Enhancement of photoassimilate utilization by manipulation of starch regulatory enzymes

Energy Technology Data Exchange (ETDEWEB)

Okita, Thomas W. [Washington State Univ., Pullman, WA (United States)

2016-05-11

ADPglucose pyrophosphorylase (AGPase) and the plastidial starch phosphorylase1 (Pho1) are two regulatory enzymes whose catalytic activities are essential for starch granule synthesis. Conversion of the pre-starch granule to the mature form is dependent on AGPase, which produces ADPglucose, the substrate used by starch synthases. The catalytic activity of AGPase is controlled by small effector molecules and a prime goal of this project was to decipher the role of the two subunit types that comprise the heterotetrameric enzyme structure. Extensive genetic and biochemical studies showed that catalysis was contributed mainly by the small subunit although the large subunit was required for maximum activity. Both subunits were needed for allosteric regulatory properties. We had also demonstrated that the AGPase catalyzed reaction limits the amount of starch accumulation in developing rice seeds and that carbon flux into rice seed starch can be increased by expression of a cytoplasmic-localized, up-regulated bacterial AGPase enzyme form. Results of subsequent physiological and metabolite studies showed that the AGPase reaction is no longer limiting in the AGPase transgenic rice lines and that one or more downstream processes prevent further increases in starch biosynthesis. Further studies showed that over-production of ADPglucose dramatically alters the gene program during rice seed development. Although the expression of nearly all of the genes are down-regulated, levels of a starch binding domain containing protein (SBDCP) are elevated. This SBDCP was found to bind to and inhibit the catalytic activity of starch synthase III and, thereby preventing maximum starch synthesis from occurring. Surprisingly, repression of SBDCP elevated expression of starch synthase III resulting in increasing rice grain weight. A second phase of this project examined the structure-function of Pho1, the enzyme required during the initial phase of pre-starch granule formation and its

Synthesis and Properties of Reactive Interfacial Agents for Polycaprolactone-Starch Blends

NARCIS (Netherlands)

Sugih, Asaf K.; Drijfhout, Jan. P.; Picchioni, Francesco; Janssen, Leon P. B. M.; Heeres, Hero J.

2009-01-01

The synthesis of two reactive interfacial agents for starch-polycaprolactone (PCL) blends, PCL-g-glycidyl methacrylate (PCL-g-GMA) and PCL-g-diethyl maleate (PCL-g-DEM) is described. The compounds were prepared by reacting a low molecular weight PCL. (M(w) 3000) with GMA or DEM in the presence of

Maltase-glucoamylase: Mucosal regulator of prandial starch glucogenesis and complimentary hepatic gluconeogenesis of mice

Science.gov (United States)

In previous studies we have shown that maltase-glucoamylase (Mgam) is required for efficient starch digestion and insulin response to starch feeding. It was hypothesized that the slower rate of starch digestion by residual sucrase-isomaltase (Si) maltase failed to regulate gluconeogenesis. Here, rat...

TaGW2-6A allelic variation contributes to grain size possibly by regulating the expression of cytokinins and starch-related genes in wheat.

Science.gov (United States)

Geng, Juan; Li, Liqun; Lv, Qian; Zhao, Yi; Liu, Yan; Zhang, Li; Li, Xuejun

2017-12-01

Functional allelic variants of TaGW2 - 6A produce large grains, possibly via changes in endosperm cells and dry matter by regulating the expression of cytokinins and starch-related genes via the ubiquitin-proteasome system. In wheat, TaGW2-6A coding region allelic variants are closely related to the grain width and weight, but how this region affects grain development has not been fully elucidated; thus, we explored its influence on grain development based mainly on histological and grain filling analyses. We found that the insertion type (NIL31) TaGW2-6A allelic variants exhibited increases in cell numbers and cell size, thereby resulting in a larger (wider) grain size with an accelerated grain milk filling rate, and increases in grain width and weight. We also found that cytokinin (CK) synthesis genes and key starch biosynthesis enzyme AGPase genes were significantly upregulated in the TaGW2-6A allelic variants, while CK degradation genes and starch biosynthesis-negative regulators were downregulated in the TaGW2-6A allelic variants, which was consistent with the changes in cells and grain filling. Thus, we speculate that TaGW2-6A allelic variants are linked with CK signaling, but they also influence the accumulation of starch by regulating the expression of related genes via the ubiquitin-proteasome system to control the grain size and grain weight.

Inferring transcriptional gene regulation network of starch metabolism in Arabidopsis thaliana leaves using graphical Gaussian model

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Ingkasuwan Papapit

2012-08-01

Full Text Available Abstract Background Starch serves as a temporal storage of carbohydrates in plant leaves during day/night cycles. To study transcriptional regulatory modules of this dynamic metabolic process, we conducted gene regulation network analysis based on small-sample inference of graphical Gaussian model (GGM. Results Time-series significant analysis was applied for Arabidopsis leaf transcriptome data to obtain a set of genes that are highly regulated under a diurnal cycle. A total of 1,480 diurnally regulated genes included 21 starch metabolic enzymes, 6 clock-associated genes, and 106 transcription factors (TF. A starch-clock-TF gene regulation network comprising 117 nodes and 266 edges was constructed by GGM from these 133 significant genes that are potentially related to the diurnal control of starch metabolism. From this network, we found that β-amylase 3 (b-amy3: At4g17090, which participates in starch degradation in chloroplast, is the most frequently connected gene (a hub gene. The robustness of gene-to-gene regulatory network was further analyzed by TF binding site prediction and by evaluating global co-expression of TFs and target starch metabolic enzymes. As a result, two TFs, indeterminate domain 5 (AtIDD5: At2g02070 and constans-like (COL: At2g21320, were identified as positive regulators of starch synthase 4 (SS4: At4g18240. The inference model of AtIDD5-dependent positive regulation of SS4 gene expression was experimentally supported by decreased SS4 mRNA accumulation in Atidd5 mutant plants during the light period of both short and long day conditions. COL was also shown to positively control SS4 mRNA accumulation. Furthermore, the knockout of AtIDD5 and COL led to deformation of chloroplast and its contained starch granules. This deformity also affected the number of starch granules per chloroplast, which increased significantly in both knockout mutant lines. Conclusions In this study, we utilized a systematic approach of microarray

Potato starch synthases

NARCIS (Netherlands)

Nazarian-Firouzabadi, Farhad; Visser, Richard G.F.

2017-01-01

Starch, a very compact form of glucose units, is the most abundant form of storage polyglucan in nature. The starch synthesis pathway is among the central biochemical pathways, however, our understanding of this important pathway regarding genetic elements controlling this pathway, is still

Starch accumulation in hulless barley during grain filling.

Science.gov (United States)

Zheng, Xu-Guang; Qi, Jun-Cang; Hui, Hong-Shan; Lin, Li-Hao; Wang, Feng

2017-12-01

Starch consists of two types of molecules: amylose and amylopectin. The objective of this study was increase understanding about mechanisms related to starch accumulation in hulless barley (Hordeum vulgare L.) grain by measuring temporal changes in (i) grain amylose and amylopectin content, (ii) starch synthase activity, and (iii) the relative expressions of key starch-related genes. The amylopectin/amylose ratio gradually declined in both Beiqing 6 and Kunlun 12. In both cultivars, the activities of adenosine diphosphate glucose pyrophosphorylase, soluble starch synthase (SSS), granule bound starch synthase (GBSS), and starch branching enzyme (SBE) increased steadily during grain filling, reaching their maximums 20-25 days after anthesis. The activities of SSS and SBE were greater in Ganken 5 than in either Beiqing 6 or Kunlun 12. The expression of GBSS I was greater in Beiqing 6 and Kunlun 12 than in Ganken 5. In contrast, the expression of SSS I, SSS II and SBE I was greater in Ganken 5 than in Beiqing 6 and Kunlun 12. The peak in GBSS I expression was later than that of SSS I, SSS II, SBE IIa and SBE IIb. The GBSS I transcript in Kunlun 12 was expressed on average 90 times more than the GBSS II transcript. The results suggest that SBE and SSS may control starch synthesis at the transcriptional level, whereas GBSS I may control starch synthesis at the post transcriptional level. GBSS I is mainly responsible for amylose synthesis whereas SSS I and SBE II are mainly responsible for amylopectin synthesis in amyloplasts.

Dynamics of starch granule biogenesis - the role of redox-regulated enzymes and low-affinity carbohydrate-binding modules

DEFF Research Database (Denmark)

Blennow, A.; Svensson, Birte

2010-01-01

The deposition and degradation of starch in plants is subject to extensive post-translational regulation. To permit degradation of B-type crystallites present in tuberous and leaf starch these starch types are phosphorylated by glucan, water dikinase (GWD). At the level of post-translational redo...

Synthesis and characterization of polystyrene-starch polyblend

International Nuclear Information System (INIS)

Tetty Kemala; M Syaeful Fahmi; Suminar S Achmadi

2010-01-01

Polystyrene foam (PS) is a polymer that is widely used but not biodegradable. Therefore, PS-starch polyblend was developed. In this research the effect of glycerol as plasticizer was evaluated based on mechanical and thermal analyses. PS-starch polyblends were produced by mixing PS and starch solution with composition ratios of 60:40, 65:35, 70:30, 75:25, and 80:20 percent by weight. Polylactic acid (20 %) was added as compatibilizer. The polyblends were analyzed its tensile strength, thermal properties, and density. The PS-starch polyblends were white opaque in color and fragile. The properties of tensile strength and density of the polyblends were in the range of that of pure PS. The tensile strength and density increases as PS constituents increasing with the best composition ratio of 80 PS to 20 of starch. Peak of glass transition and melting point seen a single on composition ration 80 PS to 20 of starch. Additional amount of glycerol did not affect the thermal property, but has caused a slight decrease in tensile strength and density. (author)

Study on the synthesis and physicochemical properties of starch acetate with low substitution under microwave assistance.

Science.gov (United States)

Lin, Derong; Zhou, Wei; Zhao, Jingjing; Lan, Weijie; Chen, Rongming; Li, Yutong; Xing, Baoshan; Li, Zhuohao; Xiao, Mengshi; Wu, Zhijun; Li, Xindan; Chen, Rongna; Zhang, Xingwen; Chen, Hong; Zhang, Qing; Qin, Wen; Li, Suqing

2017-10-01

In this study, synthesis and physicochemical properties of starch acetate with low substitution under microwave were studied. A three-level-three-factorial Central Composite Design using Response Surface Methodology (RSM) was employed to optimize the reaction conditions. The optimal parameters are as follows: amount of acetic anhydride of 12%, radiation time of 11min, and microwave power of 100W. These optimal conditions predicted by RSM were confirmed that the degree of substitution (DS) of acetate starch is 0.0691mg/g and the physical and chemical properties of natural corn starch (NCS) and corn starch acetate (ACS) were further studied.The transparency, water separation, water absorption, expansion force, and solubility of ACS low substitution are better than NCS, while the NCS's hydrolysis percentage is higher than ACS, which indicate that the modified corn starch has better performance than native corn starch. The surface morphology of the corn starch acetate was examined by scanning electron microscope (SEM), which showed that it had a smooth surface and a spherical and polygonal shape. However, samples' shape is irregular. Crystal structure was observed by X-ray diffraction, and the ACS can determine the level of microwave technology that can destroy the extent of the crystal and amorphous regions. Fourier transform infrared (FTIR) spectroscopy shows that around 1750cm -1 carbonyl signal determines acetylation bonding successfully. Copyright © 2017 Elsevier B.V. All rights reserved.

Identification of genes encoding granule-bound starch synthase involved in amylose metabolism in banana fruit.

Directory of Open Access Journals (Sweden)

Hongxia Miao

Full Text Available Granule-bound starch synthase (GBSS is responsible for amylose synthesis, but the role of GBSS genes and their encoded proteins remains poorly understood in banana. In this study, amylose content and GBSS activity gradually increased during development of the banana fruit, and decreased during storage of the mature fruit. GBSS protein in banana starch granules was approximately 55.0 kDa. The protein was up-regulated expression during development while it was down-regulated expression during storage. Six genes, designated as MaGBSSI-1, MaGBSSI-2, MaGBSSI-3, MaGBSSI-4, MaGBSSII-1, and MaGBSSII-2, were cloned and characterized from banana fruit. Among the six genes, the expression pattern of MaGBSSI-3 was the most consistent with the changes in amylose content, GBSS enzyme activity, GBSS protein levels, and the quantity or size of starch granules in banana fruit. These results suggest that MaGBSSI-3 might regulate amylose metabolism by affecting the variation of GBSS levels and the quantity or size of starch granules in banana fruit during development or storage.

Identification of Genes Encoding Granule-Bound Starch Synthase Involved in Amylose Metabolism in Banana Fruit

Science.gov (United States)

Liu, Weixin; Xu, Biyu; Jin, Zhiqiang

2014-01-01

Granule-bound starch synthase (GBSS) is responsible for amylose synthesis, but the role of GBSS genes and their encoded proteins remains poorly understood in banana. In this study, amylose content and GBSS activity gradually increased during development of the banana fruit, and decreased during storage of the mature fruit. GBSS protein in banana starch granules was approximately 55.0 kDa. The protein was up-regulated expression during development while it was down-regulated expression during storage. Six genes, designated as MaGBSSI-1, MaGBSSI-2, MaGBSSI-3, MaGBSSI-4, MaGBSSII-1, and MaGBSSII-2, were cloned and characterized from banana fruit. Among the six genes, the expression pattern of MaGBSSI-3 was the most consistent with the changes in amylose content, GBSS enzyme activity, GBSS protein levels, and the quantity or size of starch granules in banana fruit. These results suggest that MaGBSSI-3 might regulate amylose metabolism by affecting the variation of GBSS levels and the quantity or size of starch granules in banana fruit during development or storage. PMID:24505384

First principles insight into the α-glucan structures of starch

DEFF Research Database (Denmark)

Damager, Iben; Engelsen, Søren Balling; Blennow, Andreas

2010-01-01

A study was conducted to demonstrate the synthesis, conformation, and hydration of the α-glucan structures of starch. Starch and glycogen were synthesized by sets of specific enzyme activities that directly determined their molecular structures and physical properties. It was demonstrated...... that the extent of crystallinity, aggregation and hydration was of fundamental importance for starch and its human analogue glycogen. Starch was deposited in the plant as a stable form in highly organized and semicrystalline granules having specific crystalline polymorphs as determined by powder X......-ray crystallography. The investigations mainly focused on the bottom-up approach of synthesis, conformation, and hydration of starch. Starch and glycogen were found to be polymers that were built up from a single monomer, D-glucopyranose, or for short D-glucose....

Dynamical feedback between circadian clock and sucrose availability explains adaptive response of starch metabolism to various photoperiods

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Francois Gabriel Feugier

2013-01-01

Full Text Available Plants deal with resource management during all their life. During the day they feed on photosynthetic carbon, sucrose, while storing a part into starch for night use. Careful control of carbon partitioning, starch degradation and sucrose export rates is crucial to avoid carbon starvation, insuring optimal growth whatever the photoperiod. Efficient regulation of these key metabolic rates can give an evolutionary advantage to plants. Here we propose a model of adaptive starch metabolism in response to various photoperiods. We assume the three key metabolic rates to be circadian regulated in leaves and that their phases of oscillations are shifted in response to sucrose starvation. We performed gradient descents for various photoperiod conditions to find the corresponding optimal sets of phase shifts that minimize starvation. Results at convergence were all consistent with experimental data: i diurnal starch profile showed linear increase during the day and linear decrease at night; ii shorter photoperiod tended to increase starch synthesis speed while decreasing its degradation speed during the longer night; iii sudden early dusk showed slower starch degradation during the longer night. Profiles that best explained observations corresponded to circadian regulation of all rates. This theoretical study would establish a framework for future research on feedback between starch metabolism and circadian clock as well as plant productivity.

Starch as a major integrator in the regulation of plant growth

Science.gov (United States)

Sulpice, Ronan; Pyl, Eva-Theresa; Ishihara, Hirofumi; Trenkamp, Sandra; Steinfath, Matthias; Witucka-Wall, Hanna; Gibon, Yves; Usadel, Björn; Poree, Fabien; Piques, Maria Conceição; Von Korff, Maria; Steinhauser, Marie Caroline; Keurentjes, Joost J. B.; Guenther, Manuela; Hoehne, Melanie; Selbig, Joachim; Fernie, Alisdair R.; Altmann, Thomas; Stitt, Mark

2009-01-01

Rising demand for food and bioenergy makes it imperative to breed for increased crop yield. Vegetative plant growth could be driven by resource acquisition or developmental programs. Metabolite profiling in 94 Arabidopsis accessions revealed that biomass correlates negatively with many metabolites, especially starch. Starch accumulates in the light and is degraded at night to provide a sustained supply of carbon for growth. Multivariate analysis revealed that starch is an integrator of the overall metabolic response. We hypothesized that this reflects variation in a regulatory network that balances growth with the carbon supply. Transcript profiling in 21 accessions revealed coordinated changes of transcripts of more than 70 carbon-regulated genes and identified 2 genes (myo-inositol-1-phosphate synthase, a Kelch-domain protein) whose transcripts correlate with biomass. The impact of allelic variation at these 2 loci was shown by association mapping, identifying them as candidate lead genes with the potential to increase biomass production. PMID:19506259

Recreating the synthesis of starch granules in yeast

Science.gov (United States)

Pfister, Barbara; Sánchez-Ferrer, Antoni; Diaz, Ana; Lu, Kuanjen; Otto, Caroline; Holler, Mirko; Shaik, Farooque Razvi; Meier, Florence; Mezzenga, Raffaele; Zeeman, Samuel C

2016-01-01

Starch, as the major nutritional component of our staple crops and a feedstock for industry, is a vital plant product. It is composed of glucose polymers that form massive semi-crystalline granules. Its precise structure and composition determine its functionality and thus applications; however, there is no versatile model system allowing the relationships between the biosynthetic apparatus, glucan structure and properties to be explored. Here, we expressed the core Arabidopsis starch-biosynthesis pathway in Saccharomyces cerevisiae purged of its endogenous glycogen-metabolic enzymes. Systematic variation of the set of biosynthetic enzymes illustrated how each affects glucan structure and solubility. Expression of the complete set resulted in dense, insoluble granules with a starch-like semi-crystalline organization, demonstrating that this system indeed simulates starch biosynthesis. Thus, the yeast system has the potential to accelerate starch research and help create a holistic understanding of starch granule biosynthesis, providing a basis for the targeted biotechnological improvement of crops. DOI: http://dx.doi.org/10.7554/eLife.15552.001 PMID:27871361

Synthesis and properties of silane-fluoroacrylate grafted starch.

Science.gov (United States)

Qu, Jia; He, Ling

2013-10-15

The latex of silane-fluoroacrylate grafted starch for coating materials, VTMS-starch/P(MMA/BA/3FMA), is obtained by two step grafting reactions. Vinyltrimethoxysilane (VTMS) is primarily grafted onto starch by condensation between Si-OH and C-OH at 120 °C, and then the copolymer of methyl methacrylate (MMA), butyl acrylate (BA) and 2,2,2-trifluoroethyl methacrylate (3FMA) is grafted onto the VTMS-starch by emulsion polymerization. Fourier transform infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS) have been used to confirm the chemically grafting reactions in every step. The conversion percent, grafting percent and grafting efficiency for VTMS-starch/p(MMA/BA/3FMA) latex indicate that the optimum conditions should be controlled at 75 °C for 1h as VTMS-starch/P(MMA/BA/3FMA) in 1/3 weight ratio. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis have revealed that the latexes exhibit the uniform spherical particles of 40-60 nm in a narrow size distribution. The latex films perform the obvious hydrophobic (107°) property, lower surface free energy (25-35 mN/m) and the higher thermostability (330-440 °C) than starch (51°, 51.32 mN/m, 100-330 °C). Dynamic thermomechanical analysis (DMA) shows that the latex film could gain considerable toughness and strength with an elongation at break of 39.45% and a tensile strength of 11.97 MPa. Copyright © 2013 Elsevier Ltd. All rights reserved.

Starch as a source, starch as a sink: the bifunctional role of starch in carbon allocation.

Science.gov (United States)

MacNeill, Gregory J; Mehrpouyan, Sahar; Minow, Mark A A; Patterson, Jenelle A; Tetlow, Ian J; Emes, Michael J

2017-07-20

Starch commands a central role in the carbon budget of the majority of plants on earth, and its biological role changes during development and in response to the environment. Throughout the life of a plant, starch plays a dual role in carbon allocation, acting as both a source, releasing carbon reserves in leaves for growth and development, and as a sink, either as a dedicated starch store in its own right (in seeds and tubers), or as a temporary reserve of carbon contributing to sink strength, in organs such as flowers, fruits, and developing non-starchy seeds. The presence of starch in tissues and organs thus has a profound impact on the physiology of the growing plant as its synthesis and degradation governs the availability of free sugars, which in turn control various growth and developmental processes. This review attempts to summarize the large body of information currently available on starch metabolism and its relationship to wider aspects of carbon metabolism and plant nutrition. It highlights gaps in our knowledge and points to research areas that show promise for bioengineering and manipulation of starch metabolism in order to achieve more desirable phenotypes such as increased yield or plant biomass. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The regulation mechanisms of soluble starch and glycerol for production of azaphilone pigments in Monascus purpureus FAFU618 as revealed by comparative proteomic and transcriptional analyses.

Science.gov (United States)

Huang, Zi-Rui; Zhou, Wen-Bin; Yang, Xue-Ling; Tong, Ai-Jun; Hong, Jia-Li; Guo, Wei-Ling; Li, Tian-Tian; Jia, Rui-Bo; Pan, Yu-Yang; Lin, Jun; Lv, Xu-Cong; Liu, Bin

2018-04-01

Monascus spp. have been used for thousands of years as a traditional food additive in China. This mold can produce many different types of commercially valuable secondary metabolites of biological activity. Soluble starch and glycerol are the two principal carbon sources universally utilized by Monascus for the production of beneficial metabolites. In this study, the effects and regulation mechanisms of soluble starch and glycerol for M. purpureus FAFU618 on Monascus azaphilone pigments (MonAzPs) were investigated through ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-QTOF-MS/MS), comparative proteomics and quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR). The production of intracellular and extracellular pigments was significantly different between the soluble starch group (SSG) and glycerol group (GCG). Additionally, the components of intracellular pigments revealed by UPLC-QTOF-MS/MS showed that Monascin and Ankaflavin increased significantly in the GCG, while Rubropunctatin and Monascorubrin increased in the SSG. Differentially expressed proteins of mycelia between SSG and GCG were analyzed by two-dimensional gel electrophoresis (2-DE) and MALDI-TOF/TOF MS. We identified 27 proteins with statistically altered expression, of which 18 proteins associated with the EMP (glycolytic pathway), translation, energy generation, proteolysis, etc. were up-regulated, and 9 proteins, including ribosomal proteins, heat shock proteins (HSPs) and others, were down-regulated in GCG. Meanwhile, the expression levels of MonAzP biosynthetic genes were also analyzed by RT-qPCR, and the results showed that mppA, mppC, mppR1 and mppR2 were down-regulated, whereas genes MpPKS5, MpFasA2, MpFasB2, mppB, mppD and mppE were up-regulated. Collectively, these findings illustrate that the regulation of MonAzPs is not only closely related to the expression levels of certain proteins in the polyketide synthesis pathway

Starch and sucrose synthesis in Phaseolus vulgaris as affected by light, CO2, and abscisic acid

International Nuclear Information System (INIS)

Sharkey, T.D.; Berry, J.A.; Raschke, K.

1985-01-01

Phaseolus vulgaris L. leaves were subjected to various light, CO 2 , and O 2 levels and abscisic acid, then given a 10 minute pulse of 14 CO 2 followed by a 5 minute chase with unlabeled CO 2 . After the chase period, very little label remained in the ionic fractions except at low CO 2 partial pressure. Most label was found in the neutral, alcohol soluble fraction or in the insoluble fraction digestable by amyloglucosidase. Sucrose formation was linearly related to assimilation rate. Starch formation increased linearly with assimilation rate, but did not occur if the assimilation rate was below 4 micromoles per square meter per second. Neither abscisic acid, nor high CO 2 in combination with low O 2 caused significant perturbations of the sucrose/starch formation ratio. These studies indicate that the pathways for starch and sucrose synthesis both are controlled by the rate of net CO 2 assimilation, with sucrose the preferred product at very low assimilation rates

Synthesis of supermacroporous cryogel for bioreactors continuous starch hydrolysis.

Science.gov (United States)

Guilherme, Ederson Paulo Xavier; de Oliveira, Jocilane Pereira; de Carvalho, Lorendane Millena; Brandi, Igor Viana; Santos, Sérgio Henrique Sousa; de Carvalho, Gleidson Giordano Pinto; Cota, Junio; Mara Aparecida de Carvalho, Bruna

2017-11-01

A bioreactor was built by means of immobilizing alpha-amylase from Aspergillus oryzae by encapsulation, through cryopolymerization of acrylamide monomers for the continuous starch hydrolysis. The starch hydrolysis was evaluated regarding pH, the concentration of immobilized amylase on cryogel, the concentration of starch solution and temperature. The maximum value for starch hydrolysis was achieved at pH 5.0, concentration of immobilized enzyme 111.44 mg amylase /g cryogel , concentration of starch solution 45 g/L and temperature of 35°C. The immobilized enzyme showed a conversion ratio ranging from 68.2 to 97.37%, depending on the pH and temperature employed. Thus, our results suggest that the alpha-amylase from A. oryzae immobilized on cryogel monoliths represents a potential process for industrial production of maltose from starch hydrolysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Complementation of the amylose-free starch mutant of potato (Solanum tuberosum.) by the gene encoding granule-bound starch synthase

NARCIS (Netherlands)

van der Leij, E.R.; Visser, R.G.E.; OOSTERHAVEN, K; VANDERKOP, DAM; Jacobsen, E.; Feenstra, W.

1991-01-01

Agrobacterium rhizogenes-mediated introduction of the wild-type allele of the gene encoding granule-bound starch synthase (GBSS) into the amylose-free starch mutant amf of potato leads to restoration of GBSS activity and amylose synthesis, which demonstrates that Amf is the structural gene for GBSS.

Concerted suppression of all starch branching enzyme genes in barley produces amylose-only starch granules

DEFF Research Database (Denmark)

Carciofi, Massimiliano; Blennow, Per Gunnar Andreas; Jensen, Susanne Langgård

2012-01-01

is preferentially derived from amylose, which can be increased by suppressing amylopectin synthesis by silencing of starch branching enzymes (SBEs). However all the previous works attempting the production of high RS crops resulted in only partly increased amylose-content and/or significant yield loss. Results...... In this study we invented a new method for silencing of multiple genes. Using a chimeric RNAi hairpin we simultaneously suppressed all genes coding for starch branching enzymes (SBE I, SBE IIa, SBE IIb) in barley (Hordeum vulgare L.), resulting in production of amylose-only starch granules in the endosperm...... yield in a living organism. This was achieved by a new method of simultaneous suppression of the entire complement of genes encoding starch branching enzymes. We demonstrate that amylopectin is not essential for starch granule crystallinity and integrity. However the slower initial growth of shoots from...

The effect of laser repetition rate on the LASiS synthesis of biocompatible silver nanoparticles in aqueous starch solution

Directory of Open Access Journals (Sweden)

Zamiri R

2013-01-01

Full Text Available Reza Zamiri,1 Azmi Zakaria,1,* Hossein Abbastabar Ahangar,2 Majid Darroudi,3 Golnoosh Zamiri,1 Zahid Rizwan,1 Gregor PC Drummen4,* 1Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 2Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Selangor Darul Ehsan, Malaysia; 3Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 4Bionanoscience and Bio-Imaging Program, Cellular Stress and Ageing Program, Bio&Nano-Solutions, Düsseldorf, Germany*These authors contributed to this work equallyAbstract: Laser ablation-based nanoparticle synthesis in solution is rapidly becoming popular, particularly for potential biomedical and life science applications. This method promises one pot synthesis and concomitant bio-functionalization, is devoid of toxic chemicals, does not require complicated apparatus, can be combined with natural stabilizers, is directly biocompatible, and has high particle size uniformity. Size control and reduction is generally determined by the laser settings; that the size and size distribution scales with laser fluence is well described. Conversely, the effect of the laser repetition rate on the final nanoparticle product in laser ablation is less well-documented, especially in the presence of stabilizers. Here, the influence of the laser repetition rate during laser ablation synthesis of silver nanoparticles in the presence of starch as a stabilizer was investigated. The increment of the repetition rate does not negatively influence the ablation efficiency, but rather shows increased productivity, causes a red-shift in the plasmon resonance peak of the silver–starch nanoparticles, an increase in mean particle size and size distribution, and a distinct lack of agglomerate formation. Optimal results were achieved at 10 Hz repetition rate, with a mean particle size of ~10 nm and a

Size control synthesis of starch capped-gold nanoparticles

International Nuclear Information System (INIS)

Tajammul Hussain, S.; Iqbal, M.; Mazhar, M.

2009-01-01

Metallic gold nanoparticles have been synthesized by the reduction of chloroaurate anions [AuCl 4 ] - solution with hydrazine in the aqueous starch and ethylene glycol solution at room temperature and at atmospheric pressure. The characterization of synthesized gold nanoparticles by UV-vis spectroscopy, high resolution transmission electron microscopy (HRTEM), electron diffraction analysis, X-ray diffraction (XRD), and X-rays photoelectron spectroscopy (XPS) indicate that average size of pure gold nanoparticles is 3.5 nm, they are spherical in shape and are pure metallic gold. The concentration effects of [AuCl 4 ] - anions, starch, ethylene glycol, and hydrazine, on particle size, were investigated, and the stabilization mechanism of Au nanoparticles by starch polymer molecules was also studied by FT-IR and thermogravimetric analysis (TGA). FT-IR and TGA analysis shows that hydroxyl groups of starch are responsible of capping and stabilizing gold nanoparticles. The UV-vis spectrum of these samples shows that there is blue shift in surface plasmon resonance peak with decrease in particle size due to the quantum confinement effect, a supporting evidence of formation of gold nanoparticles and this shift remains stable even after 3 months.

In situ biomimetic synthesis, characterization and in vitro investigation of bone-like nanohydroxyapatite in starch matrix

Energy Technology Data Exchange (ETDEWEB)

Sadjadi, M.S., E-mail: msadjad@gmail.com [Department of Chemistry, Science and Research Branch, Islamic Azad University, Poonak, Tehran (Iran, Islamic Republic of); Meskinfam, M. [Department of Chemistry, Science and Research Branch, Islamic Azad University, Poonak, Tehran (Iran, Islamic Republic of); Sadeghi, B. [Department of Chemistry, Tonekabon Branch, Islamic Azad university, Tonekabon (Iran, Islamic Republic of); Jazdarreh, H. [Department of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Zare, K. [Department of Chemistry, Faculty of Science, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

2010-11-01

In this work, we report the synthesis of bone-like hydroxyapatite (HAp) nanorods in wheat starch matrix via a biomimetic process. Characterization of the samples was performed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Scanning and transmission electron microscopy (SEM and TEM) were used to determine the size, shape and morphology of nano-HAp. The results indicate that, the shape and morphology of nHAp is influenced by the presence of starch as a template agent and rod-like nHAp similar to the inorganic component in the human body is obtained at room temperature. In vitro bioactivity of the synthesized HAp nanocomposites was finally verified by comparison of the HAp's structures and morphology before and after immersion in simulated body fluid (SBF) solution for 3, 7, and 14 days.

Starch-assisted synthesis and optical properties of ZnS nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Tian, Xiuying, E-mail: xiuyingt@yahoo.com; Wen, Jin; Wang, Shumei; Hu, Jilin; Li, Jing; Peng, Hongxia

2016-05-15

Highlights: • ZnS spherical nanostructure was prepared via starch-assisted method. • The crystalline lattice structure, morphologies, chemical and optical properties of ZnS nanoparticles. • The forming mechanism of ZnS nanoparticles. • ZnS spherical nano-structure can show blue emission at 460–500 nm. - Abstract: ZnS nanoparticles are fabricated via starch-assisted method. The effects of different starch amounts on structure and properties of samples are investigated, and the forming mechanism of ZnS nanoparticles is discussed. By X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–vis) spectroscopy and fluorescence (FL) spectrometer, their phases, crystalline lattice structure, morphologies, chemical and optical properties are characterized. The results show that ZnS has polycrystalline spherical structure with the mean diameter of 130 nm. Sample without starch reveals irregular aggregates with particle size distribution of 0.5–2 μm. The band gap value of ZnS is 3.97 eV. The chemical interaction exists between starch molecules and ZnS nanoparticles by hydrogen bonds. The stronger FL emission peaks of ZnS synthesized with starch, indicate a larger content of sulfur vacancies or defects than ZnS synthesized without starch.

Starch-assisted synthesis and optical properties of ZnS nanoparticles

International Nuclear Information System (INIS)

Tian, Xiuying; Wen, Jin; Wang, Shumei; Hu, Jilin; Li, Jing; Peng, Hongxia

2016-01-01

Highlights: • ZnS spherical nanostructure was prepared via starch-assisted method. • The crystalline lattice structure, morphologies, chemical and optical properties of ZnS nanoparticles. • The forming mechanism of ZnS nanoparticles. • ZnS spherical nano-structure can show blue emission at 460–500 nm. - Abstract: ZnS nanoparticles are fabricated via starch-assisted method. The effects of different starch amounts on structure and properties of samples are investigated, and the forming mechanism of ZnS nanoparticles is discussed. By X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–vis) spectroscopy and fluorescence (FL) spectrometer, their phases, crystalline lattice structure, morphologies, chemical and optical properties are characterized. The results show that ZnS has polycrystalline spherical structure with the mean diameter of 130 nm. Sample without starch reveals irregular aggregates with particle size distribution of 0.5–2 μm. The band gap value of ZnS is 3.97 eV. The chemical interaction exists between starch molecules and ZnS nanoparticles by hydrogen bonds. The stronger FL emission peaks of ZnS synthesized with starch, indicate a larger content of sulfur vacancies or defects than ZnS synthesized without starch.

Maltase-glucoamylase: Mucosal regulator of prandial starch glucogenesis and complementary hepatic gluconeogenesis of mice

Science.gov (United States)

It was hypothesized that the slower rate of starch digestion by residual sucraseisomaltase (Si) maltase failed to fully regulate gluconeogenesis. In the present study the rate of gluconeogenesis was measured directly (J Appl Physiol 104: 944-951, 2008) and compared with exogenous glucose derived fro...

