and nitrite level on processing and quality characteristics of fermented sausages.

    Science.gov (United States)

    Tsoukalas, D S; Katsanidis, E; Marantidou, S; Bloukas, J G

    2011-02-01

    Fermented sausages were produced with 0.84% and 1.68% freeze-dried leek powder (FDLP), providing 75 and 150 mg/kg NaNO(3), respectively, and three levels of added nitrite (0, 75, and 150 mg/kg NaNO(2). A control treatment was also produced with 150 mg/kg NaNO(2). Sausages with FDLP were darker and yellower (psausages (pfermented sausages, as it results in a 50% reduction in added nitrite.

  18. Effect of co-solutes and process variables on crystallinity and the crystal form of freeze-dried myo-inositol.

    Science.gov (United States)

    Izutsu, Ken-Ichi; Kusano, Riho; Arai, Ryoko; Yoshida, Hiroyuki; Ito, Masataka; Shibata, Hiroko; Sugano, Kiyohiko; Goda, Yukihiro; Terada, Katsuhide

    2016-07-25

    The purpose of this study was to elucidate how co-solutes affect the crystallization of small solute molecules during freeze-drying and subsequent storage. Crystallization profiles of myo-inositol and its mixture with dextran 40k in frozen solutions and dried solids were assessed by thermal analysis (DSC), powder-X-ray diffraction, and simultaneous DSC and PXRD analysis. Higher mass ratios of dextran maintained myo-inositol in the non-crystalline mixture state, in frozen solutions, during freeze-drying process, and exposure of dried solids to higher temperatures. Co-lyophilization with a lower mass ratio of dextran resulted in solids containing a variety of myo-inositol crystal forms and crystallinity depending on the composition and thermal history of the process. Heating of some inositol-rich amorphous solids showed crystallization of myo-inositol in the metastable form and its transition to stable form before melting. Heat-treatment of inositol-rich frozen solutions resulted in high crystallinity stable-form inositol solids, leaving dextran in the amorphous state. Sufficient direct molecular interactions (e.g., hydrogen bonding) should explain the stability of dextran-rich amorphous solids. Optimizing solute composition and processes should be a potent way to control crystal form and crystallinity of components in freeze-dried formulations.

  19. 胡萝卜冰温干燥实验研究%Study on Controlled Freezing-point Dried Processing of Carrot

    Institute of Scientific and Technical Information of China (English)

    王丰; 李保国; 申江; 苏树强; 张明融

    2012-01-01

    采用干燥方法可将食品脱水进行长期保存。热风干燥不适合热敏性食品,且干燥后产品品质较差,而采用冷冻干燥,虽能克服上述缺点,但干燥时间长,效率低。文中提出一种冰温干燥新技术,以胡萝卜为实验原料进行了冰温干燥实验研究,并与真空冷冻干燥及热风干燥进行了对比。实验结果表明:在150 Pa的压力下,经过4 h冰温干燥,得到的胡萝卜含水率为4.8%,其复水性优于热风干燥,其干燥样品中的Vc及胡萝卜素等营养成分损失少,外观色泽优良,干燥时间比冷冻干燥显著减少。%Drying method is used for dehydrating food for long-term preservation.Hot-air drying is not suitable for drying heat-sensitive food,and the product qualities is poor;vacuum freeze-drying is able to overcome these disadvantages,but to much time and low efficiency.This paper provides a new drying technology,controlled freezing-point drying.Taken carrot as the experimental material,the controlled freezing-point dried processing is studied.The result was compared with the vacuum freeze-drying and hot-air drying.The result were : at the pressure of 150 Pa,after 4 hours of drying,water content of carrot was 4.8%.The results also showed that rehydration was better,Vc and carotene in carrots were merely lost,the carrots kept nice color and appearance.Compared with freeze-drying,drying time significantly reduced.

  20. 猪皮胶原海绵的冷冻干燥工艺%Studies on Collagen Sponge Freeze-drying Process

    Institute of Scientific and Technical Information of China (English)

    杨田义; 郭柏松; 张路; 代龙

    2011-01-01

    目的:优选猪皮胶原海绵的最佳冷冻干燥工艺.方法:以吸水性、复水性值为指标,通过正交试验法对猪皮胶原海绵的冷冻干燥工艺参数进行筛选,优选出猪皮胶原海绵的最佳冷冻干燥工艺.结果:预冻速率0.35℃·min(-1),预冻时间1.5h,预冻最低温度-35℃,一次升华温度-10℃.结论:优选的冷冻干燥工艺制备的猪皮胶原海绵疏松多孔,吸水性、复水性良好.%Objective: To optimize selection of collagen sponge freeze-drying process, such as collagen protein molecules of freeze-drying reference. Method: Orthogonal test was used to choose the best collagen sponge freeze-drying process with water imbibition and re-hydration values as index. Result: The rate of pre-freezing was 0. 35 ℃ · min- 1, the duration of pre-freezing was 1.5 h, the lowest temperature of pre-freezing was - 35 ℃ and the temperature of the first sublimation was - 10 ℃. Conclusion: The pigskin collagen sponge produced by the freezedrying process which has been chosen is osteoporosis and porous, the water imbibition and re-hydration of the pigskin collagen sponge are well.

  1. Sensory and physico-chemical characteristics of desserts prepared with egg products processed by freeze and spray drying

    Directory of Open Access Journals (Sweden)

    Marcelo Nunes de Jesús

    2013-09-01

    Full Text Available In this work, three freeze-dried (FD egg products (whole egg (WE, egg yolk (EY and egg white (EW were obtained and the acceptability of confections prepared with each was evaluated. Sensory analyses for confections were performed by hedonic testing with fifty panelists in each evaluation. The studied confections were: Condensed Milk Pudding (P, Quindim (Q and Meringue (M. The results obtained for confections made with FD egg products were compared with the achieved through other formulations of the same desserts made with fresh (F or spray-dried (SD egg products. The sensory analysis results for confections made with FD egg products showed good acceptance by panelists. A principal component analysis of the sensory evaluation data was carried out to identify similarities between the different egg products. The PCA supported the conclusion that FD egg products can substitute their fresh and SD counterparts in dessert formulations with good acceptability while keeping the advantages conferred by the freeze-drying method.

  2. Effects of freezing, freeze drying and convective drying on in vitro gastric digestion of apples.

    Science.gov (United States)

    Dalmau, Maria Esperanza; Bornhorst, Gail M; Eim, Valeria; Rosselló, Carmen; Simal, Susana

    2017-01-15

    The influence of processing (freezing at -196°C in liquid N2, FN sample; freeze-drying at -50°C and 30Pa, FD sample; and convective drying at 60°C and 2m/s, CD sample) on apple (var. Granny Smith) behavior during in vitro gastric digestion was investigated. Dried apples (FD and CD samples) were rehydrated prior to digestion. Changes in carbohydrate composition, moisture, soluble solids, acidity, total polyphenol content (TPC), and antioxidant activity (AA) of apple samples were measured at different times during digestion. Processing resulted in disruption of the cellular structure during digestion, as observed by scanning electron microscopy, light microscopy, and changes in carbohydrate composition. Moisture content increased (6-11% dmo), while soluble solids (55-78% dmo), acidity (44-72% dmo), total polyphenol content (30-61% dmo), and antioxidant activity (41-87%) decreased in all samples after digestion. Mathematical models (Weibull and exponential models) were used to better evaluate the influence of processing on apple behavior during gastric digestion.

  3. The effect of excipients on the stability and aerosol performance of salmon calcitonin dry powder inhalers prepared via the spray freeze drying process

    Directory of Open Access Journals (Sweden)

    Poursina Narges

    2016-06-01

    Full Text Available Spray freeze drying was developed to produce dry powders suitable for applications such as inhalation delivery. In the current study, the spray freeze drying technique was employed to produce inhalable salmon calcitonin microparticles. Effects of the carrier type, concentration of hydroxyl propyl-β-cyclodextrin and the presence of Tween 80 on the chemical and structural stability, as well as on the aerosol performance of the particles were investigated. The results indicated that hydroxyl propyl-β-cyclodextrin had the most important effect on the chemical stability of the powder and strongly increased its stability by increasing its concentration in the formulation. Chemically stable formulations (over 90 % recovery were selected for further examinations. Fluorescence spectroscopy and circular dichroism suggested that the formulations were structurally stable. Aerosol performance showed that the Tween-free powders produced higher fine particle fraction values than the formulations containing Tween (53.7 vs. 41.92 % for trehalose content and 52.85 vs. 43.06 % for maltose content.

  4. The effect of excipients on the stability and aerosol performance of salmon calcitonin dry powder inhalers prepared via the spray freeze drying process.

    Science.gov (United States)

    Poursina, Narges; Vatanara, Alireza; Rouini, Mohammad Reza; Gilani, Kambiz; Najafabadi, Abdolhossein Rouholamini

    2016-06-01

    Spray freeze drying was developed to produce dry powders suitable for applications such as inhalation delivery. In the current study, the spray freeze drying technique was employed to produce inhalable salmon calcitonin microparticles. Effects of the carrier type, concentration of hydroxyl propyl-β-cyclodextrin and the presence of Tween 80 on the chemical and structural stability, as well as on the aerosol performance of the particles were investigated. The results indicated that hydroxyl propyl-β-cyclodextrin had the most important effect on the chemical stability of the powder and strongly increased its stability by increasing its concentration in the formulation. Chemically stable formulations (over 90 % recovery) were selected for further examinations. Fluorescence spectroscopy and circular dichroism suggested that the formulations were structurally stable. Aerosol performance showed that the Tween-free powders produced higher fine particle fraction values than the formulations containing Tween (53.7 vs. 41.92 % for trehalose content and 52.85 vs. 43.06 % for maltose content).

  5. The influence of freezing rates on bovine pericardium tissue Freeze-drying

    Directory of Open Access Journals (Sweden)

    Camila Figueiredo Borgognoni

    2009-12-01

    Full Text Available The bovine pericardium has been used as biomaterial in developing bioprostheses. Freeze-drying is a drying process that could be used for heart valve's preservation. The maintenance of the characteristics of the biomaterial is important for a good heart valve performance. This paper describes the initial step in the development of a bovine pericardium tissue freeze-drying to be used in heart valves. Freeze-drying involves three steps: freezing, primary drying and secondary drying. The freezing step influences the ice crystal size and, consequently, the primary and secondary drying stages. The aim of this work was to investigate the influence of freezing rates on the bovine pericardium tissue freeze-drying parameters. The glass transition temperature and the structural behaviour of the lyophilized tissues were determined as also primary and secondary drying time. The slow freezing with thermal treatment presented better results than the other freeze-drying protocols.O pericárdio bovino é um material utilizado na fabricação de biopróteses. A liofilização é um método de secagem que vem sendo estudado para a conservação de válvulas cardíacas. A preservação das características do biomaterial é de fundamental importância no bom funcionamento das válvulas. Este artigo é a primeira etapa do desenvolvimento do ciclo de liofilização do pericárdio bovino. Liofilização é o processo de secagem no qual a água é removida do material congelado por sublimação e desorção da água incongelável, sob pressão reduzida. O congelamento influencia o tamanho do cristal de gelo e, consequentemente, a secagem primária e secundária. O objetivo deste estudo foi verificar a influência das taxas de congelamento nos parâmetros de liofilização do pericárdio bovino. Determinou-se a temperatura de transição vítrea e o comportamento estrutural do pericárdio bovino liofilizado. Determinou-se o tempo da secagem primária e secundária. O

  6. Sperm Preservation using Freeze-Drying Method

    Directory of Open Access Journals (Sweden)

    TAKDIR SAILI

    2005-03-01

    Full Text Available Since the discovery of cryopreservation method for bull semen, cryopreservation become an alternative method for maintaining gamet resources of certain animal which is threatened or near extinction. This technology was then applied to the preservation of embryo, oocyte, ovary and testis. The application of intracytoplasmic sperm injection (ICSI for which sperm motility is unnecessary had supported the effort to create simplified method such as freeze-drying for sperm preservation. Due to the benefit of ICSI over the conventional in vitro fertilization (IVF the spermatozoon could be mechanically driven to pass through the zona pellucida and entering the cytoplasm of oocytes prior to fertilization. The freeze-drying method is an alternative method in sperm preservation which ignored the motility of sperm. The sperm resulted from this technique is in drying state, therefore, it might be stored in room temperature or in refrigerator. Many reports have claimed that freeze-dried sperm which is not motile but has an intact DNA was able to fertilize oocytes, even produced offspring in mouse.

  7. Effect of mixing time, freeze-drying and baking on phenolics, anthocyanins and antioxidant capacity of raspberry juice during processing of muffins.

    Science.gov (United States)

    Rosales-Soto, Maria U; Powers, Joseph R; Alldredge, J Richard

    2012-05-01

    Consumption of baked products constitutes an important part of a daily breakfast considering that people are continually grabbing meals on the go. Among baked products, muffins rank third in breakfast products and attract a broad range of consumers. Incorporation of red raspberry juice into muffins can add value to the product while preserving health benefits to the consumer. The purpose of this study was to evaluate the effect of mixing time, freeze-drying and baking on the phenolic and anthocyanin contents and antioxidant capacity of raspberry juice during the preparation of muffins. Freeze-drying of raspberry batters reduced their phenolic content and antioxidant capacity regardless of mixing time. Non-freeze-dried raspberry batter mixed for 5 min had the highest phenolic content (0.88 mg gallic acid equivalent g(-1) dry matter (DM)). Non-freeze-dried raspberry muffins had the highest antioxidant capacity (0.041 µmol Trolox equivalent g(-1) DM). Freeze-dried raspberry batters mixed for 5 and 10 min had the highest anthocyanin content (0.065 mg cyanidin-3-glucoside g(-1) DM). Baking reduced the anthocyanin content of both non-freeze-dried and freeze-dried raspberry muffins. Despite the reduction in valuable compounds, muffin is a vehicle for the delivery of these compounds. Copyright © 2012 Society of Chemical Industry.

  8. Optimization of the parameters of the daylily vacuum freeze-drying processing%黄花菜真空冷冻干燥工艺优化研究

    Institute of Scientific and Technical Information of China (English)

    许国宁; 吴素玲; 孙晓明; 张卫明

    2013-01-01

    为了提高黄花菜的干制品品质和优化真空冷冻干燥工艺,以还原糖含量、维生素C含量和复水比为评价指标,通过Design-Expert软件的Central Composite Design方法设计黄花菜干制的工艺,建立评价指标与物料装载量和加热板温度影响因素之间的回归数学模型.结合响应面分析方法对黄花菜真空冷冻干燥工艺进行优化,确定了真空冷冻干燥黄花莱的最佳工艺条件为:物料装载量为225g,加热板温度为50℃.%Taking the content of reducing sugar,the content of Vc and the rehydration as the evaluating indexes, to improve the qua ity of dried daylily and optimize the daylily vacuum freeze-drying process, central composite design of the Design-expert was used in the vacuum freeze-drying process of Daylily. Regression mathematical model between the index and impact factors was built. Central composite design was used to optimize experiments design and connect with the optimum method of response suraface methodology. The results showed that the optimal parameters of vacuum of freeze-drying process were as follows;material loadage was 225g and heating plate temperature was 50℃.

  9. Study on Freeze-drying Process of Ademetionine Butanedisulfonate%丁二磺酸腺苷蛋氨酸冻干工艺研究

    Institute of Scientific and Technical Information of China (English)

    刘桂祯; 劳瑞雄; 黄炯威; 宋光明

    2011-01-01

    为建立合适的丁二磺酸腺苷蛋氨酸冻干工艺,采用真空冷冻干燥法,对丁二磺酸腺苷蛋氨酸冻干条件如共晶点、装量、预冻程序、升华温度、升华真空度及解吸干燥温度等进行研究。结果显示:冻干工艺:装量为液面高度小于10 mm,预冻程序为预冻至-40℃,然后回温至-10℃,再降至-50℃,在真空度10~30 Pa,-25℃下升华,35℃解吸干燥。此工艺制备的丁二磺酸腺苷蛋氨酸外观好,产品质量符合国家标准。%A suitable freeze-drying process of ademetionine butanedisulfonate was established.Methods:The vacuum freeze-drying method was modified by the process such as liquid altitude in bottle,the eutectic point,pre-freeing process,sublimating temperature,sublimating vacuum,and temperature of desorption.The acceptable freeze-drying process was that liquid altitude was NMT 10 mm in bottle,pre-freeing process was that fell the temperature to-40 ℃,then back to-10 ℃,then fell to-50 ℃,sublimating temperature was-25 ℃,sublimating vacuum was 10~30 Pa,and temperature of desorption was 35 ℃.The lyophilized agent of ademetionine butanedisulfonate prepared by this process had look good and met the requirement of the SFDA.

  10. Survival rate of Saccharomyces boulardii adapted to a functional freeze-dried yoghurt, related to processing, storage and digestion by experimental Wistar rats

    Directory of Open Access Journals (Sweden)

    Eunice Tranquilino-Rodriguez

    2017-02-01

    Full Text Available Background: Saccharomycesboulardiiis a probiotic clinically effective inthe prevention and treatment of antibiotic induced diarrheain both children and adults, Clostridium difficile infections, inflammatory bowel disease, and other gastrointestinal disorders. However, the microorganisms need to survive the gastrointestinal transit and arrive to their action site alive in order to exert their beneficial effects. Microencapsulation is an alternative to improve the viability of probiotic in foods which can also survive in the gastrointestinal conditions. Freeze--drying is a method of dehydration that does not affect nutrients and bioactive compounds,such as probiotics contained in foods.All of them will increase the survival rate of S.boulardii.Purpose of this study:This study focused on formulae freeze-dried yogurt containing inulin, vegetable palm oil,and S.boulardii, both asfree cells and in microencapsulated form.Also,the effect of ampicillin associated S.boulardii. Methods. Yogurts were given to an “in vivo” digestion process, using male Wistar rats.The survival of S. boulardiiwas subsequently evaluated in colon and feces.For this study, six treatmentsof four of rats were used:i control rats ii rats fed with yogurt containing S. boulardiias free cells, iii rats fed with yogurt containing S. boulardiiinmicro-encapsulated form, iv control rats fed with penicillin,v rats fed with ampicillin plus yogurtcontaining S. boulardiias free cells, and vi rats fed with penicillin plus yogurt containing S. boulardiiin micro-encapsulated form. Results:The study demonstrated it was feasible to freeze-drythe S. boulardiiand incorporate it into a yogurtmade with skim milk,inulin, and unsaturated vegetable oil.The freeze-drying process not affected thesurvival of the S. boulardii(p<0.05. Microencapsulation increased the survival of S. boulardii on 1.77-Log CFU/g, and the presence of S. boulardii was only detected in colon and fecesof those rats which

  11. Computational analysis of fluid dynamics in pharmaceutical freeze-drying.

    Science.gov (United States)

    Alexeenko, Alina A; Ganguly, Arnab; Nail, Steven L

    2009-09-01

    Analysis of water vapor flows encountered in pharmaceutical freeze-drying systems, laboratory-scale and industrial, is presented based on the computational fluid dynamics (CFD) techniques. The flows under continuum gas conditions are analyzed using the solution of the Navier-Stokes equations whereas the rarefied flow solutions are obtained by the direct simulation Monte Carlo (DSMC) method for the Boltzmann equation. Examples of application of CFD techniques to laboratory-scale and industrial scale freeze-drying processes are discussed with an emphasis on the utility of CFD for improvement of design and experimental characterization of pharmaceutical freeze-drying hardware and processes. The current article presents a two-dimensional simulation of a laboratory scale dryer with an emphasis on the importance of drying conditions and hardware design on process control and a three-dimensional simulation of an industrial dryer containing a comparison of the obtained results with analytical viscous flow solutions. It was found that the presence of clean in place (CIP)/sterilize in place (SIP) piping in the duct lead to significant changes in the flow field characteristics. The simulation results for vapor flow rates in an industrial freeze-dryer have been compared to tunable diode laser absorption spectroscopy (TDLAS) and gravimetric measurements.

  12. A novel approach to sterile pharmaceutical freeze-drying.

    Science.gov (United States)

    Cherry, Christopher Lee Albert; Millward, Huw; Cooper, Rose; Landon, John

    2014-02-01

    A novel approach has been developed that enables sterile pharmaceutical products to be freeze-dried in the open laboratory without specialist facilities. The product is filled into vials, semi-stoppered and sealed inside one, followed by a second, sterilization pouch under class 100 conditions. The product is then freeze-dried in the laboratory where the vials are shelf-stoppered before being returned to class 100, unwrapped and crimped. The sterilization pouches increased the resistance to water vapor movement during sublimation, thereby increasing the sublimation time and product temperature. Ovine immunoglobulins were double wrapped and lyophilized (as above) adjusting the primary drying time and shelf temperature for increased product temperature and, therefore, prevention of collapse. Ovine immunoglobulin G formulations freeze-dried to ≤ 1.1% residual moisture with no effect on protein aggregation or biological activity. The process was simulated with tryptone soya broth and no growth of contaminating microbial cells was observed after incubation at 35 °C for 2 weeks. Although increasing lyophilization time, this approach offers significant plant and validation cost savings when sterile freeze-drying small numbers of vials thereby making the manufacture of treatments for neglected and orphan diseases more viable economically.

  13. Folic acid content in thermostabilized and freeze-dried space shuttle foods

    Science.gov (United States)

    Lane, H. W.; Nillen, J. L.; Kloeris, V. L.

    1995-01-01

    This study was designed to determine whether freeze-dried and thermostabilized foods on a space shuttle contain adequate folate and to investigate any effects of freeze-drying on folacin. Frozen vegetables were analyzed after three states of processing: thawed; cooked; and rehydrated. Thermostabilized items were analyzed as supplied with no further processing. Measurable folate decreased in some freeze-dried vegetables and increased in others. Folacin content of thermostabilized food items was comparable with published values. We concluded that although the folacin content of some freeze-dried foods was low, adequate folate is available from the shuttle menu to meet RDA guidelines.

  14. Drying a tuberculosis vaccine without freezing.

    Science.gov (United States)

    Wong, Yun-Ling; Sampson, Samantha; Germishuizen, Willem Andreas; Goonesekera, Sunali; Caponetti, Giovanni; Sadoff, Jerry; Bloom, Barry R; Edwards, David

    2007-02-20

    With the increasing incidence of tuberculosis and drug resistant disease in developing countries due to HIV/AIDS, there is a need for vaccines that are more effective than the present bacillus Calmette-Guérin (BCG) vaccine. We demonstrate that BCG vaccine can be dried without traditional freezing and maintained with remarkable refrigerated and room-temperature stability for months through spray drying. Studies with a model Mycobacterium (Mycobacterium smegmatis) revealed that by removing salts and cryoprotectant (e.g., glycerol) from bacterial suspensions, the significant osmotic pressures that are normally produced on bacterial membranes through droplet drying can be reduced sufficiently to minimize loss of viability on drying by up to 2 orders of magnitude. By placing the bacteria in a matrix of leucine, high-yield, free-flowing, "vial-fillable" powders of bacteria (including M. smegmatis and M. bovis BCG) can be produced. These powders show relatively minor losses of activity after maintenance at 4 degrees C and 25 degrees C up to and beyond 4 months. Comparisons with lyophilized material prepared both with the same formulation and with a commercial formulation reveal that the spray-dried BCG has better overall viability on drying.

  15. Spray freeze drying of YSZ nanopowder

    Science.gov (United States)

    Raghupathy, Bala P. C.; Binner, J. G. P.

    2012-07-01

    Spray freeze drying of yttria stabilised zirconia nanopowders with a primary particle size of 16 nm has been undertaken using different solids content starting suspensions, with the effect of the latter on the flowability and crushability of the granules being investigated. The flowability and fill density of the granules increased with an increase in the solid content of the starting suspension, whilst the crushability decreased. The powder flowability, measured using a Hall flowmeter and model shoe-die filling tests, showed that the flowability of otherwise poorly flowable nanopowders can be improved to match that of the commercial spray dried submicron powder. The 5.5 vol.% solid content based suspension yielded soft agglomerates whilst a 28 vol.% solid content suspension formed hard agglomerates on spray freeze drying; the granule relics were visible in the fracture surface of the die pressed green compact in the latter case. The increase in granule strength is explained by the reduction in inter-particle distance based on the theories developed by Rumpf and Kendall. The flaw sizes computed using the Kendall model are comparable with those seen in the micrographs of the granule. With an optimum solid content, it is possible to have a granulated nanopowder with reasonable flowability and compactability resulting in homogeneous green bodies with 54 % of theoretical density.

  16. Application of freeze-drying technology in manufacturing orally disintegrating films.

    Science.gov (United States)

    Liew, Kai Bin; Odeniyi, Michael Ayodele; Peh, Kok-Khiang

    2016-01-01

    Freeze drying technology has not been maximized and reported in manufacturing orally disintegrating films. The aim of this study was to explore the freeze drying technology in the formulation of sildenafil orally disintegrating films and compare the physical properties with heat-dried orally disintegrating film. Central composite design was used to investigate the effects of three factors, namely concentration of carbopol, wheat starch and polyethylene glycol 400 on the tensile strength and disintegration time of the film. Heat-dried films had higher tensile strength than films prepared using freeze-dried method. For folding endurance, freeze-dried films showed improved endurance than heat-dried films. Moreover, films prepared using freeze-dried methods were thicker and had faster disintegration time. Formulations with higher amount of carbopol and starch showed higher tensile strength and thickness whereas formulations with higher PEG 400 content showed better flexibility. Scanning electron microscopy showed that the freeze-dried films had more porous structure compared to the heat-dried film as a result of the release of water molecule from the frozen structure when it was subjected to freeze drying process. The sildenafil film was palatable. The dissolution profiles of freeze-dried and heat-dried films were similar to Viagra® with f2 of 51.04 and 65.98, respectively.

  17. Investigation of the stabilizing effects of hydroxyethyl cellulose on LDH during freeze drying and freeze thawing cycles.

    Science.gov (United States)

    Al-Hussein, Anas; Gieseler, Henning

    2015-01-01

    The objective of this study was to investigate both the cryoprotective and lyoprotective effects of the polymer hydroxyethyl cellulose (HEC) on the model protein lactate dehydrogenase (LDH) during freeze thawing and freeze drying cycles. The effect of annealing on both protein stability and the physical state of HEC was evaluated. HEC was used as a sole excipient in the protein formulations, and its stabilizing was compared to that of other excipients which are commonly used in freeze dried protein formulations. Furthermore, other quality aspects of the freeze dried samples containing solely HEC were investigated, such as, reconstitution time and product elegance. Protein stability was evaluated functionally by measuring the activity recovery of the model protein LDH. The physical state of HEC after freeze drying was investigated and compared to this of other studied solutes using differential scanning calorimetry and X-ray powder diffractometry. HEC showed superior cryoprotective effects on LDH during freeze thawing, and considerable lyoprotective effects during the freeze drying process. Annealing had limited influence on the stabilizing effect of HEC. The extensive reconstitution times of the HEC lyophilisates could be greatly improved by incorporation of the surfactant Tween 80 into the formulations prior to freeze drying.

  18. 微波真空冷冻干燥蜂蛹工艺的研究%Study on microwave vacuum freeze-drying process of Honeybee Pupae

    Institute of Scientific and Technical Information of China (English)

    平丽娟; 方晟; 毛建卫; 蔡成岗; 陈文斌

    2013-01-01

    Drying process of Honeybee Pupae by microwave vacuum freeze-drying and Optical fiber/infrared temperature measurement and control system were studied.The microwave intensities were set at 0.20,0.24,0.28, 0.32W/g and the results showed that the optimal dried product were got at 0.28W/g microwave intensity and the highest set temperature of 30℃,after drying 420min,the water content of the dried Honeybee Pupae was 2.84% , the final product was uniform with the original color and good taste flavor,and the electron micrograph showed that the product had sponge porous shape section,The dried Honeybee Pupae rehydrated 1.9 times of water in 20℃ water for Is,rehydrated effect was good,the SOD activity of the dried product slightly increased firstly and then decreased with level of 36.9U/mg protein after dried 420min,and the water content of the product was of 2.84%, Microwave vacuum freeze-drying decreased the drying time for 65% and tow viable microorganisms compared with the traditional vacuum freeze-drying method,while the SOD activity was almost at the same level,%采用微波真空冷冻干燥及光纤/红外温度测试控制等技术集成进行蜂蛹冻干中试工艺研究,用0.20、0.24、0.28、0.32W/g四个微波强度进行工艺优化,获得优化工艺参数为微波强度0.28W/g、最高解析温度30℃,微波冻干时间420min,最终产品水分含量为2.84%,产品品质好,无干瘪变形,保持蜂蛹原有色泽,电镜观察显示切面呈海绵多孔状,口味鲜美,于20℃水中复水1s,复水率达1.9倍,复水效果好,解析干燥过程中蜂蛹超氧化物歧化酶(SOD)活力呈现先略有增加后有所降低的趋势,蜂蛹冻于至水分含量为2.84%时,SOD活性为36.9U/mg prot,与真空冷冻干燥对比,所需干燥时间减少65%以上,并使存活微生物菌落数显著降低,SOD酶活力相近.

  19. 菠萝蜜真空冷冻干燥工艺的研究%The vacuum freeze-drying process of jackfruit

    Institute of Scientific and Technical Information of China (English)

    张容鹄; 万祝宁; 何艾; 谢辉; 窦志浩

    2012-01-01

    In this paper,vacuum freeze-drying method was applied to freezing-dry jackfruit.The eutectic point and consolute point were determined by electrical resistance method,freeze-drying curve was drew and the best freeze-drying procedure was definite by optimization.Then tests analyzed the influence factors on quality of freeze-drying jackfruit,such as pre-freezing method,different grade of maturity,slice wideth and soap method.Results indicated that the best freeze-drying procedure was:the first stage-20 ℃,5.5 h;the second-10 ℃,6 h;the third 20 ℃,4 h;the forth 30 ℃,4 h.Meanwhile,this showed little difference to the quality of products between two kinds of pre-freezing methods.Furthermore,in the addition of 90 percent maturity,4~7 mm incision wideth and 0.9% NaCl solution soaping,the products of freezing-dry was high of quality.Compared with the sale jackfruit products,the freeze-drying products had better quality.%采用真空冷冻干燥方法冻干菠萝蜜,电阻法测定菠萝蜜的共晶点和共熔点,绘制了冻干曲线,通过优化确定了最佳冻干程序。试验分析了预冻方式、浸泡方式、切割宽度对冻干菠萝蜜品质的影响。结果表明:最佳程序为第一段,-20℃,5.5h;第二段,-10℃,6h;第三段,20℃,4h;第四段,30℃,4h。进一步试验表明2种预冻方式对冻干产品影响不大,切条宽度为4~7mm,0.9%NaCl溶液浸泡后冻干得到产品品质好。冻干菠萝蜜与市售菠萝蜜脆片比较具有更好的品质。

  20. Freeze-drying in novel container system: Characterization of heat and mass transfer in glass syringes.

    Science.gov (United States)

    Patel, Sajal M; Pikal, Michael J

    2010-07-01

    This study is aimed at characterizing and understanding different modes of heat and mass transfer in glass syringes to develop a robust freeze-drying process. Two different holder systems were used to freeze-dry in syringes: an aluminum (Al) block and a plexiglass holder. The syringe heat transfer coefficient was characterized by a sublimation test using pure water. Mannitol and sucrose (5% w/v) were also freeze-dried, as model systems, in both the assemblies. Dry layer resistance was determined from manometric temperature measurement (MTM) and product temperature was measured using thermocouples, and was also determined from MTM. Further, freeze-drying process was also designed using Smart freeze-dryer to assess its application for freeze-drying in novel container systems. Heat and mass transfer in syringes were compared against the traditional container system (i.e., glass tubing vial). In the Al block, the heat transfer was via three modes: contact conduction, gas conduction, and radiation with gas conduction being the dominant mode of heat transfer. In the plexiglass holder, the heat transfer was mostly via radiation; convection was not involved. Also, MTM/Smart freeze-drying did work reasonably well for freeze-drying in syringes. When compared to tubing vials, product temperature decreases and hence drying time increases in syringes. (c) 2010 Wiley-Liss, Inc. and the American Pharmacists Association

  1. Heat and Mass Transfer Model in Freeze-Dried Medium

    Science.gov (United States)

    Alfat, Sayahdin; Purqon, Acep

    2017-07-01

    There are big problems in agriculture sector every year. One of the major problems is abundance of agricultural product during the peak of harvest season that is not matched by an increase in demand of agricultural product by consumers, this causes a wasted agricultural products. Alternative way was food preservation by freeze dried method. This method was already using heat transfer through conduction and convection to reduce water quality in the food. The main objective of this research was to design a model heat and mass transfer in freeze-dried medium. We had two steps in this research, the first step was design of medium as the heat injection site and the second was simulate heat and mass transfer of the product. During simulation process, we use physical property of some agriculture product. The result will show how temperature and moisture distribution every second. The method of research use finite element method (FEM) and will be illustrated in three dimensional.

  2. A Dynamic Design Space for Primary Drying During Batch Freeze-Drying

    DEFF Research Database (Denmark)

    Mortier, Séverine Thérèse F C; Van Bockstal, Pieter Jan; Nopens, Ingmar;

    2016-01-01

    model is used to determine the optimal values for the adaptable variables, hereby accounting for the uncertainty in all involved model parameters. A dynamic Design Space was constructed with a risk of failure acceptance level of 0.01%, i.e. a 'zero-failure' situation. Even for a risk of failure of 0......Biopharmaceutical products are emerging within the pharmaceutical industry. However, biopharmaceuticals are often unstable in aqueous solution. Freeze-drying (lyophilisation) is the preferred method to achieve a stable product with an increased shelf-life. During batch freeze-drying, there are only...... two adaptable process variables, i.e. the shelf temperature and the pressure in the drying chamber. The value of both should be optimized, preferably in a dynamic way, to minimise the primary drying time while respecting process and equipment constraints and ensuring end product quality. A mechanistic...

  3. Versatile Aerogel Fabrication by Freezing and Subsequent Freeze-Drying of Colloidal Nanoparticle Solutions.

    Science.gov (United States)

    Freytag, Axel; Sánchez-Paradinas, Sara; Naskar, Suraj; Wendt, Natalja; Colombo, Massimo; Pugliese, Giammarino; Poppe, Jan; Demirci, Cansunur; Kretschmer, Imme; Bahnemann, Detlef W; Behrens, Peter; Bigall, Nadja C

    2016-01-18

    A versatile method to fabricate self-supported aerogels of nanoparticle (NP) building blocks is presented. This approach is based on freezing colloidal NPs and subsequent freeze drying. This means that the colloidal NPs are directly transferred into dry aerogel-like monolithic superstructures without previous lyogelation as would be the case for conventional aerogel and cryogel fabrication methods. The assembly process, based on a physical concept, is highly versatile: cryogelation is applicable for noble metal, metal oxide, and semiconductor NPs, and no impact of the surface chemistry or NP shape on the resulting morphology is observed. Under optimized conditions the shape and volume of the liquid equal those of the resulting aerogels. Also, we show that thin and homogeneous films of the material can be obtained. Furthermore, the physical properties of the aerogels are discussed.

  4. Vacuum freeze-drying process of chestnut kernel%真空冷冻干燥板栗仁加工工艺研究

    Institute of Scientific and Technical Information of China (English)

    刘鹏飞; 周家华; 常虹; 马良; 张宇昊

    2011-01-01

    With fresh chestnut as raw materials,we studied the vacuum freeze-drying chestnut kernel processing technology.Results show that the color protection liquid composition for 0.2% ascorbic acid,0.3 % citric acid,0.1% ethylenediamine tetraacetate(EDTA) and 0.1% sodium chloride.Best temperature is 40 ℃.The best vacuum freeze-drying conditions is the material quantity 4.85 kg/m2,45 ℃ with 12 hours.Processed chestnut kernel water content is about 3%,taste sweet and crisp,chestnut original color,fragrance,taste to maintain good.%以新鲜板栗为原料,研究了真空冷冻干燥板栗仁的加工工艺。结果表明:板栗仁护色液组成为0.2%抗坏血酸、0.3%柠檬酸、0.1%乙二胺四乙酸(EDTA)和0.1%氯化钠;护色温度为40℃。最佳真空冷冻干燥条件是单位面积的物料量4.85kg/m2、隔板温度45℃、冻干时间为12h,制得的冷冻干燥板栗仁含水量为3%,口感香甜松脆,板栗原有色、香、味保持良好。

  5. Evaluation of spin freezing versus conventional freezing as part of a continuous pharmaceutical freeze-drying concept for unit doses.

    Science.gov (United States)

    De Meyer, L; Van Bockstal, P-J; Corver, J; Vervaet, C; Remon, J P; De Beer, T

    2015-12-30

    Spin-freezing as alternative freezing approach was evaluated as part of an innovative continuous pharmaceutical freeze-drying concept for unit doses. The aim of this paper was to compare the sublimation rate of spin-frozen vials versus traditionally frozen vials in a batch freeze-dryer, and its impact on total drying time. Five different formulations, each having a different dry cake resistance, were tested. After freezing, the traditionally frozen vials were placed on the shelves while the spin-frozen vials were placed in aluminum vial holders providing radial energy supply during drying. Different primary drying conditions and chamber pressures were evaluated. After 2h of primary drying, the amount of sublimed ice was determined in each vial. Each formulation was monitored in-line using NIR spectroscopy during drying to determine the sublimation endpoint and the influence of drying conditions upon total drying time. For all tested formulations and applied freeze-drying conditions, there was a significant higher sublimation rate in the spin-frozen vials. This can be explained by the larger product surface and the lower importance of product resistance because of the much thinner product layers in the spin frozen vials. The in-line NIR measurements allowed evaluating the influence of applied drying conditions on the drying trajectories.

  6. Freeze-Drying Makes Improved IPN And Semi-IPN Polymers

    Science.gov (United States)

    Pater, Ruth H.; Smith, Ricky E.; Razon, Ruperto T.; Hansen, Marion G.; Hsiung, Hahn J.; Soucek, Mark D.

    1993-01-01

    Novel process developed for production of interpenetrating polymer networks (IPN's) or semi-IPN's with greater fracture toughness and resistance to microcracks. Process controls degree of phase separation in IPN's. In experiment, IPN's and semi-IPN's formed by dissolving constituents in another common solvent in traditional method. Resins and composite materials produced were tested for both traditional and freeze-drying processes. Glass-transition temperatures and data from dynamic mechanical tests of freeze-dried IPN's and semi-IPN's demonstrated freeze-drying process provided much improved IPN's and semi-IPN's.

  7. Biochip-based instruments development for space exploration: influence of the antibody immobilization process on the biochip resistance to freeze-drying, temperature shifts and cosmic radiations

    Science.gov (United States)

    Coussot, G.; Moreau, T.; Faye, C.; Vigier, F.; Baqué, M.; Le Postollec, A.; Incerti, S.; Dobrijevic, M.; Vandenabeele-Trambouze, O.

    2017-04-01

    Due to the diversity of antibody (Ab)-based biochips chemistries available and the little knowledge about biochips resistance to space constraints, immobilization of Abs on the surface of the biochips dedicated to Solar System exploration is challenging. In the present paper, we have developed ten different biochip models including covalent or affinity immobilization with full-length Abs or Ab fragments. Ab immobilizations were carried out in oriented/non-oriented manner using commercial activated surfaces with N-hydroxysuccinic ester (NHS-surfaces) or homemade surfaces using three generations of dendrimers (dendrigraft of poly L-lysine (DGL) surfaces). The performances of the Ab -based surfaces were cross-compared on the following criteria: (i) analytical performances (expressed by both the surface density of immobilized Abs and the amount of antigens initially captured by the surface) and (ii) resistance of surfaces to preparation procedure (freeze-drying, storage) or spatial constraints (irradiation and temperature shifts) encountered during a space mission. The latter results have been expressed as percentage of surface binding capacity losses (or percentage of remaining active Abs). The highest amount of captured antigen was achieved with Ab surfaces having full-length Abs and DGL-surfaces that have much higher surface densities than commercial NHS-surface. After freeze-drying process, thermal shift and storage sample exposition, we found that more than 80% of surface binding sites remained active in this case. In addition, the resistance of Ab surfaces to irradiation with particles such as electron, carbon ions or protons depends not only on the chemistries (covalent/affinity linkages) and strategies (oriented/non-oriented) used to construct the biochip, but also on the type, energy and fluence of incident particles. Our results clearly indicate that full-length Ab immobilization on NHS-surfaces and DGL-surfaces should be preferred for potential use in

  8. Viability of Bifidobacterium Pseudocatenulatum G4 after Spray-Drying and Freeze-Drying

    Directory of Open Access Journals (Sweden)

    Stephenie Wong

    2010-04-01

    Full Text Available Viability of Bifidobacterium pseudocatenulatum G4 following spray-drying and freeze-drying in skim milk was evaluated. After spray-drying, the strain experienced over 99% loss in viability regardless of the air outlet temperature (75 and 85 °C and the heat-adaptation temperature (45 and 65 °C, 30 min. The use of heat-adaptation treatment to improve the thermotolerance of this strain was ineffective. On the other hand, the strain showed a superior survival at 71.65%–82.07% after freeze-drying. Viable populations of 9.319–9.487 log10 cfu/g were obtained when different combinations of skim milk and sugar were used as cryoprotectant. However, the addition of sugars did not result in increased survival during the freeze-drying process. Hence, 10% (w/v skim milk alone is recommended as a suitable protectant and drying medium for this strain. The residual moisture content obtained was 4.41% ± 0.44%.

  9. Optimization of the secondary drying step in freeze drying using TDLAS technology.

    Science.gov (United States)

    Schneid, Stefan C; Gieseler, Henning; Kessler, William J; Luthra, Suman A; Pikal, Michael J

    2011-03-01

    The secondary drying phase in freeze drying is mostly developed on a trial-and-error basis due to the lack of appropriate noninvasive process analyzers. This study describes for the first time the application of Tunable Diode Laser Absorption Spectroscopy, a spectroscopic and noninvasive sensor for monitoring secondary drying in laboratory-scale freeze drying with the overall purpose of targeting intermediate moisture contents in the product. Bovine serum albumin/sucrose mixtures were used as a model system to imitate high concentrated antibody formulations. First, the rate of water desorption during secondary drying at constant product temperatures (-22 °C, -10 °C, and 0 °C) was investigated for three different shelf temperatures. Residual moisture contents of sampled vials were determined by Karl Fischer titration. An equilibration step was implemented to ensure homogeneous distribution of moisture (within 1%) in all vials. The residual moisture revealed a linear relationship to the water desorption rate for different temperatures, allowing the evaluation of an anchor point from noninvasive flow rate measurements without removal of samples from the freeze dryer. The accuracy of mass flow integration from this anchor point was found to be about 0.5%. In a second step, the concept was successfully tested in a confirmation experiment. Here, good agreement was found for the initial moisture content (anchor point) and the subsequent monitoring and targeting of intermediate moisture contents. The present approach for monitoring secondary drying indicated great potential to find wider application in sterile operations on production scale in pharmaceutical freeze drying. © 2011 American Association of Pharmaceutical Scientists

  10. 微波与真空冷冻组合干燥加工佛手的工艺研究%Research on Processing Bergamot by Microwave Combined with Vacuum Freeze-Drying

    Institute of Scientific and Technical Information of China (English)

    章斌; 侯小桢; 饶强; 王泽彬

    2011-01-01

    [目的]探讨微波-真空冷冻组合干燥方式对佛手片加工的影响.[方法]以真空冷冻干燥总时间和成品复水率为主要指标,采用微波-真空冷冻组合干燥方式加工佛手片,并采用L9(33)正交试验优化工艺参数;同时,以成品Vc含量和精油含量为指标,对比不同干燥方法对佛手片品质的影响.[结果]相比单一的真空冷冻干燥,微波-真空冷冻组合干燥方法可明显缩短冻干总时间和提高成品复水率,该组合干燥的最优工艺参数为微波功率560 W,微波干燥时间2.5 min,物料厚度7mm,此条件下的冻干总时间为9.8h.[结论]微波-真空冷冻组合干燥相比微波干燥和真空冷冻干燥更能保证产品品质.%[Objective] To explore the effects of combined drying methods on processing of bergamot slices. [ Method ] Taking vacuum freeze-dr-ying time and rehydration rate as main indexes, processing bergamot slices by drying method of microwave combined with vacuum freeze-drying and optimum of parameters through L9(33) orthogonal experiments was studied; meanwhile, taking Vc content and essential oil content of bergamot product as indexes, the effect of quality by different drying methods was explored in this paper. [ Results ] Compared with vacuum freeze-drying, combined drying method can shorten freeze-drying time and improve rehydration rate significantly, under conditions of microwave 560 W, microwave processing time 2.5 min and material thickness 7 mm, the whole freeze-drying time is 9.8 h. [Conclusion] Combined drying method can improve products qualities better than microwave drying and vacuum freeze-drying.

  11. Determination of the drying and rehydration kinetics of freeze dried kiwi ( Actinidia deliciosa) slices

    Science.gov (United States)

    Ergün, Kadriye; Çalışkan, Gülşah; Dirim, Safiye Nur

    2016-12-01

    The aim of this study was to determine the drying and rehydration kinetics of freeze dried kiwi slices. Well-known thin layer drying models (Lewis, Page, Modified Page I, Henderson and Pabis, Modified Henderson and Pabis, Logarithmic, Midilli, Modified Midilli, Two-term, Two-term Exponential, Modified Two-term Exponential, and Wang and Singh) were fitted to the experimental data. A nonlinear regression analysis was used to evaluate the parameters of the selected models using statistical software SPSS 16.0. For the freeze drying process of the kiwi slices, the highest R2 value (0.997), and the lowest RMSE (0.018) as well as the χ2 (0.0004) values were obtained from the Two-term Exponential model. The effective moisture diffusivity (Deff) of the freeze dried kiwi slices was calculated with the Fick's diffusion model as 7.302 × 10-10 m2/s. The rehydration behavior was determined using distilled water at different solid-liquid ratios at room temperature (18 ± 1 °C) using Peleg's model. The kinetics of the total soluble solid loss was also determined.

  12. Determination of the drying and rehydration kinetics of freeze dried kiwi (Actinidia deliciosa) slices

    Science.gov (United States)

    Ergün, Kadriye; Çalışkan, Gülşah; Dirim, Safiye Nur

    2016-02-01

    The aim of this study was to determine the drying and rehydration kinetics of freeze dried kiwi slices. Well-known thin layer drying models (Lewis, Page, Modified Page I, Henderson and Pabis, Modified Henderson and Pabis, Logarithmic, Midilli, Modified Midilli, Two-term, Two-term Exponential, Modified Two-term Exponential, and Wang and Singh) were fitted to the experimental data. A nonlinear regression analysis was used to evaluate the parameters of the selected models using statistical software SPSS 16.0. For the freeze drying process of the kiwi slices, the highest R2 value (0.997), and the lowest RMSE (0.018) as well as the χ2 (0.0004) values were obtained from the Two-term Exponential model. The effective moisture diffusivity (Deff) of the freeze dried kiwi slices was calculated with the Fick's diffusion model as 7.302 × 10-10 m2/s. The rehydration behavior was determined using distilled water at different solid-liquid ratios at room temperature (18 ± 1 °C) using Peleg's model. The kinetics of the total soluble solid loss was also determined.

  13. Electrochemical properties of carbon aerogels with freeze - drying

    Science.gov (United States)

    Xu, Yuelong; Yan, Meifang; Liua, Zhenfa

    2017-09-01

    Carbon aerogels (CAs) were prepared via a sol–gel process by polymerization of phloroglucinol, resorcinol and formaldehyde using 2,4-dihydroxybenzoic acid as catalyst with freeze-drying. The electrochemical properties were characterized using cyclic voltammetry, galvanostatic charge–discharge measurements and electrochemical impedance spectroscopy (EIS). The specific capacitance of corresponding CAs was up to 131 F g‑1 and 105 F g‑1 at the density of 0.5 A g‑1 and 1.0 A g‑1, respectively.

  14. Calorimetric analysis of cryopreservation and freeze-drying formulations.

    Science.gov (United States)

    Sun, Wendell Q

    2015-01-01

    Differential scanning calorimetry (DSC) is a commonly used thermal analysis technique in cryopreservation and freeze-drying research. It has been used to investigate crystallization, eutectic formation, glass transition, devitrification, recrystallization, melting, polymorphism, molecular relaxation, phase separation, water transport, thermochemistry, and kinetics of complex reactions (e.g., protein denaturation). Such information can be used for the optimization of protective formulations and process protocols. This chapter gives an introduction to beginners who are less familiar with this technique. It covers the instrument and its basic principles, followed by a discussion of the methods as well as examples of specific applications.

  15. Microwave Enhanced Freeze Drying of Solid Waste Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The development of advanced methods for Microwave Enhanced Freeze Drying of Solid Waste (MEFDSW) is proposed. Methods for the recovery of relatively pure water as a...

  16. Microwave Enhanced Freeze Drying of Solid Waste Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of technology for Microwave Enhanced Freeze Drying of Solid Waste (MEFDSW) is proposed. The present state of the art for solid waste stabilization using...

  17. Development of freeze-dried miyeokguk, Korean seaweed soup, as space food sterilized by irradiation

    Science.gov (United States)

    Song, Beom-Seok; Park, Jin-Gyu; Kim, Jae-Hun; Choi, Jong-Il; Ahn, Dong-Hyun; Hao, Chen; Lee, Ju-Woon

    2012-08-01

    The purpose of this study was to evaluate microbial populations, Hunter's color values (L*, a*, b*) and the sensory quality of freeze-dried miyeokguk, Korean seaweed soup, in order to use it as space food. Microorganisms were not detected in non-irradiated freeze-dried miyeokguk within the detection limit of 1.00 log CFU/g. However, the microbial population in rehydrated miyeokguk was 7.01 log CFU/g after incubation at 35 °C for 48 h, indicating that freeze-dried miyeokguk was not sterilized by heat treatment during the preparation process. Bacteria in the freeze-dried miyeokguk were tentatively identified as Bacillus cereus, B. subtilis, Enterobacter hormaechei, and Ancinetobacter genomosp. using the 16S rDNA sequencing. In samples that were gamma-irradiated above 10 kGy, it was confirmed that all microorganisms were inactivated. Hunter's color values of the samples irradiated at doses less than 10 kGy were not significantly altered from their baseline appearance (p>0.05). Sensory evaluation showed that preference scores in all sensory properties decreased when freeze-dried miyeokguk was irradiated at doses greater than 10 kGy. Therefore, the results of this study suggest that gamma irradiation at 10 kGy is sufficient to sterilize freeze-dried miyeokguk without significant deterioration in the sensory quality, and thus, the freeze-dried and irradiated miyeokguk at 10 kGy fulfills the microbiological requirements as space food.

  18. Preliminary Study on Vacuum Freeze-drying Process of Lemon Piece%柠檬片真空冷冻干燥工艺初探

    Institute of Scientific and Technical Information of China (English)

    王玉玲; 李海滨

    2011-01-01

    以新鲜柠檬为试材,研究了柠檬片真空冷冻干燥的工艺条件.试验结果表明,冻干柠檬片的最佳工艺条件为:柠檬片切片厚度6.0mm,冻干时间10h,加热板温度60℃,冻干压力80Pa.此条件下加工的冻干柠檬片具有较好的感官品质及较高的柠檬酸及VC含量,褐变度较低,可保持新鲜柠檬原有的色、香、味和营养成分.%The technology of lemon vacuum freeze -drying was studied in this assay. It showed that the optimal conditions of vacuum freeze-drying were as follow: thickness of lemon piece was 6.0 mm, the time was 10 hours, the temperature of heating plate was 60℃ and freeze-drying pressure was 80 Pa. In this way, the lemon pieces were better in sensory quality, it kept high content of critic acids and vitamin C, and low lever of browning. The products which were produced by this condition was better in original color,fragrant character,flavor,shape and nutrition.

  19. Balancing mechanical strength with bioactivity in chitosan-calcium phosphate 3D microsphere scaffolds for bone tissue engineering: air- vs. freeze-drying processes.

    Science.gov (United States)

    Nguyen, D T; McCanless, J D; Mecwan, M M; Noblett, A P; Haggard, W O; Smith, R A; Bumgardner, J D

    2013-01-01

    The objective of this study was to evaluate the potential benefit of 3D composite scaffolds composed of chitosan and calcium phosphate for bone tissue engineering. Additionally, incorporation of mechanically weak lyophilized microspheres within those air-dried (AD) was considered for enhanced bioactivity. AD microsphere, alone, and air- and freeze-dried microsphere (FDAD) 3D scaffolds were evaluated in vitro using a 28-day osteogenic culture model with the Saos-2 cell line. Mechanical testing, quantitative microscopy, and lysozyme-driven enzymatic degradation of the scaffolds were also studied. FDAD scaffold showed a higher concentration (p mechanical strength was sacrificed through introduction of the less stiff, porous FD spheres.

  20. Study on Process Optimization of Freeze-dried Pleurotus ostreatus and its Effect on Quality%平菇冻干预处理工艺优化及其对品质的影响

    Institute of Scientific and Technical Information of China (English)

    孙亚男; 赵淑芳; 李文香; 胡欣蕾; 樊铭聪

    2015-01-01

    本文以平菇为试验材料,采用真空冷冻干燥技术进行平菇冻干。单因素试验探讨了烫漂温度、烫漂时间、麦芽糊精浸渍液浓度、预冻终温对冻干平菇品质影响,在此基础上,利用正交试验进一步优化平菇冻干预处理工艺,确定了最佳预处理工艺参数为:烫漂温度80益,烫漂时间90s,麦芽糊精浸渍液浓度2.5%,预冻终温-19益。此条件下可最大程度保持平菇原有的色泽与风味,提高冻干平菇的品质。%Based on the Pleurotus ostreatus as the experimental material, made freeze-dried Pleurotus ostreatus with vacuum freeze drying technology. The single factor and orthogonal experiment were used to study the four factors(blanching temperature, blanching time, the concentration of the impregnation liquid, precool final temperature)on the quality of freeze-dried sensory score, determining the best Pleurotus ostreatus freeze-drying process: blanching temperature 80℃, blanching time 90s, impregnation liquid concentration 2.5%, the precool final temperature -19℃. The process can maintain the Pleurotus ostreatus own color flavor in the greatest extent, and improve the quality of freeze-dried Pleurotus ostreatus .

  1. A comparison between spray drying and spray freeze drying to produce an influenza subunit vaccine powder for inhalation

    NARCIS (Netherlands)

    Saluja, V.; Amorij, J-P.; Kapteyn, J. C.; de Boer, A. H.; Frijlink, H. W.; Hinrichs, W. L. J.

    2010-01-01

    The aim of this study was to investigate two different processes to produce a stable influenza subunit vaccine powder for pulmonary immunization i.e. spray drying (SD) and spray freeze drying (SFD). The formulations were analyzed by proteolytic assay, single radial immunodiffusion assay (SRID), casc

  2. A comparison between spray drying and spray freeze drying to produce an influenza subunit vaccine powder for inhalation

    NARCIS (Netherlands)

    Saluja, V.; Amorij, J-P.; Kapteyn, J. C.; de Boer, A. H.; Frijlink, H. W.; Hinrichs, W. L. J.

    2010-01-01

    The aim of this study was to investigate two different processes to produce a stable influenza subunit vaccine powder for pulmonary immunization i.e. spray drying (SD) and spray freeze drying (SFD). The formulations were analyzed by proteolytic assay, single radial immunodiffusion assay (SRID),

  3. Modelling and simulation of a moving interface problem: freeze drying of black tea extract

    Science.gov (United States)

    Aydin, Ebubekir Sıddık; Yucel, Ozgun; Sadikoglu, Hasan

    2017-01-01

    The moving interface separates the material that is subjected to the freeze drying process as dried and frozen. Therefore, the accurate modeling the moving interface reduces the process time and energy consumption by improving the heat and mass transfer predictions during the process. To describe the dynamic behavior of the drying stages of the freeze-drying, a case study of brewed black tea extract in storage trays including moving interface was modeled that the heat and mass transfer equations were solved using orthogonal collocation method based on Jacobian polynomial approximation. Transport parameters and physical properties describing the freeze drying of black tea extract were evaluated by fitting the experimental data using Levenberg-Marquardt algorithm. Experimental results showed good agreement with the theoretical predictions.

  4. Modelling and simulation of a moving interface problem: freeze drying of black tea extract

    Science.gov (United States)

    Aydin, Ebubekir Sıddık; Yucel, Ozgun; Sadikoglu, Hasan

    2017-06-01

    The moving interface separates the material that is subjected to the freeze drying process as dried and frozen. Therefore, the accurate modeling the moving interface reduces the process time and energy consumption by improving the heat and mass transfer predictions during the process. To describe the dynamic behavior of the drying stages of the freeze-drying, a case study of brewed black tea extract in storage trays including moving interface was modeled that the heat and mass transfer equations were solved using orthogonal collocation method based on Jacobian polynomial approximation. Transport parameters and physical properties describing the freeze drying of black tea extract were evaluated by fitting the experimental data using Levenberg-Marquardt algorithm. Experimental results showed good agreement with the theoretical predictions.

  5. Model-based optimization of the primary drying step during freeze-drying

    DEFF Research Database (Denmark)

    Mortier, Séverine Thérèse F.C.; Van Bockstal, Pieter-Jan; Nopens, Ingmar;

    2015-01-01

    Since large molecules are considered the key driver for growth of the pharmaceutical industry, the focus of the pharmaceutical industry is shifting from small molecules to biopharmaceuticals: around 50% of the approved biopharmaceuticals are freeze-dried products. Therefore, freeze- drying is an ...

  6. Freeze-drying applied to radioactive source preparation.

    Science.gov (United States)

    de Sanoit, J; Leprince, B; Bobin, Ch; Bouchard, J

    2004-12-01

    In the framework of R&D studies for the improvement of radioactive source efficiencies prepared on thin films for 4pibeta-gamma coincidence counting, a comparative study on two drying methods has been undertaken in our laboratory (BNM-Laboratoire National Henri Becquerel, France). The standard method of evaporation at atmospheric pressure and a method based on freeze-drying using commercial equipment are compared. The preliminary results of this study obtained with 65Zn sources are presented and a significant improvement of the detection efficiencies to the electron emission for freeze-dried sources is shown. In the course of validation of this method, other radionuclides were studied and, up to now, the results confirm the better crystallization homogeneity achieved for freeze-dried sources.

  7. Improving the Quality of Freeze Dried Rice: Initial Evaluations

    Science.gov (United States)

    2015-05-01

    CRP. Improvement themes are product texture following rehydration, alternatives to plain FD rice, and fortification with vitamins and minerals. Phase...cm, placed in a –20 °C blast freezer and held overnight, then transferred to the production scale freeze dryer (Pilot Freeze Drying Plant , Budge... vitamins ) upon washing3 and cooking in excess water which is then discarded4, with these losses increasing when the rice was cooked with a greater

  8. Drying characteristics of pumpkin ( Cucurbita moschata) slices in convective and freeze dryer

    Science.gov (United States)

    Caliskan, Gulsah; Dirim, Safiye Nur

    2017-06-01

    This study was intended to determine the drying and rehydration kinetics of convective and freeze dried pumpkin slices (0.5 × 3.5 × 0.5 cm). A pilot scale tray drier (at 80 ± 2 °C inlet temperature, 1 m s-1 air velocity) and freeze drier (13.33 kPa absolute pressure, condenser temperature of -48 ± 2 °C) were used for the drying experiments. Drying curves were fitted to six well-known thin layer drying models. Nonlinear regression analysis was used to evaluate the parameters of the selected models by using statistical software SPSS 16.0 (SPSS Inc., USA). For the convective and freeze drying processes of pumpkin slices, the highest R2 values, and the lowest RMSE as well as χ2 values were obtained from Page model. The effective moisture diffusivity (Deff) of the convective and freeze dried pumpkin slices were obtained from the Fick's diffusion model, and they were found to be 2.233 × 10-7 and 3.040 × 10-9 m2s-1, respectively. Specific moisture extraction rate, moisture extraction rate, and specific energy consumption values were almost twice in freeze drying process. Depending on the results, moisture contents and water activity values of pumpkin slices were in acceptable limits for safe storage of products. The rehydration behaviour of [at 18 ± 2 and 100 ± 2 °C for 1:25, 1:50, 1:75, 1:100, and 1:125 solid:liquid ratios (w:w)] dried pumpkin slices was determined by Peleg's model with the highest R2. The highest total soluble solid loss of pumpkin slices was observed for the rehydration experiment which performed at 1:25 solid: liquid ratio (w:w). Rehydration ratio of freeze dried slices was found 2-3 times higher than convective dried slices.

  9. Drying characteristics of pumpkin (Cucurbita moschata) slices in convective and freeze dryer

    Science.gov (United States)

    Caliskan, Gulsah; Dirim, Safiye Nur

    2017-01-01

    This study was intended to determine the drying and rehydration kinetics of convective and freeze dried pumpkin slices (0.5 × 3.5 × 0.5 cm). A pilot scale tray drier (at 80 ± 2 °C inlet temperature, 1 m s-1 air velocity) and freeze drier (13.33 kPa absolute pressure, condenser temperature of -48 ± 2 °C) were used for the drying experiments. Drying curves were fitted to six well-known thin layer drying models. Nonlinear regression analysis was used to evaluate the parameters of the selected models by using statistical software SPSS 16.0 (SPSS Inc., USA). For the convective and freeze drying processes of pumpkin slices, the highest R2 values, and the lowest RMSE as well as χ2 values were obtained from Page model. The effective moisture diffusivity (Deff) of the convective and freeze dried pumpkin slices were obtained from the Fick's diffusion model, and they were found to be 2.233 × 10-7 and 3.040 × 10-9 m2s-1, respectively. Specific moisture extraction rate, moisture extraction rate, and specific energy consumption values were almost twice in freeze drying process. Depending on the results, moisture contents and water activity values of pumpkin slices were in acceptable limits for safe storage of products. The rehydration behaviour of [at 18 ± 2 and 100 ± 2 °C for 1:25, 1:50, 1:75, 1:100, and 1:125 solid:liquid ratios (w:w)] dried pumpkin slices was determined by Peleg's model with the highest R2. The highest total soluble solid loss of pumpkin slices was observed for the rehydration experiment which performed at 1:25 solid: liquid ratio (w:w). Rehydration ratio of freeze dried slices was found 2-3 times higher than convective dried slices.

  10. Freeze-drying of ampicillin solid lipid nanoparticles using mannitol as cryoprotectant

    Directory of Open Access Journals (Sweden)

    Faezeh Alihosseini

    2015-12-01

    Full Text Available abstract Solid lipid nanoparticles (SLNs are interesting colloidal drug-delivery systems, since they have all the advantages of the lipid and polymeric nanoparticles. Freeze-drying is a widely used process for improving the stability of SLNs. Cryoprotectants have been used to decrease SLN aggregations during freeze-drying. In this study Ampicillin was chosen to be loaded in a cholesterol carrier with nano size range. To support the stability of SLNs, freeze-drying was done using mannitol. Particle size, drug release profile and antibacterial effects were studied after freeze-drying in comparison with primary SLNs. Preparations with 5% mannitol showed the least particle size enlargement. The average particle size was 150 and 187 nm before and after freeze-drying, respectively. Freeze-drying did not affect the release profile of drug loaded nanopartilces. Also our study showed that lyophilization did not change the antimicrobial effect of ampicillin SLNs. DSC analysis showed probability of chemical interaction between ampicillin and cholesterol.

  11. Changes in non-volatile taste components of button mushroom (Agaricus bisporus) during different stages of freeze drying and freeze drying combined with microwave vacuum drying.

    Science.gov (United States)

    Pei, Fei; Shi, Ying; Gao, Xingyang; Wu, Fangning; Mariga, Alfred Mugambi; Yang, Wenjian; Zhao, Liyan; An, Xinxin; Xin, Zhihong; Yang, Fangmei; Hu, Qiuhui

    2014-12-15

    Button mushroom slices were dehydrated using freeze drying (FD) or FD combined with microwave vacuum drying (FMVD), and the non-volatile component profiles were studied. The results showed that the level of non-volatile components in button mushroom firstly increased during sublimation of FD/FMVD process and then fell during desorption in FD process and MVD in FMVD process. Compared to FD products, the contents of soluble sugars and polyols in FMVD products were relatively low, whereas the contents of total free amino acids were significantly higher, close to the level of fresh mushroom. However, there was no significant difference in the contents of 5'-nucleotides and organic acids between FD and FMVD products. The equivalent umami concentration (EUC) values for FD and FMVD products did not differ from fresh, indicating that both drying methods could effectively preserve MSG (monosodium glutamate)-like components in button mushroom. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Comparison between freeze and spray drying to obtain powder Rubrivivax gelatinosus biomass

    Directory of Open Access Journals (Sweden)

    Edson Francisco do Espírito Santo

    2013-03-01

    Full Text Available The use of colorants in products of animal origin is justified by the improvement in the color of foods since this attribute is considered a quality criterion. These additives can be produced using industrial effluents as substrates and appropriate organisms, such as Rubrivivax gelatinosus. Oxycarotenoids represent a class of carotenes responsible for the pigmentation of animals and vegetables. R. gelatinosus grows in fish industry effluent with the resulting production of a bacterial biomass containing oxycarotenoids. The purpose of this study was to compare the use of two drying processes - spray and freeze drying - to obtain powder biomass in terms of the process parameters (yield, productivity, and product recovery and the product characteristics (color, proximate composition, and oxycarotenoids. No difference was detected in the yield between these techniques, while productivity was higher using spray drying. Higher product recovery and moisture were achieved with freeze drying, while ash was higher with spray drying. The freeze dried biomass was redder, darker and less saturated than the spray dried biomass. No difference in oxycarotenoids was detected between the biomasses. Although it results in lower recovery rate, spray drying was faster and more productive, and it provided the same yield as freeze drying, which makes it the method of choice for obtaining R. gelatinosus biomass.

  13. Encapsulation of black carrot juice using spray and freeze drying.

    Science.gov (United States)

    Murali, S; Kar, Abhijit; Mohapatra, Debabandya; Kalia, Pritam

    2015-12-01

    Black carrot juice extracted using pectinase enzyme was encapsulated in three different carrier materials (maltodextrin 20DE, gum arabic and tapioca starch) using spray drying at four inlet temperatures (150, 175, 200 and 225 ℃) and freeze drying at a constant temperature of - 53 ℃ and vacuum of 0.22-0.11 mbar with the constant feed mixture. The products were analyzed for total anthocyanin content, antioxidant activity, water solubility index, encapsulation efficiency and total colour change. For both the drying methods followed in this study, maltodextrin 20DE as the carrier material has proven to be better in retaining maximum anthocyanin and antioxidant activity compared to gum arabic and tapioca starch. The best spray dried product, was obtained at 150 ℃. The most acceptable was the freeze dried product with maximum anthocyanin content, antioxidant activity, water solubility index, encapsulation efficiency and colour change.

  14. Experimental study on rehydration conditions of freeze-dried platelets

    Institute of Scientific and Technical Information of China (English)

    Ju-li FAN; Xian-guo XU; Shao-zhi ZHANG; Fa-ming ZHU; Guang-ming CHEN; Li-xing YAN

    2009-01-01

    A rehydration process for freeze-dried human platelets was studied on 1 ml of samples.The effects of prehydration duration,prehydration temperature,an rehydration solution on the recovery rate,mean platelet volume(MPV),and platelet distribution width(PDW)were investigated.The mass changes during the prehydration process were also studied.Three prehydration durations:0,1.5,and 3.5 h,and two rehydration solutions:platelet-poor plasma and phosphate-buffered saline(PBS),were tested.It was found that:(1)the prehydration was of significance;(2)1.5 h of prehydration had better effects than 3.5 h of prehydration;(3)as a rehydration solution,the platelet-poor plasma behaved better than the PBS.The impacts of prehydration duration and temperature on the results were studied.There was almost no difference between 35 and 37℃.Among all the prehydration durations tested,15,30,60,90,and 120 min,the best result was achieved with the time duration of 15 min.The weights of prehydrated platelets at the end of each test were measured and the water contents were calculated.Atier 15 min of prehydration,the water contents in the samples were about(4.8±0.01)%and(5.27±0.29)%(w/w)corresponding to the conditions of 35 and 37 ℃.respectively.These results will be helpful for further studies on the freeze-drying of mammalian cells.

  15. Effect of drying, freezing and storage of dried and frozen onion (Allium cepa L. on its pungency

    Directory of Open Access Journals (Sweden)

    Marcin Horbowicz

    2013-12-01

    Full Text Available The paper contains results of studies of drying and freezing effects, as well as storage of dried and frozen onion on its pungency. The effect of onion bulbs preparation on pungency was estimated as well. The pungency measurements were based on determination of pyruvate produced enzymatically by alliinase. Storage at 20°C of skinned onion decreases sligthly pungency, however three weeks storage at 0-2°C did not change it. Other results indicate that freezing at -25°C, and followed thawing led to large losses - reaching 75% of pungency found in the onion taken to the process. Storage of the frozen onion caused further decrease its pungency. Decrease of pungency during drying was depended on temperature of the process. Low drying temperature (40 and 50°C, 20 hours caused only 15-20% decline of pungency. Higher temperature drying (60°C resulted in 50% losses of onion pungency.

  16. 真空冷冻干燥过程神经网络模拟研究%Intelligent simulation of vacuum freeze-drying process by artificial neural network

    Institute of Scientific and Technical Information of China (English)

    郭树国; 王丽艳; 李成华

    2012-01-01

    Freeze drying is the best method to ensure the quality of dried products, but the high costs limit its application. BP neural network was used to simulate the vacuum freeze-drying process. After training of BP neural network with the results of ginseng slice in orthogonal experiment, the drying process conditions were predicted and optimized, and the simulation results fit well with the experiment datas. The results show that the BP neural network can simulate the vacuum freeze-drying process precisely.%真空冷冻干燥能够最好的保证干燥后产品质量,但干燥成本高已成为真空冷冻干燥技术大规模工业应用的技术瓶颈.因此利用BP神经网络理论对真空冷冻干燥过程进行了模拟研究,结果表明,BP神经网络能较精确的模拟真空冷冻干燥过程.采用人参切片干燥正交试验结果对BP神经网络进行训练后,对真空冷冻干燥工艺条件进行了预测和优化,预测值与试验实测值的相对误差较小,表明用BP神经网络理论模拟真空冷冻干燥过程具有较高的准确性.

  17. A case study on stress preconditioning of a Lactobacillus strain prior to freeze-drying.

    Science.gov (United States)

    Bergenholtz, Åsa Schoug; Wessman, Per; Wuttke, Anne; Håkansson, Sebastian

    2012-06-01

    Freeze-drying of bacterial cells with retained viability and activity after storage requires appropriate formulation, i.e. mixing of physiologically adapted cell populations with suitable protective agents, and control of the freeze-drying process. Product manufacturing may alter the clinical effects of probiotics and it is essential to identify and understand possible factor co-dependencies during manufacturing. The physical solid-state behavior of the formulation and the freeze-drying parameters are critical for bacterial survival and thus process optimization is important, independent of strain. However, the maximum yield achievable is also strain-specific and strain survival is governed by e.g. medium, cell type, physiological state, excipients used, and process. The use of preferred compatible solutes for cross-protection of Lactobacilli during industrial manufacturing may be a natural step to introduce robustness, but knowledge is lacking on how compatible solutes, such as betaine, influence formulation properties and cell survival. This study characterized betaine formulations, with and without sucrose, and tested these with the model lactic acid bacteria Lactobacillus coryniformis Si3. Betaine alone did not act as a lyo-protectant and thus betaine import prior to freeze-drying should be avoided. Differences in protective agents were analyzed by calorimetry, which proved to be a suitable tool for evaluating the characteristics of the freeze-dried end products.

  18. Freeze-dried bone in pulpotomy procedures in monkey.

    Science.gov (United States)

    Fadavi, S; Anderson, A W; Punwani, I C

    1989-01-01

    The purpose of this study was to evaluate the effect of freeze-dried bone on amputated pulps. Fifteen primary and one permanent monkey teeth were treated with freeze-dried bone. As the control group, another fifteen primary teeth were treated with calcium hydroxide and fifteen primary and one permanent teeth with formocresol. Four other primary teeth pulps were amputated and sealed with tin foil and IRM as controls. Twelve mandibular incisors were left intact. Histologically all but three teeth treated with human freeze-dried bone after three months showed a complete or partial calcific barrier directly below the amputation site. Normal appearing odontoblastic cells were noted below the calcific barrier. The apical third was vital with an occasional chronic inflammatory cell visible. The histological findings of teeth treated with calcium-hydroxide were very similar to freeze-dried bone. All but four teeth showed a complete calcific barrier at the amputation site. The odontoblastic cells were normal in appearance and the inflammatory cell reactions decreased from the middle portion toward the apical region. The histological evaluation of the formocresol-treated teeth was comparable with previously published studies.

  19. Effect of buffer systems and disaccharides concentration on Podoviridae coliphage stability during freeze drying and storage.

    Science.gov (United States)

    Dini, C; de Urraza, P J

    2013-06-01

    The aims of this study were to determine the stability of Podoviridae coliphage CA933P during lyophilization and storage in different media, and to establish similarities between the results obtained and those expected through mechanisms described for proteins stabilization during freeze-drying. PBS and SM buffer were assayed as lyophilization media. The effect of inorganic salts concentration as well as the addition of disaccharides on phage stability during freeze-drying and storage was also studied. The addition of low sucrose concentration (0.1 mol l⁻¹) to SM buffer stabilized phage during freezing and drying steps of the lyophilization process, but higher sugar concentrations were detrimental to phage stability during freeze-drying. Sucrose stabilized phage during storage for at least 120 days. The lyoprotective effect of low concentrations of disaccharides during the drying step of the lyophilization of proteins as well as the stabilization of the freeze-dried product in time correlated with the results obtained for phage CA933P.

  20. Convection in Drying and Freezing Ground

    CERN Document Server

    Faizal, Mir

    2012-01-01

    In this paper we analyse the drying of a soil composed of particles, water and solute impurities, and study the occurrence of convective instabilities during evaporation. We find that the main driving force for instability is the formation of a concentration gradient at the soil surface due to the evaporation of water. A similar phenomenon may occur during the thawing of frozen ground in Arctic regions.

  1. Heat transfer characteristics of current primary packaging systems for pharmaceutical freeze-drying.

    Science.gov (United States)

    Hibler, Susanne; Gieseler, Henning

    2012-11-01

    In the field of freeze-drying, the primary packaging material plays an essential role. Here, the packaging system not only contains and protects the drug product during storage and shipping, but it is also directly involved in the freeze-drying process itself. The heat transfer characteristics of the actual container system influence product temperature and therefore product homogeneity and quality as well as process performance. Consequently, knowledge of the container heat transfer characteristics is of vital importance for process optimization. It is the objective of this review article to provide a summary of research focused on heat transfer characteristics of different container systems for pharmaceutical freeze-drying. Besides the common tubing and molded glass vials and metal trays, more recent packaging solutions like polymer vials, LYOGUARD® trays, syringes, and blister packs are discussed. Recent developments in vial manufacturing are also taken into account.

  2. Aerosol delivery of nanoparticles in uniform mannitol carriers formulated by ultrasonic spray freeze drying.

    Science.gov (United States)

    D'Addio, Suzanne M; Chan, John Gar Yan; Kwok, Philip Chi Lip; Benson, Bryan R; Prud'homme, Robert K; Chan, Hak-Kim

    2013-11-01

    While most examples of nanoparticle therapeutics have involved parenteral or IV administration, pulmonary delivery is an attractive alternative, especially to target and treat local infections and diseases of the lungs. We describe a successful dry powder formulation which is capable of delivering nanoparticles to the lungs with good aerosolization properties, high loadings of nanoparticles, and limited irreversible aggregation. Aerosolizable mannitol carrier particles that encapsulate nanoparticles with dense PEG coatings were prepared by a combination of ultrasonic atomization and spray freeze drying. This process was contrasted to particle formation by conventional spray drying. Spray freeze drying a solution of nanoparticles and mannitol (2 wt% solids) resulted in particles with an average diameter of 21 ± 1.7 μm, regardless of the fraction of nanoparticles loaded (0-50% of total solids). Spray freeze dried (SFD) powders with a 50% nanoparticle loading had a fine particle fraction (FPF) of 60%. After formulation in a mannitol matrix, nanoparticles redispersed in water to nanoparticles evident upon rehydration. This study reveals the unique advantages of processing by ultrasonic spray freeze drying to produce aerosol dry powders with controlled properties for the delivery of therapeutic nanoparticles to the lungs.

  3. Freeze drying of red blood cells: the use of directional freezing and a new radio frequency lyophilization device.

    Science.gov (United States)

    Arav, Amir; Natan, Dity

    2012-08-01

    Red blood cell (RBC) units are administered routinely into patients expressing a wide range of acute and chronic conditions (e.g., anemia, traumatic bleeding, chronic diseases, and surgery). The modern blood banking system has been designed to answer this need and assure a continuous, high quality blood supply to patients. However, RBCs units can be stored under hypothermic conditions for only up to 42 days, which leads to periodic shortages. Cryopreservation can solve these shortages, but current freezing methods employ high glycerol concentrations, which need to be removed and the cells washed prior to transfusion, resulting in a long (more than 1 hour) and cumbersome washing step. Thus, frozen RBCs have limited use in acute and trauma situations. In addition, transportation of frozen samples is complicated and costly. Freeze drying (lyophilization) of RBCs has been suggested as a solution for these problems, since it will allow for a low weight sample to be stored at room temperature, but reaching this goal is not a simple task. We studied the effect of different solutions (IMT2 and IMT3) containing trehalose and antioxidants or trehalose and human serum albumin, respectively, on freezing/thawing and freeze drying of RBCs. In addition, we evaluated the effect of cells concentrations and cooling rates on the post thaw and post rehydration recoveries of the RBCs. Finally, we developed a new radio frequency (RF) lyophilization device for a more rapid and homogeneous sublimation process of the frozen RBCs samples. Recovery and free Hb were measured as well as oxygen association/dissociation and cell's deformability. We found that IMT3 (0.3 M trehalose and 10% HSA) solution that was directionally frozen at a rapid interface velocity of 1 mm/sec (resulting in a cooling rate of 150°C/min) yielded the best results (better than IMT2 solution and slow interface velocity). Freeze thawing gave 100% survival, while freeze drying followed by rehydration with 20% dextran-40k

  4. Preparation of Chitosan Nanocompositeswith a Macroporous Structure by Unidirectional Freezing and Subsequent Freeze-Drying

    Directory of Open Access Journals (Sweden)

    Inmaculada Aranaz

    2014-11-01

    Full Text Available Chitosan is the N-deacetylated derivative of chitin, a naturally abundant mucopolysaccharide that consists of 2-acetamido-2-deoxy-β-d-glucose through a β (1→4 linkage and is found in nature as the supporting material of crustaceans, insects, etc. Chitosan has been strongly recommended as a suitable functional material because of its excellent biocompatibility, biodegradability, non-toxicity, and adsorption properties. Boosting all these excellent properties to obtain unprecedented performances requires the core competences of materials chemists to design and develop novel processing strategies that ultimately allow tailoring the structure and/or the composition of the resulting chitosan-based materials. For instance, the preparation of macroporous materials is challenging in catalysis, biocatalysis and biomedicine, because the resulting materials will offer a desirable combination of high internal reactive surface area and straightforward molecular transport through broad “highways” leading to such a surface. Moreover, chitosan-based composites made of two or more distinct components will produce structural or functional properties not present in materials composed of one single component. Our group has been working lately on cryogenic processes based on the unidirectional freezing of water slurries and/or hydrogels, the subsequent freeze-drying of which produce macroporous materials with a well-patterned structure. We have applied this process to different gels and colloidal suspensions of inorganic, organic, and hybrid materials. In this review, we will describe the application of the process to chitosan solutions and gels typically containing a second component (e.g., metal and ceramic nanoparticles, or carbon nanotubes for the formation of chitosan nanocomposites with a macroporous structure. We will also discuss the role played by this tailored composition and structure in the ultimate performance of these materials.

  5. Novel Foams Based on Freeze-Dried Renewable Vital Wheat Gluten

    DEFF Research Database (Denmark)

    Blomfeldt, Thomas O.J.; Olsson, Richard T.; Menon, Mohan

    2010-01-01

    A new way of producing rigid or semi-rigid foams from vital wheat gluten using a freeze-drying process is reported. Water/gluten-based mixtures were frozen and freeze-dried. Different foam structures were obtained by varying the mixing process and wheat gluten concentration, or by adding glycerol...... or bacterial cellulose nanofibers. MIP revealed that the foams had mainly an open porosity peaking at 93%. The average pore diameter ranged between 20 and 73 µm; the sample with the highest wheat gluten concentration and no plasticizer had the smallest pores. Immersion tests with limonene revealed...

  6. Synergetic effect of freeze-drying and gamma irradiation on the mechanical properties of human cancellous bone.

    Science.gov (United States)

    Cornu, Olivier; Boquet, Jérome; Nonclercq, Olivier; Docquier, Pierre-Louis; Van Tomme, John; Delloye, Christian; Banse, Xavier

    2011-11-01

    Freeze-drying and irradiation are common process used by tissue banks to preserve and sterilize bone allografts. Freeze dried irradiated bone is known to be more brittle. Whether bone brittleness is due to irradiation alone, temperature during irradiation or to a synergetic effect of the freeze-drying-irradiation process was not yet assessed. Using a left-right femoral head symmetry model, 822 compression tests were performed to assess the influence of sequences of a 25 kGy irradiation with and without freeze-drying compared to the unprocessed counterpart. Irradiation of frozen bone did not cause any significant reduction in ultimate strength, stiffness and work to failure. The addition of the freeze-drying process before or after irradiation resulted in a mean drop of 35 and 31% in ultimate strength, 14 and 37% in stiffness and 46 and 37% in work to failure. Unlike irradiation at room temperature, irradiation under dry ice of solvent-detergent treated bone seemed to have no detrimental effect on mechanical properties of cancellous bone. Freeze-drying bone without irradiation had no influence on mechanical parameters, but the addition of irradiation to the freeze-drying step or the reverse sequence showed a detrimental effect and supports the idea of a negative synergetic effect of both procedures. These findings may have important implications for bone banking.

  7. Freeze-drying of drug-free and drug-loaded solid lipid nanoparticles (SLN).

    Science.gov (United States)

    Schwarz; Mehnert

    1997-11-28

    Solid lipid nanoparticles (SLN) of a quality acceptable for i.v. administration were freeze-dried. Dynasan 112 and Compritol ATO 888 were used as lipid matrices for the SLN, stabilisers were Lipoid S 75 and poloxamer 188, respectively. To study the protective effect of various types and concentrations of cryoprotectants (e.g. carbohydrates), freeze-thaw cycles were carried out as a pre-test. The sugar trehalose proved to be most effective in preventing particle growth during freezing and thawing and also in the freeze-drying process. Changes in particle size distribution during lyophilisation could be minimised by optimising the parameters of the lyophilisation process, i.e. freezing velocity and redispersion method. Lyophilised drug-free SLN could be reconstituted in a quality considered suitable for i.v. injection with regard to the size distribution. Loading with model drugs (tetracaine, etomidate) impairs the quality of reconstituted SLN. However, the lyophilisate quality is sufficient for formulations less critical to limited particle growth, e.g. freeze-dried SLN for oral administration.

  8. 药品真空冷冻干燥过程监控技术研究进展%Research progress in monitoring and control technology for pharmaceutical freeze-drying process

    Institute of Scientific and Technical Information of China (English)

    李俊奇; 李保国

    2015-01-01

    对药品冻干过程进行优化的关键是在保证药品质量不受损害的情况下尽量缩短干燥时间。因此,对冻干过程进行准确的监控是十分重要的,既要保证药品的温度保持在合理的范围内,对干燥结束时间进行准确地判断,同时又要对冻干过程压力和温度进行良好的控制以达到冻干过程的最优化。本文对近年来药品真空冷冻干燥过程监控技术的研究进展进行了综述,主要有基于动态参数估计法(DPE)的监控系统、基于卡尔曼滤波法的监测系统、露点法判断一次干燥结束点、模型预测控制法(MPC)。提出药品真空冷冻干燥监控技术的研究应着重于以下几点:考虑辐射、对流和导热3种传热方式在冻干传热过程中所占的比重,建立二维、三维冻干模型以更加精确地监测药品冻干过程的参数,在此基础上研究对加热隔板温度和冻干室压力的实时最优控制策略,以对药品冻干过程进行及时、有效地控制。%For the optimization of pharmaceutical freeze-drying process,the key is to shorten the drying time as much as possible and keep the good quality of the product. Therefore,it is very important to monitor and control the freeze-drying process precisely,i.e.,to keep the temperature of product within a reasonable range,judge the end point of drying time accurately,and a good control of chamber pressure and shelf temperature is needed to optimize the process. Research progress in pharmaceutical freeze-drying process monitoring and control technology in recent years is summarized in this paper,including monitoring system based on dynamic parameters estimation(DPE), monitoring system based on Kalman filter method,dew point method to judge the end point of primary drying,and model predictive control(MPC). The following points should be taken into account for further research on pharmaceutical freeze-drying monitoring and control

  9. Distribution of Vapor Pressure in the Vacuum Freeze-Drying Equipment

    Directory of Open Access Journals (Sweden)

    Shiwei Zhang

    2012-01-01

    Full Text Available In the big vacuum freeze-drying equipment, the drying rate of materials is uneven at different positions. This phenomenon can be explained by the uneven distribution of vapor pressure in chamber during the freeze-drying process. In this paper, a mathematical model is developed to describe the vapor flow in the passageways either between material plates and in the channel between plate groups. The distribution of vapor pressure along flow passageway is given. Two characteristic factors of passageways are defined to express the effects of structural and process parameters on vapor pressure distribution. The affecting factors and their actions are quantitatively discussed in detail. Two examples are calculated and analyzed. The analysis method and the conclusions are useful to estimate the difference of material drying rate at different parts in equipment and to direct the choice of structural and process parameters.

  10. Characteristics of Vacuum Freeze Drying with Utilization of Internal Cooling and Condenser Waste Heat for Sublimation

    Directory of Open Access Journals (Sweden)

    Muhammad Alhamid

    2013-09-01

    Full Text Available Vacuum freeze drying is an excellent drying method, but it is very energy-intensive because a relatively long drying time is required. This research investigates the utilization of condenser waste heat for sublimation as a way of accelerating the drying rate. In addition, it also investigates the effect of internal cooling combined with vacuum cooling in the pressure reduction process. Jelly fish tentacles were used as the specimen, with different configurations for condenser heat waste and internal cooling valve opening. The results show that heating with condenser heat waste can accelerate the drying rate up to 0.0035 kg/m2.s. In addition, pre-freezing by internal cooling prevents evaporation until the mass of the specimen is 0.47 g and promotes transition of the specimen into the solid phase.

  11. Characterization of freeze dried egg melange long stored after irradiation

    Science.gov (United States)

    Bakalivanov, Stefan; Tsvetkova, Eli; Bakalivanova, Todorka; Tsvetkov, Tsvetan; Kaloyanov, Nikolay; Grigorova, Stoyanka; Alexieva, Vanja

    2008-01-01

    During the 4-year period of storage at room temperature of the freeze-dried (control group) and the freeze-dried and gamma-irradiated (2.0 and 3.5 kGy) whole hen's egg mélange, no significant changes were found into the sensory and functional characteristics till the 28th month. The change in the number of SH groups was not unidirectional up to the 28th month and then it started to decrease in all investigated samples. During the entire period of investigation the amount of malondialdehyde in all three groups of egg mélange was considerably below the allowed limit for foodstuffs. The most significant fractions of the protein spectra showed a general tendency of decrease during the storage.

  12. Moisture sorption characteristics of freeze-dried human platelets

    Institute of Scientific and Technical Information of China (English)

    Meng-jie XU; Guang-ming CHEN; Ju-li FAN; Jin-hui LIU; Xian-guo XU; Shao-zhi ZHANG

    2011-01-01

    Freeze-drying is a promising method for a long-term storage of human platelets. The moisture sorption characteristics of freeze-dried human platelets (FDHPs) were studied in this paper. The moisture sorption isotherms of FDHPs and freeze-dried lyophilization buffer (FDLB) were measured at 4, 25, and 37 ℃. The experimental data were fitted to Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) equations. There were no significant statistical differences (P>0.05) between the sorption characteristics of FDHPs and FDLB at 4 and 25 ℃, while FDHPs absorbed more water at 37 ℃. The net isosteric heat of sorption was derived. The heat for FDHPs showed an abnormal negative value at low moisture contents when 25 and 37 ℃ data were used. Dynamic sorption experiments were carried out at 25 ℃ with environmental water activity controlled at 0.75, 0.85, and 0.90. The moisture diffusion coefficient was fitted to be 8.24x 10-12 m2/s when experimental data at initial time were used. These results would be helpful in choosing prehydration and storage condition for FDHPs.

  13. Technology Advances and Mechanistic Modelling in Freeze-drying and Dehydration of Food

    Directory of Open Access Journals (Sweden)

    Wanren Chen

    2015-08-01

    Full Text Available Aim of study is to introduce some advanced freeze-drying technology and mechanistic modelling in freeze-drying and dehydration of food, freeze-drying is based on the dehydration by sublimation of a frozen product, due to very low temperature, all the deterioration activity and microbiological activity are stopped and provide better quality to the final product. Meanwhile the main problems of the freeze-dried food were proposed and its prospect and outlook was also analyzed, expecting to obtain technical and theoretical support for the production of freeze-drying food.

  14. The Production of a Stable Infliximab Powder: The Evaluation of Spray and Freeze-Drying for Production

    Science.gov (United States)

    Kanojia, Gaurav; Have, Rimko ten; Bakker, Arjen; Wagner, Koen; Frijlink, Henderik W.; Kersten, Gideon F. A.; Amorij, Jean-Pierre

    2016-01-01

    In prospect of developing an oral dosage form of Infliximab, for treatment of Crohn’s disease and rheumatoid arthritis, freeze-drying (vial vs Lyoguard trays) and spray-drying were investigated as production method for stable powders. Dextran and inulin were used in combination with sucrose as stabilizing excipients. The drying processes did not affect Infliximab in these formulations, i.e. both the physical integrity and biological activity (TNF binding) were retained. Accelerated stability studies (1 month at 60°C) showed that the TNF binding ability of Infliximab was conserved in the freeze-dried formulations, whereas the liquid counterpart lost all TNF binding. After thermal treatment, the dried formulations showed some chemical modification of the IgG in the dextran-sucrose formulation, probably due to Maillard reaction products. This study indicates that, with the appropriate formulation, both spray-drying and freeze-drying may be useful for (bulk) powder production of Infliximab. PMID:27706175

  15. The Study on Technique of Making Freeze - dried Specimen of Mongolia Horse%The Study on Technique of Making Freeze-dried Specimen of Mongolia Horse

    Institute of Scientific and Technical Information of China (English)

    杨虹; 芒来

    2008-01-01

    冻干标本是在冷态条件下制作的,其方法为:迅速且完全地冷冻所选材料,待其干燥后进行加工.此方法比较简单且能真实的反应组织的位置、形状及它们的关系.以蒙古马为实验材料介绍了冻干标本工艺,以及如何保存维护冻干标本的方法.%The freeze - dried specimen is a kind of specimen made under cold conditions. The method is as follows: freeze the separated materials quickly and completely, then process the specimen after it has been dried. This kind of method is simple and can truly reflect the location and the shape of organs and also reflect their reciprocity. This study takes Mongolian home as the experimental animal to introduce the process. And then introduces the methods about how to preserve and protect freeze - dried specimen

  16. The impact of freeze-drying on microstructure and rehydration properties of carrot

    NARCIS (Netherlands)

    Voda, A.; Homan, N.; Witek, M.; Duijster, A.; Dalen, van G.; Sman, van der R.G.M.; Nijsse, J.; Vliet, van L.J.; As, van H.; Duynhoven, van J.P.M.

    2012-01-01

    The impact of freeze-drying, blanching and freezing rate pre-treatments on the microstructure and on the rehydration properties of winter carrots were studied by µCT, SEM, MRI and NMR techniques. The freezing rate determines the size of ice crystals being formed that leave pores upon drying. Their a

  17. Optimization of freeze-drying condition of amikacin solid lipid nanoparticles using D-optimal experimental design.

    Science.gov (United States)

    Varshosaz, Jaleh; Ghaffari, Solmaz; Khoshayand, Mohammad Reza; Atyabi, Fatemeh; Dehkordi, Abbas Jafarian; Kobarfard, Farzad

    2012-01-01

    Amikacin as an aminoglycoside antibiotic was chosen to be loaded in a cholesterol carrier with nanoparticle size and sustained release profile to increase the dose interval of amikacin and reduce side-effects. To support the stability of solid lipid nanoparticles (SLNs), freeze-drying was suggested. Factors affecting the freeze-drying process in the present study included the type and concentration of cryoprotectants. Pre-freezing temperature effects were also studied on particle size of SLNs of amikacin. In some preliminary experiments, important factors which influenced the particle size of SLNs after lyophilization were selected and a D-optimal design was applied to optimize the freeze-drying conditions in the production of SLNs with minimum particle size growth after freeze-drying. Zeta potential, DSC thermograms, release profiles and morphology of the optimized particles were studied before and after freeze-drying. Results showed sucrose changed the particle size of SLNs of amikacin from 149 ± 4 nm to 23.9 ± 16.7 nm; in that situation, the absolute value of zeta potential changed from 1 ± 0.7 mV to 13 ± 4 mV. The release profiles showed a sustained release behavior of the loaded drug that did not change significantly before and after freeze-drying, but a burst effect was seen after it in the first 2 h. DSC analysis showed chemical interaction between amikacin and cholesterol.

  18. Nasal dorsal augmentation with freeze-dried allograft bone.

    Science.gov (United States)

    Clark, Richard P; Wong, Granger; Johnson, Loche M; Hagge, Rosalie J; Ciminello, Frank; Lee, John; Stone, Kiki I; Clark, Isabel A

    2009-10-01

    Properly prepared freeze-dried bone has been used with impunity by orthopedic surgeons since 1992 without a single report of disease transmission. The aim of this study was to evaluate freeze-dried cortical allograft bone for nasal dorsal augmentation. Freeze-dried human cortical bone was obtained from DCI Donor Services, Nashville, Tennessee. Standards recommended by the American Association of Tissue Banks, the U.S. Food and Drug Administration, and the Centers for Disease Control and Prevention were followed. Objective evaluation of the persistence of graft volume was obtained by cephalometric radiography. Vascularization and incorporation of new bone elements within the grafts were demonstrated by using fluorine-18 sodium fluoride positron emission tomographic/computed tomographic scanning. The average persistence of projection in 18 patients was 87 percent at 6 months. Thereafter, 10 patients showed 100 percent maintenance of projection at 12 to 36 months. Vascularization and incorporation of new bone elements within the grafts were demonstrated by using fluorine-18 sodium fluoride positron emission tomographic/computed tomographic scanning in four patients. The initial loss of 13 percent of projection is most likely attributable to resolution of early surgical edema. The authors postulate that there are two pathways based on whether the recipient bed allows vascular access to the graft. The revascularization or inductive pathway involves stem cell conversion to eventual osteoblasts. The scar bed barrier or noninductive pathway involves the preservation of the graft as an unchanged alloimplant. This report is the first of a series that will include a 5-year and a 10-year follow-up.

  19. Effect of Glycerol, as Cryoprotectant in the Encapsulation and Freeze Drying of Microspheres Containing Probiotic Cells

    Directory of Open Access Journals (Sweden)

    Oana Lelia Pop

    2015-05-01

    Full Text Available It is reported that probiotics provide several health benefits as they help in maintaining a good balance and composition of intestinal flora, and increase the resistance against invasion of pathogens. Ensuring adequate dosages of probiotics at the time of consumption is a challenge, because several factors during processing and storage affect the viability of probiotic organisms. Major emphasis has been given to protect the microorganisms with the help of encapsulation technique, by addition of different protectants. In this study, probiotic cells (Bifidobacterium lactis 300B were entrapped in alginate/pullulan microspheres. In the encapsulation formula glycerol was used as cryoprotectant in the freeze drying process for long time storage. It was observed that the survival of Bifidobacterium lactis 300B when encapsulated without cryoprotectant was higher than the formula with glycerol in the fresh obtained microspheres. The addition of glycerol was in order to reduce the deep freezing and freeze drying damages. In the chosen formulations, glycerol did not proved protection for the entrapped probiotic cells in the freeze drying process, for which the use of glycerol as cryoprotectant for alginate/pullulan Bifidobacterium lactis 300B entrapment is not recommended.

  20. Physical Stability of Freeze-Dried Isomalt Diastereomer Mixtures

    DEFF Research Database (Denmark)

    Koskinen, Anna-Kaisa; Fraser-Miller, Sara J.; Bøtker, Johan P.

    2016-01-01

    of the diastereomer compositions showed signs of physical instability when stored in the highest relative humidity condition. The four different crystalline diastereomer mixtures showed specific identifiable solid state properties. Conclusions Isomalt was shown to be a suitable excipient for freeze-drying. Preferably...... a mixture of the diastereomers should be used, as the mixture containing only one of the isomers showed physical instability. A mixture containing a 1:1 ratio of the two diastereomers showed the best physical stability in the amorphous form....

  1. Crystallization and X-ray diffraction of spray-dried and freeze-dried amorphous lactose.

    Science.gov (United States)

    Haque, Md Kamrul; Roos, Yrjö H

    2005-02-07

    Crystallization of spray-dried and freeze-dried amorphous lactose over different relative vapor pressures (RVP) and storage times was studied. Crystallization was observed from increasing peak intensities in X-ray diffraction patterns. Lactose was crystallized in the samples stored at RVP of 44.1% and above in both types of dehydrated powders. The rate of crystallization increased with increasing RVP and storage time. Similar crystallization behavior of both spray-dried and freeze-dried lactose was observed. Lactose crystallized as alpha-lactose monohydrate, anhydrous beta-lactose, and the anhydrous form of alpha- and beta-lactose in a molar ratio of 5:3 and 4:1 in both spray-dried and freeze-dried forms. Peak intensities of X-ray diffraction patterns for anhydrous beta-lactose were decreased, and for alpha-lactose monohydrate increased with increasing storage RVP and time. The crystallization data were successfully modeled using Avrami equation at RVP of 54.5% and above. The crystallization data obtained is helpful in understanding and predicting storage stability of lactose-containing food and pharmaceutical products.

  2. Spray-freeze-dried dry powder inhalation of insulin-loaded liposomes for enhanced pulmonary delivery.

    Science.gov (United States)

    Bi, Ru; Shao, Wei; Wang, Qun; Zhang, Na

    2008-11-01

    Nowadays, growing attention has been paid to the pulmonary region as a target for the delivery of peptide and protein drugs, especially macromolecules with systemic effect like insulin, since the pulmonary route exhibits numerous benefits to be an alternative for repeated injection. Furthermore, encapsulation of insulin into liposomal carriers is an attractive way to increase drug retention time and control the drug release in the lung; however, its long-term stability during storage in the reservoir and the process of aerosolization might be suspected when practically applied. Thus, the aim of this study was to design and characterize dry powder inhalation of insulin-loaded liposomes prepared by novel spray-freeze-drying method for enhanced pulmonary delivery. Process variables such as compressed air pressure, pump speed, and concentration were optimized for parameters such as mean particle diameter, moisture content, and fine particle fraction of the produced powders. Influence of different kinds and amounts of lyoprotectants was also evaluated for the best preservation of the drug entrapped in the liposome bilayers after the dehydration-rehydration cycle. The in vivo study of intratracheal instillation of insulin-loaded liposomes to diabetic rats showed successful hypoglycemic effect with low blood glucose level and long-lasting period and a relative pharmacological bioavailability as high as 38.38% in the group of 8 IU/kg dosage.

  3. Effects of drying-wetting and freezing-thawing cycle on leachability of metallic elements in mine soils

    Science.gov (United States)

    Bang, H.; Kim, J.; Hyun, S.

    2016-12-01

    Mine leachate derived from contaminated mine sites with metallic elements can pose serious risks on human society and environment. Only labile fraction of metallic elements in mine soils is subject to leaching and movement by rainfall. Lability of metallic element in soil is a function of bond strengths between metal and soil surfaces, which is influenced by environmental condition (e.g., rainfall intensity, duration, temperature, etc.) The purpose of this study was to elucidate the effects of various climate conditions on the leaching patterns and lability of metallic elements in mine soils. To do this, two mine soils were sampled from two abandoned mine sites located in Korea. Leaching test were conducted using batch decant-refill method. Various climatic conditions were employed in leaching test such as (1) oven drying (40oC) - wetting cycles, (2) air drying (20oC) - wetting cycle, and (3) freezing (-40oC) - thawing cycles. Duration of drying and freezing were varied from 4 days to 2 weeks. Concentration of metallic elements, pH, Eh and concentration of dissolved iron and sulfate in leachate from each leaching process was measured. To identify the changes of labile fraction in mine soils after each of drying or freezing period, sequential extraction procedure (five fraction) was used to compare labile fraction (i.e., F1 + F2) of metallic elements. The concentration of metallic elements in mine leachate was increased after drying and freezing procedure. The amounts of released metallic element from mine soils was changed depending on their drying or freezing period. In addition, labile fraction of metallic elements in soil was also changed after drying and freezing. The changes in labile fraction after drying and freezing might be due to the increased soil surface area by pore water volume expansion. Further study is therefore needed to evaluate the impact of altered physical properties of soils such as hydration of soil surface area and shrinking by drying and

  4. Noncontact Infrared-Mediated Heat Transfer During Continuous Freeze-Drying of Unit Doses.

    Science.gov (United States)

    Van Bockstal, Pieter-Jan; De Meyer, Laurens; Corver, Jos; Vervaet, Chris; De Beer, Thomas

    2017-01-01

    Recently, an innovative continuous freeze-drying concept for unit doses was proposed, based on spinning the vials during freezing. An efficient heat transfer during drying is essential to continuously process these spin frozen vials. Therefore, the applicability of noncontact infrared (IR) radiation was examined. The impact of several process and formulation variables on the mass of sublimed ice after 15 min of primary drying (i.e., sublimation rate) and the total drying time was examined. Two experimental designs were performed in which electrical power to the IR heaters, distance between the IR heaters and the spin frozen vial, chamber pressure, product layer thickness, and 5 model formulations were included as factors. A near-infrared spectroscopy method was developed to determine the end point of primary and secondary drying. The sublimation rate was mainly influenced by the electrical power to the IR heaters and the distance between the IR heaters and the vial. The layer thickness had the largest effect on total drying time. The chamber pressure and the 5 model formulations had no significant impact on sublimation rate and total drying time, respectively. This study shows that IR radiation is suitable to provide the energy during the continuous processing of spin frozen vials.

  5. Evaluation of three methods for preservation of Azotobacter: freeze-drying, cryopreservation, and immobilization in dry polymers

    Directory of Open Access Journals (Sweden)

    Daniel Fernando Rojas Tapias

    2013-04-01

    Full Text Available Because the use of bacteria for biotechnological processes requires maintaining their viability and geneticstability, preserving them becomes essential. Here, we evaluated three preservation methods for A.chroococcum C26 and A. vinelandii C27; preservation methods: cryopreservation and immobilization in drypolymers for 60 days, and freeze-drying for 30. We evaluated their efficiency by counting viable cells andmeasuring nitrogen fixation activity. Additionally, we assessed the effect of three protective agents forfreeze-drying, three for cryopreservation, and four polymers. Freeze-drying proved the best technique tomaintain viability and activity, followed by immobilization and cryopreservation. Bacterial nitrogen fixingability remained unchanged using the freeze-drying method, and bacterial survival exceeded 80%; S/BSAwas the best protective agent. Immobilization maintained bacterial survival over 80%, but nitrogen fixationwas decreased by 20%. Lastly, cryopreservation resulted in a dramatic loss of viability for C26 (BSRapprox. 70%, whereas C27 was well preserved. Nitrogen fixation for both strains decreased regardless ofthe cryoprotective agent used (P < 0.05. In conclusion, the success of Azotobacter preservation methodsdepend on the technique, the protective agent, and the strain used. Our results also indicated that freezedryingusing S/BSA is the best technique to preserve bacteria of this genus.

  6. The impact of vacuum freeze-drying on collagen sponges after gas plasma sterilization.

    Science.gov (United States)

    Markowicz, M; Koellensperger, E; Steffens, G C M; Frentz, M; Schrage, N; Pallua, N

    2006-01-01

    The sterilization of porous collagen sponges remains a challenging procedure. Gamma irradiation denatures collagen, resulting in dramatic changes to its structure. Ethylene oxide leaves toxic residues requiring weeks to evaporate. This study investigated the impact on cell behavior of gas plasma treatment when combined with vacuum freeze-drying. The goal of this procedure is to eliminate the molecules of hydrogen peroxide remaining after the sterilization process, together with their decomposition products, from the scaffolds. These molecules hinder the immediate use of the porous designs. Collagen and EDC/NHS-heparinized collagen scaffolds were sterilized with gas plasma. H2O2 released by the collagen specimens was measured by peroxidase test both immediately and also 1 week after the plasma treatment. Further measurements were done 24, 36, 48 and 72 h after vacuum freeze-drying. The activity of these scaffolds was further evaluated in relation to the proliferation, migration and differentiation of human umbilical vein endothelial cells (HUVECs). Both immediately after exposure to gas plasma and also 1 week later, the collagen designs contained significantly higher concentrations of H2O2 than scaffolds having also undergone vacuum freeze-drying. This procedure achieved faster decontamination of the remaining H2O2. Following vacuum freeze-drying, sponges already allowed HUVEC proliferation after 48 h, but in non-lyophilized specimens after gas plasma treatment alone, cell death occurred as early as only 1 week later. These data highlight the advantages of carrying out vacuum freeze-drying following gas plasma sterilization. The results show the substantial impact of sterilization of porous materials made for tissue engineering.

  7. The freezing step in lyophilization: physico-chemical fundamentals, freezing methods and consequences on process performance and quality attributes of biopharmaceuticals.

    Science.gov (United States)

    Kasper, Julia Christina; Friess, Wolfgang

    2011-06-01

    Lyophilization is a common, but cost-intensive, drying process to achieve protein formulations with long-term stability. In the past, typical process optimization has focused on the drying steps and the freezing step was rather ignored. However, the freezing step is an equally important step in lyophilization, as it impacts both process performance and product quality. While simple in concept, the freezing step is presumably the most complex step in lyophilization. Therefore, in order to get a more comprehensive understanding of the processes that occur during freezing, the physico-chemical fundamentals of freezing are first summarized. The available techniques that can be used to manipulate or directly control the freezing process in lyophilization are also reviewed. In addition, the consequences of the freezing step on quality attributes, such as sample morphology, physical state of the product, residual moisture content, reconstitution time, and performance of the primary and secondary drying phase, are discussed. A special focus is given to the impact of the freezing process on protein stability. This review aims to provide the reader with an awareness of not only the importance but also the complexity of the freezing step in lyophilization and its impact on quality attributes of biopharmaceuticals and process performance. With a deeper understanding of freezing and the possibility to directly control or at least manipulate the freezing behavior, more efficient lyophilization cycles can be developed, and the quality and stability of lyophilized biopharmaceuticals can be improved. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Ice crystal damage in freeze-dried articular cartilage studied by scanning electron microscopy.

    Science.gov (United States)

    Draenert, Y; Draenert, K

    1982-01-01

    The aim of preparing specimens at very low temperatures is to maintain biological tissue in its natural state. The problems which arise are: 1) obtaining the highest possible cooling rate when freezing the tissue; 2) preventing melting with recrystallization during the drying process; and 3) preventing the dried specimens from water vapor contamination. Biological tissue is prepared in a cooling chain by freezing the samples in a supercooled nitrogen bath, breaking the specimens in the frozen state, sputtering the fracture surfaces in a vacuum on the cooling stage of a special device and then transferring the specimens under vacuum to the SEM where they are studied on a cooling stage. They have smooth surfaces, with the liquid and solid phases present simultaneously, and no artefacts. Any shifts or deformations which may occur within the structure cannot yet be determined. Freeze-drying quenched specimens at various temperatures (-140 degrees to -60 degrees C) taking the dynamics of vapor pressure into consideration shows that sublimation, the melting processes with recrystallization and the resulting damage to the structures occur simultaneously during the drying process. The destruction of the tissue is inversely proportional to the ratio of sublimation to melting.

  9. Technological Development of Brewing in Domestic Refrigerator Using Freeze-Dried Raw Materials

    Directory of Open Access Journals (Sweden)

    Angelika-Ioanna Gialleli

    2017-01-01

    Full Text Available Development of a novel directly marketable beer brewed at low temperature in a domestic refrigerator combined with yeast immobilization technology is presented in this study. Separately, freeze-dried wort and immobilized cells of the cryotolerant yeast strain Saccharomyces cerevisiae AXAZ-1 on tubular cellulose were used in low-temperature fermentation (2, 5 and 7 °C. The positive eff ect of tubular cellulose during low-temperature brewing was examined, revealing that freeze-dried immobilized yeast cells on tubular cellulose signifi cantly reduced the fermentation rates in contrast to freeze-dried free cells, although they are recommended for home-made beer production. Immobilization also enhanced the yeast resistance at low-temperature fermentation, reducing the minimum brewing temperature value from 5 to 2 °C. In the case of high-quality beer production, the eff ect of temperature and initial sugar concentration on the fermentation kinetics were assessed. Sensory enrichment of the produced beer was confi rmed by the analysis of the fi nal products, revealing a low diacetyl concentration, together with improved polyphenol content, aroma profi le and clarity. The proposed process for beer production in a domestic refrigerator can easily be commercialized and applied by dissolving the content of two separate packages in tap water; one package containing dried wort and the other dried immobilized cells on tubular cellulose suspended in tap water.

  10. Physical characterization of pentamidine isethionate during freeze-drying-relevance to development of stable lyophilized product.

    Science.gov (United States)

    Sundaramurthi, Prakash; Burcusa, Michael R; Suryanarayanan, Raj

    2012-05-01

    The purpose of this study was to perform physical characterization of pentamidine isethionate (PI) in frozen and freeze-dried systems and to monitor the phase behavior during all the stages of freeze-drying. Frozen aqueous PI solutions as well as the final lyophiles were characterized by differential scanning calorimetry and X-ray diffractometry. The effect of cosolutes, cosolvents, and processing conditions on the PI crystallization behavior during freeze-drying was evaluated. In frozen aqueous solutions, irrespective of the cooling rate and the initial solute concentration, PI readily crystallized as a trihydrate (C(19) H(24) N(4) O(2) ·3H(2) O). It dehydrated to a poorly crystalline anhydrate upon drying at 100 mTorr. The presence of a readily crystallizing cosolute or an organic cosolvent did not influence the physical form of PI in the final lyophile. On the contrary, even in the absence of cosolutes and cosolvents, the crystalline trihydrate was retained when the chamber pressure was increased to 500 mTorr. By altering the drying conditions, it was possible to obtain either a crystalline trihydrate or a poorly crystalline anhydrate. The stability of PI is dependent on its physical form and only the amorphous PI undergoes discoloration. The PI stability can be enhanced by retaining it in a crystalline state in the lyophile.

  11. Model of Mass and Heat Transfer during Vacuum Freeze-Drying for Cornea

    Directory of Open Access Journals (Sweden)

    Zou Huifen

    2012-01-01

    Full Text Available Cornea is the important apparatus of organism, which has complex cell structure. Heat and mass transfer and thermal parameters during vacuum freeze-drying of keeping corneal activity are studied. The freeze-drying cornea experiments were operated in the homemade vacuum freeze dryer. Pressure of the freeze-drying box was about 50 Pa and temperature was about −10°C by controlled, and operating like this could guarantee survival ratio of the corneal endothelium over the grafting normal. Theory analyzing of corneal freeze-drying, mathematical model of describing heat and mass transfer during vacuum freeze-drying of cornea was established. The analogy computation for the freeze-drying of cornea was made by using finite-element computational software. When pressure of the freeze-drying box was about 50 Pa and temperature was about −10°C, time of double-side drying was 170 min. In this paper, a moving-grid finite-element method was used. The sublimation interface was tracked continuously. The finite-element mesh is moved continuously such that the interface position always coincides with an element node. Computational precision was guaranteed. The computational results were agreed with the experimental results. It proved that the mathematical model was reasonable. The finite-element software is adapted for calculating the heat and mass transfer of corneal freeze-drying.

  12. Optimization of freeze drying conditions for purified pectinase from mango (Mangifera indica cv. Chokanan) peel

    National Research Council Canada - National Science Library

    Mehrnoush, Amid; Mustafa, Shuhaimi; Yazid, Abdul Manap Mohd

    2012-01-01

    Response surface methodology (RSM) along with central composite design (CCD) was applied to optimize the freeze drying conditions for purified pectinase from mango (Mangifera indica cv. Chokanan) peel...

  13. Process of Freeze-dried Ready to Eat Sea Cucumber Health Soup%冻干速溶即食海参汤的加工工艺研究

    Institute of Scientific and Technical Information of China (English)

    李银塔

    2013-01-01

    Discussed the impacts of modified starch and freeze-dried sea cucumber on the quality of the sea cucumber soup ingredients by vacuum freeze-drying technique. We had determined the making process and optimum technology parameter of instant sea cucumber soup through orthogonal experiment as follows: corn starch and potato starch mixed in ratio of 1∶1, which dosage is 1%. The best pore size of preparing frangipani is 0.1 cm×0.4 cm;Freeze drying after soaking and slicing is the best way to deal with sea cucumber. Mixed starch 0.65 g, medlar 1 g, salt 1 g, American ginseng 0.3 g, the sea cucumber 8 g, nori 20 g, frangipani 35 g, this recipe can obtain well instant sea cucumber soup. Product 10 g with water 200 g which above 90 ℃, we will obtain delicious instant sea cucumber soup after soaking 1min.%采用真空冷冻干燥技术,探讨变性淀粉、冻干海参及海参汤配料对质量的影响,通过正交试验确定了速溶海参养生汤的制作工艺及最佳工艺参数:玉米淀粉和马铃薯淀粉按1∶1(质量比)混合,混合淀粉用量是1%;制备鸡蛋花最佳孔径为0.1 cm×0.4 cm;海参最佳处理方式为泡发后切片进行冷冻干燥。混合淀粉0.65 g、枸杞子1 g、西洋参0.3 g、盐度1 g、海参8 g、紫菜20 g、鸡蛋花35 g组成的配方,可获得良好冲调性的速溶海参汤。10 g本产品,加温度90℃以上水200 g,浸泡1 min可获得色、香、味俱佳的速溶海参汤。

  14. Suitability of a Freeze Dried Product as a Vehicle for Vitamin Fortification of Military Ration Packs: A Preliminary Study

    Science.gov (United States)

    2011-01-01

    loaded into the freeze dryer and dried over an eight hour period. The freeze dried product was removed from the freeze dryer and transferred to...plastic bags (one bag per treatment). While in the bag the pieces of freeze dried product were manually broken and tumbled to mix. The bags were placed

  15. Effect of protective agents and previous acclimation on ethanol resistance of frozen and freeze-dried Lactobacillus plantarum strains.

    Science.gov (United States)

    Bravo-Ferrada, Bárbara Mercedes; Brizuela, Natalia; Gerbino, Esteban; Gómez-Zavaglia, Andrea; Semorile, Liliana; Tymczyszyn, E Elizabeth

    2015-12-01

    The aim of this work was to study the protective effect of sucrose, trehalose and glutamate during freezing and freeze-drying of three oenological Lactobacillus plantarum strains previously acclimated in the presence of ethanol. The efficiency of protective agents was assessed by analyses of membrane integrity and bacterial cultivability in a synthetic wine after the preservation processes. No significant differences in the cultivability, with respect to the controls cells, were observed after freezing at -80 °C and -20 °C, and pre-acclimated cells were more resistant to freeze-drying than non-acclimated ones. The results of multiparametric flow cytometry showed a significant level of membrane damage after freeze-drying in two of the three strains. The cultivability was determined after incubation in wine-like medium containing 13 or 14% v/v ethanol at 21 °C for 24 h and the results were interpreted using principal component analysis (PCA). Acclimation was the most important factor for preservation, increasing the bacterial resistance to ethanol after freezing and freeze-drying. Freeze-drying was the most drastic method of preservation, followed by freezing at -20 °C. The increase of ethanol concentration from 6 to 10% v/v in the acclimation medium improved the recovery of two of the three strains. In turn, the increase of ethanol content in the synthetic wine led to a dramatic decrease of viable cells in the three strains investigated. The results of this study indicate that a successful inoculation of dehydrated L. plantarum in wine depends not only on the use of protective agents, but also on the cell acclimation process prior to preservation, and on the ethanol content of wine.

  16. Freeze-drying as a preserving preparation technique for in vitro testing of human skin.

    Science.gov (United States)

    Franzen, Lutz; Vidlářová, Lucie; Kostka, Karl-Heinz; Schaefer, Ulrich F; Windbergs, Maike

    2013-01-01

    In vitro testing of drugs with excised human skin is a valuable prerequisite for clinical studies. However, the analysis of excised human skin presents several obstacles. Ongoing drug diffusion, microbial growth and changes in hydration state influence the results of drug penetration studies. In this work, we evaluate freeze-drying as a preserving preparation method for skin samples to overcome these obstacles. We analyse excised human skin before and after freeze-drying and compare these results with human skin in vivo. Based on comprehensive thermal and spectroscopic analysis, we demonstrate comparability to in vivo conditions and exclude significant changes within the skin samples due to freeze-drying. Furthermore, we show that freeze-drying after skin incubation with drugs prevents growth of drug crystals on the skin surface due to drying effects. In conclusion, we introduce freeze-drying as a preserving preparation technique for in vitro testing of human skin.

  17. Mimicking the quasi-random assembly of protein fibers in the dermis by freeze-drying method.

    Science.gov (United States)

    Ghaleh, Hakimeh; Abbasi, Farhang; Alizadeh, Mina; Khoshfetrat, Ali Baradar

    2015-04-01

    Freeze-drying is extensively used for fabrication of porous materials in tissue engineering and biomedical applications, due to its versatility and use of no toxic solvent. However, it has some significant drawbacks. Conventional freeze-drying technique leads to the production of heterogeneous porous structures with side orientated columnar pores. As the top and bottom surfaces of the sample are not in contact with similar environments, different rates of heat transfer in the surfaces and the temperature gradient across the sample establish the preferential direction of heat transfer. To achieve a scaffold with a desirable microstructure for skin tissue engineering, freeze-drying method was modified by controlling the rate of cooling and regulation of heat transfer across the sample during the freezing step. It could create a homogeneous porous structure with more equiaxed non-oriented pores. Freezing the polymeric solution in the aluminum mold enhanced pore interconnectivity relative to the polystyrene mold. Recrystallization process was discussed how to influence the mean pore size of the scaffold when the final freezing temperature varied. Higher final freezing temperature can easily provide the energy required for the recrystallization process, which lead to enlarged ice crystals and resulting pores.

  18. Effects of ultrasonic pretreatments on quality, energy consumption and sterilization of barley grass in freeze drying.

    Science.gov (United States)

    Cao, Xiaohuang; Zhang, Min; Mujumdar, Arun S; Zhong, Qifeng; Wang, Zhushang

    2018-01-01

    Barley grass is a plant resource for rehabilitation therapy. Its processing requires retaining nutrition well for rehabilitation cure of consumers. To meet the aim as well as low energy consumption and microbiological safety of products, ultrasonic treatments (UT) were applied to bathing materials at different power levels (10, 30, 45, 60W/L) for 10mins. After treatments, the bathed barley grass (100g) was freeze-dried under vacuum -0.09MPa with fixed power of 2W/g. Parameters of color, microbial colony, energy consumption, glass transition temperature, moisture content, water activity, taste substances, contents of flavonoid and chlorophyll were determined after drying. In contrast with no treatment case, UT (45W/L) decreased drying time by 14% and decreased energy consumption by 19%; UT (60W/L) decreased total microbial colonies by 33%. Also, UT (30W/L) yielded contents of flavonoid (9.2/kg) and chlorophyll (10.5g/kg) of dried sample; UT power (10W/L) yielded the highest L(∗)(51.5) and the lowest a(∗)(-9.3) value. Simultaneously, UT leads to a higher glass transition temperature (Tg), lower water activity and produces less sourness and bitterness of dried products. Ultra-sonication is an alternative to improve quality, flavor and energy consumption of barley grass in freeze drying. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Physico-chemical and rheological properties of gelatinized/freeze-dried cereal starches

    Science.gov (United States)

    Krystyjan, Magdalena; Ciesielski, Wojciech; Gumul, Dorota; Buksa, Krzysztof; Ziobro, Rafał; Sikora, Marek

    2017-07-01

    The influence of gelatinization and freeze-drying process on the physico-chemical and rheological properties of cereal starches was evaluated, and it was observed that modified starches revealed an increased water binding capacity and solubility when compared to dry starches, while exhibiting the same amylose and fat contents. The molecular weights of starches decreased after modification which resulted in the lower viscosity of dissolved modified samples in comparison to native starch pastes. As it was observed by scanning electron microscopy modified starches were characterized by an expanded surface, a uniform structure and high porosity.

  20. Intracellular trehalose improves the survival of human red blood cells by freeze-drying

    Institute of Scientific and Technical Information of China (English)

    HE Hui; LIU Baolin; HUA Zezhao; LI Chuan; WU Zhengzheng

    2007-01-01

    Freeze-drying of human red blood cells has a potential important application for blood transfusion.The aim of this study was to investigate the effects ofintracellular trehalose on the survival of red blood cells after freeze-drying and rehydration.Fresh red blood cells were incubated in trehalose solutions of various concentrations at 37℃ for 7 h following freeze-drying.Polyvinylpyrrolidone,Trehalose,sodium citrate,and human serum albumin were used as extracellular protective agents for the freeze-drying of red blood cells.The results indicated that the intracellular trehalose concentration was increased with increasing concentration of extracellular trehalose solution,and the maximum concen tration of intracellular trehalose reached 35 mmol/L.The viability of freeze-dried red blood cells increased with the increment of intracellular trehalose concentration.

  1. Density dependent mechanical properties and structures of a freeze dried biopharmaceutical excipient--sucrose.

    Science.gov (United States)

    Devi, Sharmila; Williams, Daryl R

    2014-10-01

    Knowledge of the mechanical behaviour of freeze dried biopharmaceutical products is essential for designing of products with physical robustness that will not to crack, crumble or collapse during processing or transportation. The compressive mechanical deformation behaviour for freeze-dried sucrose cakes has been experimentally studied from a relative density (ρf/ρs) of 0.01-0.30 using a novel in-vial indentation test. Cakes exhibited more open like structures at lower densities and more closed structures at higher densities with some faces being present at all densities, as confirmed by SEM. The reduced elastic modulus Ef/Es=0.0044(ρf/ρs)(1) for all cake densities, indicating that face stretching was the dominant deformation mode assuming Gibson and Ashby's closed cell model. This linear scaling for the reduced elastic modulus is in line with various theoretical treatments based on tetrakaidecahedral cells and other experimental studies. Consistently, the wall thickness to cell diameter ratio scaled ρf/ρs with a power constant of 1.05. The maximum crushing stress was given by σmax=3800(ρf/ρs)(1.48) which agrees with a strut bending failure stress, assuming Gibson and Ashby's open cell model. Overall, the freeze dried cakes behaved as neither classic closed cell nor open cell materials, with their compressive elastic moduli reflecting a closed cell elastic response whilst their failure stresses reflecting an open cell failure mode. It was concluded that the mechanical response of freeze dried cellular materials depends upon their complex cellular structures and morphologies, and they cannot be rationalised using simple limiting case models of open or closed cell solids.

  2. Freeze Drying Improves the Shelf-Life of Conductive Polymer Modified Neural Electrodes

    Directory of Open Access Journals (Sweden)

    Himadri S. Mandal

    2015-08-01

    Full Text Available Coating microelectrodes with conductive polymer is widely recognized to decrease impedance and improve performance of implantable neural devices during recording and stimulation. A concern for wide-spread use of this approach is shelf-life, i.e., the electrochemical stability of the coated microelectrodes prior to use. In this work, we investigated the possibility of using the freeze-drying process in order to retain the native low impedance state and, thereby, improve the shelf-life of conductive polymer poly(3,4-ethylenedioxythiophene (PEDOT-PSS modified neural electrodes. Control PEDOT-PSS coated microelectrodes demonstrated a significant increase in impedance at 1 kHz after 41–50 days of room temperature storage. Based on equivalent circuit modeling derived from electrochemical impedance spectroscopy, this increase in impedance could be largely attributed to a decrease in the interfacial capacitance consistent with a collapse and closing of the porous structure of the polymeric coating. Time-dependent electrochemical impedance measurements revealed higher stability of the freeze-dried coated microelectrodes compared to the controls, such that impedance values after 41–50 days appeared to be indistinguishable from the initial levels. This suggests that freeze drying PEDOT-PSS coated microelectrodes correlates with enhanced electrochemical stability during shelf storage.

  3. Application of plackett-burman design in screening freeze drying cryoprotectants for Lactobacillus bulgaricus

    Directory of Open Access Journals (Sweden)

    Guowei SHU

    2015-08-01

    Full Text Available Lactobacillus bulgaricus is the bacteria commonly used in probiotic dairy product, including yogurt and cheese. The bacteria may be stored for long periods of time if it is freeze-dried. The cryoprotectant mixture for L. bulgaricus was optimized during the process of freeze-drying using a Plackett-Burman design and the steepest ascent test. In our initial tests, the cell survival rate and the number of viable cells were associated with the type of cyroprotectant used. Therefore, our optimization protocol focused on increasing survival rate. Substances that previously had a protective effect during freeze-drying were investigated, for example: sucrose, lactose, skim milk powder, sodium bicarbonate, sodium glutamate, magnesium sulfate, sodium ascorbate, yeast extract, vitamin B2, and phosphate buffer. We determined that the optimum cryoprotectant composition for L. bulgaricus consists of 28.0 g/100 mL skim milk powder, 24.0 g/100 mL lactose and 4.8 g/100 mL sodium ascorbate. The optimized cryoprotectant provides a 63.25% cell survival rate.

  4. New freeze-drying method for LiFePO 4 synthesis

    Science.gov (United States)

    Palomares, Verónica; Goñi, Aintzane; Muro, Izaskun Gil de; de Meatza, Iratxe; Bengoechea, Miguel; Miguel, Oscar; Rojo, Teófilo

    The freeze-drying method is proposed as an effective synthesis process for the obtaining of LiFePO 4/C composites. The citric acid is used as a complexing agent and carbon source. After the low temperature annealing, the freeze-dried solution leads to a homogeneous carbon covered LiFePO 4 sample. The chemical characterization of the material included ICP and elemental analysis, infrared spectroscopy, X-ray diffraction, magnetic measurements and thermal analysis. SEM and TEM microscopies indicate an aggregate morphology with tiny particles of lithium iron phosphate inside a carbon matrix. Impedance spectroscopy showed a 8.0 × 10 -7 S cm -1 conductivity value. Cyclic voltammetry graphics displayed the two peaks corresponding to the Fe(II)/Fe(III) reaction and demonstrated the good reversibility of the material. The specific capacity value obtained at C/40 rate was 164 mAh g -1, with a slight decrease on greater C-rates reaching 146 mAh g -1 at C/1. The capacity retention study has evidenced good properties, with retention over 97% of the maximum values in the first 50 cycles, which allows an effective performance of the freeze-dried sample as cathodic material in lithium-ion batteries.

  5. Size control in production and freeze-drying of poly-ε-caprolactone nanoparticles.

    Science.gov (United States)

    Zelenková, Tereza; Fissore, Davide; Marchisio, Daniele L; Barresi, Antonello A

    2014-06-01

    This work is focused on the control of poly-ε-caprolactone nanoparticle characteristics, notably size and size distribution, in both the production and preservation (by using freeze-drying) stages. Nanoparticles were obtained by employing the solvent displacement method in a confined impinging jets mixer. The effect of several operating conditions, namely, initial polymer concentration and solvent-to-antisolvent flow rate ratio, and the influence of postprocessing conditions, such as final dilution and solvent evaporation, on nanoparticle characteristics was investigated. Further addition of antisolvent (water) after preparation was demonstrated to be effective in obtaining stable nanoparticles, that is, avoiding aggregation that would result in larger particles. On the contrary, solvent (acetone) evaporation was shown to have a small effect on the final nanoparticle characteristics. Eventually, freeze-drying of the solutions containing nanoparticles, after solvent evaporation, was also investigated. To ensure maximum nanoparticles stability, lyoprotectants (e.g., sucrose and mannitol) and steric stabilizers (e.g., Cremophor EL and Poloxamer 388) had to be added to the suspensions. The efficacy of the selected lyoprotectants, in the presence (or absence) of steric stabilizers, and in various concentrations, to avoid particle aggregation during the freeze-drying process was investigated, thus pointing to the optimal formulation.

  6. Jet-vortex spray freeze drying for the production of inhalable lyophilisate powders.

    Science.gov (United States)

    Wanning, Stefan; Süverkrüp, Richard; Lamprecht, Alf

    2017-01-01

    Spray-freeze-dried powders were suggested for nasal, epidermal (needle-free injection) or pulmonary application of proteins, peptides or nucleic acids. In spray-freeze-drying processes an aqueous solution is atomized into a refrigerant medium and subsequently dried by sublimation. Droplet-stream generators produce a fast stream of monodisperse droplets, where droplets are subject to collisions and therefore the initial monodispersity is lost and droplets increase in diameter, which reduces their suitability for pulmonary application. In jet-vortex-freezing, a droplet-stream is injected into a vortex of cold process gas to prevent droplet collisions. Both the injection position of the droplet-stream and the velocity of the cold gas vortex have an impact on the size distributions of the resulting powders. A model solution containing mannitol (1.5%m/V) and maltodextrin (1.5%m/V) was sprayed at 5 droplet-stream positions at distances between 1mm and 30mm from the gas jet nozzle and 5 gas velocities (0.8-6.8m/s) at a process temperature of -100°C. Mean geometric diameters of the highly porous particles (bulk density: 0.012±0.007g/cm3) ranged between 55±4 and 98±4μm. Evaluation of the aerodynamic properties by Next-Generation-Impactor (NGI) analysis showed that all powders had high emitted doses (98±1%) and fine-particle fractions ranged between 4±1% and 21±2%. It was shown that jet-vortex freezing is a suitable method for the reproducible production of lyophilized powders with excellent dispersibility in air, which has a high potential for nasal and pulmonary drug delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Rational design of an influenza subunit vaccine powder with sugar glass technology : preventing conformational changes of haemagglutinin during freezing and freeze-drying

    NARCIS (Netherlands)

    Amorij, J-P; Meulenaar, J; Hinrichs, W L J; Stegmann, T; Huckriede, A; Coenen, F; Frijlink, H W

    2007-01-01

    The development of a stable influenza subunit vaccine in the dry state was investigated. The influence of various carbohydrates, buffer types and freezing rates on the integrity of haemagglutinin after freeze-thawing or freeze-drying was investigated with a range of analytical and immunological meth

  8. Rational design of an influenza subunit vaccine powder with sugar glass technology : preventing conformational changes of haemagglutinin during freezing and freeze-drying

    NARCIS (Netherlands)

    Amorij, J-P; Meulenaar, J; Hinrichs, W L J; Stegmann, T; Huckriede, A; Coenen, F; Frijlink, H W

    2007-01-01

    The development of a stable influenza subunit vaccine in the dry state was investigated. The influence of various carbohydrates, buffer types and freezing rates on the integrity of haemagglutinin after freeze-thawing or freeze-drying was investigated with a range of analytical and immunological

  9. Influence of Stress Treatments on the Resistance of Lactococcus lactis to Freezing and Freeze-Drying

    OpenAIRE

    Lin, Chan

    1998-01-01

    This study investigated the effect of cold, heat, or osmotic shock treatment on the resistance of L. lactis subsp. cremoris MM160 and MM310 and Lactococcus lactis subsp. lactis MM210 and FG2 cheese starter bacteria to freezing and freeze-drying. The ability to withstand freezing at -60°C for 24 h was variable among lactococci, but resistance to this treatment was significantly improved (P < 0.05) in most strains by a 2-h cold shock at l0°C or a 25-min heat shock at 39°C (L. lactis subsp. crem...

  10. Freezing and thawing of processed meat in an industrial freezing tunnel

    Directory of Open Access Journals (Sweden)

    Glaucio Antonio Marini

    2014-04-01

    Full Text Available Freezing is a commonly used preservation method in the meat industry. The understanding of the product behavior during the freezing process can assist in a better process management and quality control. This work reports the study of freezing and thawing of three types of processed meat in order to determine process parameters in an industrial forced‑air freezing tunnel at ‑30oC. Chicken sausages (frankfurter type, mortadela (bologna type and mechanically deboned chicken meat (MDCM were studied. Products were placed in several layers in corrugated cardboard boxes (CCB for sausages and mortadela. MDCM was placed in a nylon box. Temperature sensors were inserted in the products and the freezing and thawing curves were obtained. Freezing curves were used to determine the freezing time (tf, initial freezing point (Tf and final freezing point (T’m. Products placed in different layers in the CCB had significantly different freezing times, being the higher rates for products placed in more external layers than internal ones. The external layers of product were subjected to heat transfer by convection showing its importance to decrease freezing time. The results strongly suggest that products placed in different layers could have distinct quality properties and also play a key role in the freezing process efficiency.

  11. Novel budesonide particles for dry powder inhalation (DPI) prepared using a microfluidic reactor coupled with ultrasonic spray freeze drying.

    Science.gov (United States)

    Saboti, Denis; Maver, Uroš; Chan, Hak-Kim; Planinšek, Odon

    2017-03-09

    Budesonide is a potent active pharmaceutical ingredient, often administered using respiratory devices such as metered dose inhalers (MDI), nebulizers and dry powder inhalers (DPI). Inhalable drug particles are conventionally produced by crystallization followed by milling. This approach tends to generate partially amorphous materials that require post-processing to improve the formulations' stability. Other methods involve homogenization or precipitation and often require the use of stabilizers, mostly surfactants. The purpose of this study was therefore to develop a novel method for preparation of fine budesonide particles using a microfluidic reactor coupled with ultrasonic spray freeze drying, and hence avoiding the need of additional homogenization or stabilizer use. A T-junction microfluidic reactor was employed to produce particle suspension (using an ethanol-water, methanol-water and an acetone-water system), which was directly fed into an ultrasonic atomization probe, followed by direct feeding to liquid nitrogen. Freeze drying was the final preparation step. The result were fine crystalline budesonide powders which, when blended with lactose and dispersed in an Aerolizer at 100 L/min, generated fine particle fraction in the range 47.6±2.8% to 54.9±1.8%, thus exhibiting a good aerosol performance. Subsequent sample analysis confirmed the suitability of the developed method to produce inhalable drug particles without additional homogenization or stabilizers. The developed method provides a viable solution for particle isolation in microfluidics in general.

  12. Adverse effect of cake collapse on the functional integrity of freeze-dried bull spermatozoa.

    Science.gov (United States)

    Hara, Hiromasa; Tagiri, Miho; Hwang, In-Sul; Takahashi, Masato; Hirabayashi, Masumi; Hochi, Shinichi

    2014-06-01

    Under optimal freeze-drying conditions, solutions exhibit a cake-like porous structure. However, if the solution temperature is higher than the glass transition temperature of the maximally freeze-concentrated phase (Tg') during drying phase, the glassy matrix undergoes viscous flow, resulting in cake collapse. The purpose of the present study was to investigate the effect of cake collapse on the integrity of freeze-dried bull spermatozoa. In a preliminary experiment, factors affecting the Tg' of conventional EGTA buffer (consisting of Tris-HCl, EGTA and NaCl) were investigated in order to establish the main experimental protocol because EGTA buffer Tg' was too low (-45.0°C) to suppress collapse. Modification of the EGTA buffer composition by complete removal of NaCl and addition of trehalose (mEGTA buffer) resulted in an increase of Tg' up to -27.7°C. In the main experiment, blastocyst yields after ooplasmic injection of freeze-dried sperm preserved in collapsed cakes (drying temperature: 0 or -15°C) were significantly lower than those of sperm preserved in non-collapsed cake (drying temperature: -30°C). In conclusion, freeze-dried cake collapse may be undesirable for maintaining sperm functions to support embryonic development, and can be inhibited by controlling both Tg' of freeze-drying buffer and temperature during the drying phase.