Synthesis and Characterization of PVP-Grafted-Starch Hydrogels Using Gamma Radiation

International Nuclear Information System (INIS)

Suwanmala, Phiriyatorn; Hemvichian, Kasinee; Sonsuk, Manit

2004-10-01

A Series of hydrogels were prepared from gelatinized cassava starch and vinylpyrrolidone by radiation-induced graft copolymerization. Gel fraction, swelling ratio and gel strength of the obtained hydrogels were characterized. The experimental results show that the swelling ratio is inversely dependent on the radiation dose. The results from PVP-grafted-starch were subsequently compared with those of PVP hydrogels and PVP-blended-starch hydrogels. It was found that the PVP-grafted-starch hydrogels, with gel fraction higher than 80% can be prepared at the dose of 10 kGy, while PVP and PVP-blended-starch hydrogels require at least 30 kGy to obtain gels with more than 80% gel fraction

Synthesis of graft copolymers onto starch and its semiconducting properties

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Nevin Çankaya

Full Text Available Literature review has revealed that, although there are studies about grafting on natural polymers, especially on starch, few of them are about electrical properties of graft polymers. Starch methacrylate (St.met was obtained by esterification of OH groups on natural starch polymer for this purpose. Grafting of synthesized N-cyclohexyl acrylamide (NCA and commercial methyl methacrylate (MMA monomers with St.met was done by free radical polymerization method. The graft copolymers were characterized with FT-IR spectra, thermal and elemental analysis. Thermal stabilities of the graft copolymers were determined by TGA (thermo gravimetric analysis method and thermal stability of the copolymers is decreased via grafting. The electrical conductivity of the polymers was measured as a function of temperature and it has been observed that electrical conductivity increases with increasing temperature. The absorbance and transmittance versus wavelength of the polymers have been measured. Keywords: Starch, Graft copolymer, Semiconducting, Thermal stability, Starch methacrylate

Facile Synthesis of Curcumin-Loaded Starch-Maleate Nanoparticles

OpenAIRE

Suh Cem Pang; Soon Hiang Tay; Suk Fun Chin

2014-01-01

We have demonstrated the loading of curcumin onto starch maleate (SM) under mild conditions by mixing dissolved curcumin and SM nanoparticles separately in absolute ethanol and ethanol/aqueous (40 : 60 v/v), respectively. Curcumin-loaded starch-maleate (CurSM) nanoparticles were subsequently precipitated from a homogeneous mixture of these solutions in absolute ethanol based on the solvent exchange method. TEM analysis indicated that the diameters of CurSM nanoparticles were ranged between 30...

Effects of replacing dietary starch with neutral detergent-soluble fibre on ruminal fermentation, microbial synthesis and populations of ruminal cellulolytic bacteria using the rumen simulation technique (RUSITEC).

Science.gov (United States)

Zhao, X H; Liu, C J; Liu, Y; Li, C Y; Yao, J H

2013-12-01

A rumen simulation technique (RUSITEC) apparatus with eight 800 ml fermenters was used to investigate the effects of replacing dietary starch with neutral detergent-soluble fibre (NDSF) by inclusion of sugar beet pulp in diets on ruminal fermentation, microbial synthesis and populations of ruminal cellulolytic bacteria. Experimental diets contained 12.7, 16.4, 20.1 or 23.8% NDSF substituted for starch on a dry matter basis. The experiment was conducted over two independent 15-day incubation periods with the last 8 days used for data collection. There was a tendency that 16.4% NDSF in the diet increased the apparent disappearance of organic matter (OM) and neutral detergent fibre (NDF). Increasing dietary NDSF level increased carboxymethylcellulase and xylanase activity in the solid fraction and apparent disappearance of acid detergent fibre (ADF) but reduced the 16S rDNA copy numbers of Ruminococcus albus in both liquid and solid fractions and R. flavefaciens in the solid fraction. The apparent disappearance of dietary nitrogen (N) was reduced by 29.6% with increased dietary NDSF. Substituting NDSF for starch appeared to increase the ratios of acetate/propionate and methane/volatile fatty acids (VFA) (mol/mol). Replacing dietary starch with NDSF reduced the daily production of ammonia-N and increased the growth of the solid-associated microbial pellets (SAM). Total microbial N flow and efficiency of microbial synthesis (EMS), expressed as g microbial N/kg OM fermented, tended to increase with increased dietary NDSF, but the numerical increase did not continue as dietary NDSF exceeded 20.1% of diet DM. Results suggested that substituting NDSF for starch up to 16.4% of diet DM increased digestion of nutrients (except for N) and microbial synthesis, and further increases (from 16.4% to 23.8%) in dietary NDSF did not repress microbial synthesis but did significantly reduce digestion of dietary N. © 2012 Blackwell Verlag GmbH.

The regulation of starch accumulation in Panicum maximum Jacq ...

African Journals Online (AJOL)

... decrease the starch level. These observations are discussed in relation to the photosynthetic characteristics of P. maximum. Keywords: accumulation; botany; carbon assimilation; co2 fixation; growth conditions; mesophyll; metabolites; nitrogen; nitrogen levels; nitrogen supply; panicum maximum; plant physiology; starch; ...

Structure, function and regulation of the enzymes in the starch biosynthetic pathway.

Energy Technology Data Exchange (ETDEWEB)

Geiger, Jim

2013-11-30

Starch is the major reserve polysaccharide in nature and accounts for the majority of the caloric intact of humans. It is also gaining importance as a renewable and biodegradable industrial material. There is burgeoning interest in increasing the amount and altering the properties of the plant starches by plant genetic modification. A rational approach to this effort will require a detailed, atomic-level understanding of the enzymatic processes that produce the starch granule. The starch granule is a complex particle made up of alternating layers of crystalline and amorphous lamellae. It consists of two types of polymer, amylose, a polymer of relatively long chains of α-1,4-linked glucans that contain virtually no branches, and amylopectin, which is highly branched and contains much shorter chains. This complex structure is synthesized by the coordinate activities of the starch synthases (SS), which elongate the polysaccharide chain by addition of glucose units via α-1,4 linkages using ADP- glucose as a donor, and branching enzymes (BE), which branch the polysaccharide chain by cleavage of α₋1,4 linkages and subsequent re-attachment via α₋1,6 linkages. Several isoforms of both starch synthase (SS) and branching enzyme (BE) are found in plants, including SSI, SSII, SSIII and granule- bound SS (GBSS), and SBEI, SBEIIa and SBEIIb. These isoforms have different activities and substrate and product specificities and play different roles in creating the granule and determining the properties of the resulting starch. The overarching goal of this proposal is to begin to understand the regulation and specificities of these enzymes at the atomic level. High-resolution X-ray structures of these enzymes bound to substrates and products will be determined to visualize the molecular interactions responsible for the properties of the enzymes. Hypotheses regarding these issues will then be tested using mutagenesis and enzyme assays. To date, we have determined the

In vivo phosphoproteome characterization reveals key starch granule-binding phosphoproteins involved in wheat water-deficit response.

Science.gov (United States)

Chen, Guan-Xing; Zhen, Shou-Min; Liu, Yan-Lin; Yan, Xing; Zhang, Ming; Yan, Yue-Ming

2017-10-23

Drought stress during grain development causes significant yield loss in cereal production. The phosphorylated modification of starch granule-binding proteins (SGBPs) is an important mechanism regulating wheat starch biosynthesis. In this study, we performed the first proteomics and phosphoproteomics analyses of SGBPs in elite Chinese bread wheat (Triticum aestivum L.) cultivar Jingdong 17 under well-watered and water-stress conditions. Water stress treatment caused significant reductions in spike grain numbers and weight, total starch and amylopectin content, and grain yield. Two-dimensional gel electrophoresis revealed that the quantity of SGBPs was reduced significantly by water-deficit treatment. Phosphoproteome characterization of SGBPs under water-deficit treatment demonstrated a reduced level of phosphorylation of main starch synthesis enzymes, particularly for granule-bound starch synthase (GBSS I), starch synthase II-a (SS II-a), and starch synthase III (SS III). Specifically, the Ser34 site of the GBSSI protein, the Tyr358 site of SS II-a, and the Ser837 site of SS III-a exhibited significant less phosphorylation under water-deficit treatment than well-watered treatment. Furthermore, the expression levels of several key genes related with starch biosynthesis detected by qRT-PCR were decreased significantly at 15 days post-anthesis under water-deficit treatment. Immunolocalization showed a clear movement of GBSS I from the periphery to the interior of starch granules during grain development, under both water-deficit and well-watered conditions. Our results demonstrated that the reduction in gene expression or transcription level, protein expression and phosphorylation levels of starch biosynthesis related enzymes under water-deficit conditions is responsible for the significant decrease in total starch content and grain yield.

Synthesis, characterization and properties of radiation-induced Starch/(EG-co-MAA hydrogels

Directory of Open Access Journals (Sweden)

H.L. Abd El-Mohdy

2016-11-01

Full Text Available Association of poly(carboxylic acids and non-ionic polymers in solutions via hydrogen bonding results in formation of novel polymeric materials–interpolymer complexes. Starch/(EG-co-MAA polymeric hydrogels were obtained by γ-initiated radiation copolymerization of ethylene glycol (EG with methacrylic acid (MAA which grafted on starch. The gel content of prepared hydrogels was varied with changes in starch content, EG:MAA composition and irradiation dose as well as crosslinking density. The swelling was studied as a function of starch content, EG:MAA composition, irradiation dose, type of soaked liquid, pH and temperature of matrix-surrounding medium. The degree of swelling greatly increased with enhanced MAA content, pH and temperature whereas, it decreased with reduced starch content and irradiation dose. The swelling was varied with the polarity of soaked liquid. The results showed that Starch/(EG-co-MAA hydrogels reached the equilibrium swelling state in water after 72 h. The structure and surface morphology of prepared polymer were confirmed with FTIR and SEM, respectively. The thermal properties of hydrogels were studied by using DSC and TGA, they cleared that there is miscibility between EG and MAA in copolymer and adding them improve the thermal stability of starch. The results indicate that Starch/(EG-co-MAA materials may be used in various applications.

Sugar uptake and starch biosynthesis by slices of developing maize endosperm

International Nuclear Information System (INIS)

Felker, F.C.; Liu, Kangchien; Shannon, J.C.

1990-01-01

14 C-Sugar uptake and incorporation into starch by slices of developing maize (Zea mays L.) endosperm were examined and compared with sugar uptake by maize endosperm-derived suspension cultures. Rates of sucrose, fructose, and D- and L-glucose uptake by slices were similar, whereas uptake rates for these sugars differed greatly in suspension cultures. Concentration dependence of sucrose, fructose, and D-glucose uptake was biphasic (consisting of linear plus saturable components) with suspension cultures but linear with slices. These and other differences suggest that endosperm slices are freely permeable to sugars. After diffusion into the slices, sugars were metabolized and incorporated into starch. Starch synthesis, but not sugar accumulation, was greatly reduced by 2.5 millimolar p-chloromercuribenzenesulfonic acid and 0.1 millimolar carbonyl cyanide m-chlorophenylhydrazone. Starch synthesis was dependent on kernel age and incubation temperature, but not on external pH (5 through 8). Competing sugars generally did not affect the distribution of 14 C among the soluble sugars extracted from endosperm slices incubated in 14 C-sugars. Competing hexoses reduced the incorporation of 14 C into starch, but competing sucrose did not, suggesting that sucrose is not a necessary intermediate in starch biosynthesis. The bidirectional permeability of endosperm slices to sugars makes the characterization of sugar transport into endosperm slices impossible, however the model system is useful for experiments dealing with starch biosynthesis which occurs in the metabolically active tissue

SYNTHESIS AND CHARACTERIZATION OF BIODEGRDABLE PLASTIC FROM CASAVA STARCH AND ALOE VERA EXTRACT WITH GLYCEROL PLASTICIZER

Directory of Open Access Journals (Sweden)

Mery Apriyani

2016-05-01

Full Text Available Synthesis and characterizations of Biodegradable Plastic made of Cassava Waste Starch, glycerol, acetic acid and Aloe vera extract has done. The aims of this research are to study the influence of addition of aloe vera extract in plastics mechanics properties, water vapor transmission rate and biodegradation. There are five main steps in this research, extraction of aloe vera, cassava starch preparation from cassava waste, preparations, characterization and biodegradability study of biodegradable plastic. The addition variations of aloe vera extract that used in this research are 0.01; 0.03; 0.05; 0.07 and 0.14 grams. Results showed that the addition of aloe Vera tends to increased biodegrable plastic thickness to 0.01 mm and elongation to 32.07%. However, biodegradable plastic tensile strength tends to decreased to 23.95 Mpa. Optimum tensile strength is 3.90 Mpa and elongation is 34.43%. Optimum water vapor transmission rate is 2.40 g/m2hours. Biodegradation study of biodegradable plastic showed that addition of aloe vera extract doesn’t significantly influence in plastic degradations.

Synthesis and Characterization of Polyethylene/Starch Nanocomposites: A Spherical Starch-Supported Catalyst and In Situ Ethylene Polymerization.

Science.gov (United States)

Zhanga, Hao; Xi, Shixia; Wang, Shuwei; Liu, Jingsheng; Yoon, Keun-Byoung; Lee, Dong-Ho; Zhang, Hexin; Zhang, Xuequan

2017-01-01

In the present article, a novel spherical starch-supported vanadium (V)-based Ziegler-Natta catalyst was synthesized. The active centers of the obtained catalyst well dispersed in the starch through the SEM-EDX analysis. The effects of reaction conditions on ethylene polymerization were studied. The synthesized catalyst exhibited high activity toward ethylene polymerization in the presence of ethylaluminium sesquichloride (EASC) cocatalyst. Interestingly, the fiber shape PE was obtained directly during the polymerization process.

The priming of storage glucan synthesis from bacteria to plants: current knowledge and new developments.

Science.gov (United States)

D'Hulst, Christophe; Mérida, Angel

2010-10-01

Starch is the main polymer in which carbon and energy are stored in land plants, algae and some cyanobacteria. It plays a crucial role in the physiology of these organisms and also represents an important polymer for humans, in terms of both diet and nonfood industry uses. Recent efforts have elucidated most of the steps involved in the synthesis of starch. However, the process that initiates the synthesis of the starch granule remains unclear. Here, we outline the similarities between the synthesis of starch and the synthesis of glycogen, the other widespread and abundant glucose-based polymer in living cells. We place special emphasis on the mechanisms of initiation of the glycogen granule and current knowledge concerning the initiation of the starch granule. We also discuss recent discoveries regarding the function of starch synthases in the priming of the starch granule and possible interactions with other elements of the starch synthesis machinery.

New perspectives of starch: Synthesis and in vitro assessment of novel thiolated mucoadhesive derivatives.

Science.gov (United States)

Jelkmann, Max; Bonengel, Sonja; Menzel, Claudia; Markovic, Svetislav; Bernkop-Schnürch, Andreas

2018-05-11

The purpose of this study was to develop a novel thiolated starch polymer with improved mucoadhesive properties by conjugation of cysteamine to starch as a natural polymer of restricted mucoadhesive properties. Aldehyde substructures were integrated into starch via oxidative cleavage of vicinal diols by increasing amounts of sodium periodate followed by covalent attachment of cysteamine to oxidized starch via reductive amination. Thiol groups were quantified via Ellman's reaction and their impact on mucoadhesion was analyzed by rheological investigations, the rotating cylinder method and tensile studies on porcine mucosa. The total amount of immobilized thiol groups revealed a correlation between degree of oxidation and thiolation. Modified starch demonstrated an up to 1.66-fold increase in water uptake in comparison to native starch. Modification of starch resulted in greatly improved cohesive properties and improvement in mucoadhesion. Rheological investigations revealed a 2- to 4-fold rise in viscosity of mucus. Tensile studies revealed a linear correlation between degree of oxidation/thiolation and enhancement of maximum detachment force and total work adhesion. In terms of these results, thiolated starch is a new, promising, polymer in the field of mucoadhesive drug delivery systems. Copyright © 2018 Elsevier B.V. All rights reserved.

'Green' synthesis of starch capped CdSe nanoparticles at room temperature

International Nuclear Information System (INIS)

Li Jinhua; Ren Cuiling; Liu Xiaoyan; Hu Zhide; Xue Desheng

2007-01-01

The nearly monodisperse starch capped CdSe nanoparticles were successfully synthesized by a simple and 'green' route at room temperature. The as-prepared nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), UV-vis absorption and photoluminescence (PL) spectra. The XRD analysis showed that the starch capped CdSe nanoparticles were of the cubic structure, the average particle size was calculated to be about 3 nm according to the Debye-Scherrer equation. TEM micrographs exhibited that the starch capped CdSe nanoparticles were well dispersed than the uncapped CdSe nanoparticles, the mean particles size of the capped CdSe was about 3 nm in the TEM image, which was in good agreement with the XRD

Barley callus: a model system for bioengineering of starch in cereals

DEFF Research Database (Denmark)

Carciofi, Massimiliano; Blennow, Per Gunnar Andreas; Nielsen, Morten M

2012-01-01

. In this way starch is adapted to a variety of specific end-uses. Recombinant DNA technologies offers an alternative to starch industrial processing. The plant biosynthetic pathway can be manipulated to design starches with novel structure and improved technological properties. In the future this may reduce...... or eliminate the economical and environmental costs of industrial modification. Recently, many advances have been achieved to clarify the genetic mechanism that controls starch biosynthesis. Several genes involved in the synthesis and modification of complex carbohydrates in many organisms have been identified...... and cloned. This knowledge suggests a number of strategies and a series of candidate genes for genetic transformation of crops to generate new types of starch-based polymers. However transformation of cereals is a slow process and there is no easy model system available to test the efficiency of candidate...

Oligosaccharide and Substrate Binding in the Starch Debranching Enzyme Barley Limit Dextrinase

DEFF Research Database (Denmark)

Møller, Marie Sofie; Windahl, Michael Skovbo; Sim, Lyann

2015-01-01

Complete hydrolytic degradation of starch requires hydrolysis of both the α-1,4- and α-1,6-glucosidic bonds in amylopectin. Limit dextrinase (LD) is the only endogenous barley enzyme capable of hydrolyzing the α-1,6-glucosidic bond during seed germination, and impaired LD activity inevitably...... reduces the maltose and glucose yields from starch degradation. Crystal structures of barley LD and active-site mutants with natural substrates, products and substrate analogues were sought to better understand the facets of LD-substrate interactions that αconfine high activity of LD to branched...... starch synthesis....

Photosynthesis down-regulation precedes carbohydrate accumulation under sink limitation in Citrus.

Science.gov (United States)

Nebauer, Sergio G; Renau-Morata, Begoña; Guardiola, José Luis; Molina, Rosa-Victoria

2011-02-01

Photosynthesis down-regulation due to an imbalance between sources and sinks in Citrus leaves could be mediated by excessive accumulation of carbohydrates. However, there is limited understanding of the physiological role of soluble and insoluble carbohydrates in photosynthesis regulation and the elements triggering the down-regulation process. In this work, the role of non-structural carbohydrates in the regulation of photosynthesis under a broad spectrum of source-sink relationships has been investigated in the Salustiana sweet orange. Soluble sugar and starch accumulation in leaves, induced by girdling experiments, did not induce down-regulation of the photosynthetic rate in the presence of sinks (fruits). The leaf-to-fruit ratio did not modulate photosynthesis but allocation of photoassimilates to the fruits. The lack of strong sink activity led to a decrease in the photosynthetic rate and starch accumulation in leaves. However, photosynthesis down-regulation due to an excess of total soluble sugars or starch was discarded because photosynthesis and stomatal conductance reduction occurred prior to any significant accumulation of these carbohydrates. Gas exchange and fluorescence parameters suggested biochemical limitations to photosynthesis. In addition, the expression of carbon metabolism-related genes was altered within 24 h when strong sinks were removed. Sucrose synthesis and export genes were inhibited, whereas the expression of ADP-glucose pyrophosphorylase was increased to cope with the excess of assimilates. In conclusion, changes in starch and soluble sugar turnover, but not sugar content per se, could provide the signal for photosynthesis regulation. In these conditions, non-stomatal limitations strongly inhibited the photosynthetic rate prior to any significant increase in carbohydrate levels.

Preparation and characterization of dialdehyde starch by one-step acid hydrolysis and oxidation.

Science.gov (United States)

Zuo, Yingfeng; Liu, Wenjie; Xiao, Junhua; Zhao, Xing; Zhu, Ying; Wu, Yiqiang

2017-10-01

Dialdehyde starch was prepared by one-step synthesis of acid hydrolysis and oxidation, using corn starch as the raw material, sodium periodate (NaIO 4 ) as the oxidant, and hydrochloric acid (HCl) as the acid solution. The prepared dialdehyde starch was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC). The results confirmed that oxidation occurred between the starch and NaIO 4 . The acid hydrolysis reaction reduced the molecular weight of starch and effectively improved the aldehyde group contents (92.7%). Scanning electron microscope (SEM) analysis indicated that the average particle size decreased after acid hydrolysis and oxidation reaction. X-ray diffraction (XRD) and thermal gravimetric analyzer (TGA) analysis demonstrated that the crystallinity of the obtained dialdehyde starch showed a downward trend and a decelerated thermal decomposition rate. The starch after acid hydrolysis and oxidation exhibited lower hot paste viscosity and higher reactivity. Copyright © 2017. Published by Elsevier B.V.

Synthesis, characterization, release kinetics and toxicity profile of drug-loaded starch nanoparticles.

Science.gov (United States)

El-Naggar, Mehrez E; El-Rafie, M H; El-sheikh, M A; El-Feky, Gina S; Hebeish, A

2015-11-01

The current research work focuses on the medical application of the cost-effective cross-linked starch nanoparticles, for the transdermal delivery using Diclofenac sodium (DS) as a model drug. The prepared DS-cross-linked starch nanoparticles were synthesized using nanoprecipitation technique at different concentrations of sodium tripolyphosphate (STPP) in the presence of Tween 80 as a surfactant. The resultant cross-linked starch nanoparticles loaded with DS were characterized using world-class facilities such as TEM, DLS, FT-IR, XRD, and DSc. The efficiency of DS loading was also evaluated via entrapment efficiency as well as in vitro release and histopathological study on rat skin. The optimum nanoparticles formulation selected by the JMP(®) software was the formula that composed of 5% maize starch, 57.7mg DS and 0.5% STPP and 0.4% Tween 80, with particle diameter of about 21.04nm, polydispersity index of 0.2 and zeta potential of -35.3mV. It is also worth noting that this selected formula shows an average entrapment efficiency of 95.01 and sustained DS release up to 6h. The histophathological studies using the best formula on rat skin advocate the use of designed transdermal DS loaded cross-linked starch nanoparticles as it is safe and non-irritant to rat skin. The overall results indicate that, the starch nanoparticles could be considered as a good carrier for DS drug regarding the enhancement in its controlled release and successful permeation, thus, offering a promising nanoparticulate system for the transdermal delivery non-steroidal anti-inflammatory drug (NSAID). Copyright © 2015 Elsevier B.V. All rights reserved.

Starch bioengineering

DEFF Research Database (Denmark)

Blennow, Andreas

2018-01-01

Application of starch in industry frequently requires extensive modification. This is usually achieved by chemical and/or physical modification that is time-consuming and often expensive and polluting. To impart functionality as early as possible in the starch production chain, modification can...... be achieved directly as part of the developing starch storage roots, tubers, and seeds and grains of the crop. Starch has been a strong driver for human development and is now the most important energy provider in the diet forcing the development of novel and valuable starch qualities for specific...... applications. Among the most important structures that can be targeted include starch phosphorylation chain transfer/branching generating chemically substituted and chain length-modified starches such as resistant and health-promoting high-amylose starch. Starch bioengineering has been employed for more than...

Characterization of Function of the GlgA2 Glycogen/Starch Synthase in Cyanobacterium sp. Clg1 Highlights Convergent Evolution of Glycogen Metabolism into Starch Granule Aggregation.

Science.gov (United States)

Kadouche, Derifa; Ducatez, Mathieu; Cenci, Ugo; Tirtiaux, Catherine; Suzuki, Eiji; Nakamura, Yasunori; Putaux, Jean-Luc; Terrasson, Amandine Durand; Diaz-Troya, Sandra; Florencio, Francisco Javier; Arias, Maria Cecilia; Striebeck, Alexander; Palcic, Monica; Ball, Steven G; Colleoni, Christophe

2016-07-01

At variance with the starch-accumulating plants and most of the glycogen-accumulating cyanobacteria, Cyanobacterium sp. CLg1 synthesizes both glycogen and starch. We now report the selection of a starchless mutant of this cyanobacterium that retains wild-type amounts of glycogen. Unlike other mutants of this type found in plants and cyanobacteria, this mutant proved to be selectively defective for one of the two types of glycogen/starch synthase: GlgA2. This enzyme is phylogenetically related to the previously reported SSIII/SSIV starch synthase that is thought to be involved in starch granule seeding in plants. This suggests that, in addition to the selective polysaccharide debranching demonstrated to be responsible for starch rather than glycogen synthesis, the nature and properties of the elongation enzyme define a novel determinant of starch versus glycogen accumulation. We show that the phylogenies of GlgA2 and of 16S ribosomal RNA display significant congruence. This suggests that this enzyme evolved together with cyanobacteria when they diversified over 2 billion years ago. However, cyanobacteria can be ruled out as direct progenitors of the SSIII/SSIV ancestral gene found in Archaeplastida. Hence, both cyanobacteria and plants recruited similar enzymes independently to perform analogous tasks, further emphasizing the importance of convergent evolution in the appearance of starch from a preexisting glycogen metabolism network. © 2016 American Society of Plant Biologists. All Rights Reserved.

Bioindicative values of microfungi in starch and possible deficiencies of the new Serbian regulation on food hygiene

Directory of Open Access Journals (Sweden)

Uzelac Ema D.

2013-01-01

Full Text Available The results of tests on the presence of yeasts and molds in cornstarch [AD ‘IPOK’ Zrenjanin, 2007-2008, made at the time when previous Regulations were valid] were analyzed in terms of bioindicative values of microfungi as indicators of quality and safety of raw material or final food products. Microbiological analysis was used to detect the presence of a number of microorganisms MMI-0001, and a questionnaire was designed at the Department of Public Health in Zrenjanin town (Republic of Serbia, where the anal­yses were done, regarding the microbiological tests on starch. In order to rationalize the analyses and make them more economical, several areas of product quality control (water, food, raw materials, space were recommended either to be excluded or regarded as optional. Thus, analysis of presence of microfungi as indicators of product quality was categorized as optional. The results obtained from this research suggest a different conclusion because the bacteria in the samples indicated ˮmicrobiologically“, namely bacteriologically, safe samples of food, while, on the contrary, the presence of some microfungi as distinct xerophilous or xerotolerant microorganisms, indicated that the food was mycologically non-safe. The obtained data are crucial for questioning the decision to exclude the earlier required (mycological analysis of the samples (in the production of starch, or end products, etc. and categorize such analyses in new Regulations as optional, depending on the manufacturer’s preference. Bioindicative values of microfungi as indicators of the quality of starch, clearly point to the shortsightedness of the new Regulations on food hygiene and safety, where tests on certain microorganisms (in this case, yeasts and molds are not legally defined as mandatory, but the Law leaves manufacturers a possibility to choose (or not to choose the testing and frequency of testing on the presence (absence of microorganisms, which can be

Characterization of Function of the GlgA2 Glycogen/Starch Synthase in Cyanobacterium sp. Clg1 Highlights Convergent Evolution of Glycogen Metabolism into Starch Granule Aggregation1

Science.gov (United States)

Kadouche, Derifa; Arias, Maria Cecilia

2016-01-01

At variance with the starch-accumulating plants and most of the glycogen-accumulating cyanobacteria, Cyanobacterium sp. CLg1 synthesizes both glycogen and starch. We now report the selection of a starchless mutant of this cyanobacterium that retains wild-type amounts of glycogen. Unlike other mutants of this type found in plants and cyanobacteria, this mutant proved to be selectively defective for one of the two types of glycogen/starch synthase: GlgA2. This enzyme is phylogenetically related to the previously reported SSIII/SSIV starch synthase that is thought to be involved in starch granule seeding in plants. This suggests that, in addition to the selective polysaccharide debranching demonstrated to be responsible for starch rather than glycogen synthesis, the nature and properties of the elongation enzyme define a novel determinant of starch versus glycogen accumulation. We show that the phylogenies of GlgA2 and of 16S ribosomal RNA display significant congruence. This suggests that this enzyme evolved together with cyanobacteria when they diversified over 2 billion years ago. However, cyanobacteria can be ruled out as direct progenitors of the SSIII/SSIV ancestral gene found in Archaeplastida. Hence, both cyanobacteria and plants recruited similar enzymes independently to perform analogous tasks, further emphasizing the importance of convergent evolution in the appearance of starch from a preexisting glycogen metabolism network. PMID:27208262

Synthesis of Potato Starch-Acrylic-Acid Hydrogels by Gamma Radiation and Their Application in Dye Adsorption

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Md. Murshed Bhuyan

2016-01-01

Full Text Available Several kinds of acrylic-acid-grafted-starch (starch/AAc hydrogels were prepared at room temperature (27°C by applying 5, 10, 15, 20, and 25 kGy of gamma radiation to 15% AAc aqueous solutions containing 5, 7.5, and 15% of starch. With increment of the radiation dose, gel fraction became higher and attained the maximum (96.5% at 15 kGy, above which the fraction got lowered. On the other hand, the gel fraction monotonically increased with the starch content. Swelling ratios were lower for the starch/AAc hydrogels prepared with higher gamma-ray doses and so with larger starch contents. Significant promotions of the swelling ratios were demonstrated by hydrolysis with NaOH: 13632±10% for 15 kGy radiation-dosed [5% starch/15% AAc] hydrogel, while the maximum swelling ratio was ~200% for those without the treatment. The authors further investigated the availability of the starch/AAc hydrogel as an adsorbent recovering dye waste from the industrial effluents by adopting methylene blue as a model material; the hydrogels showed high dye-capturing coefficients which increase with the starch ratio. The optimum dye adsorption was found to be 576 mg per g of the hydrogel having 7.5 starch and 15% AAc composition. Two kinetic models, (i pseudo-first-order and (ii pseudo-second-order kinetic models, were applied to test the experimental data. The latter provided the best correlation of the experimental data compared to the pseudo-first-order model.

DEVELOPMENT OF ADHESIVE TO THE BASIS OF CORN AND CASSAVA STARCH

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Rosane Furtado Fabrício

2014-05-01

Full Text Available Corn and native cassava starch were modified by oxidation and acid hydrolysis, aiming to develop paper and paperboard stickers. The oxidation was made with Sodium hypochlorite (NaOCl in two distinct concentrations of active chloride which is present on oxidizing agent solution. The synthesis resulting products were used to make stickers and they were compared to corn and cassava starch based stickers without any modification, as well as commercial stickers based on polyvinyl acetate (PVA. Two different methodologies were tested using acid hydrolysis to modify corn and cassava starch, both using phosphoric acid (H3PO4 in order to obtain dextrin and subsequently use it in the production of stickers and also comparing them to petrochemical-based commercial stickers. Considering the different starch modifications methods (oxidation and acid hydrolysis, stickers based on renewable raw material were obtained, which combine biodegradability, low costs and availability.

Molecular Regulation of Histamine Synthesis

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Hua Huang

2018-06-01

Full Text Available Histamine is a critical mediator of IgE/mast cell-mediated anaphylaxis, a neurotransmitter and a regulator of gastric acid secretion. Histamine is a monoamine synthesized from the amino acid histidine through a reaction catalyzed by the enzyme histidine decarboxylase (HDC, which removes carboxyl group from histidine. Despite the importance of histamine, transcriptional regulation of HDC gene expression in mammals is still poorly understood. In this review, we focus on discussing advances in the understanding of molecular regulation of mammalian histamine synthesis.

Synthesis and characterization of carboxymethyl potato starch and its application in reactive dye printing.

Science.gov (United States)

Zhang, Bing; Gong, Honghong; Lü, Shaoyu; Ni, Boli; Liu, Mingzhu; Gao, Chunmei; Huang, Yinjuan; Han, Fei

2012-11-01

Carboxymethyl potato starch (CMPS) was synthesized with a simple dry and multi-step method as a product of the reaction of native potato starch and monochloroacetic acid in the presence of sodium hydroxide. The influence of the molar ratio of sodium hydroxide to anhydroglucose unit, the volume of 95% (v/v) ethanol, the rotation rate of motor driven stirrer and the reaction time for degree of substitution (DS) were evaluated. The product was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffractometry (XRD). FTIR spectrometry showed new bonds at 1618 and 1424 cm⁻¹ when native starch underwent carboxymethylation. SEM pictures showed that the smooth surface of native starch particles was mostly ruptured. XRD revealed that starch crystallinity was reduced after carboxymethylation. The viscosity of the mixture paste of carboxymethyl starch and sodium alginate (SA) was measured using a rotational viscometer. In addition, the applied effect of mixed paste in reactive dye printing was examined by assessing the fabric stiffness, color yield and sharp edge to the printed image in comparison with SA. And the results indicated that the mixed paste could partially replace SA as thickener in reactive dye printing. The study also showed that the method was low cost and eco-friendly and the product would have an extensive application in reactive dye printing. Copyright © 2012 Elsevier B.V. All rights reserved.

Enzymatic transformation of nonfood biomass to starch

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You, Chun; Chen, Hongge; Myung, Suwan; Sathitsuksanoh, Noppadon; Ma, Hui; Zhang, Xiao-Zhou; Li, Jianyong; Zhang, Y.-H. Percival

2013-01-01

The global demand for food could double in another 40 y owing to growth in the population and food consumption per capita. To meet the world’s future food and sustainability needs for biofuels and renewable materials, the production of starch-rich cereals and cellulose-rich bioenergy plants must grow substantially while minimizing agriculture’s environmental footprint and conserving biodiversity. Here we demonstrate one-pot enzymatic conversion of pretreated biomass to starch through a nonnatural synthetic enzymatic pathway composed of endoglucanase, cellobiohydrolyase, cellobiose phosphorylase, and alpha-glucan phosphorylase originating from bacterial, fungal, and plant sources. A special polypeptide cap in potato alpha-glucan phosphorylase was essential to push a partially hydrolyzed intermediate of cellulose forward to the synthesis of amylose. Up to 30% of the anhydroglucose units in cellulose were converted to starch; the remaining cellulose was hydrolyzed to glucose suitable for ethanol production by yeast in the same bioreactor. Next-generation biorefineries based on simultaneous enzymatic biotransformation and microbial fermentation could address the food, biofuels, and environment trilemma. PMID:23589840

Responses to Starch Infusion on Milk Synthesis in Low Yield Lactating Dairy Cows

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Yang Zou

2015-09-01

Full Text Available The effect of starch infusion on production, metabolic parameters and relative mRNA abundance was investigated in low yield lactating cows from 86 days in milk. Six Holstein cows fitted with permanent ruminal cannulas were arranged into one of two complete 3×3 Latin squares and infused with a starch solution containing 800 grams starch for 16 days. The three treatments were: i ruminal and abomasal infusion with water (Control; ii ruminal infusion with cornstarch solution and abomasal infusion with water (Rumen; iii ruminal infusion with water and abomasal infusion with cornstarch solution (Abomasum. There were no significant differences (p>0.05 among the three treatments with low yield lactating cows in feed and energy intake, milk yield and composition, plasma metabolism, or even on gene expression. However, cows receiving starch through rumen performed better than directly through the abomasum during the glucose tolerance test procedure with a higher area under the curve (AUC; p = 0.08 and shorter half-time (t1/2; p = 0.11 of plasma insulin, therefore, it increased glucose disposal, which stated a lipid anabolism other than mobilization after energy supplementation. In conclusion, extra starch infusion at concentration of 800 g/d did not enhance energy supplies to the mammary gland and improve the lactating performance in low yield lactating cows.

Facile Synthesis of Curcumin-Loaded Starch-Maleate Nanoparticles

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Suh Cem Pang

2014-01-01

Full Text Available We have demonstrated the loading of curcumin onto starch maleate (SM under mild conditions by mixing dissolved curcumin and SM nanoparticles separately in absolute ethanol and ethanol/aqueous (40 : 60 v/v, respectively. Curcumin-loaded starch-maleate (CurSM nanoparticles were subsequently precipitated from a homogeneous mixture of these solutions in absolute ethanol based on the solvent exchange method. TEM analysis indicated that the diameters of CurSM nanoparticles were ranged between 30 nm and 110 nm with a mean diameter of 50 nm. The curcumin loading capacity of SM as a function of loading duration was investigated using the UV-visible spectrophotometer. The loading of curcumin onto SM increased rapidly initially with loading duration, and the curcumin loading capacity of 15 mg/g was reached within 12 hours. CurSM nanoparticles exhibited substantially higher water solubility of 6.0 × 10−2 mg/mL which is about 300 times higher than that of pure curcumin. With enhanced water solubility and bioaccessibility of curcumin, the potential utility of CurSM nanoparticles in various biomedical applications is therefore envisaged.

Low frequency ultrasonic-assisted hydrolysis of starch in the presence of α-amylase.

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Gaquere-Parker, Anne; Taylor, Tamera; Hutson, Raihannah; Rizzo, Ashley; Folds, Aubrey; Crittenden, Shastina; Zahoor, Neelam; Hussein, Bilal; Arruda, Aaron

2018-03-01

Hydrolysis of starch is an important process in the food industry and in the production of bioethanol or smaller carbohydrate molecules that can be used as starting blocks for chemical synthesis. Such hydrolysis can be enhanced by lowering the pH, heating the reaction mixture or catalyzing the reaction with enzymes. This study reports the effect of sonication on the reaction rate of starch hydrolysis at different temperatures, in the presence or absence of alpha-amylase. Starch Azure, a commercially available potato starch covalently linked with Remazol Brilliant Blue, has been chosen since its hydrolysis releases a blue dye, which concentration can be monitored by UV Vis spectroscopy. Ultrasounds, regardless of experimental conditions, provide the highest reaction rate for such hydrolysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis and characterization of rice starch laurate as food-grade emulsifier for canola oil-in-water emulsions.

Science.gov (United States)

García-Tejeda, Y V; Leal-Castañeda, E J; Espinosa-Solis, V; Barrera-Figueroa, V

2018-08-15

The effect of esterification on hydrolyzed rice starch was analyzed, for this aim rice starch was hydrolyzed and subsequently esterified with lauroyl chloride at three modification levels. Starch derivatives were characterized regarding their degree of substitution (DS), water solubility index, z-potential, gelatinization, and digestibility properties. DS of derivatives of rice starch laurate ranged from 0.042 to 1.86. It was determined that after esterification the water solubility index increased from 3.44 to 53.61%, the z-potential decreased from -3.18 to -11.27, and the content of slowly digestible starch (SDS) decreased from 26.22 to 5.13%. Different emulsions with starch concentrations ranging from 6 to 30 wt% were evaluated. The most stable emulsions were those having 20 and 30 wt% of rice starch laurate. Copyright © 2018 Elsevier Ltd. All rights reserved.

Identification and phylogenetic analysis of a novel starch synthase in maize

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Hanmei eLiu

2015-11-01

Full Text Available Starch is an important reserve of carbon and energy in plants, providing the majority of calories in the human diet and animal feed. Its synthesis is orchestrated by several key enzymes, and the amount and structure of starch, affecting crop yield and quality, are determined mainly by starch synthase (SS activity. To date, five SS isoforms, including SSI-IV and Granule Bound Starch Synthase (GBSS have been identified and their physiological functions have been well characterized. Here, we report the identification of a new SS isoform in maize, designated SSV. By searching sequenced genomes, SSV has been found in all green plants with conserved sequences and gene structures. Our phylogenetic analysis based on 780 base pairs has suggested that SSIV and SSV resulted from a gene duplication event, which may have occurred before the algae formation. An expression profile analysis of SSV in maize has indicated that ZmSSV is mainly transcribed in the kernel and ear leaf during the grain filling stage, which is partly similar to other SS isoforms. Therefore, it is likely that SSV may play an important role in starch biosynthesis. Subsequent analysis of SSV function may facilitate understanding the mechanism of starch granules formation, number and structure.

Effect of starch isolation method on properties of sweet potato starch

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A. SURENDRA BABU

2014-08-01

Full Text Available Isolation method of starch with different agents influences starch properties, which provide attention for studying the most appropriate method for isolation of starch. In the present study sweet potato starch was isolated by Sodium metabisulphate (M1, Sodium chloride (M2, and Distilled water (M3 methods and these were assessed for functional, chemical, pasting and structural properties. M3 yielded the greatest recovery of starch (10.20%. Isolation methods significantly changed swelling power and pasting properties but starches exhibited similar chemical properties. Sweet potato starches possessed C-type diffraction pattern. Small size granules of 2.90 μm were noticed in SEM of M3 starch. A high degree positive correlation was found between ash, amylose, and total starch content. The study concluded that isolation methods brought changes in yield, pasting and structural properties of sweet potato starch.

Peroxydisulfate initiated synthesis of potato starch-graft-poly(acrylonitrile under microwave irradiation

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2007-01-01

Full Text Available Potato starch-graft-poly(acrylonitrile could be efficiently synthesized using small concentration of ammonium peroxydisulfate (0.0014M in aqueous medium under microwave irradiation. A representative microwave synthesized graft copolymer was characterized using Fourier Transform Infrared Spectroscopy, X-ray Diffraction, Scanning Electron Microscopy and Thermogravimetric Analysis. Under microwave conditions oxygen removal from the reaction vessel was not required and the graft copolymer was obtained in high yield using very small amount of ammonium peroxydisulfate, however using the same amount of ammonium peroxydisulfate (0.0014M on thermostatic water bath no grafting was observed up to 98°C (even in inert atmosphere. Raising the concentration of the initiator to 0.24 M resulted into 10% grafting at 50 °C but in inert atmosphere.The viscosity/shear stability of the grafted starch (aqueous solution and water/saline retention ability of the microwave synthesized graft copolymer were also studied and compared with that of the native potato starch.

Facile Precursor for Synthesis of Silver Nanoparticles Using Alkali Treated Maize Starch

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El-Rafie, M. H.; Ahmed, Hanan B.; Zahran, M. K.

2014-01-01

Silver nanoparticles were prepared by using alkali treated maize starch which plays a dual role as reducer for AgNO3 and stabilizer for the produced AgNPs. The redox reaction which takes a place between AgNO3 and alkali treated starch was followed up and controlled in order to obtain spherical shaped silver nanoparticles with mean size 4–6 nm. The redox potentials confirmed the principle role of alkali treatment in increasing the reducibility of starch macromolecules. The measurements of reducing sugars at the end of reaction using dinitrosalicylic acid reagent (DNS) were carried out in order to control the chemical reduction reaction. The UV/Vis spectra show that an absorption peak, occurring due to surface plasmon resonance (SPR), exists at 410 nm, which is characteristic to yellow color of silver nanoparticles solution. The samples have been characterized by transmission electron microscopy (TEM), which reveal the nanonature of the particles. PMID:27433508

Investigations on structural and optical properties of starch capped ZnS nanoparticles synthesized by microwave irradiation method

Science.gov (United States)

Lalithadevi, B.; Mohan Rao, K.; Ramananda, D.

2018-05-01

Following a green synthesis method, zinc sulfide (ZnS) nanoparticles were prepared by chemical co-precipitation technique using starch as capping agent. Microwave irradiation was used as heating source. X-ray diffraction studies indicated that nanopowders obtained were polycrystalline possessing ZnS simple cubic structure. Transmission electron microscopic studies indicated that starch limits the agglomeration by steric stabilization. Interaction between ZnS and starch was confirmed by Fourier transform infrared spectroscopy as well as Raman scattering studies. Quantum size effects were observed in optical absorption studies while quenching of defect states on nanoparticles was improved with increase in starch addition as indicated by photoluminescence spectra.

Contribution of granule bound starch synthase in kernel modification ...

African Journals Online (AJOL)

The role of gbssI and gbssII genes, encoding granule bound starch synthase enzyme I and II, respectively, in quality protein maize (QPM) were studied at different days after pollination (DAP). Total RNA was used for first strand cDNA synthesis using the ImpromIISriptTM reverse transcriptase. No detectable levels of gbssI ...

Synthesis, characterization and antibacterial activity of biodegradable starch/PVA composite films reinforced with cellulosic fibre.

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Priya, Bhanu; Gupta, Vinod Kumar; Pathania, Deepak; Singha, Amar Singh

2014-08-30

Cellulosic fibres reinforced composite blend films of starch/poly(vinyl alcohol) (PVA) were prepared by using citric acid as plasticizer and glutaraldehyde as the cross-linker. The mechanical properties of cellulosic fibres reinforced composite blend were compared with starch/PVA crossed linked blend films. The increase in the tensile strength, elongation percentage, degree of swelling and biodegradability of blend films was evaluated as compared to starch/PVA crosslinked blend films. The value of different evaluated parameters such as citric acid, glutaraldehyde and reinforced fibre to starch/PVA (5:5) was found to be 25 wt.%, 0.100 wt.% and 20 wt.%, respectively. The blend films were characterized using Fourier transform-infrared spectrophotometry (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA/DTA/DTG). Scanning electron microscopy illustrated a good adhesion between starch/PVA blend and fibres. The blend films were also explored for antimicrobial activities against pathogenic bacteria like Staphylococcus aureus and Escherichia coli. The results confirmed that the blended films may be used as exceptional material for food packaging. Copyright © 2014 Elsevier Ltd. All rights reserved.

VAPOR MIXER FOR GELATINIZATION OF STARCH IN LIQUEFYING STATION

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V. V. Ananskikh

2015-01-01

Full Text Available Starch hydrolysis is main technological process in production of starch sweeteners. Acid hydrolysis of starch using hydrochloric acid is carried out very fast but it does not allow to carry out full hydrolysis and to produce products with given carbohydrate composition. Bioconversion of starch allows to eliminate these limitations. At production of starch sweeteners from starch using enzymes starch hydrolysis is carried out in two stages At first starch – starch liquefaction the rapid increase of viscosity takes place which requires intensive mixing. Liquefying station consists of jet-cooker, holder, pressure regulator and evaporator. Jet-cooker of starch is its main part, starch is quickly turns into soluble (gelatinized state and it is partially liquefied by injection of starch suspension by flow of water vapor under pressure not less than 0,8 MPa. Heat and hydraulic calculation were carried out in order to determine constructive sizes of mixer for cooking of starch. The main hydraulic definable parameters are pressure drop in mixer, vapor pressure at mixer inlet, daily capacity of station by glucose syrup M, product consumption (starch suspension, diameter of inlet section of vapor nozzle. The goal of calculation was to determine vapor consumption M1, diameter d2 of outlet section of confuser injector, length l2 of gelatinization section. For heat calculation there was used Shukhov’s formula along with heat balance equation for gelatinization process. The numerical solution obtained with adopted assumptions given in applied mathematical package MATHCAD, for M = 50 t/day gives required daily vapor consumption M1 = 14,446 т. At hydraulic calculation of pressure drop in mixer there was used Bernoulli’s theorem. Solving obtained equations using MATHCAD found diameter of outlet section of consufer d2 = 0,023 м, vapor pressure inside of mixer p2 = 3,966·105 Па, l2 = 0,128 м. Developed method of calculation is used to determine

Hyperphosphorylation of cereal starch

DEFF Research Database (Denmark)

Carciofi, Massimiliano; Shaik, Shahnoor Sultana; Jensen, Susanne Langgård

2011-01-01

Plant starch is naturally phosphorylated at a fraction of the C6 and the C3 hydroxyl groups during its biosynthesis in plastids. Starch phosphate esters are important in starch metabolism and they also generate specific industrial functionality. Cereal grains starch contains little starch bound...... phosphate compared with potato tuber starch and in order to investigate the effect of increased endosperm starch phosphate, the potato starch phosphorylating enzyme glucan water dikinase (StGWD) was overexpressed specifically in the developing barley endosperm. StGWD overexpressors showed wild......-type phenotype. Transgenic cereal grains synthesized starch with higher starch bound phosphate content (7.5 (±0.67) nmol/mg) compared to control lines (0.8 (±0.05) nmol/mg) with starch granules showing altered morphology and lower melting enthalpy. Our data indicate specific action of GWD during starch...

Plastid-to-Nucleus Retrograde Signals Are Essential for the Expression of Nuclear Starch Biosynthesis Genes during Amyloplast Differentiation in Tobacco BY-2 Cultured Cells1[W][OA

Science.gov (United States)

Enami, Kazuhiko; Ozawa, Tomoki; Motohashi, Noriko; Nakamura, Masayuki; Tanaka, Kan; Hanaoka, Mitsumasa

2011-01-01

Amyloplasts, a subtype of plastid, are found in nonphotosynthetic tissues responsible for starch synthesis and storage. When tobacco (Nicotiana tabacum) Bright Yellow-2 cells are cultured in the presence of cytokinin instead of auxin, their plastids differentiate from proplastids to amyloplasts. In this program, it is well known that the expression of nucleus-encoded starch biosynthesis genes, such as ADP-Glucose Pyrophosphorylase (AgpS) and Granule-Bound Starch Synthase (GBSS), is specifically induced. In this study, we investigated the roles of plastid gene expression in amyloplast differentiation. Microarray analysis of plastid genes revealed that no specific transcripts were induced in amyloplasts. Nevertheless, amyloplast development accompanied with starch biosynthesis was drastically inhibited in the presence of plastid transcription/translation inhibitors. Surprisingly, the expression of nuclear AgpS and GBSS was significantly repressed by the addition of these inhibitors, suggesting that a plastid-derived signal(s) that reflects normal plastid gene expression was essential for nuclear gene expression. A series of experiments was performed to examine the effects of intermediates and inhibitors of tetrapyrrole biosynthesis, since some of the intermediates have been characterized as candidates for plastid-to-nucleus retrograde signals. Addition of levulinic acid, an inhibitor of tetrapyrrole biosynthesis, resulted in the up-regulation of nuclear AgpS and GBSS gene expression as well as starch accumulation, while the addition of heme showed opposite effects. Thus, these results indicate that plastid transcription and/or translation are required for normal amyloplast differentiation, regulating the expression of specific nuclear genes by unknown signaling mechanisms that can be partly mediated by tetrapyrrole intermediates. PMID:21771917

Physicochemical properties of starches isolated from pumpkin compared with potato and corn starches.

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Przetaczek-Rożnowska, Izabela

2017-08-01

The aim of the study was to characterize the selected physicochemical, thermal and rheological properties of pumpkin starches and compared with the properties of potato and corn starches used as control samples. Pumpkin starches could be used in the food industry as a free gluten starch. Better thermal and rheological properties could contribute to reduce the costs of food production. The syneresis of pumpkin starches was similar to that of potato starch but much lower than that for corn starch. Pasting temperatures of pumpkin starches were lower by 17-21.7°C and their final viscosities were over 1000cP higher than corn paste, but were close to the values obtained for potato starch. The thermodynamic characteristic showed that the transformation temperatures of pumpkin starches were lower than those measured for control starches. A level of retrogradation was much lower in pumpkin starch pastes (32-48%) than was in the case of corn (59%) or potato (77%) starches. The pumpkin starches gels were characterized by a much greater hardness, cohesiveness and chewiness, than potato or corn starches gels. Copyright © 2017 Elsevier B.V. All rights reserved.

Microwave synthesis and adsorption performance of a novel crosslinked starch microsphere

Energy Technology Data Exchange (ETDEWEB)

Lin, Qintie, E-mail: qintlin@163.com [School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006 (China); National Engineering Laboratory for Rice and By-Product Deep Processing, Center South University of Forestry and Technology, Changsha 41004 (China); Pan, Jianxin [School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Lin, Qinlu [National Engineering Laboratory for Rice and By-Product Deep Processing, Center South University of Forestry and Technology, Changsha 41004 (China); Liu, Qianjun [School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006 (China)

2013-12-15

Highlights: • CSM was synthesized in a microwave-assisted inversed emulsion system. • The adsorption of methyl violet on CSM was exothermic and spontaneous. • The adsorption process followed the pseudo-second-order kinetics. • The isothermal data obeyed the Langmuir model. • pH variations did not significantly affect the adsorption of methyl violet onto CSM. -- Abstract: A new crosslinked starch microsphere (CSM) was synthesized in a microwave-assisted inversed emulsion system with soluble starch (ST) as a raw material, MBAA as a crosslinker, and K{sub 2}S{sub 2}O{sub 8}–NaHSO{sub 3} as an initiator. The synthesized starch microsphere was characterized and examined by scanning electron microscope (SEM), FTIR spectroscopy and adsorption isotherms of N{sub 2} at 77 K. Adsorption performance was investigated in methyl violet solution. The results showed that the maximum adsorption capacity for MV was 99.3 mg/g at 298 K, and the adsorption fitted pseudo-second-order kinetic model well with correlation coefficients greater than 0.99. The isothermal data obeyed the Langmuir model better compared to Freundlich model and Tempkin model, and the adsorption was exothermic and spontaneous. pH variations (2.0–10.0) did not significantly affect the adsorption of MV onto CSM.

Leaf Starch Turnover Occurs in Long Days and in Falling Light at the End of the Day.

Science.gov (United States)

Fernandez, Olivier; Ishihara, Hirofumi; George, Gavin M; Mengin, Virginie; Flis, Anna; Sumner, Dean; Arrivault, Stéphanie; Feil, Regina; Lunn, John E; Zeeman, Samuel C; Smith, Alison M; Stitt, Mark

2017-08-01

We investigated whether starch degradation occurs at the same time as starch synthesis in Arabidopsis ( Arabidopsis thaliana ) leaves in the light. Starch accumulated in a linear fashion for about 12 h after dawn, then accumulation slowed and content plateaued. Following decreases in light intensity, the rate of accumulation of starch declined in proportion to the decline in photosynthesis if the decrease occurred 14 h after dawn and in response to decreases in light intensity that occurred >10 h after dawn. Starch measurements in circadian clock mutants suggested that the clock influences the timing of onset of degradation. We conclude that the propensity for leaf starch to be degraded increases with time after dawn. The importance of this phenomenon for efficient use of carbon for growth in long days and for prevention of starvation during twilight is discussed. © 2017 American Society of Plant Biologists. All Rights Reserved.

Starch phosphorylation plays an important role in starch biosynthesis

NARCIS (Netherlands)

Xu, Xuan; Dees, Dianka; Dechesne, Annemarie; Huang, Xing Feng; Visser, Richard G.F.; Trindade, Luisa M.

2017-01-01

Starch phosphate esters are crucial in starch metabolism and render valuable functionality to starches for various industrial applications. A potato glucan, water dikinase (GWD1) was introduced in tubers of two different potato genetic backgrounds: an amylose-containing line Kardal and the

Reduction of the plastidial phosphorylase in potato (Solanum tuberosum L.) reveals impact on storage starch structure during growth at low temperature.

Science.gov (United States)

Orawetz, Tom; Malinova, Irina; Orzechowski, Slawomir; Fettke, Joerg

2016-03-01

Tubers of potato (Solanum tuberosum L.), one of the most important crops, are a prominent example for an efficient production of storage starch. Nevertheless, the synthesis of this storage starch is not completely understood. The plastidial phosphorylase (Pho1; EC 2.4.1.1) catalyzes the reversible transfer of glucosyl residues from glucose-1-phosphate to the non-reducing end of α-glucans with the release of orthophosphate. Thus, the enzyme is in principle able to act during starch synthesis. However, so far under normal growth conditions no alterations in tuber starch metabolism were observed. Based on analyses of other species and also from in vitro experiments with potato tuber slices it was supposed, that Pho1 has a stronger impact on starch metabolism, when plants grow under low temperature conditions. Therefore, we analyzed the starch content, granule size, as well as the internal structure of starch granules isolated from potato plants grown under low temperatures. Besides wild type, transgenic potato plants with a strong reduction in the Pho1 activity were analyzed. No significant alterations in starch content and granule size were detected. In contrast, when plants were cultivated at low temperatures the chain length distributions of the starch granules were altered. Thus, the granules contained more short glucan chains. That was not observed in the transgenic plants, revealing that Pho1 in wild type is involved in the formation of the short glucan chains, at least at low temperatures. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Aroma interactions with starch

DEFF Research Database (Denmark)

Jørgensen, Anders Dysted

Starches are used to enhance aroma perception in low-fat foods. Aroma compounds can bind physically to the starch in grooves on the surface or they can form complexes inside amylose helices. This study has been divided into two parts: one part regarding binding of aromas to starches and their aroma......-release, and another part regarding stimulation of a fungal secretome using different carbohydrates. In the first part, nine aromas and one aroma-mixture were mixed with nine different starches, including genetically modified starches. The objective of this sub-project was to bind aromas to the starches to 15 weight......-percent. Aroma binding was tested on both amorphous starches and on native starch granules. A series of aldehydes and alcohols were also tested for binding to the starches. The aromas with the highest volatility were positively retained by starch, whereas for aromas with a lower volatility the starch had...

Preparation of starch nanoparticles in water in oil microemulsion system and their drug delivery properties.

Science.gov (United States)

Wang, Xinge; Chen, Haiming; Luo, Zhigang; Fu, Xiong

2016-03-15

In this research, 1-hexadecyl-3-methylimidazolium bromide C16mimBr/butan-1-ol/cyclohexane/water ionic liquid microemulsion was prepared. The effects of n-alkyl alcohols, alkanes, water content and temperature on the properties of microemulsion were studied by dilution experiment. The microregion of microemulsion was identified by pseudo-ternary phase diagram and conductivity measurement. Then starch nanoparticles were prepared by water in oil (W/O) microemulsion-cross-linking methods with C16mimBr as surfactant. Starch nanoparticles with a mean diameter of 94.3nm and narrow size distribution (SD=3.3) were confirmed by dynamic light scattering (DLS). Scanning electron microscope (SEM) data revealed that starch nanoparticles were spherical granules with the size about 60nm. Moreover the results of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) demonstrated the formation of cross-linking bonds in starch molecules. Finally, the drug loading and releasing properties of starch nanoparticles were investigated with methylene blue (MB) as drug model. This work may provide an efficient pathway to synthesis starch nanoparticles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enzymatic degradation behavior and cytocompatibility of silk fibroin-starch-chitosan conjugate membranes

Energy Technology Data Exchange (ETDEWEB)

Baran, Erkan T., E-mail: erkantur@metu.edu.tr; Tuzlakoglu, Kadriye, E-mail: kadriye@dep.uminho.pt; Mano, Joao F., E-mail: jmano@dep.uminho.pt; Reis, Rui L., E-mail: rgreis@dep.uminho.pt

2012-08-01

The objective of this study was to investigate the influence of silk fibroin and oxidized starch conjugation on the enzymatic degradation behavior and the cytocompatability of chitosan based biomaterials. The tensile stress of conjugate membranes, which was at 50 Megapascal (MPa) for the lowest fibroin and starch composition (10 weight percent (wt.%)), was decreased significantly with the increased content of fibroin and starch. The weight loss of conjugates in {alpha}-amylase was more notable when the starch concentration was the highest at 30 wt.%. The conjugates were resistant to the degradation by protease and lysozyme except for the conjugates with the lowest starch concentration. After 10 days of cell culture, the proliferation of osteoblast-like cells (SaOS-2) was stimulated significantly by higher fibroin compositions and the DNA synthesis on the conjugate with the highest fibroin (30 wt.%) was about two times more compared to the native chitosan. The light microscopy and the image analysis results showed that the cell area and the lengths were decreased significantly with higher fibroin/chitosan ratio. The study proved that the conjugation of fibroin and starch with the chitosan based biomaterials by the use of non-toxic reductive alkylation crosslinking significantly improved the cytocompatibility and modulated the biodegradation, respectively. - Highlights: Black-Right-Pointing-Pointer Silk fibroin, starch and chitosan conjugates were prepared by reductive alkylation. Black-Right-Pointing-Pointer The enzymatic biodegradation and the cytocompatibility of conjugates were tested. Black-Right-Pointing-Pointer The conjugate with 30% starch composition was degraded by {alpha}-amylase significantly. Black-Right-Pointing-Pointer Higher starch composition in conjugates prevented protease and lysozyme degradation. Black-Right-Pointing-Pointer Fibroin incorporation effectively increased the cell proliferation of conjugates.

Mechanical, barrier and morphological properties of starch nanocrystals-reinforced pea starch films.

Science.gov (United States)

Li, Xiaojing; Qiu, Chao; Ji, Na; Sun, Cuixia; Xiong, Liu; Sun, Qingjie

2015-05-05

To characterize the pea starch films reinforced with waxy maize starch nanocrystals, the mechanical, water vapor barrier and morphological properties of the composite films were investigated. The addition of starch nanocrystals increased the tensile strength of the composite films, and the value of tensile strength of the composite films was highest when starch nanocrystals content was 5% (w/w). The moisture content (%), water vapor permeability, and water-vapor transmission rate of the composite films significantly decreased as starch nanocrystals content increased. When their starch nanocrystals content was 1-5%, the starch nanocrystals dispersed homogeneously in the composite films, resulting in a relatively smooth and compact film surface and better thermal stability. However, when starch nanocrystals content was more than 7%, the starch nanocrystals began to aggregate, which resulted in the surface of the composite films developing a longitudinal fibrous structure. Copyright © 2014 Elsevier Ltd. All rights reserved.

Barley grain constituents, starch composition, and structure affect starch in vitro enzymatic hydrolysis.

Science.gov (United States)

Asare, Eric K; Jaiswal, Sarita; Maley, Jason; Båga, Monica; Sammynaiken, Ramaswami; Rossnagel, Brian G; Chibbar, Ravindra N

2011-05-11

The relationship between starch physical properties and enzymatic hydrolysis was determined using ten different hulless barley genotypes with variable carbohydrate composition. The ten barley genotypes included one normal starch (CDC McGwire), three increased amylose starches (SH99250, SH99073, and SB94893), and six waxy starches (CDC Alamo, CDC Fibar, CDC Candle, Waxy Betzes, CDC Rattan, and SB94912). Total starch concentration positively influenced thousand grain weight (TGW) (r(2) = 0.70, p starch concentration (r(2) = -0.80, p hydrolysis of pure starch (r(2) = -0.67, p starch concentration (r(2) = 0.46, p starch (RS) in meal and pure starch samples. The rate of starch hydrolysis was high in pure starch samples as compared to meal samples. Enzymatic hydrolysis rate both in meal and pure starch samples followed the order waxy > normal > increased amylose. Rapidly digestible starch (RDS) increased with a decrease in amylose concentration. Atomic force microscopy (AFM) analysis revealed a higher polydispersity index of amylose in CDC McGwire and increased amylose genotypes which could contribute to their reduced enzymatic hydrolysis, compared to waxy starch genotypes. Increased β-glucan and dietary fiber concentration also reduced the enzymatic hydrolysis of meal samples. An average linkage cluster analysis dendrogram revealed that variation in amylose concentration significantly (p starch concentration in meal and pure starch samples. RS is also associated with B-type granules (5-15 μm) and the amylopectin F-III (19-36 DP) fraction. In conclusion, the results suggest that barley genotype SH99250 with less decrease in grain weight in comparison to that of other increased amylose genotypes (SH99073 and SH94893) could be a promising genotype to develop cultivars with increased amylose grain starch without compromising grain weight and yield.

Inducing PLA/starch compatibility through butyl-etherification of waxy and high amylose starch.

Science.gov (United States)

Wokadala, Obiro Cuthbert; Emmambux, Naushad Mohammad; Ray, Suprakas Sinha

2014-11-04

In this study, waxy and high amylose starches were modified through butyl-etherification to facilitate compatibility with polylactide (PLA). Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and wettability tests showed that hydrophobic butyl-etherified waxy and high amylose starches were obtained with degree of substitution values of 2.0 and 2.1, respectively. Differential scanning calorimetry, tensile testing, and scanning electron microscopy (SEM) demonstrated improved PLA/starch compatibility for both waxy and high amylose starch after butyl-etherification. The PLA/butyl-etherified waxy and high amylose starch composite films had higher tensile strength and elongation at break compared to PLA/non-butyl-etherified composite films. The morphological study using SEM showed that PLA/butyl-etherified waxy starch composites had a more homogenous microstructure compared to PLA/butyl-etherified high amylose starch composites. Thermogravimetric analysis showed that PLA/starch composite thermal stability decreased with starch butyl-etherification for both waxy and high amylose starches. This study mainly demonstrates that PLA/starch compatibility can be improved through starch butyl-etherification. Copyright © 2014 Elsevier Ltd. All rights reserved.

Substituent distribution within cross-linked and hydroxypropylated sweet potato starch and potato starch

NARCIS (Netherlands)

Zhao, J.; Schols, H.A.; Chen Zenghong,; Jin Zhengyu,; Buwalda, P.L.; Gruppen, H.

2012-01-01

Revealing the substituents distribution within starch can help to understand the changes of starch properties after modification. The distribution of substituents over cross-linked and hydroxypropylated sweet potato starch was investigated and compared with modified potato starch. The starches were

Acute myotube protein synthesis regulation by IL-6-related cytokines.

Science.gov (United States)

Gao, Song; Durstine, J Larry; Koh, Ho-Jin; Carver, Wayne E; Frizzell, Norma; Carson, James A

2017-11-01

IL-6 and leukemia inhibitory factor (LIF), members of the IL-6 family of cytokines, play recognized paradoxical roles in skeletal muscle mass regulation, being associated with both growth and atrophy. Overload or muscle contractions can induce a transient increase in muscle IL-6 and LIF expression, which has a regulatory role in muscle hypertrophy. However, the cellular mechanisms involved in this regulation have not been completely identified. The induction of mammalian target of rapamycin complex 1 (mTORC1)-dependent myofiber protein synthesis is an established regulator of muscle hypertrophy, but the involvement of the IL-6 family of cytokines in this process is poorly understood. Therefore, we investigated the acute effects of IL-6 and LIF administration on mTORC1 signaling and protein synthesis in C2C12 myotubes. The role of glycoprotein 130 (gp130) receptor and downstream signaling pathways, including phosphoinositide 3-kinase (PI3K)-Akt-mTORC1 and signal transducer and activator of transcription 3 (STAT3)-suppressor of cytokine signaling 3 (SOCS3), was investigated by administration of specific siRNA or pharmaceutical inhibitors. Acute administration of IL-6 and LIF induced protein synthesis, which was accompanied by STAT3 activation, Akt-mTORC1 activation, and increased SOCS3 expression. This induction of protein synthesis was blocked by both gp130 siRNA knockdown and Akt inhibition. Interestingly, STAT3 inhibition or Akt downstream mTORC1 signaling inhibition did not fully block the IL-6 or LIF induction of protein synthesis. SOCS3 siRNA knockdown increased basal protein synthesis and extended the duration of the protein synthesis induction by IL-6 and LIF. These results demonstrate that either IL-6 or LIF can activate gp130-Akt signaling axis, which induces protein synthesis via mTORC1-independent mechanisms in cultured myotubes. However, IL-6- or LIF-induced SOCS3 negatively regulates the activation of myotube protein synthesis. Copyright © 2017 the

Preparation And Physicochemical Properties of Octenyl Succinic Anhydride (OSA) Modified Sago Starch

International Nuclear Information System (INIS)

Nur Farhana Zainal Abiddin; Anida Yusoff; Noorlaila Ahmad

2016-01-01

Starch from sago (Metroxylon sagu) was esterified with octenyl succinic anhydride (OSA) in order to regulate its shortcoming by adding amphiphilic properties. The objective of this work is to determine the physicochemical properties of native sago and OSA sago starches. The OSA sago starch was produced according to the optimum condition generated via response surface methodology (RSM) with 5.00 % OSA at pH 7.20 and a reaction time of 9.65 hours. The esterified sago starch gives a degree of substitution (DS) value of 0.012. The physicochemical properties of OSA sago starch was determined by measuring the amylose content, laser diffraction particle size analyzer, scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR). The amylose content for OSA sago starch was found to be reduced after esterification reaction. The particle size of OSA sago starch was found to increase significantly (p<0.05) compared to their native starches. Scanning electron microscopy (SEM) revealed that OSA starch developed slightly rough surface and their edges lost some definition. FT-IR spectroscopy shows that there was appearance of new absorption correspond to ester carbonyl group (1717 cm -1 ) and carboxylate RCOO- (1569 cm -1 ). This study showed that the physicochemical properties of modified starches were influenced not only by DS but also on the botanical origin of the starches. (author)

Thermoplastic starch materials prepared from rice starch

International Nuclear Information System (INIS)

Pontes, Barbara R.B.; Curvelo, Antonio A.S.

2009-01-01

Rice starch is a source still little studied for the preparation of thermoplastic materials. However, its characteristics, such as the presence of proteins, fats and fibers may turn into thermoplastics with a better performance. The present study intends the evaluation of the viability of making starch thermoplastic from rice starch and glycerol as plasticizer. The results of X-ray diffraction and scanning electronic microscopy demonstrate the thermoplastic acquisition. The increase of plasticizer content brings on more hydrophilic thermoplastics with less resistance to tension and elongation at break. (author)

Design starch: stochastic modeling of starch granule biogenesis.

Science.gov (United States)

Raguin, Adélaïde; Ebenhöh, Oliver

2017-08-15

Starch is the most widespread and abundant storage carbohydrate in plants and the main source of carbohydrate in the human diet. Owing to its remarkable properties and commercial applications, starch is still of growing interest. Its unique granular structure made of intercalated layers of amylopectin and amylose has been unraveled thanks to recent progress in microscopic imaging, but the origin of such periodicity is still under debate. Both amylose and amylopectin are made of linear chains of α-1,4-bound glucose residues, with branch points formed by α-1,6 linkages. The net difference in the distribution of chain lengths and the branching pattern of amylose (mainly linear), compared with amylopectin (racemose structure), leads to different physico-chemical properties. Amylose is an amorphous and soluble polysaccharide, whereas amylopectin is insoluble and exhibits a highly organized structure of densely packed double helices formed between neighboring linear chains. Contrarily to starch degradation that has been investigated since the early 20th century, starch production is still poorly understood. Most enzymes involved in starch growth (elongation, branching, debranching, and partial hydrolysis) are now identified. However, their specific action, their interplay (cooperative or competitive), and their kinetic properties are still largely unknown. After reviewing recent results on starch structure and starch growth and degradation enzymatic activity, we discuss recent results and current challenges for growing polysaccharides on granular surface. Finally, we highlight the importance of novel stochastic models to support the analysis of recent and complex experimental results, and to address how macroscopic properties emerge from enzymatic activity and structural rearrangements. © 2017 The Author(s).

Design starch: stochastic modeling of starch granule biogenesis

Science.gov (United States)

Ebenhöh, Oliver

2017-01-01

Starch is the most widespread and abundant storage carbohydrate in plants and the main source of carbohydrate in the human diet. Owing to its remarkable properties and commercial applications, starch is still of growing interest. Its unique granular structure made of intercalated layers of amylopectin and amylose has been unraveled thanks to recent progress in microscopic imaging, but the origin of such periodicity is still under debate. Both amylose and amylopectin are made of linear chains of α-1,4-bound glucose residues, with branch points formed by α-1,6 linkages. The net difference in the distribution of chain lengths and the branching pattern of amylose (mainly linear), compared with amylopectin (racemose structure), leads to different physico-chemical properties. Amylose is an amorphous and soluble polysaccharide, whereas amylopectin is insoluble and exhibits a highly organized structure of densely packed double helices formed between neighboring linear chains. Contrarily to starch degradation that has been investigated since the early 20th century, starch production is still poorly understood. Most enzymes involved in starch growth (elongation, branching, debranching, and partial hydrolysis) are now identified. However, their specific action, their interplay (cooperative or competitive), and their kinetic properties are still largely unknown. After reviewing recent results on starch structure and starch growth and degradation enzymatic activity, we discuss recent results and current challenges for growing polysaccharides on granular surface. Finally, we highlight the importance of novel stochastic models to support the analysis of recent and complex experimental results, and to address how macroscopic properties emerge from enzymatic activity and structural rearrangements. PMID:28673938

Enhanced mechanical, thermal and antimicrobial properties of poly(vinyl alcohol)/graphene oxide/starch/silver nanocomposites films.