  13. Formation of highly porous aerosol particles by atmospheric freeze-drying in ice clouds.

    Science.gov (United States)

    Adler, Gabriela; Koop, Thomas; Haspel, Carynelisa; Taraniuk, Ilya; Moise, Tamar; Koren, Ilan; Heiblum, Reuven H; Rudich, Yinon

    2013-12-17

    The cycling of atmospheric aerosols through clouds can change their chemical and physical properties and thus modify how aerosols affect cloud microphysics and, subsequently, precipitation and climate. Current knowledge about aerosol processing by clouds is rather limited to chemical reactions within water droplets in warm low-altitude clouds. However, in cold high-altitude cirrus clouds and anvils of high convective clouds in the tropics and midlatitudes, humidified aerosols freeze to form ice, which upon exposure to subsaturation conditions with respect to ice can sublimate, leaving behind residual modified aerosols. This freeze-drying process can occur in various types of clouds. Here we simulate an atmospheric freeze-drying cycle of aerosols in laboratory experiments using proxies for atmospheric aerosols. We find that aerosols that contain organic material that undergo such a process can form highly porous aerosol particles with a larger diameter and a lower density than the initial homogeneous aerosol. We attribute this morphology change to phase separation upon freezing followed by a glass transition of the organic material that can preserve a porous structure after ice sublimation. A porous structure may explain the previously observed enhancement in ice nucleation efficiency of glassy organic particles. We find that highly porous aerosol particles scatter solar light less efficiently than nonporous aerosol particles. Using a combination of satellite and radiosonde data, we show that highly porous aerosol formation can readily occur in highly convective clouds, which are widespread in the tropics and midlatitudes. These observations may have implications for subsequent cloud formation cycles and aerosol albedo near cloud edges.

  14. Novel Real-Time Diagnosis of the Freezing Process Using an Ultrasonic Transducer

    Directory of Open Access Journals (Sweden)

    Yen-Hsiang Tseng

    2015-05-01

    Full Text Available The freezing stage governs several critical parameters of the freeze drying process and the quality of the resulting lyophilized products. This paper presents an integrated ultrasonic transducer (UT in a stainless steel bottle and its application to real-time diagnostics of the water freezing process. The sensor was directly deposited onto the stainless steel bottle using a sol-gel spray technique. It could operate at temperature range from −100 to 400 °C and uses an ultrasonic pulse-echo technique. The progression of the freezing process, including water-in, freezing point and final phase change of water, were all clearly observed using ultrasound. The ultrasonic signals could indicate the three stages of the freezing process and evaluate the cooling and freezing periods under various processing conditions. The temperature was also adopted for evaluating the cooling and freezing periods. These periods increased with water volume and decreased with shelf temperature (i.e., speed of freezing. This study demonstrates the effectiveness of the ultrasonic sensor and technology for diagnosing and optimizing the process of water freezing to save energy.

  15. Viability of Two Freeze-dried Strains of Bifidobacterium Preparations at Various Temperatures during Prolonged Storage

    Institute of Scientific and Technical Information of China (English)

    DU Peng; DU Li-hui; HUO Gui-cheng

    2005-01-01

    Viability of bifidobacteria in freeze-dried probiotic products at various temperatures during prolonged storage was assessed. Bifidobacterium longum and Bifidobacterium infantis were freeze-dried. The freeze-dried preparations were stored at -18,4, and 20℃. Cell counts were enumerated using BS agar at 37℃ for 48 h under anaerobic conditions at 0, 45 and 120 days. Storage at 20℃ showed the greatest decline in the viability of bifidobacteria, whereas that at -18℃ showed the least decrease.

  16. Mechanisms of deterioration of nutrients. [freeze drying methods for space flight food

    Science.gov (United States)

    Karel, M.; Flink, J. M.

    1974-01-01

    Methods are reported by which freeze dried foods of improved quality will be produced. The applicability of theories of flavor retention has been demonstrated for a number of food polymers, both proteins and polysacchardies. Studies on the formation of structures during freeze drying have been continued for emulsified systems. Deterioration of organoleptic quality of freeze dried foods due to high temperature heating has been evaluated and improved procedures developed. The influence of water activity and high temperature on retention of model flavor materials and browning deterioration has been evaluated for model systems and food materials.

  17. Antioxidant, antiproliferative and antimicrobial activity of freeze-dried raspberry

    Directory of Open Access Journals (Sweden)

    Vulić Jelena J.

    2014-01-01

    Full Text Available The main chemical composition, i.e. the total content of bioactive compounds (phenolics 2209.86 ± 70.32 mg GAE/100g FDR, flavonoids 831.87 ± 12.61 mg R/100g FDR and anthocyanins 144.55 ± 0.39 mg CGE/100g FDR, in freeze-dried raspberry (FDR was evaluated spectrophotometrically. Vitamin C content was determined by HPLC analysis (88.81 ± 4.38 mg vit C/100g FDR. Antioxidant activities of FDR extract were evaluated spectrophotometrically on stable 2,2-diphenyl-1-picrylhydrazyl (DPPH free radicals and by electron spin resonance spectroscopy (ESR method on hydroxyl radicals (•OH. EC50 values were evaluated. EC50 DPPH• was 0.127 ± 0.013 mg/ml, while EC50 •OH was 1.366 ± 0.026 mg/ml. Antiproliferative activity of the FDR extract was evaluated in vitro in three human cell lines by colorimetric sulphorhodamine B (SRB assay. The most pronounced effects were obtained in the breast adenocarcinoma cell line (MCF7. EC50 value was 395.07 ± 96.38 μg/ml. Antimicrobial activity was determined by disk diffusion method. The FDR extract produced a clear inhibition zone (without visible colonies only toward Staphylococcus aureus. The minimal inhibitory (MIC and minimal bactericidal (MBC concentrations of FDR extract were evaluated. The values MIC were in the range of 4.7 - 100 mg/ml, and of MBC in the range of 6.3 - > 100 mg/ml.[ Projekat Ministarstva nauke Republike Srbije, br. TR 31044

  18. Analysis and Application of the Amorphous Properties in Freeze-Dried Foods

    Science.gov (United States)

    Kawai, Kiyoshi

    The dynamic properties of amorphous materials drastically change by the phase transition between glassy state and rubber state. Furthermore, the dynamic properties of amorphous materials in glassy state are affected by the thermal history such as processing and/or storage conditions. In this paper, effect of the glass transition of freeze-dried food systems on the storage stability was summarized. Moreover, analytical approaches of the amorphous properties for glassy products with enthalpy relaxation measurements by using differential scanning calorimetry were presented and its application to food industry was proposed.

  19. Evaluation of Freeze-Dried Kefir Coculture as Starter in Feta-Type Cheese Production

    OpenAIRE

    Kourkoutas, Y.; Kandylis, P.; Panas, P.; Dooley, J. S. G.; P. Nigam; Koutinas, A. A.

    2006-01-01

    The use of freeze-dried kefir coculture as a starter in the production of feta-type cheese was investigated. Maturation of the produced cheese at 4°C was monitored for up to 70 days, and the effects of the starter culture, the salting method, and the ripening process on quality characteristics were studied. The use of kefir coculture as a starter led to increased lactic acid concentrations and decreased pH values in the final product associated with significantly higher conversion rates compa...

  20. Effects of stepwise dry/wet-aging and freezing on meat quality of beef loins.

    Science.gov (United States)

    Kim, Yuan H Brad; Meyers, Brandon; Kim, Hyun-Wook; Liceaga, Andrea M; Lemenager, Ronald P

    2017-01-01

    The objective of this study was to evaluate the effects of stepwise dry/wet-aging and freezing method on quality attributes of beef loins. Paired loins (M. Longissimus lumborum) from eight carcasses were assigned to either stepwise dry/wet-aging (carcass dry-aging for 10days then further wet-aging for 7days in vacuum bags) or carcass dry-aging only for 17days. Then, each loin was divided into three sections for freezing (never-frozen, blast or cryogenic freezing). Stepwise dry/wet-aged loin had lower purge/drip loss and shear force than conventionally dry-aged loin (P0.05). The cryogenic freezing resulted in a significant decrease in shear force values and a significant improvement in water-holding capacity (WHC). These findings indicate that the stepwise dry/wet-aging coupled with cryogenic freezing could provide beneficial impacts to the local meat industry by providing equivalent quality attributes as conventional dry-aging and improving WHC of frozen/thawed meat, while reducing the time needed for dry-aging.

  1. New particle dependant parameterizations of heterogeneous freezing processes.

    Science.gov (United States)

    Diehl, Karoline; Mitra, Subir K.

    2014-05-01

    For detailed investigations of cloud microphysical processes an adiabatic air parcel model with entrainment is used. It represents a spectral bin model which explicitly solves the microphysical equations. The initiation of the ice phase is parameterized and describes the effects of different types of ice nuclei (mineral dust, soot, biological particles) in immersion, contact, and deposition modes. As part of the research group INUIT (Ice Nuclei research UnIT), existing parameterizations have been modified for the present studies and new parameterizations have been developed mainly on the basis of the outcome of INUIT experiments. Deposition freezing in the model is dependant on the presence of dry particles and on ice supersaturation. The description of contact freezing combines the collision kernel of dry particles with the fraction of frozen drops as function of temperature and particle size. A new parameterization of immersion freezing has been coupled to the mass of insoluble particles contained in the drops using measured numbers of ice active sites per unit mass. Sensitivity studies have been performed with a convective temperature and dew point profile and with two dry aerosol particle number size distributions. Single and coupled freezing processes are studied with different types of ice nuclei (e.g., bacteria, illite, kaolinite, feldspar). The strength of convection is varied so that the simulated cloud reaches different levels of temperature. As a parameter to evaluate the results the ice water fraction is selected which is defined as the relation of the ice water content to the total water content. Ice water fractions between 0.1 and 0.9 represent mixed-phase clouds, larger than 0.9 ice clouds. The results indicate the sensitive parameters for the formation of mixed-phase and ice clouds are: 1. broad particle number size distribution with high number of small particles, 2. temperatures below -25°C, 3. specific mineral dust particles as ice nuclei such

  2. Sperm preservation by freeze-drying for the conservation of wild animals.

    Directory of Open Access Journals (Sweden)

    Takehito Kaneko

    Full Text Available Sperm preservation is a useful technique for the maintenance of biological resources in experimental and domestic animals, and in wild animals. A new preservation method has been developed that enables sperm to be stored for a long time in a refrigerator at 4 °C. Sperm are freeze-dried in a solution containing 10 mM Tris and 1 mM EDTA. Using this method, liquid nitrogen is not required for the storage and transportation of sperm. We demonstrate that chimpanzee, giraffe, jaguar, weasel and the long-haired rat sperm remain viable after freeze-drying. In all species, pronuclei were formed after the injection of freeze-dried sperm into the mouse oocytes. Although preliminary, these results may be useful for the future establishment of "freeze-drying zoo" to conserve wild animals.

  3. Effect of freeze-drying on the antioxidant compounds and antioxidant activity of selected tropical fruits.

    Science.gov (United States)

    Shofian, Norshahida Mohamad; Hamid, Azizah Abdul; Osman, Azizah; Saari, Nazamid; Anwar, Farooq; Dek, Mohd Sabri Pak; Hairuddin, Muhammad Redzuan

    2011-01-01

    The effects of freeze-drying on antioxidant compounds and antioxidant activity of five tropical fruits, namely starfruit (Averrhoa carambola L.), mango (Mangifera indica L.), papaya (Carica papaya L.), muskmelon (Cucumis melo L.), and watermelon Citruluss lanatus (Thunb.) were investigated. Significant (p 0.05) change, however, observed in the ascorbic acid content of the fresh and freeze-dried fruits. Similarly, freeze-drying did not exert any considerable effect on β-carotene concentration of fruits, except for mango and watermelon, where significantly (p inhibition measurement, a significant (p < 0.05) but random variation was recorded between the fresh and freeze-dried fruits. Overall, in comparison to β-carotene and ascorbic acid, a good correlation was established between the result of TPC and antioxidant assays, indicating that phenolics might have been the dominant compounds contributing towards the antioxidant activity of the fruits tested.

  4. Experimental Research on Drying Technology based on Vacuum Freezing Dryer%黄瓜片真空冷冻干燥试验

    Institute of Scientific and Technical Information of China (English)

    王慧贤

    2012-01-01

    Vacuum freeze-drying technology is a new kind of food processing method which integrates with vacuum technotogy, freezing ano drying technology. The principle of vacuum freeze-drying technology, drying technology and freeze-drying equipment were briefly introduced. Cucumber drying experiment by applying vacuum freezing dryer was mainly introduced, and the cucumber vacuum freeze-drying curve was plotted, and the changes of cucumber color, shape, and weight were contrasted before and after drying, which were analyzed by the software MATLAB and electronic balance, and then the average moisture content, drying rate and surface area shrinkage rate..%为优化黄瓜真空冷冻干燥工艺,以黄瓜片为试材,采用MATLAB软件分析黄瓜片真空冷冻干燥前后的质量、色泽、形状变化。试验结果表明:黄瓜的平均含水率为96.3%;干燥后的表面收缩率为0.332471;干燥前的r、g、b色度坐标值为0.3562、0.3595、0.2842,干燥后分别为0.2835、0.4295、0.2871。

  5. Freeze-drying process optimization and characteristics of PEG modified artemisinin-loaded nanostructured lipid carriers%聚乙二醇修饰青蒿素脂质纳米粒冻干工艺优化及其表征

    Institute of Scientific and Technical Information of China (English)

    赵青; 王芳; 王锐利; 张丽锋; 张淑秋

    2015-01-01

    Objective To screen the optimal formula of cryoprotectants for PEG modified artemisinin-loaded nanostructured lipid carriers (PEG-ART-NLC) and to investigate its freeze-drying process and characteristics. Methods Different cryoprotectants were used to prepare PEG-ART-NLC freeze-drying powder. The cryoprotectants were optimized based on the appearance, redispersibility, redissolved appearance, particle size and Zeta potential of the PEG-ART-NLC freeze-drying powder. The quality changes of PEG-ART-NLC before and after freeze-drying were compared. Results The mixture of 4%mannitol and 4%sucrose showed good protective effect and redispersibility. The PEG-ART-NLC par-ticle size was increased by 14.0 nm, and the Zeta potential absolute value and encapsulation efficiency were decreased by 8.8 mV and 14.5%, respectively. The morphology of the PEG-ART-NLC freeze-drying powder was round or oval un-der electron microscope before and after freeze-drying, without significant differences. Conclusion A stable kind of PEG-ART-NLC freeze-drying powder can be prepared by the optimal cryoprotectants of 4%mannitol and 4%sucrose.%目的:筛选聚乙二醇(PEG)修饰青蒿素脂质纳米粒(PEG-ART-NLC)最优冻干保护剂处方,研究其冷冻干燥工艺及质量表征。方法制备含不同冻干保护剂的PEG-ART-NLC冻干粉,以外观、再分散性、复溶后外观、粒径、Zeta电位为指标,优化保护剂处方,并对比冻干前后脂质纳米粒质量变化。结果4%甘露醇和4%蔗糖具良好的保护作用和再分散性,冻干后纳米粒粒径增大14.0 nm,Zeta电位绝对值降低8.8 mV,包封率降低14.5%,电镜下冻干前后纳米粒形态均为圆形或椭圆形,无明显差异。结论4%甘露醇和4%蔗糖为最优保护剂处方,可用于制备稳定的PEG-ART-NLC冻干粉。

  6. Cell viability of microencapsulated Bifidobacterium animalis subsp. lactis under freeze-drying, storage and gastrointestinal tract simulation conditions.

    Science.gov (United States)

    Shamekhi, Fatemeh; Shuhaimi, Mustafa; Ariff, Arbakariya; Manap, Yazid A

    2013-03-01

    The purpose of this study was to improve the survival of Bifidobacterium animalis subsp. lactis 10140 during freeze-drying process by microencapsulation, using a special pediatric prebiotics mixture (galactooligosaccharides and fructooligosaccharides). Probiotic microorganisms were encapsulated with a coat combination of prebiotics-calcium-alginate prior to freeze-drying. Both encapsulated and free cells were then freeze-dried in their optimized combinations of skim milk and prebiotics. Response surface methodology (RSM) was used to produce a coating combination as well as drying medium with the highest cell viability during freeze-drying. The optimum encapsulation composition was found to be 2.1 % Na-alginate, 2.9 % prebiotic, and 21.7 % glycerol. Maximum survival predicted by the model was 81.2 %. No significant (p > 0.05) difference between the predicted and experimental values verified the adequacy of final reduced models. The protection ability of encapsulation was then examined over 120 days of storage at 4 and 25 °C and exposure to a sequential model of infantile GIT conditions including both gastric conditions (pH 3.0 and 4.0, 90 min, 37 °C) and intestinal conditions (pH 7.5, 5 h, 37 °C). Significantly improved cell viability showed that microencapsulation of B. lactis 10140 with the prebiotics was successful in producing a stable symbiotic powdery nutraceutical.

  7. Effects of Food Additives on Drying Rate, Rehydration Ratio and Sense Value of Freeze-dried Dumplings

    Directory of Open Access Journals (Sweden)

    Xingli Jiao

    2015-07-01

    Full Text Available Dumpling has always been a traditional and delicious food in China. Nevertheless, the rehydration effects, especially the nip of dumplings, are far from people’s satisfaction. To solve this problem, in this study, aimed at the improving the rehydration properties of freeze-dried dumplings, three kinds of food additives, including compound phosphate, soybean lecithin and guar gum, were added into dumplings wrappers. Results showed that, the drying rate, rehydration ratio and sense value were the highest with respective addition of 0.1% compound phosphate, 0.6% soybean lecithin and 0.35% guar gum. The interactions between freeze-dried dumplings and food additives were discussed, which provided the theory foundation for preparation of freeze-dried food.

  8. Design of self-dispersible dry nanosuspension through wet milling and spray freeze-drying for poorly water-soluble drugs.

    Science.gov (United States)

    Niwa, Toshiyuki; Danjo, Kazumi

    2013-11-20

    The purpose of the present research is to establish a novel nanosizing technique starting from wet nano-milling, named "dry nanosuspension" technique for poorly water-soluble drugs. The spray freeze-drying (SFD) method was applied instead of the spray-drying one previously developed. Drug particles were milled in the aqueous solution of dispersing agents using an oscillating beads-milling apparatus. The milled nanosuspension was sprayed to the surface of liquid nitrogen, and the resultant iced droplets were freeze-dried to obtain the powdery product. The loading ratio of a dispersing agent was investigated to enhance its redispersing property. Dry nanosuspension, which could be spontaneously dispersed into original nanosuspension in water, was obtained by SFD process. It was assumed that self dispersion property would be attributed to its structure with porous network, in which the primary milled drug crystals were embedded. Such unique structure contributed greatly to immediate release behaviors of the drug in gastrointestinal buffered media. These pharmaceutical properties were enhanced by increasing the ratio of the dispersing agent to the drug and the solid content in suspension to be sprayed. The present technique via wet milling and spray freeze-drying processes would be a novel dissolution-enhanced technology for poorly water-soluble drugs.

  9. Spray freeze drying as an alternative technique for lyophilization of polymeric and lipid-based nanoparticles.

    Science.gov (United States)

    Ali, Mohamed Ehab; Lamprecht, Alf

    2017-01-10

    The use of nanoparticles for drug delivery is still restricted by their limited stability when stored in an aqueous medium. Freeze drying is the standard method for long-term storage of colloidal nanoparticles; however the method needs to be elaborated for each formulation. Spray freeze drying (SFD) is proposed here as a promising alternative for lyophilizing colloidal nanoparticles. Different types of polymeric and lipid nanoparticles were prepared and characterized. Afterwards, samples were spray freeze dried by spraying into a column of cold air with a constant concentration of different cryoprotectants, and the frozen spherules were collected for further freeze drying. Similar samples were prepared using the commonly used technique, freeze drying, as controls. Using SFD, fast-dissolving, spherical and porous nanocomposite microparticles with remarkably high flowability (CI≤10) were produced. On the contrary to similar samples prepared using the freeze drying technique, the investigated polymeric and lipid nanoparticles were completely reconstituted (Sf/Si ratio nanoparticles. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Production of grape juice powder obtained by freeze-drying after concentration by reverse osmosis

    Directory of Open Access Journals (Sweden)

    Poliana Deyse Gurak

    2013-12-01

    Full Text Available This study aimed to evaluate the freeze-drying process for obtaining grape juice powder by reverse osmosis using 50% grape juice pre-concentrated (28.5 °Brix and 50% hydrocolloids (37.5% maltodextrin and 12.5% arabic gum. The morphology of the glassy food showed the absence of crystalline structure, which was the amorphous wall that protected the contents of the powder. The samples were stored in clear and dark containers at room temperature, evaluated for their physical (X-ray diffraction for 65 days and chemical (polyphenol content stability for 120 days. During the storage time in plastic vessels, samples remained physically stable (amorphous and the phenolic concentration was constant, indicating the potentiality of this technique to obtain a stable product with a high concentration of phenolic compounds. Therefore, the freeze-drying process promoted the encapsulation of concentrated grape juice increasing its stability and shelf life, as well as proving to be an applicable process to food industry

  11. Freeze-Drying Technology and Strategies for Biological Products%生物制品冷冻干燥技术与策略

    Institute of Scientific and Technical Information of China (English)

    朱明文

    2012-01-01

    基于对现代冻干技术进展研究和多年生物制品实际冻干经验,探讨了影响冻干的重要因素、环节以及技术和对策。冷冻干燥技术研发和工业化是复杂的系统工程,仅靠传统方法已难于有效控制,应建立以科学为基础,通过质量设计、风险评估和过程控制,优化和控制冻干过程,获取优良冻干产品,提高生产效率,降低成本。通过冻干应用技术研究,为生物制品冻干研发和生产以及产品的质量控制提供参考。%Based on research on development of modern freeze drying technology and the experience in actual freezing and drying of biological products for years,this paper discusses important factors affecting freeze-dried effect,technologies and strategies.Freeze drying technology development and industrialization is a complex system engineering,traditional methods alone are difficult to effectively control.A kind of scientific basis should be established,the freeze drying process is optimized and controlled by quality design,risk assessment and process quality control to get excellent freeze dried product,improve freeze-dehydration production time,reduce costs.Through the research on application of the freeze drying technology,it provides the reference for freeze-dried biologicals development,production and product quality control.

  12. Computer-Aided Framework for the Design of Freeze-Drying Cycles: Optimization of the Operating Conditions of the Primary Drying Stage

    Directory of Open Access Journals (Sweden)

    Davide Fissore

    2015-05-01

    Full Text Available This paper deals with the freeze-drying process and, in particular, with the optimization of the operating conditions of the primary drying stage. When designing a freeze-drying cycle, process control aims at obtaining the values of the operating conditions (temperature of the heating fluid and pressure in the drying chamber resulting in a product temperature lower than the limit value of the product, and in the shortest drying time. This is particularly challenging, mainly due to the intrinsic nonlinearity of the system. In this framework, deep process knowledge is required for deriving a suitable process dynamic model that can be used to calculate the design space for the primary drying stage. The design space can then be used to properly design (and optimize the process, preserving product quality. The case of a product whose dried layer resistance, one of the key model parameters, is affected by the operating conditions is addressed in this paper, and a simple and effective method to calculate the design space in this case is presented and discussed.

  13. Impact of Microscale and Pilot-Scale Freeze-Drying on Protein Secondary Structures: Sucrose Formulations of Lysozyme and Catalase.

    Science.gov (United States)

    Peters, Björn-Hendrik; Leskinen, Jari T T; Molnár, Ferdinand; Ketolainen, Jarkko

    2015-11-01

    Microscale (MS) freeze-drying offers rapid process cycles for early-stage formulation development. The effects of the MS approach on the secondary structures of two model proteins, lysozyme and catalase, were compared with pilot-scale (PS) vial freeze-drying. The secondary structures were assessed by attenuated total reflection Fourier transformed infrared spectroscopy. Formulations were made with increasing sucrose-protein ratios. Freeze-drying protocols involved regular cooling without thermal treatment and annealing with MS and PS equipment, and cooling rate variations with the MS. Principal component analysis of smoothed second-derivative amide I spectra revealed sucrose-protein ratio-dependent shifts toward α-helical structures. Transferability of sucrose-protein formulations from MS to PS vial freeze-drying was evidenced at regular cooling rates. Local differences in protein secondary structures between the bottom and top of sucrose-catalase samples could be detected at the sucrose-catalase ratios of 1 and 2, this being related to the initial filling height and ice crystal morphology. Annealing revealed temperature, protein, formulation, and sample location-dependent effects influencing surface morphology at the top, or causing protein secondary structure perturbation at the bottom. With the MS approach, protein secondary structure differences at different cooling rates could be detected for sucrose-lysozyme samples at the sucrose-lysozyme ratio of 1.

  14. Microbial analysis and survey test of gamma-irradiated freeze-dried fruits for patient's food

    Science.gov (United States)

    Park, Jae-Nam; Sung, Nak-Yun; Byun, Eui-Hong; Byun, Eui-Baek; Song, Beom-Seok; Kim, Jae-Hun; Lee, Kyung-A.; Son, Eun-Joo; Lyu, Eun-Soon

    2015-06-01

    This study examined the microbiological and organoleptic qualities of gamma-irradiated freeze-dried apples, pears, strawberries, pineapples, and grapes, and evaluated the organoleptic acceptability of the sterilized freeze-dried fruits for hospitalized patients. The freeze-dried fruits were gamma-irradiated at 0, 1, 2, 3, 4, 5, 10, 12, and 15 kGy, and their quality was evaluated. Microorganisms were not detected in apples after 1 kGy, in strawberries and pears after 4 kGy, in pineapples after 5 kGy, and in grapes after 12 kGy of gamma irradiation. The overall acceptance score, of the irradiated freeze-dried fruits on a 7-point scale at the sterilization doses was 5.5, 4.2, 4.0, 4.1, and 5.1 points for apples, strawberries, pears, pineapples, and grapes, respectively. The sensory survey of the hospitalized cancer patients (N=102) resulted in scores of 3.8, 3.7, 3.9, 3.9, and 3.7 on a 5-point scale for the gamma-irradiated freeze-dried apples, strawberries, pears, pineapples, and grapes, respectively. The results suggest that freeze-dried fruits can be sterilized with a dose of 5 kGy, except for grapes, which require a dose of 12 kGy, and that the organoleptic quality of the fruits is acceptable to immuno-compromised patients. However, to clarify the microbiological quality and safety of freeze-dried fruits should be verified by plating for both aerobic and anaerobic microorganisms.

  15. Effect of freeze-drying and self-ignition process on the microstructural and electrochemical properties of Li{sub 4}Ti{sub 5}O{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Jamin, Claire [GREEnMat/LCIS, Department of Chemistry, B6a, University of Liège, Sart-Tilman, 4000 Liège (Belgium); Traina, Karl [GREEnMat/LCIS, Department of Chemistry, B6a, University of Liège, Sart-Tilman, 4000 Liège (Belgium); APTIS, Department of Physics, B5a, University of Liège, Sart-Tilman, 4000 Liège (Belgium); Eskenazi, David [Chemical Engineering Laboratory, Department of Applied Chemistry, B6a, University of Liège, Sart-Tilman, 4000 Liège (Belgium); Krins, Natacha; Cloots, Rudi; Vertruyen, Bénédicte [GREEnMat/LCIS, Department of Chemistry, B6a, University of Liège, Sart-Tilman, 4000 Liège (Belgium); Boschini, Frédéric, E-mail: frederic.boschini@ulg.ac.be [GREEnMat/LCIS, Department of Chemistry, B6a, University of Liège, Sart-Tilman, 4000 Liège (Belgium); APTIS, Department of Physics, B5a, University of Liège, Sart-Tilman, 4000 Liège (Belgium)

    2013-11-15

    Graphical abstract: - Highlights: • Li{sub 4}Ti{sub 5}O{sub 12} is prepared by a method involving self-ignition of a freeze-dried gel. • Addition of NH{sub 4}NO{sub 3} modifies the self-ignition propagation mode. • Well-crystallized Li{sub 4}Ti{sub 5}O{sub 12} phase is obtained after only 2 h at 800 °C. • Li{sub 4}Ti{sub 5}O{sub 12} powder has 161 mAh g{sup −1} capacity and good retention at C/4 rate. - Abstract: Crystalline Li{sub 4}Ti{sub 5}O{sub 12} is synthesized by a method involving the freeze-drying and self-ignition of a gel prepared from titanium isopropoxide, lithium nitrate and hydroxypropylmethylcellulose (HPMC). This synthesis route yields crystalline Li{sub 4}Ti{sub 5}O{sub 12} particles after calcination at 800 °C for 2 h. In an alternative route, addition of ammonium nitrate shifts the self-ignition mode from wave-like propagation to simultaneous. Powders with different microstructures are thereby obtained. Electrochemical characterization shows that the best results for Li{sup +} intercalation/desintercalation are obtained for the powder prepared without ammonium nitrate addition. These results highlight the necessity for a control of the self-ignition mode to obtain adequate properties.

  16. Optimization of the bioactive compounds content in raspberry during freeze-drying using response surface method

    Directory of Open Access Journals (Sweden)

    Tumbas-Šaponjac Vesna T.

    2015-01-01

    Full Text Available The production of high-quality freeze-dried raspberry was studied by response surface method. Two independent variables, temperature (X1 and time (X2 were determined as the most important factors affecting the final product quality estimated by the responses: total phenol (Y1, total anthocyanin (Y2, vitamin C (Y3 and total bioactive compounds (Y4 content. A two-factor central composite design was used for freeze-drying experiments. The second order polynomial models obtained were found to be significant (p<0.05 for all responses. The statistical analysis of experimental data indicated that only quadratic time variable (X22 had significant (p<0.05 effect on all responses. The optimal conditions for all responses combined were found to be: -31 ºC and 35 h. The experimental values of all responses obtained under optimal conditions were in good agreement with predicted values which enables the use of the proposed mathematical models for optimization of investigated process. [Projekat Ministarstav nauke Republike Srbije, br. TR31044

  17. Preparation of freeze-dried coffee tablets%冻干咖啡片的研制

    Institute of Scientific and Technical Information of China (English)

    陈三宝

    2012-01-01

    The freeze-dried coffee tablets were prepared by hot water extraction and freeze drying with coffee extract as the raw material.The optimal process was that the temperature of the extract of coffee was 90℃,extract time 12 min,the ratio of coffee to water%以咖啡粉为原料,采用热水提取、冷冻干燥的方法,制备了冻干咖啡片。通过实验确定最佳制片方案为:咖啡粉浸提温度90℃,浸提时间12min,料液比为1:15,提取液浓缩至65%浓度,于共熔点温度-36℃以下冷冻干燥。按优选工艺制得的冻干咖啡片硬度适当,片型完整,溶解迅速,具有较速溶咖啡更好的风味、复水性和感官品质。

  18. Tert-butyl alcohol used to fabricate nano-cellulose aerogels via freeze-drying technology

    Science.gov (United States)

    Wang, Xiaoyu; Zhang, Yang; Jiang, Hua; Song, Yuxuan; Zhou, Zhaobing; Zhao, Hua

    2017-06-01

    Aerogel, a highly porous material, is attracting increasing attention owing to low thermal conductivity and high specific surface area. Freeze-drying technology has been employed to produce nano-cellulose aerogels; however, the resultant product has low specific surface areas. Here, a modified approach to prepare nano-cellulose aerogels was reported, which involves tert-butyl alcohol as a solvent. Nano-cellulose aerogels were prepared via a spontaneous gelation fashion using calcium chloride solution, followed by tert-butyl alcohol solvent displacement and freeze drying. Addition of calcium chloride (0.25%) accelerated the physical gelation process. The application of tert-butyl alcohol as a solvent contributed to preservation of gel network. The obtained spherical nano-cellulose aerogels had a shrinkage rate of 5.89%. The specific surface area and average pore size was 164. 9666 m2 g-1 and 10.01 nm, respectively. Additionally, nano-cellulose aerogels had a comparable thermal degradation property when compared to microcrystalline cellulose. These biophysical properties make nano-cellulose aerogels as a promising absorption material.

  19. Demineralized Freeze-Dried Bovine Cortical Bone: Its Potential for Guided Bone Regeneration Membrane

    Directory of Open Access Journals (Sweden)

    David B. Kamadjaja

    2017-01-01

    Full Text Available Background. Bovine pericardium collagen membrane (BPCM had been widely used in guided bone regeneration (GBR whose manufacturing process usually required chemical cross-linking to prolong its biodegradation. However, cross-linking of collagen fibrils was associated with poorer tissue integration and delayed vascular invasion. Objective. This study evaluated the potential of bovine cortical bone collagen membrane for GBR by evaluating its antigenicity potential, cytotoxicity, immune and tissue response, and biodegradation behaviors. Material and Methods. Antigenicity potential of demineralized freeze-dried bovine cortical bone membrane (DFDBCBM was done with histology-based anticellularity evaluation, while cytotoxicity was analyzed using MTT Assay. Evaluation of immune response, tissue response, and biodegradation was done by randomly implanting DFDBCBM and BPCM in rat’s subcutaneous dorsum. Samples were collected at 2, 5, and 7 days and 7, 14, 21, and 28 days for biocompatibility and tissue response-biodegradation study, respectively. Result. DFDBCBM, histologically, showed no retained cells; however, it showed some level of in vitro cytotoxicity. In vivo study exhibited increased immune response to DFDBCBM in early healing phase; however, normal tissue response and degradation rate were observed up to 4 weeks after DFDBCBM implantation. Conclusion. Demineralized freeze-dried bovine cortical bone membrane showed potential for clinical application; however, it needs to be optimized in its biocompatibility to fulfill all requirements for GBR membrane.

  20. Constant size, variable density aerosol particles by ultrasonic spray freeze drying.

    Science.gov (United States)

    D'Addio, Suzanne M; Chan, John Gar Yan; Kwok, Philip Chi Lip; Prud'homme, Robert K; Chan, Hak-Kim

    2012-05-10

    This work provides a new understanding of critical process parameters involved in the production of inhalation aerosol particles by ultrasonic spray freeze drying to enable precise control over particle size and aerodynamic properties. A series of highly porous mannitol, lysozyme, and bovine serum albumin (BSA) particles were produced, varying only the solute concentration in the liquid feed, c(s), from 1 to 5 wt%. The particle sizes of mannitol, BSA, and lysozyme powders were independent of solute concentration, and depend only on the drop size produced by atomization. Both mannitol and lysozyme formulations showed a linear relationship between the computed Fine Particle Fraction (FPF) and the square root of c(s), which is proportional to the particle density, ρ, given a constant particle size d(g). The FPF decreased with increasing c(s) from 57.0% to 16.6% for mannitol and 44.5% to 17.2% for lysozyme. Due to cohesion, the BSA powder FPF measured by cascade impaction was less than 10% and independent of c(s). Ultrasonic spray freeze drying enables separate control over particle size, d(g), and aerodynamic size, d(a) which has allowed us to make the first experimental demonstration of the widely accepted rule d(a)=d(g)(ρ/ρ(o))(1/2) with particles of constant d(g), but variable density, ρ (ρ(o) is unit density).

  1. Effect of drying, freezing and storage of dried and frozen onion (Allium cepa L.) on its pungency

    OpenAIRE

    Marcin Horbowicz; Józef Bąkowski

    2013-01-01

    The paper contains results of studies of drying and freezing effects, as well as storage of dried and frozen onion on its pungency. The effect of onion bulbs preparation on pungency was estimated as well. The pungency measurements were based on determination of pyruvate produced enzymatically by alliinase. Storage at 20°C of skinned onion decreases sligthly pungency, however three weeks storage at 0-2°C did not change it. Other results indicate that freezing at -25°C, and followed thawing led...

  2. 真空冷冻干燥与喷雾干燥长双歧杆菌的工艺比较研究%Comparison of Vacuum Freeze-Drying and Spray-Drying Processes for Active Bifidobacterium longum Powder Production

    Institute of Scientific and Technical Information of China (English)

    付博; 马齐; 王卫卫; 炯力

    2012-01-01

    为有效延长双歧杆菌的保存期和耐受性,利用真空冷冻干燥及喷雾干燥法制备活性菌粉。研究两种干燥方法的工艺参数,并对干燥得到的活性菌粉性能进行比较。真空冷冻干燥法制备的长双歧杆菌活性菌粉的活菌数为7.98×10^9CFU/g、存活率90.9%、含水量3.8%,4℃保藏90d后活菌数为2.5×10^8CFU/g,菌粉的水溶性好;喷雾干燥法制备的活性菌粉的活菌数为4.4×10^9CFU/g、存活率82.2%、包埋率71.9%、含水量5.6%,4~C保藏90d后活菌数为4×10^8CFU/g,菌粉在水中的溶解时间较长。真空冷冻干燥成本较高、操作时间长、菌粉的保藏期较短;而喷雾干燥工艺简单、生产成本低、工作效率高,包埋的菌粉保藏期较长。%For long term storage and to improve its stress resistance, Bifidobacterium longum was made into active bacteria powder by vacuum freeze-drying or spray-drying. In this study, we first optimized the technological conditions for active Bifidobacterium longum powder production and then compared these two processes in term of bacterial survival rate, cost, and ease of operation. The viable count, survival rate, moisture and viable count after storage for 90 days at 4 ℃ of vacuum freezedried active Bifidobacterium longum powder were 7.98 × 10^9 CFU/g, 90.9%, 3.8%, and 2.5 ×10^8 CFU/g, respectively. The powder dissolved easily in water: In contrast, the viable count, survival rate, encapsulation efficiency, moisture and viable count after storage for 90 days at 4 ℃ of spray-dried Bifutobacterium longum powder were 4.4× 10^9 CFU/g, 82.2%, 71.9%, 5.6% and 4× 10^8 CFU/g, respectively. It took longer time to dissolve in water when compared to vacuum-freeze dried powder. Vacuum freeze-drying was more complicated to operate, time-consuming and expensive than spray-drying. In conclusion, these two processes have both their advantages and disadvantages, which make

  3. The impact of freeze-drying infant fecal samples on measures of their bacterial community profiles and milk-derived oligosaccharide content

    Directory of Open Access Journals (Sweden)

    Zachery T. Lewis

    2016-01-01

    Full Text Available Infant fecal samples are commonly studied to investigate the impacts of breastfeeding on the development of the microbiota and subsequent health effects. Comparisons of infants living in different geographic regions and environmental contexts are needed to aid our understanding of evolutionarily-selected milk adaptations. However, the preservation of fecal samples from individuals in remote locales until they can be processed can be a challenge. Freeze-drying (lyophilization offers a cost-effective way to preserve some biological samples for transport and analysis at a later date. Currently, it is unknown what, if any, biases are introduced into various analyses by the freeze-drying process. Here, we investigated how freeze-drying affected analysis of two relevant and intertwined aspects of infant fecal samples, marker gene amplicon sequencing of the bacterial community and the fecal oligosaccharide profile (undigested human milk oligosaccharides. No differences were discovered between the fecal oligosaccharide profiles of wet and freeze-dried samples. The marker gene sequencing data showed an increase in proportional representation of Bacteriodes and a decrease in detection of bifidobacteria and members of class Bacilli after freeze-drying. This sample treatment bias may possibly be related to the cell morphology of these different taxa (Gram status. However, these effects did not overwhelm the natural variation among individuals, as the community data still strongly grouped by subject and not by freeze-drying status. We also found that compensating for sample concentration during freeze-drying, while not necessary, was also not detrimental. Freeze-drying may therefore be an acceptable method of sample preservation and mass reduction for some studies of microbial ecology and milk glycan analysis.

  4. Stability study perspective of the effect of freeze-drying using cryoprotectants on the structure of insulin loaded into PLGA nanoparticles.

    Science.gov (United States)

    Fonte, Pedro; Soares, Sandra; Sousa, Flávia; Costa, Ana; Seabra, Vítor; Reis, Salette; Sarmento, Bruno

    2014-10-13

    This work aimed to evaluate the influence of a freeze-drying process using different cryoprotectants on the structure of insulin loaded into poly(lactic-co-glycolic acid) (PLGA) nanoparticles and to assess the stability of these nanoparticles upon 6 months of storage following ICH guidelines. Insulin-loaded PLGA nanoparticles with a size around 450 nm were dehydrated using a standard freeze-drying cycle, using trehalose, glucose, sucrose, fructose, and sorbitol at 10% (w/v) as cryoprotectants. All formulations, except those nonadded of cryoprotectant and added with trehalose, collapsed after freeze-drying. The addition of cryoprotectants increased the nanoparticles stability upon storage. FTIR results showed that insulin maintained its structure after encapsulation in about 88%, decreasing to 71% after freeze-drying. The addition of cryoprotectants prior to freeze-drying increased insulin structural stability an average of up to 79%. Formulations collapsed after freeze-drying showed better protein stabilization upon storage, in special sorbitol added formulation, preserving 76, 80, and 78% of insulin structure at 4 °C, 25 °C/60% RH, and 40 °C/75% RH, respectively. Principal component analysis also showed that the sorbitol-added formulation showed the most similar insulin structural modifications among the tested storage conditions. These findings suggested that regarding nanoparticles stability, cryoprotectants are versatile to be used in a standard freeze-drying, however they present different performances on the stabilization of the loaded protein. Thus, on the freeze-drying of the nanoparticles field, this work gives rise to the importance of the process of optimization, searching for a balance between a good obtainable cake with an optimal structural stabilization of the loaded protein.

  5. Anti- and pro-oxidative effect of fresh and freeze-dried vegetables during storage of mayonnaise.

    Science.gov (United States)

    Raikos, Vassilios; Neacsu, Madalina; Morrice, Philip; Duthie, Garry

    2015-12-01

    Mayonnaise was supplemented with vegetables (5 % w/w) and the effect of storage time at 4 °C on the oxidative stability of the dispersed phase was investigated. Results indicated that mayonnaise is prone to lipid oxidation during storage under refrigerator conditions. The type of vegetable used for mayonnaise reformulation was critical in inhibiting oxidation and followed the order beetroot > carrot ≈ onion with respect to antioxidant capacity. Broccoli induced a pro-oxidant effect and the rate of oxidation by the end of the storage period was 42 times higher compared with the control. The addition of beetroot, either fresh or freeze-dried, improved the oxidative stability of mayonnaise significantly. The process of freeze-drying affected adversely the ability of vegetables to decrease oil oxidation of the emulsions. This may reflect loss of important natural antioxidants during the drying procedure.

  6. Development of Freeze-Dried Bacteriocin-Containing Preparations from Lactic Acid Bacteria to Inhibit Listeria monocytogenes and Staphylococcus aureus.

    Science.gov (United States)

    Dimitrieva-Moats, Galina Yu; Ünlü, Gülhan

    2012-03-01

    There has been a recent movement to produce and consume "minimally processed" and more "natural" foods through the use of fewer chemical preservatives. The shift to more "natural" foods has resulted in a great interest in the use of bacteriocins from lactic acid bacteria as natural biopreservatives. The objective of this comparative study was to identify bacteriocins that can be produced in low-cost or no-cost dairy-based media (DBM), concentrated using freeze-drying, and applied to Cheddar cheese samples to concurrently inhibit Listeria monocytogenes and Staphylococcus aureus. Select bacteriocin producers were grown in DBM, their cell-free supernatants (CFS) were frozen, and the frozen CFS samples were freeze-dried to produce bacteriocin-containing powders. Cheddar cheese samples were challenged with L. monocytogenes or Staph. aureus cells. The challenged samples were exposed to buffered solutions of freeze-dried powders containing bacteriocins, incubated at 4 °C for 24-72 h, and plated onto appropriate selective media. All freeze-dried bacteriocin-containing powders tested were active against L. monocytogenes and Staph. aureus. Our research findings indicated that low-cost or no-cost DBM could successfully be used for production of bacteriocin-containing preparations. In addition, freeze-drying was determined to be a feasible approach to prepare concentrated and stable bacteriocin-containing powders for prospective food applications. The prevention of even a very small percentage of foodborne illnesses via the use of bacteriocins as natural biopreservatives would help reduce the number of foodborne illness-related hospitalizations, deaths, and financial loss due to medical expenses, lost income/productivity, cost of litigation/penalties, and loss of trade.

  7. Preserving the supersaturation generation capability of amorphous drug-polysaccharide nanoparticle complex after freeze drying.

    Science.gov (United States)

    Kiew, Tie Yi; Cheow, Wean Sin; Hadinoto, Kunn

    2015-04-30

    While the supersaturation generation capability of amorphous nanopharmaceuticals (NPs) in their aqueous suspension form has been well established, their supersaturation generation is adversely affected after drying. Herein we investigated the effects of freeze drying on the supersaturation generation capability of a new class of amorphous NPs referred to as drug nanoplex prepared and stabilized by electrostatic complexation of drug molecules with polysaccharides (dextran sulfate). Using ciprofloxacin as the model drug, two types of freeze-drying adjuvants were investigated, i.e., (1) highly water-soluble excipient (trehalose, mannitol), whose role was to prevent irreversible NPs aggregations upon drying, and (2) crystallization inhibitor (hydroxypropylmethylcellulose (HPMC)), whose role was to suppress crystallization of the dissolved drug and the remaining solid phase. The results showed that dual-adjuvant formulations (i.e. trehalose-HPMC and mannitol-HPMC) were required to preserve the supersaturation generation capability of the drug nanoplex suspension after drying. Freeze drying with only one adjuvant type, or incorporating HPMC as physical mixtures with the freeze-dried nanoplex, were ineffective in preserving the supersaturation. The dual-adjuvant formulations produced prolonged supersaturation levels over 240min at ≈6-8× of the saturation solubility with comparable area under the curve (AUC) in the concentration versus time plot as that exhibited by the suspension form. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Effect of Freeze-Drying on the Antioxidant Compounds and Antioxidant Activity of Selected Tropical Fruits

    Directory of Open Access Journals (Sweden)

    Muhammad Redzuan Hairuddin

    2011-07-01

    Full Text Available The effects of freeze-drying on antioxidant compounds and antioxidant activity of five tropical fruits, namely starfruit (Averrhoa carambola L., mango (Mangifera indica L., papaya (Carica papaya L., muskmelon (Cucumis melo L., and watermelon Citruluss lanatus (Thunb. were investigated. Significant (p < 0.05 differences, for the amounts of total phenolic compounds (TPC, were found between the fresh and freeze-dried fruit samples, except muskmelon. There was no significant (p > 0.05 change, however, observed in the ascorbic acid content of the fresh and freeze-dried fruits. Similarly, freeze-drying did not exert any considerable effect on β-carotene concentration of fruits, except for mango and watermelon, where significantly (p < 0.05 higher levels were detected in the fresh samples. The results of DPPH (2,2-diphenyl-1-picrylhydrazyl radical scavenging and reducing power assays revealed that fresh samples of starfruit and mango had relatively higher antioxidant activity. In case of linoleic acid peroxidation inhibition measurement, a significant (p < 0.05 but random variation was recorded between the fresh and freeze-dried fruits. Overall, in comparison to β-carotene and ascorbic acid, a good correlation was established between the result of TPC and antioxidant assays, indicating that phenolics might have been the dominant compounds contributing towards the antioxidant activity of the fruits tested.

  9. 柠檬片的低温冻结与真空冷冻干燥工艺研究%Research on the Processing Technology of Freezing and Vacuum Drying of Lemon Slices

    Institute of Scientific and Technical Information of China (English)

    章斌; 丁心; 侯小桢; 秦轶; 邓其海; 高雪; 杨小敏

    2015-01-01

    考察预处理方式、冻结温度(-40、-60、-100℃和液氮滴淋)等因素对柠檬片真空冷冻干燥的影响,并以产品复水率、色差L值、菌落总数、大肠菌群数为指标,探讨冻结方式对柠檬片贮藏过程中的品质变化影响.试验结果表明,柠檬的共晶点在-23℃~-25℃范围内,共熔点在-20℃~-22℃范围内;实验条件下的最佳冻结温度为-100℃,此时的真空干燥时间为11.2 h,贮藏3个月后的色差L值为78.65,且菌落总数低于180 cfu/g,大肠菌群低于3 MPN/g,均达到有关标准要求.%Influence of pretreatment method, freezing temperature (-40,-60,-100 ℃ and liquid nitrogen dripping)on the vacuum freeze drying of lemon slices, as well as taking complex water rate, color difference L value, total number of bacteria colonies and Escherichia coli group as index, effects of freezing method on the quality of lemon slices during storage were explored in this paper. Results showed that co-melting point and eutectic point of lemon were-23℃--25℃,-20℃--22℃respectively. The optimal freezing temperature was-100℃under experimental conditions, and vacuum drying time 11.2 h, color difference L value 78.65, as well as total number bacteria colonies and Escherichia coli group of product was lower than 180 cfu/g and 3 MPN/g respectively after 3 months storage time, which reached relevant standards.

  10. Effect of Freezing on Lyophilization Process Performance and Drug Product Cake Appearance.

    Science.gov (United States)

    Esfandiary, Reza; Gattu, Shravan K; Stewart, John M; Patel, Sajal M

    2016-04-01

    This study highlights the significance of the freezing step and the critical role it can play in modulating process performance and product quality during freeze-drying. For the model protein formulation evaluated, the mechanism of freezing had a significant impact on cake appearance, a potential critical product quality attribute for a lyophilized drug product. Contrary to common knowledge, a freezing step with annealing resulted in 20% increase in primary drying time compared to without annealing. In addition, annealing resulted in poor cake appearance with shrinkage, cracks, and formation of a distinct skin at the top surface of the cake. Finally, higher product resistance (7.5 cm(2).Torr.hr/g) was observed in the case of annealing compared to when annealing was not included (5 cm(2).Torr.hr/g), which explains the longer primary drying time due to reduced sublimation rates. An alternative freezing option using controlled ice nucleation resulted in reduced primary drying time (i.e., 30% reduction compared to annealing) and a more homogenous batch with elegant uniform (i.e., significantly improved) cake appearance. Here, a mechanistic understanding of the distinct differences in cake appearance as a function of freezing mechanism is proposed within the context of ice nucleation temperature, ice crystal growth, and presumed solute distribution within the frozen matrix.

  11. Solidification drug nanosuspensions into nanocrystals by freeze-drying: a case study with ursodeoxycholic acid.

    Science.gov (United States)

    Ma, Yue-Qin; Zhang, Zeng-Zhu; Li, Gang; Zhang, Jing; Xiao, Han-Yang; Li, Xian-Fei

    2016-03-01

    To elucidate the effect of solidification processes on the redispersibility of drug nanocrystals (NC) during freeze-drying, ursodeoxycholic acid (UDCA) nanosuspensions were transformed into UDCA-NC via different solidification process included freezing and lyophilization. The effect of different concentrations of stabilizers and cryoprotectants on redispersibility of UDCA-NC was investigated, respectively. The results showed that the redispersibility of UDCA-NC was RDI-20 °C lyophilization. The hydroxypropylmethylcellulose and PVPK30 were effective to protect UDCA-NC from damage during lyophilization, which could homogeneously adsorb into the surface of NC to prevent from agglomerates. The sucrose and glucose achieved excellent performance that protected UDCA-NC from crystal growth during lyophilization, respectively. It was concluded that UDCA-NC was subjected to agglomeration during solidification transformation, and the degree of agglomeration suffered varied with the type and the amounts of stabilizers used, as well as different solidification conditions. The PVPK30-sucrose system was more effective to protect UDCA-NC from the damage during solidification process.

  12. Protein crowding in solution, frozen and freeze-dried states: small-angle neutron and X-ray scattering study of lysozyme/sorbitol/water systems

    Science.gov (United States)

    Krueger, Susan; Khodadadi, Sheila; Clark, Nicholas; McAuley, Arnold; Cristiglio, Viviana; Theyencheri, Narayanan; Curtis, Joseph; Shalaev, Evgenyi

    2015-03-01

    For effective preservation, proteins are often stored as frozen solutions or in glassy states using a freeze-drying process. However, aggregation is often observed after freeze-thaw or reconstitution of freeze-dried powder and the stability of the protein is no longer assured. In this study, small-angle neutron and X-ray scattering (SANS and SAXS) have been used to investigate changes in protein-protein interaction distances of a model protein/cryoprotectant system of lysozyme/sorbitol/water, under representative pharmaceutical processing conditions. The results demonstrate the utility of SAXS and SANS methods to monitor protein crowding at different stages of freezing and drying. The SANS measurements of solution samples showed at least one protein interaction peak corresponding to an interaction distance of ~ 90 Å. In the frozen state, two protein interaction peaks were observed by SANS with corresponding interaction distances at 40 Å as well as 90 Å. On the other hand, both SAXS and SANS data for freeze-dried samples showed three peaks, suggesting interaction distances ranging from ~ 15 Å to 170 Å. Possible interpretations of these interaction peaks will be discussed, as well as the role of sorbitol as a cryoprotectant during the freezing and drying process.

  13. Production of freeze-dried yeast culture for the brewing of traditional sorghum beer, tchapalo.

    Science.gov (United States)

    N'Guessan, Florent K; Coulibaly, Hermann W; Alloue-Boraud, Mireille W A; Cot, Marlène; Djè, Koffi Marcellin

    2016-01-01

    Freeze-drying is a well-known dehydration method widely used to preserve microorganisms. In order to produce freeze-dried yeast starter culture for the brewing purpose of African sorghum beer, we tested protective agents (sucrose, glucose, glycerol) in combination with support materials (millet, maize, sorghum, and cassava flours) at 1:1 ratio (v/v). The yeast strains Saccharomyces cerevisiae F 12-7 and Candida tropicalis C 0-7 previously isolated from sorghum beer were used in a mixed culture at a ratio of 2:1 (C. tropicalis/S. cerevisiae). After the freeze-drying, the residual water contents were between 0.78 -2.27%, 0.55 -4.09%, and 0.40-2.61%, respectively, with sucrose, glucose and glycerol. The dried yeasts viabilities were between 4.0% and 10.6%. Among the protective agents used, sucrose was found to be the best protectant giving cell viabilities of 8.4-10.6%. Considering the support materials, millet flour was the best support after drying. When the freeze-dried yeast powders were stored at 4°C and room temperature (25-28°C) for up to 3 months, the survival rates were the highest with cassava flour as the support material.

  14. Freeze-drying of proteins with glass-forming oligosaccharide-derived sugar alcohols.

    Science.gov (United States)

    Kadoya, Saori; Fujii, Kahori; Izutsu, Ken-ichi; Yonemochi, Etsuo; Terada, Katsuhide; Yomota, Chikako; Kawanishi, Toru

    2010-04-15

    Physical properties and protein-stabilizing effects of sugar alcohols in frozen aqueous solutions and freeze-dried solids were studied. Various frozen sugar alcohol solutions showed a glass transition of the maximally freeze-concentrated phase at temperatures (T(g)'s) that depended largely on the solute molecular weights. Some oligosaccharide-derived sugar alcohols (e.g., maltitol, lactitol, maltotriitol) formed glass-state amorphous cake-structure freeze-dried solids. Microscopic observation of frozen maltitol and lactitol solutions under vacuum (FDM) indicated onset of physical collapse at temperatures (T(c)) several degrees higher than their T(g)'s. Freeze-drying of pentitols (e.g., xylitol) and hexitols (e.g., sorbitol, mannitol) resulted in collapsed or crystallized solids. The glass-forming sugar alcohols prevented activity loss of a model protein (LDH: lactate dehydrogenase) during freeze-drying and subsequent storage at 50 degrees C. They also protected bovine serum albumin (BSA) from lyophilization-induced secondary structure perturbation. The glass-forming sugar alcohols showed lower susceptibility to Maillard reaction with co-lyophilized L-lysine compared to reducing and non-reducing disaccharides during storage at elevated temperature. Application of the oligosaccharide-derived sugar alcohols as alternative stabilizers in lyophilized protein formulations was discussed. Copyright 2010 Elsevier B.V. All rights reserved.

  15. Vitamins, fatty acids, and antioxidant capacity stability during storage of freeze-dried human milk.

    Science.gov (United States)

    Lozano, Blanca; Castellote, Ana Isabel; Montes, Rosa; López-Sabater, M Carmen

    2014-09-01

    Although freezing is the most common method used to preserve human milk, nutritional and immunological components may be lost during storage. Freeze-drying could increase the shelf life of human milk, while preserving its original characteristics. Seventy-two samples of freeze-dried human milk were stored for different periods of time, up to a maximum of 3 months, at 4 °C or 40 °C. Vitamin C, tocopherols, antioxidant capacity, and fatty acids composition were analyzed. A new HILIC-UHPLC method improving vitamin C determination was also validated. Ascorbic acid and total vitamin C concentrations significantly decreased at both temperatures, while antioxidant capacity only decreased at 40 °C. Fatty acids composition and both γ-tocopherol and δ-tocopherol contents remained unaltered. The stability after storage of freeze-dried milk was higher than that reported for frozen or fresh milk indicating that freeze-drying is a promising option to improve the preservation of human milk in banks.

  16. The role of protein modifications in senescence of freeze-dried Acetobacter senegalensis during storage

    Science.gov (United States)

    2014-01-01

    Background Loss of viability is one of the most important problems during starter culture production. Previous research has mostly focused on the production process of bacterial starters, but there are few studies about cellular protein deterioration causing cell defectiveness during storage. In the present study, we investigated the influence of storage temperature (−21, 4, 35°C) on the cellular protein modifications which may contribute to the senescence of freeze-dried Acetobacter senegalensis. Results Heterogeneous populations composed of culturable cells, viable but non-culturable cells (VBNC) and dead cells were generated when freeze-dried cells were kept at −21 and 4°C for 12 months whereas higher storage temperature (35°C) mainly caused death of the cells. The analysis of stored cell proteome by 2D-DiGE demonstrated a modified pattern of protein profile for cell kept at 4 and 35°C due to the formation of protein spot trains and shift of Isoelectric point (pI). Quantification of carbonylated protein by ELISA showed that the cells stored at 4 and 35°C had higher carbonylated protein contents than fresh cells. 2D-DiGE followed by Western blotting also confirmed the carbonylation of cellular proteins involved in translation process and energy generation. The auto-fluorescent feature of cells kept at 35°C increased significantly which may be an indication of protein glycation during storage. In addition, the percentage of cellular unsaturated fatty acid and the solubility of cellular proteins decreased upon storage of cells at higher temperature suggesting that peroxidation of fatty acids and possibly protein lipidation and oxidation occurred. Conclusions High storage temperature induces some deteriorative reactions such as protein oxidation, lipidation and glycation which may cause further protein modifications like pI-shift, and protein insolubility. These modifications can partly account for the changes in cell viability. It can also be deduced

  17. Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kai [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Ruixin [Institute of Medical Equipment, Academy of Military and Medical Sciences, No. 106, Wandong Street, Hedong District, Tianjin 300000 (China); Jiang, Wenxue, E-mail: jiangortholivea@sina.cn [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Sun, Yufu [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Hui [Tianjin Medical University General Hospital, No. 154 Anshan Road, Tianjin, TJ 300052 (China)

    2016-09-02

    In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young’s modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. - Highlights: • Silk fibroin/collagen was fabricated using 3D printing. • Physical characterization and Cell compatibility were compared. • 3D printed scaffold exhibited better overall performance.

  18. Identification of Components or Fractions Associated with Adverse Changes in Freeze Dried Chicken and Pork during Storage

    Science.gov (United States)

    1978-06-01

    of glucose by yeast fermentation . Food Techmol. 9: 290 (1955). 12 Fleming, I. E. and H. F. Pegler. The determination of glucose in the pre.- ence of...Amerine et al., 1965). 17 Osman, 0. A. H. and R. E. Morse. Preparation and storage characteristics of freeze dried sausages . I. Formulation and...processing of comminuted sausages (frankfurters). Food Technol. 14: 37 (Abstract) (1960). 1Amerine, M. A., R. M. Pangborn, and E. P. Roessler. Principles of

  19. Effect of the aerated structure on selected properties of freeze-dried hydrocolloid gels

    Science.gov (United States)

    Ciurzyńska, Agnieszka; Lenart, Andrzej

    2016-01-01

    The ability to create diverse structures and studies on the effect of the aerated structure on selected properties with the use of freeze-dried gels may provide knowledge about the properties of dried foods. Such gels can be a basis for obtaining innovative food products. For the gel preparation, 3 types of hydrocolloids were used: low-methoxyl pectin, a mixture of xanthan gum and locust-bean gum, and a mixture of xanthan gum and guar gum. Gels were aerated for 3 and 7 min, frozen at a temperature of -45°C 2 h-1, and freeze-dried at a temperature of 30°C. For the samples obtained, structure, porosity, shrinkage, rehydration, and colour were investigated. It was shown that the type of the hydrocolloid and aeration time influence the structure of freeze-dried gels, which determines such properties of samples as porosity, shrinkage, density, rehydration, and colour. The bigger pores of low-methoxyl pectin gels undergo rehydration in the highest degree. The delicate and aerated structure of gels with the mixture of xanthan gum and locust-bean gum was damaged during freeze-drying and shrinkage exhibited the highest value. Small pores of samples with the mixture of xanthan gum and guar gum were responsible for the lower rehydration properties, but the highest porosity value contributed to the highest lightness value.

  20. Development of a nanosuspension for iv administration: From miniscale screening to a freeze dried formulation.

    Science.gov (United States)

    Frank, Kerstin J; Boeck, Georg

    2016-05-25

    The aim was to develop a nanosuspension of the poorly soluble BI XX. The nanosuspension is intended for intravenous (iv) administration in preclinical studies and should not cause any unwanted side effects. Thus, only stabilizers that are accepted for iv application should be used and isotonicity, euhydria and the absence of living microorganisms were targeted. Suspensions were prepared in a ball-mill (mixing mill MM 400 from Retsch). There were various vials used as containers; HPLC-vials were used for the small scale screening of stabilizers and injection vials for preparation of larger quantities of the nanosuspensions. Particle size distribution was analyzed by laser diffraction measurement (Mastersizer 2000). Lyophilization was used for processing of the suspensions (Christ freeze dryer). Stable nanosuspensions (d90 remained nanosuspension. Various FDA accepted excipients were identified which resulted in stable nanosuspensions of BI XX. The most stable formulation was successfully freeze dried. It was proven that milling in the ball-mill decreases the presence of living microorganisms.

  1. Validation of a multipoint near-infrared spectroscopy method for in-line moisture content analysis during freeze-drying.

    Science.gov (United States)

    Kauppinen, Ari; Toiviainen, Maunu; Lehtonen, Marko; Järvinen, Kristiina; Paaso, Janne; Juuti, Mikko; Ketolainen, Jarkko

    2014-07-01

    This study assessed the validity of a multipoint near-infrared (NIR) spectroscopy method for in-line moisture content analysis during a freeze-drying process. It is known that the moisture content affects the stability of a freeze-dried product and hence it is a major critical quality attribute. Therefore assessment of the validity of an analytical method for moisture content determination is vital to ensure the quality of the final product. An aqueous sucrose solution was used as the model formulation of the study. The NIR spectra were calibrated to the moisture content using partial least squares (PLS) regression with coulometric Karl Fischer (KF) titration as the reference method. Different spectral preprocessing methods were compared for the PLS models. A calibration model transfer protocol was established to enable the use of the method in the multipoint mode. The accuracy profile was used as a decision tool to determine the validity of the method. The final PLS model, in which NIR spectra were preprocessed with standard normal variate transformation (SNV), resulted in low root mean square error of prediction value of 0.04%-m/v, i.e. evidence of sufficient overall accuracy of the model. The validation results revealed that the accuracy of the model was acceptable within the moisture content range 0.16-0.70%-m/v that is specific for the latter stages of the freeze-drying process. In addition, the results demonstrated the method's reliable in-process performance and robustness. Thus, the multipoint NIR spectroscopy method was proved capable of providing in-line evaluation of moisture content and it is readily available for use in laboratory scale freeze-drying research and development. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Effect of different disaccharides on the integrity and fertilising ability of freeze-dried boar spermatozoa: a preliminary study.

    Science.gov (United States)

    Garcia, A; Gil, L; Malo, C; Martinez, F; Kershaw-Young, C; de Blas, I

    2014-01-01

    Freeze-drying spermatozoa is a developing technique that facilitates semen storage and transport. However, freeze-dried sperm exhibits impaired DNA integrity, which is associated with reduced fertilizing ability. Boar spermatozoa were freeze-dried in three different freeze-drying EDTA buffers with trehalose (75mM) and lactose (75mM) (EDTA-TL), (2) with sucrose (75mM) and lactose (75mM) (EDTA-SL) or just lactose (150mM) (EDTA-LL) using two freeze-drying protocols. In experiment 1 a one-step protocol was used and in experiment 2 a two-steps protocol was used. Spermatozoa were stored in1.5 mL cryo-tubes and 1.5 mL glass ampules at both 16 degree C and 25 degree C for 1 month. Successfully freeze-dried spermatozoa were stained with acridine-orange to assess chromatin stability. Freeze-drying was most successful when the 2-step protocol was used (experiment 2). Chromatin stability was greater in samples stored in glass ampules compared to cryo tubes. Chromatin stability was also greater in samples freeze-dried in EDTA-LL compared to EDTA-SL or EDTA-TL buffers. Spermatozoa freeze-dried in EDTA-LL and stored for 14 and 28 days at either 16 degree C or 25 degree C were utilized for ICSI. Two pronuclear formation wasgreatest using spermatozoa stored at 25 degree C (69.23%) and for 28 days (50%). Although 16 degree C spermatozoa samples had better stable chromatin, 25 degree C spermatozoa samples offered better two pronuclear formation results. In conclusion, boar spermatozoa freeze-dried using media containing disaccharides exhibit high chromatin stability and are able to fertilise oocytes following ICSI. Disaccharides may therefore advance the development of freeze-drying techniques for spermatozoa enabling ease of sperm storage and transportation.

  3. Near-Infrared Imaging for High-Throughput Screening of Moisture-Induced Changes in Freeze-Dried Formulations

    DEFF Research Database (Denmark)

    Trnka, Hjalte; Palou, Anna; Panouillot, Pierre Emanuel

    2014-01-01

    formulations were freeze-dried in well plates. Samples were imaged with a NIR hyperspectral camera after freeze-drying and upon storage. On the basis of Karl Fischer titration reference values, a univariate quantification model was constructed and used to visualize the distribution of water within freeze......Evaluation of freeze-dried biopharmaceutical formulations requires careful analysis of multiple quality attributes. The aim of this study was to evaluate the use of near-infrared (NIR) imaging for fast analysis of water content and related physical properties in freeze-dried formulations. Model...... drying was observed within the samples after 3 days of storage. Further investigations with X-ray powder diffraction confirmed this local drying to be related to crystallization of sucrose. The combination of fast analysis of water content and spatial solid-state information makes NIR imaging a powerful...

  4. Growth and Freeze-Drying Optimization of Bifidobacterium crudilactis

    OpenAIRE

    Tanimomo, Jean; Delcenserie, Véronique; Taminiau, Bernard; Daube, Georges; Saint-Hubert, Catherine; Durieux, Alain

    2016-01-01

    Bifidobacterium crudilactis FR62/b/3 belongs to a new population of bifidobacteria isolated from raw milk and raw milk cheese. The objective of this work was to study the large scale culture of the stain and its stability in a dry formulation. Growth rate of Bifidobacterium crudilactis FR62/b/3 was optimal at a pH of 5.0 and a temperature of 37˚C. At a temperature growth of 33˚C and a pH of 5.0, the stationary phase was reached after 22 h, the viable cell number and the mean dry b...

  5. Immunisation of Sheep with Bovine Viral Diarrhoea Virus, E2 Protein Using a Freeze-Dried Hollow Silica Mesoporous Nanoparticle Formulation.

    Directory of Open Access Journals (Sweden)

    Donna Mahony

    Full Text Available Bovine viral diarrhoea virus 1 (BVDV-1 is arguably the most important viral disease of cattle. It is associated with reproductive, respiratory and chronic diseases in cattle across the world. In this study we have investigated the capacity of the major immunological determinant of BVDV-1, the E2 protein combined with hollow type mesoporous silica nanoparticles with surface amino functionalisation (HMSA, to stimulate immune responses in sheep. The current work also investigated the immunogenicity of the E2 nanoformulation before and after freeze-drying processes. The optimal excipient formulation for freeze-drying of the E2 nanoformulation was determined to be 5% trehalose and 1% glycine. This excipient formulation preserved both the E2 protein integrity and HMSA particle structure. Sheep were immunised three times at three week intervals by subcutaneous injection with 500 μg E2 adsorbed to 6.2 mg HMSA as either a non-freeze-dried or freeze-dried nanoformulation. The capacity of both nanovaccine formulations to generate humoral (antibody and cell-mediated responses in sheep were compared to the responses in sheep immunisation with Opti-E2 (500 μg together with the conventional adjuvant Quil-A (1 mg, a saponin from the Molina tree (Quillaja saponira. The level of the antibody responses detected to both the non-freeze-dried and freeze-dried Opti-E2/HMSA nanoformulations were similar to those obtained for Opti-E2 plus Quil-A, demonstrating the E2 nanoformulations were immunogenic in a large animal, and freeze-drying did not affect the immunogenicity of the E2 antigen. Importantly, it was demonstrated that the long term cell-mediated immune responses were detectable up to four months after immunisation. The cell-mediated immune responses were consistently high in all sheep immunised with the freeze-dried Opti-E2/HMSA nanovaccine formulation (>2,290 SFU/million cells compared to the non-freeze-dried nanovaccine formulation (213-500 SFU/million cells

  6. Microencapsulation of Purified Amylase Enzyme from Pitaya (Hylocereus polyrhizus Peel in Arabic Gum-Chitosan using Freeze Drying

    Directory of Open Access Journals (Sweden)

    Mehrnoush Amid

    2014-03-01

    Full Text Available Amylase is one of the most important enzymes in the world due to its wide application in various industries and biotechnological processes. In this study, amylase enzyme from Hylocereus polyrhizus was encapsulated for the first time in an Arabic gum-chitosan matrix using freeze drying. The encapsulated amylase retained complete biocatalytic activity and exhibited a shift in the optimum temperature and considerable increase in the pH and temperature stabilities compared to the free enzyme. Encapsulation of the enzyme protected the activity in the presence of ionic and non-ionic surfactants and oxidizing agents (H2O2 and enhanced the shelf life. The storage stability of amylase is found to markedly increase after immobilization and the freeze dried amylase exhibited maximum encapsulation efficiency value (96.2% after the encapsulation process. Therefore, the present study demonstrated that the encapsulation of the enzyme in a coating agent using freeze drying is an efficient method to keep the enzyme active and stable until required in industry.

  7. Microencapsulation of purified amylase enzyme from pitaya (Hylocereus polyrhizus) peel in Arabic gum-chitosan using freeze drying.

    Science.gov (United States)

    Amid, Mehrnoush; Manap, Yazid; Zohdi, Nor Khanani

    2014-03-24

    Amylase is one of the most important enzymes in the world due to its wide application in various industries and biotechnological processes. In this study, amylase enzyme from Hylocereus polyrhizus was encapsulated for the first time in an Arabic gum-chitosan matrix using freeze drying. The encapsulated amylase retained complete biocatalytic activity and exhibited a shift in the optimum temperature and considerable increase in the pH and temperature stabilities compared to the free enzyme. Encapsulation of the enzyme protected the activity in the presence of ionic and non-ionic surfactants and oxidizing agents (H₂O₂) and enhanced the shelf life. The storage stability of amylase is found to markedly increase after immobilization and the freeze dried amylase exhibited maximum encapsulation efficiency value (96.2%) after the encapsulation process. Therefore, the present study demonstrated that the encapsulation of the enzyme in a coating agent using freeze drying is an efficient method to keep the enzyme active and stable until required in industry.

  8. Parameter Sensitivity of the Microdroplet Vacuum Freezing Process

    Directory of Open Access Journals (Sweden)

    Zhijun Zhang

    2015-01-01

    Full Text Available The vacuum freezing process of microdroplets (1 mm. Pressure and droplet diameter have an effect on cooling and freezing stages, but initial temperature only affects the cooling stage. The thermal conductivity coefficient kl affected the cooling stage, whereas ki affected the freezing stage. Heat capacity Cl affected the cooling stage, but Ci has virtually no effect on all stages. The actual latent heat of freezing ΔH was also affected. Higher density corresponds to lower cooling rate in the cooling stage.

  9. On the use of tert-butanol/water cosolvent systems in production and freeze-drying of poly-ε-caprolactone nanoparticles.

    Science.gov (United States)

    Zelenková, Tereza; Barresi, Antonello A; Fissore, Davide

    2015-01-01

    This work deals with the use of a water/tert-butyl alcohol (TBA) system in the manufacturing process of poly-ε-caprolactone (PCL) nanoparticles, namely in the synthesis stage, using the solvent displacement method in a confined impinging jet mixer (CIJM), and in the following freeze-drying stage. The experimental investigation evidenced that the nanoparticles size is significantly reduced with respect to the case where acetone is the solvent. Besides, the solvent evaporation step is not required before freeze-drying as TBA is fully compatible with the freeze-drying process. The effect of initial polymer concentration, flow rate, water to TBA flow rate ratio, and quench volumetric ratio on the mean nanoparticles size was investigated, and a simple equation was proposed to relate the mean nanoparticles size to these operating parameters. Then, freeze-drying of the nanoparticles suspensions was studied. Lyoprotectants (sucrose and mannitol) and steric stabilizers (Cremophor EL and Poloxamer 388) have to be used to avoid nanoparticles aggregation, thus preserving particle size distribution and mean nanoparticles size. Their effect, as well as that of the heating shelf temperature, has been investigated by means of statistical techniques, with the goal to identify which of these factors, or combination of factors, plays the key role in the nanoparticles size preservation at the end of the freeze-drying process.

  10. Size and molecular flexibility of sugars determine the storage stability of freeze-dried proteins

    NARCIS (Netherlands)

    Tonnis, W. F.; Mensink, M. A.; de Jager, A.; Maarschalk, K. van der Voort; Frijlink, H. W.; Hinrichs, W. L. J.

    2015-01-01

    Protein-based biopharmaceuticals are generally produced as aqueous solutions and stored refrigerated to obtain sufficient shelf life. Alternatively, proteins may be freeze-dried in the presence of sugars to allow storage stability at ambient conditions for prolonged periods. However, to act as a sta

  11. Fuzzy Logic-based expert system for evaluating cake quality of freeze-dried formulations

    DEFF Research Database (Denmark)

    Trnka, Hjalte; Wu, Jian-Xiong; van de Weert, Marco

    2013-01-01

    Freeze-drying of peptide and protein-based pharmaceuticals is an increasingly important field of research. The diverse nature of these compounds, limited understanding of excipient functionality, and difficult-to-analyze quality attributes together with the increasing importance of the biosimilar...

  12. TEMPERATURE-DEPENDENCE OF WATER TRANSPORT INTO THE MINERALIZED MATRIX OF FREEZE-DRIED HUMAN DENTIN

    NARCIS (Netherlands)

    VANDERGRAAF, ER; TENBOSCH, JJ

    1991-01-01

    Ten dentine sections cut perpendicular to the dentinal tubules from human mature non-carious third molars, were freeze-dried and then rehydrated by immersion in water at four temperatures, 10, 25, 40 and 70-degrees-C. The uptake of water by the sections was assessed as a function of rehydration time

  13. Optimization of Freeze Drying Conditions for Purified Pectinase from Mango (Mangifera indica cv. Chokanan Peel

    Directory of Open Access Journals (Sweden)

    Abdul Manap Mohd Yazid

    2012-03-01

    Full Text Available Response surface methodology (RSM along with central composite design (CCD was applied to optimize the freeze drying conditions for purified pectinase from mango (Mangifera indica cv. Chokanan peel. The effect of pectinase content (−2.66, 62.66 mg/mL, Arabic gum (−1.21, 10.21%, w/v, and maltodextrin (0.73, 7.26%, w/v as independent variables on activity, yield, and storage stability of freeze-dried enzyme was evaluated. Storage stability of pectinase was investigated after one week at 4 °C and yield percentage of the enzyme after encapsulation was also determined. The independent variables had the most significant (p < 0.05 effect on pectinase activity and yield of the enzyme. It was observed that the interaction effect of Arabic gum and maltodextrin improved the enzymatic properties of freeze-dried pectinase. The optimal conditions for freeze-dried pectinase from mango peel were obtained using 30 mg/mL of pectinase content, 4.5 (%, w/v of Arabic gum, and 4 (%, w/v of maltodextrin. Under these conditions, the maximum activity (11.12 U/mL, yield (86.4% and storage stability (84.2% of encapsulated pectinase were achieved.

  14. References on Compression of Freeze-Dried Foods

    Science.gov (United States)

    1978-08-01

    and 38 Pineapple Cheese , Gouda 18 Cheese , loman Cheese Sauce Cheese Sauce, Beef *n 2, 8 Cheese Sauce, Tuna in 8 Obeea with Vegetables 8and BaconMilk...Chocolate Beverage, (3) Cream of Mushroom Soup, (4) German Potato Salad, (5) Cole Slaw, (6) Pineapple-Cottage Cheese Salad (7) Welsh Rarebit, (8) Crab...dried fruit juices. Japan 342/66. Jokay, L. 1964. Dehydrated, carbohydrate-enriched, palatable cheese - based food bar. US Patent 3,121,014. 38 Jones

  15. Preparation and Characterization of Solid Dispersions of Artemether by Freeze-Dried Method

    Directory of Open Access Journals (Sweden)

    Muhammad Tayyab Ansari

    2015-01-01

    Full Text Available Solid dispersions of artemether and polyethylene glycol 6000 (PEG6000 were prepared in ratio 12 : 88 (group-1. Self-emulsified solid dispersions of artemether were prepared by using polyethylene glycol 6000, Cremophor-A25, olive oil, Transcutol, and hydroxypropyl methylcellulose (HPMC in ratio 12 : 75 : 5 : 4 : 2 : 2, respectively (group-2. In third group, only Cremophor-A25 was replaced with Poloxamer 188 compared to group-2. The solid dispersions and self-emulsified solid dispersions were prepared by physical and freeze dried methods, respectively. All samples were characterized by X-ray diffraction, attenuated total reflectance Fourier transform infrared spectroscopy, differential scanning calorimeter, scanning electron microscopy, and solubility, dissolution, and stability studies. X-ray diffraction pattern revealed artemether complete crystalline, whereas physical mixture and freeze-dried mixture of all three groups showed reduced peak intensities. In attenuated total reflectance Fourier transform infrared spectroscopy spectra, C–H stretching vibrations of artemether were masked in all prepared samples, while C–H stretching vibrations were representative of polyethylene glycol 6000, Cremophor-A25, and Poloxamer 188. Differential scanning calorimetry showed decreased melting endotherm and increased enthalpy change (ΔH in both physical mixture and freeze-dried mixtures of all groups. Scanning electron microscopy of freeze-dried mixtures of all samples showed glassy appearance, size reduction, and embedment, while their physical mixture showed size reduction and embedment of artemether by excipients. In group-1, solubility was improved up to 15 times, whereas group-2 showed up to 121 times increase but, in group-3, when Poloxamer 188 was used instead of Cremophor-A25, solubility of freeze-dried mixtures was increased up to 135 times. In fasted state simulated gastric fluid at pH 1.6, the dissolution of physical

  16. Effect of ultrasound and blanching pretreatments on polyacetylene and carotenoid content of hot air and freeze dried carrot discs.

    Science.gov (United States)

    Rawson, A; Tiwari, B K; Tuohy, M G; O'Donnell, C P; Brunton, N

    2011-09-01

    The effect of ultrasound and blanching pretreatments on polyacetylene (falcarinol, falcarindiol and falcarindiol-3-acetate) and carotenoid compounds of hot air and freeze dried carrot discs was investigated. Ultrasound pretreatment followed by hot air drying (UPHD) at the highest amplitude and treatment time investigated resulted in higher retention of polyacetylenes and carotenoids in dried carrot discs than blanching followed by hot air drying. Freeze dried samples had a higher retention of polyacetylene and carotenoid compounds compared to hot air dried samples. Color parameters were strongly correlated with carotenoids (p<0.05). This study shows that ultrasound pretreatment is a potential alternative to conventional blanching treatment in the drying of carrots.

  17. Effects of sugar alcohol and proteins on the survival of Lactobacillus bulgaricus LB6 during freeze drying

    Directory of Open Access Journals (Sweden)

    He Chen

    2015-06-01

    Full Text Available Background. Lactobacillus bulgaricus LB6 is a bacterium which was selected in the commercial yoghurt with high angiotensin converting enzyme (ACE inhibitory activity. Preparation of concentrated starter cultures via freeze drying is of practical importance to dairy and food industries. Material and methods. We optimized the optimal sugar alcohol and proteins for Lactobacillus bulgaricus LB6 during the process of freeze drying using a Plackett-Burman design. In our initial tests survival rate and the number of viable cells were associated with the type of lyoprotectant used and so our optimization protocol focused on increasing survival rate. Substances that had previously had a protective effect during freeze drying were investigated, for example: mannitol, sorbitol, xylitol, meso-erythritol, lactitol, whey protein isolate 90, bovine serum albumin, and whey protein concentrate 80 and soy protein isolate 70. Results. We found that the optimum sugar alcohol and proteins for survival of Lactobacillus bulgaricus LB6 were whey protein concentrate (p = 0.0040 for survival rate, xylitol (p = 0.0067 for survival rate and sorbitol (p = 0.0073 for survival rate, they showed positive effect (whey protein concentrate and sorbitol or negative effect (xylitol. Discussion. The effectiveness of three chosen sugar alcohols and protein implied that they could be used as lyoprotectant for Lactobacillus bulgaricus LB6 in the further research, the optimal composition of sugar alcohol and protein for the lyoprotectant use must be established.

  18. Building the Method to Determine the Rate of Freezing Water in Penaeus monodon of the Freezing Process

    Directory of Open Access Journals (Sweden)

    Nguyen Tan Dzung

    2012-10-01

    Full Text Available The method of determination the rate of freezing water in Penaeus monodon of freezing process was established on base the equation of energy balance in warming up process Penaeus monodon after freezing to determine specific heat of Penaeus monodon. The result obtained was built the mathematical model (19 to determine the rate of freezing water according to the freezing temperature of Penaeus monodon. The results indicated that when water was completely frozen (ω = 1 or 100%, the optimal freezing temperature of Penaeus monodon was-22.00°C.

  19. Multivariate analysis of phenol in freeze-dried and spray-dried insulin formulations by NIR and FTIR.

    Science.gov (United States)

    Maltesen, Morten Jonas; Bjerregaard, Simon; Hovgaard, Lars; Havelund, Svend; van de Weert, Marco; Grohganz, Holger

    2011-06-01

    Dehydration is a commonly used method to stabilise protein formulations. Upon dehydration, there is a significant risk the composition of the formulation will change especially if the protein formulation contains volatile compounds. Phenol is often used as excipient in insulin formulations, stabilising the insulin hexamer by changing the secondary structure. We have previously shown that it is possible to maintain this structural change after drying. The aim of this study was to evaluate the residual phenol content in spray-dried and freeze-dried insulin formulations by Fourier transform infrared (FTIR) spectroscopy and near infrared (NIR) spectroscopy using multivariate data analysis. A principal component analysis (PCA) and partial least squares (PLS) projections were used to analyse spectral data. After drying, there was a difference between the two drying methods in the phenol/insulin ratio and the water content of the dried samples. The spray-dried samples contained more water and less phenol compared with the freeze-dried samples. For the FTIR spectra, the best model used one PLS component to describe the phenol/insulin ratio in the powders, and was based on the second derivative pre-treated spectra in the 850-650 cm(-1) region. The best PLS model based on the NIR spectra utilised three PLS components to describe the phenol/insulin ratio and was based on the standard normal variate transformed spectra in the 6,200-5,800 cm(-1) region. The root mean square error of cross validation was 0.69% and 0.60% (w/w) for the models based on the FTIR and NIR spectra, respectively. In general, both methods were suitable for phenol quantification in dried phenol/insulin samples.

  20. Freeze-dried polymer-coated quantum dots for perspective biomedical application

    Science.gov (United States)

    Goftman, Valentina V.; Gaynbuch, Anna V.; Panfilova, Elizaveta V.; Khlebtsov, Boris N.; Goryacheva, Irina Y.

    2015-03-01

    Freeze-drying as known as lyophilization has been considered as a possible technique to improve the long-term stability of colloidal luminescent quantum dots (QDs) for perspective biomedical application. The paper describes synthesis of biocompatible CdSe-based core/shell QDs and discusses their optical and physical properties before and after freezedrying. Importantly, the dried nanoparticles can be stored for a long time under usual conditions and then can easily be redisperse in water at a desired concentration without such hard manipulations as sonication or heating. In this work two PEG-amine derivatives were applied for QDs pegylation: monoamine Jeffamine M1000 and diamine JeffamineED-2003. The use of different Jeffamines allows us to obtain QDs with different length of PEG chains and different ζ-potential. The influence of polymer composition on optical properties of the nanocrystals and on their stability after freeze-drying was studied.

  1. Model-Based PAT for Quality Management in Pharmaceuticals Freeze-Drying: State of the Art

    Science.gov (United States)

    Fissore, Davide

    2017-01-01

    Model-based process analytical technologies can be used for the in-line control and optimization of a pharmaceuticals freeze-drying process, as well as for the off-line design of the process, i.e., the identification of the optimal operating conditions. This paper aims at presenting the state of the art in this field, focusing, particularly, on three groups of systems, namely, those based on the temperature measurement (i.e., the soft sensor), on the chamber pressure measurement (i.e., the systems based on the test of pressure rise and of pressure decrease), and on the sublimation flux estimate (i.e., the tunable diode laser absorption spectroscopy and the valveless monitoring system). The application of these systems for in-line process optimization (e.g., using a model predictive control algorithm) and to get a true quality by design (e.g., through the off-line calculation of the design space of the process) is presented and discussed. PMID:28224123

  2. Solubility enhancement of BCS Class II drug by solid phospholipid dispersions: Spray drying versus freeze-drying.

    Science.gov (United States)

    Fong, Sophia Yui Kau; Ibisogly, Asiye; Bauer-Brandl, Annette

    2015-12-30

    The poor aqueous solubility of BCS Class II drugs represents a major challenge for oral dosage form development. Using celecoxib (CXB) as model drug, the current study adopted a novel solid phospholipid nanoparticle (SPLN) approach and compared the effect of two commonly used industrial manufacturing methods, spray- and freeze-drying, on the solubility and dissolution enhancement of CXB. CXB was formulated with Phospholipoid E80 (PL) and trehalose at different CXB:PL:trehalose ratios, of which 1:10:16 was the optimal formulation. Spherical amorphous SPLNs with average diameters spray-drying; while amorphous 'matrix'-like structures of solid PL dispersion with larger particle sizes were prepared by freeze-drying. Formulations from both methods significantly enhanced the dissolution rates, apparent solubility, and molecularly dissolved concentration of CXB in phosphate buffer (PBS, pH 6.5) and in biorelevant fasted state simulated intestinal fluid (FaSSIF, pH 6.5) (pspray-dried SPLNs had a larger enhancement in apparent solubility (29- to 132-fold) as well as molecular solubility (18-fold) of CXB at equilibrium (pspray-dried SPLNs to attain 'true' supersaturation state makes them a promising approach for bioavailability enhancement of poorly soluble drugs.

  3. Preparation of redispersible liposomal dry powder using an ultrasonic spray freeze-drying technique for transdermal delivery of human epithelial growth factor

    Directory of Open Access Journals (Sweden)

    Yin F

    2014-03-01

    Full Text Available Fei Yin,1 Shiyan Guo,2 Yong Gan,2 Xinxin Zhang21Department of Pharmacy, Liaoning Cancer Hospital and Institute, Shenyang, 2Shanghai Institute of Materia Medica, Chinese Academy of Science, Shanghai, People's Republic of ChinaAbstract: In this work, an ultrasonic spray freeze-drying (USFD technique was used to prepare a stable liposomal dry powder for transdermal delivery of recombinant human epithelial growth factor (rhEGF. Morphology, particle size, entrapment efficiency, in vitro release, and skin permeability were systematically compared between rhEGF liposomal dry powder prepared using USFD and that prepared using a conventional lyophilization process. Porous and spherical particles with high specific area were produced under USFD conditions. USFD effectively avoided formation of ice crystals, disruption of the bilayer structure, and drug leakage during the liposome drying process, and maintained the stability of the rhEGF liposomal formulation during storage. The reconstituted rhEGF liposomes prepared from USFD powder did not show significant changes in morphology, particle size, entrapment efficiency, or in vitro release characteristics compared with those of rhEGF liposomes before drying. Moreover, the rhEGF liposomal powder prepared with USFD exhibited excellent enhanced penetration in ex vivo mouse skin compared with that for powder prepared via conventional lyophilization. The results suggest that ultrasonic USFD is a promising technique for the production of stable protein-loaded liposomal dry powder for application to the skin.Keywords: spray freeze-drying, recombinant human epithelial growth factor, liposomes, skin permeability, transdermal drug delivery

  4. Freeze granulation for the processing of silicon nitride ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Lyckfeldt, O. [Swedish Ceramic Inst., Goeteborg (Sweden); Rundgren, K. [Permascand AB, Ljungaverk (Sweden); Sjoestedt, M. [PowderPro HB, Hisings Backa (Sweden)

    2004-07-01

    Freeze granulation (LS-2, PowderPro HB, Sweden) has been demonstrated as a favourable alternative to conventional granulation methods (spray drying, sieve granulation etc) in the production of granules for the pressing of high-performance ceramic powders. Freeze granulation/freeze drying prevents the migration of pressing aids or particle fines to the granule surface, as is the case in spray drying. This ensures granule homogeneity and an easy breakdown of granules during pressing. This, in turn, results in defect minimisation and optimal conditions for the sintering and the development of the desired material properties. In this study silicon nitride materials have been produced using freeze granulation, pressing and sintering to validate the performance. Materials with competitive properties were manufactured based on medium-cost, direct-nitrided powders (SicoNide P95, Permascand AB, Sweden), various pressing and sintering aid compositions as well as various pressing and sintering schedules. MgO vs Fe{sub 2}O{sub 3} as sintering aid, PEG vs PVA as binder and higher pressure at the initial uniaxial pressing were found to promote the sintering performance. (orig.)

  5. FREEZE DRYING OF KIWI (ACTINIDIA DELICIOSA PUREE AND THE POWDER PROPERTIES

    Directory of Open Access Journals (Sweden)

    Gulsah Calıskan

    2015-09-01

    Full Text Available In this study, it was intended to investigate the production of freeze dried kiwi (Actinidia deliciosa puree in the form of powder that can be used as a natural alternative to synthetic additives used in food products such as pudding, instant tea, and sauces for improving their flavour. In order to obtain the powder product, kiwi puree as plain and with maltodextrin (Dextrose Equivalence of 10-12, as 10 % by weight addition were freeze dried. Drying behaviour of plain kiwi puree and kiwi puree with MD were explained by Logarithmic model (R2=0.994, RMSE=0.024, χ2=0.0008 and Wang and Singh model (R2=0.999, RMSE=0.012, χ2=0.0002, respectively. The effective moisture diffusivity (Deff value was calculated as 7.3x10−10 m2/s and it was observed that it was not affected by the addition of MD. The vitamin C content of fresh kiwi fruit was evaluated as 66.3 mg/100 g kiwi and there was a loss of 17.1% for plain and 19.8% for MD containing powders respectively after freeze drying. It was also observed that, the addition of maltodextrin decreased cohesiveness, on the other hand, increased bulk and tapped densities, average time values for wettability and solubility, and glass transition temperature of the powder products.

  6. The effect of variety and maturity on the quality of freeze-dried carrots. The effect of microwave blanching on the nutritional and textural quality of freeze-dried spinach

    Science.gov (United States)

    1979-01-01

    Using carrots, the quality of freeze-dried products was studied to determine the optimum varieties and maturation stages for quality attributes such as appearance, flavor, texture, and nutritive value. The quality of freeze-dried carrots is discussed in terms of Gardner color, alcohol insoluble solids, viscosity, and core/cortex ratio. Also, microwave blanching of freeze-dried spinach was studied to determine vitamin interrelationships, anatomical changes, and oxidative deteriorations in terms of preprocessing microwave treatments. Statistical methods were employed in the gathering of data and interpretation of results in both studies.

  7. Physical Chemistry of the Freezing Process of Atmospheric Aqueous Drops.

    Science.gov (United States)

    Bogdan, Anatoli; Molina, Mario J

    2017-04-27

    In supercooled aqueous solutions, ice nucleation is the initial stage of the freezing process. In this paper, we present experimental results that indicate that during the freezing of aqueous solutions, freeze-induced phase separation (FIPS) into pure ice and a freeze-concentrated solution (FCS) takes place. Our observations involve the use of an optical cryo-microscope (OC-M) to record images and movies. The results visually indicate for the first time that there are two freezing processes for (NH4)3H(SO4)2/H2O solutions: (i) contact freezing, as is the case for pure water drops, and (ii) the Wegener-Bergeron-Findeisen process, which is the growth of frozen drops (ice) at the expense of liquid ones. We also present OC-M images of frozen micrometer-scaled H2SO4/H2O drops that support our previous finding that freezing of these solutions generates mixed-phase particles, namely an ice core coated with a FCS. These results are relevant for atmospheric as well as for pharmaceutical sciences.

  8. Short communication: Effects of vacuum freeze-drying on inactivation of Cronobacter sakazakii ATCC29544 in liquid media with different initial inoculum levels.

    Science.gov (United States)

    Jiao, Rui; Gao, Jina; Zhang, Xiyan; Zhang, Maofeng; Chen, Jiren; Wu, Qingping; Zhang, Jumei; Ye, Yingwang

    2017-03-01

    Vacuum freeze-drying is an important food-processing technology for valid retention of nutrients and bioactive compounds. Cronobacter sakazakii has been reported to be associated with severe infections in neonates through consumption of contaminated powdered infant formula. In this study, effects of vacuum freeze-drying treatment for 12, 24, and 36 h on inactivation of C. sakazakii with different initial inoculum levels in sterile water, tryptic soy broth (TSB), skim milk, and whole milk were determined. Results indicated that the lethality rate of C. sakazakii in each sample increased with the extension of vacuum freeze-drying time. With initial inoculum levels of 10(2) and 10(3) cfu/mL, the survival of C. sakazakii in different liquid media was significantly affected by vacuum freeze-drying for 12, 24, and 36 h. In addition, the lethality rates of C. sakazakii in whole milk, skim milk, and TSB was significantly reduced compared with those in sterile water. Furthermore, whole milk showed the strongest protective role for C. sakazakii cells, followed by skim milk and TSB medium. Using the scanning electron microscope, the intracellular damage and obvious distortion of C. sakazakii cells were observed after vacuum freeze-drying for 24 and 36 h compared with the untreated sample, and the injured cells increased with the extension of vacuum-drying time. We concluded that inactivation of vacuum freeze-drying on C. sakazakii cells is related to the food matrix, and a combination with other methods for inactivating C. sakazakii is required for ensuring microbial safety of powdered infant formula. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  9. Effect of acid whey and freeze-dried cranberries on lipid oxidation and fatty acid composition of nitrite-/nitrate-free fermented sausage made from deer meat

    Science.gov (United States)

    Karwowska, Małgorzata; Dolatowski, Zbigniew J.

    2017-01-01

    Objective This study evaluated the effect of acid whey and freeze-dried cranberries on the physicochemical characteristics, lipid oxidation and fatty acid composition of nitrite-free fermented sausage made from deer meat and pork fat. Antioxidant interactions between acid whey and cranberry compounds were also explored. Methods Four formulations of fermented venison sausage were prepared: F1 (control), F2 (with 5% liquid acid whey), F3 (with 0.06% of freeze-dried cranberries), and F4 (with 5% liquid acid whey and 0.06% of freeze-dried cranberries). Each sample was analyzed for pH, water activity (aw), heme iron content, 2-thiobarbituric acid reactive substances (TBARS) value and conjugated dienes at the end of the manufacturing process and at 30 and 90 days of refrigerated storage. Fatty acid composition was measured once at the end of the manufacturing process. Results At the end of ripening, all samples presented statistically different values for a pH range of 4.47 to pH 4.59. The sum of the unsaturated fatty acids was higher, while the conjugated diene and the TBARS values were lower in sausages with freeze-dried cranberries as compared to the control sausage. The highest content of heme iron (21.52 mg/kg) at day 90 was found in the sausage formulation with the addition of freeze-dried cranberries, which suggests that the addition of cranberries stabilized the porphyrin ring of the heme molecule during storage and thereby reduced the release of iron. The use of liquid acid whey in combination with cranberries appears to not be justified in view of the oxidative stability of the obtained products. Conclusion The results suggest that the application of freeze-dried cranberries can lower the intensity of oxidative changes during the storage of nitrite-free fermented sausage made from deer meat. PMID:27165018

  10. Effect of acid whey and freeze-dried cranberries on lipid oxidation and fatty acid composition of nitrite-/nitrate-free fermented sausage made from deer meat

    Directory of Open Access Journals (Sweden)

    Małgorzata Karwowska

    2017-01-01

    Full Text Available Objective This study evaluated the effect of acid whey and freeze-dried cranberries on the physicochemical characteristics, lipid oxidation and fatty acid composition of nitrite-free fermented sausage made from deer meat and pork fat. Antioxidant interactions between acid whey and cranberry compounds were also explored. Methods Four formulations of fermented venison sausage were prepared: F1 (control, F2 (with 5% liquid acid whey, F3 (with 0.06% of freeze-dried cranberries, and F4 (with 5% liquid acid whey and 0.06% of freeze-dried cranberries. Each sample was analyzed for pH, water activity (aw, heme iron content, 2-thiobarbituric acid reactive substances (TBARS value and conjugated dienes at the end of the manufacturing process and at 30 and 90 days of refrigerated storage. Fatty acid composition was measured once at the end of the manufacturing process. Results At the end of ripening, all samples presented statistically different values for a pH range of 4.47 to pH 4.59. The sum of the unsaturated fatty acids was higher, while the conjugated diene and the TBARS values were lower in sausages with freeze-dried cranberries as compared to the control sausage. The highest content of heme iron (21.52 mg/kg at day 90 was found in the sausage formulation with the addition of freeze-dried cranberries, which suggests that the addition of cranberries stabilized the porphyrin ring of the heme molecule during storage and thereby reduced the release of iron. The use of liquid acid whey in combination with cranberries appears to not be justified in view of the oxidative stability of the obtained products. Conclusion The results suggest that the application of freeze-dried cranberries can lower the intensity of oxidative changes during the storage of nitrite-free fermented sausage made from deer meat.

  11. Comparative study of two drying techniques used in radioactive source preparation: freeze-drying and evaporation using hot dry nitrogen jets.

    Science.gov (United States)

    Branger, T; Bobin, C; Iroulart, M-G; Lépy, M-C; Le Garrères, I; Morelli, S; Lacour, D; Plagnard, J

    2008-01-01

    Quantitative solid sources are used widely in the field of radionuclide metrology. With the aim to improve the detection efficiency for electrons and x-rays, a comparative study between two source drying techniques has been undertaken at LNE-Laboratoire National Henri Becquerel (LNE-LNHB, France). In this paper, freeze-drying using commercial equipment is compared with a system of drying using hot jets of nitrogen developed at Institute for Reference Materials and Measurements (IRMM, Belgium). In order to characterize the influence of self-absorption, the detection efficiencies for (51)Cr sources have been measured by coincidence counting and photon spectrometry.

  12. Characterization of freeze-dried egg melange long stored after irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bakalivanov, Stefan; Tsvetkova, Eli; Bakalivanova, Todorka; Tsvetkov, Tsvetan [Institute of Cryobiology and Food Technologies, 53 bd. Cherni vrah, 1407 Sofia (Bulgaria); Kaloyanov, Nikolay [University of Chemical Technology and Metallurgy, 8, bd. Kliment Ohridski, 1756 Sofia (Bulgaria)], E-mail: nikolaykaloyanov@yahoo.com; Grigorova, Stoyanka; Alexieva, Vanja [Institute of Cryobiology and Food Technologies, 53 bd. Cherni vrah, 1407 Sofia (Bulgaria)

    2008-01-15

    During the 4-year period of storage at room temperature of the freeze-dried (control group) and the freeze-dried and gamma-irradiated (2.0 and 3.5 kGy) whole hen's egg melange, no significant changes were found into the sensory and functional characteristics till the 28th month. The change in the number of SH groups was not unidirectional up to the 28th month and then it started to decrease in all investigated samples. During the entire period of investigation the amount of malondialdehyde in all three groups of egg melange was considerably below the allowed limit for foodstuffs. The most significant fractions of the protein spectra showed a general tendency of decrease during the storage.

  13. Spray freeze-dried nanofibrillated cellulose aerogels with thermal superinsulating properties.

    Science.gov (United States)

    Jiménez-Saelices, Clara; Seantier, Bastien; Cathala, Bernard; Grohens, Yves

    2017-02-10

    Nanofibrillated cellulose (NFC) aerogels were prepared by spray freeze-drying (SFD). Their structural, mechanical and thermal insulation properties were compared to those of NFC aerogels prepared by conventional freeze-drying (CFD). The purpose of this investigation is to develop superinsulating bioaerogels by reducing their pore size. Severe reduction of the aerogel pore size and skeleton architecture were observed by SEM, aerogels prepared by SFD method show a fibril skeleton morphology, which defines a mesoporous structure. BET analyses confirm the appearance of a new organization structure with pores of nanometric sizes. As a consequence, the thermal insulation properties were significantly improved for SFD materials compared to CFD aerogel, reaching values of thermal conductivity as low as 0.018W/(mK). Moreover, NFC aerogels have a thermal conductivity below that of air in ambient conditions, making them one of the best cellulose based thermal superinsulating material. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Optimizing the Chemical Compositions of Protective Agents for Freeze-drying Bifidobacterium longum BIOMA 5920

    Institute of Scientific and Technical Information of China (English)

    杨婵媛; 朱晓丽; 范代娣; 米钰; 骆艳娥; 惠俊峰; 苏然

    2012-01-01

    Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents to seek for maximum viability of Bifidobacterium longum BIOMA 5920 during freeze-drying. Through the compara- tive analysis of single protectant, the complex protective agents show better effect on the Bifidobacterium viability. Human-like collagen (HLC), trehalose and glycerol are confirmed as significant factors by Box-Behnken Design. The optimized formula for these three variables is tested as follows: HLC 1.23%, trehalose 11.50% and glycerol 4.65%. Under this formula, the viability is 88.23%, 39.67% higher in comparison to the control. The viable count is 1.07×10 9 cfu·g-1 , greatly exceeding the minimum viable count requirement (10 6 cfu·g-1 ).

  15. Preparation of redispersible liposomal dry powder using an ultrasonic spray freeze-drying technique for transdermal delivery of human epithelial growth factor.

    Science.gov (United States)

    Yin, Fei; Guo, Shiyan; Gan, Yong; Zhang, Xinxin

    2014-01-01

    In this work, an ultrasonic spray freeze-drying (USFD) technique was used to prepare a stable liposomal dry powder for transdermal delivery of recombinant human epithelial growth factor (rhEGF). Morphology, particle size, entrapment efficiency, in vitro release, and skin permeability were systematically compared between rhEGF liposomal dry powder prepared using USFD and that prepared using a conventional lyophilization process. Porous and spherical particles with high specific area were produced under USFD conditions. USFD effectively avoided formation of ice crystals, disruption of the bilayer structure, and drug leakage during the liposome drying process, and maintained the stability of the rhEGF liposomal formulation during storage. The reconstituted rhEGF liposomes prepared from USFD powder did not show significant changes in morphology, particle size, entrapment efficiency, or in vitro release characteristics compared with those of rhEGF liposomes before drying. Moreover, the rhEGF liposomal powder prepared with USFD exhibited excellent enhanced penetration in ex vivo mouse skin compared with that for powder prepared via conventional lyophilization. The results suggest that ultrasonic USFD is a promising technique for the production of stable protein-loaded liposomal dry powder for application to the skin.

  16. Selection of protectants for freezing and freeze-drying of acetic acid bacteria%醋酸菌冷冻、冷干保护剂的选择

    Institute of Scientific and Technical Information of China (English)

    王娜; 国石磊; 张永祥; 彭利沙; 李军

    2015-01-01

    In order to increase their freezing survival rate and freeze-drying survival rate,the effect of different protectants on the survival of Acetobacter aceti and Acetobacter pasteurianus ssp.pasteurianus during different processes including freezing and freeze-drying were studied herein.The protection effects of the different protectants on freezing and freeze-drying were also estimated.The results showed that the freezing survival rate of Acetobacter aceti was as follows:trehalose(73.58%) > corn dextrin(62.26%) > skim milk powder(60.38%),which were significantly higher than that of the control group (24.53%).The freezing survival rate of Acetobacter pasteurianus ssp.pasteurianus was as follows:dextran (95.35%) > skim milk powder (89.53%) > corn dextrin (88.37%) > trehalose (52.32%),which were significantly higher than that of the control group (2.23%).The freeze-drying survival rate of Acetobacter aceti was as follows:skim milk powder(92.86%) > lactose(81.25%) > glucose(46.88%),which were significantly higher than that of the control group (22.25%).The freeze-drying survival rate of Acetobacter pasteurianus ssp.pasteurianus was as follows:skim milk powde(72.92%) > trehalose(31.25%),which were significantly higher than that of the control group (12.08%).The other protectants showed varying degrees of protection effect on the strains.Trehalose and skim milk powder were prior selection for the protections of Acetobacter.%为提高醋酸菌在冷冻及冷干过程中的存活率,考察了10种不同保护剂分别对醋化醋杆菌和巴氏醋杆菌巴士亚种存活率的影响,评价了10种不同保护剂对醋酸菌的冷冻及冷干保护作用.结果发现,醋化醋杆菌的冷冻存活率:海藻糖(73.58%)>玉米糊精(62.26%)>脱脂乳粉(60.38%),明显高于对照的24.53% (P<0.05);巴氏醋杆菌巴士亚种的冷冻存活率:葡聚糖(95.35%)>脱脂乳粉(89.53%)>玉米糊精(88.37

  17. Fuzzy Logic-based expert system for evaluating cake quality of freeze-dried formulations.

    Science.gov (United States)

    Trnka, Hjalte; Wu, Jian X; Van De Weert, Marco; Grohganz, Holger; Rantanen, Jukka

    2013-12-01

    Freeze-drying of peptide and protein-based pharmaceuticals is an increasingly important field of research. The diverse nature of these compounds, limited understanding of excipient functionality, and difficult-to-analyze quality attributes together with the increasing importance of the biosimilarity concept complicate the development phase of safe and cost-effective drug products. To streamline the development phase and to make high-throughput formulation screening possible, efficient solutions for analyzing critical quality attributes such as cake quality with minimal material consumption are needed. The aim of this study was to develop a fuzzy logic system based on image analysis (IA) for analyzing cake quality. Freeze-dried samples with different visual quality attributes were prepared in well plates. Imaging solutions together with image analytical routines were developed for extracting critical visual features such as the degree of cake collapse, glassiness, and color uniformity. On the basis of the IA outputs, a fuzzy logic system for analysis of these freeze-dried cakes was constructed. After this development phase, the system was tested with a new screening well plate. The developed fuzzy logic-based system was found to give comparable quality scores with visual evaluation, making high-throughput classification of cake quality possible. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

  18. Sugars as bulking agents to prevent nano-crystal aggregation during spray or freeze-drying.

    Science.gov (United States)

    Kumar, Sumit; Gokhale, Rajeev; Burgess, Diane J

    2014-08-25

    In this study, the effect of low and high molecular weight sugars on indomethacin nano-crystalline suspension powders prepared by spray or freeze-drying was evaluated. Dowfax 2A1 (negatively charged surfactant) was utilized as indomethacin nanosuspensions stabilizer. Dried crystalline powders with or without sugars were characterized for crystallinity, particle size and powder yield. Interactions between the nanosuspension stabilizer (i.e. Dowfax 2A1) and sugars were investigated by utilizing IR spectroscopy and contact angle measurements. The nanosuspension formulations containing small molecular weight sugars were non-aggregating compared to those containing polysaccharides. Additionally, higher powder yields were observed with formulations containing sugars with higher glass transition temperature during spray drying. The formulations containing low glass transition temperature sugars were sticking to the spray drier glass walls and thus resulted in lower yields. The small molecular weight sugars showed favorable interactions with Dowfax 2A1, as evident by the IR and contact angle data, possibly resulting in minimal nano-crystal aggregation during spray or freeze-drying. A combination of sugars (i.e. small molecular weight and polysaccharides) may be utilized to achieve higher spray-drying yields and non-aggregating nano-crystalline powders.

  19. Effects of Drying Processes on the Antioxidant Properties in Sweet Potatoes

    Institute of Scientific and Technical Information of China (English)

    YANG Jing; CHEN Jin-feng; ZHAO Yu-ying; MAO Lin-chun

    2010-01-01

    The effects of different drying methods (hot-air drying, microwave drying and vacuum-freeze drying) on the antioxidant activity and antioxidants in sweet potato (Ipomoea batatas L. Lam.) tubers were investigated to determine the potential drying process. Sweet potato tubers were cut into 5 mm thick slices, steamed at 100~C for 10 rain, then dried in either hot-air, microwave, or vacuum-freeze. The dried sweet potatoes in microwave possessed the highest antioxidant activity,while the lowest activity was observed in hot-air dried samples. The phenolic contents were positively correlated with scavenging activity and reducing power of DPPH+. The microwave drying retains the highest antioxidant activity with the highest content of phenolic compounds in dried sweet potatoes. β-carotene and ascorbic acid showed minor contribution to the antioxidant activity in dried sweet potatoes.

  20. Atmospheric freeze drying for the reduction of powder electrostatics of amorphous, low density, high surface area pharmaceutical powders.

    Science.gov (United States)

    O'Donnell, K P; Cai, Z; Schmerler, P; Williams, R O

    2013-02-01

    Amorphous itraconazole (ITZ) was prepared by Thin Film Freezing (TFF) utilizing 1,4-dioxane as the solvent with subsequent solvent removal via conventional tray lyophilization (ITZ LYO) or atmospheric freeze drying (ITZ AFD). ITZ AFD was prepared under various drying conditions to assess the influence of drying parameters on powder properties. XRD analysis confirmed all products were amorphous and DSC analysis revealed both drying processes resulted in the formation of the nematic mesophase of ITZ. SEM revealed a larger pore size and agglomerate size with fewer fine particles (i.e. less than 10 microns in diameter) for ITZ AFD compared to ITZ LYO. Residual solvent analysis revealed a primary drying temperature of -10°C resulted in residual solvent levels above the acceptable limits set by the International Conference on Harmonization as a result of microcollapse. Primary drying temperatures of less than -10°C resulted in acceptable residual solvent levels. The extent of microcollapse did not alter the macrostructure of the resulting powder. Powder flowability was determined to be similar for ITZ AFD and ITZ LYO based on Carr's index and the Hausner ratio, as well as by dynamic angle of repose. All powders displayed poor flowability. Chargeability measurements demonstrated a lower charge transfer for ITZ AFD powders compared to ITZ LYO due to a combination of factors including differences in residual solvent level, particle size, pore size, surface area, and fine particles content. The reduction in chargeability as a result of AFD is highly desirable because it allows for improved powder handling and use post-production.

  1. Study on the Efficiency of the Vegetables Freezing Process

    Directory of Open Access Journals (Sweden)

    Simona Paulikienė

    2014-10-01

    Full Text Available Changes taking place during the storage of the products of vegetable origin are inevitable. Products can deteriorate and change their shelf appearance, nutritional value, texture, taste and aroma. Freezing is one of the most appropriate technological operations for the product storage. By freezing products of vegetable origin, cleaner production technology can be used to consume less energy and to preserve quality of the product as well as valuable nutritional/ biologically active substances.The study of vegetable freezing process was carried out by freezing red beets. Beetroot was frozen in a chamber with controlled climatic environment - the Feutron.A portion of moisture content always evaporates from products of vegetable origin at freezing. Air flow velocity has a great influence on freezing rate of vegetables. Intensity of moisture evaporation also increases up to the moment of freezing-up of the surface layers.Intensity of retardation of the evaporation process depends on a peel and on stomata on it. Moisture evaporation’s retardation rate of the red beet peel εevp.ap = 0,50 ± 0,02. When air velocity was 0,15 m/s - εevp varied from 0,47 to 0,53, whilst at the air flow velocity 0,65 m/s - εevp = 0,37 – 0,45.Purpose of the study - to analyse the freezing process of vegetables (by the red beetroot example under the influence of different environment factors.DOI: http://dx.doi.org/10.5755/j01.erem.69.3.6064

  2. NaCl stress impact on the key enzymes in glycolysis from Lactobacillus bulgaricus during freeze-drying.

    Science.gov (United States)

    Li, Chun; Sun, Jinwei; Qi, Xiaoxi; Liu, Libo

    2015-01-01

    The viability of Lactobacillus bulgaricus in freeze-drying is of significant commercial interest to dairy industries. In the study, L.bulgaricus demonstrated a significantly improved (p enzymes in glycolysis during 2% NaCl stress were studied. NaCl stress significantly enhanced (p enzymes (phosphofructokinase, pyruvate kinase, and lactate dehydrogenase) decreased during freeze-drying, and NaCl stress were found to improve activities of these enzymes before and after freeze-drying. However, a transcriptional analysis of the corresponding genes suggested that the effect of NaCl stress on the expression of the pfk2 gene was not obvious. The increased survival of freeze-dried cells of L. bulgaricus under NaCl stress might be due to changes in only the activity or translation level of these enzymes in different environmental conditions but have no relation to their mRNA transcription level.

  3. Tertiary combination of freeze-dried urine of Indian breeds of cow with plant products against snail Lymnaea acuminata

    National Research Council Canada - National Science Library

    Kumar, Shiv; Singh, D K; Singh, Vinay Kumar

    2012-01-01

    .... In the present study molluscicidal activity of tertiary combination of freeze-dried urine of different Indian breeds of cow Sahiwal, Geer and Tharparkar with Annona squamosa seed powder, Ferula...

  4. Effectiveness of Adjuncts with Demineralized Freeze Dried Bone Allograft in Treatment of Intrabony Defects - A systematic review

    National Research Council Canada - National Science Library

    GB Parthasarathy; ND Jayakumar; M Sankari; SS Varghese; G Karthikayan; S Panda

    2015-01-01

      Abstract Objective: To systematically evaluate the effect of adjuncts with demineralized freeze dried bone in the treatment of intrabony defects in terms of clinical and radiological outcomes. Methods...

  5. Freeze-drying of HESylated IFNα-2b: Effect of HESylation on storage stability in comparison to PEGylation.

    Science.gov (United States)

    Liebner, Robert; Bergmann, Sarah; Hey, Thomas; Winter, Gerhard; Besheer, Ahmed

    2015-11-10

    A comparison of lyophilized PEGylated and HESylated IFNα was carried out to investigate the influence of protein conjugation, lyoprotectants as well as storage temperature on protein stability. Results show that PEG tends to crystallize during freeze-drying, reducing protein stability upon storage. In contrast, HESylation(®) drastically improved the stability over PEGylation by remaining totally amorphous during lyophilization, with and without lyoprotectants while providing a high glass transition temperature of the freeze-dried cakes.

  6. A comparative evaluation of freeze dried bone allograft and decalcified freeze dried bone allograft in the treatment of intrabony defects: A clinical and radiographic study

    Directory of Open Access Journals (Sweden)

    Rajat Gothi

    2015-01-01

    Full Text Available Background: Ideal graft material for regenerative procedures is autogenous bone graft but the major disadvantage with this graft is the need for a secondary surgical site to procure donor material and the frequent lack of intraoral donor site to obtain sufficient quantities of autogenous bone for multiple or deep osseous defects. Hence, to overcome these disadvantages, bone allografts were developed as an alternative source of graft material. Materials and Methods: In 10 patients with chronic periodontitis, 20 bilateral infrabony defects were treated with freeze dried bone allograft (FDBA-Group A and decalcified freeze dried bone allograft (DFDBA-Group B. Clinical and radiographic parameters were assessed preoperatively and at 3 months and 6 months postoperatively. Data thus obtained was subjected to statistical analysis. Results: Significant improvement in the reduction in probing depth and relative attachment level (RAL from the baseline to 3 months to baseline to 6 months in group A and group B, which was statistically significant but no statistically significant reduction was seen between 3 months and 6 months. On inter-group comparison, no significant differences were observed at all-time points. In adjunct to the probing depth and RAL, the radiographic area of the defect showed a similar trend in intra-group comparison and no significant difference was seen on inter-group comparison at all-time points. Conclusions: Within the limitations of the current study, it can be concluded that DFDBA did not show any improvement in the clinical and radiographic parameters in the treatment of the intrabony defects as compared to FDBA.

  7. Freeze-dried bone allografts sterilized with gamma radiation and the clinical use in harelip

    Energy Technology Data Exchange (ETDEWEB)

    Luna Z, D.; Reyes F, M. L. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Diaz M, I.; Cruz A, L. C. [Centro Estatal de Trasplantes del Estado de Mexico, Pablo Sidar No. 602, Col. Universidad, Toluca 50130, Estado de Mexico (Mexico); Vazquez R, M. A., E-mail: daniel.luna@inin.gob.m [Centro de Especialidades Odontologicas, Instituto Materno Infantil del Estado de Mexico, Paseo Colon esquina Felipe Angeles s/n, Col. Villa Hogar, Toluca 50170, Estado de Mexico (Mexico)

    2010-10-15

    Bone for transplant is part of the musculoskeletal tissue join with fascia lat, tendon, ligament and cartilage. Bone is formed by cells (osteocytes, osteoblasts and osteoclasts) and extracellular matrix formed mainly by collagen and hydroxyapatite, which gives strength and elasticity to the bone. The bone function in the body is to move, support, organs protection, production of blood cells and store minerals. The musculoskeletal tissue is processed in specialized tissue banks using gamma radiation of cobalt-60 for sterilization at 25 kGy doses at very low temperature or at room temperature, getting tissues with high quality for clinical applications in injured patients. The process of the bone for transplants varies depend on the size and the surgeon likes, nevertheless in general the large ones are preserved at low temperature (-80 C), meanwhile the short ones are freeze-dried preserved. The musculoskeletal diseases represent the most common physical incapacity, which affect million of people around the world. Due to the human body has 206 bones, during a bone injury each bone can be replaced or repaired with several devices, in general the surgeon goes to a specialized tissue banks, to get the bone, due to the high bone quantity on the body and the number of bone injuries and diseases, the bone is the most transplanted around the world only behind the blood. The bone can be processed in several sizes and shapes, one of these is bone powder from allograft, which is used over all for bone filling, this can be take advantage for cleft lip and palate defects, which is a birth defect, this can affect the way the child's face looks, it can also lead to problems with eating, talking and ear infections. The description of the bone powder process is presented and the clinical use of this powder in several pediatric patients for cleft lip and palate defects is described. (Author)

  8. A sustainable freeze-drying route to porous polysaccharides with tailored hierarchical meso- and macroporosity.

    Science.gov (United States)

    Borisova, Aleksandra; De Bruyn, Mario; Budarin, Vitaliy L; Shuttleworth, Peter S; Dodson, Jennifer R; Segatto, Mateus L; Clark, James H

    2015-04-01

    Bio-derived polysaccharide aerogels are of interest for a broad range of applications. To date, these aerogels have been obtained through the time- and solvent-intensive procedure of hydrogel fomation, solvent exchange, and scCO2 drying, which offers little control over meso/macropore distribution. A simpler and more versatile route is developed, using freeze drying to produce highly mesoporous polysaccharide aerogels with various degrees of macroporosity. The hierarchical pore distribution is controlled by addition of different quantities of t-butanol (TBA) to hydrogels before drying. Through a systematic study an interesting relationship between the mesoporosity and t-butanol/water phase diagram is found, linking mesoporosity maxima with eutectic points for all polysaccharides studied (pectin, starch, and alginic acid). Moreover, direct gelation of polysaccharides in aqueous TBA offers additional time savings and the potential for solvent reuse. This finding is a doorway to more accessible polysaccharide aerogels for research and industrial scale production, due to the widespread accessibility of the freeze drying technology and the simplicity of the method.

  9. Study on Freeze-drying of Water Chestnut%马蹄真空冷冻干燥实验的研究

    Institute of Scientific and Technical Information of China (English)

    陈学玲; 何建军; 关健; 梅新; 程薇; 熊光权; 叶丽秀; 陈玉霞

    2011-01-01

    利用真空冷冻干燥技术对马蹄进行保鲜加工研究.利用电阻法测量了马蹄的共晶点和共熔点,采用L12(35)正交试验方法,研究了影响冻干产品质量和设备生产能力的主要参数,评定了冻干产品的含水量、外观、复水性等特性.实验结果表明,马蹄冻干的最佳工艺为:速冻温度-36℃,速冻时间20h,干燥升华时仓压(120±10)Pa;干燥解析时仓压(40±10)Pa,解析时的搁板温度50℃,干燥时间14h.%Water Chestnut were stored and processed by Freeze-drying.Eutectic point and consolute point were measured by resistivity method.The main factors affecting the properties of freeze-drying product and production capacity of the equipment were studied using L12(35) orthogonal experiments.Water content of product,product form,rehydration character were evaluated.The optimal technics for freeze-drying Water Chestnut were following:deep freeze temperature-36℃,deep freeze time 20h,pressure of drying room while vacuum sublimation drying(120±10)Pa,pressure of drying room while vaccum resolution drying(40±10)Pa,shelf temperature while vacuum resolution drying 50℃,drying time 14h.

  10. Stability evaluation of freeze-dried Lactobacillus paracasei subsp. tolerance and Lactobacillus delbrueckii subsp. bulgaricus in oral capsules.

    Science.gov (United States)

    Jalali, M; Abedi, D; Varshosaz, J; Najjarzadeh, M; Mirlohi, M; Tavakoli, N

    2012-01-01

    Freeze-drying is a common preservation technology in the pharmaceutical industry. Various studies have investigated the effect of different cryoprotectants on probiotics during freeze-drying. However, information on the effect of cryoprotectants on the stability of some Lactobacillus strains during freeze-drying seems scarce. Therefore, the aim of the present study was to establish production methods for preparation of oral capsule probiotics containing Lactobacillus paracasei subsp. tolerance and Lactobacillus delbrueckii subsp. Bulgaricus. It was also of interest to examine the effect of various formulations of cryoprotectant media containing skim milk, trehalose and sodium ascorbate on the survival rate of probiotic bacteria during freeze-drying at various storage temperatures. Without any cryoprotectant, few numbers of microorganisms survived. However, microorganisms tested maintained higher viability after freeze-drying in media containing at least one of the cryoprotectants. Use of skim milk in water resulted in an increased viability after lyophilization. Media with a combination of trehalose and skim milk maintained a higher percentage of live microorganisms, up to 82%. In general, bacteria retained a higher number of viable cells in capsules containing freeze-dried bacteria with sodium ascorbate after three months of storage. After this period, a marked decline was observed in all samples stored at 23°C compared to those stored at 4°C. The maximum survival rate (about 72-76%) was observed with media containing 6% skim milk, 8% trehalose and 4% sodium ascorbate.

  11. Optimization of a protective medium for freeze-dried Pichia membranifaciens and application of this biocontrol agent on citrus fruit.

    Science.gov (United States)

    Niu, X; Deng, L; Zhou, Y; Wang, W; Yao, S; Zeng, K

    2016-07-01

    To optimize a protective medium for freeze-dried Pichia membranifaciens and to evaluate biocontrol efficacies of agents against blue and green mould and anthracnose in citrus fruit. Based on the screening assays of saccharides and antioxidants, response surface methodology was used to optimize sucrose, sodium glutamate and skim milk to improve viability of freeze-dried Pi. membranifaciens. Biocontrol assays were conducted between fresh and freeze-dried Pi. membranifaciens against Penicillium italicum, Penicillium digitatum and Colletotrichum gloeosporioides in citrus fruit. Solving the regression equation indicated that the optimal protective medium was 6·06% (w/v) sucrose combined with 3·40% (w/v) sodium glutamate and 5·43% (w/v) skim milk. Pi. membranifaciens freeze-dried in the optimal protective medium showed 76·80% viability, and retained biocontrol efficacy against Pe. italicum, Pe. digitatum and Co. gloeosporioides in citrus fruit. The optimal protective medium showed more effective protective properties than each of the three protectants used alone. The viability of freeze-dried Pi. membranifaciens finally reached 76·80%. Meanwhile, the biocontrol efficacies showed no significant difference between fresh and freeze-dried yeast against Pe. italicum, Pe. digitatum and Co. gloeosporioides in citrus fruit. The results showed the potential value of Pi. membranifaciens CICC 32259 for commercialization. © 2016 The Society for Applied Microbiology.

  12. Synthesis of high-performance Li2FeSiO4/C composite powder by spray-freezing/freeze-drying a solution with two carbon sources

    Science.gov (United States)

    Fujita, Yukiko; Iwase, Hiroaki; Shida, Kenji; Liao, Jinsun; Fukui, Takehisa; Matsuda, Motohide

    2017-09-01

    Li2FeSiO4 is a promising cathode active material for lithium-ion batteries due to its high theoretical capacity. Spray-freezing/freeze-drying, a practical process reported for the synthesis of various ceramic powders, is applied to the synthesis of Li2FeSiO4/C composite powders and high-performance Li2FeSiO4/C composite powders are successfully synthesized by using starting solutions containing both Indian ink and glucose as carbon sources followed by heating. The synthesized composite powders have a unique structure, composed of Li2FeSiO4 nanoparticles coated with a thin carbon layer formed by the carbonization of glucose and carbon nanoparticles from Indian ink. The carbon layer enhances the electrochemical reactivity of the Li2FeSiO4, and the carbon nanoparticles play a role in the formation of electron-conducting paths in the cathode. The composite powders deliver an initial discharge capacity of 195 and 137 mAh g-1 at 0.1 C and 1 C, respectively, without further addition of conductive additive. The discharge capacity at 1 C is 72 mAh g-1 after the 100th cycle, corresponding to approximately 75% of the capacity at the 2nd cycle.

  13. Experimental determination of the key heat transfer mechanisms in pharmaceutical freeze-drying.

    Science.gov (United States)

    Ganguly, Arnab; Nail, Steven L; Alexeenko, Alina

    2013-05-01

    The study is aimed at quantifying the relative contribution of key heat transfer modes in lyophilization. Measurements of vial heat transfer rates in a laboratory-scale freeze-dryer were performed using pure water, which was partially sublimed under various conditions. The separation distance between the shelf and the vial was systematically varied, and sublimation rates were determined gravimetrically. The heat transfer rates were observed to be independent of separation distance between the vial and the shelf and linearly dependent on pressure in the free molecular flow limit, realized at low pressures (120 mTorr), heat transfer rates were independent of pressure and inversely proportional to separation distance. Previous heat transfer studies in conventional freeze-drying cycles have attributed a dominant portion of the total heat transfer to radiation, the rest to conduction, whereas convection has been found to be insignificant. Although the measurements reported here confirm the significance of the radiative and gas conduction components, the convective component has been found to be comparable to the gas conduction contribution at pressures greater than 100 mTorr. The current investigation supports the conclusion that the convective component of the heat transfer cannot be ignored in typical laboratory-scale freeze-drying conditions. Copyright © 2013 Wiley Periodicals, Inc.

  14. Ketahanan dan viabilitas probiotik bakteri asam laktat selama proses pembuatan kultur kering dengan metode freeze dan spray drying [Survival and Viability of Lactid Acid Bacteria Probiotic during production of Dried Culture Using Freeze and Spray Drying Methods

    Directory of Open Access Journals (Sweden)

    Erni Harmayani 1

    2001-08-01

    Full Text Available Selection on 36 lactid aid bacteria isolate from various source (dadih, sausage, infant faces, gato, chinese leaf pickle, growol and yoghurt has been carried out based on their potency to reduce choresterol. Based on their ability to assimilate choresterol, conjugate bile solt, restency on bile salt and low pH, three isolates i.e. Lactobacillus sp. Dad 13, L. asidophillus D2 and L. plantarum Mut 7 have been chosen for further study. Viability of selected cultures during biomass production using coconut water with addition of 0.5% yeast extract, and during production of dried starter culture using freeze and spray dried were investigated. The results show that the growth patern of the three isolates selected were almost similar i.e. reaching maximum amount after 16 hours fermentation at 37°C. biomass production using coconut water produced 109 cfu/ml after 16-18 hours incubation at 37°C. decrease on viability after drying using freeze drier ranged between 0.5-2 log cycles, while that of storage of freeze dried culture during 4 weeks at -20°C caused descreasing in viability of 26-56%.

  15. A freeze-dried graphene counter electrode enhances the performance of dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Kai-Hsiang; Wang, Hong-Wen, E-mail: hongwen@cycu.edu.tw

    2014-01-01

    A flexible graphene/polyimide (PI) counter electrode without a fluorine-doped tin oxide (FTO) layer has been fabricated for dye-sensitized solar cell (DSSCs) applications. The flexible counter electrode consists of polyimide double-sided tape as a substrate beneath a graphene film acting as the conductive and catalytic layer. Chemically reduced graphene oxide (rGO) on the PI electrode (rGO-PI) shows comparable catalytic activity to that of the reference sputtered platinum/FTO counter electrodes (Sputter-Pt/FTO). A DSSC with a freeze-dried rGO-PI (FD-rGO-PI) counter electrode shows an overall conversion efficiency (η) of 5.45%, while that of the conventional Sputter-Pt/FTO electrode is 5.52%. The DSSC with a thermally dried rGO-PI (Gel-rGO-PI) counter electrode (not freeze-dried) exhibits a smooth morphology and much poorer performance (η = 1.61%). Field emission scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry measurements demonstrate that the FD-rGO-PI electrode possesses a porous structure, numerous edges, minimum charge-transfer resistance and a higher electrocatalytic activity toward the I{sub 3}{sup −}/I{sup −} redox couple than that of the Gel-rGO-PI electrode. The high electrocatalytic activity, facile preparation procedure, absence of FTO, and material flexibility render the FD-rGO-PI electrode an ideal alternative to conventional DSSC counter electrodes. - Highlights: • Highly rough and conductive graphene-based counter electrode is synthesized. • The characteristics of graphene surface by freeze drying are different. • The graphene counter electrode exhibits comparable performance to that of sputtered Pt one.

  16. Depositing nanoparticles on a silicon substrate using a freeze drying technique

    Science.gov (United States)

    Sigehuzi, Tomoo

    2017-08-01

    For the microscopic observation of nanoparticles, an adequate sample preparation is an essential part of this task. Much research has been performed for usable preparation methods that will yield aggregate-free samples. A freeze drying technique, which only requires a -80 °C freezer and a freeze dryer, is shown to provide an on-substrate dispersion of mostly isolated nanoparticles. The particle density could be made sufficiently high for efficient observations using atomic force microscopy. Since this sandwich method is purely physical, it could be applied to deposit various nanoparticles independent of their surface chemical properties. Suspension film thickness, or the dimensionality of the suspension film, was shown to be crucial for the isolation of the particles. Silica nanoparticles were dispersed on a silicon substrate using this method and the sample properties were examined using atomic force microscopy.

  17. Effect of freeze-drying, cryoprotectants and storage conditions on the stability of secondary structure of insulin-loaded solid lipid nanoparticles.

    Science.gov (United States)

    Soares, Sandra; Fonte, Pedro; Costa, Ana; Andrade, José; Seabra, Vítor; Ferreira, Domingos; Reis, Salette; Sarmento, Bruno

    2013-11-18

    This study aims to monitor the secondary structure behaviour of insulin when it is encapsulated into solid lipid nanoparticles (SLN), under the influence of several critical processing parameters. Insulin was used as a therapeutic protein model. Physicochemical properties of insulin-loaded SLN (Ins-SLN) were assessed, with special focus on the insulin secondary structure after its encapsulation into SLN and after freeze-drying using different cryoprotectants (glucose, fructose and sorbitol). Additionally, a 6-month stability study was performed to evaluate the maintenance of insulin secondary structure over time at different storage conditions (4 °C/60% RH, 25 °C/60% RH, 40 °C/75% RH). Ins-SLN were successfully produced with a mean and narrow particle size around 400 nm, zeta potential around -13 mV, an insulin association efficiency of 84%. Physical-chemical properties of SLN were maintained after freeze-drying. FTIR results showed that encapsulated insulin maintained a native-like structure in a degree of similarity around 92% after production, and 84% after freeze-drying. After 6 months, freeze-dried Ins-SLN without cryoprotectant stored at 40 °C/75% RH presented the same degree of structure preservation and morphology. Results revealed that insulin structure can be significantly protected by SLN matrix itself, without a cryoprotectant agent, even using a non-optimized freeze-drying process, and under the harsher storage conditions. Multivariable experimental settled the process parameters to fit with the desired product quality attributes regarding protein and nanoparticle stability.

  18. Evaluation of Freeze-Dried Kefir Coculture as Starter in Feta-Type Cheese Production

    Science.gov (United States)

    Kourkoutas, Y.; Kandylis, P.; Panas, P.; Dooley, J. S. G.; Nigam, P.; Koutinas, A. A.

    2006-01-01

    The use of freeze-dried kefir coculture as a starter in the production of feta-type cheese was investigated. Maturation of the produced cheese at 4°C was monitored for up to 70 days, and the effects of the starter culture, the salting method, and the ripening process on quality characteristics were studied. The use of kefir coculture as a starter led to increased lactic acid concentrations and decreased pH values in the final product associated with significantly higher conversion rates compared to salted rennet cheese. Determination of bacterial diversity at the end of the ripening process in salted kefir and rennet cheeses by denaturing gradient gel electrophoresis technology, based on both DNA and RNA analyses, suggested a potential species-specific inhibition of members of the genera Staphylococcus and Psychrobacter by kefir coculture. The main active microbial associations in salted kefir cheese appeared to be members of the genera Pseudomonas and Lactococcus, while in salted rennet cheese, Oxalobacteraceae, Janthinobacterium, Psychrobacter, and Pseudomonas species were noted. The effect of the starter culture on the production of aroma-related compounds responsible for cheese flavor was also studied by the solid-phase microextraction-gas chromatography-mass spectrometry technique. Kefir coculture also appeared to extend the shelf life of unsalted cheese. Spoilage of kefir cheese was observed on the 9th and 20th days of preservation at 10 and 5°C, respectively, while spoilage in the corresponding rennet cheese was detected on the 7th and 16th days. Microbial counts during preservation of both types of unsalted cheese increased steadily and reached similar levels, with the exception of staphylococci, which were significantly lower in unsalted kefir cheese. All types of cheese produced with kefir as a starter were approved and accepted by the panel during the preliminary sensory evaluation compared to commercial feta-type cheese. PMID:16957238

  19. Microencapsulation of saffron petal anthocyanins with cress seed gum compared with Arabic gum through freeze drying.

    Science.gov (United States)

    Jafari, Seid-Mahdi; Mahdavi-Khazaei, Katayoun; Hemmati-Kakhki, Abbas

    2016-04-20

    In this research, encapsulation efficiency of cress seed gum (CSG) as a native hydrocolloid was compared with Arabic gum (AG) and maltodextrin (dextrose equivalent of 20 (M20), and 7 (M7)) for saffron (Crocus sativus) petal's extract by freeze drying method. Combinations of CSG-M20, AG-M20, and M7-M20 with ratios of 50:50 and M20 alone (100%) were used as wall materials. A mixture of 1:5 (based on dry matter) between core (concentrated anthocyanin extract of saffron petal) and wall materials were freeze dried and stability of encapsulated anthocyanins along with color parameters (a*, b*, L*, C, H° and TCD) of final powders were measured during 10 weeks of storage (at 35°C as an accelerated method). Total anthocyanins were determined through pH differential method every week. Four prepared formulations of encapsulated powders didn't show any significant differences (P>0.01) in terms of total anthocyanin content measured immediately after production and after 10 weeks storage. AG-M20 mixture and M20 alone showed the highest and lowest TCD, respectively. The mixture of CSG-M20 in comparison with AG-M20 and M20 had the same protecting effect (P<0.01) but showed a relatively high TCD (9.33).

  20. Sol Freeze Dry Nd:YAG Nanopowder Synthesis and Sinterability Studies

    Directory of Open Access Journals (Sweden)

    Rekha Mann

    2015-09-01

    Full Text Available Citrate nitrate sol freeze dry synthesis of 2 atomic % neodymium ion doped Yttrium Aluminium Oxide (Nd:YAG nanopowders was explored for the first time. Sol was prepared by dissolving nitrates of Al3+, Y3+ and Nd3+ keeping molar ratio to be 5: 2.94: 0.06. Total metal ion to citric acid ratio was optimised at 1 is to 0.25. Sol was freeze dried at -80 °C for 48 h. Dried mass thus obtained was calcined at 1000 °C for 2 h to give phase pure Nd:YAG as characterised by FTIR and XRD. Particles were in the size range of 35 nm - 50 nm with close to spherical morphology as observed by TEM. Nanopowder was compacted and sintered at 1700 °C for 5 h under 10-6 mbar followed by hot isostatic press at 1750 °C for 4 h under 200 MPa, to give 71 per cent transmission at 1064 nm indicating synthesis of well sinterable Nd:YAG nanopowders.