Science.gov (United States)

Usman, Adil; Hussain, Zakir; Riaz, Asim; Khan, Ahmad Nawaz

2016-11-20

In the present work, synthesis of poly(vinyl alcohol)/graphene oxide/starch/silver (PVA/GO/Starch/Ag) nanocomposites films is reported. Such films have been characterized and investigated for their mechanical, thermal and antimicrobial properties. The exfoliation of GO in the PVA matrix occurs owing to the non-covalent interactions of the polymer chains of PVA and hydrophilic surface of the GO layers. Presence of GO in PVA and PVA/starch blends were found to enhance the tensile strength of the nanocomposites system. It was found that the thermal stability of PVA as well as PVA/starch blend systems increased by the incorporation of GO where strong physical bonding between GO layers and PVA/starch blends is assumed to cause thermal barrier effects. Antimicrobial properties of the prepared films were investigated against Escherichia coli and Staphylococcus aureus. Our results show enhanced antimicrobial properties of the prepared films where PVA-GO, PVA-Ag, PVA-GO-Ag and PVA-GO-Ag-Starch showed antimicrobial activity in ascending order. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tunable d-Limonene Permeability in Starch-Based Nanocomposite Films Reinforced by Cellulose Nanocrystals.

Science.gov (United States)

Liu, Siyuan; Li, Xiaoxi; Chen, Ling; Li, Lin; Li, Bing; Zhu, Jie

2018-01-31

In order to control d-limonene permeability, cellulose nanocrystals (CNC) were used to regulate starch-based film multiscale structures. The effect of sphere-like cellulose nanocrystal (CS) and rod-like cellulose nanocrystal (CR) on starch molecular interaction, short-range molecular conformation, crystalline structure, and micro-ordered aggregated region structure were systematically discussed. CNC aspect ratio and content were proved to be independent variables to control d-limonene permeability via film-structure regulation. New hydrogen bonding formation and increased hydroxypropyl starch (HPS) relative crystallinity could be the reason for the lower d-limonene permeability compared with tortuous path model approximation. More hydrogen bonding formation, higher HPS relative crystallinity and larger size of micro-ordered aggregated region in CS0.5 and CR2 could explain the lower d-limonene permeability than CS2 and CR0.5, respectively. This study provided new insight for the control of the flavor release from starch-based films, which favored its application in biodegradable food packaging and flavor encapsulation.

Evidence that cellulolysis by an anaerobic ruminal fungus is catabolite regulated by glucose, cellobiose, and soluble starch

International Nuclear Information System (INIS)

Morrison, M.; Mackie, R.I.; Kistner, A.

1990-01-01

A Piromyces-like ruminal fungus was used to study preferential carbohydrate utilization of [U- 14 C]cellulose, both alone and in combination with several soluble sugars. For cells grown on cellulose alone, cellulolytic activity was immediate and, initially, greater than that observed in the presence of added carbohydrate. Cellulolytic activity remained minimal in cultures containing cellulose plus glucose or cellobiose until the soluble sugar was depleted. Soluble starch also regulated cellulose activity but to a lesser extent. The results presented suggest that some fungal cellulases are susceptible to catabolite regulatory mechanisms

Lipase-catalysed acylation of starch and determination of the degree of substitution by methanolysis and GC

Science.gov (United States)

2010-01-01

Background Natural polysaccharides such as starch are becoming increasingly interesting as renewable starting materials for the synthesis of biodegradable polymers using chemical or enzymatic methods. Given the complexity of polysaccharides, the analysis of reaction products is challenging. Results Esterification of starch with fatty acids has traditionally been monitored by saponification and back-titration, but in our experience this method is unreliable. Here we report a novel GC-based method for the fast and reliable quantitative determination of esterification. The method was used to monitor the enzymatic esterification of different starches with decanoic acid, using lipase from Thermomyces lanuginosus. The reaction showed a pronounced optimal water content of 1.25 mL per g starch, where a degree of substitution (DS) of 0.018 was obtained. Incomplete gelatinization probably accounts for lower conversion with less water. Conclusions Lipase-catalysed esterification of starch is feasible in aqueous gel systems, but attention to analytical methods is important to obtain correct DS values. PMID:21114817

Lipase-catalysed acylation of starch and determination of the degree of substitution by methanolysis and GC

Directory of Open Access Journals (Sweden)

Hauer Bernhard

2010-11-01

Full Text Available Abstract Background Natural polysaccharides such as starch are becoming increasingly interesting as renewable starting materials for the synthesis of biodegradable polymers using chemical or enzymatic methods. Given the complexity of polysaccharides, the analysis of reaction products is challenging. Results Esterification of starch with fatty acids has traditionally been monitored by saponification and back-titration, but in our experience this method is unreliable. Here we report a novel GC-based method for the fast and reliable quantitative determination of esterification. The method was used to monitor the enzymatic esterification of different starches with decanoic acid, using lipase from Thermomyces lanuginosus. The reaction showed a pronounced optimal water content of 1.25 mL per g starch, where a degree of substitution (DS of 0.018 was obtained. Incomplete gelatinization probably accounts for lower conversion with less water. Conclusions Lipase-catalysed esterification of starch is feasible in aqueous gel systems, but attention to analytical methods is important to obtain correct DS values.

Oil accumulation in the model green alga Chlamydomonas reinhardtii: characterization, variability between common laboratory strains and relationship with starch reserves

Directory of Open Access Journals (Sweden)

Carrier Patrick

2011-01-01

Full Text Available Abstract Background When cultivated under stress conditions, many microalgae species accumulate both starch and oil (triacylglycerols. The model green microalga Chlamydomonas reinhardtii has recently emerged as a model to test genetic engineering or cultivation strategies aiming at increasing lipid yields for biodiesel production. Blocking starch synthesis has been suggested as a way to boost oil accumulation. Here, we characterize the triacylglycerol (TAG accumulation process in Chlamydomonas and quantify TAGs in various wild-type and starchless strains. Results In response to nitrogen deficiency, Chlamydomonas reinhardtii produced TAGs enriched in palmitic, oleic and linoleic acids that accumulated in oil-bodies. Oil synthesis was maximal between 2 and 3 days following nitrogen depletion and reached a plateau around day 5. In the first 48 hours of oil deposition, a ~80% reduction in the major plastidial membrane lipids occurred. Upon nitrogen re-supply, mobilization of TAGs started after starch degradation but was completed within 24 hours. Comparison of oil content in five common laboratory strains (CC124, CC125, cw15, CC1690 and 11-32A revealed a high variability, from 2 μg TAG per million cell in CC124 to 11 μg in 11-32A. Quantification of TAGs on a cell basis in three mutants affected in starch synthesis (cw15sta1-2, cw15sta6 and cw15sta7-1 showed that blocking starch synthesis did not result in TAG over-accumulation compared to their direct progenitor, the arginine auxotroph strain 330. Moreover, no significant correlation was found between cellular oil and starch levels among the twenty wild-type, mutants and complemented strains tested. By contrast, cellular oil content was found to increase steeply with salt concentration in the growth medium. At 100 mM NaCl, oil level similar to nitrogen depletion conditions could be reached in CC124 strain. Conclusion A reference basis for future genetic studies of oil metabolism in Chlamydomonas

Absorption of wheat starch in patients resected for left-sided colonic cancer

DEFF Research Database (Denmark)

Nordgaard, I; Rumessen, J J; Nielsen, S A

1992-01-01

Bacterial fermentation of carbohydrate in the colon, producing short-chain fatty acids (SCFA)--and especially butyrate--has been shown possibly to impede cell proliferation and regulate cell differentiation of colonocytes. In patients with diverticular disease or benign polyps in the colon...... a hyperabsorption of potato starch in the small intestine has been found. We have investigated the absorption of wheat starch in 15 patients radically resected for cancer in the descending or sigmoid colon, and the results were compared with those of 15 healthy controls. The starch malabsorption was quantified...... also similar in patients and controls. The results do not support the theory that hyperabsorption of starch is characteristic of patients with malignant disease in the large intestine....

Environmental impact assessment of six starch plastics focusing on wastewater-derived starch and additives

NARCIS (Netherlands)

Broeren, Martijn L.M.; Kuling, Lody; Worrell, Ernst; Shen, Li

2017-01-01

Starch plastics are developed for their biobased origin and potential biodegradability. To assist the development of sustainable starch plastics, this paper quantifies the environmental impacts of starch plastics produced from either virgin starch or starch reclaimed from wastewater. A

Removal of heavy elements from Contaminated Matrices using amidoxime chelating starch

International Nuclear Information System (INIS)

Shama, S.A.; Wally, S.A.; Aly, H.F.

2012-01-01

The synthesis of a amidoxime chelating starch was carried out by grafting of acrylonitrile onto starch using the mutual irradiation techniques at dose rate 2.5 kGy. Conversion of nitrile groups of the grafted copolymer into the amidoxime was carried out by treatment with hydroxylamine under alkaline solution. The amidoxime chelating starch was characterized by FT-IR spectra, TG, Particle size, Surface area, SEM, and Elemental analyses. The chelating behavior of the prepared resin was carried out by using uranium. The binding capacity of uranium ion by the amidoxime resin was carried out by the batch technique. The sorption capacity was high for uranium, 86.9 mg/g at ph 6.5. The kinetic exchange rate was fast. It was observed that the uranium uptake ratio reaches 50% at 10 min (t 1/2 ). The treatment process using amidoxime sorbent is efficient to remove uranium from the waste solution of the FMPP plant.

[Starch synthesis in the maize endosperm as affected by starch-synthesizing mutants]. [Annual report, March 1994--June 30, 1995

Energy Technology Data Exchange (ETDEWEB)

Nelson, O.

1995-07-01

Progress is reported in several areas relevant to maize endosperm development. These areas are (1) The tentative identification of the enzymatic deficiency in a previously unknown endosperm mutant, sugary3-1 (su3-1). The evidence leading to this conclusion will be presented below. (2) The recognition that the endosperm mutant that produces an interesting starch resembling some starches that have been chemically modified is actually an unusual, hypomorphic allele (8132) at the brittle2 (bt2) locus; (3) The orange endosperm color present in some progenies derived from a cross between the original bt2-8132 and W22N apparently results from an interaction between two genes, one of which behaves as though linked to the bt2 locus. In the orange endosperm derivative, our limited evidence suggests that the quantity of all the carotinoids present in the yellow endosperm stocks appear to be increased proportionally.

Regulatory effect of amino acids on the pasting behavior of potato starch is attributable to its binding to the starch chain.

Science.gov (United States)

Ito, Azusa; Hattori, Makoto; Yoshida, Tadashi; Watanabe, Ayako; Sato, Ryoichi; Takahashi, Koji

2006-12-27

The binding of an amino acid, glycine (Gly), alanine (Ala), epsilon-aminocaproic acid (-AC), monosodium glutamate (GluNa), or lysine (Lys), to starch was examined by a biomolecular interaction analyzer (IAsys). A starch sample (ATS) hydrolyzed to an extent of 1% hydrolysis rate with 15% sulfuric acid was used as a model starch for the binding examination. The reducing end of ATS was oxidized by the Somogyi reagent, and the conversion of the reducing end to the carboxyl group of ATS was confirmed by a carboxylic acid fluorescence labeling reagent. The oxidized ATS was immobilized to the amino group of a sensor cuvette by using water-soluble carbodiimide and N-hydroxysuccinimide through an amide bond. The IAsys examination showed that Gly, Ala, and epsilon-AC scarcely bound to the immobilized starch chains but that GluNa and Lys favorably bound with their increasing concentrations. The relative binding index (RBI) of each amino acid was defined by the ratio of the slope of the linear regression equation between the binding response and the concentration for each amino acid to that for Gly. Because the relationships between the RBI and the pasting characteristics (pasting temperature, peak viscosity, breakdown, and swelling index) could each be expressed by a linear regression equation with a high correlation coefficient, it is concluded that the regulation of the pasting behavior of starch with an amino acid is caused by binding of the amino acid to the starch chains.

Regulation of cellulose synthesis in response to stress.

Science.gov (United States)

Kesten, Christopher; Menna, Alexandra; Sánchez-Rodríguez, Clara

2017-12-01

The cell wall is a complex polysaccharide network that provides stability and protection to the plant and is one of the first layers of biotic and abiotic stimuli perception. A controlled remodeling of the primary cell wall is essential for the plant to adapt its growth to environmental stresses. Cellulose, the main component of plant cell walls is synthesized by plasma membrane-localized cellulose synthases moving along cortical microtubule tracks. Recent advancements demonstrate a tight regulation of cellulose synthesis at the primary cell wall by phytohormone networks. Stress-induced perturbations at the cell wall that modify cellulose synthesis and microtubule arrangement activate similar phytohormone-based stress response pathways. The integration of stress perception at the primary cell wall and downstream responses are likely to be tightly regulated by phytohormone signaling pathways in the context of cellulose synthesis and microtubule arrangement. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Green synthesis of highly concentrated aqueous colloidal solutions of large starch-stabilised silver nanoplatelets.

Science.gov (United States)

Cheng, Fei; Betts, Jonathan W; Kelly, Stephen M; Hector, Andrew L

2015-01-01

A simple, environmentally friendly and cost-effective method has been developed to prepare a range of aqueous silver colloidal solutions, using ascorbic acid as a reducing agent, water-soluble starch as a combined crystallising, stabilising and solubilising agent, and water as the solvent. The diameter of silver nanoplatelets increases with higher concentrations of AgNO3 and starch. The silver nanoparticles are also more uniform in shape the greater the diameter of the nanoparticles. Colloidal solutions with a very high concentration of large, flat, hexagonal silver nanoplatelets (~230 nm in breadth) have been used to deposit and fix an antibacterial coating of these large starch-stabilised silver nanoplates on commercial cotton fibres, using a simple dip-coating process using water as the solvent, in order to study the dependence of the antibacterial properties of these nanoplatelets on their size. Copyright © 2014 Elsevier B.V. All rights reserved.

The enzymatic determination of starch in food, feed and raw materials of the starch industry

NARCIS (Netherlands)

Brunt, K.; Sanders, P.; Rozema, T.

1998-01-01

An enzymatic starch determination which can be used for the analysis of starch in a very broad range of different samples is evaluated, ranging from starch in plants, feed and food to industrial applications as starch in starch. The method is based on a complete enzymatic conversion of the starch

DISINTEGRATION EFFICIENCY OF SODIUM STARCH GLYCOLATES, PREPARED FROM DIFFERENT NATIVE STARCHES

NARCIS (Netherlands)

BOLHUIS, GK; ARENDSCHOLTE, AW; STUUT, GJ; DEVRIES, JA

1994-01-01

In a comparative evaluation, the disintegration efficiency of sodium starch glycolates prepared from seven different native starches (potato, maize, waxy maize, wheat, rice, sago and tapioca) were compared. All the sodium starch glycolates tested had a high swelling capacity, but the rate of water

Starch behaviors and mechanical properties of starch blend films with different plasticizers.

Science.gov (United States)

Nguyen Vu, Hoang Phuong; Lumdubwong, Namfone

2016-12-10

The main objective of the study was to gain insight into structural and mechanical starch behaviors of the plasticized starch blend films. Mechanical properties and starch behaviors of cassava (CS)/and mungbean (MB) (50/50, w/w) starch blend films containing glycerol (Gly) or sorbitol (Sor) at 33% weight content were investigated. It was found that tensile strength TS and %E of the Gly-CSMB films were similar to those of MB films; but%E of all Sor-films was identical. TS of plasticized films increased when AM content and crystallinity increased. When Sor was substituted for Gly, crystallinity of starch films and their TS increased. The CSMB and MB films had somewhat a similar molecular profile and comparable mechanical properties. Therefore, it was proposed the starch molecular profile containing amylopectin with high M¯w, low M¯w of amylose, and the small size of intermediates may impart the high TS and%E of starch films. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterization of starch films containing starch nanoparticles: part 1: physical and mechanical properties.

Science.gov (United States)

Shi, Ai-Min; Wang, Li-Jun; Li, Dong; Adhikari, Benu

2013-07-25

We report, for the first time, the preparation method and characteristics of starch films incorporating spray dried and vacuum freeze dried starch nanoparticles. Physical properties of these films such as morphology, crystallinity, water vapor permeability (WVP), opacity, and glass transition temperature (Tg) and mechanical properties (strain versus temperature, strain versus stress, Young's modulus and toughness) were measured. Addition of both starch nanoparticles in starch films increased roughness of surface, lowered degree of crystallinity by 23.5%, WVP by 44% and Tg by 4.3°C, respectively compared to those of starch-only films. Drying method used in preparation of starch nanoparticles only affected opacity of films. The incorporation of nanoparticles in starch films resulted into denser films due to which the extent of variation of strain with temperature was much lower. The toughness and Young's modulus of films containing both types of starch nanoparticles were lower than those of control films especially at <100°C. Copyright © 2012 Elsevier Ltd. All rights reserved.

Starch Digestibility and Functional Properties of Rice Starch Subjected to Gamma Radiation

Directory of Open Access Journals (Sweden)

Luís Fernando Polesi

2018-01-01

Full Text Available This study investigated the effect of gamma radiation on the digestibility and functional properties of rice starch. Rice cultivars IRGA417 and IAC202 were used for isolation of starch by the alkaline method. Starch samples were irradiated with 1, 2 and 5 kGy doses of 60Co at a rate of 0.4 kGy/h. A control sample, which was not irradiated, was used for comparison. Irradiated and control starches were characterized by in vitro starch digestibility, total dietary fiber, color, water absorption index, water solubility index, syneresis, swelling factor, amylose leaching, pasting properties and gel firmness. Irradiations changed starch digestibility differently in either cultivar. Increasing radiation doses promoted increase in the color parameter b* (yellow, elevation in the capacity to absorb water, and solubility in water as well as the amylose leached from granules for both cultivars. Pasting properties showed a decrease that was proportional to the dose applied, caused by the depolymerization of starch molecules. Gel firmness of the starch from IAC202 was inversely proportional to the radiation dose applied, whereas for IRGA417, there was a reduction at 5 kGy dose. Rice starches can be modified by irradiation to exhibit different functional characteristics and they can be used by the food industries in products such as soups, desserts, flans, puddings and others.

Copper-mediated homogeneous living radical polymerization of acrylamide with waxy potato starch-based macroinitiator.

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Fan, Yifei; Cao, Huatang; van Mastrigt, Frank; Pei, Yutao; Picchioni, Francesco

2018-07-15

Cu 0 -mediated living radical polymerization (Cu 0 -mediated LRP) was employed in this research for the synthesis of starch-g-polyacrylamide (St-g-PAM). The use of a controlled radical grafting technique is necessary, as compared to the traditional free-radical polymerization methods, in order to obtain a well-defined structure of the final product. This is in turn essential for studying the relationship between such structure and the end-properties. Waxy potato starch-based water-soluble macroinitiator was first synthesized by esterification with 2-bromopropionyl bromide in the mixture of dimethylacetamide and lithium chloride. With the obtained macroinitiator, St-g-PAM was homogeneously synthesized by aqueous Cu 0 -mediated LRP using CuBr/hexamethylated tris(2-aminoethyl)amine (Me 6 Tren) as catalyst. The successful synthesis of the macroinitiator and St-g-PAM was proved by NMR, FT-IR, SEM, XRD and TGA analysis. The molecular weight and polydispersity of PAM chains were analyzed by gel permeation chromatography (GPC) after hydrolyzing the starch backbone. Monomer conversion was monitored by gas chromatography (GC), on the basis of which the kinetics were determined. A preliminarily rheological study was performed on aqueous solutions of the prepared materials. Copyright © 2018 Elsevier Ltd. All rights reserved.

Practical, economical, and eco-friendly starch-supported palladium catalyst for Suzuki coupling reactions.

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Baran, Talat

2017-06-15

In catalytic systems, the support materials need to be both eco friendly and low cost as well as having high thermal and chemical stability. In this paper, a novel starch supported palladium catalyst, which had these outstanding properties, was designed and its catalytic activity was evaluated in a Suzuki coupling reaction under microwave heating with solvent-free and mild reaction conditions. The starch supported catalyst gave remarkable reaction yields after only 5min as a result of the coupling reaction of the phenyl boronic acid with 23 different substrates, which are bearing aril bromide, iodide, and chloride. The longevity of the catalyst was also investigated, and the catalyst could be reused for 10 runs. The starch supported Pd(II) catalyst yielded remarkable TON (up to 25,000) and TOF (up to 312,500) values by using a simple, fast and eco-friendly method. In addition, the catalytic performance of the catalyst was tested against different commercial palladium catalysts, and the green starch supported catalyst had excellent selectivity. The catalytic tests showed that the novel starch based palladium catalyst proved to be an economical and practical catalyst for the synthesis of biaryl compounds. Copyright © 2017 Elsevier Inc. All rights reserved.

Physicochemical properties of starches and proteins in alkali-treated mungbean and cassava starch granules.

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Israkarn, Kamolwan; Na Nakornpanom, Nantarat; Hongsprabhas, Parichat

2014-05-25

This study explored the influences of envelope integrity of cooked starch granules on physicochemical and thermophysical properties of mungbean and cassava starches. Alkali treatment was used to selectively leach amylose from the amorphous region of both starches and partially fragmented starch molecules into lower-molecular-weight polymers. It was found that despite the loss of 40% of the original content of amylose, both mungbean and cassava starches retained similar crystallinities, gelatinization temperature ranges, and pasting profiles compared to the native starches. However, the loss of granule-bound starch synthases during alkali treatment and subsequent alkali cooking in excess water played significant roles in determining granular disintegration. The alterations in envelope integrity due to the negative charge repulsion among polymers within the envelope of swollen granules, and the fragmentation of starch molecules, were responsible for the alterations in thermophysical properties of mungbean and cassava starches cooked under alkaline conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bioplastic from Chitosan and Yellow Pumpkin Starch with Castor Oil as Plasticizer

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Hasan, M.; Rahmayani, R. F. I.; Munandar

2018-03-01

This study has been conducted on bioplastic synthesis of chitosan and yellow pumpkin starch (Cucurbita moschata) with castor oil as plasticizer. The purpose of this study is to determine the characteristics of the effect of chitosan and starch composition of pumpkins against solvent absorption, tensile strength and biodegradable. The first stage of the research is the making of bioplastic by blending yellow pumpkin starch, chitosan and castor oil. Further, it tested the absorption capacity of the solvent, tensile strength test, and biodegradable analysis. The optimum absorption capacity of the solvent is obtained on the composition of Pumpkin/Chitosan was 50/50 in H2O and C2H5OH solvent. Meanwhile the optimum absorbency in HCl and NaOH solvents is obtained by 60/40 composition. The characterization of the optimum tensile strength test was obtained on the 40/60 composition of 6.787 ± 0.274 Mpa and the fastest biodegradation test process within 5-10 days occurred in the 50/50 composition. The more chitosan content the higher the value of tensile strength test obtained, while the fastest biodegradation rate occureds in the composition of yellow pumpkin starch and chitosan balanced 50:50.

Starch meets biotechnology : in planta modification of starch composition and functionalities

NARCIS (Netherlands)

Xu, Xuan

2016-01-01

Storage starch is an energy reservoir for plants and the major source of calories in the human diet. Starch is used in a broad range of industrial applications, as a cheap, abundant, renewable and biodegradable biopolymer. However, starch needs to be modified before it can fulfill the required

Enzymatically Modified Starch Ameliorates Postprandial Serum Triglycerides and Lipid Metabolome in Growing Pigs.

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Metzler-Zebeli, Barbara U; Eberspächer, Eva; Grüll, Dietmar; Kowalczyk, Lidia; Molnar, Timea; Zebeli, Qendrim

2015-01-01

Developing host digestion-resistant starches to promote human health is of great research interest. Chemically modified starches (CMS) are widely used in processed foods and although the modification of the starch molecule allows specific reduction in digestibility, the metabolic effects of CMS have been less well described. This short-term study evaluated the impact of enzymatically modified starch (EMS) on fasting and postprandial profiles of blood glucose, insulin and lipids, and serum metabolome in growing pigs. Eight jugular-vein catheterized pigs (initial body weight, 37.4 kg; 4 months of age) were fed 2 diets containing 72% purified starch (EMS or waxy corn starch (control)) in a cross-over design for 7 days. On day 8, an 8-hour meal tolerance test (MTT) was performed with serial blood samplings. Besides biochemical analysis, serum was analysed for 201 metabolites through targeted mass spectrometry-based metabolomic approaches. Pigs fed the EMS diet showed increased (Pmetabolome profiling identified characteristic changes in glycerophospholipid, lysophospholipids, sphingomyelins and amino acid metabolome profiles with EMS diet compared to control diet. Results showed rapid adaptations of blood metabolites to dietary starch shifts within 7 days. In conclusion, EMS ingestion showed potential to attenuate postprandial raise in serum lipids and suggested constant alteration in the synthesis or breakdown of sphingolipids and phospholipids which might be a health benefit of EMS consumption. Because serum insulin was not lowered, more research is warranted to reveal possible underlying mechanisms behind the observed changes in the profile of serum lipid metabolome in response to EMS consumption.

Feedback Inhibition of Starch Degradation in Arabidopsis Leaves Mediated by Trehalose 6-Phosphate1[W][OPEN

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Martins, Marina Camara Mattos; Hejazi, Mahdi; Fettke, Joerg; Steup, Martin; Feil, Regina; Krause, Ursula; Arrivault, Stéphanie; Vosloh, Daniel; Figueroa, Carlos María; Ivakov, Alexander; Yadav, Umesh Prasad; Piques, Maria; Metzner, Daniela; Stitt, Mark; Lunn, John Edward

2013-01-01

Many plants accumulate substantial starch reserves in their leaves during the day and remobilize them at night to provide carbon and energy for maintenance and growth. In this paper, we explore the role of a sugar-signaling metabolite, trehalose-6-phosphate (Tre6P), in regulating the accumulation and turnover of transitory starch in Arabidopsis (Arabidopsis thaliana) leaves. Ethanol-induced overexpression of trehalose-phosphate synthase during the day increased Tre6P levels up to 11-fold. There was a transient increase in the rate of starch accumulation in the middle of the day, but this was not linked to reductive activation of ADP-glucose pyrophosphorylase. A 2- to 3-fold increase in Tre6P during the night led to significant inhibition of starch degradation. Maltose and maltotriose did not accumulate, suggesting that Tre6P affects an early step in the pathway of starch degradation in the chloroplasts. Starch granules isolated from induced plants had a higher orthophosphate content than granules from noninduced control plants, consistent either with disruption of the phosphorylation-dephosphorylation cycle that is essential for efficient starch breakdown or with inhibition of starch hydrolysis by β-amylase. Nonaqueous fractionation of leaves showed that Tre6P is predominantly located in the cytosol, with estimated in vivo Tre6P concentrations of 4 to 7 µm in the cytosol, 0.2 to 0.5 µm in the chloroplasts, and 0.05 µm in the vacuole. It is proposed that Tre6P is a component in a signaling pathway that mediates the feedback regulation of starch breakdown by sucrose, potentially linking starch turnover to demand for sucrose by growing sink organs at night. PMID:24043444

Comparison of CO(2) and bicarbonate as inorganic carbon sources for triacylglycerol and starch accumulation in Chlamydomonas reinhardtii.

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Gardner, Robert D; Lohman, Egan; Gerlach, Robin; Cooksey, Keith E; Peyton, Brent M

2013-01-01

Microalgae are capable of accumulating high levels of lipids and starch as carbon storage compounds. Investigation into the metabolic activities involved in the synthesis of these compounds has escalated since these compounds can be used as precursors for food and fuel. Here, we detail the results of a comprehensive analysis of Chlamydomonas reinhardtii using high or low inorganic carbon concentrations and speciation between carbon dioxide and bicarbonate, and the effects these have on inducing lipid and starch accumulation during nitrogen depletion. High concentrations of CO(2) (5%; v/v) produced the highest amount of biofuel precursors, transesterified to fatty acid methyl esters, but exhibited rapid accumulation and degradation characteristics. Low CO(2) (0.04%; v/v) caused carbon limitation and minimized triacylglycerol (TAG) and starch accumulation. High bicarbonate caused a cessation of cell cycling and accumulation of both TAG and starch that was more stable than the other experimental conditions. Starch accumulated prior to TAG and then degraded as maximum TAG was reached. This suggests carbon reallocation from starch-based to TAG-based carbon storage. Copyright © 2012 Wiley Periodicals, Inc.

Morphological aspects of starch and cell wall material mobilization in developing lupine cotyledons and the effect of kinetin on these processes

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Fortunat Młodzianowski

2015-01-01

Full Text Available In the cotyledons of dry lupine seeds the presence of starch was not demonstrated. Its formation during seed imbibition in darkness is accompanied by a reduction in the thickness of cell walls containing hemicelluloses. It is believed that the products of hemicellulose hydrolysis, particullarily in isolated cotyledons, arę the main source of materials for the synthesis of starch, In the process of cell wall decomposition the invaginations of plasmalemma appear to be involved. Kinetin enhance the hydrolysis of cell walls and the mobilization of starch in isolated cotyledons.

Resistant starch in cassava products

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Bruna Letícia Buzati Pereira

2014-06-01

Full Text Available Found in different foods, starch is the most important source of carbohydrates in the diet. Some factors present in starchy foods influence the rate at which the starch is hydrolyzed and absorbed in vivo. Due the importance of cassava products in Brazilian diet, the objective of this study was to analyze total starch, resistant starch, and digestible starch contents in commercial cassava products. Thirty three commercial cassava products from different brands, classifications, and origin were analyzed. The method used for determination of resistant starch consisted of an enzymatic process to calculate the final content of resistant starch considering the concentration of glucose released and analyzed. The results showed significant differences between the products. Among the flours and seasoned flours analyzed, the highest levels of resistant starch were observed in the flour from Bahia state (2.21% and the seasoned flour from Paraná state (1.93%. Starch, tapioca, and sago showed levels of resistant starch ranging from 0.56 to 1.1%. The cassava products analyzed can be considered good sources of resistant starch; which make them beneficial products to the gastrointestinal tract.

Synthesis and property characterization of cassava starch grafted poly(acrylamide-co-(maleic acid)) superabsorbent via γ-irradiation

International Nuclear Information System (INIS)

Kiatkamjornwong, Suda; Mongkolsawat, Kanlaya; Sonsuk, Manit

2004-01-01

Graft copolymerizations of acrylamide and maleic acid onto cassava starch by a simultaneous irradiation technique using γ-rays as a initiator were carried out. Various important parameters of total dose, dose rate, monomer-to-cassava starch ratio and maleic acid content were studied. Addition of 2% ww -1 diprotic acid of maleic acid into the reaction mixture yields a saponified starch graft copolymer with a water absorption in distilled water as high as 2256g g -1 of its dried weight. The water absorption of these saponified graft copolymers insaline and buffer solutions was also measured. The water absorption depends largely on the cationic type and concentration of these solutions in terms of ionic strength. This research explains a charge transfer mechanism for graft copolymerization of maleic acid and acrylamide onto cassava starch, and describes the influential parameters that affect grafting efficiency and water absorption. (author)

Milk production and composition responds to dietary neutral detergent fiber and starch ratio in dairy cows.

Science.gov (United States)

Zhao, Meng; Bu, Dengpan; Wang, Jiaqi; Zhou, Xiaoqiao; Zhu, Dan; Zhang, Ting; Niu, Junli; Ma, Lu

2016-06-01

This study was designed to investigate whether dietary neutral detergent fiber (NDF) : starch ratio could be considered as a nutritional indicator to evaluate carbohydrate composition and manipulate milk production and composition synthesis. Eight primiparous dairy cows were assigned to four total mixed rations with NDF : starch ratios of 0.86, 1.18, 1.63 and 2.34 from T1 to T4 in a replicated 4 × 4 Latin square design. Dry matter intake and milk production were decreased from T1 to T4. Digestibility of dry matter, organic matter, NDF and crude protein were linearly decreased from T1 to T4. As NDF : starch ratio increased, milk protein content and production, and milk lactose content and production were linearly reduced. However, milk fat content was linearly increased from T1 to T4. Quadratic effect was observed on milk fat production with the highest level in T3. Averaged rumen pH was linearly increased from T1 to T4, and subacute rumen acidosis occurred in T1. Ruminal propionate and butyrate concentration were linearly decreased, and microbial crude protein and metabolizable protein decreased from T1 to T4. It is concluded that NDF : starch ratio can be considered as a potential indicator to evaluate dietary carbohydrate composition and manipulate milk production and composition synthesis. © 2015 Japanese Society of Animal Science.

In vitro digestibility of banana starch cookies.

Science.gov (United States)

Bello-Pérez, Luis A; Sáyago-Ayerdi, Sonia G; Méndez-Montealvo, Guadalupe; Tovar, Juscelino

2004-01-01

Banana starch was isolated and used for preparation of two types of cookies. Chemical composition and digestibility tests were carried out on banana starch and the food products, and these results were compared with corn starch. Ash, protein, and fat levels in banana starch were higher than in corn starch. The high ash amount in banana starch could be due to the potassium content present in this fruit. Proximal analysis was similar between products prepared with banana starch and those based on corn starch. The available starch content of the banana starch preparation was 60% (dmb). The cookies had lower available starch than the starches while banana starch had lower susceptibility to the in vitro alpha-amylolysis reaction. Banana starch and its products had higher resistant starch levels than those made with corn starch.

Effects of cooking methods and starch structures on starch hydrolysis rates of rice.

Science.gov (United States)

Reed, Michael O; Ai, Yongfeng; Leutcher, Josh L; Jane, Jay-lin

2013-07-01

This study aimed to understand effects of different cooking methods, including steamed, pilaf, and traditional stir-fried, on starch hydrolysis rates of rice. Rice grains of 3 varieties, japonica, indica, and waxy, were used for the study. Rice starch was isolated from the grain and characterized. Amylose contents of starches from japonica, indica, and waxy rice were 13.5%, 18.0%, and 0.9%, respectively. The onset gelatinization temperature of indica starch (71.6 °C) was higher than that of the japonica and waxy starch (56.0 and 56.8 °C, respectively). The difference was attributed to longer amylopectin branch chains of the indica starch. Starch hydrolysis rates and resistant starch (RS) contents of the rice varieties differed after they were cooked using different methods. Stir-fried rice displayed the least starch hydrolysis rate followed by pilaf rice and steamed rice for each rice variety. RS contents of freshly steamed japonica, indica, and waxy rice were 0.7%, 6.6%, and 1.3%, respectively; those of rice pilaf were 12.1%, 13.2%, and 3.4%, respectively; and the stir-fried rice displayed the largest RS contents of 15.8%, 16.6%, and 12.1%, respectively. Mechanisms of the large RS contents of the stir-fried rice were studied. With the least starch hydrolysis rate and the largest RS content, stir-fried rice would be a desirable way of preparing rice for food to reduce postprandial blood glucose and insulin responses and to improve colon health of humans. © 2013 Institute of Food Technologists®

Cloning, characterisation and comparative analysis of a starch synthase IV gene in wheat: functional and evolutionary implications

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Broglie Karen E

2008-09-01

Full Text Available Abstract Background Starch is of great importance to humans as a food and biomaterial, and the amount and structure of starch made in plants is determined in part by starch synthase (SS activity. Five SS isoforms, SSI, II, III, IV and Granule Bound SSI, have been identified, each with a unique catalytic role in starch synthesis. The basic mode of action of SSs is known; however our knowledge of several aspects of SS enzymology at the structural and mechanistic level is incomplete. To gain a better understanding of the differences in SS sequences that underscore their specificity, the previously uncharacterised SSIVb from wheat was cloned and extensive bioinformatics analyses of this and other SSs sequences were done. Results The wheat SSIV cDNA is most similar to rice SSIVb with which it shows synteny and shares a similar exon-intron arrangement. The wheat SSIVb gene was preferentially expressed in leaf and was not regulated by a circadian clock. Phylogenetic analysis showed that in plants, SSIV is closely related to SSIII, while SSI, SSII and Granule Bound SSI clustered together and distinctions between the two groups can be made at the genetic level and included chromosomal location and intron conservation. Further, identified differences at the amino acid level in their glycosyltransferase domains, predicted secondary structures, global conformations and conserved residues might be indicative of intragroup functional associations. Conclusion Based on bioinformatics analysis of the catalytic region of 36 SSs and 3 glycogen synthases (GSs, it is suggested that the valine residue in the highly conserved K-X-G-G-L motif in SSIII and SSIV may be a determining feature of primer specificity of these SSs as compared to GBSSI, SSI and SSII. In GBSSI, the Ile485 residue may partially explain that enzyme's unique catalytic features. The flexible 380s Loop in the starch catalytic domain may be important in defining the specificity of action for each

[14C]sucrose uptake and labeling of starch in developing grains of normal segl barley

International Nuclear Information System (INIS)

Felker, F.C.; Peterson, D.M.; Nelson, O.E.

1984-01-01

Previous work showed that the segl mutant of barley (Hordeum vulgare o Betzes) did not differ from normal Betzes in plant growth, photosynthesis, or fertility, but it produced only shrunken seeds regardless of pollen source. To determine whether defects in sucrose uptake or starch synthesis resulted in the shrunken condition, developing grains of Betzes and segl were cultured in [ 14 C]sucrose solutions after slicing transversely to expose the endosperm cavity and free space. In both young grains (before genotypes differed in dry weight) and older grains (17 days after anthesis, when segl grains were smaller than Betzes), sucrose uptake and starch synthesis were similar in both genotypes on a dry weight basis. To determine if sucrose was hydrolyzed during uptake, spikes of Betzes and segl were allowed to take up [fructose-U- 14 C]sucrose 14 days after anthesis and the radioactivity of endosperm sugars was examined during 3 hours of incubation. Whereas less total radioactivity entered the endosperm and the endosperm cavity (free space) of segl, in both genotypes over 96% of the label of endosperm sugars was in sucrose, and there was no apparent initial or progressive randomization of label among hexose moieties of sucrose as compared to the free space sampled after 1 hour of incubation. The authors conclude that segl endosperms are capable of normal sucrose uptake and starch synthesis and that hydrolysis of sucrose is not required for uptake in either genotype. Evidence suggests abnormal development of grain tissue of maternal origin during growth of segl grains

Hydrolysis of native and heat-treated starches at sub-gelatinization temperature using granular starch hydrolyzing enzyme.

Science.gov (United States)

Uthumporn, U; Shariffa, Y N; Karim, A A

2012-03-01

The effect of heat treatment below the gelatinization temperature on the susceptibility of corn, mung bean, sago, and potato starches towards granular starch hydrolysis (35°C) was investigated. Starches were hydrolyzed in granular state and after heat treatment (50°C for 30 min) by using granular starch hydrolyzing enzyme for 24 h. Hydrolyzed heat-treated starches showed a significant increase in the percentage of dextrose equivalent compared to native starches, respectively, with corn 53% to 56%, mung bean 36% to 47%, sago 15% to 26%, and potato 12% to 15%. Scanning electron microscopy micrographs showed the presence of more porous granules and surface erosion in heat-treated starch compared to native starch. X-ray analysis showed no changes but with sharper peaks for all the starches, suggested that hydrolysis occurred on the amorphous region. The amylose content and swelling power of heat-treated starches was markedly altered after hydrolysis. Evidently, this enzyme was able to hydrolyze granular starches and heat treatment before hydrolysis significantly increased the degree of hydrolysis.

Myostatin inhibits eEF2K-eEF2 by regulating AMPK to suppress protein synthesis.

Science.gov (United States)

Deng, Zhao; Luo, Pei; Lai, Wen; Song, Tongxing; Peng, Jian; Wei, Hong-Kui

2017-12-09

Growth of skeletal muscle is dependent on the protein synthesis, and the rate of protein synthesis is mainly regulated in the stage of translation initiation and elongation. Myostatin, a member of the transforming growth factor-β (TGF-β) superfamily, is a negative regulator of protein synthesis. C2C12 myotubes was incubated with 0, 0.01, 0.1, 1, 2, 3 μg/mL myostatin recombinant protein, and then we detected the rates of protein synthesis by the method of SUnSET. We found that high concentrations of myostatin (2 and 3 μg/mL) inhibited protein synthesis by blocking mTOR and eEF2K-eEF2 pathway, while low concentration of myostatin (0.01, 0.1 and 1 μg/mL) regulated eEF2K-eEF2 pathway activity to block protein synthesis without affected mTOR pathway, and myostatin inhibited eEF2K-eEF2 pathway through regulating AMPK pathway to suppress protein synthesis. It provided a new mechanism for myostatin regulating protein synthesis and treating muscle atrophy. Copyright © 2017. Published by Elsevier Inc.

Starches, Sugars and Obesity

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Erik E. J. G. Aller

2011-03-01

Full Text Available The rising prevalence of obesity, not only in adults but also in children and adolescents, is one of the most important public health problems in developed and developing countries. As one possible way to tackle obesity, a great interest has been stimulated in understanding the relationship between different types of dietary carbohydrate and appetite regulation, body weight and body composition. The present article reviews the conclusions from recent reviews and meta-analyses on the effects of different starches and sugars on body weight management and metabolic disturbances, and provides an update of the most recent studies on this topic. From the literature reviewed in this paper, potential beneficial effects of intake of starchy foods, especially those containing slowly-digestible and resistant starches, and potential detrimental effects of high intakes of fructose become apparent. This supports the intake of whole grains, legumes and vegetables, which contain more appropriate sources of carbohydrates associated with reduced risk of cardiovascular and other chronic diseases, rather than foods rich in sugars, especially in the form of sugar-sweetened beverages.

Mechanical properties and solubility in water of corn starch-collagen composite films: Effect of starch type and concentrations.

Science.gov (United States)

Wang, Kun; Wang, Wenhang; Ye, Ran; Liu, Anjun; Xiao, Jingdong; Liu, Yaowei; Zhao, Yana

2017-02-01

This study investigated the possibility of enhancing the properties of collagen with three different maize starches: waxy maize starch, normal starch, and high amylose starch. Scanning electron microscopy images revealed that starch-collagen films had a rougher surface compared to pure collagen films which became smoother upon heating. Amylose starch and normal starch increased the tensile strength of unheated collagen films in both dry and wet states, while all starches increased tensile strength of collagen film by heating. Depending upon the amylose content and starch concentrations, film solubility in water decreased with the addition of starch. DSC thermograms demonstrated that addition of all starches improved the thermal stability of the collagen film. Moreover, X-ray diffraction results indicated that except for high amylose starch, the crystallinity of both starch and collagen was significantly decreased when subject to heating. FTIR spectra indicated that intermolecular interactions between starch and collagen were enhanced upon heating. Copyright © 2016 Elsevier Ltd. All rights reserved.

Properties of retrograded and acetylated starch produced via starch extrusion or starch hydrolysis with pullulanase.

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Kapelko, M; Zięba, T; Gryszkin, A; Styczyńska, M; Wilczak, A

2013-09-12

The aim of the present study was to determine the impact of serial modifications of starch, including firstly starch extrusion or hydrolysis with pullulanase, followed by retrogradation (through freezing and defrosting of pastes) and acetylation (under industrial conditions), on its susceptibility to amylolysis. The method of production had a significant effect on properties of the resultant preparations, whilst the direction and extent of changes depended on the type of modification applied. In the produced starch esters, the degree of substitution, expressed by the per cent of acetylation, ranged from 3.1 to 4.4 g/100 g. The acetylation had a significant impact on contents of elements determined with the atomic emission spectrometry, as it contributed to an increased Na content and decreased contents of Ca and K. The DSC thermal characteristics enabled concluding that the modifications caused an increase in temperatures and a decrease in heat of transition (or its lack). The acetylation of retrograded starch preparations increased their solubility in water and water absorbability. The modifications were found to exert various effects on the rheological properties of pastes determined based on the Brabender's pasting characteristics and flow curves determined with the use of an oscillatory-rotating viscosimeter. All starch acetates produced were characterized by ca. 40% resistance to amylolysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

Transcriptional transitions in Nicotiana benthamiana leaves upon induction of oil synthesis by WRINKLED1 homologs from diverse species and tissues.

Science.gov (United States)

Grimberg, Åsa; Carlsson, Anders S; Marttila, Salla; Bhalerao, Rishikesh; Hofvander, Per

2015-08-08

Carbon accumulation and remobilization are essential mechanisms in plants to ensure energy transfer between plant tissues with different functions or metabolic needs and to support new generations. Knowledge about the regulation of carbon allocation into oil (triacylglycerol) in plant storage tissue can be of great economic and environmental importance for developing new high-yielding oil crops. Here, the effect on global gene expression as well as on physiological changes in leaves transiently expressing five homologs of the transcription factor WRINKLED1 (WRI1) originating from diverse species and tissues; Arabidopsis thaliana and potato (Solanum tuberosum) seed embryo, poplar (Populus trichocarpa) stem cambium, oat (Avena sativa) grain endosperm, and nutsedge (Cyperus esculentus) tuber parenchyma, were studied by agroinfiltration in Nicotiana benthamiana. All WRI1 homologs induced oil accumulation when expressed in leaf tissue. Transcriptome sequencing revealed that all homologs induced the same general patterns with a drastic shift in gene expression profiles of leaves from that of a typical source tissue to a source-limited sink-like tissue: Transcripts encoding enzymes for plastid uptake and metabolism of phosphoenolpyruvate, fatty acid and oil biosynthesis were up-regulated, as were also transcripts encoding starch degradation. Transcripts encoding enzymes in photosynthesis and starch synthesis were instead down-regulated. Moreover, transcripts representing fatty acid degradation were up-regulated indicating that fatty acids might be degraded to feed the increased need to channel carbons into fatty acid synthesis creating a futile cycle. RT-qPCR analysis of leaves expressing Arabidopsis WRI1 showed the temporal trends of transcripts selected as 'markers' for key metabolic pathways one to five days after agroinfiltration. Chlorophyll fluorescence measurements of leaves expressing Arabidopsis WRI1 showed a significant decrease in photosynthesis, even though

Proteomic and functional analyses reveal MAPK1 regulates milk protein synthesis.

Science.gov (United States)

Lu, Li-Min; Li, Qing-Zhang; Huang, Jian-Guo; Gao, Xue-Jun

2012-12-27

L-Lysine (L-Lys) is an essential amino acid that plays fundamental roles in protein synthesis. Many nuclear phosphorylated proteins such as Stat5 and mTOR regulate milk protein synthesis. However, the details of milk protein synthesis control at the transcript and translational levels are not well known. In this current study, a two-dimensional gel electrophoresis (2-DE)/MS-based proteomic technology was used to identify phosphoproteins responsible for milk protein synthesis in dairy cow mammary epithelial cells (DCMECs). The effect of L-Lys on DCMECs was analyzed by CASY technology and reversed phase high performance liquid chromatography (RP-HPLC). The results showed that cell proliferation ability and β-casein expression were enhanced in DCMECs treated with L-Lys. By phosphoproteomics analysis, six proteins, including MAPK1, were identified up-expressed in DCMECs treated with 1.2 mM L-Lys for 24 h, and were verified by quantitative real-time PCR (qRT-PCR) and western blot. Overexpression and siRNA inhibition of MAPK1 experiments showed that MAPK1 upregulated milk protein synthesis through Stat5 and mTOR pathway. These findings that MAPK1 involves in regulation of milk synthesis shed new insights for understanding the mechanisms of milk protein synthesis.

DMPD: Mechanism of age-associated up-regulation in macrophage PGE2 synthesis. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 15331118 Mechanism of age-associated up-regulation in macrophage PGE2 synthesis. Wu...e-associated up-regulation in macrophage PGE2 synthesis. PubmedID 15331118 Title Mechanism of age-associated... up-regulation in macrophage PGE2 synthesis. Authors Wu D, Meydani SN. Publicatio

Comparison of gamma radiation effects on natural corn and potato starches and modified cassava starch

Science.gov (United States)

Teixeira, Bruna S.; Garcia, Rafael H. L.; Takinami, Patricia Y. I.; del Mastro, Nelida L.

2018-01-01

The objective of this work was to evaluate the effect of irradiation treatment on physicochemical properties of three natural polymers, i.e. native potato and corn starches and a typical Brazilian product, cassava starch modified through fermentation -sour cassava- and also to prepare composite hydrocolloid films based on them. Starches were irradiated in a 60Co irradiation chamber in doses up to 15 kGy, dose rate about 1 kGy/h. Differences were found in granule size distribution upon irradiation, mainly for corn and cassava starch but radiation did not cause significant changes in granule morphology. The viscosity of the potato, corn and cassava starches hydrogels decreased as a function of absorbed dose. Comparing non-irradiated and irradiated starches, changes in the Fourier transform infrared (FTIR) spectra in the 2000-1500 cm-1 region for potato and corn starches were observed but not for the cassava starch. Maximum rupture force of the starch-based films was affected differently for each starch type; color analysis showed that doses of 15 kGy promoted a slight rise in the parameter b* (yellow color) while the parameter L* (lightness) was not significantly affected; X-ray diffraction patterns remained almost unchanged by irradiation.

Sugarcane starch: quantitative determination and characterization

Directory of Open Access Journals (Sweden)

Joelise de Alencar Figueira

2011-09-01

Full Text Available Starch is found in sugarcane as a storage polysaccharide. Starch concentrations vary widely depending on the country, variety, developmental stage, and growth conditions. The purpose of this study was to determine the starch content in different varieties of sugarcane, between May and November 2007, and some characteristics of sugarcane starch such as structure and granules size; gelatinization temperature; starch solution filterability; and susceptibility to glucoamylase, pullulanase, and commercial bacterial and fungal α-amylase enzymes. Susceptibility to debranching amylolytic isoamylase enzyme from Flavobacterium sp. was also tested. Sugarcane starch had spherical shape with a diameter of 1-3 µm. Sugarcane starch formed complexes with iodine, which showed greater absorption in the range of 540 to 620 nm. Sugarcane starch showed higher susceptibility to glucoamylase compared to that of waxy maize, cassava, and potato starch. Sugarcane starch also showed susceptibility to debranching amylolytic pullulanases similar to that of waxy rice starch. It also showed susceptibility to α-amylase from Bacillus subtilis, Bacillus licheniformis, and Aspergillus oryzae similar to that of the other tested starches producing glucose, maltose, maltotriose, maltotetraose, maltopentose and limit α- dextrin.

Biotechnological potential of novel glycoside hydrolase family 70 enzymes synthesizing α-glucans from starch and sucrose

NARCIS (Netherlands)

Gangoiti, Joana; Pijning, Tjaard; Dijkhuizen, Lubbert

Transglucosidases belonging to the glycoside hydrolase (GH) family 70 are promising enzymatic tools for the synthesis of α-glucans with defined structures from renewable sucrose and starch substrates. Depending on the GH70 enzyme specificity, α-glucans with different structures and physicochemical

A Gibberellin-Mediated DELLA-NAC Signaling Cascade Regulates Cellulose Synthesis in Rice.

Science.gov (United States)

Huang, Debao; Wang, Shaogan; Zhang, Baocai; Shang-Guan, Keke; Shi, Yanyun; Zhang, Dongmei; Liu, Xiangling; Wu, Kun; Xu, Zuopeng; Fu, Xiangdong; Zhou, Yihua

2015-06-01

Cellulose, which can be converted into numerous industrial products, has important impacts on the global economy. It has long been known that cellulose synthesis in plants is tightly regulated by various phytohormones. However, the underlying mechanism of cellulose synthesis regulation remains elusive. Here, we show that in rice (Oryza sativa), gibberellin (GA) signals promote cellulose synthesis by relieving the interaction between SLENDER RICE1 (SLR1), a DELLA repressor of GA signaling, and NACs, the top-layer transcription factors for secondary wall formation. Mutations in GA-related genes and physiological treatments altered the transcription of CELLULOSE SYNTHASE genes (CESAs) and the cellulose level. Multiple experiments demonstrated that transcription factors NAC29/31 and MYB61 are CESA regulators in rice; NAC29/31 directly regulates MYB61, which in turn activates CESA expression. This hierarchical regulation pathway is blocked by SLR1-NAC29/31 interactions. Based on the results of anatomical analysis and GA content examination in developing rice internodes, this signaling cascade was found to be modulated by varied endogenous GA levels and to be required for internode development. Genetic and gene expression analyses were further performed in Arabidopsis thaliana GA-related mutants. Altogether, our findings reveal a conserved mechanism by which GA regulates secondary wall cellulose synthesis in land plants and provide a strategy for manipulating cellulose production and plant growth. © 2015 American Society of Plant Biologists. All rights reserved.

Starch Spherulites Prepared by a Combination of Enzymatic and Acid Hydrolysis of Normal Corn Starch.

Science.gov (United States)

Shang, Yaqian; Chao, Chen; Yu, Jinglin; Copeland, Les; Wang, Shuo; Wang, Shujun

2018-06-13

This paper describes a new method to prepare spherulites from normal corn starch by a combination of enzymatic (mixtures of α-amylase and amyloglucosidase) and acid hydrolysis followed by recrystallization of the hydrolyzed products. The resulting spherulites contained a higher proportion of chains with a degree of polymerization (DP) of 6-12 and a lower proportion of chains with DP of 25-36, compared to those of native starch. The spherulites had an even particle size of about 2 μm and a typical B-type crystallinity. The amounts of long- and short-range molecular order of double helices in starch spherulites were larger, but the quality of starch crystallites was poorer, compared to that of native starch. This study showed an efficient method for preparing starch spherulites with uniform granule morphology and small particle size from normal corn starch. The ratios of α-amylase and amyloglucosidase in enzymatic hydrolysis had little effect on the structure of the starch spherulites.

Biomimetic synthesis of calcium carbonate with different morphologies and polymorphs in the presence of bovine serum albumin and soluble starch.

Science.gov (United States)

Liu, Yuxi; Chen, Yuping; Huang, Xuechen; Wu, Gang

2017-10-01

Calcium carbonate has been synthesized by the reaction of Na 2 CO 3 and CaCl 2 in the presence of bovine serum albumin (BSA) and soluble starch. Effects of various bovine serum albumin (BSA) and soluble starch on the polymorph and morphology of CaCO 3 crystals were investigated. Crystallization of vaterite is favored in the presence of BSA and soluble starch, respectively, while calcite is favored in the presence of a mixture of BSA and soluble starch. The morphologies of CaCO 3 particles in the presence of mixture of BSA and soluble starch are mainly rod-like, suggesting that the BSA, soluble and their assemblies play key roles in stabilizing and directing the CaCO 3 crystal growth. Copyright © 2017. Published by Elsevier B.V.

Dilute solution properties of canary seed (Phalaris canariensis) starch in comparison to wheat starch.

Science.gov (United States)

Irani, Mahdi; Razavi, Seyed M A; Abdel-Aal, El-Sayed M; Hucl, Pierre; Patterson, Carol Ann

2016-06-01

Dilute solution properties of an unknown starch are important to understand its performance and applications in food and non-food industries. In this paper, rheological and molecular properties (intrinsic viscosity, molecular weight, shape factor, voluminosity, conformation and coil overlap parameters) of the starches from two hairless canary seed varieties (CO5041 & CDC Maria) developed for food use were evaluated in the dilute regime (Starch dispersions in DMSO (0.5g/dl)) and compared with wheat starch (WS). The results showed that Higiro model is the best among five applied models for intrinsic viscosity determination of canary seed starch (CSS) and WS on the basis of coefficient of determination (R(2)) and root mean square error (RMSE). WS sample showed higher intrinsic viscosity value (1.670dl/g) in comparison to CSS samples (1.325-1.397dl/g). Berry number and the slope of master curve demonstrated that CSS and WS samples were in dilute domain without entanglement occurrence. The shape factor suggested spherical and ellipsoidal structure for CO5041 starch and ellipsoidal for CDC Maria starch and WS. The molecular weight, coil radius and coil volume of CSSs were smaller than WS. The behavior and molecular characterization of canary seed starch showed its unique properties compared with wheat starch. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of waxy rice flour and cassava starch on freeze-thaw stability of rice starch gels.

Science.gov (United States)

Charoenrein, Sanguansri; Preechathammawong, Nutsuda

2012-10-01

Repeatedly frozen and thawed rice starch gel affects quality. This study investigated how incorporating waxy rice flour (WF) and cassava starch (CS) in rice starch gel affects factors used to measure quality. When rice starch gels containing 0-2% WF and CS were subjected to 5 freeze-thaw cycles, both WF and CS reduced the syneresis in first few cycles. However CS was more effective in reducing syneresis than WF. The different composite arrangement of rice starch with WF or CS caused different mechanisms associated with the rice starch gel retardation of retrogradation, reduced the spongy structure and lowered syneresis. Both swollen granules of rice starch and CS caused an increase in the hardness of the unfrozen and freeze-thawed starch gel while highly swollen WF granules caused softer gels. These results suggested that WF and CS were effective in preserving quality in frozen rice starch based products. Copyright © 2012 Elsevier Ltd. All rights reserved.

Thermomechanical treatment of starch

NARCIS (Netherlands)

Goot, van der A.J.; Einde, van den R.M.

2006-01-01

Starch is used as a major component in many food and nonfood applications and determines the overall product properties to a large extent. It is therefore important to understand the effect of processing on starch. Many starch-based products are produced using a thermal as well as a mechanical

Glycogenesis and de novo lipid synthesis from dietary starch in juvenile gilthead sea bream (Sparus aurata) quantified with stable isotopes

DEFF Research Database (Denmark)

Ekmann, Kim Schøn; Dalsgaard, Anne Johanne Tang; Holm, Jørgen

2013-01-01

the metabolic fate of dietary starch, 0·7% wheat starch was replaced with isotope-labelled starch (.98% 13C). Fish were fed the experimental diets for three consecutive 10 d periods, and isotope ratio MS was applied to quantify 13C enrichment of liver and whole-body glycogen and lipid pools over the three...

1.7 nm Platinum Nanoparticles: Synthesis with Glucose Starch, Characterization and Catalysis

DEFF Research Database (Denmark)

Engelbrekt, Christian; Sørensen, Karsten Holm; Lubcke, T.

2010-01-01

Monodisperse platinum nanoparticles (PtNPs) were synthesized by a green recipe. Glucose serves as a reducing agent and starch as a stabilization agent to protect the freshly formed PtNP cores in buffered aqueous solutions. Among the ten buffers studied, 2-(N-morpholino)ethanesulfonic acid (MES), ...

Structural basis for the roles of starch and sucrose in homo-exopolysaccharide formation by Lactobacillus reuteri 35-5.

Science.gov (United States)

Bai, Yuxiang; Dobruchowska, Justyna M; van der Kaaij, Rachel M; Gerwig, Gerrit J; Dijkhuizen, Lubbert

2016-10-20

Lactic acid bacteria (LAB) produce exopolysaccharides (EPS) that are important for biofilm formation in the mammalian oral cavity and gastrointestinal tract. Sucrose is a well-known substrate for homo-EPS formation by Lactobacillus reuteri glucansucrases (GS). Starch is the main fermentable carbohydrate in the human diet, and often consumed simultaneously with sucrose. Recently we have characterized L. reuteri strains that also possess 4,6-α-glucanotransferases (4,6-α-GTases) that act on starch yielding isomalto-/malto-polysaccharides. In this study we have characterized the EPS formed by L. reuteri 35-5 cells and enzymes from sucrose plus starch. The data show that both in vivo and in vitro the L. reuteri 35-5 GS and 4,6-α-GTase enzymes, incubated with sucrose plus starch, cross-react and contribute to synthesis of the final hybrid EPS products. This may have strong effects on the EPS functional properties, influence biofilm formation, and affect the relationship between dietary intake of sucrose and starch, and dental caries formation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Regulation of urea synthesis during the acute phase response in rats

DEFF Research Database (Denmark)

Thomsen, Karen Louise; Jessen, Niels; Buch Møller, Andreas

2013-01-01

The acute-phase response is a catabolic event involving increased waste of amino-nitrogen (N) via hepatic urea synthesis, despite an increased need for amino-N incorporation into acute-phase proteins. This study aimed to clarify the regulation of N elimination via urea during different phases...... of the tumor necrosis factor-α (TNF-α)-induced acute-phase response in rats. We used four methods to study the regulation of urea synthesis: We examined urea cycle enzyme mRNA levels in liver tissue, the hepatocyte urea cycle enzyme proteins, the in vivo capacity of urea-N synthesis (CUNS), and known humoral...... regulators of CUNS at 1, 3, 24, and 72 h after TNF-α injection (25 μg/kg iv rrTNF-α) in rats. Serum acute-phase proteins and their liver mRNA levels were also measured. The urea cycle enzyme mRNA levels acutely decreased and then gradually normalized, whereas the urea cycle enzyme proteins remained...

Physicochemical properties of maca starch.

Science.gov (United States)

Zhang, Ling; Li, Guantian; Wang, Sunan; Yao, Weirong; Zhu, Fan

2017-03-01

Maca (Lepidium meyenii Walpers) is gaining research attention due to its unique bioactive properties. Starch is a major component of maca roots, thus representing a novel starch source. In this study, the properties of three maca starches (yellow, purple and black) were compared with commercially maize, cassava, and potato starches. The starch granule sizes ranged from 9.0 to 9.6μm, and the granules were irregularly oval. All the maca starches presented B-type X-ray diffraction patterns, with the relative degree of crystallinity ranging from 22.2 to 24.3%. The apparent amylose contents ranged from 21.0 to 21.3%. The onset gelatinization temperatures ranged from 47.1 to 47.5°C as indicated by differential scanning calorimetry. Significant differences were observed in the pasting properties and textural parameters among all of the studied starches. These characteristics suggest the utility of native maca starch in products subjected to low temperatures during food processing and other industrial applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Functional properties of irradiated starch

International Nuclear Information System (INIS)

Laouini, Wissal

2011-01-01

Irradiation is an effective method capable of modifying the functional properties of starches. Its effect depends on the specific structural and molecular organization of starch granules from different botanical sources. In this study, we have studied the effect of gamma irradiation (3, 5, 10, 20, 35, 50 kGy) on the rheological properties of some varieties of starch (potato, cassava and wheat). First, we were interested in determining dry matter content; the results showed that the variation in dry matter compared to the control (native starch) is almost zero. So it does not depend on the dose of irradiation. Contrariwise, it differs from a botanical species to another. The viscometer has shown that these starches develop different behaviors during shearing. The native potato starch gave the highest viscosity followed by wheat and cassava which have almost similar viscosities. For all varieties, the viscosity of starch decreases dramatically with an increasing dose of irradiation. At high doses (35 and 50 kGy) the behavior of different starch is similar to that of a viscous pure liquid. The textural analysis via the back-extrusion test showed that increasing the dose of radiation causes a decrease in extrusion force and the energy spent of the different starch throughout the test. Indeed, the extrusion resistance decreases with increasing dose.

Mixture design of rice flour, maize starch and wheat starch for optimization of gluten free bread quality.

Science.gov (United States)

Mancebo, Camino M; Merino, Cristina; Martínez, Mario M; Gómez, Manuel

2015-10-01

Gluten-free bread production requires gluten-free flours or starches. Rice flour and maize starch are two of the most commonly used raw materials. Over recent years, gluten-free wheat starch is available on the market. The aim of this research was to optimize mixtures of rice flour, maize starch and wheat starch using an experimental mixture design. For this purpose, dough rheology and its fermentation behaviour were studied. Quality bread parameters such as specific volume, texture, cell structure, colour and acceptability were also analysed. Generally, starch incorporation reduced G* and increased the bread specific volume and cell density, but the breads obtained were paler than the rice flour breads. Comparing the starches, wheat starch breads had better overall acceptability and had a greater volume than maize-starch bread. The highest value for sensorial acceptability corresponded to the bread produced with a mixture of rice flour (59 g/100 g) and wheat starch (41 g/100 g).

STARCH SULFURIC ACID: AN ALTERNATIVE, ECO-FRIENDLY CATALYST FOR BIGINELLI REACTION

Directory of Open Access Journals (Sweden)

Ramin Rezaei

2013-12-01

Full Text Available The one-pot multicomponent synthesis of 3,4-dihydropyrimidinone derivatives using starch sulfuric acid as an environmentally friendly biopolymer-based solid acid catalyst from aldehydes, β-keto esters and urea/ thiourea without solvent is described. Compared with classical Biginelli reaction conditions, this new method has the advantage of minimizing the cost operational hazards and environmental pollution, good yields, shorter reaction times and simple work-up.

Characterization of starch nanoparticles

Science.gov (United States)

Szymońska, J.; Targosz-Korecka, M.; Krok, F.

2009-01-01

Nanomaterials already attract great interest because of their potential applications in technology, food science and medicine. Biomaterials are biodegradable and quite abundant in nature, so they are favoured over synthetic polymer based materials. Starch as a nontoxic, cheap and renewable raw material is particularly suitable for preparation of nanoparticles. In the paper, the structure and some physicochemical properties of potato and cassava starch particles of the size between 50 to 100 nm, obtained by mechanical treatment of native starch, were presented. We demonstrated, with the aim of the Scanning Electron Microscopy (SEM) and the non-contact Atomic Force Microscopy (nc-AFM), that the shape and dimensions of the obtained nanoparticles both potato and cassava starch fit the blocklets - previously proposed as basic structural features of native starch granules. This observation was supported by aqueous solubility and swelling power of the particles as well as their iodine binding capacity similar to those for amylopectin-type short branched polysaccharide species. Obtained results indicated that glycosidic bonds of the branch linkage points in the granule amorphous lamellae might be broken during the applied mechanical treatment. Thus the released amylopectin clusters could escape out of the granules. The starch nanoparticles, for their properties qualitatively different from those of native starch granules, could be utilized in new applications.

Starch Bioengineering in Barley

DEFF Research Database (Denmark)

Shaik, Shahnoor Sultana

, the effects of engineering high levels of phosphate and amylose content on starch physico-chemical properties were evaluated by various biochemical and morphological studies. As a result, a substantial increase of 10-fold phosphate content and ~99% amylose content with high-resistant starch was observed...... in storage reserve accumulation, metabolite accumulation in AO but no significant differences were observed in HP compared to WT. Scanning electron microscopy and confocal microscopy revealed the details in topography and internal structures of the starch granules in these lines. The results demonstrated......Starch represents the most important carbohydrate used for food and feed purposes. Increasingly, it is also used as a renewable raw material, as a source of biofuel, and for many different industrial applications. Progress in understanding starch biosynthesis, and investigations of the genes...

Future cereal starch bioengineering

DEFF Research Database (Denmark)

Blennow, Andreas; Jensen, Susanne Langgård; Shaik, Shahnoor Sultana

2013-01-01

The importance of cereal starch production worldwide cannot be overrated. However, the qualities and resulting values of existing raw and processed starch do not fully meet future demands for environmentally friendly production of renewable, advanced biomaterials, functional foods, and biomedical...... additives. New approaches for starch bioengineering are needed. In this review, we discuss cereal starch from a combined universal bioresource point of view. The combination of new biotechniques and clean technology methods can be implemented to replace, for example, chemical modification. The recently...... released cereal genomes and the exploding advancement in whole genome sequencing now pave the road for identifying new genes to be exploited to generate a multitude of completely new starch functionalities directly in the cereal grain, converting cereal crops to production plants. Newly released genome...

The influence of starch molecular mass on the properties of extruded thermoplastic starch

NARCIS (Netherlands)

Vliegenthart, J.F.G.; Soest, J.J.G. van; Benes, K.; Wit, D. de

1996-01-01

The mechanical properties of a low and a high molecular mass thermoplastic starch (TPS) were monitored at water contents in the range of 5–30% (w/w). The granular starches were plasticized by extrusion processing with glycerol and water. The low molecular mass starch was prepared by partial acid

Process for the production of starch and alcohol from substances containing starch

Energy Technology Data Exchange (ETDEWEB)

Smith, N B; McFate, H A; Eubanks, E M

1969-01-01

Almost complete extraction of starch from wheat, rice, maize, etc., is achieved more economically then by conventional processes. Starch-containing cereal is soaked, the magma is broken and the seed removed. The magma is then drained and separated into a liquid filtrate consisting of starch, gluten and fine fibers, and a solid residue made up of coarse fibers, husks and grit. The liquid filtrate is sieved to remove the fine fibers, and then centrifuged to obtain pure, gluten-free starch. The solid residue is treated with a mineral acid in a converter to give sugar, thus forming a material which is fermented and distilled to give alcohol.

Preliminary Study on the Synthesis of Phosphorylated Mung Bean Starch: The Effect of pH on the Physicochemical and Functional Properties

Directory of Open Access Journals (Sweden)

Illona Nathania

2017-11-01

Full Text Available Mung bean (Vigna radiate L. is a grain legume widely cultivated in tropical and sub-tropical regions. Mung bean seeds contain a significant amount of carbohydrate (63%-w/w and are easily digested compared to seeds from other legumes. Mung bean starch has the potential to be used as thickener or gelling agents in food industries. Certain functional properties of mung bean starch, however, still need to be improved. In this research, a preliminary study was performed to upgrade mung bean starch properties using phosphorylation reaction. In particular, the effect of starch suspension pH (6–10 on the functional properties of the modified products was investigated. Phosphorylation was carried out at 130 °C, for 2 h using sodium tripolyphosphate (STPP with an intake of 5%-w based on dry starch. The phosphorylated products were subsequently washed with water and dried. The experimental results show that the P-content of the phosphorylated mung bean starch is accessible in the range of 0.04–0.08%. The solubility (6.09–11.37%-w/w and swelling power (9.88–11.17 g/g of the modified starch products have been improved compared to native starch (solubility = 6.06 %-w/w, swelling power = 8.05 g/g. Phosphorylation also proved to increase peak viscosity, paste clarity, and water absorption/oil absorption capacity of the products.

Starch degradation by irradiation

International Nuclear Information System (INIS)

Pruzinec, J.; Hola, O.

1987-01-01

The effect of high energy irradiation on various starch samples was studied. The radiation dose varied between 43 and 200.9 kGy. The viscosity of starch samples were determined by Hoeppler's method. The percentual solubility of the matter in dry starch was evaluated. The viscosity and solubility values are presented. (author) 14 refs

Preparation of hydroxypropyl corn and amaranth starch hydrolyzate and its evaluation as wall material in microencapsulation.