  1. KINETICS OF THE PROCESS OF CONCENTRATION BY FREEZING THE CHERRY JUICE

    Directory of Open Access Journals (Sweden)

    S. T. Antipov

    2014-01-01

    Full Text Available Summary. The urgency of theme is substantiated and the basic directions of studies are determined. Is substantiated the mechanism of the process of the concentration of liquid media by freezing moisture, that is determined in essence by the conditions for the migration of the molecules of water to the frontal surface of crystallization and their incorporation into the crystal structure of ice. It is shown that the regime of freezing moisture is characterized by the temperature of the heat exchange surface, which receives heat of crystallization of moisture, by the speeds of displacement and with the surface area of the contact of the being transferred heat media, by form and by the concentration of the dissolved substances of product. The process of heat exchange between the surface of crystallization and the workable technological medium is described. The schematic of the work of the experimental freezing out installation and the procedure of experiences is represented. Are investigated a change in the average value of a quantity of frozen out ice from the unit of heat exchange surface, which freezes out installations in the time, reflected in the form of the curves of increase and rate of growth in the icy phase on the surface of the heat exchange elements of area of 0.08 m2 , in 3600 seconds depending on the temperature of the heat exchange surface and initial content of dry matter in the cherry juice. An increase in the initial content of dry matter in the cherry juice at constant temperature of boiling refrigerant in the vaporizer of the freezing out installation nonlinearly reduces the specific quantity of ice, which was being formed on the heat exchange surface. A change in the boiling point of refrigerant also causes a nonlinear increase in the specific quantity of ice, frozen out on the heat exchange surface. The obtained curves of the rate of growth in the icy phase make it possible to isolate the sections of the crystallization of the

  2. Large scale synthesis of nanostructured zirconia-based compounds from freeze-dried precursors

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, A.; Villanueva, R.; Vie, D.; Murcia-Mascaros, S.; Martinez, E.; Beltran, A. [Institut de Ciencia dels Materials, Parc Cientific, Universitat de Valencia, PO Box 22085, 46071 Valencia (Spain); Sapina, F., E-mail: fernando.sapina@uv.es [Institut de Ciencia dels Materials, Parc Cientific, Universitat de Valencia, PO Box 22085, 46071 Valencia (Spain); Vicent, M.; Sanchez, E. [Instituto de Tecnologia Ceramica-Asociacion de Investigacion de las Industrias Ceramicas, Universitat Jaume I, 12006 Castellon (Spain)

    2013-01-15

    Nanocrystalline zirconia powders have been obtained at the multigram scale by thermal decomposition of precursors resulting from the freeze-drying of aqueous acetic solutions. This technique has equally made possible to synthesize a variety of nanostructured yttria or scandia doped zirconia compositions. SEM images, as well as the analysis of the XRD patterns, show the nanoparticulated character of those solids obtained at low temperature, with typical particle size in the 10-15 nm range when prepared at 673 K. The presence of the monoclinic, the tetragonal or both phases depends on the temperature of the thermal treatment, the doping concentration and the nature of the dopant. In addition, Rietveld refinement of the XRD profiles of selected samples allows detecting the coexistence of the tetragonal and the cubic phases for high doping concentration and high thermal treatment temperatures. Raman experiments suggest the presence of both phases also at relatively low treatment temperatures. - Graphical abstract: Zr{sub 1-x}A{sub x}O{sub 2-x/2} (A=Y, Sc; 0{<=}x{<=}0.12) solid solutions have been prepared as nanostructured powders by thermal decomposition of precursors obtained by freeze-drying, and this synthetic procedure has been scaled up to the 100 g scale. Highlights: Black-Right-Pointing-Pointer Zr{sub 1-x}A{sub x}O{sub 2-x/2} (A=Y, Sc; 0{<=}x{<=}0.12) solid solutions have been prepared as nanostructured powders. Black-Right-Pointing-Pointer The synthetic method involves the thermal decomposition of precursors obtained by freeze-drying. Black-Right-Pointing-Pointer The temperature of the thermal treatment controls particle sizes. Black-Right-Pointing-Pointer The preparation procedure has been scaled up to the 100 g scale. Black-Right-Pointing-Pointer This method is appropriate for the large-scale industrial preparation of multimetallic systems.

  3. Dielectric properties of a BaTiO{sub 3} ceramic prepared by using the freeze drying method

    Energy Technology Data Exchange (ETDEWEB)

    Al-Shakarchi, Emad K. [Al-Nahrain University, Baghdad (Iraq)

    2010-08-15

    A modified catecholate process has been developed to synthesize high-purity barium titanate by using a freeze drying method to produce ultra-fine powders from a barium titanium catechol complex, Ba[Ti(C{sub 6}H{sub 4}O{sub 2}){sub 3}]. The complex prepared from TiCl{sub 4}, C{sub 6}H{sub 4}(OH){sub 2} and BaCO{sub 3}. The freeze drying of the complex Ba[Ti(C{sub 6}H{sub 4}O{sub 2}){sub 3}] under a primary vacuum at a freezing temperature of -50 .deg. C for a long time 24 hrs is necessary to transfer the complex Ba[Ti(C{sub 6}H{sub 4}O{sub 2}){sub 3}] from a liquid phase to a solid phase. A subsequent calcination of the complex for 12 hrs at a temperature of 700 .deg. C was very important to remove the acetates from the mixture. Finally, a sintering process was required for the pellets so that high density samples could be investigated. The dielectric properties, the structural phase, and the particle size of the sintered pellets have investigated as functions of frequency and temperature in order to determine the critical temperature for the phase transition. X-ray diffraction was used to investigate the structural properties and the particle size. The tetragonal phase of BaTiO{sub 3} with the lattice constants a = b = 3.9734 A, and c = 4.012 A was successfully obtained.

  4. Encapsulation of antioxidant phenolic compounds extracted from spent coffee grounds by freeze-drying and spray-drying using different coating materials

    DEFF Research Database (Denmark)

    Ballesteros, Lina F.; Ramirez, Monica J.; Orrego, Carlos E.

    2017-01-01

    Freeze-drying and spray-drying techniques were evaluated for encapsulation of phenolic compounds (PC) extracted from spent coffee grounds. Additionally, the use of maltodextrin, 29 gum arabic and a mixture of these components (ratio 1:1) as wall material to retain the PC and preserve...

  5. Production of freeze-dried lactic acid bacteria starter culture for cassava fermentation into gari

    CSIR Research Space (South Africa)

    Yao, AA

    2009-10-01

    Full Text Available . One of the most popular foods derived from fermented cassava is gari, consumed by nearly 200 million people in West Africa (Okafor and Ejiofor, 1990). Its cheapness, longer shelf- life, lower bulk (compared with other cassava products) and ease... water in the double jacket of the bioreactor and then concentrated 20 times by centrifugation (3000 ×g, 30 min). The cell suspension was supple- mented with 2% (w/w) and 5% (w/w) maltodextrin as protective compounds. The cells were freeze-dried in a...

  6. Inulin sugar glasses preserve the structural integrity and biological activity of influenza virosomes during freeze-drying and storage

    NARCIS (Netherlands)

    de Jonge, Jørgen; Amorij, Jean-Pierre; Hinrichs, Wouter L.J.; Wilschut, Jan; Huckriede, Anke; Frijlink, Henderik W.

    2007-01-01

    Influenza virosomes are reconstituted influenza virus envelopes that may be used as vaccines or as carrier systems for cellular delivery of therapeutic molecules. Here we present a procedure to generate influenza virosomes as a stable dry-powder formulation by freeze-drying (lyophilization) using an

  7. Nanomaterial transformation and association with fresh and freeze-dried wastewater activated sludge: implications for testing protocol and environmental fate.

    Science.gov (United States)

    Kiser, Mehlika A; Ladner, David A; Hristovski, Kiril D; Westerhoff, Paul K

    2012-07-03

    Engineered nanomaterials (ENMs) are an emerging class of contaminants entering wastewater treatment plants (WWTPs), and standardized testing protocols are needed by industry and regulators to assess the potential removal of ENMs during wastewater treatment. A United States Environmental Protection Agency (USEPA) standard method (OPPTS 835.1110) for estimating soluble pollutant removal during wastewater treatment using freeze-dried, heat-treated (FDH) activated sludge (AS) has been recently proposed for predicting ENM fate in WWTPs. This study is the first to evaluate the use of FDH AS in batch experiments for quantifying ENM removal from wastewater. While soluble pollutants sorbed equally to fresh and FDH AS, fullerene, silver, gold, and polystyrene nanoparticles' removals with FDH AS were approximately 60-100% less than their removals with fresh AS. Unlike fresh AS, FDH AS had a high concentration of proteins and other soluble organics in the liquid phase, an indication of bacterial membrane disintegration due to freeze-drying and heat exposure. This cellular matter stabilized ENMs such that they were poorly removed by FDH AS. Therefore, FDH AS is not a suitable sorbent for estimating nanoparticle removal in WWTPs, whereas fresh AS has been shown to reasonably predict full-scale performance for titanium removal. This study indicates that natural or engineered processes (e.g., anaerobic digestion, biosolids decomposition in soils) that result in cellular degradation and matrices rich in surfactant-like materials (natural organic matter, proteins, phospholipids, etc.) may transform nanoparticle surfaces and significantly alter their fate in the environment.

  8. Microencapsulation by freeze-drying of potassium norbixinate and curcumin with maltodextrin: stability, solubility, and food application.

    Science.gov (United States)

    Sousdaleff, Mirian; Baesso, Mauro Luciano; Medina Neto, Antonio; Nogueira, Ana Cláudia; Marcolino, Vanessa Aparecida; Matioli, Graciette

    2013-01-30

    Stability of potassium norbixinate and curcumin by microencapsulation with maltodextrin DE20 and freeze-drying was evaluated as a function of exposition to light, air, different pH, water solubility, and in food applications. The best results were obtained with microencapsulated potassium norbixinate 1:20, which, when vacuum-packed and in the presence of natural light, showed color retention of 78%, while microencapsulated curcumin 1:20 showed color retention of 71%. Differential scanning calorimetry and thermogravimetry provided an indication of interaction between colorants and maltodextrin. Photoacoustic spectroscopy (PAS) showed that free and microencapsulated colorants exhibited high rates of absorption throughout the measured spectral region. This work evidenced that the freeze-drying process is favorable for microencapsulation of curcumin by maltodextrin, providing improved solubility to the microencapsulated colorant. Both microencapsulated colorants showed relevant results for use in a wide range of pH and food applications. The PAS technique was useful for the evaluation of the stability of free and microencapsulated colorants.

  9. Effects of industrial pre-freezing processing and freezing handling on glucosinolates and antioxidant attributes in broccoli florets.

    Science.gov (United States)

    Cai, Congxi; Miao, Huiying; Qian, Hongmei; Yao, Leishuan; Wang, Bingliang; Wang, Qiaomei

    2016-11-01

    The effects of industrial pre-freezing processing and freezing handling on the contents of glucosinolates and antioxidants (vitamin C, polyphenols, carotenoid and chlorophyll), as well as the antioxidant capacity in broccoli (Brassica oleracea L. var. italica) florets were investigated in the present study. Our results showed that the glucosinolate accumulations were significantly decreased after pre-freezing processing, whereas elevated levels of phenols, carotenoids, chlorophyll, and also antioxidant capacity were observed in frozen broccoli florets. The contents of vitamin C remained constant during above mentioned processing. In conclusion, the current industrial freezing processing method is a good practice for the preservation of main antioxidant nutrients in broccoli florets, although some improvements in pre-freezing processing, such as steam blanching and ice-water cooling, are needed to attenuate the decrease in glucosinolate content.

  10. PREPARATION OF POROUS NANOCOMPOSITE SCAFFOLDS WITH HONEYCOMB MONOLITH STRUCTURE BY ONE PHASE SOLUTION FREEZE DRYING METHOD

    Institute of Scientific and Technical Information of China (English)

    Yang Xu; Duo Zhang; Zong-liang Wang; Zhan-tuan Gao; Pei-biao Zhang; Xue-si Chen

    2011-01-01

    Biodegradable porous nanocomposite scaffolds of poly(lactide-co-glycolide) (PLGA) and L-lactic acid (LAc) oligomer surface-grafted hydroxyapatite nanoparticles (op-HA) with a honeycomb monolith structure were fabricated with the single-phase solution freeze-drying method. The effects of different freezing temperatures on the properties of the scaffolds, such as microstructures, compressive strength, cell penetration and cell proliferation were studied. The highly porous and well interconnected scaffolds with a tunable pore structure were obtained. The effect of different freezing temperature (4℃, -20℃, -80℃ and -196℃) was investigated in relation to the scaffold morphology, the porosity varied from 91.2% to 83.0% and the average pore diameter varied from (167.2 ± 62.6) pm to (11.9 ± 4.2) μm while the σ10 increased significantly. The cell proliferation were decreased and associated with the above-mentioned properties. Uniform distribution of op-HA particles and homogeneous roughness of pore wall surfaces were found in the 4℃ frozen scaffold. The 4℃ frozen scaffold exhibited better cell penetration and increased cell proliferation because of its larger pore size, higher porosity and interconnection. The microstmctures described here provide a new approach for the design and fabrication of op-HA/PLGA based scaffold materials with potentially broad applicability for replacement of bone defects.

  11. Composition, thermotropic properties, and oxidative stability of freeze-dried and spray-dried milk fat globule membrane isolated from cheese whey.

    Science.gov (United States)

    Zhu, Dan; Damodaran, Srinivasan

    2011-08-24

    The milk fat globule membrane (MFGM) was isolated from cheese whey using a recently developed novel method. The cheese-derived MFGM contained about 17-19% lipids and 65-70% protein on a dry weight basis. About 50% of the lipids in MFGM were phospholipids. Compositional analysis of the cheese whey-derived MFGM showed that it is a rich source of phosphatidylserine, sphingomyelin, and bioactive proteins CD36, butyrophilin, xanthine oxidase, and mucin 1. Utilization of MFGM in foods as a source of nutraceutical lipids depends on its oxidative stability. In this context, the impact of drying methods, namely, freeze-drying versus spray-drying, on the storage stability of MFGM was studied. Freeze-dried (FD) and spray-dried (SD) MFGM samples were morphologically very different when examined by light microscope: The thermotropic phase transition temperature (T(m)) of lipids in the FD-MFGM was 37.8 °C, and it was 48 °C in SD-MFGM. This 10 °C difference in T(m) indicated that the drying method altered the thermodynamic state of phospholipids in MFGM. At all storage temperatures studied, the zero-order rate constant of lipid oxidation, as measured by hexanal production, was 1-2 orders of magnitude greater in the spray-dried than in the freeze-dried MFGM. The results clearly indicated that the choice of drying method affects morphological characteristics, the T(m) and oxidative stability of phospholipids in MFGM.

  12. Elemental distribution and sample integrity comparison of freeze-dried and frozen-hydrated biological tissue samples with nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Vavpetič, P., E-mail: primoz.vavpetic@ijs.si [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Vogel-Mikuš, K. [Biotechnical Faculty, Department of Biology, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana (Slovenia); Jeromel, L. [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Ogrinc Potočnik, N. [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); FOM-Institute AMOLF, Science Park 104, 1098 XG Amsterdam (Netherlands); Pongrac, P. [Biotechnical Faculty, Department of Biology, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana (Slovenia); Department of Plant Physiology, University of Bayreuth, Universitätstr. 30, 95447 Bayreuth (Germany); Drobne, D.; Pipan Tkalec, Ž.; Novak, S.; Kos, M.; Koren, Š.; Regvar, M. [Biotechnical Faculty, Department of Biology, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana (Slovenia); Pelicon, P. [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia)

    2015-04-01

    The analysis of biological samples in frozen-hydrated state with micro-PIXE technique at Jožef Stefan Institute (JSI) nuclear microprobe has matured to a point that enables us to measure and examine frozen tissue samples routinely as a standard research method. Cryotome-cut slice of frozen-hydrated biological sample is mounted between two thin foils and positioned on the sample holder. The temperature of the cold stage in the measuring chamber is kept below 130 K throughout the insertion of the samples and the proton beam exposure. Matrix composition of frozen-hydrated tissue is consisted mostly of ice. Sample deterioration during proton beam exposure is monitored during the experiment, as both Elastic Backscattering Spectrometry (EBS) and Scanning Transmission Ion Microscopy (STIM) in on–off axis geometry are recorded together with the events in two PIXE detectors and backscattered ions from the chopper in a single list-mode file. The aim of this experiment was to determine differences and similarities between two kinds of biological sample preparation techniques for micro-PIXE analysis, namely freeze-drying and frozen-hydrated sample preparation in order to evaluate the improvements in the elemental localisation of the latter technique if any. In the presented work, a standard micro-PIXE configuration for tissue mapping at JSI was used with five detection systems operating in parallel, with proton beam cross section of 1.0 × 1.0 μm{sup 2} and a beam current of 100 pA. The comparison of the resulting elemental distributions measured at the biological tissue prepared in the frozen-hydrated and in the freeze-dried state revealed differences in elemental distribution of particular elements at the cellular level due to the morphology alteration in particular tissue compartments induced either by water removal in the lyophilisation process or by unsatisfactory preparation of samples for cutting and mounting during the shock-freezing phase of sample preparation.

  13. Elemental distribution and sample integrity comparison of freeze-dried and frozen-hydrated biological tissue samples with nuclear microprobe

    Science.gov (United States)

    Vavpetič, P.; Vogel-Mikuš, K.; Jeromel, L.; Ogrinc Potočnik, N.; Pongrac, P.; Drobne, D.; Pipan Tkalec, Ž.; Novak, S.; Kos, M.; Koren, Š.; Regvar, M.; Pelicon, P.

    2015-04-01

    The analysis of biological samples in frozen-hydrated state with micro-PIXE technique at Jožef Stefan Institute (JSI) nuclear microprobe has matured to a point that enables us to measure and examine frozen tissue samples routinely as a standard research method. Cryotome-cut slice of frozen-hydrated biological sample is mounted between two thin foils and positioned on the sample holder. The temperature of the cold stage in the measuring chamber is kept below 130 K throughout the insertion of the samples and the proton beam exposure. Matrix composition of frozen-hydrated tissue is consisted mostly of ice. Sample deterioration during proton beam exposure is monitored during the experiment, as both Elastic Backscattering Spectrometry (EBS) and Scanning Transmission Ion Microscopy (STIM) in on-off axis geometry are recorded together with the events in two PIXE detectors and backscattered ions from the chopper in a single list-mode file. The aim of this experiment was to determine differences and similarities between two kinds of biological sample preparation techniques for micro-PIXE analysis, namely freeze-drying and frozen-hydrated sample preparation in order to evaluate the improvements in the elemental localisation of the latter technique if any. In the presented work, a standard micro-PIXE configuration for tissue mapping at JSI was used with five detection systems operating in parallel, with proton beam cross section of 1.0 × 1.0 μm2 and a beam current of 100 pA. The comparison of the resulting elemental distributions measured at the biological tissue prepared in the frozen-hydrated and in the freeze-dried state revealed differences in elemental distribution of particular elements at the cellular level due to the morphology alteration in particular tissue compartments induced either by water removal in the lyophilisation process or by unsatisfactory preparation of samples for cutting and mounting during the shock-freezing phase of sample preparation.

  14. Characterisation of Aronia powders obtained by different drying processes.

    Science.gov (United States)

    Horszwald, Anna; Julien, Heritier; Andlauer, Wilfried

    2013-12-01

    Nowadays, food industry is facing challenges connected with the preservation of the highest possible quality of fruit products obtained after processing. Attention has been drawn to Aronia fruits due to numerous health promoting properties of their products. However, processing of Aronia, like other berries, leads to difficulties that stem from the preparation process, as well as changes in the composition of bioactive compounds. Consequently, in this study, Aronia commercial juice was subjected to different drying techniques: spray drying, freeze drying and vacuum drying with the temperature range of 40-80 °C. All powders obtained had a high content of total polyphenols. Powders gained by spray drying had the highest values which corresponded to a high content of total flavonoids, total monomeric anthocyanins, cyaniding-3-glucoside and total proanthocyanidins. Analysis of the results exhibited a correlation between selected bioactive compounds and their antioxidant capacity. In conclusion, drying techniques have an impact on selected quality parameters, and different drying techniques cause changes in the content of bioactives analysed. Spray drying can be recommended for preservation of bioactives in Aronia products. Powder quality depends mainly on the process applied and parameters chosen. Therefore, Aronia powders production should be adapted to the requirements and design of the final product.

  15. Structural determinants of hydration, mechanics and fluid flow in freeze-dried collagen scaffolds.

    Science.gov (United States)

    Offeddu, G S; Ashworth, J C; Cameron, R E; Oyen, M L

    2016-09-01

    Freeze-dried scaffolds provide regeneration templates for a wide range of tissues, due to their flexibility in physical and biological properties. Control of structure is crucial for tuning such properties, and therefore scaffold functionality. However, the common approach of modeling these scaffolds as open-cell foams does not fully account for their structural complexity. Here, the validity of the open-cell model is examined across a range of physical characteristics, rigorously linking morphology to hydration and mechanical properties. Collagen scaffolds with systematic changes in relative density were characterized using Scanning Electron Microscopy, X-ray Micro-Computed Tomography and spherical indentation analyzed in a time-dependent poroelastic framework. Morphologically, all scaffolds were mid-way between the open- and closed-cell models, approaching the closed-cell model as relative density increased. Although pore size remained constant, transport pathway diameter decreased. Larger collagen fractions also produced greater volume swelling on hydration, although the change in pore diameter was constant, and relatively small at ∼6%. Mechanically, the dry and hydrated scaffold moduli varied quadratically with relative density, as expected of open-cell materials. However, the increasing pore wall closure was found to determine the time-dependent nature of the hydrated scaffold response, with a decrease in permeability producing increasingly elastic rather than viscoelastic behavior. These results demonstrate that characterizing the deviation from the open-cell model is vital to gain a full understanding of scaffold biophysical properties, and provide a template for structural studies of other freeze-dried biomaterials. Freeze-dried collagen sponges are three-dimensional microporous scaffolds that have been used for a number of exploratory tissue engineering applications. The characterization of the structure-properties relationships of these scaffolds is

  16. Influence of crystallizing and non-crystallizing cosolutes on trehalose crystallization during freeze-drying.

    Science.gov (United States)

    Sundaramurthi, Prakash; Suryanarayanan, Raj

    2010-11-01

    To study the influence of crystallizing and non-crystallizing cosolutes on the crystallization behavior of trehalose in frozen solutions and to monitor the phase behavior of trehalose dihydrate and mannitol hemihydrate during drying. Trehalose (a lyoprotectant) and mannitol (a bulking agent) are widely used as excipients in freeze-dried formulations. Using differential scanning calorimetry (DSC) and X-ray diffractometry (XRD), the crystallization behavior of trehalose in the presence of (i) a crystallizing (mannitol), (ii) a non-crystallizing (sucrose) solute and (iii) a combination of mannitol and a model protein (lactose dehydrogenase, catalase, or lysozyme) was evaluated. By performing the entire freeze-drying cycle in the sample chamber of the XRD, the phase behavior of trehalose and mannitol were simultaneously monitored. When an aqueous solution containing trehalose (4% w/v) and mannitol (2% w/v) was cooled to -40°C at 0.5°C/min, hexagonal ice was the only crystalline phase. However, upon warming the sample to the annealing temperature (-18°C), crystallization of mannitol hemihydrate was readily evident. After 3 h of annealing, the characteristic XRD peaks of trehalose dihydrate were also observed. The DSC heating curve of frozen and annealed solution showed two overlapping endotherms, attributed by XRD to the sequential melting of trehalose dihydrate-ice and mannitol hemihydrate-ice eutectics, followed by ice melting. While mannitol facilitated trehalose dihydrate crystallization, sucrose completely inhibited it. In the presence of protein (2 mg/ml), trehalose crystallization required a longer annealing time. When the freeze-drying was performed in the sample chamber of the diffractometer, drying induced the dehydration of trehalose dihydrate to amorphous anhydrate. However, the final lyophiles prepared in the laboratory lyophilizer contained trehalose dihydrate and mannitol hemihydrate. Using XRD and DSC, the sequential crystallization of ice, mannitol

  17. Factors influencing the stability of freeze-dried stress-resilient and stress-sensitive strains of bifidobacteria.

    Science.gov (United States)

    Celik, O F; O'Sullivan, D J

    2013-06-01

    Freeze-drying is a common method for preservation of probiotics, including bifidobacteria, for further industrial applications. However, the stability of freeze-dried bifidobacteria varies depending on the freeze-drying method and subsequent storage conditions. The primary goals of this study were to develop an optimized freeze-drying procedure and to determine the effects of temperature, water activity, and atmosphere on survival of freeze-dried bifidobacteria. To address these goals, a commercially used bifidobacteria strain that is resilient to stress, Bifidobacterium animalis ssp. lactis Bb-12, and a characterized intestinal strain that is more sensitive to stress conditions, Bifidobacterium longum DJO10A, were used. A freeze-drying protocol was developed using trehalose as the cryoprotectant, which resulted in almost no loss of viability during freeze-drying. Resuscitation medium, temperature, and time did not significantly influence recovery rates when this cryoprotectant was used. The effects of temperature (-80 to 45°C), water activity (0.02 to 0.92), and atmosphere (air, vacuum, and nitrogen) were evaluated for the stability of the freeze-dried powders during storage. Freeze-dried B. animalis ssp. lactis Bb-12 was found to survive under all conditions tested, with optimum survival at temperatures up to 21°C, water activities up to 0.44, and all 3 atmospheres tested. The intestinal-adapted strain B. longum DJO10A was much more sensitive to the different storage conditions, but could be adequately maintained using optimum conditions. These optimum storage conditions included frozen storage, replacement of oxygen with nitrogen, and water activities between 0.11 and 0.22. These results indicated that an optimized storage environment is required to maintain viability of stress-sensitive bifidobacteria strains, whereas stress-resilient bifidobacteria strains can maintain viability over a wide range of storage conditions, which is practical in countries where

  18. Development of freeze-dried DOTMP kits for labeling with {sup 68} Ga

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jae Cheong; Choi, Sang Mu; Cho, Eun Ha; Lee, So Young; Dho, So Hee; Kim, Soo Yong [Radioisotope Research Division, Dept. of Research Reactor Utilization, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Lyophilized dotMP kits were prepared using dotMP, ammonium acetate, and ascorbic acid. the {sup 68}Ga-dotMP was prepared by incubating the kit dissolved in 0.5 ml of concentrated {sup 68}Ga using nacl method and 0.5 ml of ddW, at 100 degrees C for 7 min. the labeling yield was evaluated by two solvent systems of tLc. 1 MBq of concentrated {sup 68}Ga was labeled with 0.8 μg of DOTMP by high radiolabeling yield (>98%), which was determined by two tLc methods. the composition of the prepared freeze-dried vial is 400 μg of DOTMP, 19.27 mg of ammonium acetate and 17.62 mg of ascorbic acid. ⁓555 MBq of {sup 68}Ga-dotMP was prepared with excellent radiochemical purity (>98%) and it was stable for 4 hr at room temperature. In conclusion, Freeze-dried dotMP kits for the convenient preparation of {sup 68}Ga-dotMP have been developed. Availability of this kit is expected to stimulate the widespread use of {sup 68}Ga-DOTMP in the fields of nuclear medicine.

  19. Development of a freeze-dried fungal wettable powder preparation able to biodegrade chlorpyrifos on vegetables.

    Directory of Open Access Journals (Sweden)

    Jie Liu

    Full Text Available Continuous use of the pesticide chlorpyrifos has resulted in harmful contaminations in environment and species. Based on a chlorpyrifos-degrading fungus Cladosporium cladosporioides strain Hu-01 (collection number: CCTCC M 20711, a fungal wettable powder preparation was developed aiming to efficiently remove chlorpyrifos residues from vegetables. The formula was determined to be 11.0% of carboxymethyl cellulose-Na, 9.0% of polyethylene glycol 6000, 5.0% of primary alcohol ethoxylate, 2.5% of glycine, 5.0% of fucose, 27.5% of kaolin and 40% of freeze dried fungi by response surface methodology (RSM. The results of quality inspection indicated that the fungal preparation could reach manufacturing standards. Finally, the degradation of chlorpyrifos by this fungal preparation was determined on pre-harvest cabbage. Compared to the controls without fungal preparation, the degradation of chlorpyrifos on cabbages, which was sprayed with the fungal preparation, was up to 91% after 7 d. These results suggested this freeze-dried fungal wettable powder may possess potential for biodegradation of chlorpyrifos residues on vegetables and provide a potential strategy for food and environment safety against pesticide residues.

  20. Optimization of freeze drying conditions for purified pectinase from mango (Mangifera indica cv. Chokanan) peel.

    Science.gov (United States)

    Mehrnoush, Amid; Mustafa, Shuhaimi; Yazid, Abdul Manap Mohd

    2012-01-01

    Response surface methodology (RSM) along with central composite design (CCD) was applied to optimize the freeze drying conditions for purified pectinase from mango (Mangifera indica cv. Chokanan) peel. The effect of pectinase content (-2.66, 62.66 mg/mL), Arabic gum (-1.21, 10.21%, w/v), and maltodextrin (0.73, 7.26%, w/v) as independent variables on activity, yield, and storage stability of freeze-dried enzyme was evaluated. Storage stability of pectinase was investigated after one week at 4 °C and yield percentage of the enzyme after encapsulation was also determined. The independent variables had the most significant (p mango peel were obtained using 30 mg/mL of pectinase content, 4.5 (%, w/v) of Arabic gum, and 4 (%, w/v) of maltodextrin. Under these conditions, the maximum activity (11.12 U/mL), yield (86.4%) and storage stability (84.2%) of encapsulated pectinase were achieved.

  1. Freeze-dried platelet-rich plasma shows beneficial healing properties in chronic wounds.

    Science.gov (United States)

    Pietramaggiori, Giorgio; Kaipainen, Arja; Czeczuga, Joshua M; Wagner, Christopher T; Orgill, Dennis P

    2006-01-01

    Fresh platelet concentrates are used in many centers to treat recalcitrant wounds. To extend the therapeutic shelf-life of platelets, we analyzed the wound-healing effects of fresh-frozen and freeze-dried (FD) platelet-rich plasma (PRP) using a diabetic mouse model. Db/db mice with 1.0 cm2 dorsal excisional wounds (n = 15/group) were treated with a single application of FD PRP (1.2 x 10(6) platelets/microL) with or without a stabilization solution, and compared with wounds treated with fresh-frozen, sonicated PRP, and untreated wounds. Granulation tissue area, thickness, and wound size were analyzed 9 days posttreatment. Immunostained sections were quantified for vascularity and proliferation using antiplatelet endothelial cell adhesion molecule I and antiproliferating cell nuclear antigen antibodies. The results showed that all PRP preparations increased granulation tissue formation as assessed by surface coverage, thickness, and angiogenic response, when compared with untreated wounds. In addition, wounds treated with FD PRP, and biochemically stabilized FD PRP, exhibited higher proliferative levels. The possibility to deliver growth factors using platelets, and the potential to extend the shelf-life of platelet concentrates makes freeze-drying methods particularly suitable for enhanced wound care.

  2. Freeze-drying of HI-6-loaded recombinant human serum albumin nanoparticles for improved storage stability.

    Science.gov (United States)

    Dadparvar, Miriam; Wagner, Sylvia; Wien, Sascha; Worek, Franz; von Briesen, Hagen; Kreuter, Jörg

    2014-10-01

    Severe intoxications with organophosphates require the immediate administration of atropine in combination with acetyl cholinesterase (AChE) reactivators such as HI-6. Although this therapy regimen enables the treatment of peripheral symptoms, the blood-brain barrier (BBB) restricts the access of the hydrophilic antidotes to the central nervous system which could lead to a fatal respiratory arrest. Therefore, HI-6-loaded albumin nanoparticles were previously developed to enhance the transport across this barrier and were able to reactivate organophosphate-(OP)-inhibited AChE in an in vitro BBB model. Since HI-6 is known to be moisture-sensitive, the feasibility of freeze-drying of the HI-6-loaded nanoparticles was investigated in the present study using different cryo- and lyoprotectants at different concentrations. Trehalose and sucrose (3%, w/v)-containing formulations were superior to mannitol concerning the physicochemical parameters of the nanoparticles whereas trehalose-containing samples were subject of a prolonged storage stability study at temperatures between -20°C and +40°C for predetermined time intervals. Shelf-life computations of the freeze-dried HI-6 nanoparticle formulations revealed a shelf-life time of 18 months when stored at -20°C. The formulations' efficacy was proven in vitro by reactivation of OP-inhibited AChE after transport over a porcine brain capillary endothelial cell layer model.

  3. Preparation of 3-D porous fibroin scaffolds by freeze drying with treatment of methanol solutions

    Institute of Scientific and Technical Information of China (English)

    ZHAN JingLin; SUN XiaoDan; CUI FuZhai; KONG XiangDong

    2007-01-01

    In this study,silk scaffolds with appropriate porous structures were prepared by adjusting solution concentrations and providing treatment with methanol solutions in the way of freeze drying. The effects of the preparation conditions on the microstructures and properties of the scaffolds were discussed. Fibroin solutions with different concentrations of 4,6,8,10 wt% were used respectively to prepare the scaffolds. The effects of the addition of 20 vol% methanol before or after freeze drying to the 4 wt% fibroin solution were investigated. As demonstrated by Scanning Electron Microscope (SEM),the fibroin scaffolds prepared without methanol had porous microstructures composed of thin sheets,and the sizes of the pores decreased with the increase of the fibroin solution concentrations,while the scaffolds prepared in the presence of methanol showed porous microstructures formed by fine-particle aggregates. The porosities and mechanical properties of the prepared fibroin scaffolds under different conditions were tested. The crystalline structures and conformations of the fibroin scaffolds were detected by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD).

  4. Freeze-dried snake antivenoms formulated with sorbitol, sucrose or mannitol: comparison of their stability in an accelerated test.

    Science.gov (United States)

    Herrera, María; Tattini, Virgilio; Pitombo, Ronaldo N M; Gutiérrez, José María; Borgognoni, Camila; Vega-Baudrit, José; Solera, Federico; Cerdas, Maykel; Segura, Alvaro; Villalta, Mauren; Vargas, Mariángela; León, Guillermo

    2014-11-01

    Freeze-drying is used to improve the long term stability of pharmaceutical proteins. Sugars and polyols have been successfully used in the stabilization of proteins. However, their use in the development of freeze-dried antivenoms has not been documented. In this work, whole IgG snake antivenom, purified from equine plasma, was formulated with different concentrations of sorbitol, sucrose or mannitol. The glass transition temperatures of frozen formulations, determined by Differential Scanning Calorimetry (DSC), ranged between -13.5 °C and -41 °C. In order to evaluate the effectiveness of the different stabilizers, the freeze-dried samples were subjected to an accelerated stability test at 40 ± 2 °C and 75 ± 5% relative humidity. After six months of storage at 40 °C, all the formulations presented the same residual humidity, but significant differences were observed in turbidity, reconstitution time and electrophoretic pattern. Moreover, all formulations, except antivenoms freeze-dried with mannitol, exhibited the same potency for the neutralization of lethal effect of Bothrops asper venom. The 5% (w:v) sucrose formulation exhibited the best stability among the samples tested, while mannitol and sorbitol formulations turned brown. These results suggest that sucrose is a better stabilizer than mannitol and sorbitol in the formulation of freeze-dried antivenoms under the studied conditions.

  5. NaCl stress impact on the key enzymes in glycolysis from Lactobacillus bulgaricus during freeze-drying

    Science.gov (United States)

    Li, Chun; Sun, Jinwei; Qi, Xiaoxi; Liu, Libo

    2015-01-01

    Abstract The viability of Lactobacillus bulgaricus in freeze-drying is of significant commercial interest to dairy industries. In the study, L.bulgaricus demonstrated a significantly improved (p < 0.05) survival rate during freeze-drying when subjected to a pre-stressed period under the conditions of 2% (w/v) NaCl for 2 h in the late growth phase. The main energy source for the life activity of lactic acid bacteria is related to the glycolytic pathway. To investigate the phenomenon of this stress-related viability improvement in L. bulgaricus, the activities and corresponding genes of key enzymes in glycolysis during 2% NaCl stress were studied. NaCl stress significantly enhanced (p < 0.05) glucose utilization. The activities of glycolytic enzymes (phosphofructokinase, pyruvate kinase, and lactate dehydrogenase) decreased during freeze-drying, and NaCl stress were found to improve activities of these enzymes before and after freeze-drying. However, a transcriptional analysis of the corresponding genes suggested that the effect of NaCl stress on the expression of the pfk2 gene was not obvious. The increased survival of freeze-dried cells of L. bulgaricus under NaCl stress might be due to changes in only the activity or translation level of these enzymes in different environmental conditions but have no relation to their mRNA transcription level. PMID:26691481

  6. Freeze-dried nifedipine-lipid nanoparticles with long-term nano-dispersion stability after reconstitution.

    Science.gov (United States)

    Ohshima, Hiroyuki; Miyagishima, Atsuo; Kurita, Takurou; Makino, Yuji; Iwao, Yasunori; Sonobe, Takashi; Itai, Shigeru

    2009-07-30

    Nifedipine (NI) is a poorly water-soluble drug and its oral bioavailability is very low. To improve the water solubility, NI-lipid nanoparticle suspensions were prepared by a combination of co-grinding by a roll mill and high-pressure homogenization without any organic solvent. The mean particle size and zeta potential of the NI-lipid nanoparticle suspensions were about 52.6 nm and -61.8 mV, respectively, and each parameter remained extremely constant during a period of 4 months under 6 degrees C and dark conditions, suggesting that the negative charge of the phospholipid, dipalmitoyl phosphatidylglycerol, is very effective in preventing coagulation of the particles. In order to assure the nano-order particle size of the suspensions in view of long-term stability, a freeze-drying technique was applied to the NI-lipid nanoparticle suspensions. The mean particle size of freeze-dried NI-lipid nanoparticles after reconstitution was significantly increased in comparison to that of the preparations before freeze-drying. It was found, however, that the addition of sugars (glucose, fructose, maltose or sucrose) to the suspensions before freeze-drying inhibited the aggregation of nanoparticles, suggesting that the long-term stability storage of freeze-dried NI-lipid nanoparticles after reconstitution would be overcome. In addition, freeze-dried nanoparticles with 100mg sugar (glucose, fructose, maltose or sucrose) showed excellent solubility (>80%), whereas without sugar, as a control, showed low solubility (coagulation of NI nanoparticle suspensions, and reproduce the nanoparticle dispersion after reconstitution; and remarkably increase the apparent solubility of nifedipine.

  7. Characterization of a laboratory-scale container for freezing protein solutions with detailed evaluation of a freezing process simulation.

    Science.gov (United States)

    Roessl, Ulrich; Jajcevic, Dalibor; Leitgeb, Stefan; Khinast, Johannes G; Nidetzky, Bernd

    2014-02-01

    A 300-mL stainless steel freeze container was constructed to enable QbD (Quality by Design)-compliant investigations and the optimization of freezing and thawing (F/T) processes of protein pharmaceuticals at moderate volumes. A characterization of the freezing performance was conducted with respect to freezing kinetics, temperature profiling, cryoconcentration, and stability of the frozen protein. Computational fluid dynamic (CFD) simulations of temperature and phase transition were established to facilitate process scaling and process analytics as well as customization of future freeze containers. Protein cryoconcentration was determined from ice-core samples using bovine serum albumin. Activity, aggregation, and structural perturbation were studied in frozen rabbit muscle l-lactic dehydrogenase (LDH) solution. CFD simulations provided good qualitative and quantitative agreement with highly resolved experimental measurements of temperature and phase transition, allowing also the estimation of spatial cryoconcentration patterns. LDH exhibited stability against freezing in the laboratory-scale system, suggesting a protective effect of cryoconcentration at certain conditions. The combination of the laboratory-scale freeze container with accurate CFD modeling will allow deeper investigations of F/T processes at advanced scale and thus represents an important step towards a better process understanding. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

  8. The use of a freeze-dried extract of Ligusticum mutellina in a cosmetic cream with potential antioxidant properties

    Directory of Open Access Journals (Sweden)

    Tomasz Baj

    2016-12-01

    Full Text Available The aim of this work was to develop a cream formulation with potential antioxidant properties. Herein, a freeze-dried extract of Ligusticum mutellina was used as a source of active compounds. The proposed qualitative composition of the cream was characterized by a good polyphenolic compounds release profile. Of note, the highest R2adj values were obtained for the Korsmeyer-Peppas and Higuchi models (0.9159 and 0.9226, respectively. These results indicate that a freeze-dried extract of L. mutellina, due to its retained high phenolic acids content, could become a key component in antioxidant creams.

  9. Improving Heat Transfer at the Bottom of Vials for Consistent Freeze Drying with Unidirectional Structured Ice.

    Science.gov (United States)

    Rosa, Mónica; Tiago, João M; Singh, Satish K; Geraldes, Vítor; Rodrigues, Miguel A

    2016-10-01

    The quality of lyophilized products is dependent of the ice structure formed during the freezing step. Herein, we evaluate the importance of the air gap at the bottom of lyophilization vials for consistent nucleation, ice structure, and cake appearance. The bottom of lyophilization vials was modified by attaching a rectified aluminum disc with an adhesive material. Freezing was studied for normal and converted vials, with different volumes of solution, varying initial solution temperature (from 5°C to 20°C) and shelf temperature (from -20°C to -40°C). The impact of the air gap on the overall heat transfer was interpreted with the assistance of a computational fluid dynamics model. Converted vials caused nucleation at the bottom and decreased the nucleation time up to one order of magnitude. The formation of ice crystals unidirectionally structured from bottom to top lead to a honeycomb-structured cake after lyophilization of a solution with 4% mannitol. The primary drying time was reduced by approximately 35%. Converted vials that were frozen radially instead of bottom-up showed similar improvements compared with normal vials but very poor cake quality. Overall, the curvature of the bottom of glass vials presents a considerable threat to consistency by delaying nucleation and causing radial ice growth. Rectifying the vials bottom with an adhesive material revealed to be a relatively simple alternative to overcome this inconsistency.

  10. Mechanism of protein stabilization by trehalose during freeze-drying analyzed by in situ micro-raman spectroscopy.

    Science.gov (United States)

    Hedoux, Alain; Paccou, Laurent; Achir, Samira; Guinet, Yannick

    2013-08-01

    Raman investigations were performed in situ during freeze-drying of two model proteins, lysozyme and chymotrypsinogen. The structures of proteins dissolved in 0-30 wt % solutions of trehalose in D2 O were monitored with the fingerprint (800-1800 cm(-1) ) spectrum, simultaneously with freezing, ice sublimation, and water desorption analyzed in the O-D stretching (2200-2700 cm(-1) ) region. In the absence of trehalose, the main changes were detected at the end of primary drying, and correspond to distortion and disordering of secondary structures. A stabilizing effect of trehalose was evidenced in primary and secondary drying stages. Raman images were calculated after freezing and primary drying, providing the distributions of trehalose, water, and protein which occur during the first two stages of the lyophilization cycle. Raman images show a slight heterogeneity in the degree of protein denaturation at the end of primary drying, in relation with the structure of the frozen product observed during freezing. The ability of trehalose to make the protein more rigid was determined as responsible for the protein stabilization during a lyophilization cycle.

  11. Physical characteristics of phycocyanin from spirulina microcapsules using different coating materials with freeze drying method

    Science.gov (United States)

    Dewi, E. N.; Purnamayati, L.; Kurniasih, R. A.

    2017-02-01

    The aim of this study was to compare the physical characteristics of phycocyanin microcapsules (F) from Spirulina sp. with different coating materials, such as κ-Carrageenan (C) and Na-alginate (A) in combination with maltodextrin (M) by freeze drying method. Microcapsules were prepared in three variations of coating materials i.e. maltodextrin (FM); maltodextrin and Na-alginate (FMA); and maltodextrin and carrageenan (FMC) with concentration of each materials were 10%; 9%:1.0%; and 9%:1% (w/w), respectively. The results showed that FMA with Na-alginate 1.0% produced the highest bulk density and total soluble solid, there were 0,334 g/ml and 9,067%, respectively. Color analysis by chromameter showed that FMC produced the bluest color compared to other samples. The glass transition temperature (Tg) investigated with Differential scanning calorimeter (DSC) in all of the samples.

  12. Study on the Effect of Pickled Cabbage using Freeze-drying Protective Agent

    Directory of Open Access Journals (Sweden)

    Xing Long

    2013-10-01

    Full Text Available The protective effect of pickled cabbage using biological material was researched in the study. Firstly, the research determined the centrifugal condition of bacterial sludge and then detected the influence of various protective agents on the survival rate of lactobacillus. The final test result can show the influence degree of various protective agents on the survival rate of the freeze-drying lactobacillus was sodium glutamate>skim milk>mannitol>sucrose>glycerol>maltose. The best formula of the protective agent was: the skim milk, sucrose, glycerol, maltose and sodium glutamate shall be 6% and the mannitol shall be 4%. The survival rate of the lactobacillus after using the sodium glutamate with the best protection effect can reach 65.5%. The experience proved that these protective agents and ratio can guarantee the nutrients in the pickled cabbage not destroyed.

  13. Thermal, Structural, and Physical Properties of Freeze Dried Tropical Fruit Powder

    Directory of Open Access Journals (Sweden)

    K. A. Athmaselvi

    2014-01-01

    Full Text Available This study evaluates the physical properties of freeze dried tropical (guava, sapota, and papaya fruit powders. Thermal stability and weight loss were evaluated using TGA-DSC and IR, which showed pectin as the main solid constituent. LCR meter measured electrical conductivity, dielectric constant, and dielectric loss factor. Functional groups assessed by FTIR showed presence of chlorides, and O–H and N–H bonds in guava, chloride and C–H bond in papaya, and chlorides, and C=O and C–H bonds in sapota. Particle size and type of starch were evaluated by X-ray diffraction and microstructure through scanning electronic microscopy. A semicrystalline profile and average particle size of the fruit powders were evidenced by X-ray diffraction and lamellar/spherical morphologies by SEM. Presence of A-type starch was observed in all three fruits. Dependence of electric and dielectric properties on frequency and temperature was observed.

  14. Mannitol/l-Arginine-Based Formulation Systems for Freeze Drying of Protein Pharmaceuticals: Effect of the l-Arginine Counter Ion and Formulation Composition on the Formulation Properties and the Physical State of Mannitol.

    Science.gov (United States)

    Stärtzel, Peter; Gieseler, Henning; Gieseler, Margit; Abdul-Fattah, Ahmad M; Adler, Michael; Mahler, Hanns-Christian; Goldbach, Pierre

    2016-10-01

    Previous studies have shown that protein storage stability in freeze-dried l-arginine-based systems improved in the presence of chloride ions. However, chloride ions reduced the glass transition temperature of the freeze concentrate (Tg') and made freeze drying more challenging. In this study, l-arginine was freeze dried with mannitol to obtain partially crystalline solids that can be freeze dried in a fast process and result in elegant cakes. We characterized the effect of different l-arginine counter ions on physicochemical properties of mannitol compared with mannitol/sucrose systems. Thermal properties of formulations with different compositions were correlated to thermal history during freeze drying and to physicochemical properties (cake appearance, residual moisture, reconstitution time, crystallinity). Partially crystalline solids were obtained even at the highest l-arginine level (mannitol:l-arginine of 2:1) used in this study. All l-arginine-containing formulations yielded elegant cakes. Only cakes containing l-arginine chloride and succinate showed a surface "crust" formed by phase separation. X-ray powder diffraction showed that inhibition of mannitol crystallization was stronger for l-arginine compared with sucrose and varied with the type of l-arginine counter ion. The counter ion affected mannitol polymorphism and higher levels of mannitol hemi-hydrate were obtained at high levels of l-arginine chloride.

  15. Spectroscopic evaluation of a freeze-dried vaccine during an accelerated stability study.

    Science.gov (United States)

    Hansen, Laurent; Van Renterghem, Jeroen; Daoussi, Rim; Vervaet, Chris; Remon, Jean Paul; De Beer, Thomas

    2016-07-01

    This research evaluates a freeze-dried live, attenuated virus vaccine during an accelerated stability study using Near Infrared (NIR) and Fourier Transform Infrared (FTIR) spectroscopy in addition to the traditional quality tests (i.e., potency assay and residual moisture analysis) and Modulated Differential Scanning Calorimetry (MDSC). Therefore, freeze-dried live, attenuated virus vaccines were stored during four weeks at 4°C (i.e., recommended storage condition) and at 37°C (i.e., accelerated storage condition) and weekly analyzed using these techniques. The potency assay showed that the virus titer decreased in two phases when the samples were stored at 37°C. The highest titer loss occurred during the first week storage at 37°C after which the degradation rate decreased. Both the residual moisture content and the relaxation enthalpy also increased according to this two-phase pattern during storage at 37°C. In order to evaluate the virus and its interaction with the amorphous stabilizer in the formulation (trehalose), the NIR spectra were analyzed via principal component analysis (PCA) using the amide A/II band (5029-4690cm(-1)). The FTIR spectra were also analyzed via PCA using the amide III spectral range (1350-1200cm(-1)). Analysis of the amide A/II band in the NIR spectra revealed that the titer decrease during storage was probably linked to a change of the hydrogen bonds (i.e., interaction) between the virus proteins and the amorphous trehalose. Analyzing the amide III band (FTIR spectra) showed that the virus destabilization was coupled to a decrease of the coated proteins β turn and an increase of α helix. During storage at 4°C, the titer remained constant, no enthalpic relaxation was observed and neither the Amide A/II band (NIR spectra) nor the Amide III band (FTIR spectra) varied.

  16. Freeze-dried Xanthan/Guar Gum Nasal Inserts for the Delivery of Metoclopramide Hydrochloride.

    Science.gov (United States)

    Dehghan, Mohamed Hassan; Girase, Mohan

    2012-01-01

    Prolonged residence of drug formulation in the nasal cavity is important for the enhancing intranasal drug delivery. The objective of the present study was to develop a mucoadhesive in-situ gelling nasal insert which would enable the reduced nasal mucociliary clearance in order to improve the bioavailability of metoclopramide hydrochloride. Metoclopramide hydrochloride is a potent antiemetic and effective for preventing emesis induced by cancer chemotherapy, migraine, pregnancy and gastroparesis. It undergoes hepatic first pass metabolism and both the absolute bioavailability and the plasma concentrations are subjected to wide inter-individual variation showing values between 32% and 98%. Oral antiemetic often gets vomited out before the systemic absorption compelling parenteral administration which results in low patient compliance. Adverse effect of metoclopramide HCL on CNS caused by high plasma peaks can be avoided through sustained formulation. A novel combination of xanthan gum and guar gum was used to prepare the nasal inserts and the effect of blend ratio of xanthan gum and guar gum on drug release from in-situ gelling nasal inserts and on other insert properties such as bioadhesion potential and water uptake was studied. PXRD was used to determine the effect of freeze-drying on crystalline nature of formulation. The viscosities of xanthan gum in combination with guar gum were observed to be higher than that of single polymer solutions. This is because of the synergistic rheological interaction between xanthan and guar gum. There is a substantial loss in crystalline nature of the formulation after freeze-drying. The best nasal inserts formulation containing xanthan gum and guar gum ratio 1:5, showed good release (91.83%) as well as bioadhesion which may result in an increase in the nasal residence time.

  17. Preparation and characterization of solid dispersion freeze-dried efavirenz – polyvinylpyrrolidone K-30

    Science.gov (United States)

    Fitriani, Lili; Haqi, Alianshar; Zaini, Erizal

    2016-01-01

    The aim of this research is to prepare and characterize solid dispersion of efavirenz – polyvinylpyrrolidone (PVP) K-30 by freeze drying to increase its solubility. Solid dispersion of efavirenz – PVP K-30 was prepared by solvent evaporation method with ratio 2:1, 1:1, and 1:2 and dried using a freeze dryer. Characterizations were done by scanning electron microscopy (SEM), powder X-ray diffraction analysis, differential thermal analysis (DTA), and Fourier transform infrared (FT-IR) spectroscopy. Solubility test was carried out in CO2-free distilled water, and efavirenz assay was conducted using high-performance liquid chromatography with acetonitrile:acetic acid (80:20) as the mobile phases. Powder X-ray diffractogram showed a decrease in the peak intensity, which indicated the crystalline altered to amorphous phase. DTA thermal analysis showed a decrease in the melting point of the solid dispersion compared to intact efavirenz. SEM results indicated the changes in the morphology of the crystal into an amorphous form compared to pure components. FT-IR spectroscopy analysis showed a shift wavenumber of the spectrum efavirenz and PVP K-30. The solubility of solid dispersion at ratio 2:1, 1:1, and 1:2 was 6.777 μg/mL, 6.936 μg/mL, and 14,672 μg/mL, respectively, whereas the solubility of intact efavirenz was 0.250 μg/mL. In conclusion, the solubility of solid dispersion increased significantly (P < 0.05). PMID:27429930

  18. The Effect of Non Freeze-dried Hydrogel-CHA on Fibroblast Proliferation

    Directory of Open Access Journals (Sweden)

    Ivan Arie Wahyudi

    2015-05-01

    Full Text Available Bone damage can be caused by variety of surgical procedures. Bone reconstruction has been developed lately is tissue engineering techniques. One of materials that proved to be effective as a scaffold in tissue engineering is a hydrogel. The addition of carbonate apatite (CHA will produce a hydrogel-CHA material which is believed to improve the mechanical properties and biological similarities with the original bone. Scaffold is considered an important aspect in the field of tissue engineering, because it’s ability to mimic extracellular matrix of the damaged tissue. Fibroblasts are mesenchymal cells that can be readily cultured in the laboratory and play a significant role in epithelial-mesenchymal interactions, secreting various growth factors and cytokines. On certain condition, Fibroblast will differentiate into bone-forming cells, osteoblasts. Objective: to determine the effect of non freezedried hydrogels - CHA on the number of fibroblasts. Methods: In the treatment groups (hydrogel and hydrogel-CHA group, the static seeding, where cells and scaffolds were simply brought into contact, was performed. The other group contained only cells and growth media. Cells were seeded at a density of 2x104 cells/ml in a 96-well plate. Number of fibroblasts cell in each group was observed by light microscopy and quantitified by MTT assay on days 1, 2 and 3 post-application. Results: Proliferation of fibroblasts increased significantly on day 3rd after application of non freeze-dried hydrogel - CHA (p< 0.05. Conclusion: Application of non freeze-dried hydrogel - CHA may induce fibroblasts proliferation.

  19. Quality of freeze-dried (lyophilized) quarantined single-donor plasma.

    Science.gov (United States)

    Bux, Jürgen; Dickhörner, Dieter; Scheel, Edgar

    2013-12-01

    Transfusion of plasma is a basic treatment for complex coagulopathies as well as in major blood loss. Early transfusion of plasma after trauma with major hemorrhage has been recommended by retrospective studies. However, the use of plasma is often hampered by the need to maintain a cold chain and the time needed for thawing fresh-frozen plasma (FFP). With freeze-dried (lyophilized) plasma (FDP) both difficulties can be avoided. Here, we describe the production, quality characteristics, and our experiences with FDP. Quarantine plasma samples were freeze-dried. The clotting factors fibrinogen, Factor (F)V, FVIII, FXI, von Willebrand factor (vWF), protein S, antithrombin, plasminogen, and plasmin inhibitor were determined after manufacturing and after storage at room temperature and refrigeration. Reported adverse transfusion events were evaluated and compared to that of FFP. Clinical effectiveness was estimated by inquiry among experienced users. Lyophilization resulted in a loss of coagulation factor activity between 0% and up to 20% to 25% (FVIII, vWF). When stored refrigerated, coagulation factors did not lose more than 10% of their activities. Storage at room temperature for 24 months mainly affected vWF/ristocetin cofactor activity and fibrinogen activity. From 2007 to 2011 more than 230,000 units of FDP were delivered. There were no reports about clinical ineffectiveness. The frequency of transfusion reactions was not different from that of FFP. Lyophilized plasma showed characteristics similar to FFP. Since FDP requires neither complex logistics nor time-consuming thawing, it allows rapid treatment of coagulopathies. © 2013 American Association of Blood Banks.

  20. Effect of allogenic freeze-dried demineralized bone matrix on guided tissue regeneration in dogs.

    Science.gov (United States)

    Caplanis, N; Lee, M B; Zimmerman, G J; Selvig, K A; Wikesjö, U M

    1998-08-01

    This randomized, split-mouth study was designed to evaluate the adjunctive effect of allogenic, freeze-dried, demineralized bone matrix (DBM) to guided tissue regeneration (GTR). Contralateral fenestration defects (6 x 4 mm) were created 6 mm apical to the buccal alveolar crest on maxillary canine teeth in 6 beagle dogs. DBM was implanted into one randomly selected fenestration defect. Expanded polytetrafluoroethylene (ePTFE) membranes were used to provide bilateral GTR. Tissue blocks including defects with overlying membranes and soft tissues were harvested following a four-week healing interval and prepared for histometric analysis. Differences between GTR+DBM and GTR defects were evaluated using a paired t-test (N = 6). DBM was discernible in all GTR+DBM defects with limited, if any, evidence of bone metabolic activity. Rather, the DBM particles appeared solidified within a dense connective tissue matrix, often in close contact to the instrumented root. There were no statistically significant differences between the GTR+DBM versus the GTR condition for any histometric parameter examined. Fenestration defect height averaged 3.7+/-0.3 and 3.9+/-0.3 mm, total bone regeneration 0.8+/-0.6 and 1.5+/-0.8 mm, and total cementum regeneration 2.0+/-1.3 and 1.6+/-1.7 mm for GTR+DBM and GTR defects, respectively. The histologic and histometric observations, in concert, suggest that allogenic freeze-dried DBM has no adjunctive effect to GTR in periodontal fenestration defects over a four-week healing interval. The critical findings were 1) the DBM particles remained, embedded in dense connective tissue without evidence of bone metabolic activity; and 2) limited and similar amounts of bone and cementum regeneration were observed for both the GTR+DBM and GTR defects.

  1. Effect of Microencapsulation by Spray-Drying and Freeze-Drying Technique on the Antioxidant Properties of Blueberry (Vaccinium myrtillus Juice Polyphenolic Compounds

    Directory of Open Access Journals (Sweden)

    Wilkowska Agnieszka

    2016-03-01

    Full Text Available Blueberry juice with high polyphenol concentration was spray- or freeze-dried using different coating materials: HP-β-cyclodextrin and β-cyclodextrin. The quality of the obtained powders was characterised by their anthocyanin content, total polyphenols and antioxidant capacity. SEM was used for monitoring structures and size (2–20 μm of the microparticles. The losses of total phenolic compounds during spray-drying reached 76–78% on average, while these of anthocyanins about 57%. Freeze-dried powders showed better retention values of anthocyanins, which was about 1.5-fold higher than for the spray-dried counterparts. All blueberry preparations studied were characterised by very high radical scavenging activity.

  2. Study on the vacuum characteristics of a freeze-drying chamber for mannitol%甘露醇冷冻干燥室内真空压力特性的研究

    Institute of Scientific and Technical Information of China (English)

    夏鹏

    2011-01-01

    The vacuum system of a freeze-drying chamber provide an environment for the freeze-drying process, so the vacuum characteristics are a vital issue in the process. Taking the mannitol freeze-drying for an example, the characteristics of the vacuum freeze-drying chamber was studied in three ways: The influence of vacuum pressure on the mass weighing of the freeze-drying materials; The effect of vacuum pressure on the temperature in the freeze-drying bottle; The influence of vacuum on the primary drying rate of the freeze-drying materials. It was concluded that in the vacuum environment, the materials weighing can be used to judge whether the first drying process is ended or not. In view of the mannitol freeze-drying process, if the vacuum chamber is maintained at lPa, high quality drying products can be ensured, and meanwhile the heat transfer process is even.%冷冻干燥室的真空系统为冷冻干燥提供了真空环境,真空压力特性对冷冻干燥过程顺利进行至关重要,本文以甘露醇溶液的冷冻干燥过程为例,从三个方面对冷冻干燥室内真空压力特性进行了研究:一、真空度对冷冻干燥物料质量称量的影响;二、真空度对冷冻干燥物料瓶内温度的影响;三、真空度对冷冻干燥物料一次干燥速率的影响.通过实验,得出结论:真空环境下,物料质量的称量值可用来判断一次干燥过程是否结束.针对甘露醇溶液的冻干工艺,将冻干室的真空压力维持在1Pa可以保证干燥物料的质量,同时该工艺过程传热均匀.

  3. Enhancing the aqueous solubility and dissolution of olanzapine using freeze-drying

    Directory of Open Access Journals (Sweden)

    Mudit Dixit

    2011-12-01

    Full Text Available The aim of the present study was to develop an olanzapine freeze-dried tablet (FDT. The solubility and dissolution rate of poorly water-soluble olanzapine was improved by preparing a freeze-dried tablet of olanzapine using the freeze-drying technique . The FDT was prepared by dispersing the drug in an aqueous solution of highly water-soluble carrier materials consisting of gelatin, glycine, and sorbitol. The mixture was poured in to the pockets of blister packs and then was subjected to freezing and lyophilisation. The FDT was characterised by DSC, XRD and SEM and was evaluated for saturation solubility and dissolution. The samples were stored in a stability chamber to investigate their physical stability. Results obtained by DSC and X-ray were analysed and showed the crystalline state of olanzapine in FDT transformation to the amorphous state during the formation of FDT. Scanning electron microscope (SEM results suggest reduction in olanzapine particle size. The solubility of olanzapine from the FDT was observed to be nearly four and a half times greater than the pure drug. Results obtained from dissolution studies showed that olanzapine FDT significantly improved the dissolution rate of the drug compared with the physical mixture (PM and the pure drug. More than 90% of olanzapine in FDT dissolved within 5 minutes, compared to only 19.78% of olanzapine pure drug dissolved over the course of 60 minutes. In a stability test, the release profile of the FDT was unchanged, as compared to the freshly prepared FDT after 90 days of storing.O objetivo do presente estudo foi desenvolver comprimidos liofilizados de olanzapina (FDT. A solubilidade e a taxa de dissolução da olanzapina, fracamente solúvel em água, foram melhoradas com a preparação de comprimidos liofilizados de olanzapina usando a técnica de liofilização. O FDT foi preparado por dispersão do fármaco em solução aquosa de materiais altamente solúveis em água, como gelatina

  4. Freeze-drying of “pearl milk tea”: A general strategy for controllable synthesis of porous materials

    Science.gov (United States)

    Zhou, Yingke; Tian, Xiaohui; Wang, Pengcheng; Hu, Min; Du, Guodong

    2016-05-01

    Porous materials have been widely used in many fields, but the large-scale synthesis of materials with controlled pore sizes, pore volumes, and wall thicknesses remains a considerable challenge. Thus, the controllable synthesis of porous materials is of key general importance. Herein, we demonstrate the “pearl milk tea” freeze-drying method to form porous materials with controllable pore characteristics, which is realized by rapidly freezing the uniformly distributed template-containing precursor solution, followed by freeze-drying and suitable calcination. This general and convenient method has been successfully applied to synthesize various porous phosphate and oxide materials using different templates. The method is promising for the development of tunable porous materials for numerous applications of energy, environment, and catalysis, etc.

  5. Thermal ink-jet spray freeze-drying for preparation of excipient-free salbutamol sulphate for inhalation.

    Science.gov (United States)

    Mueannoom, Wunlapa; Srisongphan, Amon; Taylor, Kevin M G; Hauschild, Stephan; Gaisford, Simon

    2012-01-01

    The use of thermal ink-jet spray freeze-drying (TIJ-SFD) to engineer inhalable, excipient-free salbutamol sulphate (SS) particles was assessed. A modified Hewlett-Packard printer was used to atomise aqueous SS solutions into liquid nitrogen. The frozen droplets were freeze-dried. It was found that TIJ-SFD could process SS solutions up to 15%w/v; the porous particles produced had a physical diameter of ca. 35 μm. Next generation impactor (NGI) analysis indicated that the particles had a smaller aerodynamic size (MMAD ranging from 6 to 8.7 μm). Particles prepared from the lowest concentration SS solution were too fragile to withstand aerosolisation, but the 5%w/v solution yielded particles having the best combination of strength and aerodynamic properties. Comparison with a commercial SS formulation (Cyclocap®) showed that the SFD preparation had an almost equivalent FPF (6.4 μm) when analysed with a twin-stage impinger (TSI; 24.0 ± 1.2% and 26.4 ± 2.2%, respectively) and good performance when analysed with NGI (FPF (4.46 μm):16.5 ± 2.0 and 27.7 ± 1.7, respectively). TIJ-SFD appears to be an excellent method to prepare inhalable particles. It is scalable yet allows assessment of the viability of the pulmonary route early in the development since it can be used with very small volumes (<0.5 mL) of solution.

  6. 微波及辐射真空干燥过程中的干燥动力学及能量消耗%Drying Kinetics and Energy Consumption in Vacuum Drying Process with Microwave and Radiant Heating

    Institute of Scientific and Technical Information of China (English)

    M. Kamel; J.I. Lombra(n)a; C. de Elvira; R. Rodr(i)guez

    2004-01-01

    The general objective of this work is to analyze energy input in a vacuum process with the incorporation of microwave heating. Thus, necessary criteria for designing an efficient freeze-drying operation are considered through the analysis of strategies based on the combination of different intensities of radiant and microwave heating.The other aim of this research topic is to study the kinetics of drying in relation to mass transfer parameters.Five freeze-drying strategies using both heating systems were used. Consequently, energy input could be related to diffusivity coefficients, temperature and pressure profiles during dehydration of the product and analyzed in comparison to a conventional freeze-drying process.

  7. Development of a Mini-Freeze Dryer for Material-Sparing Laboratory Processing with Representative Product Temperature History.

    Science.gov (United States)

    Obeidat, Wasfy M; Sahni, Ekneet; Kessler, William; Pikal, Michael

    2017-09-13

    The goal of the work described in this publication was to evaluate a new, small, material-sparing freeze dryer, denoted as the "mini-freeze dryer or mini-FD", capable of reproducing the product temperature history of larger freeze dryers, thereby facilitating scale-up. The mini-FD wall temperatures can be controlled to mimic loading procedures and dryer process characteristics of larger dryers. The mini-FD is equipped with a tunable diode laser absorption spectroscopy (TDLAS) water vapor mass flow monitor and with other advanced process analytical technology (PAT) sensors. Drying experiments were performed to demonstrate scalability to larger freeze dryers, including the determination of vial heat transfer coefficients, K v . Product temperature histories during K v runs were evaluated and compared with those obtained with a commercial laboratory-scale freeze dryer (LyoStar II) for sucrose and mannitol product formulations. When the mini-FD wall temperature was set at the LyoStar II band temperature (- 20°C) to mimic lab dryer edge vials, edge vial drying in the mini-FD possessed an average K v within 5% of those obtained during drying in the LyoStar II. When the wall temperature of the mini-FD was set equal to the central vial product temperature, edge vials behaved as center vials, possessing a K v value within 5% of those measured in the LyoStar II. During both K v runs and complete product freeze drying runs, the temperature-time profiles for the average edge vials and central vial in the mini-FD agreed well with the average edge and average central vials of the LyoStar II.

  8. Optimization of a cryoprotective medium to increase the viability of freeze-dried Streptococcus thermophilus by response surface methodology

    Science.gov (United States)

    Streptococcus thermophilus normally exhibits different survival rates in different bacteria medium during freeze-drying. In this study, response surface methodology (RSM) was applied on the design of experiments for optimizing the cryoprotective medium. Results showed that the most significant facto...