Science.gov (United States)

Kshirsagar, Amol C; Singhal, Rekha S

2008-06-01

Hydroxypropylation of starches lends it useful physicochemical and functional properties that are industrially important. The literature on hydroxypropylation using organic solvents for obtaining higher molar substitution (MS) is scantily available. The present work reports on hydroxypropylation of corn and a waxy amaranth starch to different MS with propylene oxide in an alkaline-organic medium (isopropanol). The synthesis was followed in terms of MS. The parameters optimized were starch:isopropanol ratio (w/w), reaction temperature, reaction time and the quantity of alkali required in the process. A maximal MS of 0.180 and 0.162 were obtained for hydroxypropyl corn starch (HPSC) and hydroxypropyl amaranth starch (HPSA), respectively. Enzymatic hydrolysis of the HPSC and HPSA of the above MS was carried out on a 30% (w/v) solution at a pH of 6.5 and 95°C for varying time periods using 0.1% (w/w based on starch) bacterial α-amylase, termamyl. The hydrolysis was terminated by adjusting the pH to 3.5 using 0.1N HCl. The hydrolyzates were characterized in terms of dextrose equivalent and viscosity. The hydrolyzate obtained after 3h of hydrolysis was spray dried and compared to gum arabic with respect to encapsulation of model flavourings, orange oil and lemon oil. Copyright © 2007 Elsevier Ltd. All rights reserved.

Synthesis of thermoplastic starch-bacterial cellulose nanocomposites via in situ fermentation

OpenAIRE

Osorio, Marlon A.; Restrepo, David; Velásquez-Cock, Jorge A.; Zuluaga, Robin O.; Montoya, Ursula; Rojas, Orlando; Gañán, Piedad F.; Marin, Diana; Castro, Cristina I.

2014-01-01

In this paper, a nanocomposite based on thermoplastic starch (TPS) reinforced with bacterial cellulose (BC) nanoribbons was synthesized by in situ fermentation and chemical crosslinking. BC nanoribbons were produced by a Colombian native strain of Gluconacetobacter medellinensis; the nanocomposite was plasticized with glycerol and crosslinked with citric acid. The reinforcement percentage in the nanocomposites remained constant throughout the fermentation time because of the TPS absorption ca...

A Gibberellin-Mediated DELLA-NAC Signaling Cascade Regulates Cellulose Synthesis in Rice[OPEN

Science.gov (United States)

Huang, Debao; Wang, Shaogan; Zhang, Baocai; Shang-Guan, Keke; Shi, Yanyun; Zhang, Dongmei; Liu, Xiangling; Wu, Kun; Xu, Zuopeng; Fu, Xiangdong; Zhou, Yihua

2015-01-01

Cellulose, which can be converted into numerous industrial products, has important impacts on the global economy. It has long been known that cellulose synthesis in plants is tightly regulated by various phytohormones. However, the underlying mechanism of cellulose synthesis regulation remains elusive. Here, we show that in rice (Oryza sativa), gibberellin (GA) signals promote cellulose synthesis by relieving the interaction between SLENDER RICE1 (SLR1), a DELLA repressor of GA signaling, and NACs, the top-layer transcription factors for secondary wall formation. Mutations in GA-related genes and physiological treatments altered the transcription of CELLULOSE SYNTHASE genes (CESAs) and the cellulose level. Multiple experiments demonstrated that transcription factors NAC29/31 and MYB61 are CESA regulators in rice; NAC29/31 directly regulates MYB61, which in turn activates CESA expression. This hierarchical regulation pathway is blocked by SLR1-NAC29/31 interactions. Based on the results of anatomical analysis and GA content examination in developing rice internodes, this signaling cascade was found to be modulated by varied endogenous GA levels and to be required for internode development. Genetic and gene expression analyses were further performed in Arabidopsis thaliana GA-related mutants. Altogether, our findings reveal a conserved mechanism by which GA regulates secondary wall cellulose synthesis in land plants and provide a strategy for manipulating cellulose production and plant growth. PMID:26002868

Starch Biosynthesis in Crop Plants

Directory of Open Access Journals (Sweden)

Ian J. Tetlow

2018-05-01

Full Text Available Starch is a water-insoluble polyglucan synthesized inside the plastids of plant tissues to provide a store of carbohydrate. Starch harvested from plant storage organs has probably represented the major source of calories for the human diet since before the dawn of civilization. Following the advent of agriculture and the building of complex societies, humans have maintained their dependence on high-yielding domesticated starch-forming crops such as cereals to meet food demands, livestock production, and many non-food applications. The top three crops in terms of acreage are cereals, grown primarily for the harvestable storage starch in the endosperm, although many starchy tuberous crops also provide an important source of calories for various communities around the world. Despite conservation in the core structure of the starch granule, starches from different botanical sources show a high degree of variability, which is exploited in many food and non-food applications. Understanding the factors underpinning starch production and its final structure are of critical importance in guiding future crop improvement endeavours. This special issue contains reviews on these topics and is intended to be a useful resource for researchers involved in improvement of starch-storing crops.

Starch Origin and Thermal Processing Affect Starch Digestion in a Minipig Model of Pancreatic Exocrine Insufficiency.

Science.gov (United States)

Mößeler, Anne; Vagt, Sandra; Beyerbach, Martin; Kamphues, Josef

2015-01-01

Although steatorrhea is the most obvious symptom of pancreatic exocrine insufficiency (PEI), enzymatic digestion of protein and starch is also impaired. Low praecaecal digestibility of starch causes a forced microbial fermentation accounting for energy losses and meteorism. To optimise dietetic measures, knowledge of praecaecal digestibility of starch is needed but such information from PEI patients is rare. Minipigs fitted with an ileocaecal fistula with (n = 3) or without (n = 3) pancreatic duct ligation (PL) were used to estimate the rate of praecaecal disappearance (pcD) of starch. Different botanical sources of starch (rice, amaranth, potato, and pea) were fed either raw or cooked. In the controls (C), there was an almost complete pcD (>92%) except for potato starch (61.5%) which was significantly lower. In PL pcD of raw starch was significantly lower for all sources of starch except for amaranth (87.9%). Thermal processing increased pcD in PL, reaching values of C for starch from rice, potato, and pea. This study clearly underlines the need for precise specification of starch used for patients with specific dietetic needs like PEI. Data should be generated in suitable animal models or patients as tests in healthy individuals would not have given similar conclusions.

Starch Origin and Thermal Processing Affect Starch Digestion in a Minipig Model of Pancreatic Exocrine Insufficiency

Directory of Open Access Journals (Sweden)

Anne Mößeler

2015-01-01

Full Text Available Although steatorrhea is the most obvious symptom of pancreatic exocrine insufficiency (PEI, enzymatic digestion of protein and starch is also impaired. Low praecaecal digestibility of starch causes a forced microbial fermentation accounting for energy losses and meteorism. To optimise dietetic measures, knowledge of praecaecal digestibility of starch is needed but such information from PEI patients is rare. Minipigs fitted with an ileocaecal fistula with (n=3 or without (n=3 pancreatic duct ligation (PL were used to estimate the rate of praecaecal disappearance (pcD of starch. Different botanical sources of starch (rice, amaranth, potato, and pea were fed either raw or cooked. In the controls (C, there was an almost complete pcD (>92% except for potato starch (61.5% which was significantly lower. In PL pcD of raw starch was significantly lower for all sources of starch except for amaranth (87.9%. Thermal processing increased pcD in PL, reaching values of C for starch from rice, potato, and pea. This study clearly underlines the need for precise specification of starch used for patients with specific dietetic needs like PEI. Data should be generated in suitable animal models or patients as tests in healthy individuals would not have given similar conclusions.

Effect of maize starch concentration in the diet on starch and cell wall digestion in the dairy cow.

Science.gov (United States)

van Vuuren, A M; Hindle, V A; Klop, A; Cone, J W

2010-06-01

An in vivo experiment was performed to determine the effect of level of maize starch in the diet on digestion and site of digestion of organic matter, starch and neutral detergent fibre (NDF). In a repeated change-over design experiment, three cows fitted with a rumen cannula and T-piece cannulae in duodenum and ileum received a low-starch (12% of ration dry matter) and a high-starch (33% of ration dry matter) diet. Starch level was increased by exchanging dried sugar beet pulp by ground maize. After a 2-week adaptation period, feed intake, rumen fermentation parameters (in vivo and in situ), intestinal flows, faecal excretion of organic matter, starch and NDF were estimated. When the high-starch diet was fed, dry matter intake was higher (19.0 kg/day vs. 17.8 kg/day), and total tract digestibility of organic matter, starch and NDF was lower when the low-starch diet was fed. Maize starch concentration had no significant effect on rumen pH and volatile fatty acid concentration nor on the site of digestion of organic matter and starch and rate of passage of ytterbium-labelled forage. On the high-starch diet, an extra 1.3 kg of maize starch was supplied at the duodenum in relation to the low-starch diet, but only an extra 0.3 kg of starch was digested in the small intestine. Digestion of NDF was only apparent in the rumen and was lower on the high-starch diet than on the low-starch diet, mainly attributed to the reduction in sugar beet pulp in the high-starch diet. It was concluded that without the correction for the reduction in NDF digestion in the rumen, the extra supply of glucogenic (glucose and propionic acid) and ketogenic nutrients (acetic and butyric acid) by supplemented starch will be overestimated. The mechanisms responsible for these effects need to be addressed in feed evaluation.

Synthesis and application of labelled growth regulators

International Nuclear Information System (INIS)

Shyutte, G.R.

1982-01-01

For the investigation of the metabolism both of phytoeffectors like herbicides and plant growth regulators such compounds are needed in radioactive labelled form. The synthesis of radioactive labelled fluorodifen, nitrofen, ethephon, diphenylic acetic acid, 2,4-dichlorophenoxyisobutyric acid, abscisic acid, hydroxybenzoic acids and different conjugates are described. Some examples of these compounds metabolism in plants are discussed [ru

Effect of starch types on properties of biodegradable polymer based on thermoplastic starch process by injection molding technique

Directory of Open Access Journals (Sweden)

Yossathorn Tanetrungroj

2015-04-01

Full Text Available In this study effects of different starch types on the properties of biodegradable polymer based on thermoplastic starch (TPS were investigated. Different types of starch containing different contents of amylose and amylopectin were used, i.e. cassava starch, mungbean starch, and arrowroot starch. The TPS polymers were compounded and shaped using an internal mixer and an injection molding machine, respectively. It was found that the amount of amylose and amylopectin contents on native starch influence the properties of the TPS polymer. A high amylose starch of TPMS led to higher strength, hardness, degree of crystallization than the high amylopectin starch of TPCS. In addition, function group analysis by Fourier transforms infrared spectrophotometer, water absorption, and biodegradation by soil burial test were also examined.

Syndecan-2 regulates melanin synthesis via protein kinase C βII-mediated tyrosinase activation.

Science.gov (United States)

Jung, Hyejung; Chung, Heesung; Chang, Sung Eun; Choi, Sora; Han, Inn-Oc; Kang, Duk-Hee; Oh, Eok-Soo

2014-05-01

Syndecan-2, a transmembrane heparan sulfate proteoglycan that is highly expressed in melanoma cells, regulates melanoma cell functions (e.g. migration). Since melanoma is a malignant tumor of melanocytes, which largely function to synthesize melanin, we investigated the possible involvement of syndecan-2 in melanogenesis. Syndecan-2 expression was increased in human skin melanoma tissues compared with normal skin. In both mouse and human melanoma cells, siRNA-mediated knockdown of syndecan-2 was associated with reduced melanin synthesis, whereas overexpression of syndecan-2 increased melanin synthesis. Similar effects were also detected in human primary epidermal melanocytes. Syndecan-2 expression did not affect the expression of tyrosinase, a key enzyme in melanin synthesis, but instead enhanced the enzymatic activity of tyrosinase by increasing the membrane and melanosome localization of its regulator, protein kinase CβII. Furthermore, UVB caused increased syndecan-2 expression, and this up-regulation of syndecan-2 was required for UVB-induced melanin synthesis. Taken together, these data suggest that syndecan-2 regulates melanin synthesis and could be a potential therapeutic target for treating melanin-associated diseases. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Preparation and characterization of 1,6 anhydrous Β-D-Glucopyranose from starch

International Nuclear Information System (INIS)

Alvarez Lopez, M.S.

1991-01-01

In order to prepare 2-deoxi-2-fluoride-D-glucosa (2FDG) in an inert form there are several synthesis methods, but the more interesting one for our study is based in a reaction from the 1,6 anhydrous, Β-D-glucopyranose (1,6AGP), in an attempt to compare the labelling efficiency rate of 2FDG with F-18, which is highly used in nuclear medicine. In the present paper the attainment of starch from white potatoe, infrared analysis of this starch and fusion point are included. Also results are compared with an analytical reactive standard. The process of preparation of 1,6AGP by pyrolysis of starch under reduced pressure, its separation and purification by crystallization and infrared characterization of 1,6AGP, nuclear magnetic resonance and mass spectrometry are also included. 10 kg. of potatoes were used, and 93059 g. ±5.8 of starch with an efficiency rate of 9.32 ±0.631; fusion point was 272 o C and there was a 9.83 ± 1.48 % of humidity. After the pyrolysis, crystallization an purification processes, 1.71 ±0.54 % of 1,6AGP were obtained. Later results of compound characterization, nuclear magnetic resonance, infrared and mass spectrometry were compared with a commercial product and it was proved that it corresponds to such pure compound. (Author)

The influence of extruded starch molecular mass on the properties of extruded thermoplastic starch

NARCIS (Netherlands)

Soest, van J.J.G.; Benes, K.; Wit, de D.; Vliegenthart, J.F.G.

1996-01-01

The mechanical properties of a low and a high molecular mass thermoplastic starch (TPS) were monitored at water contents in the range of 5-30% (w/w). The granular starches were plasticized by extrusion processing with glycerol and water. The low molecular mass starch was prepared by partial acid

Chemical Modifications of Starch: Microwave Effect

Directory of Open Access Journals (Sweden)

Kamila Lewicka

2015-01-01

Full Text Available This paper presents basic methods of starch chemical modification, the effect of microwave radiation on the modification process, and the physicochemical properties of starch. It has been shown that the modifications contribute to improvement of the material performance and likewise to significant improvement of its mechanical properties. As a result, more and more extensive use of starch is possible in various industries. In addition, methods of oxidized starch and starch esters preparation are discussed. Properties of microwave radiation and its impact on starch (with particular regard to modifications described in literature are characterized.

Chemical Modifications of Starch: Microwave Effect

OpenAIRE

Lewicka, Kamila; Siemion, Przemysław; Kurcok, Piotr

2015-01-01

This paper presents basic methods of starch chemical modification, the effect of microwave radiation on the modification process, and the physicochemical properties of starch. It has been shown that the modifications contribute to improvement of the material performance and likewise to significant improvement of its mechanical properties. As a result, more and more extensive use of starch is possible in various industries. In addition, methods of oxidized starch and starch esters preparation ...

Roles of Transcriptional and Translational Control Mechanisms in Regulation of Ribosomal Protein Synthesis in Escherichia coli.

Science.gov (United States)

Burgos, Hector L; O'Connor, Kevin; Sanchez-Vazquez, Patricia; Gourse, Richard L

2017-11-01

Bacterial ribosome biogenesis is tightly regulated to match nutritional conditions and to prevent formation of defective ribosomal particles. In Escherichia coli , most ribosomal protein (r-protein) synthesis is coordinated with rRNA synthesis by a translational feedback mechanism: when r-proteins exceed rRNAs, specific r-proteins bind to their own mRNAs and inhibit expression of the operon. It was recently discovered that the second messenger nucleotide guanosine tetra and pentaphosphate (ppGpp), which directly regulates rRNA promoters, is also capable of regulating many r-protein promoters. To examine the relative contributions of the translational and transcriptional control mechanisms to the regulation of r-protein synthesis, we devised a reporter system that enabled us to genetically separate the cis -acting sequences responsible for the two mechanisms and to quantify their relative contributions to regulation under the same conditions. We show that the synthesis of r-proteins from the S20 and S10 operons is regulated by ppGpp following shifts in nutritional conditions, but most of the effect of ppGpp required the 5' region of the r-protein mRNA containing the target site for translational feedback regulation and not the promoter. These results suggest that most regulation of the S20 and S10 operons by ppGpp following nutritional shifts is indirect and occurs in response to changes in rRNA synthesis. In contrast, we found that the promoters for the S20 operon were regulated during outgrowth, likely in response to increasing nucleoside triphosphate (NTP) levels. Thus, r-protein synthesis is dynamic, with different mechanisms acting at different times. IMPORTANCE Bacterial cells have evolved complex and seemingly redundant strategies to regulate many high-energy-consuming processes. In E. coli , synthesis of ribosomal components is tightly regulated with respect to nutritional conditions by mechanisms that act at both the transcription and translation steps. In

Starch Granule Re-Structuring by Starch Branching Enzyme and Glucan Water Dikinase Modulation Affects Caryopsis Physiology and Metabolism

DEFF Research Database (Denmark)

Shaik, Shahnoor S.; Obata, Toshihiro; Hebelstrup, Kim H

2016-01-01

in starch granule morphology at maturity. The results demonstrate that decreasing the storage starch branching resulted in metabolic adjustments and re-directions, tuning to evade deleterious effects on caryopsis physiology and plant performance while only little effect was evident by increasing starch......Starch is of fundamental importance for plant development and reproduction and its optimized molecular assembly is potentially necessary for correct starch metabolism. Re-structuring of starch granules in-planta can therefore potentially affect plant metabolism. Modulation of granule micro...

Starch Granule Re-Structuring by Starch Branching Enzyme and Glucan Water Dikinase Modulation Affects Caryopsis Physiology and Metabolism

DEFF Research Database (Denmark)

Shaik, Shahnoor S.; Obata, Toshihiro; Hebelstrup, Kim H

2016-01-01

Starch is of fundamental importance for plant development and reproduction and its optimized molecular assembly is potentially necessary for correct starch metabolism. Re-structuring of starch granules in-planta can therefore potentially affect plant metabolism. Modulation of granule micro...... in starch granule morphology at maturity. The results demonstrate that decreasing the storage starch branching resulted in metabolic adjustments and re-directions, tuning to evade deleterious effects on caryopsis physiology and plant performance while only little effect was evident by increasing starch...

Starch-templated bio-synthesis of gold nanoflowers for in vitro antimicrobial and anticancer activities

Science.gov (United States)

Borah, D.; Hazarika, M.; Tailor, P.; Silva, A. R.; Chetia, B.; Singaravelu, G.; Das, P.

2018-05-01

We describe an in situ method of synthesizing highly branched gold nanoflower (AuNFs) using aqueous seed extract of Syzygium cumini (L.) Skeels as reductant in the presence of 0.3% starch. Surprisingly, when the same reaction was carried out in the absence of starch or with starch at a lower concentration (0.15%), instead of flower-like morphology quasi-spherical or polyhedral nanoparticles (AuNPs) are obtained. The nanomaterials were extensively characterized by HRTEM, FESEM, UV-Vis, FTIR, XRD, XPS and TGA analysis. The biological activities of the materials were investigated for antimicrobial activities against four bacterial strains that include one Gram positive (Staphylococcus aureus MTCC 121), two Gram negative (Escherichia coli MTCC 40 and Pseudomonas aeruginosa MTCC 4673) and one fungi (Candida albicans MTCC 227). The nanoparticles functioned as effective antimicrobial and anti-biofilm agents against all the strains under study. Controlled study revealed that, the AuNFs showed improved efficacy over conventional polyhedral AuNPs against all the microbes under study which might be attributed to the larger surface-to-volume ratio of the nanoflowers. The AuNFs also showed effective in vitro anticancer activity against a human liver cancer cell line (HepG2) with no significant cytotoxicity. Our data suggest that the AuNFs can significantly reduce the cancer cell growth with IC50 value of 20 µg mL-1.

Powder and compaction characteristics of pregelatinized starches.

Science.gov (United States)

Rojas, J; Uribe, Y; Zuluaga, A

2012-06-01

Pregelatinized starch is widely used as a pharmaceutical aid, especially as a filler-binder. It is known that the tableting performance of excipients could be affected by their source. The aim of this study was to evaluate the powder and tableting properties of pregelatinized starches obtained from yucca, corn and rice and compare those properties with those of Starch 1500. This material had the lowest particle size, and porosity and largest density and best flow. However, yucca starch and corn starch showed an irregular granule morphology, better compactibility and compressibility than Starch 1500. Their onset of plastic deformation and their strain rate sensitivity was comparable to that of Starch 1500. These two materials showed compact disintegration slower that Starch 1500. Conversely, rice starch showed a high elasticity, and friability, low compactibility, which are undesirable for direct compression. This study demonstrated the potential use of pregelatinized starches, especially those obtained from yucca and corn as direct compression filler-binders.

The synthesis conditions, characterizations and thermal degradation studies of an etherified starch from an unconventional source

International Nuclear Information System (INIS)

Lawal, O.S.; Lechner, M.D.; Kulicke, W.M.

2008-05-01

Starch isolated from an under-utilized legume plant (pigeon pea) was carboxymethylated. Influences of reaction parameters were investigated on the degree of substitution (DS) and the reaction efficiency (RE). Studies showed that optimal DS of 1.12 could be reached at reaction efficiency of 80.6 % in isopropanol-water reaction medium (40 deg. C, 3h). The scanning electron microscopy showed that after carboxymethylation, the granular appearance of the native starch was distorted. Wide-angle X-ray diffractometry revealed that crystallinity was reduced significantly after carboxymethylation. The infrared spectra revealed new bands in the carboxymethyl starch at ν =1600, 1426 and 1324 cm -1 and they were attributed to carbonyl functional groups vibration, -CH2 scissoring and OH bending vibration respectively. Broad band 13 C NMR of carboxymethyl starch showed intense peak at δ 180.3 ppm and it was assigned for carbonyl carbon on the carboxymethyl substituent on the AGU (Anhydroglucose Unit). DEPT (Distortionless Enhancement by Polarization Transfer) 135 NMR showed negative signals which correspond to methylene carbons on the AGU. The differential scanning calorimetry (DSC) suggests loss of crystallinity after carboxymethylation. Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and Differential Thermal Analysis (DTA) show that thermal stability improved after carboxymethylation. The study provides information on the preparation and characterization of a biomaterial from a new source which could be used alone or in the preparation of other functional polymers for diverse polymer applications. (author)

Synthesis, characterization, and secondary sludge dewatering performance of a novel combined silicon–aluminum–iron–starch flocculant

Energy Technology Data Exchange (ETDEWEB)

Lin, Qintie, E-mail: qintlin@163.com; Peng, Huanlong; Zhong, Songxiong; Xiang, Jiangxin

2015-03-21

Highlights: • Silicon, aluminum, and iron were grafted onto starch chains to synthesize CSiAFS. • The sludge dewatering performance of CSiAFS was superior to PAC, PAM, and FeCl{sub 3}. • CSiAFS exhibited a good dewatering efficiency over a wide range of pH (3.0–11.0). • CSiAFS had a discontinuous surface with channels which helped to sludge dewatering. - Abstract: Flocculation is one of the most widely used cost-effective pretreatment method for sludge dewatering, and a novel environmentally friendly and efficient flocculant is highly desired in the sludge dewatering field. In this study, a novel combined silicon–aluminum–ferric–starch was synthesized by grafting silicon, aluminum, and iron onto a starch backbone. The synthesized starch flocculant was characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy, X-ray powder diffraction, and thermogravimetric analysis. The dewatering performance of secondary sludge was evaluated according to the capillary suction time, settling volume percentage, and specific resistance to filtration. The results indicated that the copolymer exhibited: (1) a good dewatering efficiency over a wide pH range of 3.0–11.0, (2) superior sludge dewatering performance compared to those of polyaluminum chloride (PACl), polyacrylamide (PAM), ferric chloride, and (3) a discontinuous surface with many channels or voids that helps to mobilize the impermeable thin layer of secondary sludge during filter pressing. Such a novel copolymer is a promising green flocculant for secondary sludge dewatering applications.

Protein targeting to glycogen is a master regulator of glycogen synthesis in astrocytes

KAUST Repository

Ruchti, E.

2016-10-08

The storage and use of glycogen, the main energy reserve in the brain, is a metabolic feature of astrocytes. Glycogen synthesis is regulated by Protein Targeting to Glycogen (PTG), a member of specific glycogen-binding subunits of protein phosphatase-1 (PPP1). It positively regulates glycogen synthesis through de-phosphorylation of both glycogen synthase (activation) and glycogen phosphorylase (inactivation). In cultured astrocytes, PTG mRNA levels were previously shown to be enhanced by the neurotransmitter noradrenaline. To achieve further insight into the role of PTG in the regulation of astrocytic glycogen, its levels of expression were manipulated in primary cultures of mouse cortical astrocytes using adenovirus-mediated overexpression of tagged-PTG or siRNA to downregulate its expression. Infection of astrocytes with adenovirus led to a strong increase in PTG expression and was associated with massive glycogen accumulation (>100 fold), demonstrating that increased PTG expression is sufficient to induce glycogen synthesis and accumulation. In contrast, siRNA-mediated downregulation of PTG resulted in a 2-fold decrease in glycogen levels. Interestingly, PTG downregulation strongly impaired long-term astrocytic glycogen synthesis induced by insulin or noradrenaline. Finally, these effects of PTG downregulation on glycogen metabolism could also be observed in cultured astrocytes isolated from PTG-KO mice. Collectively, these observations point to a major role of PTG in the regulation of glycogen synthesis in astrocytes and indicate that conditions leading to changes in PTG expression will directly impact glycogen levels in this cell type.

Characteristics of cassava starch fermentation wastewater based on structural degradation of starch granules

Directory of Open Access Journals (Sweden)

Juliane Mascarenhas Pereira

2016-01-01

Full Text Available ABSTRACT: Sour cassava starch is a naturally modified starch produced by fermentation and sun drying, achieving the property of expansion upon baking. Sour cassava starch' bakery products can be prepared without the addition of yeast and it is gluten free. The fermentation process associated with this product has been well studied, but the wastewater, with high acidity and richness in other organic compounds derived from starch degradation, requires further investigation. In this study, the structure of solids present in this residue was studied, seeking to future applications for new materials. The solids of the wastewater were spray dried with maltodextrin (MD with dextrose equivalent (DE of 5 and 15 and the structure of the powder was evaluated by scanning electron microscopy. A regular structure with a network arrangement was observed for the dried material with MD of 5 DE, in contrast to the original and fermented starches structure, which suggests a regular organization of this new material, to be studied in future applications.

Cassava starch films containing acetylated starch nanoparticles as reinforcement: Physical and mechanical characterization.

Science.gov (United States)

Teodoro, Ana Paula; Mali, Suzana; Romero, Natália; de Carvalho, Gizilene Maria

2015-08-01

This paper reports the use of acetylated starch nanoparticles (NPAac) as reinforcement in thermoplastic starch films. NPAac with an average size of approximately 500 nm were obtained by nanoprecipitation. Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) indicated that NPAac are more thermally stable and essentially amorphous when compared with acetylated starch. Thermoplastic starch films with different proportions of NPAac (0.5, 1.0, 1.5, 10.0%, w/w) were obtained and characterized by scanning electron microscopy (SEM), water vapor permeability (WVP), adsorption isotherms, TGA and mechanical tests. The inclusion of reinforcement caused changes in film properties: WVP was lowered by 41% for film with 1.5% (w/w) of NPAac and moisture adsorption by 33% for film with 10% (w/w) of NPAac; and the Young's modulus and thermal stability were increased by 162% and 15%, respectively, for film with 0.5% (w/w) of NPAac compared to the starch film without the addition of NPAac. Copyright © 2015 Elsevier Ltd. All rights reserved.

Properties enhancement of cassava starch based bioplastics with addition of graphene oxide

Science.gov (United States)

Amri, A.; Ekawati, L.; Herman, S.; Yenti, S. R.; Zultiniar; Aziz, Y.; Utami, S. P.; Bahruddin

2018-04-01

The properties of cassava starch based bioplastic have been successfully enhanced by additioning of graphene oxide (GO) filler. The composite was synthesized via starch intercalation method using glycerol plasticizer with variation of 5 – 15 % v/v GO filler and mixing time of 30 and 60 minutes. The effects of GO content and the mixing time to the mechanical, water uptake and biodegradation were studied. The synthesis of GO and its integration in the bioplastic composite were also elucidated. The increasing of the GO content and mixing time improved the mechanical properties of composite mainly due to of good homogeneity among the constituents in the composite as indicated by scanning electron microscopy (SEM) and Fourier Transfom Infrared (FTIR) spectroscopy. The bioplastic produced using 15% of GO and 60 minutes mixing time had the highest mechanical properties with tensile strenght of 3,92 Mpa, elongation of 13,22% and modulus young of 29,66 MPa. The water uptake and biodegradation increased as the increase of GO content and decreased as the increase of the mixing time. Graphene oxide is the promissing filler for further development of cassava starch based bioplastics.

Heterologous expression of two Arabidopsis starch dikinases in potato

NARCIS (Netherlands)

Xu, Xuan; Dees, Dianka; Huang, Xing Feng; Visser, Richard G.F.; Trindade, Luisa M.

2018-01-01

Starch phosphate esters influence physiochemical properties of starch granules that are essential both for starch metabolism and industrial use of starches. To modify properties of potato starch and understand the effect of starch phosphorylation on starch metabolism in storage starch, the starch

Reduced starch granule number per chloroplast in the dpe2/phs1 mutant is dependent on initiation of starch degradation.

Science.gov (United States)

Malinova, Irina; Fettke, Joerg

2017-01-01

An Arabidopsis double knock-out mutant lacking cytosolic disproportionating enzyme 2 (DPE2) and the plastidial phosphorylase (PHS1) revealed a dwarf-growth phenotype, reduced starch content, an uneven distribution of starch within the plant rosette, and a reduced number of starch granules per chloroplast under standard growth conditions. In contrast, the wild type contained 5-7 starch granules per chloroplast. Mature and old leaves of the double mutant were essentially starch free and showed plastidial disintegration. Several analyses revealed that the number of starch granules per chloroplast was affected by the dark phase. So far, it was unclear if it was the dark phase per se or starch degradation in the dark that was connected to the observed decrease in the number of starch granules per chloroplast. Therefore, in the background of the double mutant dpe2/phs1, a triple mutant was generated lacking the initial starch degrading enzyme glucan, water dikinase (GWD). The triple mutant showed improved plant growth, a starch-excess phenotype, and a homogeneous starch distribution. Furthermore, the number of starch granules per chloroplast was increased and was similar to wild type. However, starch granule morphology was only slightly affected by the lack of GWD as in the triple mutant and, like in dpe2/phs1, more spherical starch granules were observed. The characterized triple mutant was discussed in the context of the generation of starch granules and the formation of starch granule morphology.

Physicochemical properties of black pepper (Piper nigrum) starch.

Science.gov (United States)

Zhu, Fan; Mojel, Reuben; Li, Guantian

2018-02-01

Black pepper (Piper nigrum) is among the most popular spices around the world. Starch is the major component of black pepper. However, little is known about functional properties of this starch. In this study, swelling, solubility, thermal properties, rheology, and enzyme susceptibility of 2 black pepper starches were studied and compared with those of maize starch. Pepper starch had lower water solubility and swelling power than maize starch. It had higher viscosity during pasting event. In dynamic oscillatory analysis, pepper starch had lower storage modulus. Thermal analysis showed that pepper starch had much higher gelatinization temperatures (e.g., conclusion temperature of 94°C) than maize starch. The susceptibility to α-amylolysis of pepper starch was not very different from that of maize starch. Overall, the differences in the physicochemical properties of the 2 pepper starches are non-significant. The relationships between structure (especially amylopectin internal molecular structure) and properties of starch components are highlighted. Copyright © 2017 Elsevier Ltd. All rights reserved.

Regulation of protein synthesis during sea urchin early development

International Nuclear Information System (INIS)

Kelso, L.C.

1989-01-01

Fertilization of the sea urchin egg results in a 20-40 fold increase in the rate of protein synthesis. The masked message hypothesis proposes that mRNAs are masked or unavailable for translation in the egg. We devised an in vivo assay to test this hypothesis. Our results show that masked mRNAs limit protein synthesis in the unfertilized egg. In addition, we show that protein synthesis is also regulated at the level of translational machinery. Following fertilization is a period of rapid cell divisions. This period, known as the rapid cleavage stage, is characterized by the transient synthesis of a novel set of proteins. The synthesis of these proteins is programmed by maternal mRNAs stored in the unfertilized egg. To study the behavior of these mRNAs, we prepared a cDNA library from polysomal poly (A+) RNA from 2-hour embryos. [ 32 P] labeled probes, prepared from the cDNA library, were used to monitor the levels of individual mRNAs in polysomes at fertilization and during early development

Resistant starch: promise for improving human health.

Science.gov (United States)

Birt, Diane F; Boylston, Terri; Hendrich, Suzanne; Jane, Jay-Lin; Hollis, James; Li, Li; McClelland, John; Moore, Samuel; Phillips, Gregory J; Rowling, Matthew; Schalinske, Kevin; Scott, M Paul; Whitley, Elizabeth M

2013-11-01

Ongoing research to develop digestion-resistant starch for human health promotion integrates the disciplines of starch chemistry, agronomy, analytical chemistry, food science, nutrition, pathology, and microbiology. The objectives of this research include identifying components of starch structure that confer digestion resistance, developing novel plants and starches, and modifying foods to incorporate these starches. Furthermore, recent and ongoing studies address the impact of digestion-resistant starches on the prevention and control of chronic human diseases, including diabetes, colon cancer, and obesity. This review provides a transdisciplinary overview of this field, including a description of types of resistant starches; factors in plants that affect digestion resistance; methods for starch analysis; challenges in developing food products with resistant starches; mammalian intestinal and gut bacterial metabolism; potential effects on gut microbiota; and impacts and mechanisms for the prevention and control of colon cancer, diabetes, and obesity. Although this has been an active area of research and considerable progress has been made, many questions regarding how to best use digestion-resistant starches in human diets for disease prevention must be answered before the full potential of resistant starches can be realized.

Plant-crafted starches for bioplastics production

DEFF Research Database (Denmark)

Sagnelli, Domenico; Hebelstrup, Kim H.; Leroy, Eric

2016-01-01

Transgenically-produced amylose-only (AO) starch was used to manufacture bioplastic prototypes. Extruded starch samples were tested for crystal residues, elasticity, glass transition temperature, mechanical properties, molecular mass and microstructure. The AO starch granule crystallinity was both...... in the storage modulus (E') for AO samples compared to the control. The data support the use of pure starch-based bioplastics devoid of non-polysaccharide fillers....... of the B- and Vh-type, while the isogenic control starch was mainly A-type. The first of three endothermic transitions was attributed to gelatinization at about 60°C. The second and third peaks were identified as melting of the starch and amylose-lipid complexes, respectively. After extrusion, the AO...

Uncoupled regulation of fibronectin and collagen synthesis in Rous sarcoma virus transformed avian tendon cells

International Nuclear Information System (INIS)

Parry, G.; Soo, W.J.; Bissell, M.J.

1979-01-01

The regulation of fibronectin and procollagen synthesis has been investigated in normal and Rous sarcoma virus transformed primary avian tendon cells. These two proteins interact at the cell periphery and both are reportedly lost upon transformation. Whether their synthesis was coordinately regulated in Rous sarcoma virus-infected cells was thus examined. It was found that while the synthesis of both pro α 1 and pro α 2 peptides was reduced upon transformation, the synthesis of fibronectin was not altered. Nevertheless, long term radiolabeling demonstrated that fibronectin levels were reduced in transformed cells. It is concluded that the reduction in levels of these components at the surface is brought about by different mechanisms; collagen levels being regulated by procollagen synthesis and fibronectin levels by degradation and/or release into the culture medium. The possibility is discussed that fibronectin is lost from the cell periphery of primary avian tendon cells as a consequence of decreased levels of anchoring collagen molecules

Protein targeting to glycogen is a master regulator of glycogen synthesis in astrocytes

OpenAIRE

E. Ruchti; P.J. Roach; A.A. DePaoli-Roach; P.J. Magistretti; I. Allaman

2016-01-01

The storage and use of glycogen, the main energy reserve in the brain, is a metabolic feature of astrocytes. Glycogen synthesis is regulated by Protein Targeting to Glycogen (PTG), a member of specific glycogen-binding subunits of protein phosphatase-1 (PPP1). It positively regulates glycogen synthesis through de-phosphorylation of both glycogen synthase (activation) and glycogen phosphorylase (inactivation). In cultured astrocytes, PTG mRNA levels were previously shown to be enhanced by the ...

Analysis of Biodegradation of Bioplastics Made of Cassava Starch

Directory of Open Access Journals (Sweden)

Nanang Eko Wahyuningtiyas

2017-08-01

Full Text Available Environmental pollution due to plastic waste taking too long to decompose has become a global problem. There have been numerous solutions proposed, one of which is the use of bioplastics. The use of cassava starch as the main ingredient in the manufacture of bioplastics shows great potential, since Indonesia has a diverse range of starch-producing plants. The aim of the present study is to analyse the effect of glycerol on microbial degradation. This experimental research investigated the use of cassava flour mixed with glycerol plasticizer at various concentrations (0, 2, 2.5, 3% in the synthesis of bioplastics. The aspects studied were biodegradability, moisture absorption (using ASTM D570, shelf life, and morphological properties (using a camera equipped with a macro lens and SEM. This study revealed that complete degradation could be achieved on the 9th day. The addition of a large concentration of glycerol would accelerate the microbial degradation process, increase moisture, and extend the shelf life of bioplastics in a dry place.

Characterisation of hydroxypropylated crosslinked sago starch as compared to commercial modified starches

Directory of Open Access Journals (Sweden)

Saowakon Wattanachant

2002-07-01

Full Text Available The characteristics of hydroxypropylated crosslinked sago starch (HPST were determined and compared with five types of commercial modified starches (CMST in order to evaluate its quality for further applications. The HPST was prepared on a large scale having molar substitution (MS and degree substitution (DS values in the range of 0.038 to 0.045 and 0.004 to 0.005, respectively. The properties of HPST in terms of sediment volume, swelling power, solubility and paste clarity were 15.75%, 16.7, 8.62% and 5.18%T650 , respectively. The MS value, phosphorus content, paste clarity, swelling power and syneresis after six freeze-thaw cycles of HPST when compared to that of commercially available modified starches which are normally used or incorporated in acidic, frozen and canned foods did not differ significantly. The pasting characteristic of HPST exhibited thin to thick viscosity which was similar (P>0.05 to that of commercial hydroxypropylated crosslinked tapioca starch (NAT 8. The acid stability, solubility and freeze-thaw stability of both starches were also similar (P>0.05 but the swelling power of HPST was slightly lower (P<0.05 than that of NAT 8 .

Comparative Phosphoproteomic Analysis of the Developing Seeds in Two Indica Rice ( Oryza sativa L.) Cultivars with Different Starch Quality.

Science.gov (United States)

Pang, Yuehan; Zhou, Xin; Chen, Yaling; Bao, Jinsong

2018-03-21

Protein phosphorylation plays important roles in regulation of various molecular events such as plant growth and seed development. However, its involvement in starch biosynthesis is less understood. Here, a comparative phosphoproteomic analysis of two indica rice cultivars during grain development was performed. A total of 2079 and 2434 phosphopeptides from 1273 and 1442 phosphoproteins were identified, covering 2441 and 2808 phosphosites in indica rice 9311 and Guangluai4 (GLA4), respectively. Comparative analysis identified 303 differentially phosphorylated peptides, and 120 and 258 specifically phosphorylated peptides in 9311 and GLA4, respectively. Phosphopeptides in starch biosynthesis related enzymes such as AGPase, SSIIa, SSIIIa, BEI, BEIIb, PUL, and Pho1were identified. GLA4 and 9311 had different amylose content, pasting viscosities, and gelatinization temperature, suggesting subtle difference in starch biosynthesis and regulation between GLA4 and 9311. Our study will give added impetus to further understanding the regulatory mechanism of starch biosynthesis at the phosphorylation level.

Effects of starch synthase IIa gene dosage on grain, protein and starch in endosperm of wheat.

Science.gov (United States)

Konik-Rose, Christine; Thistleton, Jenny; Chanvrier, Helene; Tan, Ihwa; Halley, Peter; Gidley, Michael; Kosar-Hashemi, Behjat; Wang, Hong; Larroque, Oscar; Ikea, Joseph; McMaugh, Steve; Regina, Ahmed; Rahman, Sadequr; Morell, Matthew; Li, Zhongyi

2007-11-01

Starch synthases (SS) are responsible for elongating the alpha-1,4 glucan chains of starch. A doubled haploid population was generated by crossing a line of wheat, which lacks functional ssIIa genes on each genome (abd), and an Australian wheat cultivar, Sunco, with wild type ssIIa alleles on each genome (ABD). Evidence has been presented previously indicating that the SGP-1 (starch granule protein-1) proteins present in the starch granule in wheat are products of the ssIIa genes. Analysis of 100 progeny lines demonstrated co-segregation of the ssIIa alleles from the three genomes with the SGP-1 proteins, providing further evidence that the SGP-1 proteins are the products of the ssIIa genes. From the progeny lines, 40 doubled haploid lines representing the eight possible genotypes for SSIIa (ABD, aBD, AbD, ABd, abD, aBd, Abd, abd) were characterized for their grain weight, protein content, total starch content and starch properties. For some properties (chain length distribution, pasting properties, swelling power, and gelatinization properties), a progressive change was observed across the four classes of genotypes (wild type, single nulls, double nulls and triple nulls). However, for other grain properties (seed weight and protein content) and starch properties (total starch content, granule morphology and crystallinity, granule size distribution, amylose content, amylose-lipid dissociation properties), a statistically significant change only occurred for the triple nulls, indicating that all three genes had to be missing or inactive for a change to occur. These results illustrate the importance of SSIIa in controlling grain and starch properties and the importance of amylopectin fine structure in controlling starch granule properties in wheat.

Acetylation and characterization of banana (Musa paradisiaca) starch.

Science.gov (United States)

Bello-Pérez, L A; Contreras-Ramos, S M; Jìmenez-Aparicio, A; Paredes-López, O

2000-01-01

Banana native starch was acetylated and some of its functional properties were evaluated and compared to corn starch. In general, acetylated banana starch presented higher values in ash, protein and fat than corn acetylated starch. The modified starches had minor tendency to retrogradation assessed as % transmittance of starch pastes. At high temperature acetylated starches presented a water retention capacity similar to their native counterpart. The acetylation considerably increased the solubility of starches, and a similar behavior was found for swelling power. When freeze-thaw stability was studied, acetyl banana starch drained approximately 60% of water in the first and second cycles, but in the third and fourth cycles the percentage of separated water was low. However, acetyl corn starch showed lower freeze-thaw stability than the untreated sample. The modification increased the viscosity of banana starch pastes.

Sixth taste – starch taste?

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Zygmunt Zdrojewicz

2017-06-01

Full Text Available Scientists from Oregon State University, USA, came up with the newest theory of the sixth taste – starch taste that might soon join the basic five tastes. This argument is supported by studies done on both animals and humans, the results of which seem to indicate the existence of separate receptors for starch taste, others than for sweet taste. Starch is a glucose homopolymer that forms an α-glucoside chain called glucosan or glucan. This polysaccharide constitutes the most important source of carbohydrates in food. It can be found in groats, potatoes, legumes, grains, manioc and corn. Apart from its presence in food, starch is also used in textile, pharmaceutical, cosmetic and stationery industries as well as in glue production. This polysaccharide is made of an unbranched helical structure – amylose (15–20%, and a structure that forms branched chains – amylopectin (80–85%. The starch structure, degree of its crystallisation or hydration as well as its availability determine the speed of food-contained starch hydrolysis by amylase. So far, starch has been considered tasteless, but the newest report shows that for people of different origins it is associated with various aliments specific for each culture. Apart from a number of scientific experiments using sweet taste inhibitors, the existence of the sixth taste is also confirmed by molecular studies. However, in order to officially include starch taste to the basic human tastes, it must fulfil certain criteria. The aim of the study is to present contemporary views on starch.

Preparation and characterization of dialdehyde starch urea (DASU ...

African Journals Online (AJOL)

Dialdehyde starch urea (DASU) was prepared by the reaction of dialdehyde starch (DAS) from periodate oxidized cassava starch with urea, which was then used to adsorb Co(II), Pb(II) and Zn(II) ions from aqueous solution. Starch modified starches and starch complexes were characterized by Fourier transform infrared ...

Rice starch granule amylolysis--differentiating effects of particle size, morphology, thermal properties and crystalline polymorph.

Science.gov (United States)

Dhital, Sushil; Butardo, Vito M; Jobling, Stephen A; Gidley, Michael J

2015-01-22

The underlying mechanism of amylolysis of rice starch granules was investigated using isolated starch granules from wild-type, as well as SBEIIb mutant and down-regulated lines. Fused granule agglomerates isolated from mutant and transgenic lines were hydrolysed at similar rates by amylases, and had similar crystalline patterns and thermal properties as individual granules. Surface pores, a feature previously only reported for A-polymorphic starch granules, were also observed in B- and C-polymorphic rice starch granules. Although the microscopic patterns of hydrolysis among granules with different crystalline polymorphs were qualitatively similar, the extent and the rate of amylolysis were different, suggesting that B-type crystalline polymorphs are intrinsically more resistant to enzymatic hydrolysis than A-type in rice starch granules. It is proposed that the slightly longer branch lengths of amylopectin which leads to the formation of more stable B-type double helical structures compared to their A-type counterparts is the major parameter, with other factors such as granule size, surface pores and interior channels having secondary roles, in determining the rate of enzymatic hydrolysis of rice starch granules. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enzymatic modification of starch

DEFF Research Database (Denmark)

Jensen, Susanne Langgård

In the food industry approaches for using bioengineering are investigated as alternatives to conventional chemical and physical starch modification techniques in development of starches with specific properties. Enzyme-assisted post-harvest modification is an interesting approach to this, since...... it is considered a clean and energy saving technology. This thesis aimed to investigate the effect of using reaction conditions, simulating an industrial process, for enzymatic treatment of starch with branching enzyme (BE) from Rhodothermus obamensis. Thus treatements were conducted at 70°C using very high...... substrate concentration (30-40% dry matter (DM)) and high enzyme activity (750-2250 BE units (BEU)/g sample). Starches from various botanical sources, representing a broad range of properties, were used as substrates. The effects of the used conditions on the BE-reaction were evaluated by characterization...

Starch and starch hydrolysates are favorable carbon sources for bifidobacteria in the human gut.

Science.gov (United States)

Liu, Songling; Ren, Fazheng; Zhao, Liang; Jiang, Lu; Hao, Yanling; Jin, Junhua; Zhang, Ming; Guo, Huiyuan; Lei, Xingen; Sun, Erna; Liu, Hongna

2015-03-01

Bifidobacteria are key commensals in human gut, and their abundance is associated with the health of their hosts. Although they are dominant in infant gut, their number becomes lower in adult gut. The changes of the diet are considered to be main reason for this difference. Large amounts of whole-genomic sequence data of bifidobacteria make it possible to elucidate the genetic interpretation of their adaptation to the nutrient environment. Among the nutrients in human gut, starch is a highly fermentable substrate and can exert beneficial effects by increasing bifidobacteria and/or being fermented to short chain fatty acids. In order to determine the potential substrate preference of bifidobacteria, we compared the glycoside hydrolase (GH) profiles of a pooled-bifidobacterial genome (PBG) with a representative microbiome (RM) of the human gut. In bifidobacterial genomes, only 15% of GHs contained signal peptides, suggesting their weakness in utilization of complex carbohydrate, such as plant cell wall polysaccharides. However, compared with other intestinal bacteria, bifidobacteiral genomes encoded more GH genes for degrading starch and starch hydrolysates, indicating that they have genetic advantages in utilizing these substrates. Bifidobacterium longum subsp. longum BBMN68 isolated from centenarian's faeces was used as a model strain to further investigate the carbohydrate utilization. The pathway for degrading starch and starch hydrolysates was the only complete pathway for complex carbohydrates in human gut. It is noteworthy that all of the GH genes for degrading starch and starch hydrolysates in the BBMN68 genome were conserved in all studied bifidobacterial strains. The in silico analyses of BBMN68 were further confirmed by growth experiments, proteomic and real-time quantitative PCR (RT-PCR) analyses. Our results demonstrated that starch and starch hydrolysates were the most universal and favorable carbon sources for bifidobacteria. The low amount of these

Members of the LBD family of transcription factors repress anthocyanin synthesis and affect additional nitrogen responses in Arabidopsis.

Science.gov (United States)

Rubin, Grit; Tohge, Takayuki; Matsuda, Fumio; Saito, Kazuki; Scheible, Wolf-Rüdiger

2009-11-01

Nitrogen (N) and nitrate (NO(3)(-)) per se regulate many aspects of plant metabolism, growth, and development. N/NO(3)(-) also suppresses parts of secondary metabolism, including anthocyanin synthesis. Molecular components for this repression are unknown. We report that three N/NO(3)(-)-induced members of the LATERAL ORGAN BOUNDARY DOMAIN (LBD) gene family of transcription factors (LBD37, LBD38, and LBD39) act as negative regulators of anthocyanin biosynthesis in Arabidopsis thaliana. Overexpression of each of the three genes in the absence of N/NO(3)(-) strongly suppresses the key regulators of anthocyanin synthesis PAP1 and PAP2, genes in the anthocyanin-specific part of flavonoid synthesis, as well as cyanidin- but not quercetin- or kaempferol-glycoside production. Conversely, lbd37, lbd38, or lbd39 mutants accumulate anthocyanins when grown in N/NO(3)(-)-sufficient conditions and show constitutive expression of anthocyanin biosynthetic genes. The LBD genes also repress many other known N-responsive genes, including key genes required for NO(3)(-) uptake and assimilation, resulting in altered NO(3)(-) content, nitrate reductase activity/activation, protein, amino acid, and starch levels, and N-related growth phenotypes. The results identify LBD37 and its two close homologs as novel repressors of anthocyanin biosynthesis and N availability signals in general. They also show that, besides being developmental regulators, LBD genes fulfill roles in metabolic regulation.

Functional Characterization of the Canine Heme-Regulated eIF2α Kinase: Regulation of Protein Synthesis

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Kimon C. Kanelakis

2009-01-01

Full Text Available The heme-regulated inhibitor (HRI negatively regulates protein synthesis by phosphorylating eukaryotic initiation factor-2α (eIF2α thereby inhibiting protein translation. The importance of HRI in regulating hemoglobin synthesis in erythroid cells makes it an attractive molecular target in need of further characterization. In this work, we have cloned and expressed the canine form of the HRI kinase. The canine nucleotide sequence has 86%, 82%, and 81% identity to the human, mouse, and rat HRI, respectively. It was noted that an isoleucine residue in the ATP binding site of human, rat, and mouse HRI is replaced by a valine in the canine kinase. The expression of canine HRI protein by in vitro translation using wheat germ lysate or in Sf9 cells using a baculovirus expression system was increased by the addition of hemin. Following purification, the canine protein was found to be 72 kD and showed kinase activity determined by its ability to phosphorylate a synthetic peptide substrate. Quercetin, a kinase inhibitor known to inhibit mouse and human HRI, inhibits canine HRI in a concentration-dependent manner. Additionally, quercetin is able to increase de novo protein synthesis in canine reticulocytes. We conclude that the canine is a suitable model species for studying the role of HRI in erythropoiesis.

Effects of water on starch-g-polystyrene and starch-g-poly(methyl acrylate) extrudates

International Nuclear Information System (INIS)

Henderson, A.M.; Rudin, A.

1982-01-01

Polystyrene and poly(methyl acrylate) were grafted onto wheat starch by gamma radiation and chemical initiation, respectively. The respective percent add-on values were 46 and 45; 68% of the polystyrene formed was grafted to starch, and corresponding proportion of poly(methyl acrylate) was 41%. The molecular weight distributions of the homopolymer and graft portions were characterized, and extrusion conditions were established for production of ribbon samples of starch-g-PS and starch-g-PMA. Both copolymer types were considerably weakened by soaking in water, and this effect was more immediate and drastic for starch-g-poly(methyl acrylate). Both graft copolymers regained their original tensile strengths on drying, but the poly(methyl acrylate) specimens did not recover their original unswollen dimensions and retained high breaking elongations characteristic of soaked specimens. Tensile and dynamic mechanical properties of extruded and molded samples of both graft polymers are reported, and plasticizing effects of water are summarized

Modification of rice starch by gamma irradiation to produce soluble starch of low viscosity for industrial purposes

International Nuclear Information System (INIS)

El Saadany, R.M.A.; El Saadany, F.M.; Foda, Y.H.

1974-01-01

Because starch of low viscosity is important for industrial purposes this research was carried out to study the possibility of producing this sort of starch by treating rice starch with γ-irradiation. Results indicated than when rice starch was modified by γ-irradiation, the reducing power increased and degradation as well as molecular breakdown occured followed by sharp decrease of its viscosity, specific viscosity and intrisinc viscosity. Results showed that starch became more soluble by treating with γ-irradiation and lost its resistance to water as its swelling capacity decreased. All these changes were proportional to the doses of γ-irradiation. (orig.) [de

Do rice suspension-cultured cells treated with abscisic acid mimic developing seeds?

Science.gov (United States)

Matsuno, Koya; Fujimura, Tatsuhito

2015-08-01

Starch synthesis is activated in the endosperm during seed development and also in rice suspension cells cultured with abscisic acid. In the anticipation that the mechanisms of starch synthesis are similar between the endosperm and the suspension cells cultured with abscisic acid, expression of genes involved in starch synthesis was evaluated in the suspension cells after abscisic acid treatment. However, it was found that the regulatory mechanism of starch synthesis in the suspension cells cultured with abscisic acid was different from that in developing seeds. Expression analyses of genes involved in oil bodies, which accumulate in the embryo and aleurone layer, and seed storage proteins, which accumulate mainly in the endosperm, showed that the former were activated in the suspension cells cultured with abscisic acid, but the latter were not. Master regulators for embryogenesis, OsVP1 (homologue of AtABI3) and OsLFL1 (homologue of AtFUS3 or AtLFL2), were expressed in the suspension cells at levels comparable to those in the embryo. From these results, it is suggested that interactions between regulators and abscisic acid control the synthesis of phytic acid and oil bodies in the cultured cells and embryo. We suggest that the system of suspension cells cultured with abscisic acid helps to reveal the mechanisms of phytic acid and oil body synthesis in embryo.

Preparation, characterization and utilization of starch nanoparticles.

Science.gov (United States)

Kim, Hee-Young; Park, Sung Soo; Lim, Seung-Taik

2015-02-01

Starch is one of the most abundant biopolymers in nature and is typically isolated from plants in the form of micro-scale granules. Recent studies reported that nano-scale starch particles could be readily prepared from starch granules, which have unique physical properties. Because starch is environmentally friendly, starch nanoparticles are suggested as one of the promising biomaterials for novel utilization in foods, cosmetics, medicines as well as various composites. An overview of the most up-to-date information regarding the starch nanoparticles including the preparation processes and physicochemical characterization will be presented in this review. Additionally, the prospects and outlooks for the industrial utilization of starch nanoparticles will be discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Cassava starch in the Brazilian food industry

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Ivo Mottin Demiate

2011-06-01

Full Text Available Cassava starch is a valued raw material for producing many kinds of modified starches for food applications. Its physicochemical properties, as well as its availability, have made it an interesting and challenging ingredient for the food industry. In the present work, food grade modified cassava starches were purchased from producers and analyzed for selected physicochemical characteristics. Samples of sour cassava starch were included, as well as one sample of native cassava starch. Results showed that almost all modified starches were resistant to syneresis, produced pastes more stable to stirred cooking, and some of them were difficult to cook. The sour cassava starches presented high acidity and resulted in clear and unstable pastes during stirred cooking, susceptible to syneresis.

Physicochemical Properties of Gamma-Irradiated Corn Starch

International Nuclear Information System (INIS)

Lee, Y.J.; Lim, S.T.; Kim, S.Y.; Han, S.M.; Kim, H.M.; Kang, I.J.

2006-01-01

Structural modification of corn starch by gamma irradiation was evaluated for under dry conditions at varied intensities from 0 to 40 kGy. Under scanning electron microscopy, the granule shape of corn starch was not significantly affected by the irradiation up to 40 kGy. In addition, X-ray diffraction and melting patterns of the irradiated starches were similar to those of the native starch, indicating that crystalline regions in the starch granules were not changed by irradiation. However, the pattern of gel permeation column chromatography showed a significant increase in partial hydrolysis of gamma irradiated starch samples

Plant-crafted starches for bioplastics production.

Science.gov (United States)

Sagnelli, Domenico; Hebelstrup, Kim H; Leroy, Eric; Rolland-Sabaté, Agnès; Guilois, Sophie; Kirkensgaard, Jacob J K; Mortensen, Kell; Lourdin, Denis; Blennow, Andreas

2016-11-05

Transgenically-produced amylose-only (AO) starch was used to manufacture bioplastic prototypes. Extruded starch samples were tested for crystal residues, elasticity, glass transition temperature, mechanical properties, molecular mass and microstructure. The AO starch granule crystallinity was both of the B- and Vh-type, while the isogenic control starch was mainly A-type. The first of three endothermic transitions was attributed to gelatinization at about 60°C. The second and third peaks were identified as melting of the starch and amylose-lipid complexes, respectively. After extrusion, the AO samples displayed Vh- and B-type crystalline structures, the B-type polymorph being the dominant one. The AO prototypes demonstrated a 6-fold higher mechanical stress at break and 2.5-fold higher strain at break compared to control starch. Dynamic mechanical analysis showed a significant increase in the storage modulus (E') for AO samples compared to the control. The data support the use of pure starch-based bioplastics devoid of non-polysaccharide fillers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Green starch conversions : Studies on starch acetylation in densified CO2

NARCIS (Netherlands)

Muljana, Henky; Picchioni, Francesco; Heeres, Hero J.; Janssen, Leon P. B. M.

2010-01-01

The acetylation of potato starch with acetic anhydride (AAH) and sodium acetate (NaOAc) as catalyst in densified CO2 was explored in a batch reactor setup. The effects of process variables such as pressure (6-9.8 MPa), temperature (40-90 degrees C), AAH to starch ratio (2-5 mol/mol AGU), NaOAc to

Starch Characteristics Linked to Gluten-Free Products

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Stefan W. Horstmann

2017-04-01

Full Text Available The increasing prevalence of coeliac disease (CD and gluten-related disorders has led to increasing consumer demand for gluten-free products with quality characteristics similar to wheat bread. The replacement of gluten in cereal-based products remains a challenge for scientists, due to its unique role in network formation, which entraps air bubbles. When gluten is removed from a flour, starch is the main component left. Starch is used as gelling, thickening, adhesion, moisture-retention, stabilizing, film forming, texturizing and anti-staling ingredient. The extent of these properties varies depending on the starch source. The starches can additionally be modified increasing or decreasing certain properties of the starch, depending on the application. Starch plays an important role in the formulation of bakery products and has an even more important role in gluten-free products. In gluten-free products, starch is incorporated into the food formulation to improve baking characteristics such as the specific volume, colour and crumb structure and texture. This review covers a number of topics relating to starch; including; an overview of common and lesser researched starches; chemical composition; morphology; digestibility; functionality and methods of modification. The emphasis of this review is on starch and its properties with respect to the quality of gluten-free products.

Starch Characteristics Linked to Gluten-Free Products.

Science.gov (United States)

Horstmann, Stefan W; Lynch, Kieran M; Arendt, Elke K

2017-04-06

The increasing prevalence of coeliac disease (CD) and gluten-related disorders has led to increasing consumer demand for gluten-free products with quality characteristics similar to wheat bread. The replacement of gluten in cereal-based products remains a challenge for scientists, due to its unique role in network formation, which entraps air bubbles. When gluten is removed from a flour, starch is the main component left. Starch is used as gelling, thickening, adhesion, moisture-retention, stabilizing, film forming, texturizing and anti-staling ingredient. The extent of these properties varies depending on the starch source. The starches can additionally be modified increasing or decreasing certain properties of the starch, depending on the application. Starch plays an important role in the formulation of bakery products and has an even more important role in gluten-free products. In gluten-free products, starch is incorporated into the food formulation to improve baking characteristics such as the specific volume, colour and crumb structure and texture. This review covers a number of topics relating to starch; including; an overview of common and lesser researched starches; chemical composition; morphology; digestibility; functionality and methods of modification. The emphasis of this review is on starch and its properties with respect to the quality of gluten-free products.

Biological synthesis of Au nanoparticles using liquefied mash of cassava starch and their functionalization for enhanced hydrolysis of xylan by recombinant xylanase.

Science.gov (United States)

Zeng, Sumei; Du, Liangwei; Huang, Meiying; Feng, Jia-Xun

2016-05-01

Au nanoparticles (AuNPs) have shown the potential for a variety of applications due to their unique physical and chemical properties. In this study, a facile and affordable method for the synthesis of AuNPs via the liquefied mash of cassava starch has been described and the functionalized AuNPs by L-cysteine improved activity of recombinant xylanase was demonstrated. UV-Vis absorption spectroscopy, transmission electron microscopy, and zeta potential measurements were performed to characterize the AuNPs and monitor their synthesis. The presence of Au was confirmed by energy-dispersive X-ray spectroscopy (EDX) and the X-ray diffraction patterns showed that Au nanocrystals were face-centered cubic. The C=O stretching vibration in the Fourier transform infrared spectrum of AuNPs suggested that the hemiacetal C-OH of sugar molecules performed the reduction of Au³⁺ to Au⁰. The presence of C and O in the EDX spectrum and the negative zeta potential of AuNPs suggested that the biomolecules present in liquefied cassava mash were responsible for the stabilization of AuNPs. The surface of AuNPs was easily functionalized by L-cysteine, which improved the stability of AuNPs. Moreover, cysteine-functionalized AuNPs could significantly improve recombinant xylanase efficiency and stability.

Genetic regulation of phenazine-1-carboxamide synthesis by Pseudomonas chlororaphis strain PCL1391

NARCIS (Netherlands)

Girard, Genevieve

2006-01-01

A general overview of regulation of secondary metabolism in Pseudomonas species is given in Chapter 1. Several approaches were combined to identify novel genes involved in the regulation of PCN synthesis and to study their interactions with other regulators. Site-directed mutagenesis was used to

Rheological and microstructural properties of Irradiated starch

International Nuclear Information System (INIS)

Atrous Turki, Hager

2011-01-01

Gamma irradiation ia s fast and efficient method to improve the functional properties of straches. Wheat and potato starches were submitted, in the present study, at 3,5,10 and 20 kGy radiation dose. The changes induced by irradiation on the rheological properties of these starches showed a decrease in the viscosity with increasing radiation dose. Chemicals bond's hydrolysis has been induced by free radicals that have been identified by EPR. Wheat starch presents five EPR signals after irradiation, whiles potato starch has a weak EPR signal. On the other hand, irradiation caused decrease in amylose content. This decrease is more pronounced in potato starch. Dry irradiated starch's MEB revealed no change in the shape, size and distribution of the granules. While, the observation of wheat starch allowed the complete disappearance of the granular structure and the dissolution of its macromolecules after irradiation which justifies the significant decrease in wheat starch's viscosity irradiated at 20 kGy.

ENZYME RESISTANCE OF GENETICALLY MODIFIED STARCH POTATOES

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A. Sh. Mannapova

2015-01-01

Full Text Available Here in this article the justification of expediency of enzyme resistant starch use in therapeutic food products is presented . Enzyme resistant starch is capable to resist to enzymatic hydrolysis in a small intestine of a person, has a low glycemic index, leads to decrease of postprandial concentration of glucose, cholesterol, triglycerides in blood and insulin reaction, to improvement of sensitivity of all organism to insulin, to increase in sense of fulness and to reduction of adjournment of fats. Resistant starch makes bifidogenшс impact on microflora of a intestine of the person, leads to increase of a quantity of lactobacillus and bifidobacterium and to increased production of butyric acid in a large intestine. In this regard the enzyme resistant starch is an important component in food for prevention and curing of human diseases such as diabetes, obesity, colitis, a cancer of large and direct intestine. One method is specified by authors for imitation of starch digestion in a human body. This method is based on the definition of an enzyme resistance of starch in vitro by its hydrolysis to glucose with application of a glucoamylase and digestive enzyme preparation Pancreatin. This method is used in researches of an enzyme resistance of starch, of genetically modified potato, high amylose corn starch Hi-Maize 1043 and HYLON VII (National Starch Food Innovation, USA, amylopectin and amylose. It is shown that the enzyme resistance of the starch emitted from genetically modified potatoes conforms to the enzyme resistance of the high amylose corn starch “Hi-Maize 1043 and HYLON VII starch”, (National Starch Food Innovation, the USA relating to the II type of enzyme resistant starch. It is established that amylopectin doesn't have the enzyme resistant properties. The results of researches are presented. They allow us to make the following conclusion: amylose in comparison with amylopectin possesses higher enzyme resistance and gives to

Engineering Potato Starch with a Higher Phosphate Content.

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Xuan Xu

Full Text Available Phosphate esters are responsible for valuable and unique functionalities of starch for industrial applications. Also in the cell phosphate esters play a role in starch metabolism, which so far has not been well characterized in storage starch. Laforin, a human enzyme composed of a carbohydrate-binding module and a dual-specificity phosphatase domain, is involved in the dephosphorylation of glycogen. To modify phosphate content and better understand starch (dephosphorylation in storage starch, laforin was engineered and introduced into potato (cultivar Kardal. Interestingly, expression of an (engineered laforin in potato resulted in significantly higher phosphate content of starch, and this result was confirmed in amylose-free potato genetic background (amf. Modified starches exhibited altered granule morphology and size compared to the control. About 20-30% of the transgenic lines of each series showed red-staining granules upon incubation with iodine, and contained higher phosphate content than the blue-stained starch granules. Moreover, low amylose content and altered gelatinization properties were observed in these red-stained starches. Principle component and correlation analysis disclosed a complex correlation between starch composition and starch physico-chemical properties. Ultimately, the expression level of endogenous genes involved in starch metabolism was analysed, revealing a compensatory response to the decrease of phosphate content in potato starch. This study provides a new perspective for engineering starch phosphate content in planta by making use of the compensatory mechanism in the plant itself.

Lewis lung carcinoma regulation of mechanical stretch-induced protein synthesis in cultured myotubes.

Science.gov (United States)

Gao, Song; Carson, James A

2016-01-01

Mechanical stretch can activate muscle and myotube protein synthesis through mammalian target of rapamycin complex 1 (mTORC1) signaling. While it has been established that tumor-derived cachectic factors can induce myotube wasting, the effect of this catabolic environment on myotube mechanical signaling has not been determined. We investigated whether media containing cachectic factors derived from Lewis lung carcinoma (LLC) can regulate the stretch induction of myotube protein synthesis. C2C12 myotubes preincubated in control or LLC-derived media were chronically stretched. Protein synthesis regulation by anabolic and catabolic signaling was then examined. In the control condition, stretch increased mTORC1 activity and protein synthesis. The LLC treatment decreased basal mTORC1 activity and protein synthesis and attenuated the stretch induction of protein synthesis. LLC media increased STAT3 and AMP-activated protein kinase phosphorylation in myotubes, independent of stretch. Both stretch and LLC independently increased ERK1/2, p38, and NF-κB phosphorylation. In LLC-treated myotubes, the inhibition of ERK1/2 and p38 rescued the stretch induction of protein synthesis. Interestingly, either leukemia inhibitory factor or glycoprotein 130 antibody administration caused further inhibition of mTORC1 signaling and protein synthesis in stretched myotubes. AMP-activated protein kinase inhibition increased basal mTORC1 signaling activity and protein synthesis in LLC-treated myotubes, but did not restore the stretch induction of protein synthesis. These results demonstrate that LLC-derived cachectic factors can dissociate stretch-induced signaling from protein synthesis through ERK1/2 and p38 signaling, and that glycoprotein 130 signaling is associated with the basal stretch response in myotubes. Copyright © 2016 the American Physiological Society.

Kinetic modelling of enzymatic starch hydrolysis

NARCIS (Netherlands)

Bednarska, K.A.

2015-01-01

Kinetic modelling of enzymatic starch hydrolysis – a summary

K.A. Bednarska

The dissertation entitled ‘Kinetic modelling of enzymatic starch hydrolysis’ describes the enzymatic hydrolysis and kinetic modelling of liquefaction and saccharification of wheat starch.

VCP and ATL1 regulate endoplasmic reticulum and protein synthesis for dendritic spine formation.

Science.gov (United States)

Shih, Yu-Tzu; Hsueh, Yi-Ping

2016-03-17

Imbalanced protein homeostasis, such as excessive protein synthesis and protein aggregation, is a pathogenic hallmark of a range of neurological disorders. Here, using expression of mutant proteins, a knockdown approach and disease mutation knockin mice, we show that VCP (valosin-containing protein), together with its cofactor P47 and the endoplasmic reticulum (ER) morphology regulator ATL1 (Atlastin-1), regulates tubular ER formation and influences the efficiency of protein synthesis to control dendritic spine formation in neurons. Strengthening the significance of protein synthesis in dendritic spinogenesis, the translation blocker cyclohexamide and the mTOR inhibitor rapamycin reduce dendritic spine density, while a leucine supplement that increases protein synthesis ameliorates the dendritic spine defects caused by Vcp and Atl1 deficiencies. Because VCP and ATL1 are the causative genes of several neurodegenerative and neurodevelopmental disorders, we suggest that impaired ER formation and inefficient protein synthesis are significant in the pathogenesis of multiple neurological disorders.

A REVIEW ON BIODEGRADABLE STARCH BASED FILM

Directory of Open Access Journals (Sweden)

Hooman Molavi

2015-04-01

Full Text Available In recent years, biodegradable edible films have become very important in research related to food, due to their compatibility with the environment and their use in the food packaging industry. Various sources can be used in the production of biopolymers as biodegradable films that include polysaccharides, proteins and lipids. Among the various polysaccharides, starch due to its low price and its abundance in nature is of significant importance. Several factors affect the properties of starch films; such as the source which starch is obtained from, as well as the ratio of constituents of the starch. Starch films have advantages such as low thickness, flexibility and transparency though; there are some downsides to mention, such as the poor mechanical properties and water vapor permeability. Thus, using starch alone to produce the film will led to restrictions on its use. To improve the mechanical properties of starch films and also increases resistance against humidity, several methods can be used; including the starch modifying techniques such as cross linking of starch and combining starch with other natural polymers. Other methods such as the use of lipid in formulations of films to increase the resistance to moisture are possible, but lipids are susceptible to oxidation. Therefore, new approaches are based on the integration of different biopolymers in food packaging.