  9. In Vitro Impact of Conditioned Medium From Demineralized Freeze-Dried Bone on Human Umbilical Endothelial Cells.

    Science.gov (United States)

    Harnik, Branko; Miron, Richard J; Buser, Daniel; Gruber, Reinhard

    2017-03-01

    Angiogenesis is essential for the consolidation of bone allografts. The underlying molecular mechanism, however, remains unclear. Soluble factors released from demineralized freeze-dried bone target mesenchymal cells; however, their effect on endothelial cells has not been investigated so far. The aim of the present study was therefore to examine the effect of conditioned medium from demineralized freeze-dried bone on human umbilical endothelial cells in vitro. Conditioned medium was first prepared from demineralized freeze-dried bone following 24 hours incubation at room temperature to produce demineralized bone conditioned media. Thereafter, conditioned medium was used to stimulate human umbilical vein endothelial cells in vitro by determining the cell response based on viability, proliferation, expression of apoptotic genes, a Boyden chamber to determine cell migration, and the formation of branches. The authors report here that conditioned medium decreased viability and proliferation of endothelial cells. Neither of the apoptotic marker genes was significantly altered when endothelial cells were exposed to conditioned medium. The Boyden chamber revealed that endothelial cells migrate toward conditioned medium. Moreover, conditioned medium moderately stimulated the formation of branches. These findings support the concept that conditioned medium from demineralized freeze-dried bone targets endothelial cells by decreasing their proliferation and enhancing their motility under these in vitro conditions.

  10. Freeze-dried stallion spermatozoa: evaluation of two chelating agents and comparative analysis of three sperm DNA damage assays.

    Science.gov (United States)

    Olaciregui, M; Luño, V; Martí, J I; Aramayona, J; Gil, L

    2016-11-01

    During the freeze-drying procedure, sperm DNA might become damaged by both freezing and drying stresses. Sperm DNA status can be detected using well-established assays; however, most techniques are expensive and involve elaborate protocols and equipment. Indirect assessments can provide alternative strategies. The objective of this study was to compare a simple test of DNA status using Diff-Quik (DQ) with two established procedures: acridine orange test (AOT) and sperm chromatin dispersion (SCD) on freeze-dried (FD) stallion spermatozoa. Ejaculated spermatozoa from three stallions were freeze-dried in basic medium supplemented with two different chelating agents: EGTA or EDTA. After rehydration, the spermatozoa were subjected to DNA damage detection using a SCDt, AOT and DQ stain simultaneously. The results showed that the DNA damage levels in the EGTA group were significantly lower than those in the EDTA group. AOT detected a significantly higher proportion of spermatozoa with fragmented DNA than DQ and SCD. The results of the SCD test and DQ stain exhibited a significant positive correlation for DNA fragmentation (r = 0.528), whereas a negative correlation was observed between SCD, DQ and AOT (r = -0.134 and r = -0.332 respectively). The present study shows that both the SCD test and DQ assay are effective methods for detecting FD stallion sperm DNA fragmentation, whereas using of AOT is questionable.

  11. Evaluation of 3D-Printed Polycaprolactone Scaffolds Coated with Freeze-Dried Platelet-Rich Plasma for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Junda Li

    2017-07-01

    Full Text Available Three-dimensional printing is one of the most promising techniques for the manufacturing of scaffolds for bone tissue engineering. However, a pure scaffold is limited by its biological properties. Platelet-rich plasma (PRP has been shown to have the potential to improve the osteogenic effect. In this study, we improved the biological properties of scaffolds by coating 3D-printed polycaprolactone (PCL scaffolds with freeze-dried and traditionally prepared PRP, and we evaluated these scaffolds through in vitro and in vivo experiments. In vitro, we evaluated the interaction between dental pulp stem cells (DPSCs and the scaffolds by measuring cell proliferation, alkaline phosphatase (ALP activity, and osteogenic differentiation. The results showed that freeze-dried PRP significantly enhanced ALP activity and the mRNA expression levels of osteogenic genes (ALP, RUNX2 (runt-related gene-2, OCN (osteocalcin, OPN (osteopontin of DPSCs (p < 0.05. In vivo, 5 mm calvarial defects were created, and the PRP-PCL scaffolds were implanted. The data showed that compared with traditional PRP-PCL scaffolds or bare PCL scaffolds, the freeze-dried PRP-PCL scaffolds induced significantly greater bone formation (p < 0.05. All these data suggest that coating 3D-printed PCL scaffolds with freeze-dried PRP can promote greater osteogenic differentiation of DPSCs and induce more bone formation, which may have great potential in future clinical applications.

  12. Freeze-drying for controlled nanoparticle distribution in Co/SiO 2 Fischer–Tropsch catalysts

    NARCIS (Netherlands)

    Eggenhuisen, T.M.; Munnik, P.; Talsma, H.; de Jongh, P.E.; de Jong, K.P.

    2013-01-01

    Controlling the nanoparticle distribution over a support is considered essential to arrive at more stable catalysts. By developing a novel freeze drying method, the nanoparticle distribution was successfully manipulated for the preparation of Co/SiO2 Fischer-Tropsch catalysts using a commercial sili

  13. IR STUDY ON MONOMOLECULAR PARTICLE AGGLOMERATES OF POLYSTYRENE OBTAINED BY FREEZE-DRYING OF ITS DILUTE SOLUTION

    Institute of Scientific and Technical Information of China (English)

    Song Wang; Qing-hua Wang; Rong-shi Cheng

    2002-01-01

    The monomolecular particle agglomerates of polystyrenes were obtained by freeze-drying of its very dilutesolutions of 1.3 x 10-5-2.0 x 10-s g/mL in benzene:cylcohexane (100:1) solvents, and they were annealed at roomtemperature for hundred days before use. According to 13C-NMR measurement the polystyrenes should be practically atactic.The number average molecular weights of the samples are 2.80 x 103, 2.00 x 104, and 1.55 x 106, respectively. The freeze-dried aPS with a molecular weight higher than 104 show two new IR absorption bands at 1098 and 1261 cm-1, which areabsent in the normal aPS and freeze-dried styrene oligomer. it was also found that the low molecular weight samples canonly form powders, whereas the freeze-dried aPS with higher molecular weight form a mixture of powders and fibrils, ofwhich the longer fibrils show a much stronger 1261 cm-1 band than the shorter fibrils and the powder. It seems that the1261 cm-1 band corresponds to the stacking behavior of monomolecular particles.

  14. Research Article: Effects of long-term simulated Martian conditions on a freeze-dried and homogenized bacterial permafrost community

    DEFF Research Database (Denmark)

    Hansen, Aviaja Anna; Jensen, Lars Liengård; Kristoffersen, Tommy

    2009-01-01

    Indigenous bacteria and biomolecules (DNA and proteins) in a freeze-dried and homogenized Arctic permafrost were exposed to simulated martian conditions that correspond to about 80 days on the surface of Mars with respect to the accumulated UV dose. The simulation conditions included UV radiation...... and polynucleotides are more resistant to destruction than living biota. Astrobiology 9, 229-240....

  15. In-line near infrared spectroscopy during freeze-drying as a tool to measure efficiency of hydrogen bond formation between protein and sugar, predictive of protein storage stability

    NARCIS (Netherlands)

    Mensink, Maarten A; Van Bockstal, Pieter-Jan; Pieters, Sigrid; De Meyer, Laurens; Frijlink, Henderik W; van der Voort Maarschalk, Kees; Hinrichs, Wouter L J; De Beer, Thomas

    2015-01-01

    Sugars are often used as stabilizers of protein formulations during freeze-drying. However, not all sugars are equally suitable for this purpose. Using in-line near-infrared spectroscopy during freeze-drying, it is shown here that hydrogen bond formation during freeze-drying, under secondary drying

  16. First steps towards tissue engineering of small-diameter blood vessels: preparation of flat scaffolds of collagen and elastin by means of freeze drying

    NARCIS (Netherlands)

    Buttafoco, L.; Engbers-Buijtenhuijs, P.; Poot, Andreas A.; Dijkstra, Pieter J.; Daamen, W.F.; van Kuppevelt, T.H.; Vermes, I.; Feijen, Jan

    2006-01-01

    Porous scaffolds composed of collagen or collagen and elastin were prepared by freeze drying at temperatures between -18 and -196°C. All scaffolds had a porosity of 90-98% and a homogeneous distribution of pores. Freeze drying at -18°C afforded collagen and collagen/elastin matrices with average

  17. Gelatin-Filtered Consomme: A Practical Demonstration of the Freezing and Thawing Processes

    Science.gov (United States)

    Lahne, Jacob B.; Schmidt, Shelly J.

    2010-01-01

    Freezing is a key food processing and preservation technique widely used in the food industry. Application of best freezing and storage practices extends the shelf-life of foods for several months, while retaining much of the original quality of the fresh food. During freezing, as well as its counterpart process, thawing, a number of critical…

  18. Impact of the industrial freezing process on selected vegetables -Part II. Colour and bioactive compounds

    NARCIS (Netherlands)

    Mazzeo, Teresa; Paciulli, Maria; Chiavaro, Emma; Visconti, Attilio; Fogliano, Vincenzo; Ganino, Tommaso; Pellegrini, Nicoletta

    2015-01-01

    In the present study, the impact of the different steps (i.e. blanching, freezing, storage following the industrial freezing process and the final cooking prior to consumption) of the industrial freezing process was evaluated on colour, chlorophylls, lutein, polyphenols and ascorbic acid content

  19. Impact of the industrial freezing process on selected vegetables -Part II. Colour and bioactive compounds

    NARCIS (Netherlands)

    Mazzeo, Teresa; Paciulli, Maria; Chiavaro, Emma; Visconti, Attilio; Fogliano, Vincenzo; Ganino, Tommaso; Pellegrini, Nicoletta

    2015-01-01

    In the present study, the impact of the different steps (i.e. blanching, freezing, storage following the industrial freezing process and the final cooking prior to consumption) of the industrial freezing process was evaluated on colour, chlorophylls, lutein, polyphenols and ascorbic acid content

  20. Uncertainty analysis as essential step in the establishment of the dynamic Design Space of primary drying during freeze-drying

    DEFF Research Database (Denmark)

    Mortier, Severine Therese F. C.; Van Bockstal, Pieter-Jan; Corver, Jos

    2016-01-01

    values for both process variables during processing, resulting in a dynamic Design Space with a well-known risk of failure. This allows running the primary drying process step as time efficient as possible, hereby guaranteeing that the temperature at the sublimation front does not exceed the collapse...... of the Design Space, although it is often neglected. To quantitatively assess the inherent uncertainty on the parameters of the mechanistic model, an uncertainty analysis was performed to establish the borders of the dynamic Design Space, i.e. a time-varying shelf temperature and chamber pressure, associated...... with a specific risk of failure. A risk of failure acceptance level of 0.01%, i.e. a 'zero-failure' situation, results in an increased primary drying process time compared to the deterministic dynamic Design Space; however, the risk of failure is under control. Experimental verification revealed that only a risk...

  1. Non-contact AFM investigation of influence of freezing process on the surface structure of potato starch granule

    Science.gov (United States)

    Krok, F.; Szymońska, J.; Tomasik, P.; Szymoński, M.

    2000-04-01

    To assess the influence of the freezing process on the surface structure of a potato starch granule, a non-contact Atomic Force Microscopy (NC-AFM) investigation at ambient conditions has been undertaken. The observations were carried out for dried (oven-dried) and native (air-dried) starch. The obtained AFM images of the native starch granule surface demonstrated it as not uniformly smooth and having rough undulating appearance with layers of adsorbed water which could be removed by oven drying in 130°C. After freezing, the dried starch granule surface still consisted of nodules of about 100 nm in diameter. Significant changes in the granule surface appearance can be seen for dried starch samples frozen with some excess of water as well as for native starch samples frozen with its original water. Then the aggregation and polishing of the granules was observed and their surface revealed a microstructure with distinct ring-like protrusions of about 300 nm in diameter. Our observations tally with the amylopectine "blocket" starch granule structure model proposed in the literature and allowed to conclude that freezing may be a useful tool, among other methods, for modifying starch granule properties.

  2. Vacuum freeze-drying progress of purple sweet potato leaves%真空冷冻干燥紫甘薯叶的工艺研究

    Institute of Scientific and Technical Information of China (English)

    孙莉; 蒲传奋; 姜文利; 张岩; 杜善词; 王世清

    2012-01-01

    为了对采后紫甘薯叶进行充分的开发利用,提高农副产品的附加值及利用率,研究了紫甘薯叶真空冷冻干燥的最佳工艺参数。以冻干后紫甘薯叶的含水量为指标,利用正交试验对冻干过程的3个阶段进行了分析。并以色差变化为指标,采用正交试验研究了紫甘薯叶的最佳护色条件。研究表明:紫甘薯叶真空冷冻干燥最佳工艺过程为:预冻3h,升华干燥8h,解析干燥2h;最佳护色条件为:护色剂ZnCI2、质量浓度500mg/L、温度70℃、时N30s。%The best parameters of purple sweet potato leaves were studied by using vacuum freeze-drying technology in this paper, the water content of the purple sweet potato leaves after the freeze-drying was as an indicator, the three stages of freeze-drying process were analyzed by orthogonal experiment; the color change was as an indicator, the best conditions of color protection was studied through orthogonal experiment. The results showed that: the best vacuum freeze-drying process of purple sweet potato leaves as follow: the pre-freeze time was 3 h, the sublimation drying time was 8 h, the analytical drying time was 2 h; the best conditions of color protection as follow: the color fixative was ZnCI2, the density was 500 mg/L, temperature was 70 %, time was 30 s.

  3. A comparison between spray drying and spray freeze drying for dry powder inhaler formulation of drug-loaded lipid-polymer hybrid nanoparticles.

    Science.gov (United States)

    Wang, Yajie; Kho, Katherine; Cheow, Wean Sin; Hadinoto, Kunn

    2012-03-15

    Lipid-polymer hybrid nanoparticles - polymeric nanoparticles enveloped by lipid layers - have emerged as a potent therapeutic nano-carrier alternative to liposomes and polymeric nanoparticles. Herein we perform comparative studies of employing spray drying (SD) and spray freeze drying (SFD) to produce inhalable dry-powder form of drug-loaded lipid-polymer hybrid nanoparticles. Poly(lactic-co-glycolic acid), lecithin, and levofloxacin are employed as the polymer, lipid, and drug models, respectively. The hybrid nanoparticles are transformed into micro-scale nanoparticle aggregates (or nano-aggregates) via SD and SFD, where the effects of (1) different excipients (i.e. mannitol, polyvinyl alcohol (PVA), and leucine), and (2) nanoparticle to excipient ratio on nano-aggregate characteristics (e.g. size, flowability, aqueous reconstitution, aerosolization efficiency) are examined. In both methods, PVA is found more effective than mannitol for aqueous reconstitution, whereas hydrophobic leucineis needed to achieve effective aerosolization as it reduces nano-aggregate agglomeration. Using PVA, both methods are equally capable of producing nano-aggregates having size, density, flowability, yield and reconstitutibility in the range ideal for inhaled delivery. Nevertheless, nano-aggregates produced by SFD are superior to SD in terms of their aerosolization efficiency manifested in the higher emitted dose and fine particle fraction with lower mass median aerodynamic diameter.

  4. Stability of buffer-free freeze-dried formulations: A feasibility study of a monoclonal antibody at high protein concentrations.

    Science.gov (United States)

    Garidel, Patrick; Pevestorf, Benjamin; Bahrenburg, Sven

    2015-11-01

    We studied the stability of freeze-dried therapeutic protein formulations over a range of initial concentrations (from 40 to 160 mg/mL) and employed a variety of formulation strategies (including buffer-free freeze dried formulations, or BF-FDF). Highly concentrated, buffer-free liquid formulations of therapeutic monoclonal antibodies (mAbs) have been shown to be a viable alternative to conventionally buffered preparations. We considered whether it is feasible to use the buffer-free strategy in freeze-dried formulations, as an answer to some of the known drawbacks of conventional buffers. We therefore conducted an accelerated stability study (24 weeks at 40 °C) to assess the feasibility of stabilizing freeze-dried formulations without "classical" buffer components. Factors monitored included pH stability, protein integrity, and protein aggregation. Because the protein solutions are inherently self-buffering, and the system's buffer capacity scales with protein concentration, we included highly concentrated buffer-free freeze-dried formulations in the study. The tested formulations ranged from "fully formulated" (containing both conventional buffer and disaccharide stabilizers) to "buffer-free" (including formulations with only disaccharide lyoprotectant stabilizers) to "excipient-free" (with neither added buffers nor stabilizers). We evaluated the impacts of varying concentrations, buffering schemes, pHs, and lyoprotectant additives. At the end of 24 weeks, no change in pH was observed in any of the buffer-free formulations. Unbuffered formulations were found to have shorter reconstitution times and lower opalescence than buffered formulations. Protein stability was assessed by visual inspection, sub-visible particle analysis, protein monomer content, charge variants analysis, and hydrophobic interaction chromatography. All of these measures found the stability of buffer-free formulations that included a disaccharide stabilizer comparable to buffer

  5. Spray-freeze-drying of nanosuspensions: the manufacture of insulin particles for needle-free ballistic powder delivery

    Science.gov (United States)

    Schiffter, Heiko; Condliffe, Jamie; Vonhoff, Sebastian

    2010-01-01

    The feasibility of preparing microparticles with high insulin loading suitable for needle-free ballistic drug delivery by spray-freeze-drying (SFD) was examined in this study. The aim was to manufacture dense, robust particles with a diameter of around 50 µm, a narrow size distribution and a high content of insulin. Atomization using ultrasound atomizers showed improved handling of small liquid quantities as well as narrower droplet size distributions over conventional two-fluid nozzle atomization. Insulin nanoparticles were produced by SFD from solutions with a low solid content (300 mg ml−1) consisting of trehalose, mannitol, dextran (10 kDa) and dextran (150 kDa) (abbreviated to TMDD) in order to maximize particle robustness and density after SFD. With the increase in insulin content, the viscosity of the nanosuspensions increased. Liquid atomization was possible up to a maximum of 250 mg of nano-insulin suspended in a 1.0 g matrix. However, if a narrow size distribution with a good correlation between theoretical and measurable insulin content was desired, no more than 150 mg nano-insulin could be suspended per gram of matrix formulation. Particles were examined by laser light diffraction, scanning electron microscopy and tap density testing. Insulin stability was assessed using size exclusion chromatography (SEC), reverse phase chromatography and Fourier transform infrared (FTIR) spectroscopy. Densification of the particles could be achieved during primary drying if the product temperature (Tprod) exceeded the glass transition temperature of the freeze concentrate (Tg′) of −29.4°C for TMDD (3∶3∶3∶1) formulations. Particles showed a collapsed and wrinkled morphology owing to viscous flow of the freeze concentrate. With increasing insulin loading, the d (v, 0.5) of the SFD powders increased and particle size distributions got wider. Insulin showed a good stability during the particle formation process with a maximum decrease in insulin monomer of

  6. Sterilization of freeze dried manila clam (Ruditapea philippinarum) porridge for immuno-compromised patients

    Energy Technology Data Exchange (ETDEWEB)

    Song, Beom Seok; Park, Jae Nam [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2017-02-15

    This study was conducted to evaluate the combined effect of gamma irradiation and different conditions (vacuum packaging, antioxidant and freezing) on the microbiological and sensory characteristics of freeze dried Manila clam porridge (MCP) for immuno-compromised patient food. McP can be sterilized at 1 kGy to 10 kGy. the initial counts of total aerobic bacteria and yeast molds in the non-irradiated MCP were 2.4±0.5 and 1.2±0.3 log CFU g{sup -}'1, respectively, but gamma irradiation significantly decreased the total aerobic bacteria to below the detection limit (1 log CFU g{sup -1}) (5 kGy). Moreover, gamma irradiation effectively eliminated yeasts/molds at dose below than 1 kGy. However, gamma irradiation accelerated the increase of lipid oxidation and therefore, decreased the sensory characteristics of MCP as irradiation dose increased. to improve the sensory qualities of gamma irradiated MCP, combination treatment (vacuum packaging, 0.1% vitamin c) were applied. there was no significant difference in the overall acceptance scores between the combined-treatment sample (5.6 points) and the non-irradiated samples (6.0). the results indicate that combination treatment (vacuum packaging, 0.1% vitamin c) may help to maintain the quality of MCP. therefore, it considered that irradiation of MCP with combined treatment and this is an effective method for the consumption as a special purpose food such as for space travel or immuno-compromised patients.

  7. Thermal, Structural and Morphological Characterisation of Freeze-dried Copper(II Acetate Monohydrate and its Solid Decomposition Products

    Directory of Open Access Journals (Sweden)

    Bellini J.V.

    2002-01-01

    Full Text Available In the present study the thermal decomposition of a freeze-dried copper(II acetate monohydrate powder, (CH3COO2Cu.H2O, (FDCuAcH2O, was analysed by a combination of high-temperature X-ray diffractometry; differential scanning calorimetry and thermogravimetry, up to 700 degreesC. The structure and morphology of the calcined freeze-dried powders were analysed by scanning electron microscopy and X-ray diffractometry. The results showed that FDAcCuH2O decomposes during heating in two stages: I (25-225 degreesC FDCuAcH2O dehydrates giving rise to copper(II acetate, (CH3COO2Cu, (AcCu, and II (225-525 degreesC AcCu decomposes to CuO through complex oxidation reactions of Cu and Cu2O, simultaneously. SEM showed that FDCuAcH2O powder has a scale-like morphology, which is created in the freezing stage and retained after freeze-drying. After calcination at 125 and 225 degreesC, clusters of elongated tubes (or filaments compose the resulting powder (AcCu. Subsequent calcination at temperatures above 325 degreesC resulted in hard clusters of spheroid-like CuO particles.

  8. Numerical Simulation on Freezing Process of Saturated Granlar Soil

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The relation between ice pressure and load as a criterion of segregated ice initiation is introduced into the rigid ice model to simulate frost heave in saturated and granular soil. The calculated results show that unfrozen water content, thermal conductivity and hydraulic conductivity change greatly in frozen fringe. In numerical simulations, the influence of load, hydraulic conductivity and property of soil containing water on the process of soil freezing are analyzed, and the simulation curves such as cumulative heave,the change of depth of frozen and the distributions of water content are similar to the observations reported elsewhere.

  9. Finite Element Method (FEM) Modeling of Freeze-drying: Monitoring Pharmaceutical Product Robustness During Lyophilization.

    Science.gov (United States)

    Chen, Xiaodong; Sadineni, Vikram; Maity, Mita; Quan, Yong; Enterline, Matthew; Mantri, Rao V

    2015-12-01

    Lyophilization is an approach commonly undertaken to formulate drugs that are unstable to be commercialized as ready to use (RTU) solutions. One of the important aspects of commercializing a lyophilized product is to transfer the process parameters that are developed in lab scale lyophilizer to commercial scale without a loss in product quality. This process is often accomplished by costly engineering runs or through an iterative process at the commercial scale. Here, we are highlighting a combination of computational and experimental approach to predict commercial process parameters for the primary drying phase of lyophilization. Heat and mass transfer coefficients are determined experimentally either by manometric temperature measurement (MTM) or sublimation tests and used as inputs for the finite element model (FEM)-based software called PASSAGE, which computes various primary drying parameters such as primary drying time and product temperature. The heat and mass transfer coefficients will vary at different lyophilization scales; hence, we present an approach to use appropriate factors while scaling-up from lab scale to commercial scale. As a result, one can predict commercial scale primary drying time based on these parameters. Additionally, the model-based approach presented in this study provides a process to monitor pharmaceutical product robustness and accidental process deviations during Lyophilization to support commercial supply chain continuity. The approach presented here provides a robust lyophilization scale-up strategy; and because of the simple and minimalistic approach, it will also be less capital intensive path with minimal use of expensive drug substance/active material.

  10. 双孢菇微波冷冻干燥特性及干燥品质%Drying characteristics and quality of button mushrooms during microwave freeze drying

    Institute of Scientific and Technical Information of China (English)

    段续; 刘文超; 任广跃; 庞玉琪; 刘云宏

    2016-01-01

    Button mushroom is the most widely cultivated and consumed mushroom throughout the world and it contributes about 40% of the total world production of mushroom. Button mushrooms are extremely perishable and their shelf life is only about 24 h in ambient conditions. Various physiological and morphological changes occur after harvest, which make these mushrooms unacceptable for consumption. Hence, they should be consumed or processed promptly after harvest and for this reason the mushrooms are traded mostly in dried form in the world market. The convective drying method is the most commonly used to dry mushrooms. Nevertheless, due to long drying time and high drying temperature at industrial scale, the problems of darkening in color, shrinkage, loss in flavor and decrease in rehydration ability easily occur. In recent years, microwave freeze drying (MFD) has been investigated as a potential method for obtaining high quality dried food products with low energy consumption. Thus, to achieve faster drying rate with high product quality, MFD was applied to dry button mushrooms. The drying curves, effective moisture diffusivity, rehydration ratio, shrinkage ratio, vitamin C retention ratio, energy consumption and the sensory evaluation based on the fuzzy reasoning were investigated, which were considered to reflect the drying and quality characteristics of button mushrooms under different microwave loading levels (0.25, 1.0 and 0.75 W/g) and system pressure (50, 100 and 150 Pa). The drying models were obtained by the nonlinear fitting of drying curves. The weighted comprehensive evaluation of button mushroom MFD processes were also carried out based on energy consumption, drying time, rehydration ratio, whiteness index and vitamin C retention ratio. Results showed that, when changing the microwave loading level, the reduction ratio of the minimum value to the maximum value of drying time, effective moisture diffusion coefficient, whiteness index, rehydration ratio and

  11. Improvement of a dry formulation of Pseudomonas fluorescens EPS62e for fire blight disease biocontrol by combination of culture osmoadaptation with a freeze-drying lyoprotectant.

    Science.gov (United States)

    Cabrefiga, J; Francés, J; Montesinos, E; Bonaterra, A

    2014-10-01

    To study the effect of lyoprotectants and osmoadaptation on viability of Pseudomonas fluorescens EPS62e during freeze-drying and storage and to evaluate the formulation in terms of efficacy in biocontrol and fitness on pear flowers. A wettable powder formulation of a biocontrol agent of fire blight was optimized by means of lyoprotectants and culture osmoadaptation. Freeze-drying was used to obtain dehydrated cells, and the best viability (70% of survival) was obtained using lactose as lyoprotectant. Survival during lyophilization was additionally improved using physiological adaptation of cells during cultivation under salt-amended medium (osmoadaptation). The procedure increased the survival of cells after freeze-drying attaining viability values close to a 100% in the lactose-formulated product (3 × 10(11) CFU g(-1) ), and through the storage period of 1 year at 4°C. The dry formulation showed also an improved biocontrol efficacy and survival of EPS62e on pear flowers under low relative humidity conditions. Cell viability after freeze-drying was improved using lactose as lyoprotectant combined with a procedure of osmoadaptation during cultivation. The powder-formulated product remained active for 12 months and retained biocontrol levels similar to that of fresh cells. The formulation showed an improved survival of EPS62e on flowers and an increase of the efficacy of biocontrol of fire blight at low relative humidity. The results have a potential value for commercial application in biocontrol agents not only of fire blight but also of other plant diseases. © 2014 The Society for Applied Microbiology.

  12. High-intensity drying processes-impulse drying

    Energy Technology Data Exchange (ETDEWEB)

    Orloff, D.I.

    1991-06-01

    Impulse drying is an innovative process for drying paper that holds great promise for reducing the energy consumed during the manufacture of paper and similar web products. impulse drying occurs when a wet paper web passes through a press nip in which one of the rolls is heated to a high temperature. A steam layer adjacent to the heated surface grows and displaces water from the sheet in a very efficient manner. The energy required for water removal is very much less than that required for conventional evaporative drying. To eliminate sheet delamination, low thermal mass ceramic press roll coatings were developed to reduce heat transfer to the sheet, while maintaining high heat flux during early stages of the process. In so doing, most of the transferred energy is used to form steam that displaces liquid water, rather than in excessively heating the sheet. During this period, a prototype ceramic coating was developed and its impulse drying performance was compared to that of steel surfaces. It was observed that ceramic platens can be operated at higher temperatures and pressures resulting in improved water removal and physical properties without inducing sheet delamination. Heat flux measurement techniques were developed to provide a mechanistic explanation for the superior performance of the prototype. The work confirmed that the prototype ceramic coating is more energy efficient than the steel surface.

  13. High-intensity drying processes-impulse drying. Yearly report

    Energy Technology Data Exchange (ETDEWEB)

    Orloff, D.I.

    1991-06-01

    Impulse drying is an innovative process for drying paper that holds great promise for reducing the energy consumed during the manufacture of paper and similar web products. impulse drying occurs when a wet paper web passes through a press nip in which one of the rolls is heated to a high temperature. A steam layer adjacent to the heated surface grows and displaces water from the sheet in a very efficient manner. The energy required for water removal is very much less than that required for conventional evaporative drying. To eliminate sheet delamination, low thermal mass ceramic press roll coatings were developed to reduce heat transfer to the sheet, while maintaining high heat flux during early stages of the process. In so doing, most of the transferred energy is used to form steam that displaces liquid water, rather than in excessively heating the sheet. During this period, a prototype ceramic coating was developed and its impulse drying performance was compared to that of steel surfaces. It was observed that ceramic platens can be operated at higher temperatures and pressures resulting in improved water removal and physical properties without inducing sheet delamination. Heat flux measurement techniques were developed to provide a mechanistic explanation for the superior performance of the prototype. The work confirmed that the prototype ceramic coating is more energy efficient than the steel surface.

  14. Effect of microencapsulation methods on the survival of freeze-dried Bifidobacterium bifidum.

    Science.gov (United States)

    Zhang, Fan; Li, Xiao Yan; Park, Hyun Jin; Zhao, Min

    2013-01-01

    Six kinds of Bifidobacterium bifidum microcapsules were prepared by extrusion methods, emulsion methods and coacervation methods. Effects of preparation methods on the survival of encapsulated B. bifidum were examined. Results showed that microcapsules prepared by emulsion method with alginate and chitosan exhibited the best protection for B. bifidum. The diameter was 10-20 µm, encapsulation efficiency was 90.36% and the live cell amount was 3.01 × 10₉ cfu/g after freeze-drying. Encapsulated cells exhibited significantly higher resistance to artificial gastrointestinal juice and the cell numbers were above 10₉ cfu/g after exposure to simulated gastric (pH 1.2) and bile salt (1%, w/v). Cell numbers of microencapsulated B. bifidum was 8.61 × 10₈ cfu/g after storage at 37°C, relative humidity 60%-65% for 3 months. Results indicated microcapsules prepared with alginate and chitosan by emulsion method could successfully protect B. bifidum against adverse conditions and it might be useful in the delivery of probiotic cultures as a functional food.

  15. Multi-scale mechanical response of freeze-dried collagen scaffolds for tissue engineering applications.

    Science.gov (United States)

    Offeddu, Giovanni S; Ashworth, Jennifer C; Cameron, Ruth E; Oyen, Michelle L

    2015-02-01

    Tissue engineering has grown in the past two decades as a promising solution to unresolved clinical problems such as osteoarthritis. The mechanical response of tissue engineering scaffolds is one of the factors determining their use in applications such as cartilage and bone repair. The relationship between the structural and intrinsic mechanical properties of the scaffolds was the object of this study, with the ultimate aim of understanding the stiffness of the substrate that adhered cells experience, and its link to the bulk mechanical properties. Freeze-dried type I collagen porous scaffolds made with varying slurry concentrations and pore sizes were tested in a viscoelastic framework by macroindentation. Membranes made up of stacks of pore walls were indented using colloidal probe atomic force microscopy. It was found that the bulk scaffold mechanical response varied with collagen concentration in the slurry consistent with previous studies on these materials. Hydration of the scaffolds resulted in a more compliant response, yet lesser viscoelastic relaxation. Indentation of the membranes suggested that the material making up the pore walls remains unchanged between conditions, so that the stiffness of the scaffolds at the scale of seeded cells is unchanged; rather, it is suggested that thicker pore walls or more of these result in the increased moduli for the greater slurry concentration conditions.

  16. A novel collagen film with micro-rough surface structure for corneal epithelial repair fabricated by freeze drying technique

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 (China); Ren, Li, E-mail: psliren@scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 (China); Wang, Yingjun, E-mail: imwangyj@163.com [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 (China)

    2014-05-01

    Highlights: • Collagen film with micro-rough surface is fabricated by freeze drying technique. • The film has suitable water uptake capability and toughness performance. • The film has good optical performance. • Human corneal epithelial cells studies confirmed the biocompatibility of the film. - Abstract: Corneal epithelial defect is a common disease and keratoplasty is a common treatment method. A collagen film with micro-rough surface was fabricated through a simple freeze drying technique in this study. Compared with the air-dried collagen film (AD-Col), this freeze-dried collagen film (FD-Col) has a more suitable water uptake capability (about 85.5%) and toughness performance. Both of the two films have good optical properties and the luminousness of them is higher than 80%. Besides, the adhesion and proliferation rate of human corneal epithelial cells on the micro-rough surface of FD-Col film is higher than that on the smooth surface of AD-Col film. The results indicate that this FD-Col film may have potential applications for corneal epithelial repair.

  17. Extrusion processing : effects on dry canine diets

    NARCIS (Netherlands)

    Tran, Q.D.

    2008-01-01

    Keywords: Extrusion, Canine diet, Protein, Lysine, Starch gelatinization, Palatability, Drying. Extrusion cooking is a useful and economical tool for processing animal feed. This high temperature, short time processing technology causes chemical and physical changes that alter the nutritional and

  18. EUV extendibility via dry development rinse process

    Science.gov (United States)

    Sayan, Safak; Zheng, Tao; De Simone, Danilo; Vandenberghe, Geert

    2016-03-01

    Conventional photoresist processing involves resist coating, exposure, post-exposure bake, development, rinse and spin drying of a wafer. DDRP mitigates pattern collapse by applying a special polymer material (DDRM) which replaces the exposed/developed part of the photoresist material before wafer is spin dried. As noted above, the main mechanism of pattern collapse is the capillary forces governed by surface tension of rinse water and its asymmetrical recession from both sides of the lines during the drying step of the develop process. DDRP essentially eliminates these failure mechanisms by replacing remaining rinse water with DDRM and providing a structural framework that support resist lines from both sides during spin dry process. Dry development rinse process (DDRP) eliminates the root causes responsible for pattern collapse of photoresist line structures. Since these collapse mechanisms are mitigated, without the need for changes in the photoresist itself, achievable resolution of the state-of-the-art EUV photoresists can further be improved.

  19. Research on energy consumption in actual production of vacuum freeze-dried garlic slice%真空冷冻干燥蒜丁实际生产的能耗研究

    Institute of Scientific and Technical Information of China (English)

    刘业凤; 周国梁; 李续

    2014-01-01

    为了研究真空冷冻干燥蒜丁实际生产的能耗组成及节能措施,该文根据实地考察食品冷冻干燥厂蒜丁的真空冷冻干燥生产过程所得的资料,研究了冻干蒜丁实际生产过程的能耗,得到实际生产时单位脱水能耗为1.19 kW·h/kg,满足行业标准JB/T 10285-2001规定的冻干设备单位脱水量能耗不高于规定值即蒸汽加热单位脱水耗电量1.22 kW·h/kg的105%的要求。分析了生产过程中产品冻结、冻干过程中制冷系统、真空系统、加热系统、控制系统4大部分的能耗组成,从适当提高制冷系统蒸发温度及提高干燥仓压力等方面提出一些建议并达到了节能的目的,为以后食品冷冻干燥生产的节能设计提供一定参考。%Vacuum Freeze Drying has a great impact upon the production of dehydrated food because of the superior quality of the product obtained. Whereas, due to the slow rate of vacuum freeze drying, the long operation cycle, the high energy consumption generated by the vacuum freeze drying machine at run time, the development of freeze drying food will be restricted. In order to find energy-efficient approaches and seek lower cost productions, investigation was made on the process of freeze-dried garlic slice production in the freeze-dried food factory. In this paper, through analyzing the basic principle and drying process of vacuum freeze-dried garlic slice, energy consumption of refrigerating system, heating system and vacuum pump system was studied. By asking technicians and production manager from the factory, the main processing technology was learned. In addition, according to the experiences and field investigation, the technical date of lyophilized system including compressor, evaporator, condenser, ammonia pump, drying chamber and industrial boiler was learned as well as the stable parameter during the actual production process. Based on the obtained datum, using the principle of refrigeration

  20. Preservation of functionality of Bifidobacterium animalis subsp. lactis INL1 after incorporation of freeze-dried cells into different food matrices.

    Science.gov (United States)

    Vinderola, G; Zacarías, M F; Bockelmann, W; Neve, H; Reinheimer, J; Heller, K J

    2012-05-01

    The aim of this work was to investigate how production and freeze-drying conditions of Bifidobacterium animalis subsp. lactis INL1, a probiotic strain isolated from breast milk, affected its survival and resistance to simulated gastric digestion during storage in food matrices. The determination of the resistance of bifidobacteria to simulated gastric digestion was useful for unveiling differences in cell sensitivity to varying conditions during biomass production, freeze-drying and incorporation of the strain into food products. These findings show that bifidobacteria can become sensitive to technological variables (biomass production, freeze-drying and the food matrix) without this fact being evidenced by plate counts.

  1. FINAL REPORT: Transformational electrode drying process

    Energy Technology Data Exchange (ETDEWEB)

    Claus Daniel, C.; Wixom, M.(A123 Systems, Inc.)

    2013-12-19

    This report includes major findings and outlook from the transformational electrode drying project performance period from January 6, 2012 to August 1, 2012. Electrode drying before cell assembly is an operational bottleneck in battery manufacturing due to long drying times and batch processing. Water taken up during shipment and other manufacturing steps needs to be removed before final battery assembly. Conventional vacuum ovens are limited in drying speed due to a temperature threshold needed to avoid damaging polymer components in the composite electrode. Roll to roll operation and alternative treatments can increase the water desorption and removal rate without overheating and damaging other components in the composite electrode, thus considerably reducing drying time and energy use. The objective of this project was the development of an electrode drying procedure, and the demonstration of processes with no decrease in battery performance. The benchmark for all drying data was an 80°C vacuum furnace treatment with a residence time of 18 – 22 hours. This report demonstrates an alternative roll to roll drying process with a 500-fold improvement in drying time down to 2 minutes and consumption of only 30% of the energy compared to vacuum furnace treatment.

  2. Encapsulation and subsequent freeze-drying of Lactobacillus reuteri CRL 1324 for its potential inclusion in vaginal probiotic formulations.

    Science.gov (United States)

    Juárez Tomás, María Silvina; De Gregorio, Priscilla Romina; Leccese Terraf, María Cecilia; Nader-Macías, María Elena Fátima

    2015-11-15

    Probiotic formulations must include a high number of viable and active microorganisms. In this work, the survival of human vaginal Lactobacillus reuteri CRL 1324 during encapsulation, lyophilization and storage, and the activity of encapsulated and/or freeze-dried bacterial cells were evaluated. Extrusion-ionic gelation technique was applied to encapsulate L. reuteri CRL 1324, using xanthan and gellan. Encapsulated and free bacterial cells were freeze-dried with or without lactose and skim milk as lyoprotectors. The different systems obtained were stored at room temperature and at 4°C for 150days. The following determinations were performed: L. reuteri CRL 1324 viability, microorganism released from capsules, survival in a medium simulating the vaginal fluid and maintenance of beneficial properties (growth inhibition of opportunistic pathogenic Streptococcus agalactiae NH 17 and biofilm formation). L. reuteri CRL 1324 encapsulation was efficient, allowing the recovery of a high number of entrapped lactobacilli. The survival of encapsulated L. reuteri during lyophilization and storage was significantly higher in the presence of lyoprotectors. At the end of storage, the highest numbers of viable cells were obtained in free or encapsulated cells freeze-dried with lyoprotectors, stored at 4°C. Encapsulated and/or lyophilized L. reuteri cells maintained their viability in simulated vaginal fluid as well as the ability to inhibit S. agalactiae NH 17 growth and to form biofilm. Encapsulated and freeze-dried L. reuteri CRL 1324 can be included in a suitable pharmaceutical form for vaginal application to prevent or treat urogenital infections in women.

  3. Effect of chemical stabilizers on the thermostability and infectivity of a representative panel of freeze dried viruses.

    Directory of Open Access Journals (Sweden)

    Boris Pastorino

    Full Text Available As a partner of the European Virus Archive (EVA FP7 project, our laboratory maintains a large collection of freeze-dried viruses. The distribution of these viruses to academic researchers, public health organizations and industry is one major aim of the EVA consortium. It is known that lyophilization requires appropriate stabilizers to prevent inactivation of the virus. However, few studies have investigated the influence of different stabilizers and lyophilization protocols on the thermostability of different viruses. In order to identify optimal lyophilization conditions that will deliver maximum retention of viral infectivity titre, different stabilizer formulations containing trehalose, sorbitol, sucrose or foetal bovine serum were evaluated for their efficacy in stabilizing a representative panel of freeze dried viruses at different storage temperatures (-20°C, +4°C and +20°C for one week, the two latter mimicking suboptimal shipping conditions. The Tissue Culture Infectious Dose 50% (TCID50 assay was used to compare the titres of infectious virus. The results obtained using four relevant and model viruses (enveloped/non enveloped RNA/DNA viruses still serve to improve the freeze drying conditions needed for the development and the distribution of a large virus collection.

  4. Solidification of liposomes by freeze-drying: the importance of incorporating gelatin as interior support on enhanced physical stability.

    Science.gov (United States)

    Guan, Peipei; Lu, Yi; Qi, Jianping; Niu, Mengmeng; Lian, Ruyue; Wu, Wei

    2015-01-30

    The main purpose of this study was to investigate the effect of gelatin as interior support on the physical stability of freeze-dried liposomes. Anticancer agent paclitaxel (PTX) was selected as a model drug. Freeze-dried liposomes containing interior gelatin support (GLs) were prepared by thin-film dispersion/freeze-drying method. Several properties of the GLs, including entrapment efficiency, particle size and gelation temperature, were extensively characterized. Encapsulation efficiency of conventional liposomes (CLs) and liposomes containing lyoprotectants as interior support dropped to lower than 20% after reconstitution, while GLs still maintained an entrapment efficiency of over 84%. Scanning electron microscopy revealed well preserved liposomal structure of GLs after reconstitution. Meanwhile, the particle size and entrapment efficiency of GLs were also well preserved after reconstitution. In contrary, deformation of CLs and recrystallization of PTX were observed, as well as significant changes in particle size and entrapment efficiency. Taken together, interior gelatin support obviously enhanced the physical stability of liposomes against the lyophilization stress.

  5. Effect of freezing, hot tumble drying and washing with eucalyptus oil on house dust mites in soft toys.

    Science.gov (United States)

    Chang, Chin-Fu; Wu, Francis Fu-Sheng; Chen, Chi-Ying; Crane, Julian; Siebers, Rob

    2011-09-01

    Soft toys are a major source of house dust mites (HDM) and HDM allergens, and sleeping with soft toys is a significant risk factor for HDM sensitization. We studied three techniques to eliminate HDM from soft toys, namely freezing, hot tumble drying and washing with eucalyptus oil. Thirty-six toys (12 in each treatment group) were enumerated for live HDM by the heat escape method before and after freezing overnight, hot tumble drying for 1 h and washing in 0.2% to 0.4% eucalyptus oil. Freezing, hot tumble drying and washing with eucalyptus oil resulted in significant reductions in live HDM, an average reduction of 95.1%, 89.1% and 95.1%, respectively. Additionally, washing with eucalyptus oil resulted in a significant reduction in HDM allergens as well from a geometric mean of 9.12 μg/g to 0.37 μg/g (p = 0.033). These three HDM elimination techniques give parents of infants effective and acceptable methods of limiting HDM exposure.

  6. Optimisation of freeze drying conditions for purified serine protease from mango (Mangifera indicaCv. Chokanan) peel.

    Science.gov (United States)

    Mehrnoush, Amid; Tan, Chin Ping; Hamed, Mirhosseini; Aziz, Norashikin Ab; Ling, Tau Chuan

    2011-09-01

    This study investigated the possible relationship between the encapsulation variables, namely serine protease content (9-50mg/ml, X1), Arabic gum (0.2-10%(w/w), X2), maltodextrin (2-5%(w/w), X3) and calcium chloride (1.3-5.5%(w/w), X4) on the enzymatic properties of encapsulated serine protease. The study demonstrated that Arabic gum, maltodextrin and calcium chloride, as coating agents, protected serine protease from activity loss during freeze-drying. The overall optimum region resulted in a suitable freeze drying condition with a yield of 92% for the encapsulated serine protease, were obtained using 29.5mg/ml serine protease content, 5.1%(w/w) Arabic gum, 3.5%(w/w) maltodextrin and 3.4%(w/w) calcium chloride. It was found that the interaction effect of Arabic gum and calcium chloride improved the serine protease activity, and Arabic gum was the most effective amongst the examined coating agents. Thus, Arabic gum should be considered as potential protection in freeze drying of serine protease.

  7. Freeze-drying as suitable method to achieve ready-to-use yeast biosensors for androgenic and estrogenic compounds.

    Science.gov (United States)

    Jarque, Sergio; Bittner, Michal; Hilscherová, Klára

    2016-04-01

    Recombinant yeast assays (RYAs) have been proved to be a suitable tool for the fast screening of compounds with endocrine disrupting activities. However, ready-to-use versions more accessible to less equipped laboratories and field studies are scarce and far from optimal throughputs. Here, we have applied freeze-drying technology to optimize RYA for the fast assessment of environmental compounds with estrogenic and androgenic potencies. The effects of different cryoprotectants, initial optical density and long-term storage were evaluated. The study included detailed characterization of sensitivity, robustness and reproducibility of the new ready-to-use versions, as well as comparison with the standard assays. Freeze-dried RYAs showed similar dose-responses curves to their homolog standard assays, with Lowest Observed Effect Concentration (LOEC) and Median effective Concentration (EC50) of 1 nM and 7.5 nM for testosterone, and 0.05 nM and 0.5 nM for 17β-estradiol, respectively. Freeze-dried cells stored at 4 °C retained maximum sensitivity up to 2 months, while cells stored at -18 °C showed no decrease in sensitivity throughout the study (10 months). This ready-to-use RYA is easily accessible and may be potentially used for on-site applications.

  8. Impact of freeze-drying, mixing and horizontal transport on water vapor in the upper troposphere and lower stratosphere (UTLS)

    Science.gov (United States)

    Poshyvailo, Liubov; Ploeger, Felix; Müller, Rolf; Tao, Mengchu; Konopka, Paul; Abdoulaye Diallo, Mohamadou; Grooß, Jens-Uwe; Günther, Gebhard; Riese, Martin

    2017-04-01

    Water vapor in the upper troposphere and lower stratosphere (UTLS) is a key player in the global radiation budget. Therefore, a realistic representation of the water vapor distribution in this region and the involved control processes is critical for climate models, but largely uncertain hitherto. It is known that the extremely low temperatures around the tropical tropopause cause the dominant factor controlling water vapor in the lower stratosphere. Here, we focus on additional processes, such as horizontal transport between tropics and extratropics, small-scale mixing, and freeze-drying. We assess the sensitivities of simulated water vapor in the UTLS from simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS). CLaMS is a Lagrangian transport model, with a parameterization of small-scale mixing (model diffusion) which is coupled to deformations in the large-scale flow. First, to assess the robustness of water vapor with respect to the meteorological datasets we examine CLaMS driven by ECMWF ERA-Interim and the Japanese 55-year reanalysis. Second, to investigate the effects of small-scale mixing we vary the parameterized mixing strength in the CLaMS model between the reference case with the mixing strength optimized to reproduce atmospheric trace gas observations and a purely advective simulation with parameterized mixing turned off. Also calculation of Lagrangian cold points gives further insight of the processes involved. Third, to assess the effects of horizontal transport between the tropics and extratropics we carry out sensitivity simulations with horizontal transport barriers along latitude circles at the equator, 15°N/S and 35°N/S. Finally, the impact of Antarctic dehydration is estimated from additional sensitivity simulations with switched off freeze-drying in the model at high latitudes of 50°N/S. Our results show that the uncertainty in the tropical tropopause temperatures between current reanalysis datasets causes significant

  9. Space and Industrial Brine Drying Technologies

    Science.gov (United States)

    Jones, Harry W.; Wisniewski, Richard S.; Flynn, Michael; Shaw, Hali

    2014-01-01

    This survey describes brine drying technologies that have been developed for use in space and industry. NASA has long considered developing a brine drying system for the International Space Station (ISS). Possible processes include conduction drying in many forms, spray drying, distillation, freezing and freeze drying, membrane filtration, and electrical processes. Commercial processes use similar technologies. Some proposed space systems combine several approaches. The current most promising candidates for use on the ISS use either conduction drying with membrane filtration or spray drying.

  10. Dynamic culture improves MSC adhesion on freeze-dried bone as a scaffold for bone engineering.

    Science.gov (United States)

    Gonçalves, Fabiany da Costa; Paz, Ana Helena da Rosa; Lora, Priscila Schmidt; Passos, Eduardo Pandolfi; Cirne-Lima, Elizabeth Obino

    2012-02-26

    To investigate the interaction between mesenchymal stem cells (MSCs) and bone grafts using two different cultivation methods: static and dynamic. MSCs were isolated from rat bone marrow. MSC culture was analyzed according to the morphology, cell differentiation potential, and surface molecular markers. Before cell culture, freeze-dried bone (FDB) was maintained in culture for 3 d in order to verify culture medium pH. MSCs were co-cultured with FDB using two different cultivation methods: static co-culture (two-dimensional) and dynamic co-culture (three-dimensional). After 24 h of cultivation by dynamic or static methods, histological analysis of Cell adhesion on FDB was performed. Cell viability was assessed by the Trypan Blue exclusion method on days 0, 3 and 6 after dynamic or static culture. Adherent cells were detached from FDB surface, stained with Trypan Blue, and quantified to determine whether the cells remained on the graft surface in prolonged non-dynamic culture. Statistical analyses were performed with SPSS and a P cultures. Rat MSCs were positive for CD44, CD90 and CD29 and negative for CD34, CD45 and CD11bc. FDBs were maintained in culture for 3 d and the results showed there was no significant variation in the culture medium pH with FDB compared to pure medium pH (P > 0.05). In histological analysis, there was a significant difference in the amount of adhered cells on FDB between the two cultivation methods (P culture method demonstrated greater adhesion on the bone surface than in static co-culture method. On day 0, the cell viability in the dynamic system was significantly higher than in the static system (P statistical difference in cell viability between days 0, 3 and 6 after dynamic culture (P culture, cell viability on day 6 was significantly lower than on day 3 and 0 (P culture provides a superior environment over static conditions.

  11. Extended release promethazine HCl using acrylic polymers by freeze-drying and spray-drying techniques: formulation considerations

    Directory of Open Access Journals (Sweden)

    Ruchi Tiwari

    2009-12-01

    Full Text Available The present study investigated a novel extended release system of promethazine hydrochloride (PHC with acrylic polymers Eudragit RL100 and Eudragit S100 in different weight ratios (1:1 and 1: 5, and in combination (0.5+1.5, using freeze-drying and spray-drying techniques. Solid dispersions were characterized by Fourier-transformed infrared spectroscopy (FT-IR, differential scanning calorimetry (DSC, Powder X-ray diffractometry (PXRD, Nuclear magnetic resonance (NMR, Scanning electron microscopy (SEM, as well as solubility and in vitro dissolution studies in 0.1 N HCl (pH 1.2, double-distilled water and phosphate buffer (pH 7.4. Adsorption tests from drug solution to solid polymers were also performed. A selected solid dispersion system was developed into capsule dosage form and evaluated for in vitro dissolution studies. The progressive disappearance of drug peaks in thermotropic profiles of spray-dried dispersions were related to increasing amount of polymers, while SEM studies suggested homogenous dispersion of drug in polymer. Eudragit RL100 had a greater adsorptive capacity than Eudragit S100, and thus its combination in (0.5+1.5 for S100 and RL 100 exhibited a higher dissolution rate with 97.14% drug release for twelve hours. Among different formulations, capsules prepared by combination of acrylic polymers using spray-drying (1:0.5 + 1.5 displayed extended release of drug for twelve hours with 96.87% release followed by zero order kinetics (r²= 0.9986.O presente trabalho compreendeu estudo de um novo sistema de liberação prolongada de cloridrato de prometazina (PHC com polímeros acrílicos Eudragit RL100 e Eudragit S100 em diferentes proporções em massa (1:1 e 1:5 e em combinação (0,5+1,5, utilizando técnicas de liofilização e de secagem por aspersão As dispersões sólidas foram caracterizadas por espectrofotometria no infravermelho por transformada de Fourier (FT-IR, calorimetria diferencial de varredura (DSC, difratometria

  12. Zone Freezing Study for Pyrochemical Process Waste Minimization

    Energy Technology Data Exchange (ETDEWEB)

    Ammon Williams

    2012-05-01

    Pyroprocessing technology is a non-aqueous separation process for treatment of used nuclear fuel. At the heart of pyroprocessing lies the electrorefiner, which electrochemically dissolves uranium from the used fuel at the anode and deposits it onto a cathode. During this operation, sodium, transuranics, and fission product chlorides accumulate in the electrolyte salt (LiCl-KCl). These contaminates change the characteristics of the salt overtime and as a result, large volumes of contaminated salt are being removed, reprocessed and stored as radioactive waste. To reduce the storage volumes and improve recycling process for cost minimization, a salt purification method called zone freezing has been proposed at Korea Atomic Energy Research Institute (KAERI). Zone freezing is melt crystallization process similar to the vertical Bridgeman method. In this process, the eutectic salt is slowly cooled axially from top to bottom. As solidification occurs, the fission products are rejected from the solid interface and forced into the liquid phase. The resulting product is a grown crystal with the bulk of the fission products near the bottom of the salt ingot, where they can be easily be sectioned and removed. Despite successful feasibility report from KAERI on this process, there were many unexplored parameters to help understanding and improving its operational routines. Thus, this becomes the main motivation of this proposed study. The majority of this work has been focused on the CsCl-LiCl-KCl ternary salt. CeCl3-LiCl-KCl was also investigated to check whether or not this process is feasible for the trivalent species—surrogate for rare-earths and transuranics. For the main part of the work, several parameters were varied, they are: (1) the retort advancement rate—1.8, 3.2, and 5.0 mm/hr, (2) the crucible lid configurations—lid versus no-lid, (3) the amount or size of mixture—50 and 400 g, (4) the composition of CsCl in the salt—1, 3, and 5 wt%, and (5) the

  13. Breads Fortified with Freeze-Dried Vegetables: Quality and Nutritional Attributes. Part 1: Breads Containing Oil as an Ingredient

    Directory of Open Access Journals (Sweden)

    Viren Ranawana

    2016-03-01

    Full Text Available There is increasing emphasis on reformulating processed foods to make them healthier. This study for the first time comprehensively investigated the effects of fortifying bread (containing oil as an ingredient with freeze-dried vegetables on its nutritional and physico-chemical attributes. Breads fortified with carrot, tomato, beetroot or broccoli were assessed for nutrition, antioxidant potential, storage life, shelf stability, textural changes and macronutrient oxidation. Furthermore, using an in vitro model the study for the first time examined the impact of vegetable addition on the oxidative stability of macronutrients during human gastro-intestinal digestion. As expected, adding vegetables improved the nutritional and antioxidant properties of bread. Beetroot and broccoli significantly improved bread storage life. None of the vegetables significantly affected bread textural changes during storage compared to the control. Lipid oxidation in fresh bread was significantly reduced by all four types of vegetables whilst protein oxidation was lowered by beetroot, carrot and broccoli. The vegetables demonstrated varying effects on macronutrient oxidation during gastro-intestinal digestion. Beetroot consistently showed positive effects suggesting its addition to bread could be particularly beneficial.

  14. Influence of Freeze-Drying and Oven-Drying Post Blanching on the Nutrient Composition of the Edible Insect Ruspolia differens

    Directory of Open Access Journals (Sweden)

    Forkwa Tengweh Fombong

    2017-09-01

    Full Text Available The longhorn grasshopper, Ruspolia differens (Serville, plays an important role as a food source across Sub-Saharan Africa, where it is consumed as a delicacy in both rural and urban areas. The effect of two drying methods (freeze-drying and oven-drying, employed after blanching, on the proximate, fatty acid and mineral composition of the two most common morphs was determined. Ruspolia differens grasshoppers were harvested in Uganda and Kenya from wild swarms during the rainy periods of November–December 2016. Based on cuticular coloration, we identified three morphs, green, brown and purple, which occurred at a ratio of 65:33:2, respectively. Results indicated that these insects have a high lipid content of 36%, as well as significant protein levels ranging between 33% and 46% dry matter. Oleic acid (44% and palmitic acid (28% were the two most abundant fatty acids; while the presence of arachidonic acid (0.6% and docosahexaenoic acid (0.21% suggests that Ruspolia differens is also a source of polyunsaturated fatty acids. The observed amino acid profile showed similar trends in all morphs, and all essential amino acids were present. Calcium (896–1035 mg/100 g, potassium (779–816 mg/100 g and phosphorus (652–685 mg/100 g were quite high among the minerals. The presence of the trace elements iron (217–220 mg/100 g, zinc (14.2–14.6 mg/100 g, manganese (7.4–8.3 mg/100 g and copper (1.66 mg/100 g suggests that inclusion of these grasshoppers in human diets may aid in combatting micronutrient deficiencies. Oven-drying Ruspolia differens delivered the same nutritional quality as freeze-drying. Hence, both drying approaches can be adequately used to formulate insect-based food products without noticeable nutritional changes.

  15. Influence of Freeze-Drying and Oven-Drying Post Blanching on the Nutrient Composition of the Edible Insect Ruspolia differens

    Science.gov (United States)

    Fombong, Forkwa Tengweh; Van Der Borght, Mik; Vanden Broeck, Jozef

    2017-01-01

    The longhorn grasshopper, Ruspolia differens (Serville), plays an important role as a food source across Sub-Saharan Africa, where it is consumed as a delicacy in both rural and urban areas. The effect of two drying methods (freeze-drying and oven-drying), employed after blanching, on the proximate, fatty acid and mineral composition of the two most common morphs was determined. Ruspolia differens grasshoppers were harvested in Uganda and Kenya from wild swarms during the rainy periods of November–December 2016. Based on cuticular coloration, we identified three morphs, green, brown and purple, which occurred at a ratio of 65:33:2, respectively. Results indicated that these insects have a high lipid content of 36%, as well as significant protein levels ranging between 33% and 46% dry matter. Oleic acid (44%) and palmitic acid (28%) were the two most abundant fatty acids; while the presence of arachidonic acid (0.6%) and docosahexaenoic acid (0.21%) suggests that Ruspolia differens is also a source of polyunsaturated fatty acids. The observed amino acid profile showed similar trends in all morphs, and all essential amino acids were present. Calcium (896–1035 mg/100 g), potassium (779–816 mg/100 g) and phosphorus (652–685 mg/100 g) were quite high among the minerals. The presence of the trace elements iron (217–220 mg/100 g), zinc (14.2–14.6 mg/100 g), manganese (7.4–8.3 mg/100 g) and copper (1.66 mg/100 g) suggests that inclusion of these grasshoppers in human diets may aid in combatting micronutrient deficiencies. Oven-drying Ruspolia differens delivered the same nutritional quality as freeze-drying. Hence, both drying approaches can be adequately used to formulate insect-based food products without noticeable nutritional changes. PMID:28926949

  16. Stability of Freeze-Dried Sera Stored at Different Temperatures for the Detection of Anti-Leishmania infantum Antibodies Using Direct Agglutination Test.

    Directory of Open Access Journals (Sweden)

    Zahra Kakooei

    2014-11-01

    Full Text Available This study aimed to evaluate freeze-dried sera as an alternative to non-freeze dried for detection of anti-Leishmania infantum antibodies over the course of 11 months using the direct agglutination test (DAT.Altogether, 60 serum samples (30 from humans and 30 from dogs were collected from various geographical locations in Iran. All the collected sera were pooled and each pooled serum sample contained 10 different sera. In the beginning, the human and dog pooled sera were categorized as positive (weak and strong and negative based on anti-L. infantum antibodies using the DAT. All the freeze-dried and non-freeze-dried sera were stored at -70°C, -20°C, 4°C, 22-28°C and 56°C for 11 months. The positive and negative human and dog pooled sera were separately tested using the DAT each month and the results were compared to non-freeze-dried sera kept under the same conditions.We found strong agreement (100% between the results obtained from freeze-dried human and dog in strong DAT positive sera kept at -70°C, -20°C, 4°C and 22-28°C during this study. The human and dog pooled sera stored at 56°C were corrupted after 2 weeks. The DAT results were highly reproducible using freeze-dried human pooled sera in the beginning and month 11 of this study (CV = 0.036.Freeze-dried human and dog strong DAT positive sera are highly stable under different temperature conditions, are easy to transport and are safe for use as positive and negative serum controls in laboratories.

  17. Effects of drying process on the physicochemical properties of nopal cladodes at different maturity stages.

    Science.gov (United States)

    Contreras-Padilla, Margarita; Gutiérrez-Cortez, Elsa; Valderrama-Bravo, María Del Carmen; Rojas-Molina, Isela; Espinosa-Arbeláez, Diego Germán; Suárez-Vargas, Raúl; Rodríguez-García, Mario Enrique

    2012-03-01

    Chemical proximate analysis was done in order to determine the changes of nutritional characteristics of nopal powders from three different maturity stages 50, 100, and 150 days and obtained by three different drying processes: freeze dried, forced air oven, and tunnel. Results indicate that nopal powder obtained by the process of freeze dried retains higher contents of protein, soluble fiber, and fat than the other two processes. Also, freeze dried process had less effect on color hue variable. No changes were observed in insoluble fiber content, chroma and lightness with the three different drying processes. Furthermore, the soluble fibers decreased with the age of nopal while insoluble fibers and ash content shows an opposite trend. In addition, the luminosity and hue values did not show differences among the maturity stages studied. The high content of dietary fibers of nopal pad powder could to be an interesting source of these important components for human diets and also could be used in food, cosmetics and pharmaceutical industry.

  18. Dry powder inhalers: physicochemical and aerosolization properties of several size-fractions of a promising alterative carrier, freeze-dried mannitol.

    Science.gov (United States)

    Kaialy, Waseem; Nokhodchi, Ali

    2015-02-20

    The purpose of this work was to evaluate the physicochemical and inhalation characteristics of different size fractions of a promising carrier, i.e., freeze-dried mannitol (FDM). FDM was prepared and sieved into four size fractions. FDMs were then characterized in terms of micromeritic, solid-state and bulk properties. Dry powder inhaler (DPI) formulations were prepared using salbutamol sulphate (SS) and then evaluated in terms of drug content homogeneity and in vitro aerosolization performance. The results showed that the crystalline state of mannitol was maintained following freeze-drying for all size fractions of FDM. All FDM particles showed elongated morphology and contained mixtures of α-, β- and δ-mannitol. In comparison to small FDM particles, FDMs with larger particle sizes demonstrated narrower size distributions, higher bulk and tap densities, lower porosities and better flowability. Regardless of particle size, all FDMs generated a significantly higher (2.2-2.9-fold increase) fine particle fraction (FPF, 37.5 ± 0.9%-48.6 ± 2.8%) of SS in comparison to commercial mannitol. The FPFs of SS were related to the shape descriptors of FDM particles; however, FPFs did not prove quantitative apparent relationships with either particle size or powder bulk descriptors. Large FDM particles were more favourable than smaller particles because they produced DPI formulations with better flowability, better drug content homogeneity, lower amounts of the drug depositing on the throat and contained lower fine-particle-mannitol. Optimized stable DPI formulations with superior physicochemical and pharmaceutical properties can be achieved using larger particles of freeze-dried mannitol (FDM). Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Effects of freezing rates and cryoprotectant on thermal expansion of articular cartilage during freezing process.

    Science.gov (United States)

    Xu, Y; Sun, H J; Lv, Y; Zou, J C; Lin, B L; Hua, T C

    2013-01-01

    The intact articular cartilage has not yet been successfully preserved at low temperature most likely due to the volume expansion from water to ice during freezing. The objective of this current study focuses on examining thermal expansion behavior of articular cartilage (AC) during freezing from 0 degree C to -100 degree C. Thermo Mechanical Analysis (TMA) was used to investigate the effects of different concentrations of dimethyl sulphoxide (DMSO) (0%, 10%, 30% and 60% v/v) and different freezing rates (1 C/min, 3 C/min and 5 C/min). The results showed that: (1) the inhomogeneous thermal expansion (or contraction) presents due to inhomogeneous water distributions in articular cartilage during freezing, which also may be the most likely reason that the matrix has been damaged in cryopreserved intact articular cartilage; (2) at the phase transition temperature range, the maximum thermal strain change value for 5C/min is approximately 1.45 times than that for 1 C/min, but the maximum thermal expansion coefficient of the later is about six times than that of the former; (3) the thermal expansion coefficient decreases with increasing cooling rate at the unfrozen temperature region, but some opposite results are obtained at the frozen temperature region; (4) the higher the DMSO concentration is, at the phase change temperature region, the smaller the thermal strain change as well as the maximum thermal expansion coefficient are, but DMSO concentration exhibits little effect on the thermal expansion coefficient at both unfrozen and frozen region. Once the DMSO concentration increasing enough, e.g. 60% v/v, the thermal strain decreases linearly and smoothly without any abrupt change due to little or no ice crystal forms (i.e. vitrification) in frozen articular cartilage. This study may improve our understanding of the thermal expansion (or contraction) behavior of cryopreserved articular cartilage and it may be useful for the future study on cryopreservation of intact

  20. Fabrication of highly porous keratin sponges by freeze-drying in the presence of calcium alginate beads

    Energy Technology Data Exchange (ETDEWEB)

    Hamasaki, Shinichi; Tachibana, Akira; Tada, Daisuke; Yamauchi, Kiyoshi [Department of Applied Chemistry and Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Tanabe, Toshizumi [Department of Applied Chemistry and Bioengineering, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan)], E-mail: tanabe@bioa.eng.osaka-cu.ac.jp

    2008-12-01

    Novel fabrication method of highly porous and flexible keratin sponges was developed by combining a particulate-leaching method and a freeze-drying method. Reduced keratin aqueous solution was mixed with dried calcium alginate beads and was lyophilized to give keratin/calcium alginate complex, which was subsequently treated with EDTA solution to leach out calcium alginate beads. The resultant keratin sponge was flexible enough to handle even in dried state because of its quite high porosity (98.9 {+-} 0.1%), which was brought about by the large and small pores formed by the elimination of calcium alginate beads and water. The sponge supported the attachment and the proliferation of mouse fibroblast cells. Thus, the keratin sponge given by the present fabrication method afforded one alternative as a cell scaffold for tissue engineering.

  1. Encapsulation of antioxidant phenolic compounds extracted from spent coffee grounds by freeze-drying and spray-drying using different coating materials.

    Science.gov (United States)

    Ballesteros, Lina F; Ramirez, Monica J; Orrego, Carlos E; Teixeira, José A; Mussatto, Solange I

    2017-12-15

    Freeze-drying and spray-drying techniques were evaluated for encapsulation of phenolic compounds (PC) extracted from spent coffee grounds. Additionally, the use of maltodextrin, gum arabic and a mixture of these components (ratio 1:1) as wall material to retain the PC and preserve their antioxidant activity was also assessed. The contents of PC and flavonoids (FLA), as well as the antioxidant activity of the encapsulated samples were determined in order to verify the efficiency of each studied condition. Additional analyses for characterization of the samples were also performed. Both the technique and the coating material greatly influenced the encapsulation of antioxidant PC. The best results were achieved when PC were encapsulated by freeze-drying using maltodextrin as wall material. Under these conditions, the amount of PC and FLA retained in the encapsulated sample corresponded to 62% and 73%, respectively, and 73-86% of the antioxidant activity present in the original extract was preserved. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Pore architecture and cell viability on freeze dried 3D recombinant human collagen-peptide (RHC)–chitosan scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing; Zhou, Aimei; Deng, Aipeng [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Yang, Yang [Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Gao, Lihu; Zhong, Zhaocai [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Yang, Shulin, E-mail: yshulin@njust.edu.cn [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2015-04-01

    Pore architecture of 3D scaffolds used in tissue engineering plays a critical role in the maintenance of cell survival, proliferation and further promotion of tissue regeneration. We investigated the pore size and structure, porosity, swelling as well as cell viability of a series of recombinant human collagen-peptide–chitosan (RHCC) scaffolds fabricated by lyophilization. In this paper, freezing regime containing a final temperature of freezing (T{sub f}) and cooling rates was applied to obtain scaffolds with pore size ranging from 100 μm to 120 μm. Other protocols of RHC/chitosan suspension concentration and ratio modification were studied to produce more homogenous and appropriate structural scaffolds. The mean pore size decreased along with the decline of T{sub f} at a slow cooling rate of 0.7 °C/min; a more rapid cooling rate under 5 °C/min resulted to a smaller pore size and more homogenous microstructure. High concentration could reduce pore size and lead to thick well of scaffold, while improved the ratio of RHC, lamellar and fiber structure coexisted with cellular pores. Human umbilical vein endothelial cells (HUVECs) were seeded on these manufactured scaffolds, the cell viability represented a negative correlation to the pore size. This study provides an alternative method to fabricate 3D RHC–chitosan scaffolds with appropriate pores for potential tissue engineering. - Highlights: • Fabrication of recombinant human collagen-chitosan scaffolds by freezing drying • Influence of freeze drying protocols on lyophilized scaffolds • Pore size, microstructure, porosity, swelling and cell viability were compared. • The optimized porous scaffold is suitable for cell (HUVEC) seeding.

  3. In-line near infrared spectroscopy during freeze-drying as a tool to measure efficiency of hydrogen bond formation between protein and sugar, predictive of protein storage stability

    OpenAIRE

    Mensink, Maarten A.; Van Bockstal, Pieter-Jan; Pieters, S; De Meyer, Laurens; Frijlink, Henderik W.; van der Voort Maarschalk, Kees; Hinrichs, Wouter L.J.; De Beer, Thomas

    2015-01-01

    Sugars are often used as stabilizers of protein formulations during freeze-drying. However, not all sugars are equally suitable for this purpose. Using in-line near-infrared spectroscopy during freeze-drying, it is shown here that hydrogen bond formation during freeze-drying, under secondary drying conditions in particular, can be related to the preservation of the functionality and structure of proteins during storage. The disaccharide trehalose was best capable of forming hydrogen bonds wit...

  4. 微波真空冷冻干燥对芒果干制品品质特性的影响%Effect of Microwave Vacuum Freeze Drying on the Quality of Dried Mango

    Institute of Scientific and Technical Information of China (English)

    姜唯唯; 刘刚; 张晓喻; 范辉建; 张宏

    2012-01-01

    为获得较优的芒果干燥方法,以复水性、感官为评价指标,比较微波真空冷冻干燥、热板真空冷冻干燥和热风干燥3种不同干燥方法对芒果干制品品质的影响。结果表明:真空冷冻干燥法的产品各项指标均优于热风干燥法。微波真空冷冻干燥的产品复水性最好,25℃与100℃最大复水比分别为3.363、3.674;其次为热板真空冷冻干燥,两温度条件下与微波真空冷冻干燥产品复水比相差较小;热风干燥产品复水性最差,分别为2.140、3.028。感官指标中色泽、香气和口味3方面均为:微波真空冷冻干燥〉热板真空冷冻干燥〉热风干燥。%In order to obtain a better drying method for mango products, the effects of microwave vacuum freeze drying, hot- plate vacuum freeze drying and hot air drying on the rehydration rate and sensory quality of dried mango were comparatively analyzed. The results indicated that vacuum freeze drying could provide better indices of dried products when compared with hot-air drying. Microwave vacuum freeze dried mango exhibited the best rehydration performance with rehydration rates of 3.363 and 3.674 at 25 ~C and 100 ~C, respectively, followed by hot-plate vacuum freeze dried mango with rehydration rates comparable to those of microwave vacuum freeze dried mango at 25 ℃ and 100 ℃; the worst rehydration properties were obtained when mango was dried by hot air drying with rehydration rates of 2.140 and 3.028 at 25 ~C and 100 ~C, respectively. Similarly, microwave vaccum freeze drying resulted in the best color, aroma and taste in dried mango, followed by hot-plate vacuum freeze drying; hot air dried mango showed the worst color, aroma and taste.

  5. Dehydration and thermal inactivation of Lactobacillus plantarum WCFS1: Comparing single droplet drying to spray and freeze drying

    NARCIS (Netherlands)

    Perdana, J.A.; Bereschenko, L.A.; Fox, M.B.; Kuperus, J.H.; Kleerebezem, M.; Boom, R.M.; Schutyser, M.A.I.

    2013-01-01

    We demonstrated that viability loss during single droplet drying can be explained by the sum of dehydration and thermal inactivation. For Lactobacillus plantarum WCFS1, dehydration inactivation predominantly occurred at drying temperatures below 45 °C and only depended on the moisture content. Above

  6. Damage Evaluation on Freeze-Thawing Process of Food by Using NMR

    Science.gov (United States)

    Andou, Hiroko; Fukuoka, Mika; Miyawaki, Osato; Suzuki, Toru

    Freeze-thawing process gives significant damages for food structure. Several new techniques have been attempted for quantitative evaluation of the damages. In this study, using NMR (nuclear magnetic resonance) with a stimulated echo method, restricted diffusion phenomena of water molecules was measured for damaged food (onion and tuna) tissues that were subjected to the repeat of freeze-thawing, Through experiments, water permeability of tissue membrane was calculated. The water permeability of fresh tissues for onion showed clearly restricted diffusion, but after freeze-thawing, it disappeared. On the other hand, the water permeability of fresh tuna tissue was small significantly, even though it was a little higher after freeze-thawing. After all, the damage level after freeze-thawing showed a significant difference between onion and tuna. These results support the view that plant tissue is very sensitive to freeze-thawing and that the water permeability of plant is much lower than that of animal.

  7. Effects of drying processes on starch-related physicochemical properties, bioactive components and antioxidant properties of yam flours.

    Science.gov (United States)

    Chen, Xuetao; Li, Xia; Mao, Xinhui; Huang, Hanhan; Wang, Tingting; Qu, Zhuo; Miao, Jing; Gao, Wenyuan

    2017-06-01

    The effects of five different drying processes, air drying (AD), sulphur fumigation drying (SFD), hot air drying (HAD), freeze drying (FD) and microwave drying (MWD) for yams in terms of starch-related properties and antioxidant activity were studied. From the results of scanning electron microscopy (SEM), polarized optical microscopy (POM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR), the MWD sample was found to contain gelatinized starch granules. The FD yam had more slow digestible (SDS) and resistant starches (RS) compared with those processed with other modern drying methods. The bioactive components and the reducing power of the dried yams, were lower than those of fresh yam. When five dried samples were compared by principal component analysis, the HAD and SFD samples were observed to have the highest comprehensive principal component values. Based on our results, HAD would be a better method for yam drying than the more traditional SFD. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Construction and Application of HACCP System for Freeze-dried Pleurotus eryngii%冻干杏鲍菇HACCP质量控制体系的建立与应用

    Institute of Scientific and Technical Information of China (English)

    惠俊爱; 刘念

    2012-01-01

    为确保冻干杏鲍菇产品质量稳定、可控,在科学制定冻干杏鲍菇加工工艺的基础上,通过对加工过程中各工艺环节在整个产品质量体系中的重要性和可能性危害进行分析,确定出四个关键控制点,并提出了与之相适应的预防措施.为提高冻干杏鲍菇产品的质量与食用安全性提供了重要保证,也为其它冻干食品的质量管理与控制提供了借鉴.%To ensure product quality, stability and controllability of freeze-dried Pleurotus eryngii, four critical control points were identified based on the importance and hazard analysis of freeze-drying processing technology of Pleurotus eryngii throughout the product quality system. Preventive measures for adaptation were suggested to improve the quality and safety of freeze-dried products of Pleurotus eryngii, and provide a reference for quality management and control of other freeze dried foods.

  9. Comparative study of subtalar arthrodesis after calcaneal frature malunion with autologous bone graft or freeze-dried xenograft.

    Science.gov (United States)

    Henning, Carlo; Poglia, Gabriel; Leie, Murilo Anderson; Galia, Carlos Roberto

    2015-12-01

    Calcaneal fracture malunion may evolve into arthrosis and severe foot deformities. The aim of this study was to identify differences in bony union following corrective subtalar arthrodesis with interposition of autologous tricortical bone graft or freeze-dried bovine xenograft. We prospectively evaluated 12 patients who underwent subtalar arthrodesis, six patients received autografts and 6 received freeze-dried bovine xenografts. After a mean followup of 58 weeks, the patients were clinical assessed using AOFAS scale and the visual analog scale (VAS) for pain and for final radiographic parameters measurement. Two blind raters evaluated the length of time required for solid union of the arthrodesis and graft integration by retrospective radiographic examination. In the autograft group, AOFAS score improved from a preoperative average of 37 to 64 points postoperatively (p = 0.02) and mean VAS score improved from 4.7 to 1.9 (p = 0.028). In the xenograft group, AOFAS score improved from 38 to 74 points (p = 0.02) and VAS from 5.5 to 2.7 (p = 0.046). Solid union was achieved in all cases in the autograft group at an average of 5.3 weeks and in five cases in the xenograft group at 8.8 weeks (p = 0.077). Graft integration occurred after an average of 10.7 weeks in the autograft group and 28.8 weeks in the xenograft group (p = 0.016). With the numbers available, no significant difference could be detected in the length of time required for solid union of subtalar arthrodesis between groups, although time to integration of freeze-dried bovine xenografts was statistically higher. Clinical and functional improvement was observed in both groups.

  10. Pilot-scale Production and Viability Analysis of Freeze-Dried Probiotic Bacteria Using Different Protective Agents

    Directory of Open Access Journals (Sweden)

    Alberto Cresci

    2010-03-01

    Full Text Available The functional food industry requires an improvement of probiotic strain stability during storage, especially when they are stored at room temperature. In this study, the viability of freeze-dried Lactobacillus rhamnosus IMC 501® and Lactobacillus paracasei IMC 502® using different protective agents (i.e., glycerine, mannitol, sorbitol, inulin, dextrin, Crystalean® was determined and compared with semi skimmed milk (SSM control. No significant differences were observed between the tested protectants and the control (SSM during storage at refrigerated conditions. During storage at room temperature, only glycerine was found to stabilize viability better than other tested substances.

  11. Effects of Freeze-dried Mulberry on Antioxidant Activities and Fermented Characteristics of Yogurt during Refrigerated Storage

    OpenAIRE

    2015-01-01

    This study investigated the effect of added freeze-dried mulberry fruit juice (FDMJ) (1, 3 and 5%) on the antioxidant activity and fermented characteristic of yogurt during refrigerated storage. A decrease in pH of yogurt and increase in acidity was observed during fermentation. The yogurts with FDMJ exhibited faster rate of pH reduction than control. Initial lactic acid bacteria count of yogurt was 6.49-6.94 Log CFU/g and increased above 9 Log CFU/g in control and 1% in FDMJ yogurt for 24 h....

  12. Design of freeze-dried Soluplus/polyvinyl alcohol-based film for the oral delivery of an insoluble drug for the pediatric use.

    Science.gov (United States)

    Shamma, Rehab; Elkasabgy, Nermeen

    2016-01-01

    Spironolactone (SL) is a poorly water-soluble drug. Being poorly soluble affects its dissolution rate which in turn affects its oral bioavailability. This work aimed to prepare freeze-dried SL-Soluplus/polyvinyl alcohol (PVA) oral thin film in an attempt to enhance the drug solubility on one hand and at the same time prepare a solid dosage form convenient for the pediatric use. SL-Soluplus/PVA films were prepared using polyethylene glycol 400 (PEG 400) as a plasticizer applying the solvent-casting technique. The prepared films were evaluated for their thickness, tensile strength, and in vitro dissolution studies. Box-Behnken design (17 runs) was applied to optimize the effects of the formulation variables on the film properties. The optimized film formulation was freeze-dried after casting so as to enhance the drug dissolution. Moreover, the optimized freeze-dried film was re-characterized in vitro and evaluated in vivo in human volunteers to investigate its palatability and satisfaction. The results showed that the optimized formulation composed of 10% polymer concentration containing Soluplus:PVA (0.33:0.66) and plasticized with 30% PEG 400 possessed the highest desirability value (0.836). Freeze-drying of the optimized formulation succeeded to improve SL in vitro dissolution due to the preparation of a more porous film compared to the non-freeze-dried one. In vivo evaluation of the optimized freeze-dried film showed high satisfaction among the participating volunteers concerning the ease of administration and sensation thereafter, where all the film specimens dissolved without the need for water and no film residues remained in the mouth following film dissolution. In conclusion, freeze-dried Soluplus®/PVA-based oral thin film proved to be a successful carrier for the oral delivery of insoluble drugs like SL for pediatrics.

  13. Effects of cryoprotectants on the viability and activity of freeze dried recombinant yeasts as novel oral drug delivery systems assessed by an artificial digestive system.

    Science.gov (United States)

    Blanquet, Stéphanie; Garrait, Ghislain; Beyssac, Erick; Perrier, Céline; Denis, Sylvain; Hébrard, Géraldine; Alric, Monique

    2005-09-01

    The aim of this study was to investigate, in a gastric-small intestinal system TIM-1, the effect of cryoprotectants on the survival of freeze-dried Saccharomyces cerevisiae expressing the heterologous P450 73A1 and their ability to convert trans-cinnamic acid into p-coumaric acid. Yeasts were lyophilized in suspensions of trehalose, maltose, lactose, or a milk proteins/trehalose mix. Freeze-dried or native yeasts and trans-cinnamic acid were introduced simultaneously into TIM-1 at the beginning of digestion. Yeast survival rate was evaluated by cell counting in the ileal effluents. P450 73A1 activity was followed by HPLC assay of p-coumaric acid. Freeze-dried yeasts showed high tolerance to digestive conditions. Nevertheless, their survival rate was lower than that of non-dried cells (around 80% whatever the protective agent vs. 96%). The ability of recombinant freeze-dried S. cerevisiae to perform a bioconversion reaction in the digestive tract was shown with all the protectants. The highest trans-cinnamic acid conversion rate (24 vs. 41% for native yeasts) was obtained with the milk proteins/trehalose mix. These results show that freeze-drying might be considered for the pharmaceutical formulation of new drug delivery systems based on orally administered recombinant yeasts and that TIM-1 could be a helpful tool for the pre-screening of oral dosage forms.

  14. Graphene oxide for acid catalyzed-reactions: Effect of drying process

    Science.gov (United States)

    Gong, H. P.; Hua, W. M.; Yue, Y. H.; Gao, Z.

    2017-03-01

    Graphene oxides (GOs) were prepared by Hummers method through various drying processes, and characterized by XRD, SEM, FTIR, XPS and N2 adsorption. Their acidities were measured using potentiometric titration and acid-base titration. The catalytic properties were investigated in the alkylation of anisole with benzyl alcohol and transesterification of triacetin with methanol. GOs are active catalysts for both reaction, whose activity is greatly affected by their drying processes. Vacuum drying GO exhibits the best performance in transesterification while freezing drying GO is most active for alkylation. The excellent catalytic behavior comes from abundant surface acid sites as well as proper surface functional groups, which can be obtained by selecting appropriate drying process.

  15. Physical and immunogenic stability of spray freeze-dried influenza vaccine powder for pulmonary delivery : Comparison of inulin, dextran, or a mixture of dextran and trehalose as protectants

    NARCIS (Netherlands)

    Murugappan, Senthil; Patil, Harshad P; Kanojia, Gaurav; ter Veer, Wouter; Meijerhof, Tjarko; Frijlink, Henderik W; Huckriede, Anke; Hinrichs, Wouter L J

    2013-01-01

    One of the advantages of dry influenza vaccines over conventional liquid influenza vaccines is that they can be used for alternative routes of administration. Previous studies showed that spray freeze-drying is an excellent technique to prepare vaccine containing powders for pulmonary delivery U.P.

  16. Influence of Freeze-Dried Yeast Starter Cultures on Volatile Compounds of Tchapalo, a Traditional Sorghum Beer from Côte d’Ivoire

    Directory of Open Access Journals (Sweden)

    Wahauwouélé Hermann Coulibaly

    2016-12-01

    Full Text Available The production of the Ivorian sorghum beer known as tchapalo remains more or less an empirical process. The use of starter cultures was therefore suggested as the appropriate approach to alleviate the problems of variations in organoleptic quality and microbiological stability. In this study, we evaluated the capacity of S. cerevisiae and C. tropicalis to produce sorghum beer as freeze-dried starter in mixed or pure cultures. Beers produced with mixed freeze-dried cultures of S. cerevisiae F12-7 and C. tropicalis C0-7 showed residual sugars and ethanol contents similar to beers obtained with S. cerevisiae F12-7 pure culture, but the total sum of organic acids analyzed was the highest with the mixed culture (15.71 g/L. Higher alcohols were quantitatively the largest group of volatile compounds detected in beers. Among these compounds, 2-phenyl ethanol, a higher alcohol that  plays an important role in beer flavor, was highly produced with the mixed culture (10,174.8 µg/L than with the pure culture (8749.9 µg/L.

  17. Spray drying technique. I: Hardware and process parameters.

    Science.gov (United States)

    Cal, Krzysztof; Sollohub, Krzysztof

    2010-02-01

    Spray drying is a transformation of feed from a fluid state into a dried particulate form by spraying the feed into a hot drying medium. The main aim of drying by this method in pharmaceutical technology is to obtain dry particles with desired properties. This review presents the hardware and process parameters that affect the properties of the dried product. The atomization devices, drying chambers, air-droplet contact systems, the collection of dried product, auxiliary devices, the conduct of the spray drying process, and the significance of the individual parameters in the drying process, as well as the obtained product, are described and discussed.

  18. Ketahanan Hidup Sel Acetobacter xylinum pada Pengawetan secara Kering-Beku Menggunakan Medium Pembawa (Viability of A. xylinum Subjected to Freeze Drying Using Carrier Media

    Directory of Open Access Journals (Sweden)

    Noor Aini Habibah

    2009-03-01

    Full Text Available A research on the use of sucrose and lactose as carrier media to protect Acetobacter xylinum cell subjected to freeze drying has been done. The aim of the research was to know the number of the viable cells from dried culture and to know the concentration of the carrier medium that would give best result. The best result is sucrose at the concentration of 15% that produced 28.2 x 106 viable cells/ ml of rehidrated culture. The rehidrated culture used in the research was Schramm & Herstin medium. Key words : Acetobacter xylinum, freeze drying, carrier media

  19. Influence of product thickness, chamber pressure and heating conditions on production rate of freeze-dried yoghurt

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, N.K. [G.B. Pant Univ., of Agriculture and Technology (India). Dept. of Mechanical Engineering; Arora, C.P. [Indian Inst. of Tech., New Delhi (India)

    1995-06-01

    The effects of product thickness, chamber pressure and heating conditions on product temperature profiles and production rate of freeze-dried yoghurt were investigated experimentally. Three sample thicknesses - 3.8 mm, 6.2 mm and 9.4 mm - were tested at chamber pressures of 0.01 and 0.5 mmHg. The production rate increased by decreasing product thickness in contact heating through the bottom of the frozen layer, whereas no significant change was observed in radiant heating. A reduction in chamber pressure from 0.50 to 0.01 mmHg increased the drying time in radiant heating. Maximum production rate was obtained when the thickness of dried product was 6.2 mm, when heat was transferred simultaneously through the frozen and dried layers, and the chamber pressure was at 0.01 mmHg. Use of the product tray developed in this study prevents the growth of dry layers at the contact surfaces. (Author)

  20. A New Freeze Concentration Process for Minimum Effluent Process in Bleached Pulp

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Ru-Ying; Botsaris, Gregory D.

    2001-03-06

    This project researches freeze concentration as a primary volume reduction technology for bleaching plant effluents from paper-pulp mills before they are treated by expensive technologies, such as incineration, for the destruction of the adsorbable organic halogens. Previous laboratory studies show that freeze concentration has a greater than 99.5% purification efficiency for volatile, semivolatile, and nonprocess elements, or any other solute, thus producing pure ice that can be reused in the mill as water. The first section evaluates the anticipated regulatory and public pressures associated with implementing the technology; the remaining sections deal with the experimental results from a scaled-up freeze concentration process in a 100-liter pilot-plant at Tufts University. The results of laboratory scale experiments confirmed that the freeze concentration technology could be an efficient volume reduction technology for the above elements and for removing adsorbable organic hologens and or nonprocess elements from recycled water. They also provide the necessary data for designing and operating a larger pilot plant, and identify the technical problems encountered in the scale-up and the way they could be addressed in the larger scale plants. This project was originally planned to include the operation of a large pilot plant in the facilities of Swenson Process Equipment Inc., and a field test at a pulp mill, but the paper company withdrew its financial support for the field test. In place of a final economic evaluation after the field test, a preliminary evaluation based on the small pilot plant data predicts an economically reasonable freeze concentration process in the case of reduction of the bleaching-effluent flow to less than 5 m3/kkg pulp, a target anticipated in the near future.

  1. A New Freeze Concentration Process for Minimum Effluent Process in Bleached Pulp

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Ru-Ying; Botsaris, Gregory D.

    2001-03-06

    This project researches freeze concentration as a primary volume reduction technology for bleaching plant effluents from paper-pulp mills before they are treated by expensive technologies, such as incineration, for the destruction of the adsorbable organic halogens. Previous laboratory studies show that freeze concentration has a greater than 99.5% purification efficiency for volatile, semivolatile, and nonprocess elements, or any other solute, thus producing pure ice that can be reused in the mill as water. The first section evaluates the anticipated regulatory and public pressures associated with implementing the technology; the remaining sections deal with the experimental results from a scaled-up freeze concentration process in a 100-liter pilot-plant at Tufts University. The results of laboratory scale experiments confirmed that the freeze concentration technology could be an efficient volume reduction technology for the above elements and for removing adsorbable organic hologens and or nonprocess elements from recycled water. They also provide the necessary data for designing and operating a larger pilot plant, and identify the technical problems encountered in the scale-up and the way they could be addressed in the larger scale plants. This project was originally planned to include the operation of a large pilot plant in the facilities of Swenson Process Equipment Inc., and a field test at a pulp mill, but the paper company withdrew its financial support for the field test. In place of a final economic evaluation after the field test, a preliminary evaluation based on the small pilot plant data predicts an economically reasonable freeze concentration process in the case of reduction of the bleaching-effluent flow to less than 5 m3/kkg pulp, a target anticipated in the near future.

  2. Radioactive Dry Process Material Treatment Technology Development

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. J.; Hung, I. H.; Kim, K. K. (and others)

    2007-06-15

    The project 'Radioactive Dry Process Material Treatment Technology Development' aims to be normal operation for the experiments at DUPIC fuel development facility (DFDF) and safe operation of the facility through the technology developments such as remote operation, maintenance and pair of the facility, treatment of various high level process wastes and trapping of volatile process gases. DUPIC Fuel Development Facility (DFDF) can accommodate highly active nuclear materials, and now it is for fabrication of the oxide fuel by dry process characterizing the proliferation resistance. During the second stage from march 2005 to February 2007, we carried out technology development of the remote maintenance and the DFDF's safe operation, development of treatment technology for process off-gas, and development of treatment technology for PWR cladding hull and the results was described in this report.

  3. Effect of freeze dried powdered probiotics on gingival status and plaque inhibition: A randomized, double-blind, parallel study

    Directory of Open Access Journals (Sweden)

    Asif Yousuf

    2017-01-01

    Full Text Available Objective: The study aimed to evaluate the effectiveness of freeze dried powdered probiotics on gingival status and plaque inhibition among 12–15-year-old schoolchildren. Materials and Methods: This randomized controlled trial was conducted among 12–15-year-old schoolchildren in Jaipur. Commercially available freeze dried probiotics containing Lactobacillus acidophilus, Bifidobacterium longum, Bifidobacterium bifidum and Bifidobacterium lactis (Prowel, Alkem Laboratories, lactic acid bacillus only (Sporolac, Sangyo, and a placebo powder calcium carbonate 250 g (Calcium Sandoz, Novartis were assigned to two intervention groups and a placebo group each comprising 11 schoolchildren. All subjects were instructed to mix the powder in 30 ml of water and swish once daily for 3 min, for 3 weeks. Periodontal clinical parameters were assessed by examining the subjects for Turesky-Gilmore-Glickman plaque index (PI (Modification of Quigley-Hein PI and gingival index at baseline, 7th day, 14th day, and 21st day. Results: For both the probiotic groups, a statistically significant reduction (P < 0.05 in gingival status and plaque inhibition was recorded up to 2nd week of probiotic ingestion. However, no significant difference was observed in the placebo group. Conclusion: The use of probiotic mouth rinses improves the oral health in children by significantly reducing the plaque and gingival scores. Further studies are warranted to prove or refute the long-term effects, means of administering probiotics and the dosages needed to achieve different preventive or therapeutic purposes.

  4. Optimisation of phenolic extraction from Averrhoa carambola pomace by response surface methodology and its microencapsulation by spray and freeze drying.

    Science.gov (United States)

    Saikia, Sangeeta; Mahnot, Nikhil Kumar; Mahanta, Charu Lata

    2015-03-15

    Optimised of the extraction of polyphenol from star fruit (Averrhoa carambola) pomace using response surface methodology was carried out. Two variables viz. temperature (°C) and ethanol concentration (%) with 5 levels (-1.414, -1, 0, +1 and +1.414) were used to design the optimisation model using central composite rotatable design where, -1.414 and +1.414 refer to axial values, -1 and +1 mean factorial points and 0 refers to centre point of the design. The two variables, temperature of 40°C and ethanol concentration of 65% were the optimised conditions for the response variables of total phenolic content, ferric reducing antioxidant capacity and 2,2-diphenyl-1-picrylhydrazyl scavenging activity. The reverse phase-high pressure liquid chromatography chromatogram of the polyphenol extract showed eight phenolic acids and ascorbic acid. The extract was then encapsulated with maltodextrin (⩽ DE 20) by spray and freeze drying methods at three different concentrations. Highest encapsulating efficiency was obtained in freeze dried encapsulates (78-97%). The obtained optimised model could be used for polyphenol extraction from star fruit pomace and microencapsulates can be incorporated in different food systems to enhance their antioxidant property.

  5. Influence of compression on water sorption, glass transition, and enthalpy relaxation behavior of freeze-dried amorphous sugar matrices.

    Science.gov (United States)

    Imamura, Koreyoshi; Kagotani, Ryo; Nomura, Mayo; Tanaka, Kazuhiro; Kinugawa, Kohshi; Nakanishi, Kazuhiro

    2011-04-15

    An amorphous matrix comprised of sugar molecules are frequently used in the pharmaceutical industry. The compression of the amorphous sugar matrix improves the handling. Herein, the influence of compression on the water sorption of an amorphous sugar matrix was investigated. Amorphous sugar samples were prepared by freeze-drying, using several types of sugars, and compressed at 0-443 MPa. The compressed amorphous sugar samples as well as uncompressed samples were rehumidified at given RHs, and the equilibrium water content and glass transition temperature (T(g)) were then measured. Compression resulted in a decrease in the equilibrium water content of the matrix, the magnitude of which was more significant for smaller sized sugars. Diffusivity of water vapor in the sample was also decreased to one-hundredth by the compression. The T(g) value for a given RH remained unchanged, irrespective of the compression. Accordingly, the decrease in T(g) with increasing water content increased as the result of compression. The structural relaxation of the amorphous sugar matrices were also examined and found to be accelerated to the level of a non-porous amorphous sugar matrix as the result of the compression. The findings indicate that pores contained in freeze-dried sugar samples interfere with the propagation of structural relaxation.

  6. Bioactivity of freeze-dried platelet-rich plasma in an adsorbed form on a biodegradable polymer material.

    Science.gov (United States)

    Nakajima, Yu; Kawase, Tomoyuki; Kobayashi, Mito; Okuda, Kazuhiro; Wolff, Larry F; Yoshie, Hiromasa

    2012-01-01

    Owing to the necessity for the immediate preparation from patients' blood, autologous platelet-rich plasma (PRP) limits its clinical applicability. To address this concern and respond to emergency care and other unpredictable uses, we have developed a freeze-dried PRP in an adsorbed form on a biodegradable polymer material (Polyglactin 910). On the polymer filaments of PRP mesh, which was prepared by coating the polymer mesh with human fresh PRP and subsequent freeze-drying, platelets were incorporated, and related growth factors were preserved at high levels. This new PRP mesh preparation significantly and reproducibly stimulated the proliferation of human periodontal ligament cells in vitro and neovascularization in a chorioallantoic membrane assay. A full-thickness skin defect model in a diabetic mouse demonstrated the PRP mesh, although prepared from human blood, substantially facilitated angiogenesis, granulation tissue formation, and re-epithelialization without inducing severe inflammation in vivo. These data demonstrate that our new PRP mesh preparation functions as a bioactive material to facilitate tissue repair/regeneration. Therefore, we suggest that this bioactive material, composed of allogeneic PRP, could be clinically used as a promising alternative in emergency care or at times when autologous PRP is not prepared immediately before application.

  7. Freeze drying of peptide drugs self-associated with long-circulating, biocompatible and biodegradable sterically stabilized phospholipid nanomicelles.

    Science.gov (United States)

    Lim, Sok Bee; Rubinstein, Israel; Onyüksel, Hayat

    2008-05-22

    The purpose of this study was to determine optimal lipid concentration range for lyophilization of sterically stabilized phospholipid nanomicelles (SSM) and the freeze drying feasibility of self-associated therapeutic peptide-SSM assemblies. SSM at 5-20 mM 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy-poly(ethylene glycol 2000) (DSPE-PEG(2000)) were analyzed for particle size and viscosity before and after freeze drying which showed no significant changes (p>0.05). However, a steep increase in viscosity was seen for SSM above 15 mM phospholipid implying micelle-micelle interaction. Greater shrinkage of lyophilized cakes was observed below 10 mM phospholipid while they were more fibrous above 15 mM. Therefore, 10-15 mM DSPE-PEG(2000) was chosen as the optimal phospholipid concentration for lyophilized SSM. When vasoactive intestinal peptide (VIP), glucagon-like peptide 1 (GLP-1) or gastric inhibitory peptide (GIP) (each, 67 microM) was added to SSM (10mM), formulations showed no significant change in particle size, peptide fluorescence and peptide alpha-helicity before and after lyophilization. In conclusion, we found that peptide drug-SSM interactions are conserved during lyophilization.

  8. Evaluation of Different Holder Devices for Freeze-Drying in Dual-Chamber Cartridges With a Focus on Energy Transfer.

    Science.gov (United States)

    Korpus, Christoph; Friess, Wolfgang

    2017-04-01

    For freeze-drying in dual-chamber cartridges, a holder device to enable handling and safe positioning in the freeze-dryer is necessary. The aim of this study was to analyze 4 different types of holder devices and to define the best system based on energy transfer. The main criteria were drying homogeneity, ability to minimize the influence of atypical radiation on product temperatures, and heat transfer effectiveness. The shell holder reduced the influence of atypical radiation by almost 60% compared to a block system and yielded the most homogenous sublimation rates. Besides the most efficient heat transfer with values of 1.58E-4 ± 2.06E-6 cal/(s*cm(2)*K) at 60 mTorr to 3.63E-4 ± 1.85E-5 cal/(s*cm(2)*K) at 200 mTorr for Ktot, reaction times to shelf temperature changes were up to 4 times shorter compared to the other holder systems and even faster than for vials. The flexible holder provided a comparable shielding against atypical radiation as the shell but introduced a third barrier against energy transfer. Block and guardrail holder were the least efficient system tested. Hence, the shell holder provided the best radiation shielding, enhanced the transferability of the results to a larger scale, and improved the homogeneity between the dual-chamber cartridges.

  9. Vial freeze-drying, part 1: new insights into heat transfer characteristics of tubing and molded vials.

    Science.gov (United States)

    Hibler, Susanne; Wagner, Christophe; Gieseler, Henning

    2012-03-01

    In order to optimize a freeze-drying cycle, information regarding the heat transfer characteristics of the container system is imperative. Two most recently developed tubing (TopLyo™) and molded (EasyLyo™) vial designs were compared with a standard serum tubing and molded vial, a polymer vial (TopPac™), and an amber molded EasyLyo™. In addition, the impact of methodology on the determination of reliable vial heat transfer coefficient (K(v) ) data is examined in detail. All K(v) s were gravimetrically determined by sublimation tests with pure water at 50, 100, 200, and 400 mTorr. In contrast to the traditional assumption that molded vials exhibit inefficient heat transfer characteristics, these vials showed a very similar performance compared with their serum tubing counterparts in the relevant pressure range for freeze-drying. At 100 mTorr, the TopLyo™ center vials show only 4% higher K(v) values than the EasyLyo™ center vials. All glass vials outmatch the polymer vial in terms of heat transfer, up to 30% elevated heat transfer for the TopLyo™ center vials at 400 mTorr. Sublimation tests have demonstrated to be a valuable tool to investigate the heat transfer characteristics of vials, but results are dependent on methodology. New developments in molded vial manufacturing lead to improved heat transfer performance.

  10. Beef, chicken and lamb fatty acid analysis--a simplified direct bimethylation procedure using freeze-dried material.

    Science.gov (United States)

    Lee, M R F; Tweed, J K S; Kim, E J; Scollan, N D

    2012-12-01

    When fractionation of meat lipids is not required, procedures such as saponification can be used to extract total fatty acids, reducing reliance on toxic organic compounds. However, saponification of muscle fatty acids is laborious, and requires extended heating times, and a second methylation step to convert the extracted fatty acids to fatty acid methyl esters prior to gas chromatography. Therefore the development of a more rapid direct methylation procedure would be of merit. The use of freeze-dried material for analysis is common and allows for greater homogenisation of the sample. The present study investigated the potential of using freeze-dried muscle samples and a direct bimethylation to analyse total fatty acids of meat (beef, chicken and lamb) in comparison with a saponification procedure followed by bimethylation. Both methods compared favourably for all major fatty acids measured. There was a minor difference in relation to the C18:1 trans 10 isomer with a greater (Psaponification. However, numerically the difference was small and likely as a result of approaching the limits of isomer identification by single column gas chromatography. Differences (Psaponification to analyse total fatty acids from muscle samples.

  11. Evaluation of Genotoxicity and 28-day Oral Dose Toxicity on Freeze-dried Powder of Tenebrio molitor Larvae (Yellow Mealworm).

    Science.gov (United States)

    Han, So-Ri; Yun, Eun-Young; Kim, Ji-Young; Hwang, Jae Sam; Jeong, Eun Ju; Moon, Kyoung-Sik

    2014-06-01

    The larval form of Tenebrio molitor (T. molitor) has been eaten in many countries and provides benefits as a new food source of protein for humans. However, no information exists regarding its safety for humans. The objective of the present study was to evaluate the genotoxicity and repeated dose oral toxicity of the freeze-dried powder of T. molitor larvae. The genotoxic potential was evaluated by a standard battery testing: bacterial reverse mutation test, in vitro chromosome aberration test, and in vivo micronucleus test. To assess the repeated dose toxicity, the powder was administered once daily by oral gavage to Sprague-Dawley (SD) rats at dose levels of 0, 300, 1000 and 3000 mg/kg/day for 28 days. The parameters which were applied to the study were mortality, clinical signs, body and organ weights, food consumption, ophthalmology, urinalysis, hematology, serum chemistry, gross findings and histopathologic examination. The freezedried powder of T. molitor larvae was not mutagenic or clastogenic based on results of in vitro and in vivo genotoxicity assays. Furthermore, no treatment-related changes or findings were observed in any parameters in rats after 28 days oral administration. In conclusion, the freeze-dried powder of T. molitor larvae was considered to be non-genotoxic and the NOAEL (No Observed Adverse Effect Level) was determined to be 3000 mg/kg/day in both sexes of SD rats under our experimental conditions.

  12. Effects of the soil freeze-thaw process on the regional climate of the Tibet Plateau

    Science.gov (United States)

    Luo, S., Sr.; Chen, B.; Lu, S.; Zhang, Y.; Ma, D.

    2015-12-01

    Single-point and regional simulation experiments on the Tibet Plateau, both with and without consideration of the soil freeze-thaw process, were set up with CLM3.5 and RegCM4 models. Comparison of the simulated soil temperature and moisture, surface energy flux, and upper-lower atmospheric circulation showed that the regional climate can be influenced by the freeze-thaw process of soil. The results indicate that the freeze-thaw process is a buffer to the seasonal changes in soil and near-surface temperatures and strengthens the energy exchange between the soil and the atmosphere. During the freeze (thaw) process, releasing (absorbing) of phase change energy retards the cooling (heating) effect of air temperature on soil. The soil freeze-thaw process increases (decreases) the surface heat source of the plateau in winter (summer), which increases (decreases) the near-surface temperature in winter (summer). Promoted by atmospheric circulation, the soil freeze-thaw process influences climate at the high and low altitudes of the plateau; this may also contribute to the maintenance of the South Asia High. In the early stages of permafrost degradation, the regional climate effects of freezing and thawing may accelerate the degradation of permafrost.

  13. Heat and Mass Transfer of Droplet Vacuum Freezing Process Based on Dynamic Mesh

    Directory of Open Access Journals (Sweden)

    Lili Zhao

    2014-01-01

    Full Text Available A numerical simulation using dynamic mesh method by COMSOL has been developed to model heat and mass transfer during vacuum freezing by evaporation of a single droplet. The initial droplet diameter, initial droplet temperature, and vacuum chamber pressure effect are studied. The surface and center temperature curve was predicted to show the effect. The mass transfer rate and radius displacement were also calculated. The results show the dynamic mesh shows well the freezing process with the radius reduction of droplet. The initial droplet diameter, initial droplet temperature, and vacuum pressure have obvious effect on freezing process. The total freezing time is about 200 s, 300 s, and 400 s for droplet diameter 7.5 mm, 10.5 mm, and 12.5 mm, respectively. The vacuum pressure less than 200 Pa is enough for the less time to freezing the droplet, that is, the key point in freezing time. The initial droplet temperature has obvious effect on freezing but little effect on freezing temperature.

  14. A heat equation for freezing processes with phase change

    DEFF Research Database (Denmark)

    Backi, Christoph Josef; Bendtsen, Jan Dimon; Leth, John-Josef

    2016-01-01

    In this work, the stability properties as well as possible applications of a partial differential equation (PDE) with state-dependent parameters are investigated. Among other things, the PDE describes freezing of foodstuff, and is closely related to the (potential) Burgers’ equation. We show...

  15. Investigation of Indirect Contact Freezing Process in Desalination of Boshehr Beach's Saline Water

    Directory of Open Access Journals (Sweden)

    M Alimohaadi

    2011-10-01

    Full Text Available Background and Objectives: Nowadays, most countries of the world have shortage of water due to many reasons such as population growth, rising of living standards, indiscriminate water use, and so on. Besides, in absence of adequate water resources, desalination of brackish and saline waters have been used to supply potable water. Freezing process is one of the methods which can be used to desalinate saline waters.The aim of this study was to survey freezing process to produce potable water from saline water of Persian Gulf shores."nMaterials and Methods: This study was conducted in lab-scale by using indirect contact freezing. Three samples of 50 liter were provided from Bushehr shores. The implemented process steps were freezing (crystallization, separation of crystals, surface washing, and thawing. Freezing of the samples (each in 0.5 liter containers were performed by a refrigerator at -20°C and 0.1KW/h energy consumption.Results: The removal efficiencies of TDS in the first, second, and third samples by first freezing process were 56, 56, and 51 percent, respectively. Moreover, the removal efficiencies by EC were 42, 44, and 40 percent, respectively. Meanwhile, the removal efficiencies of TDS in first, second, and third samples by second freezing process observed 69, 69, and 68 percent, respectively. Moreover, the removal efficiencies by EC were 61, 60, and 63 percent, respectively. Also, the removal efficiencies of TDS in first, second, and third samples by third freezing process were 72, 73, and 72 percent, respectively. Moreover, the removal efficiencies by EC were 77, 78, and 77 percent, respectively. The production of the potable water by this method was 15-20 percent of the entry water.Conclusions: According to the obtained results, potable water was obtained after third freezing of the saline water. Meanwhile, TDS of the produced water was less than maximum allowed concentration of Iranian standards.

  16. Vacuum Freezing and Drying Technology of Mulberry Fruit%桑果真空冷冻干燥技术研究

    Institute of Scientific and Technical Information of China (English)

    秦晋军; 乔邓君; 张洁花; 罗锋; 韩睿; 闫伟

    2015-01-01

    Dashi mulberry was taken to measure the eutectic point and cosolvent point of mulberry vacuum freezing and dr‐ying ,which were‐23℃ and‐20℃ respectively .The final freezing temperature was‐33 to‐28℃ .The lyophilization trend during the drying process was analyzed and the factors affecting the quality and yield of the lyophilized product were also measured and studied .The results show that when mulberries were evenly laid on the plate and quickly frozen when they are not fully ripen ,the best quality of lyophilized product can be achieved by adopting second stage temperature control curve at sublimation drying period and keeping the heating plate at 35℃ at drying period .%以大十桑果为原料,测得桑果真空冷冻干燥的共晶点和共溶点分别为-23℃和-20℃,冻结的最终温度为-33~-28℃。分析干燥过程中冻干曲线变化趋势;并对影响冻干品质量和产量因素进行测试研究。结果表明:桑果成熟度为八九成熟,装盘时单层平放,以速冻方法冻结,在升华干燥阶段采用二段温控曲线,在解析干燥阶段将加热板最高温度控制在35℃,加工出来的冻干品质量最好,保质期长。

  17. Effect of whey protein isolate and β-cyclodextrin wall systems on stability of microencapsulated vanillin by spray-freeze drying method.

    Science.gov (United States)

    Hundre, Swetank Y; Karthik, P; Anandharamakrishnan, C

    2015-05-01

    Vanillin flavour is highly volatile in nature and due to that application in food incorporation is limited; hence microencapsulation of vanillin is an ideal technique to increase its stability and functionality. In this study, vanillin was microencapsulated for the first time by non-thermal spray-freeze-drying (SFD) technique and its stability was compared with other conventional techniques such as spray drying (SD) and freeze-drying (FD). Different wall materials like β-cyclodextrin (β-cyd), whey protein isolate (WPI) and combinations of these wall materials (β-cyd + WPI) were used to encapsulate vanillin. SFD microencapsulated vanillin with WPI showed spherical shape with numerous fine pores on the surface, which in turn exhibited good rehydration ability. On the other hand, SD powder depicted spherical shape without pores and FD encapsulated powder yielded larger particle sizes with flaky structure. FTIR analysis confirmed that there was no interaction between vanillin and wall materials. Moreover, spray-freeze-dried vanillin + WPI sample exhibited better thermal stability than spray dried and freeze-dried microencapsulated samples.

  18. Multivariate Analysis of Phenol in Freeze-Dried and Spray-Dried Insulin Formulations by NIR and FTIR

    OpenAIRE

    Maltesen, Morten Jonas; Bjerregaard, Simon; Hovgaard, Lars; Havelund, Svend; van de Weert, Marco; Grohganz, Holger

    2011-01-01

    Dehydration is a commonly used method to stabilise protein formulations. Upon dehydration, there is a significant risk the composition of the formulation will change especially if the protein formulation contains volatile compounds. Phenol is often used as excipient in insulin formulations, stabilising the insulin hexamer by changing the secondary structure. We have previously shown that it is possible to maintain this structural change after drying. The aim of this study was to evaluate the ...

  19. Development of Three-Layer Simulation Model for Freezing Process of Food Solution Systems

    Science.gov (United States)

    Kaminishi, Koji; Araki, Tetsuya; Shirakashi, Ryo; Ueno, Shigeaki; Sagara, Yasuyuki

    A numerical model has been developed for simulating freezing phenomena of food solution systems. The cell model was simplified to apply to food solution systems, incorporating with the existence of 3 parts such as unfrozen, frozen and moving boundary layers. Moreover, the moving rate of freezing front model was also introduced and calculated by using the variable space network method proposed by Murray and Landis (1957). To demonstrate the validity of the model, it was applied to the freezing processes of coffee solutions. Since the model required the phase diagram of the material to be frozen, the initial freezing temperatures of 1-55 % coffee solutions were measured by the DSC method. The effective thermal conductivity for coffee solutions was determined as a function of temperature and solute concentration by using the Maxwell - Eucken model. One-dimensional freezing process of 10 % coffee solution was simulated based on its phase diagram and thermo-physical properties. The results were good agreement with the experimental data and then showed that the model could accurately describe the change in the location of the freezing front and the distributions of temperature as well as ice fraction during a freezing process.

  20. Study on foam freeze drying in vaccine%疫苗的泡沫冷冻干燥研究

    Institute of Scientific and Technical Information of China (English)

    张绍志; 施铭耀; 陈光明; 吕芳; 卢宇

    2013-01-01

    Freeze‐drying has been widely used in the production of pharmaceuticals , vaccines and high‐valued foods . Foam freeze‐drying is a new type of drying technology , in which the sample is foamed and frozen before drying . Compared with traditional freeze‐drying method , the new method can reduce operation time and cost significantly . Some foreign researchers have used this method to produce heat‐resistant vaccines which can endure higher temperature and remain effective after a longer storage in refrigerator . Up to now , little research about foam freeze‐drying has been reported domestically . In this study , newcastle disease vaccine was used as an example to illustrate the procedure of foam freeze‐drying method and to test its capability of producing heat‐resistant vaccine . The ingredient of the foam freeze drying ( FFD ) sample included w ( trehalose) = 10% , w ( hydrolyzed gelatin) = 5% , w( pluronic F‐108) = 3% , w( arginine) = 2% , 25 mmol/L phosphate buffer ( pH = 7 .2) . The sample was prepared through the following procedure:1) One milliliter sample was placed on the plate of the freeze dryer and cooled to 15 ℃ ;2) then the pressure was lowered to 5 Pa and foaming began;3) after one hour the plate temperature was increased up to 31 ℃ at a velocity of 0 .7 ℃ /min and kept for another 48 hours . The samples made by foam freeze drying were analyzed with thermal analysis and aging test , and were compared with live attenuated samples and heat‐resistant samples prepared by traditional freeze drying . The latter two kinds of sample were bought from market ( Tianbang Biotechnology Corporation , Nanjing , China) . Thermal analysis was done with a differential scanning calorimetry (DSC 200 F3 Maia , NETZSCH , Germany) . The procedure was as follows:1) the sample was cooled to -20 ℃ at a rate of 10 ℃ /min and held for 3 minutes;2) the sample was heated to 80 ℃ at the rate of 10 ℃/min and held for 3 minutes;3) the sample was cooled

  1. Freeze Technology for Nuclear Applications - 13590

    Energy Technology Data Exchange (ETDEWEB)

    Rostmark, Susanne C.; Knutsson, Sven [Lulea University of Technology (Sweden); Lindberg, Maria [Studsvik Nuclear AB, 611 82 Nykoeping (Sweden)

    2013-07-01

    Freezing of soil materials is a complicated process of a number of physical processes: - freezing of pore water in a thermal gradient, - cryogenic suction causing water migration and - ice formation expanding pores inducing frost heave. Structural changes due to increase of effective stress during freezing also take place. The over consolidation gives a powerful dewatering/drying effect and the freeze process causes separation of contaminates. Artificial ground freezing (AGF is a well established technique first practiced in south Wales, as early as 1862. AGF is mostly used to stabilize tunnels and excavations. During the last ten years underwater applications of freeze technologies based on the AGF have been explored in Sweden. The technology can, and has been, used in many different steps in a remediation action. Freeze Sampling where undisturbed samples are removed in both soft and hard sediment/sludge, Freeze Dredging; retrieval of sediment with good precision and minimal redistribution, and Freeze Drying; volume reduction of contaminated sludge/sediment. The application of these technologies in a nuclear or radioactive environment provides several advantages. Sampling by freezing gives for example an advantage of an undisturbed sample taken at a specified depth, salvaging objects by freezing or removal of sludges is other applications of this, for the nuclear industry, novel technology. (authors)

  2. Freeze-Spray Processing of Layered Ceramic Composites (Preprint)

    Science.gov (United States)

    2006-04-01

    remove the ice by sublimation . In order to study the effect of green density on the sintered microstructure, a set of samples were isostatically...Ceram. Forum Int., 79 ( 9 , E35-E38, (2002). ’K. Araki and J. W. Halloran, "Room-Temperature Freeze Casting for Ceramics with Nonaqueous Sublimable ...Vehicles in the Naphtalene- Camphor Eutectic System," J. Am. Cerum Soc. 87 (1 1) 2014-2019 (2004). 9 ~ . Reed, Introduction to the Principles of

  3. The Research Status and Prospects of the Hot Air Drying and Freeze Drying for Papaya%木瓜热风干燥和冷冻干燥的研究现状和展望

    Institute of Scientific and Technical Information of China (English)

    李铭; 陈冬梅; 侯萍; 赵鹤飞; 余善鸣

    2013-01-01

    果蔬的干燥主要有热干、微波、冻干和组合干燥。木瓜的干燥以热干为主,冻干能最大程度保持木瓜的色泽、风味和营养价值,但研究报道较少。今后木瓜干燥研究的主要内容将是提高品质和降低产品成本。因此,木瓜的热干和冻干的组合干燥将是研究的重点。%The primary drying technologys of fruits and vegetables are hot-air drying , microwave drying , freeze drying and combined drying. The mainly drying method of papaya is hot-air drying. The freeze-dried can keep the greatest degree of color, flavor and nutritional value of papaya, However, it is lack of references on that. Future research of the drying technology of papaya will be improvement of the quality and to reduce product cost. Therefore, the combined drying technology of hot-air and freeze of papaya will become a study emphasis in further research.

  4. Dynamic investigation on the coupled changing process of moisture and density fields in freezing soil

    Institute of Scientific and Technical Information of China (English)

    张立新; 蒲毅彬; 廖全荣; 顾同欣

    1999-01-01

    The data reflecting the change in density are obtained, with computer tomograph scanning through the sample of freezing soil section by section at intervals without destruction. Combined with the changing characteristics of water content along the sample during test, the dynamic coupled process of moisture and density fields under the effect of temperature gradient on the freezing soil in closed system is discussed. The result reflects the internal process of frost heave improvement resulting from the transfer of mass and heat.

  5. Stability of Staphylococcus aureus phage ISP after freeze-drying (lyophilization).

    Science.gov (United States)

    Merabishvili, Maia; Vervaet, Chris; Pirnay, Jean-Paul; De Vos, Daniel; Verbeken, Gilbert; Mast, Jan; Chanishvili, Nino; Vaneechoutte, Mario

    2013-01-01

    Staphylococcus aureus phage ISP was lyophilized, using an Amsco-Finn Aqua GT4 freeze dryer, in the presence of six different stabilizers at different concentrations. Stability of the lyophilized phage at 4 °C was monitored up to 37 months and compared to stability in Luria Bertani broth and physiological saline at 4 °C. Sucrose and trehalose were shown to be the best stabilizing additives, causing a decrease of only 1 log immediately after the lyophilization procedure and showing high stability during a 27 month storage period.

  6. Stability of Staphylococcus aureus phage ISP after freeze-drying (lyophilization.

    Directory of Open Access Journals (Sweden)

    Maia Merabishvili

    Full Text Available Staphylococcus aureus phage ISP was lyophilized, using an Amsco-Finn Aqua GT4 freeze dryer, in the presence of six different stabilizers at different concentrations. Stability of the lyophilized phage at 4 °C was monitored up to 37 months and compared to stability in Luria Bertani broth and physiological saline at 4 °C. Sucrose and trehalose were shown to be the best stabilizing additives, causing a decrease of only 1 log immediately after the lyophilization procedure and showing high stability during a 27 month storage period.

  7. Freeze-dried allograft-mediated gene or protein delivery of growth and differentiation factor 5 reduces reconstructed murine flexor tendon adhesions

    DEFF Research Database (Denmark)

    Svensson, Sys Hasslund; Dadali, Tulin; Ulrich-Vinther, Michael

    2014-01-01

    Advances in allograft processing have opened new horizons for clinical adaptation of flexor tendon allografts as delivery scaffolds for antifibrotic therapeutics. Recombinant adeno-associated-virus (rAAV) gene delivery of the growth and differentiation factor 5 (GDF-5) has been previously...... associated with antifibrotic effects in a mouse model of flexor tendoplasty. In this study, we compared the effects of loading freeze-dried allografts with different doses of GDF-5 protein or rAAV-Gdf5 on flexor tendon healing and adhesions. We first optimized the protein and viral loading parameters using...... reverse transcription polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and in vivo bioluminescent imaging. We then reconstructed flexor digitorum longus (FDL) tendons of the mouse hindlimb with allografts loaded with low and high doses of recombinant GDF-5 protein and r...

  8. Visualization data on the freezing process of micrometer-scaled aqueous citric acid drops

    Directory of Open Access Journals (Sweden)

    Anatoli Bogdan

    2017-02-01

    Full Text Available The visualization data (8 movies presented in this article are related to the research article entitled “Freezing and glass transitions upon cooling and warming and ice/freeze-concentration-solution morphology of emulsified aqueous citric acid” (A. Bogdan, M.J. Molina, H. Tenhu, 2016 [1]. The movies recorded in-situ with optical cryo-miscroscopy (OC-M demonstrate for the first time freezing processes that occur during the cooling and subsequent warming of emulsified micrometer-scaled aqueous citric acid (CA drops. The movies are made publicly available to enable critical or extended analyzes.

  9. Influence of different sugar cryoprotectants on the stability and physico-chemical characteristics of freeze-dried 5-fluorouracil plurilamellar vesicles

    Directory of Open Access Journals (Sweden)

    Mohamed Mahmoud Nounou

    2005-07-01

    Full Text Available Lyophilization increases the shelf-life of liposomes by preserving it in a dry form as lyophilized cake to be reconstituted with water immediately prior to administration. Aiming at increasing stability and availability of 5-Fluorouracil liposomal products, 5-Fluorouacil Stable Plurilamellar Vesicles were prepared. Freeze dried liposomal dispersions were prepared with or without cryoprotectants. The cryoprotectants used were glucose, mannitol or trehalose in 1, 2 and 4 grams per gram phospholipids. The results showed that lyophilized cake of liposomes without cryoprotectants was compact and difficult to reconstitute, in comparison with fluffy cakes which reconstituted easily and quickly when using cryoprotectants. The percentage of 5-Fluorouracil retained in liposomes freeze-dried without cryoprotectants was 18.29% ± 0.96% and the percentage of 5-Fluorouracil retained in stable plurilamellar vesicles was 31.22% ± 0.62% using 4 grams trehalose as cryoprotectant per gram of lipid. Physico-chemical and release stability studies showed superior potentials of the lyophilized product after reconstitution in comparison to dispersion product. It may be concluded that all tested sugars have cryoprotectant effects that stabilized liposomes in the freeze dried state, where trehalose offered the most superior cryoprotectant effect for freeze dried 5-fluorouracil liposomes.

  10. Bilateral maxillary sinus floor augmentation with tissue-engineered autologous osteoblasts and demineralized freeze-dried bone

    Directory of Open Access Journals (Sweden)

    Aashish Deshmukh

    2015-01-01

    Full Text Available The pneumatization of the maxillary sinus often results in a lack of sufficient alveolar bone for implant placement. In the last decades, maxillary sinus lift has become a very popular procedure with predictable results. Sinus floor augmentation procedures are generally carried out using autologous bone grafts, bone substitutes, or composites of bone and bone substitutes. However, the inherent limitations associated with each of these, have directed the attention of investigators to new technologies like bone tissue engineering. Bone marrow stromal cells have been regarded as multi-potent cells residing in bone marrow. These cells can be harvested from a person, multiplied outside his body using bioengineering principles and technologies and later introduced into a tissue defect. We present a case where tissue-engineered autologous osteoblasts were used along with demineralized freeze-dried bone for sinus floor augmentation.

  11. The influence of different polymers on viability of Bifidobacterium lactis 300b during encapsulation, freeze-drying and storage.

    Science.gov (United States)

    Pop, Oana Lelia; Brandau, Thorsten; Schwinn, Jens; Vodnar, Dan Cristian; Socaciu, Carmen

    2015-07-01

    Seven different types of natural polymers namely hydroxypropyl methylcellulose (HPMC), sodium-carboxymethyl cellulose (Na-CMC), microcrystalline cellulose (MCC), starch BR-07, starch BR-08, dextrin and pullulan were used in order to develop the optimal formula for the entrapment of Bifidobacterium lactis 300B in Ca-alginate based granules. Laminar flow drip casting with Brace-Encapsulator was used in order to prepare the granules. The results showed that alginate/pullulan and alginate/HPMC formulation provide high protection for the bacterial strain used for encapsulation. These two formulations were further used to obtain freeze dried granules, for which the viability in time and at different temperatures was tested. The final results showed a higher viability than the level of the therapeutic minimum (>10(7) CFU/g) after 15 days of storage. Other parameters like entrapment efficiency, production rate, sphericity, flowability were also discussed.

  12. Treatment of Periradicular Bone Defect by Periosteal Pedicle Graft as a Barrier Membrane and Demineralized Freeze-Dried Bone Allograft

    Science.gov (United States)

    Saxena, Anurag

    2017-01-01

    The purpose of this case report is to describe the usefulness of Periosteal Pedicle Graft (PPG) as a barrier membrane and Demineralized Freeze-Dried Bone Allograft (DFDBA) for bone regeneration in periradicular bone defect. A patient with intraoral discharging sinus due to carious exposed pulp involvement was treated by PPG and DFDBA. Clinical and radiological evaluations were done immediately prior to surgery, three months, six months and one year after surgery. Patient was treated using split-thickness flap, PPG, apicoectomy, defect fill with DFDBA and lateral displacement along with suturing of the PPG prior to suturing the flap, in order to close the communication between the oral and the periapical surroundings through sinus tract opening. After one year, successful healing of periradicular bone defect was achieved. Thus, PPG as a barrier membrane and DFDBA have been shown to have the potential to stimulate bone formation when used in periradicular bone defect. PMID:28274066

  13. Healthy offspring from freeze-dried mouse spermatozoa held on the International Space Station for 9 months.

    Science.gov (United States)

    Wakayama, Sayaka; Kamada, Yuko; Yamanaka, Kaori; Kohda, Takashi; Suzuki, Hiromi; Shimazu, Toru; Tada, Motoki N; Osada, Ikuko; Nagamatsu, Aiko; Kamimura, Satoshi; Nagatomo, Hiroaki; Mizutani, Eiji; Ishino, Fumitoshi; Yano, Sachiko; Wakayama, Teruhiko

    2017-06-06

    If humans ever start to live permanently in space, assisted reproductive technology using preserved spermatozoa will be important for producing offspring; however, radiation on the International Space Station (ISS) is more than 100 times stronger than that on Earth, and irradiation causes DNA damage in cells and gametes. Here we examined the effect of space radiation on freeze-dried mouse spermatozoa held on the ISS for 9 mo at -95 °C, with launch and recovery at room temperature. DNA damage to the spermatozoa and male pronuclei was slightly increased, but the fertilization and birth rates were similar to those of controls. Next-generation sequencing showed only minor genomic differences between offspring derived from space-preserved spermatozoa and controls, and all offspring grew to adulthood and had normal fertility. Thus, we demonstrate that although space radiation can damage sperm DNA, it does not affect the production of viable offspring after at least 9 mo of storage on the ISS.

  14. Successful Resolution of Recurrent Clostridium difficile Infection using Freeze-Dried, Encapsulated Fecal Microbiota; Pragmatic Cohort Study.

    Science.gov (United States)

    Staley, Christopher; Hamilton, Matthew J; Vaughn, Byron P; Graiziger, Carolyn T; Newman, Krista M; Kabage, Amanda J; Sadowsky, Michael J; Khoruts, Alexander

    2017-06-01

    Fecal microbiota transplantation (FMT) is increasingly being used for treatment of recurrent Clostridium difficile infection (R-CDI) that cannot be cured with antibiotics alone. In addition, FMT is being investigated for a variety of indications where restoration or restructuring of the gut microbial community is hypothesized to be beneficial. We sought to develop a stable, freeze-dried encapsulated preparation of standardized fecal microbiota that can be used for FMT with ease and convenience in clinical practice and research. We systematically developed a lyophilization protocol that preserved the viability of bacteria across the taxonomic spectrum found in fecal microbiota and yielded physicochemical properties that enabled consistent encapsulation. We also treated a cohort of R-CDI patients with a range of doses of encapsulated microbiota and analyzed the associated changes in the fecal microbiome of the recipients. The optimized lyophilized preparation satisfied all our preset goals for physicochemical properties, encapsulation ease, stability at different temperatures, and microbiota viability in vitro and in vivo (germ-free mice). The capsule treatment was administered to 49 patients. Overall, 43/49 (88%) of patients achieved a clinical success, defined as no recurrence of CDI over 2 months. Analysis of the fecal microbiome demonstrated near normalization of the fecal microbial community by 1 month following FMT treatment. The simplest protocol using the lowest dose (2.1-2.5 × 10(11) bacteria in 2-3 capsules) without any colon purgative performed equally well in terms of clinical outcomes and microbiota engraftment. A single administration of encapsulated, freeze-dried fecal microbiota from a healthy donor was highly successful in treating antibiotic-refractory R-CDI syndrome.

  15. The repeated drying-wetting and freezing-thawing cycles affect only the active pool of soil organic matter

    Science.gov (United States)

    Semenov, Vyacheslav; Zinyakova, Natalya; Tulina, Anastasiya

    2016-04-01

    The decrease in the content of soil organic carbon, particularly in active form, is one of the major problems of the 21st century, which is closely related to the disturbance of the biogeochemical carbon cycle and to the increase in the emission of carbon dioxide into the atmosphere. The main reasons for the SOM losses are the surplus of the SOM active pool losses due to mineralization, erosion, and infiltration over the input of fresh organic matter to the soil, as well as the changes in the soil conditions and processes due to natural and anthropogenic disturbing impacts. Experiments were carried out with mixed samples from the upper layers of soddy-podzolic soil, gray forest soil, and typical chernozems. Soil samples as controls were incubated after wetting for 150 days. The dynamics and cumulative production of C-CO2 under stable temperature (22°C) and moisture conditions were determined; the initial content of potentially mineralizable organic matter (C0) in the soil at the beginning of the incubation was then calculated to use these data as the control. Other soil samples were exposed in flasks to the following successive treatments: wetting →incubation → freezing → thawing → incubation →drying. Six repeated cycles of disturbing impacts were performed for 140 days of the experiment. After six cycles, the soil samples were incubated under stable temperature and moisture conditions for 150 days. The wetting of dried soils and the thawing of frozen soils are accompanied by the pulsed dynamics of the C-CO2 production with an abrupt increase in the rate of the C-CO2 emission within several days by 2.7-12.4 and 1.6-2.7 times, respectively, compared to the stable incubation conditions. The rate of the C-CO2 production pulses under each subsequent impact decreased compared to the preceding one similarly for all studied soils, which could be due to the depletion in potentially mineralizable soil organic matter (C0). The cumulative extra C-CO2 production by

  16. 冻干对红阳猕猴桃果浆还原型抗坏血酸的影响%Effects of Freeze-drying Conditions on Reduced Ascorbic Acid of Hongyang Kiwifruit Pulps

    Institute of Scientific and Technical Information of China (English)

    郑晓琴; 陈彦; 李竞晋; 王林琳; 李明章

    2009-01-01

    The effects of pre-freezing methods,relative ratio surface(RRS) and the positions of container loading Hongyang Kiwifruit pulps in freezing chamber on the preservation rate of reduced ascorbic acid (RAA) during the freeze-drying processing were studied by orthogonal experimerits.The results showed that the pre-freezing methods and the RRS affected the preservation rate of RAA significandy in the freeze-drying process(p0.05).The preservation rate of RAA of Hongyang Kiwifruit pulps was more than 98% under the optimum freeze-drying conditions.The comparison of the lyophilized products and the hot-air drying products was also conducted in view of their sensory properties and physical-chemical indexes.Tne physical-chemical indexes (i.e.RAA preservation rate) and sensory properties of lyophilized Hongyang Kiwifruit pupls were superior to that of hot-air drying products.%以还原型抗坏血酸保存率为指标,采用正交试验方法研究了冻干中红阳(Hongyang)猕猴桃果浆料的预冻方式、相对比表面积、放置位置因素等的影响.结果表明,在冻干加工处理中,果浆料的预冻方式、相对比表面积因素等冻干工艺参数对红阳猕猴桃果浆还原型抗坏血酸的保存率影响极显著(p0.05),在优化冻干工艺条件下获得的红阳猕猴桃果浆干制品的还原型抗坏血酸保存率超过98%.此外,从理化指标(主要为抗坏血酸的保存率)与感官指标方面比较了冻干制品与热风干燥制品的差异,红阳猕猴桃果浆冻干加工制品的指标值均大大优于热风干制加工制品的指标值.

  17. A GIS analysis of the relationship between sinkholes, dry-well complaints and groundwater pumping for frost-freeze protection of winter strawberry production in Florida.

    Directory of Open Access Journals (Sweden)

    Mark D Aurit

    Full Text Available Florida is riddled with sinkholes due to its karst topography. Sometimes these sinkholes can cause extensive damage to infrastructure and homes. It has been suggested that agricultural practices, such as sprinkler irrigation methods used to protect crops, can increase the development of sinkholes, particularly when temperatures drop below freezing, causing groundwater levels to drop quickly during groundwater pumping. In the strawberry growing region, Dover/Plant City, Florida, the effects have caused water shortages resulting in dry-wells and ground subsidence through the development of sinkholes that can be costly to maintain and repair. In this study, we look at how frost-freeze events have affected West Central Florida over the past 25 years with detailed comparisons made between two cold-years (with severe frost-freeze events and a warm year (no frost-freeze events. We analyzed the spatial and temporal correlation between strawberry farming freeze protection practices and the development of sinkholes/dry well complaints, and assessed the economic impact of such events from a water management perspective by evaluating the cost of repairing and drilling new wells and how these compared with using alternative crop-protection methods. We found that the spatial distribution of sinkholes was non-random during both frost-freeze events. A strong correlation between sinkhole occurrence and water extraction and minimum temperatures was found. Furthermore as temperatures fall below 41°F and water levels decrease by more than 20 ft, the number of sinkholes increase greatly (N >10. At this time alternative protection methods such as freeze-cloth are cost prohibitive in comparison to repairing dry wells. In conclusion, the findings from this study are applicable in other agricultural areas and can be used to develop comprehensive water management plans in areas where the abstraction of large quantities of water occur.

  18. Dry process for economic cell manufacturing

    Science.gov (United States)

    Donon, J.; Lauvray, H.; Aubril, P.; David, G.; Loubly, P.

    Plasma dry etching technologies and screen printing processes for the dopant and the contacts were employed in an attempt to develop a completely dry process for solar cell manufacturing. Plasma etching within a barrel reactor produced etch rates of 0.3 and 0.6 micron/min, compared with acid etching rates of 13 microns/min and basic etching rates of 5 microns/min. Ring etching was also carried out in a barrel reactor with 200 wafers positioned in a stack, power levels of 850 W, a CF4 + 8 pct O2 plasma, a flow rate of 200 cc/min, and a run time of 15 min. The ring etching process was also tested and proven to have good reproducibility. A doping paste was employed, together with a thermal treatment at 850 C for 1 hr, to obtain good diffusion homogeneity. The results included cell efficiencies more than half those from chemical etching with both monocrystalline and polycrystalline materials. The techniques are concluded to produce negligible pollution, waste little material, and be amenable to automation.

  19. Application of the freeze-dried bioluminescent bioreporter Pseudomonas putida mt-2 KG1206 to the biomonitoring of groundwater samples from monitoring wells near gasoline leakage sites.

    Science.gov (United States)

    Ko, Kyung-Seok; Kong, In Chul

    2017-02-01

    This study examined the applicability of a freeze-dried bioluminescent bioreporter, Pseudomonas putida mt-2 KG1206 (called KG1206), to the biomonitoring of groundwater samples. Samples were collected from the monitoring wells of gas station tanks or old pipeline leakage sites in Korea. In general, the freeze-dried strain in the presence of pure inducer chemicals showed low bioluminescence activity and a different activity order compared with that of the subcultured strain. The effects of KNO3 as a bioluminescence stimulant were observed on the pure inducers and groundwater samples. The stimulation rates varied according to the type of inducers and samples, ranging from 2.2 to 20.5 times (for pure inducers) and from 1.1 to 11 times (for groundwater samples) the total bioluminescence of the control. No considerable correlations were observed between the bioluminescence intensity of the freeze-dried strain and the inducer concentrations in the samples (R (2) < 0.1344). However, samples without a high methyl tertiary butyl ether (MTBE) level and those from the gas station leakage site showed reasonable correlations with the bioluminescence activity with R (2) values of 0.3551 and 0.4131, respectively. These results highlight the potential of using freeze-dried bioluminescent bacteria as a rapid, simple, and portable tool for the preliminary biomonitoring of specific pollutants at contaminated sites.

  20. Microbial adhesion to surface-grafted polyacrylamide brushes after long-term exposure to PBS and reconstituted freeze-dried saliva

    NARCIS (Netherlands)

    Fundeanu, Irina; van der Mei, Henny C.; Schouten, Arend J.; Busscher, Henk J.

    2010-01-01

    Polyacrylamide (PAAm) brushes, covalently grafted from silicon wafer surfaces were examined for their ability to inhibit microbial adhesion after long-term exposure to PBS or reconstituted freeze-dried saliva for time intervals from 48 h up to 1 month at 37 degrees C. Microbial adhesion after

  1. Effects of protectant and rehydration conditions on the survival rate and malolactic fermentation efficiency of freeze-dried Lactobacillus plantarum JH287.

    Science.gov (United States)

    Lee, Sae-Byuk; Kim, Dong-Hwan; Park, Heui-Dong

    2016-09-01

    In this study, Lactobacillus plantarum JH287 was used as a malolactic fermentation starter in Campbell Early wine production. L. plantarum JH287 was first lyophilized, and the malolactic fermentation potential of freeze-dried L. plantarum JH287 was investigated. Different protective media and rehydration conditions were tested to improve the survival rate of freeze-dried L. plantarum JH287. Optimal protective medium contained 10 % sorbitol and 10 % skim milk. The optimal rehydration condition was a 1-h rehydration time conducted in the same protective media, and the combination of these two methods produced a survival rate of 86.37 %. In addition, a 77.71 % survival rate was achieved using freeze-dried samples that were stored at 4 °C for 2 months. Freeze-dried L. plantarum JH287 and Saccharomyces cerevisiae Fermivin were used to inoculate the Campbell Early grape must to decrease its malic acid content. Using this mixed-fermentation method, wine showed a decrease in malic acid content after 9 days of fermentation. GC-MS analysis detected 15 volatile ester compounds in the wine. A sensory evaluation showed that the taste and aroma of mix-fermented wine were better than those of the control that had not been inoculated with L. plantarum JH287.

  2. Impact of different cryoprotectants on the survival of freeze-dried Lactobacillus rhamnosus and Lactobacillus casei/paracasei during long-term storage.

    Science.gov (United States)

    Jofré, A; Aymerich, T; Garriga, M

    2015-01-01

    The production of long shelf-life highly concentrated dried probiotic/starter cultures is of paramount importance for the food industry. The aim of the present study was to evaluate the protective effect of glucose, lactose, trehalose, and skim milk applied alone or combined upon the survival of potentially probiotic Lactobacillus rhamnosus CTC1679, Lactobacillus casei/paracasei CTC1677 and L. casei/paracasei CTC1678 during freeze-drying and after 39 weeks of storage at 4 and 22 °C. Immediately after freeze-drying, the percentage of survivors was very high (≥ 94%) and only slight differences were observed among strains and cryoprotectants. In contrast, during storage, survival in the dried state depended on the cryoprotectant, temperature and strain. For all the protectants assayed, the stability of the cultures was remarkably higher when stored under refrigeration (4 °C). Under these conditions, skim milk alone or supplemented with trehalose or lactose showed the best performance (reductions ≤ 0.9 log units after 39 weeks of storage). The lowest survival was observed during non-refrigerated storage and with glucose and glucose plus milk; no viable cells left at the end of the storage period. Thus, freeze-drying in the presence of appropriate cryoprotectants allows the production of long shelf-life highly concentrated dried cultures ready for incorporation in high numbers into food products as starter/potential probiotic cultures.

  3. WEIGHT LOSS DETERMINATION OF LAMB CARCASSES DURING THE PRECOOLING AND FREEZING PROCESS

    Directory of Open Access Journals (Sweden)

    İbrahim YILMAZ

    1995-01-01

    Full Text Available Total weight loss of Morkaraman breed lamb carcasses were determined during the precooling and also during the freezing process of the carcasses. Research was carried out in the cooling and freezing rooms of Turkish State Slaughter House (EBK of Erzurum. Determined results were compared with the literature values given by different researches. Some suggestions were made to optimize the precooling and frozen process. In each trial, 64 lambs were selected randomly from different herds had been come to slaughter. After slaughter and dressing carcasses were showered with cold water, and removing the kidney and peripheral fats, the carcasses were used in precooling and freezing experiments. Precooling, freezing and all the other treatments were done in the practical handling conditions of EBK, that is none of those conditions were rearranged or altered, and what had been happening in those conditions were aimed to be determined. Experiment was repeated 7 times, thus total of 448 whole carcasses were used in the entire research work. At the end of this study, the average precooling and freezing weight losses were 1.88% and 1.3% respectively and their sum was 3.18%. It was determined that duration of precooling and freezing, average carcass weight, relative humidity, air circulation and loading percentage of the rooms were very effective on the weight losses.

  4. Heat Transfer Analysis of an Optimized, Flexible Holder System for Freeze-Drying in Dual Chamber Cartridges Using Different State-of-the-Art PAT Tools.

    Science.gov (United States)

    Korpus, Christoph; Pikal, Michael; Friess, Wolfgang

    2016-11-01

    The aim of this study was to determine the heat transfer characteristics of an optimized flexible holder device, using Tunable Diode Laser Absorption Spectroscopy, the Pressure Rise Test, and the gravimetric procedure. Two different controlled nucleation methods were tested, and an improved sublimation process, "preheated plate," was developed. Tunable Diode Laser Absorption Spectroscopy identified an initial sublimation burst phase. Accordingly, steady-state equations were adapted for the gravimetric procedure, to account for this initial non-steady-state period. The heat transfer coefficient, KDCC, describing the transfer from the holder to the DCC, was the only heat transfer coefficient showing a clear pressure dependence with values ranging from 3.81E-04 cal/(g·cm(2)·K) at 40 mTorr to 7.38E-04 cal/(g·cm(2)·K) at 200 mTorr. The heat transfer coefficient, Ktot, reflecting the overall energy transfer via the holder, increased by around 24% from 40 to 200 mTorr. This resulted in a pressure-independent sublimation rate of around 42 ± 1.06 mg/h over the whole pressure range. Hence, this pressure-dependent increase in energy transfer completely compensated the decrease in driving force of sublimation. The "flexible holder" shows a substantially reduced impact of atypical radiation, improved drying homogeneity, and ultimately a better transferability of the freeze-drying cycle for process optimization.

  5. OPTIMIZATION OF THE PROCESS OF DRYING THE FILTRATE DISTILLERY DREGS

    Directory of Open Access Journals (Sweden)

    A. A. Shevtsov

    2013-01-01

    Full Text Available The interactions of various factors affecting the process of drying the filtrate distillery dregs are investigated. Rational conditions for the process of drying the filtrate distillery dregs in a spray dryer are obtained.

  6. Nutritional, phytochemical and antioxidant evaluation and FT-IR analysis of freeze dried extracts of Ecballium elaterium fruit juice from three localities

    Directory of Open Access Journals (Sweden)

    Samir FELHI

    2016-01-01

    Full Text Available Abstract This study was designed to investigate chemical composition, the total phenolic content, flavonoid content, antioxidant activity and to analyze through FT-IR spectroscopy method the freeze-dried extract of Ecballium elaterium fruit from three different localities. The highest level of phenolic and flavonoid contents was recorded for the fruit juice from the Cap-Bon region, with 106.4 ± 0.4 mg GAE/g and 6.5 ± 0.2 mg QE/g, respectively. Antioxidant activity varied in dose-dependent manner with IC50 values for DPPH scavenging of the freeze-dried fruit juice extracts from Cap-Bon, Kef and Sidi Bouzid were 38.6 ± 0.2, 50.1 ± 0.7, and 50.7 ± 0.2 µg/mL, respectively. The results from the FRAP test showed that the freeze-dried extracts of Cap-Bon exhibited potent activity, followed by those from Kef and Sidi Bouzid. Similar trend were revealed for ABTS•+ test, with the fruit juice extract from Cap-Bon (IC50 = 0.6 ± 0.0 mg/mL. Furthermore, a good positive correlation was observed between the total phenols and three assays, especially DPPH. The freeze-dried extracts of fruit juice from Cap-Bon showed strong ability to act as antioxidants and can be considered as promising natural source of bioactive compounds. FT-IR analysis of each freeze-dried extract confirmed its richness on polyphenols and biological active functional groups.

  7. Raman spectroscopy and multivariate analysis for the rapid discrimination between native-like and non-native states in freeze-dried protein formulations.

    Science.gov (United States)

    Pieters, Sigrid; Vander Heyden, Yvan; Roger, Jean-Michel; D'Hondt, Matthias; Hansen, Laurent; Palagos, Bernard; De Spiegeleer, Bart; Remon, Jean-Paul; Vervaet, Chris; De Beer, Thomas

    2013-10-01

    This study investigates whether Raman spectroscopy combined with multivariate analysis (MVA) enables a rapid and direct differentiation between two classes of conformational states, i.e., native-like and non-native proteins, in freeze-dried formulations. A data set comprising of 99 spectra, both from native-like and various types of non-native freeze-dried protein formulations, was obtained by freeze-drying lactate dehydrogenase (LDH) as model protein under various conditions. Changes in the secondary structure in the solid freeze-dried proteins were determined through visual interpretation of the blank corrected second derivative amide I band in the ATR-FTIR spectra (further called FTIR spectra) and served as an independent reference to assign class labels. Exploratory analysis and supervised classification, using Principal Components Analysis (PCA) and Partial Least Squares - Linear Discriminant Analysis (PLS-LDA), respectively, revealed that Raman spectroscopy is with 95% accuracy able to correctly discriminate between native-like and non-native states in the tested freeze-dried LDH formulations. Backbone (i.e., amide III) and side chain sensitive spectral regions proved important for making the discrimination between both classes. As discrimination was not influenced by the spectral signals from the tested excipients, there was no need for blank corrections. The Raman model may allow direct and automated analysis of the investigated quality attribute, opening possibilities for a real time and in-line quality indication as a future step. However, the sensitivity of the method should be further investigated and where possible improved. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. 9 CFR 590.542 - Spray process drying operations.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Spray process drying operations. 590..., Processing, and Facility Requirements § 590.542 Spray process drying operations. (a) The drying room shall be... interrupted. (1) Spray nozzles, orifices, cores, or whizzers shall be cleaned immediately after cessation...

  9. Encapsulation of lycopene using spray-drying and molecular inclusion processes

    Directory of Open Access Journals (Sweden)

    Itaciara Larroza Nunes

    2007-09-01

    Full Text Available This study aimed to obtain encapsulated lycopene in a powder form, using either spray-drying or molecular inclusion with beta -cyclodextrin ( beta -CD followed by freeze-drying. The encapsulation efficiency using spray-drying ranged from 94 to 96%, with an average yield of 51%, with microcapsules showing superficial indentations and lack of cracks and breakages. Lycopene- beta -CD complexes were only formed at a molar ratio of 1:4, and irregular structures of different sizes that eventually formed aggregates, similar to those of beta -CD, were observed after freeze-drying. About 50% of the initial lycopene did not form complexes with beta -CD. Lycopene purity increased from 96.4 to 98.1% after spray-drying, whereas lycopene purity decreased from 97.7 to 91.3% after complex formation and freeze-drying. Both the drying processes yielded pale-pink, dry, free-flowing powders.Técnicas de encapsulamento, como "spray-drying" e formação de complexos por inclusão com ciclodextrinas, vêm sendo avaliadas para viabilizar a adição de carotenóides em sistemas hidrofílicos e aumentar a sua estabilidade durante o processamento e estocagem. Portanto, o objetivo do presente trabalho foi obter licopeno encapsulado na forma de pó, utilizando processos de "spray-drying" ou de inclusão molecular com beta -ciclodextrina (CD seguido de liofilização. A eficiência do encapsulamento utilizando "spray-drying" variou de 94 a 96% e o rendimento médio foi de 51%, com as microcápsulas apresentando indentações superficiais, porém sem falhas ou aberturas na superfície. A formação de complexo licopeno- beta -CD ocorreu apenas quando utilizada razão molar de 1:4, e estruturas irregulares de diferentes tamanhos que eventualmente formaram agregados, similares às da beta -CD, foram observadas após liofilização. O licopeno não complexado neste processo ficou em torno de 50%. A pureza do licopeno (% área do all-trans-licopeno aumentou de 96,4 para 98,1% ap

  10. Generalized enthalpy model of a high-pressure shift freezing process

    KAUST Repository

    Smith, N. A. S.

    2012-05-02

    High-pressure freezing processes are a novel emerging technology in food processing, offering significant improvements to the quality of frozen foods. To be able to simulate plateau times and thermal history under different conditions, in this work, we present a generalized enthalpy model of the high-pressure shift freezing process. The model includes the effects of pressure on conservation of enthalpy and incorporates the freezing point depression of non-dilute food samples. In addition, the significant heat-transfer effects of convection in the pressurizing medium are accounted for by solving the two-dimensional Navier-Stokes equations. We run the model for several numerical tests where the food sample is agar gel, and find good agreement with experimental data from the literature. © 2012 The Royal Society.

  11. Thawing and freezing processes of active layer in Wudaoliang region of Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The interaction between permafrost and atmosphere is accomplished through transfer of heat and moisture in the overlay active layer. Thus, the research on the thermal and hydro- dynamics of active layer during the thawing and freezing processes was considered a key to revealing the heat and moisture exchanges between permafrost and atmosphere. The monitoring and research on active layer were conducted because permafrost occupies about two thirds of the total area of the Tibetan Plateau. Based on the analysis of the ground temperature data and soil moisture data of monitoring near the Wudaoliang region of the Tibetan Plateau, the thawing and freezing processes of active layer were divided into four stages, i.e. summer thawing stage (ST), autumn freezing stage (AF), winter cooling stage (WC) and spring warming stage (SW). Coupled heat and water flow is much more complicated in ST and AF, and more amount of water is migrating in these two stages. Heat is transferred mainly via conductive heat flow in the other two stages, and less water migrated. Four water migration and coupled heat flow processes were addressed for the thawing and freezing stages, which are water infiltration driven by gravity, moisture advection and distillation driven by temperature and osmotic gradients, water migration driven by capillarity and unfrozen water migration driven by temperature gradient. The water content near the permafrost table tends to increase after one thawing and freezing cycle, which is the main reason for the development of thick ground ice layer near permafrost table.

  12. Particle removal process during application of impinging dry ice jet

    OpenAIRE

    Liu, Yi-Hung; Hirama, Daisuke; Matsusaka, Shuji

    2012-01-01

    In this study, we have investigated the application of dry ice blasting to remove fine particles adhering to surfaces and examined the removal process. The removal efficiency, area, and frequency have been analyzed using images captured with a high-speed microscope camera. In addition, the temperature of the dry ice jet has been measured in order to evaluate the dry ice particles and their effects on the particle removal process. The removal processes due to the impacts of primary dry ice par...

  13. Fabric-drying process in domestic dryers

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, V.; Moon, C.G. [Department of Mechanical Engineering, The University of Auckland, Auckland 1142 (New Zealand)

    2008-02-15

    A theoretical analysis of the drying process occurring inside the household electric tumbler clothes-dryer is performed to determine various thermo-physical parameters affecting the energy consumption and for the development of a simulation model. Experiments are conducted on a test set-up, based on a compact tumble-dryer, to measure the values of the parameters necessary for evaluating the performance. Widely-accepted economy standards are considered for comparison of simulation and experimental results. The simulation results are in reasonable agreement with experimental data. An empirical correlation for the specific moisture-extraction rate (SMER) is developed to translate energy-consumption information from one standard to the other. (author)

  14. The use of 90% Aloe vera freeze drying as the modulator of collagen density in extraction socket of incicivus Cavia cobaya

    Directory of Open Access Journals (Sweden)

    Ester Arijani

    2008-06-01

    Full Text Available Wound healing is basically a complex process in which cellular and matrix act in concern to re-establish the integrity of injury tissues. This process can be simplified to be healing process consisted of haemostatic, inflammation, cell proliferation and tissue remodeling. The aimed of this research was to know the influence of freeze drying 90% Aloe vera application as mandible collagen density modulator in extraction socket of incisive Cavia cobaya. This research was done using Post Test Only Control Groups Design and Cavia cobaya as the sample. Six samples of each control group and 90% Aloe vera group applied to test each collagen density for three days and seven days. Then, the data was analyzed statistically using Mann Whitney with 5% significance rate. The result of the study indicates that administering 90% Aloe vera can accelerate the growth of collagen density in healing process of extraction socket. The conclusion is 90% Aloe vera can modulate the density of collageneous fiber in socket of extraction incicivus tooth wound of Cavia cobaya.

  15. Breads Fortified with Freeze-Dried Vegetables: Quality and Nutritional Attributes. Part II: Breads Not Containing Oil as an Ingredient

    Directory of Open Access Journals (Sweden)

    Viren Ranawana

    2016-09-01

    Full Text Available The present article describes the second part of a study investigating the effect of adding vegetables on the nutritional, physico-chemical, and oxidative properties of wheat bread, and specifically focuses on bread that does not contain oil as an added ingredient. Wheat flour breads fortified with freeze-dried carrot, tomato, beetroot or broccoli were developed and assessed for their nutritional composition, antioxidant potential, oxidative stability, and storage properties. Using a simulated in vitro model, the study also examined the impact of vegetable addition on the oxidative stability of macronutrients during gastro-intestinal digestion. Adding vegetables improved the nutritional and functional attributes of the oil-free breads. However, they demonstrated a lower antioxidant potential compared to their oil-containing counterparts. Similarly, the textural and storage properties of the oil-free vegetable breads were poorer compared to the oil-containing breads. As expected, in the absence of oil the oil-free breads were associated with lower lipid oxidation both in their fresh form and during gastro-intestinal digestion. Adding vegetables reduced protein oxidation in the fresh oil-free breads but had no effect during gastro-intestinal digestion. The impact of vegetables on macronutrient oxidation in the oil-free breads during digestion appears to be vegetable-specific with broccoli exacerbating it and the others having no effect. Of the evaluated vegetables, beetroot showed the most promising nutritional and physico-chemical benefits when incorporated into bread that does not contain added oil.

  16. Freeze-dried mucoadhesive polymeric system containing pegylated lipoplexes: Towards a vaginal sustained released system for siRNA.

    Science.gov (United States)

    Furst, Tania; Dakwar, George R; Zagato, Elisa; Lechanteur, Anna; Remaut, Katrien; Evrard, Brigitte; Braeckmans, Kevin; Piel, Geraldine

    2016-08-28

    Topical vaginal sustained delivery of siRNA presents a significant challenge due to the short residence time of formulations. Therefore, a drug delivery system capable to adhere to the vaginal mucosa is desirable, as it could allow a prolonged delivery and increase the effectiveness of the therapy. The aim of this project is to develop a polymeric solid mucoadhesive system, loaded with lipoplexes, able to be progressively rehydrated by the vaginal fluids to form a hydrogel and to deliver siRNA to vaginal tissues. To minimize adhesive interactions with vaginal mucus components, lipoplexes were coated with different derivatives of polyethylene glycol: DPSE-PEG2000, DPSE-PEG750 and ceramide-PEG2000. Based on stability and diffusion properties in simulated vaginal fluids, lipoplexes containing DSPE-PEG2000 were selected and incorporated in hydroxyethyl cellulose (HEC) hydrogels. Solid systems, called sponges, were then obtained by freeze-drying. Sponges meet acceptable mechanical characteristics and their hardness, deformability and mucoadhesive properties are not influenced by the presence of lipoplexes. Finally, mobility and stability of lipoplexes inside sponges rehydrated with vaginal mucus, mimicking in situ conditions, were evaluated by advanced fluorescence microscopy. The release rate was found to be influenced by the HEC concentration and consequently by the viscosity after rehydration. This study demonstrates the feasibility of entrapping pegylated lipoplexes into a solid matrix system for a prolonged delivery of siRNA into the vagina.

  17. Tertiary combination of freeze-dried urine of Indian breeds of cow with plant products against snail Lymnaea acuminata.

    Science.gov (United States)

    Kumar, Shiv; Singh, D K; Singh, Vinay Kumar

    2012-10-15

    Snail Lymnaea acuminata is the intermediate host of liver fluke Fasciola gigantica, which cause endemic fasciolosis among cattle population of eastern Uttar Pradesh. Control of snail population by molluscicides is one of the effective methods to control fasciolosis. In the present study molluscicidal activity of tertiary combination of freeze-dried urine of different Indian breeds of cow Sahiwal, Geer and Tharparkar with Annona squamosa seed powder, Ferula asafoetida root latex, Azadirachta indica oil and Camellia sinensis leaves have been tested against Lymnaea acuminata. It was noted that the toxicity of tertiary combination (1:1:5) of cow urine kept for 15 days in sunlight or laboratory condition with different plant products were highly toxic against snail L. acuminata. 96 h LC50 of tertiary combinations with Sahiwal urine kept for 15 days in sunlight with A. squamosa, F. asafoetida, A. indica oil and C. sinensis were 35.47 mg L(-1), 37.13 mg L(-1), 33.66 mg L(-1), respectively higher than the Geer and Tharparkar. The toxicity of Sahiwal urine kept for 15 days in laboratory condition with A. squamosa and C. sinensis (96 h LC50 28.28 mg L(-1)) was more potent than the all other combinations. Cow urine in combination with plant product can be used for effective control of snail.

  18. {sup 68}Ga Labeling of DOTMP using Freeze-dried Kit for the Imaging of Bone Metastasis

    Energy Technology Data Exchange (ETDEWEB)

    Dho, So Hee; Choi, Sangmu; Kim, Sooyong; Cho, Eunha; Lee, Soyoung; Jung, Sunghee; Lim, Jaecheong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Bone is a favorable site of metastasis and is invaded common primary tumors such as prostate, breast, and lung. Due to the progressive pain and mortality of the bone metastasis, effort has been focused on the detection of bone metastasis in the field of nuclear medicine (Mitterhauser, Toegel et al. 2007, Mirzaei, Jalilian et al. 2015). In designing suitable imaging agents for bone metastasis, multidentate polyaminophosphonate are regarded as the most promising candidates as carrier ligands owing to their high bone affinity, selective localization in skeletal lesions and ability to form metal chelates with high in-vivo stability (Chakraborty, Das et al. 2008). 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene. Freeze-dried DOTMP kit vial was consist of 400 μ of DOTMP, 19.27 mg of ammonium acetate and 17.62 mg of ascorbic acid. All the preparative steps were carried out under aseptic conditions, and the prepared kit vials were shown in Fig. 3(A). The easy and efficient labeling of this kit with 68Ga make them suitable for preparing 68Ga-DOTMP for imaging of bone metastasis.

  19. Freeze Dried Quetiapine-Nicotinamide Binary Solid Dispersions: A New Strategy for Improving Physicochemical Properties and Ex Vivo Diffusion

    Science.gov (United States)

    Al-Remawi, Mayyas Mohammad Ahmad

    2016-01-01

    Improving the physicochemical properties and oral bioavailability of quetiapine fumarate (QF) enabling enhanced antipsychotic attributes are the main aims of this research. The freeze dried solid dispersion strategy was adopted using nicotinamide (NIC) as highly soluble coformer. The prepared dispersions were characterized using scanning electron microscopy (SEM) differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Static disc intrinsic dissolution rate and ex vivo diffusion through intestinal tissues were conducted and compared to pure quetiapine fumarate. The results demonstrated a highly soluble coamorphous system formed between quetiapine fumarate and nicotinamide at 1 : 3 molar ratio through H-bonding interactions. The results showed >14-fold increase in solubility of QF from the prepared dispersions. Increased intrinsic dissolution rate (from 0.28 to 0.603 mg cm−2 min−1) and faster flux rate through duodenum (from 0.027 to 0.041 mg cm−2 h−1) and jejunum (0.027 to 0.036 mg cm−2 h−1) were obtained. The prepared coamorphous dispersion proved to be effective in improving the drug solubility and dissolution rate and ex vivo diffusion. Therefore, binary coamorphous dispersions could be a promising solution to modify the physicochemical properties, raise oral bioavailability, and change the biopharmaceutics classification (BCS) of some active pharmaceutical ingredients. PMID:28042494

  20. Evaluation of protective effect of freeze-dried strawberry, grape, and blueberry powder on acrylamide toxicity in mice.

    Science.gov (United States)

    Zhao, Mengyao; Liu, Xin; Luo, Yinghua; Guo, Huan; Hu, Xiaosong; Chen, Fang

    2015-04-01

    Berries are dietary plants with high antioxidant activity. The aim of this study is to investigate the protective effect of berries (strawberry, grape, and blueberry) against the acrylamide (AA)-induced general toxicity, genotoxicity, and reproductive toxicity in mice model, respectively. Mice were treated with 50 mg/kg b.w./day AA intraperitoneal injection for 5 d after feeding control diet or diet containing freeze-dried strawberry, grape, and blueberry powder. The results showed that AA induced a significant general toxicity, genotoxicity, and reproductive toxicity in mice. Compared with the control diet, the diets containing berries could reverse the AA-induced alterations in liver antioxidant enzymes activities (P < 0.05). Moreover, the AA-induced genotoxicity could be prevented by the diet containing berries. The DNA damage in the lymphocyte and liver cells and the micronucleus formation in bone marrow cell were significantly alleviated (P < 0.05). Meanwhile, the mice fed with diets containing berries showed a recovery in the sperm count, the sperm activity rate, sperm motility parameters, and the abnormal sperm rate (P < 0.05). Berry powders have remarkable intervention against the AA-induced general toxicity, genotoxicity, reproductive toxicity. Abundant phenolics, especially anthocyanins, may contribute to the intervention.

  1. Immunomodulatory effects of supercritical fluid CO2 extracts from freeze-dried powder of Tenebrio molitor larvae (yellow mealworm

    Directory of Open Access Journals (Sweden)

    QingFeng TANG

    2016-01-01

    Full Text Available Abstract In order to take full advantage of Tenebrio molitor larvae (yellow mealworm resources, the supercritical CO2 fluid freeze-dried powder of T. molitor larvae (fdTML extraction on the immune systems of mice was carried out. The results about the effects of supercritical CO2 fluid fdTML extraction on carbon expurgation and phagocytosis of peritoneal macrophages experiments of mice indicated that the fdTML extraction enhanced observably carbon expurgatory index, phagocytic rate and phagocytic index. The fdTML extraction could stimulate response of delayed hypersensitivity. The proliferation of ConA-induced mitogenic reponse for spleen lymphocyte was also increased. The amount of hemolytic antibody in mice serum increased compared with those of the control group mice. The half of hemolysis values in serum of treated mice increased compared to the control group. Furthermore, serum NO content in all treatment groups was higher than that of the control group whereas acid phosphatase and alkaline phosphatase activity was only significantly higher relative to the control group. Our findings suggest that supercritical CO2 fluid the fdTML extraction has potential as a health food supplement.

  2. The intrinsically disordered protein LEA7 from Arabidopsis thaliana protects the isolated enzyme lactate dehydrogenase and enzymes in a soluble leaf proteome during freezing and drying.

    Science.gov (United States)

    Popova, Antoaneta V; Rausch, Saskia; Hundertmark, Michaela; Gibon, Yves; Hincha, Dirk K

    2015-10-01

    The accumulation of Late Embryogenesis Abundant (LEA) proteins in plants is associated with tolerance against stresses such as freezing and desiccation. Two main functions have been attributed to LEA proteins: membrane stabilization and enzyme protection. We have hypothesized previously that LEA7 from Arabidopsis thaliana may stabilize membranes because it interacts with liposomes in the dry state. Here we show that LEA7, contrary to this expectation, did not stabilize liposomes during drying and rehydration. Instead, it partially preserved the activity of the enzyme lactate dehydrogenase (LDH) during drying and freezing. Fourier-transform infrared (FTIR) spectroscopy showed no evidence of aggregation of LDH in the dry or rehydrated state under conditions that lead to complete loss of activity. To approximate the complex influence of intracellular conditions on the protective effects of a LEA protein in a convenient in-vitro assay, we measured the activity of two Arabidopsis enzymes (glucose-6-P dehydrogenase and ADP-glucose pyrophosphorylase) in total soluble leaf protein extract (Arabidopsis soluble proteome, ASP) after drying and rehydration or freezing and thawing. LEA7 partially preserved the activity of both enzymes under these conditions, suggesting its role as an enzyme protectant in vivo. Further FTIR analyses indicated the partial reversibility of protein aggregation in the dry ASP during rehydration. Similarly, aggregation in the dry ASP was strongly reduced by LEA7. In addition, mixtures of LEA7 with sucrose or verbascose reduced aggregation more than the single additives, presumably through the effects of the protein on the H-bonding network of the sugar glasses.

  3. Product mass transfer resistance directly determined during freeze-drying cycle runs using tunable diode laser absorption spectroscopy (TDLAS) and pore diffusion model.

    Science.gov (United States)

    Kuu, Wei Y; O'Bryan, Kevin R; Hardwick, Lisa M; Paul, Timothy W

    2011-08-01

    The pore diffusion model is used to express the dry layer mass transfer resistance, [Formula: see text], as a function of the ratio r(e)/?, where r(e) is the effective pore radius and ? is the tortuosity factor of the dry layer. Using this model, the effective pore radius of the dry layer can be estimated from the sublimation rate and product temperature profiles measured during primary drying. Freeze-drying cycle runs were performed using the LyoStar II dryer (FTS Systems), with real-time sublimation rate profiles during freeze drying continuously measured by tunable diode laser absorption spectroscopy (TDLAS). The formulations chosen for demonstration of the proposed approach include 5% mannitol, 5% sucrose, 5% lactose, 3% mannitol plus 2% sucrose, and a parenteral nutrition formulation denoted VitaM12. The three different methods used for determination of the product resistance are: (1) Using both the sublimation rate and product temperature profiles, (2) using the sublimation rate profile alone, and (3) using the product temperate profile alone. Unlike the second and third methods, the computation procedure of first method does not need solution of the complex heat and mass transfer equations.

  4. Freeze Drying Technology of Lost Foam Casting Pattern%消失模模样的冷冻干燥技术

    Institute of Scientific and Technical Information of China (English)

    杨先锋

    2011-01-01

    The drying mechanism of lost foam casting pattern was discussed, and a freeze drying technology was presented, which is different with the traditional drying method, and is suitable for use in the drying room of medium-small foundry. Comparing with the traditional drying method, this technology not only has advantages of less investment, safety, automatic control and simple maintenance, but also gets a breakthrough in both of labor protection and energy saving, which is the most .important. The production practices show that the freeze drying technology can be applied to the foundry industry.%论述了消失模铸造生产中模样干燥的机理,介绍了一种不同于传统烘干干燥,适合用在中小铸造车间干燥室的冷冻干燥技术.生产实践结果表明,冷冻除湿干燥技术与传统的干燥技术相比,不仅具备投资少、生产安全、自动控制和维护简单的特点,更重要的是在劳动保护和节能降耗两方面取得了突破性的进步,具有在在铸造行业推广应用的价值.

  5. Experimental Investigation of Effectiveness of Magnetic Field on Food Freezing Process

    Science.gov (United States)

    Suzuki, Toru; Takeuchi, Yuri; Masuda, Kazunori; Watanabe, Manabu; Shirakashi, Ryo; Fukuda, Yutaka; Tsuruta, Takaharu; Yamamoto, Kazutaka; Koga, Nobumitsu; Hiruma, Naoya; Ichioka, Jun; Takai, Kiyoshi

    Recently, several food refrigeration equipments that utilize magnetic field have attracted much attention from food production companies, consumers and mass media. However, the effectiveness of the freezers is not scientifically examined. Therefore, the effectiveness should be clarified by experiments or theoretical considerations. In this study, the effect of weak magnetic field (about 0.0005 T) on freezing process of several kinds of foods was investigated by using a specially designed freezer facilitated with magnetic field generator. The investigation included the comparison of freezing curves, drip amount, physicochemical evaluations on color and texture, observation of microstructure, and sensory evaluation. From the results of the control experiments, it can be concluded that weak magnetic field around 0.0005 T provided no significant difference on temperature history during freezing and on the qualities of frozen foods, within our experimental conditions.

  6. 喷雾冷冻干燥对颗粒产品形态的影响%Morphology of particle produced by spray-freeze drying

    Institute of Scientific and Technical Information of China (English)

    徐庆; 耿县如; 李占勇

    2013-01-01

    喷雾冷冻干燥作为一种新型颗粒制备技术,产品具有尺寸可控、多孔、速溶、流动性好等优点.鉴于该技术在医药、食品、化工等行业生产独特产品的优势,本文综述了国内外喷雾冷冻干燥过程中有关颗粒形成及其形态变化的影响因素,具体介绍了其冻结过程对蛋白质颗粒形态、脂质体颗粒稳定性、疫苗颗粒、无机材料形态等产品的影响.同时还指出了喷雾冷冻干燥技术存在过程不连续、规模化程度不高、低温液体处理不便等问题需要解决,表明合理优化喷雾冷冻干燥工艺及强化干燥过程将是该技术未来研究的重点.%Spray Freeze Drying (SFD) is a novel engineering technology for production of size-controlled, porous, instant-solubility, good-flowability powders. SFD has advantages in the production of specific particles especially in pharmaceutical, food, and chemical industries, the recent developments in SFD have been reviewed in this paper. Particle formation and morphology characteristics resulting from the steps of SFD process were discussed. The effects of freezing on the products of protein, liposome, vaccine particles, inorganic materials were also included in the discussion. SFD disadvantages, such as discontinuity, time-consuming and inconvenient handing of cryogenic liquids, were mentioned. Finally, optimization of the SFD process and drying intensification were pointed out as the future research directions.

  7. Evaluation of shrinkage temperature of bovine pericardium tissue for bioprosthetic heart valve application by differential scanning calorimetry and freeze-drying microscopy

    Directory of Open Access Journals (Sweden)

    Virgilio Tattini Jr

    2007-03-01

    Full Text Available Bovine pericardium bioprosthesis has become a commonly accepted device for heart valve replacement. Present practice relies on the measurement of shrinkage temperature, observed as a dramatic shortening of tissue length. Several reports in the last decade have utilized differential scanning calorimetry (DSC as an alternative method to determine the shrinkage temperature, which is accompanied by the absorption of heat, giving rise to an endothermic peak over the shrinkage temperature range of biological tissues. Usually, freeze-drying microscope is used to determine collapse temperature during the lyophilization of solutions. On this experiment we used this technique to study the shrinkage event. The aim of this work was to compare the results of shrinkage temperature obtained by DSC with the results obtained by freeze-drying microscopy. The results showed that both techniques provided excellent sensitivity and reproducibility, and gave information on the thermal shrinkage transition via the thermodynamical parameters inherent of each method.

  8. Gluten-free bread with an addition of freeze-dried red and purple potatoes as a source of phenolic compounds in gluten-free diet.

    Science.gov (United States)

    Gumul, Dorota; Ziobro, Rafał; Ivanišová, Eva; Korus, Anna; Árvay, Július; Tóth, Tomáš

    2017-02-01

    The basis for gluten-free diet is often gluten-free bread, which is usually characterized by a low-nutritional value, and lacks any pro-health properties. Only after an introduction of gluten-free raw materials, containing high level of bioactive compounds it would be possible to obtain the product with a pro-health potential. The aim of the study was to analyze the content of bioactive compounds (total phenolic content, phenolic acids, flavonoids, flavonols, anthocyanins and carotenoids) in gluten-free bread prepared with 5% addition of freeze-dried red and purple potatoes as well as to assess their antioxidant potential. Summarizing, among the analyzed gluten-free breads with an addition of freeze-dried red and purple potatoes, the best results could be obtained by using variety Magenta Love (red potato), which provided the highest levels of phenolic compounds and carotenoids and also antioxidant and antiradical activity.

  9. Investigation on the Mechanical Properties of a Cement-Based Material Containing Carbon Nanotube under Drying and Freeze-Thaw Conditions

    Directory of Open Access Journals (Sweden)

    Wei-Wen Li

    2015-12-01

    Full Text Available This paper aimed to explore the mechanical properties of a cement-based material with carbon nanotube (CNT under drying and freeze-thaw environments. Mercury Intrusion Porosimetry and Scanning Electron Microscopy were used to analyze the pore structure and microstructure of CNT/cement composite, respectively. The experimental results showed that multi-walled CNT (MWCNT could improve to different degrees the mechanical properties (compressive and flexural strengths and physical performances (shrinkage and water loss of cement-based materials under drying and freeze-thaw conditions. This paper also demonstrated that MWCNT could interconnect hydration products to enhance the performance of anti-microcracks for cement-based materials, as well as the density of materials due to CNT’s filling action.

  10. Effect of NaHCO3, MgSO4, Sodium Ascorbate, Sodium Glutamate, Phosphate Buffer on Survival of Lactobacillus bulgaricus During Freeze-drying

    Directory of Open Access Journals (Sweden)

    He Chen

    2013-06-01

    Full Text Available In the present study, the experiments were investigated the effects of different concentrations of cryoprotective agents, such as NaHCO3, MgSO4, sodium ascorbate, sodium glutamate, phosphate buffer, respectively, which used on survival of Lactobacillus bulgaricus during freeze drying. The number of viable cells and survival ratio were measured by the plate count method. The results were as follows: cryoprotective agents played important roles in survival of Lactobacillus bulgaricus during freeze drying. When the relative volume of phosphate buffer was 1.5 (v/v, the number of viable cells was highest, while the survival ratio reached highest, the concentration of sodium ascorbate was 4.5%.

  11. The use of skimmed dried milk as an alternative diluent for the cooling step during the boar sêmen freezing procedure

    Directory of Open Access Journals (Sweden)

    Tatyane Bandeira Barros

    2015-07-01

    Full Text Available One of the critical points in the cryopreservation process is the use of a proper diluent while lowering the temperature following the resuspension and thawing processes. Here, we tested an alternative diluent for the process of freezing boar semen. We used skimmed dried milk (SDM during the cooling and post-thawed resuspension steps. To do so, we collected semen from 15 Dalland boars using the glovedhand technique, and incubated each ejaculate sample at 30 °C. We then removed two semen aliquots from a pre-dilution. We diluted one of the aliquots in Beltsville thawing solution (BTS - control, and the remaining sample was diluted in SDM. Both aliquots were subsequently held at 30º C for 45 min (1st period of stabilization. At the end of this period, we analysed vigor and motility to determine sperm metabolic activity. We then held the diluted semen at 25° C for 30 min (2nd period of stabilization and at 17° C for 2 h (3rd period stabilization. We centrifuged the semen at 800 × g and 1600 × g at 5º C for 15 min, discarded the supernatant, and resuspended the sperm pellet in 2 mL of the cooling diluent at 5° C for 1h. We again diluted the samples in 2 mL of the freezing diluent, poured them into straws, and cooled and plunged them into liquid N2. The sêmen samples were thawed in a 39º C water bath, and were resuspended in their respective diluents at the same temperature. We determined the following sperm features: vigor, motility, vitality, acrosomal integrity and membrane functionality. During the first phase of temperature cooling (30º C, semen diluted in SDM exhibited a higher vigor (3.4 ± 0.6 and motility (78.6 ± 13.0 than those diluted BTS (vigor: 3.1 ± 0.7; motility: 69.4±14.3. However, after the thawing procedure, the inverse was observed in that: BTS samples exhibited a higher vigor (2.1 ± 0.6 and motility (35.5 ± 21.0 than SDM samples (vigor: 1.7 ± 0.9; motility: 22.8 ± 18.1. Regarding membrane functionality and

  12. Application of pulse combustion technology in spray drying process

    Directory of Open Access Journals (Sweden)

    I. Zbicinski

    2000-12-01

    Full Text Available The paper presents development of valved pulse combustor designed for application in drying process and drying tests performed in a specially built installation. Laser technique was applied to investigate the flow field and structure of dispersed phase during pulse combustion spray drying process. PDA technique was used to determine initial atomization parameters as well as particle size distribution, velocity of the particles, mass concentration of liquid phase in the cross section of spray stream, etc., in the drying chamber during drying tests. Water was used to estimate the level of evaporation and 5 and 10% solutions of sodium chloride to carry out drying tests. The Computational Fluid Dynamics technique was used to perform theoretical predictions of time-dependent velocity, temperature distribution and particle trajectories in the drying chamber. Satisfactory agreement between calculations and experimental results was found in certain regions of the drying chamber.

  13. Freeze-drying synthesis of an amorphous Zn(2+) complex and its transformation to a 2-D coordination framework in the solid state.

    Science.gov (United States)

    Itakura, T; Horike, S; Inukai, M; Kitagawa, S

    2016-03-14

    An amorphous and metastable precursor for a Zn two-dimensional coordination framework was synthesised via freeze drying. The precursor comprises randomly packed discrete clusters of a Zn complex. The amorphous-to-crystalline framework transformation, which was triggered by the gentle application of heat or pressure, was accompanied by a change in the coordination geometry of the Zn(2+) ions from tetrahedral to octahedral symmetry.

  14. Composition of w-3 and w-6 fatty acids in freeze-dried chicken embryo eggs with different days of development

    Directory of Open Access Journals (Sweden)

    Campos Célia Maria Teixeira de

    2004-01-01

    Full Text Available Fatty acids omega--3 and omega--6 composition and specially DHA were determined in freeze-dried chicken embryo eggs with pre-determined incubation periods. Fertile and embryo eggs presented palmitic (23.18 + 0.54%, stearic (7.70 + 0.28%, palmitoleic (3.00 + 0.19%, oleic (36.28 + 0.58%, linoleic (22.18 + 0.34%, linolenic (1.08 + 0.04%, arachidonic (2.04 + 0.03%, docosahexaenoic (0.91 + 0.03%, total omega-3 acids (2.26 + 0.10% and total omega-6 acids (24.62 + 0.33%. There were no significant differences in total contents of omega-3 fatty acids (p=0.1226 between freeze-dried chicken embryo eggs with different incubation periods (3, 5, 7, 9, and 11 days and fertile freeze-dried chicken eggs (day 0. However, there were significant differences in total medium contents of omega-6 fatty acids (p=0.0001. There was also a strong statistical evidence that quadratic model was related with expected values of DHA content (p= 0.0013.

  15. Multifrequency EPR study on freeze-dried fruits before and after X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, N.D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)]. E-mail: ndyepr@bas.bg; Aleksieva, K. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Dimitrova, A. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Georgieva, L. [Institute of Cryobiology and Food Technologies, 1162 Sofia (Bulgaria); Tzvetkova, E. [Institute of Cryobiology and Food Technologies, 1162 Sofia (Bulgaria)

    2006-09-15

    X-, K- and Q-band EPR studies on lyophilized whole pulp parts of blue plum, apricot, peach, melon as well as achens and pulp separately of strawberry before and after X-ray irradiation are reported. Before irradiation all samples show in X band a weak singlet EPR line with g=2.0030+/-0.0005, except melon, which is EPR silent. Immediately after irradiation all samples exhibit complex fruit-depending spectra, which decay with time and change to give, in ca. 50days, an asymmetric singlet EPR line with g=2.0041+/-0.0005. Only apricot pulp gave a typical ''sugar-like'' EPR spectrum. Singlet EPR lines recorded after irradiation in X -band are K- and Q-band resolved as typical anisotropic EPR spectra with g{sub ||}=2.0023+/-0.0003 and g{sub -}bar =2.0041+/-0.0005. In addition, K- and Q-band EPR spectra of all samples show a superposition with the six EPR lines of Mn{sup 2+} naturally present in the fruits. The saturation behavior of the EPR spectra of achens of lyophilized and fresh strawberry is also studied. The differences in g factors of samples before and after X-ray irradiation might be used for the identification of radiation processing of fruits in the case of pulp and the differences in the EPR saturation behavior might be used for the achens of strawberry.

  16. Structure-property-processing correlations in freeze-cast composite scaffolds.

    Science.gov (United States)

    Hunger, Philipp M; Donius, Amalie E; Wegst, Ulrike G K

    2013-05-01

    Surprisingly few reports have been published, to date, on the structure-property-processing correlations observed in freeze-cast materials directionally solidified from polymer solutions, or ceramic or metal slurries. The studies that exist focus on properties of sintered ceramics, that is materials whose structure was altered by further processing. In this contribution, we report first results on correlations observed in alumina-chitosan-gelatin composites, which were chosen as a model system to test and compare the effect of particle size and processing parameters on their mechanical properties at a specific composition. Our study reveals that highly porous (>90%) hybrid materials can be manufactured by freeze casting, through the self-assembly of a polymer and a ceramic phase that occurs during directional solidification, without the need of additional processing steps such as sintering or infiltration. It further illustrates that the properties of freeze-cast hybrid materials can independently be tailored at two levels of their structural hierarchy, allowing for the simultaneous optimization of both mechanical and structural requirements. An increase in freezing rate resulted in decreases in lamellar spacing, cell wall thickness, pore aspect ratio and cross-sectional area, as well as increases in both Young's modulus and compressive yield strength. The mechanical properties of the composite scaffolds increased with an increasing particle size. The results show that both structure and mechanical properties of the freeze-cast composites can be custom-designed and that they are thus ideally suited for a large variety of applications that require high porosity at low or medium load-bearing capacity.

  17. Discretisation of the non-linear heat transfer equation for food freezing processes using orthogonal collocation on finite elements

    Directory of Open Access Journals (Sweden)

    E. D. Resende

    2007-09-01

    Full Text Available The freezing process is considered as a propagation problem and mathematically classified as an "initial value problem." The mathematical formulation involves a complex situation of heat transfer with simultaneous changes of phase and abrupt variation in thermal properties. The objective of the present work is to solve the non-linear heat transfer equation for food freezing processes using orthogonal collocation on finite elements. This technique has not yet been applied to freezing processes and represents an alternative numerical approach in this area. The results obtained confirmed the good capability of the numerical method, which allows the simulation of the freezing process in approximately one minute of computer time, qualifying its application in a mathematical optimising procedure. The influence of the latent heat released during the crystallisation phenomena was identified by the significant increase in heat load in the early stages of the freezing process.

  18. Through-vial impedance spectroscopy of the mechanisms of annealing in the freeze-drying of maltodextrin: the impact of annealing hold time and temperature on the primary drying rate.

    Science.gov (United States)

    Smith, Geoff; Arshad, Muhammad Sohail; Polygalov, Eugene; Ermolina, Irina

    2014-06-01

    The study aims to investigate the impact of annealing hold time and temperature on the primary drying rate/duration of a 10% (w/v) solution of maltodextrin with an emphasis on how the mechanisms of annealing might be understood from the in-vial measurements of the ice crystal growth and the glass transition. The electrical impedance of the solution within a modified glass vial was recorded between 10 and 10(6) Hz during freeze-drying cycles with varying annealing hold times (1-5 h) and temperatures. Primary drying times decreased by 7%, 27% and 34% (1.1, 4.3 and 5.5 h) with the inclusion of an annealing step at temperatures of -15°C, -10°C and -5°C, respectively. The glass transition was recorded at approximately -16°C during the re-heating and re-cooling steps, which is close to the glass transition (Tg ') reported for 10% (w/v) maltodextrin and therefore indicates that a maximum freeze concentration (∼86%, w/w, from the Gordon-Taylor equation) was achieved during first freezing, with no further ice being formed on annealing. This observation, coupled to the decrease in electrical resistance that was observed during the annealing hold time, suggests that the reduction in the drying time was because of improved connectivity of ice crystals because of Ostwald ripening rather than devitrification.

  19. New particle-dependent parameterizations of heterogeneous freezing processes: sensitivity studies of convective clouds with an air parcel model

    Directory of Open Access Journals (Sweden)

    K. Diehl

    2015-06-01

    Full Text Available Based on the outcome of laboratory results, new particle-dependent parameterizations of heterogeneous freezing were derived and used to improve and extend a two-dimensional spectral microphysics scheme. They include (1 a particle-type dependent parameterization of immersion freezing using the numbers of active sites per mass, (2 a particle-type and size-resolved parameterization of contact freezing, and (3 a particle-type dependent description of deposition freezing. The modified microphysical scheme was embedded in an adiabatic air parcel model with entrainment. Sensitivity studies were performed to simulate convective situations and the impact of ice nuclei concentrations and types on ice formation. As a central diagnostic parameter the ice water fraction IWF was selected which is the relation of the ice water content to the total water content. The following parameters were varied: initial aerosol particle number size distributions, types of ice nucleating particles, strength of convection, and the fractions of potential ice nucleating particles. Single and coupled freezing processes were investigated. The results show that immersion freezing seems to be the most efficient process and, in competition with contact freezing, the dominant process. Contact freezing is constrained by the collision kernel between supercooled drops and potential ice nucleating particles and becomes relevant at temperatures lower than −25 °C. The importance of deposition freezing lies in secondary ice formation, i.e. small ice particles produced by deposition nucleation trigger the freezing of supercooled drops by collisions. Thus, a broader ice particle spectrum is generated than by immersion and contact freezing. Competition of contact and deposition freezing is negligible because of involved particle sizes. As already suggested in literature, mineral dust particles seem to be the most important ice nucleating particles. Biological particles are probably not

  20. Socket preservation using demineralized freezed dried bone allograft with and without plasma rich in growth factor: A canine study

    Directory of Open Access Journals (Sweden)

    Ahmad Mogharehabed

    2014-01-01

    Full Text Available Background: The accelerating effect of plasma rich in growth factors (PRGFs in the healing of extraction sockets has been demonstrated by some studies. The aim of the present study was to histologically and histomorphometrically evaluate whether bone formation would increase by the combined use of PRGF and demineralized freeze-dried bone allograft (DFDBA. Materials and Methods: In four female dogs, the distal root of the second, third and fourth lower premolars were extracted bilaterally and the mesial roots were preserved. The extraction sockets were randomly divided into DFDBA + PRGF, DFDBA + saline or control groups. Two dogs were sacrificed after 2 weeks and two dogs were sacrificed after 6 weeks. The extraction sockets were evaluated from both histological and histomorphometrical aspects. The data were analyzed by Mann-Whitney followed by Kruskal-Wallis tests using the Statistical Package for the Social Sciences version 20 (SPSS Inc., Chicago, IL, USA. Significant levels were set at 0.05. Results: The least decrease in socket height was observed in the DFDBA + PRGF group (0.73 ± 0.42 mm. The least decrease in the coronal portion was observed in the DFDBA + PRGF group (1.38 ± 1.35 mm². The least decrease in the middle surface was observed in the DFDBA group (0.61 ± 0.80 mm². The least decrease in the apical portion was observed in the DFDBA group (0.34 ± 0.39 mm². Conclusion: The present study showed better socket preservation subsequent to the application of DFDBA and PRGF combination in comparison with the two other groups. However, the difference was not statistically significant.

  1. Prevention and therapy of squamous cell carcinoma of the rodent esophagus using freeze-dried black raspberries

    Institute of Scientific and Technical Information of China (English)

    Gary D STONER; Robeena M AZIZ

    2007-01-01

    Aim: This study was conducted to determine if short-term treatment of N-nitrosomethylbenzylamine (NMBA)-induced tumors in the rat esophagus with dietary freeze-dried black raspberries (FBR) would result in tumor regression and enhanced survival of the animals. Methods: Four-week-old male Fisher-344 ratswere administered an AIN-76A control diet and injected subcutaneously with 0.5 mg/kg NMBA once per week for 15 weeks. At 19 weeks, when rats had an average of 5-6 tumors (papillomas) per esophagus, they were given a control diet contain-ing either 5%, 10%, or 20% FBR. After 7 weeks of berry treatment, all surviving rats were killed and tumor incidence, number and volume were determined. Results:Esophageal tumor incidences, numbers and volumes in NMBA-treated rats were not influenced by any of the berry treatments. There were progressive increases in the survival of NMBA-treated rats fed 5%-20% FBR diets; however, these increases were not significant. Conclusion: FBR at 5%, 10%, and 20% of the diet had no effect on the development of NMBA-induced tumors in the rat esophagus or on animal survival when administered for 7 weeks beginning at the papilloma stage of tumor development. Thus, FBR appear to have no therapeutic value in the treatment of esophageal tumors. In contrast, dietary FBR are highly effectivein preventing the development of NMBA-induced esophageal tumors in rats when administered before and during NMBA treatment or shortly after NMBA treat-ment when the esophagi contain preneoplastic (dysplastic) lesions of varyingdegrees of severity.

  2. Determination of orthodontic tooth movement and tissue reaction following demineralized freeze-dried bone allograft grafting intervention

    Directory of Open Access Journals (Sweden)

    Massoud Seifi

    2012-01-01

    Full Text Available Background: Socket preservation after tooth extraction is one of the indications of bone grafting to enhance preorthodontic condition. The aim of this study is to determine the effects of socket preservation on the immediate tooth movement, alveolar ridge height preservation and orthodontic root resorption. Materials and Methods: In a split-mouth technique, twelve sites in three dogs were investigated as an experimental study. Crushed demineralized freeze-dried bone allograft (DFDBA (CenoBone® was used as the graft material. The defects were made by the extraction of 3 rd premolar. On one side of each jaw, the defects were preserved by DFDBA and defects of the other side left opened as the control group. Simultaneously the teeth adjacent to the defects were pulled together by a NiTi coil spring. After eight weeks, the amount of (OTM, alveolar height, and root resorption were measured. Analysis of variance was used for purpose of comparison. Results: There was a slight increase in OTM at grafted sites as they were compared to the control sites (P<0.05. Also a significant bone resorption in control site and successful socket preservation in experimental site were observed. Reduction of root resorption at the augmented site was significant compared to the normal healing site (P<0.05. Conclusion: Using socket preservation, tooth movement can be immediately started without waiting for the healing of the recipient site. This can provide some advantages like enhanced rate of OTM, its approved effects on ridge preservation that reduces the chance of dehiscence and the reduction of root resorption.

  3. Assessment of Fevicol (adhesive Drying Process through Dynamic Speckle Techniques

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    Mohammad Z. Ansari

    2015-04-01

    Full Text Available Dynamic laser speckle (or biospeckle analysis is a useful measurement tool to analyze micro-motion on a sample surface via temporal statistics based on a sequence of speckle images. The aim of this work was to evaluate the use of dynamic speckles as an alternative tool to monitoring Fevicol drying process. Experimental demonstration of intensity-based algorithm to monitor Fevicol drying process is reported. The experiment was explored with the technique called Inertia Moment of co-occurrence matrix. The results allowed verifying the drying process and it was possible to observe different activity stages during the drying process. Statistical Tukey test at 5% significance level allowed differentiating different stages of drying. In conclusion, speckle activity, measured by the Inertia Moment, can be used to monitor drying processes of the Fevicol.

  4. 9 CFR 590.540 - Spray process drying facilities.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Spray process drying facilities. 590.540 Section 590.540 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF..., Processing, and Facility Requirements § 590.540 Spray process drying facilities. (a) Driers shall be of...

  5. Lactobacillus pentosus DSM 16366 starter added to brine as freeze-dried and as culture in the nutritive media for Spanish style green olive production

    Directory of Open Access Journals (Sweden)

    Peres, Cidália

    2008-09-01

    Full Text Available Lactobacillus pentosus DSM 16366, a strain originally isolated from olive fermentation, was used as a starter culture for "Azeiteira" the preparation of Spanish style green olives. Inoculum was added to the fermentors as a freezedried starter culture or as a culture in the nutritive media. Lactic acid fermentation induction produced a more rapid acidification of brines and reduced the survival period of Enterobacteriaceae compared with the uninoculated process. The best results were obtained using the nutritive media as a culture carrier rather than the freeze-dried starter.En este trabajo se empleo el inóculo Lactobacillus pentosus DSM 16366 liofilizado y en caldo nutritivo para preparación de aceitunas "Azeiteira" tipo verde, estilo sevillano. En las salmueras inoculadas se observó una acidificación más rápida y reducción del periodo de supervivencia de las Enterobacteriaceae, especialmente cuando se aplicó el inóculo en caldo nutritivo.

  6. Preparation of poly (L-lactic acid) microspheres by droplet-freezing process

    Energy Technology Data Exchange (ETDEWEB)

    Mao Yi [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Jiangsu Key Laboratory of Advanced Metallic Materials, Nanjing 211189 (China); Dong Yinsheng, E-mail: dongys@seu.edu.cn [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Jiangsu Key Laboratory of Advanced Metallic Materials, Nanjing 211189 (China); Lin Pinghua [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Huazhong University of Science and Technology, Wuhan 430074 (China); Chu Chenglin; Sheng Xiaobo; Guo Chao [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Jiangsu Key Laboratory of Advanced Metallic Materials, Nanjing 211189 (China)

    2011-01-01

    A recently developed process of microsphere preparation, named droplet-freezing process is introduced in this paper. The PLLA microspheres were fabricated by the droplet-freezing process, the diameter and porosity of the microspheres were measured, and the micro-morphologies of the microspheres were characterized by scanning electron microscopy (SEM). The formation process of microspheres was achieved by two steps: first, after droplets dropped off the delivery tube, they became approximately spherical in the air under the effect of the surface tension; second, droplets dropped into liquid condensate and maintained the spherical shape, and were frozen during the free settling process. Experimental results indicated that the microspheres fabricated by the droplet-freezing process have uniform diameters and the diameter can be controlled properly, along with the increase of the PLLA concentration, the size of microspheres increases, but the porosity of the microspheres decreases. The microspheres with high porosity can be obtained with a low concentration of the PLLA solution. SEM analysis revealed that the surfaces and interiors of the microsphere contain plentiful and interconnected micro pores. The microspheres are hopeful to be applied in bone tissue engineering.

  7. Exergetic simulation of a combined infrared-convective drying process

    Science.gov (United States)

    Aghbashlo, Mortaza

    2016-04-01

    Optimal design and performance of a combined infrared-convective drying system with respect to the energy issue is extremely put through the application of advanced engineering analyses. This article proposes a theoretical approach for exergy analysis of the combined infrared-convective drying process using a simple heat and mass transfer model. The applicability of the developed model to actual drying processes was proved using an illustrative example for a typical food.

  8. An improved high performance liquid chromatography-photodiode array detection-atmospheric pressure chemical ionization-mass spectrometry method for determination of chlorophylls and their derivatives in freeze-dried and hot-air-dried Rhinacanthus nasutus (L.) Kurz.

    Science.gov (United States)

    Kao, Tsai Hua; Chen, Chia Ju; Chen, Bing Huei

    2011-10-30

    Rhinacanthus nasutus (L.) Kurz, a traditional Chinese herb possessing antioxidant and anti-cancer activities, has been reported to contain functional components like carotenoids and chlorophylls. However, the variety and amount of chlorophylls remain uncertain. The objectives of this study were to develop a high performance liquid chromatography-photodiode array detection-atmospheric pressure chemical ionization-mass spectrometry (HPLC-DAD-APCI-MS) method for determination of chlorophylls and their derivatives in hot-air-dried and freeze-dried R. nasutus. An Agilent Eclipse XDB-C18 column and a gradient mobile phase composed of methanol/N,N-dimethylformamide (97:3, v/v), acetonitrile and acetone were employed to separate internal standard zinc-phthalocyanine plus 12 cholorophylls and their derivatives within 21 min, including chlorophyll a, chlorophyll a', hydroxychlorophyll a, 15-OH-lactone chlorophyll a, chlorophyll b, chlorophyll b', hydroxychlorophyll b, pheophytin a, pheophytin a', hydroxypheophytin a, hydroxypheophytin a' and pheophytin b in hot-air-dried R. nasutus with flow rate at 1 mL/min and detection at 660 nm. But, in freeze-dried R. nasutus, only 4 chlorophylls and their derivatives, including chlorophyll a, chlorophyll a', chlorophyll b and pheophytin a were detected. Zinc-phthalocyanine was found to be an appropriate internal standard to quantify all the chlorophyll compounds. After quantification by HPLC-DAD, both chlorophyll a and pheophytin a were the most abundant in hot-air-dried R. nasutus, while in freeze-dried R. nasutus, chlorophyll a and chlorophyll b dominated.

  9. Microcrystalline cellulose, a useful alternative for sucrose as a matrix former during freeze-drying of drug nanosuspensions - a case study with itraconazole.

    Science.gov (United States)

    Van Eerdenbrugh, Bernard; Vercruysse, Sofie; Martens, Johan A; Vermant, Jan; Froyen, Ludo; Van Humbeeck, Jan; Van den Mooter, Guy; Augustijns, Patrick

    2008-10-01

    Itraconazole nanosuspensions, stabilized with 10% TPGS (relative to the weight of itraconazole), were transformed into nanoparticulate powders by freeze-drying. The crystalline itraconazole nanoparticles showed peak broadening in the X-ray powder diffraction spectra and a lower melting point as inferred from differential scanning calorimetry. As it was found that freeze-drying compromised dissolution behavior, sucrose was added as a matrix, former (50,100 and 200%, relative to the weight of itraconazole). Higher amounts of sucrose unexpectedly resulted in a decrease in the dissolution rate. After thorough evaluation of the powders, it was found that whereas higher sucrose content showed a cryoprotective effect, agglomeration during the final phase of the subsequent drying step tended to increase with higher amounts of sucrose. Therefore, microcrystalline cellulose (MCC) was evaluated as an alternative matrix former. The inclusion of MCC resulted in fast dissolution that increased with increasing amounts of MCC [for powders containing 50%,100% and 200% MCC, (relative to the weight of itraconazole), the times required for 63.2% release were 10.5+/-0.7, 6.4+/-1.2 and 3.1+/-0.5min, respectively]. The dissolution profiles showed an initial phase of burst dissolution, followed by a phase of slower release. As the fraction showing burst dissolution increased with higher MCC content, the system holds promise to maintain the dissolution enhancing properties of nanoparticles in the dry form.

  10. Persistence and survival of pathogens in dry foods and dry food processing environments

    NARCIS (Netherlands)

    L. Beuchat; E. Komitopoulou; R. Betts; H. Beckers; F. Bourdichon; H. Joosten; S. Fanning; B. ter Kuile

    2011-01-01

    Low-moisture foods and food ingredients, i.e., those appearing to be dry or that have been subjected to a drying process, represent important nutritional constituents of human diets. Some of these foods are naturally low in moisture, such as cereals, honey and nuts, whereas others are produced from

  11. Effect of freeze drying on the metabolic viability of lactic acid bacteria%冷冻干燥对乳酸菌代谢活力的影响

    Institute of Scientific and Technical Information of China (English)

    李宝坤; 田丰伟; 刘小鸣; 赵建新; 张灏; 宋元达; 陈卫

    2011-01-01

    The survival rates of Lactobacillus plantarum ST-Ⅲ and Lactobacillus bulgaricus in the presence of cryoprotectants such as 15%sucrose,10%trehalose,15%sucrose +2% sodium glutamate and 10%reconstituted skim milk(RSM)were estimated.In addition,we determined the activities of hexokinase(HK),pyruvate kinase(PK),lactate dehydrogenase(LDH),extracellular proteins was higher and intercellular Ca2+ immediately following the freeze-drying.The results showed that the differences in HK and PK activities with and without the cryoprotectants during freeze-drying were not significant,but activities of LDH were significantly different prior to and after freeze-drying.Meanwhile,the results showed extracellular proteins was higher and intercellular Ca2+ was lower in absence of cryoprotectants than in the presence of cryoprotectants.These results suggested that freeze-dying inactivated key enzymes(LDH)and damaged membrane structure and function.These led to decrease in viability of lactic acid bacteria during freeze-drying.%以保加利亚乳杆菌和植物乳杆菌ST-Ⅲ为研究对象,用15%蔗糖、10%海藻糖、15%蔗糖+2%谷氨酸钠及10%脱脂乳为冷冻保护剂,与不加冷冻保护剂的样品进行冻干后菌种活力的对比,测定冷冻干燥后菌体中己糖激酶、丙酮酸激酶、乳酸脱氢酶的活力,胞外蛋白及胞内Ca2+的浓度变化。结果表明:冷冻干燥对菌体的己糖激酶和丙酮酸激酶影响不显著,对乳酸脱氢酶具有显著性的影响。同时,不加保护剂菌体的胞外蛋白含量明显高于添加保护剂的,而胞内Ca2+却远低于其他组。这一结果说明,冷冻干燥使代谢关键酶如乳酸脱氢酶失活,同时对细胞膜造成了损伤,从而引起细胞代谢活力的下降。

  12. Transformation Process of Freezing Stations%冷冻站工艺改造浅析

    Institute of Scientific and Technical Information of China (English)

    王应华

    2015-01-01

    对冷冻站装置在运行中发生溶液冷却器频繁泄漏的原因进行了分析,并提出了工艺技术改造的措施。%Leakage reasons of the solution cooler for freezing station device occurred in the operation were analyzed,and the measures of the transformation process were pointed out.

  13. Determination of volatile components in fresh, frozen, and freeze-dried Padrón-type peppers by gas chromatography-mass spectrometry using dynamic headspace sampling and microwave desorption.

    Science.gov (United States)

    Oruña-Concha, M J; López-Hernández, J; Simal-Lozano, J A; Simal-Gándara, J; González-Castro, M J; de la Cruz García, C

    1998-12-01

    "Padrón-type" peppers are a small variety of Capsicum annuum cultivated mainly in Galicia, Spain. To compare the effects of freezing and freeze-drying on the volatile components of Padrón-type peppers, preserved samples are analyzed by means of dynamic headspace sampling on an adsorbent followed by microwave desorption into a gas chromatograph equipped with a mass spectrometric detector. Sixty-five compounds are identified, including hydrocarbons, terpenes, alcohols, phenols, ethers, aldehydes, ketones, esters, pyrroles, pyrazines, and sulfurous compounds. Fresh whole, homogenized, and freeze-dried peppers have characteristic volatile-component profiles, whereas frozen peppers have a highly variable volatile-component profile.

  14. Heat and Mass Transfer of the Droplet Vacuum Freezing Process Based on the Diffusion-controlled Evaporation and Phase Transition Mechanism

    Science.gov (United States)

    Zhang, Zhijun; Gao, Jingxin; Zhang, Shiwei

    2016-10-01

    A frozen phase transition model is developed to investigate the heat and mass transfer of a single water droplet during the vacuum freezing process. The model is based on the diffusion-controlled evaporation mechanism and phase transition characteristics. The droplet vacuum freezing process can be divided into three stages according to the droplet states and the time order. It includes the evaporation freezing stage, the isothermal freezing stage and the sublimation freezing stage. A numerical calculation is performed, and the result is analysed. The effects of the vacuum chamber pressure, initial droplet diameter and initial droplet temperature on the heat and mass transfer characteristics at each stage are studied. The droplet experiences supercooling breakdown at the end of the evaporation freezing stage before the isothermal freezing stage begins. The temperature is transiently raised as a result of the supercooling breakdown phenomenon, whose effects on the freezing process and freezing parameters are considered.

  15. Clinical and Histomorphometric Assessment of Lateral Alveolar Ridge Augmentation Using a Corticocancellous Freeze-Dried Allograft Bone Block.

    Science.gov (United States)

    Ahmadi, Roya Shariatmadar; Sayar, Ferena; Rakhshan, Vahid; Iranpour, Babak; Jahanbani, Jahanfar; Toumaj, Ahmad; Akhoondi, Nasrin

    2017-06-01

    Horizontal ridge augmentation with allografts has attracted notable attention because of its proper success rate and the lack of disadvantages of autografts. Corticocancellous block allografts have not been adequately studied in humans. Therefore, this study clinically and histomorphometrically evaluated the increase in ridge width after horizontal ridge augmentation using corticocancellous block allografts as well as implant success after 12 to 18 months after implantation. In 10 patients receiving implants (3 women, 7 men; mean age = 45 years), defective maxillary alveolar ridges were horizontally augmented using freeze-dried bone allograft blocks. Ridge widths were measured before augmentation, immediately after augmentation, and ∼6 months later in the reentry surgery for implantation. This was done at points 2 mm (A) and 5 mm (B) apically to the crest. Biopsy cores were acquired from the implantation site. Implant success was assessed 15.1 ± 2.7 months after implantation (range = 12-18 months). Data were analyzed using Friedman and Dunn tests (α = 0.05). At point A, ridge widths were 2.77 ± 0.37, 8.02 ± 0.87, and 6.40 ± 0.66 mm, respectively, before surgery, immediately after surgery, and before implantation. At point B, ridge widths were 3.40 ± 0.39, 9.35 ± 1.16, and 7.40 ± 1.10 mm, respectively, before surgery, immediately after surgery, and before implantation. The Friedman test showed significant increases in ridge widths, both at point A and point B (both P = .0000). Postaugmentation resorption was about 1.5-2 mm and was statistically significant at points A and B (P < .05, Dunn). The percentage of newly formed bone, residual graft material, and soft tissue were 33.0% ± 11.35% (95% confidence interval [CI] = 24.88%-41.12%), 37.50% ± 19.04% (95% CI = 23.88%-51.12%), and 29.5%, respectively. The inflammat