DMPD: Regulation of nitric oxide synthesis and apoptosis by arginase and argininerecycling. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 17513437 Regulation of nitric oxide synthesis and apoptosis by arginase and arginin...tion of nitric oxide synthesis and apoptosis by arginase and argininerecycling. A...erecycling. Mori M. J Nutr. 2007 Jun;137(6 Suppl 2):1616S-1620S. (.png) (.svg) (.html) (.csml) Show Regulation of nitric oxide synthe...sis and apoptosis by arginase and argininerecycling. PubmedID 17513437 Title Regula

Comparison of starch granule development and physicochemical properties of starches in wheat pericarp and endosperm.

Science.gov (United States)

Yu, Xurun; Zhou, Liang; Zhang, Jing; Yu, Heng; Xiong, Fei; Wang, Zhong

2015-01-01

The objectives of this study were: (i) to characterize structural development of starch granule in pericarp and endosperm during wheat caryopsis growth; (ii) to compare physicochemical properties of starches in pericarp and endosperm; (iii) to further discover the relationships between pericarp starches and endosperm starches. Wheat pericarp and endosperm at different development stages were observed by light microscopy and scanning electron microscopy, respectively. Structural properties of starches were determined using X-ray power diffraction and (13) C solid nuclear magnetic resonance. Pericarp starch granules (PSG) accumulated in amyloplasts and chloroplasts, and showed a typical accumulation peak at 5 days after fertilization (DAF), and then gradually decomposed during 5-22 DAF. PSG in the abdominal region showed a higher rate of decomposition compared to the dorsal region of pericarp. Endosperm starch granules (ESG) accumulated in amyloplasts, and occurred in endosperm cells at 5 DAF, then rapidly enriched the endosperm cells until 22 DAF. Compared with ESG, PSG were compound granules of irregular shape and small size distribution. The results also suggested lower amylose content and V-type single-helix content and higher proportions of double helices for PSG compared to ESG. Based on the structural development of PSG and ESG, we speculated that the saccharides resulting from decomposition of PSG, on one hand, enabled the pericarp to survive before maturity of wheat caryopsis and, on the other hand, provided extra nutrition for the growth of ESG. © 2014 Society of Chemical Industry.

Microwave-Assisted Synthesis of CuFe2O4 Nanoparticles and Starch-Based Magnetic Nanocomposites

Directory of Open Access Journals (Sweden)

Gh. Nabiyouni

2013-06-01

Full Text Available Magnetic CuFe2O4 nanoparticles were synthesized by a facile microwave-assisted reaction between Cu(NO32 and Fe(NO33. The magnetic nanoparticles were added to starch to make magnetic polymeric nanocomposite. The nanoparticles and nanocomposites were characterized using X-ray diffraction and scanning electron microscopy. The magnetic properties of the samples were investigated using an alternating gradient force magnetometer (AGFM. The copper ferrite nanoparticles exhibited ferromagnetic behavior at room temperature, with a saturation magnetization of 29emu/g and a coercivity of 136 Oe. The distribution of the CuFe2O4 nanoparticles into the polymeric matrixes decreases the coercivity (136 Oe to 66 Oe. The maximum coercivity of 82 Oe was found for 15% of CuFe2O4 distributed to the starch matrix.

Comparative Transcriptome Analysis Reveals Critical Function of Sucrose Metabolism Related-Enzymes in Starch Accumulation in the Storage Root of Sweet Potato

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Kai Zhang

2017-06-01

Full Text Available The starch properties of the storage root (SR affect the quality of sweet potato (Ipomoea batatas (L. Lam.. Although numerous studies have analyzed the accumulation and properties of starch in sweet potato SRs, the transcriptomic variation associated with starch properties in SR has not been quantified. In this study, we measured the starch and sugar contents and analyzed the transcriptome profiles of SRs harvested from sweet potatoes with high, medium, and extremely low starch contents, at five developmental stages [65, 80, 95, 110, and 125 days after transplanting (DAP]. We found that differences in both water content and starch accumulation in the dry matter affect the starch content of SRs in different sweet potato genotypes. Based on transcriptome sequencing data, we assembled 112336 unigenes, and identified several differentially expressed genes (DEGs involved in starch and sucrose metabolism, and revealed the transcriptional regulatory network controlling starch and sucrose metabolism in sweet potato SRs. Correlation analysis between expression patterns and starch and sugar contents suggested that the sugar–starch conversion steps catalyzed by sucrose synthase (SuSy and UDP-glucose pyrophosphorylase (UGPase may be essential for starch accumulation in the dry matter of SRs, and IbβFRUCT2, a vacuolar acid invertase, might also be a key regulator of starch content in the SRs. Our results provide valuable resources for future investigations aimed at deciphering the molecular mechanisms determining the starch properties of sweet potato SRs.

A Novel Photosynthesis of Carboxymethyl Starch-Stabilized Silver Nanoparticles

Science.gov (United States)

El-Sheikh, M. A.

2014-01-01

The water soluble photoinitiator (PI) 4-(trimethyl ammonium methyl) benzophenone chloride is used for the first time in the synthesis of silver nanoparticles (AgNPs). A new green synthesis method involves using PI/UV system, carboxymethyl starch (CMS), silver nitrate, and water. A mechanism of the reduction of silver ions to AgNPs by PI/UV system as well as by the newly born aldehydic groups was proposed. The synthesis process was assessed by UV-vis spectra and TEM of AgNPs colloidal solution. The highest absorbance was obtained using CMS, PI and AgNO3 concentrations of 10 g/L, 1 g/L, and 1 g/L, respectively; 40°C; 60 min; pH 7; and a material : liquor ratio 1 : 20. AgNPs so-obtained were stable in aqueous solution over a period of three weeks at room temperature (~25°C) and have round shape morphology. The sizes of synthesized AgNPs were in the range of 1–21 nm and the highest counts % of these particles were for particles of 6–10 and 1–3 nm, respectively. PMID:24672325

A Novel Photosynthesis of Carboxymethyl Starch-Stabilized Silver Nanoparticles

Directory of Open Access Journals (Sweden)

M. A. El-Sheikh

2014-01-01

Full Text Available The water soluble photoinitiator (PI 4-(trimethyl ammonium methyl benzophenone chloride is used for the first time in the synthesis of silver nanoparticles (AgNPs. A new green synthesis method involves using PI/UV system, carboxymethyl starch (CMS, silver nitrate, and water. A mechanism of the reduction of silver ions to AgNPs by PI/UV system as well as by the newly born aldehydic groups was proposed. The synthesis process was assessed by UV-vis spectra and TEM of AgNPs colloidal solution. The highest absorbance was obtained using CMS, PI and AgNO3 concentrations of 10 g/L, 1 g/L, and 1 g/L, respectively; 40°C; 60 min; pH 7; and a material : liquor ratio 1 : 20. AgNPs so-obtained were stable in aqueous solution over a period of three weeks at room temperature (~25°C and have round shape morphology. The sizes of synthesized AgNPs were in the range of 1–21 nm and the highest counts % of these particles were for particles of 6–10 and 1–3 nm, respectively.

Application of radiation technology in starch modification

International Nuclear Information System (INIS)

Chen Huiyuan; Peng Zhigang; Ding Zhongmin; Lu Jiajiu

2007-01-01

In order to commercialize the radiation modification of starch, corn starch was irradiated with different dose of 60 Co gamma radiations. Some basic physical and chemical properties of the resulted modified starch paste were measured with emphasis on the viscosity stability and tensile strength. The results indicate that irradiation of corn starch with a dose of 4-10 kGy can decrease its viscosity to 5-14 mPa·s, and the tensile strength can meet the standard set up for textile paste. In comparison with chemical modification for starch, radiation modification is simpler in technology, more convenient in operation, more stable in modification quality, and easier to control. The mechanism of radiation modification of starch was also discussed. (authors)

Defining Starch Binding by Glucan Phosphatases

DEFF Research Database (Denmark)

Auger, Kyle; Raththagala, Madushi; Wilkens, Casper

2015-01-01

Starch is a vital energy molecule in plants that has a wide variety of uses in industry, such as feedstock for biomaterial processing and biofuel production. Plants employ a three enzyme cyclic process utilizing kinases, amylases, and phosphatases to degrade starch in a diurnal manner. Starch...... is comprised of the branched glucan amylopectin and the more linear glucan amylose. Our lab has determined the first structures of these glucan phosphatases and we have defined their enzymatic action. Despite this progress, we lacked a means to quickly and efficiently quantify starch binding to glucan...

Graft polymerization of vinyl acetate onto starch. Saponification to starch-g-poly(vinyl alcohol)

International Nuclear Information System (INIS)

Fanta, G.F.; Burr, R.C.; Doane, W.M.; Russell, C.R.

1979-01-01

Graft polymerizations of vinyl acetate onto granular cornstarch were initiated by cobalt-60 irradiation of starch-monomer-water mixtures, and ungrafted poly(vinyl acetate) was separated from the graft copolymer by benzene extraction. Conversions of monomer to polymer were quantitative at a radiation dose of 1.0 Mrad. Over half of the polymer was present as ungrafted poly(vinyl acetate) (grafting efficiency less than 50%), and the graft copolymer contained only 34% grafted synthetic polymer (34% add-on). Lower irradiation doses produced lower conversions of monomer to polymer and gave graft copolymers with lower % add-on. Addition of minor amounts of acrylamide, methyl acrylate, and methacrylic acid as comonomers produced only small increases in % add-on and grafting efficency. Grafting efficiency was increased to 70% when a monomer mixture containing about 10% methyl methacrylate was used. Grafting efficiency could be increased to over 90% if the graft polymerization of vinyl acetate--methyl methacrylate was carried out near 0 0 C; although conversion of monomers to polymer was low and grafted polymer contained 40 to 50% poly(methyl methacrylate). Selected graft copolymers were treated with methanolic sodium hydroxide to convert starch-g-poly(vinyl acetate) to starch-g-poly(vinyl alcohol). The molecular weight of the poly(vinyl alcohol) moiety was about 30,000. The solubility of starch-g-poly(vinyl alcohol) in hot water was less than 50; however, solubility could be increased by substituting either acid-modified or hypochlorite-oxidized for unmodified starch in the graft polymerization reaction. Vinyl acetate was also graft polymerized onto acid-modified starch which had been dispersed and partially solubilized by heating in water. A total irradiation dose of either 1.0 or 0.5 Mrad gave starch-g-poly

The Research on Thermal Properties and Hydrophobility of the Native Starch/hydrolysis Starch Blends with Treated CaCO3 Powder

Science.gov (United States)

Liu, Chia-I.; Huang, Chi-Yuan

2008-08-01

In this research, hydrolysis starch was added into the starch blends to study the thermal properties. The enthalpy of blends had a significant decrease to 109J/g as content of treated CaCO3 increased to 5wt%. The modified starch was degraded slightly to produce glucose in the hydrolysis treatment. The amount of glucose in native starch and hydrolysis starch was 0.09 μmol and 0.14 μmol by the DNS measurement. Moreover, CaCO3 treated with titanium coupling agent was also added to improve miscibility and hydrophobility in the starch blends. The contact angle of the blends increased from 60° to 95° when 15wt% treated CaCO3 was added. Treated CaCO3 was confirmed to improve the hydrophobility of starch blends effectively.

THE RESEARCH ON THERMAL PROPERTIES AND HYDROPHOBILITY OF THE NATIVE STARCH/HYDROLYSIS STARCH BLENDS WITH TREATED CaCO3 POWDER

International Nuclear Information System (INIS)

Liu, C.-I; Huang, C.-Y.

2008-01-01

In this research, hydrolysis starch was added into the starch blends to study the thermal properties. The enthalpy of blends had a significant decrease to 109J/g as content of treated CaCO 3 increased to 5wt%. The modified starch was degraded slightly to produce glucose in the hydrolysis treatment. The amount of glucose in native starch and hydrolysis starch was 0.09 μmol and 0.14 μmol by the DNS measurement. Moreover, CaCO 3 treated with titanium coupling agent was also added to improve miscibility and hydrophobility in the starch blends. The contact angle of the blends increased from 60 deg. to 95 deg. when 15wt% treated CaCO 3 was added. Treated CaCO 3 was confirmed to improve the hydrophobility of starch blends effectively

Enhanced activity of ADP glucose pyrophosphorylase and formation of starch induced by Azospirillum brasilense in Chlorella vulgaris.

Science.gov (United States)

Choix, Francisco J; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E

2014-05-10

ADP-glucose pyrophosphorylase (AGPase) regulates starch biosynthesis in higher plants and microalgae. This study measured the effect of the bacterium Azospirillum brasilense on AGPase activity in the freshwater microalga Chlorella vulgaris and formation of starch. This was done by immobilizing both microorganisms in alginate beads, either replete with or deprived of nitrogen or phosphorus and all under heterotrophic conditions, using d-glucose or Na-acetate as the carbon source. AGPase activity during the first 72h of incubation was higher in C. vulgaris when immobilized with A. brasilense. This happened simultaneously with higher starch accumulation and higher carbon uptake by the microalgae. Either carbon source had similar effects on enzyme activity and starch accumulation. Starvation either by N or P had the same pattern on AGPase activity and starch accumulation. Under replete conditions, the population of C. vulgaris immobilized alone was higher than when immobilized together, but under starvation conditions A. brasilense induced a larger population of C. vulgaris. In summary, adding A. brasilense enhanced AGPase activity, starch formation, and mitigation of stress in C. vulgaris. Copyright © 2014 Elsevier B.V. All rights reserved.

Modification of potato starch granule structure and morphology in planta by expression of starch binding domain fusion proteins

NARCIS (Netherlands)

Huang, X.

2010-01-01

Producing starches with altered composition, structure and novel physico-chemical properties in planta by manipulating the enzymes which are involved in starch metabolism or (over)expressing heterologous enzymes has huge advantages such as broadening the range of starch applications and reducing the

Some rheological properties of sodium caseinate-starch gels.

Science.gov (United States)

Bertolini, Andrea C; Creamer, Lawrence K; Eppink, Mieke; Boland, Mike

2005-03-23

The influence of sodium caseinate on the thermal and rheological properties of starch gels at different concentrations and from different botanical sources was evaluated. In sodium caseinate-starch gels, for all starches with the exception of potato starch, the sodium caseinate promoted an increase in the storage modulus and in the viscosity of the composite gel when compared with starch gels. The addition of sodium caseinate resulted in an increase in the onset temperature, the gelatinization temperature, and the end temperature, and there was a significant interaction between starch and sodium caseinate for the onset temperature, the peak temperature, and the end temperature. Microscopy results suggested that sodium caseinate promoted an increase in the homogeneity in the matrix of cereal starch gels.

Computational modeling of biodegradable starch based polymer composites

Science.gov (United States)

Joshi, Sachin Sudhakar

2007-12-01

Purpose. The goal of this study is to improve the favorable molecular interactions between starch and PPC by addition of grafting monomers MA and ROM as compatibilizers, which would advance the mechanical properties of starch/PPC composites. Methodology. DFT and semi-empirical methods based calculations were performed on three systems: (a) starch/PPC, (b) starch/PPC-MA, and (c) starch-ROM/PPC. Theoretical computations involved the determination of optimal geometries, binding-energies and vibrational frequencies of the blended polymers. Findings. Calculations performed on five starch/PPC composites revealed hydrogen bond formation as the driving force behind stable composite formation, also confirmed by the negative relative energies of the composites indicating the existence of binding forces between the constituent co-polymers. The interaction between starch and PPC is also confirmed by the computed decrease in stretching CO and OH group frequencies participating in hydrogen bond formation, which agree qualitatively with the experimental values. A three-step mechanism of grafting MA on PPC was proposed to improve the compatibility of PPC with starch. Nine types of 'blends' produced by covalent bond formation between starch and MA-grafted PPC were found to be energetically stable, with blends involving MA grafted at the 'B' and 'C' positions of PPC indicating a binding-energy increase of 6.8 and 6.2 kcal/mol, respectively, as compared to the non-grafted starch/PPC composites. A similar increase in binding-energies was also observed for three types of 'composites' formed by hydrogen bond formation between starch and MA-grafted PPC. Next, grafting of ROM on starch and subsequent blend formation with PPC was studied. All four types of blends formed by the reaction of ROM-grafted starch with PPC were found to be more energetically stable as compared to the starch/PPC composite and starch/PPC-MA composites and blends. A blend of PPC and ROM grafted at the ' �

Poliuretanos elastoméricos obtenidos a partir de aceite de ricino y almidón de yuca original y modificado con anhídrido propiónico: síntesis, propiedades fisicoquímicas y fisicomecánicas Polyurethane elastomers from castor oil and chemically modified yucca starch: synthesis and physical-chemical, physical-mechanical and thermical properties

Directory of Open Access Journals (Sweden)

Manuel F. Valero

2010-01-01

Full Text Available Chemical modification of cassava starch was conducted through an acylation reaction by using pyridine and propionic anhydride to replace the functional groups of starch. Polyurethane elastomers were prepared using suspensions of the mixture obtained from castor oil and yucca starch that was modified by a propionic anhydride reaction. The suspensions were characterized by means of tests based on The Fourier Transform Infrared Spectroscopy and the Hydroxyl Index. The castor oil-AMP suspensions were used for the PU synthesis. The PUs were characterized by their physical-mechanical properties like tension- deformation and Shore A. hardness, thermal gravimetric analysis and swelling test. The density cross-linking of from swelling tests was determined by applying the Flory-Rehner equation.

Enzyme-Catalyzed Regioselective Modification of Starch Nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Chakraborty, Soma [Polytechnic Univ., Brooklyn, NY (United States). National Science Foundation (NSF) Center for Biocatalysis and Bioprocessing of Macromolecules, Othmer Dept. of Chemical and Biological Science and Engineering; Sahoo, Bishwabhusan [Polytechnic Univ., Brooklyn, NY (United States). National Science Foundation (NSF) Center for Biocatalysis and Bioprocessing of Macromolecules, Othmer Dept. of Chemical and Biological Science and Engineering; Teraoka, Iwao [Polytechnic Univ., Brooklyn, NY (United States). National Science Foundation (NSF) Center for Biocatalysis and Bioprocessing of Macromolecules, Othmer Dept. of Chemical and Biological Science and Engineering; Miller, Lisa M. [Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source (NSLS); Gross, Richard A. [Polytechnic Univ., Brooklyn, NY (United States). National Science Foundation (NSF) Center for Biocatalysis and Bioprocessing of Macromolecules, Othmer Dept. of Chemical and Biological Science and Engineering

2004-12-13

The selective esterification of starch nanoparticles was performed using as catalyst Candida antartica Lipase B (CAL-B) in its immobilized (Novozym 435) and free (SP-525) forms. The starch nanoparticles were made accessible for acylation reactions by formation of Aerosol-OT (AOT, bis(2-ethylhexyl)sodium sulfosuccinate) stabilized microemulsions. Starch nanoparticles in microemulsions were reacted with vinyl stearate, ε-caprolactone, and maleic anhydride at 40 °C for 48 h to give starch esters with degrees of substitution (DS) of 0.8, 0.6, and 0.4, respectively. Substitution occurred regioselectively at the C-6 position of the glucose repeat units. Infrared microspectroscopy (IRMS) revealed that AOT-coated starch nanoparticles diffuse into the outer 50 μm shell of catalyst beads. Thus, even though CAL-B is immobilized within a macroporous resin, CAL-B is sufficiently accessible to the starch nanoparticles. When free CAL-B was incorporated along with starch within AOT-coated reversed micelles, CAL-B was also active and catalyzed the acylation with vinyl stearate (24 h, 40 °C) to give DS = 0.5. After removal of surfactant from the modified starch nanoparticles, they were dispersed in DMSO or water and were shown to retain their nanodimensions.

Potential of Starch Nanocomposites for Biomedical Applications

Science.gov (United States)

Zakaria, N. H.; Muhammad, N.; Abdullah, M. M. A. B.

2017-06-01

In recent years, the development of biodegradable materials from renewable sources based on polymeric biomaterials have grown rapidly due to increase environmental concerns and the shortage of petroleum sources. In this regard, naturally renewable polymers such as starch has shown great potential as environmental friendly materials. Besides, the unique properties of starch such as biodegradable and non-toxic, biocompatible and solubility make them useful for a various biomedical applications. Regardless of their unique properties, starch materials are known to have limitations in term of poor processability, low mechanical properties, poor long term stability and high water sensitivity. In order to overcome these limitations, the incorporation of nano size fillers into starch materials (nanocomposites) has been introduced. This review aims to give an overview about structure and characteristics of starch, modification of starch by nanocomposites and their potential for biomedical applications.

Structural and molecular basis of starch viscosity in hexaploid wheat.

Science.gov (United States)

Ral, J-P; Cavanagh, C R; Larroque, O; Regina, A; Morell, M K

2008-06-11

Wheat starch is considered to have a low paste viscosity relative to other starches. Consequently, wheat starch is not preferred for many applications as compared to other high paste viscosity starches. Increasing the viscosity of wheat starch is expected to increase the functionality of a range of wheat flour-based products in which the texture is an important aspect of consumer acceptance (e.g., pasta, and instant and yellow alkaline noodles). To understand the molecular basis of starch viscosity, we have undertaken a comprehensive structural and rheological analysis of starches from a genetically diverse set of wheat genotypes, which revealed significant variation in starch traits including starch granule protein content, starch-associated lipid content and composition, phosphate content, and the structures of the amylose and amylopectin fractions. Statistical analysis highlighted the association between amylopectin chains of 18-25 glucose residues and starch pasting properties. Principal component analysis also identified an association between monoesterified phosphate and starch pasting properties in wheat despite the low starch-phosphate level in wheat as compared to tuber starches. We also found a strong negative correlation between the phosphate ester content and the starch content in flour. Previously observed associations between internal starch granule fatty acids and the swelling peak time and pasting temperature have been confirmed. This study has highlighted a range of parameters associated with increased starch viscosity that could be used in prebreeding/breeding programs to modify wheat starch pasting properties.

Development of oxidised and heat-moisture treated potato starch film.

Science.gov (United States)

Zavareze, Elessandra da Rosa; Pinto, Vânia Zanella; Klein, Bruna; El Halal, Shanise Lisie Mello; Elias, Moacir Cardoso; Prentice-Hernández, Carlos; Dias, Alvaro Renato Guerra

2012-05-01

This study investigated the effects of sodium hypochlorite oxidation and a heat-moisture treatment of potato starch on the physicochemical, pasting and textural properties of potato starches in addition to the water vapour permeability (WVP) and mechanical properties of potato starch films produced from these starches. The carbonyl contents, carboxyl contents, swelling power, solubility, pasting properties and gel texture of the native, oxidised and heat-moisture treated (HMT) starches were evaluated. The films made of native, oxidised and HMT starches were characterised by thickness, water solubility, colour, opacity, mechanical properties and WVP. The oxidised and HMT starches had lower viscosity and swelling power compared to the native starch. The films produced from oxidised potato starch had decreased solubility, elongation and WVP values in addition to increased tensile strength compared to the native starch films. The HMT starch increased the tensile strength and WVP of the starch films compared to the native starch. Copyright © 2011 Elsevier Ltd. All rights reserved.

Microstructure, thermal properties and crystallinity of amadumbe starch nanocrystals.

Science.gov (United States)

Mukurumbira, Agnes; Mariano, Marcos; Dufresne, Alain; Mellem, John J; Amonsou, Eric O

2017-09-01

Amadumbe (Colocasia esculenta), commonly known as taro is a tropical tuber that produces starch-rich underground corms. In this study, the physicochemical properties of starch nanocrystals (SNC) prepared by acid hydrolysis of amadumbe starches were investigated. Two varieties of amadumbe corms were used for starch extraction. Amadumbe starches produced substantially high yield (25%) of SNC's. These nanocrystals appeared as aggregated and individual particles and possessed square-like platelet morphology with size: 50-100nm. FTIR revealed high peak intensities corresponding to OH stretch, CH stretch and H 2 O bending vibrations for SNCs compared to their native starch counterparts. Both the native starch and SNC exhibited the A-type crystalline pattern. However, amadumbe SNCs showed higher degree of crystallinity and slightly reduced melting temperatures than their native starches. Amadumbe SNCs presented similar thermal decomposition property as their native starches. Amadumbe starch nanocrystals may have potential application in biocomposite films due to their square-like platelet morphology. Copyright © 2017 Elsevier B.V. All rights reserved.

An Environmental Impact Analysis of Semi-Mechanical Extraction Process of Sago Starch: Life Cycle Assessment (LCA) Perspective

Science.gov (United States)

Yusuf, M. A.; Romli, M.; Suprihatin; Wiloso, E. I.

2018-05-01

Industrial activities use material, energy and water resources and generate greenhouse gas (GHG). Currently, various regulations require industry to measure and quantify the emissions generated from its process activity. LCA is a method that can be used to analyze and report the environmental impact of an activity that uses resources and generates waste by an industrial activity. In this work, LCA is used to determine the environmental impact of a semi-mechanical extraction process of sago industry. The data was collected through the sago industry in Cimahpar, Bogor. The extraction of sago starch consists of stem cutting, rasping, mixing, filtration, starch sedimentation, washing, and drying. The scope of LCA study covers the harvesting of sago stem, transportation to extraction site, and the starch extraction process. With the assumption that the average transportation distance of sago stem to extraction site is 200 km, the GHG emission is estimated to be 325 kg CO2 eq / ton of sundried sago starch. This figure is lower than that reported for maize starch (1120 kg CO2 eq), potato starch (2232 kg CO2 eq) and cassava starch (4310 kg CO2 eq). This is most likely due to the uncounted impact from the use of electrical energy on the extraction process, which is currently being conducted. A follow-up study is also underway to formulate several process improvement scenarios to derive the design of sago starch processing that generates the minimum emissions.

The Starch Granule-Associated Protein EARLY STARVATION1 Is Required for the Control of Starch Degradation in Arabidopsis thaliana Leaves[OPEN

Science.gov (United States)

Feike, Doreen; Seung, David; Graf, Alexander; Bischof, Sylvain; Ellick, Tamaryn; Coiro, Mario; Soyk, Sebastian; Eicke, Simona; Mettler-Altmann, Tabea; Lu, Kuan Jen; Trick, Martin; Zeeman, Samuel C.

2016-01-01

To uncover components of the mechanism that adjusts the rate of leaf starch degradation to the length of the night, we devised a screen for mutant Arabidopsis thaliana plants in which starch reserves are prematurely exhausted. The mutation in one such mutant, named early starvation1 (esv1), eliminates a previously uncharacterized protein. Starch in mutant leaves is degraded rapidly and in a nonlinear fashion, so that reserves are exhausted 2 h prior to dawn. The ESV1 protein and a similar uncharacterized Arabidopsis protein (named Like ESV1 [LESV]) are located in the chloroplast stroma and are also bound into starch granules. The region of highest similarity between the two proteins contains a series of near-repeated motifs rich in tryptophan. Both proteins are conserved throughout starch-synthesizing organisms, from angiosperms and monocots to green algae. Analysis of transgenic plants lacking or overexpressing ESV1 or LESV, and of double mutants lacking ESV1 and another protein necessary for starch degradation, leads us to propose that these proteins function in the organization of the starch granule matrix. We argue that their misexpression affects starch degradation indirectly, by altering matrix organization and, thus, accessibility of starch polymers to starch-degrading enzymes. PMID:27207856

Influence of crop load on the expression patterns of starch metabolism genes in alternate-bearing citrus trees.

Science.gov (United States)

Nebauer, Sergio G; Renau-Morata, Begoña; Lluch, Yolanda; Baroja-Fernández, Edurne; Pozueta-Romero, Javier; Molina, Rosa-Victoria

2014-07-01

The fruit is the main sink organ in Citrus and captures almost all available photoassimilates during its development. Consequently, carbohydrate partitioning and starch content depend on the crop load of Citrus trees. Nevertheless, little is known about the mechanisms controlling the starch metabolism at the tree level in relation to presence of fruit. The aim of this study was to find the relation between the seasonal variation of expression and activity of the genes involved in carbon metabolism and the partition and allocation of carbohydrates in 'Salustiana' sweet orange trees with different crop loads. Metabolisable carbohydrates, and the expression and activity of the enzymes involved in sucrose and starch metabolism, including sucrose transport, were determined during the year in the roots and leaves of 40-year-old trees bearing heavy crop loads ('on' trees) and trees with almost no fruits ('off' trees). Fruit altered photoassimilate partitioning in trees. Sucrose content tended to be constant in roots and leaves, and surplus fixed carbon is channeled to starch production. Differences between 'on' and 'off' trees in starch content can be explained by differences in ADP-glucose pyrophosphorylase (AGPP) expression/activity and α-amylase activity which varies depending on crop load. The observed relation of AGPP and UGPP (UDP-glucose pyrophosphorylase) is noteworthy and indicates a direct link between sucrose and starch synthesis. Furthermore, different roles for sucrose transporter SUT1 and SUT2 have been proposed. Variation in soluble sugars content cannot explain the differences in gene expression between the 'on' and 'off' trees. A still unknown signal from fruit should be responsible for this control. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Use of enzymes to minimize the rheological dough problems caused by high levels of damaged starch in starch-gluten systems.

Science.gov (United States)

Barrera, Gabriela N; León, Alberto E; Ribotta, Pablo D

2016-05-01

During wheat milling, starch granules can experience mechanical damage, producing damaged starch. High levels of damaged starch modify the physicochemical properties of wheat flour, negatively affecting the dough behavior as well as the flour quality and cookie and bread making quality. The aim of this work was to evaluate the effect of α-amylase, maltogenic amylase and amyloglucosidase on dough rheology in order to propose alternatives to reduce the issues related to high levels of damaged starch. The dough with a high level of damaged starch became more viscous and resistant to deformations as well as less elastic and extensible. The soluble fraction of the doughs influenced the rheological behavior of the systems. The α-amylase and amyloglucosidase reduced the negative effects of high damaged starch contents, improving the dough rheological properties modified by damaged starch. The rheological behavior of dough with the higher damaged-starch content was related to a more open gluten network arrangement as a result of the large size of the swollen damaged starch granules. We can conclude that the dough rheological properties of systems with high damaged starch content changed positively as a result of enzyme action, particularly α-amylase and amyloglucosidase additions, allowing the use of these amylases and mixtures of them as corrective additives. Little information was reported about amyloglucosidase activity alone or combined with α-amylase. The combinations of these two enzymes are promising to minimize the negative effects caused by high levels of damaged starch on product quality. More research needs to be done on bread quality combining these two enzymes. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

The effect of starch-garlic powder ratio on degradation rate of Gadung starch bioplastic

Science.gov (United States)

Mairiza, L.; Mariana; Ramadhany, M.; Feviyussa, C. A.

2018-03-01

Bioplastic is one of the solutions for environmental problems caused by plastics waste. Utilization of toxic gadung starch in the manufacturing of bioplastic would be as an alternative, due to gadung bulb has high starch content, and it is still not used optimally. This research aimed to learn about the using of gadung starch-mixed with garlic powder of making biodegradable plastic packaging. Also, to observe the duration of degradation, as a level of biodegradability of plastic film produced. The method used making this bioplastic was casting method. The variables used in this study were the ratios of starch and powdered garlic, were 10:0; 8:2; 6:4, and the concentration of garlic powder were 2%; 4%; 6%; and 8 %. The degradation test was done by soil burial test. The results of the soil burial test shown that the film was more rapidly degraded at ratio of 6: 4 compared to the ratio of 8: 2 and 10: 0. The results shown that bioplastic at the starch-garlic powder ratio of 10: 0 was decomposed in 21 days, at the the ratio of 8:2 was 15 days, while at the ratio of 6:4, the plastic film was degraded in the 11 days.

Characterization of Native and Modified Starches by Potentiometric Titration

OpenAIRE

Soto, Diana; Urdaneta, Jose; Pernia, Kelly

2014-01-01

The use of potentiometric titration for the analysis and characterization of native and modified starches is highlighted. The polyelectrolytic behavior of oxidized starches (thermal and thermal-chemical oxidation), a graft copolymer of itaconic acid (IA) onto starch, and starch esters (mono- and diester itaconate) was compared with the behavior of native starch, the homopolymer, and the acid employed as a graft monomer and substituent. Starch esters showed higher percentages of acidity, follo...

Characterization of starch films containing starch nanoparticles. Part 2: viscoelasticity and creep properties.

Science.gov (United States)

Shi, Ai-Min; Wang, Li-Jun; Li, Dong; Adhikari, Benu

2013-07-25

Starch films were successfully produced by incorporating spray dried and vacuum-freeze dried starch nanoparticles. The frequency sweep, creep-recovery behavior and time-temperature superposition (TTS) on these films were studied. All these films exhibited dominant elastic behavior (than viscous behavior) over the entire frequency range (0.1-100 rad/s). The incorporation of both types of starch nanoparticles increased the storage and loss modulus, tanδ, creep strain, creep compliance and creep rate at long time frame and reduced the recovery rate of films while the effect of different kinds of starch nanoparticles on these parameters was similar both in magnitude and trend. TTS method was successfully used to predict long time (over 20 days) creep behavior through the master curves. The addition of these nanoparticles could increase the activation energy parameter used in TTS master curves. Power law and Burger's models were capable of fitting storage and loss modulus (R(2)>0.79) and creep data (R(2)>0.96), respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Atomic force microscopy of starch systems.

Science.gov (United States)

Zhu, Fan

2017-09-22

Atomic force microscopy (AFM) generates information on topography, adhesion, and elasticity of sample surface by touching with a tip. Under suitable experimental settings, AFM can image biopolymers of few nanometers. Starch is a major food and industrial component. AFM has been used to probe the morphology, properties, modifications, and interactions of starches from diverse botanical origins at both micro- and nano-structural levels. The structural information obtained by AFM supports the blocklet structure of the granules, and provides qualitative and quantitative basis for some physicochemical properties of diverse starch systems. It becomes evident that AFM can complement other microscopic techniques to provide novel structural insights for starch systems.

Studies on rye starch properties and modification. Pt. 1. Composition and properties of rye starch granules

Energy Technology Data Exchange (ETDEWEB)

Schierbaum, F; Radosta, S; Richter, M; Kettlitz, B [Zentralinstitut fuer Ernaehrung, Potsdam (Germany); Gernat, C [Zentralinstitut fuer Molekularbiologie, Berlin (Germany)

1991-09-01

Rye is considered as a potential raw material for starch industry. Starting from a survey of technical procedures of isolating starches from rye-flour and -grits investigations will be reported, which were performed on pilot plant- and laboratory-isolated rye starches. The present paper deals with its granule appearance and composition. A distribution of granule size between small granules ({<=} 10 {mu}m - 15%) and large granules ({>=} 11 ... {<=} 40 {mu}m = 85%) is typical for the totality of the starches. Differing distributions depend on the conditions of isolation: The entity of starch containing samples resulted from the latoratory procedures under investigation. Large-granule starch preparations were isolated in the pilot plant: The centrifuge-overflow contains the small-granule fraction which is high in impurities. Granule crystallinity amounts to 16%. The crystalline component - like in wheat and triticale starches - consists predominantly of A-polymorph - with up to 9% of the B-type. The isotherms of water exchange are of the cereal type. The contents of minor constituents largely relate to the small granule fraction which assembles the majority of crude protein, pentosans and lipids, which are difficult to remove. Lipid components in all fractions influence the results of linear chain-iodine interactions and they must be removed to proceed from apparent to absolute polysaccharide indices. The absolute amylose contents amount to {approx equal} 25% for large granule samples and to 20-21% for small granule samples. The average chain-length of iodine binding helical regions was determined with 220-240 AGU. (orig.).

Microbial production of raw starch digesting enzymes | Sun | African ...

African Journals Online (AJOL)

Raw starch digesting enzymes refer to enzymes that can act directly on raw starch granules below the gelatinization temperature of starch. With the view of energy-saving, a worldwide interest has been focused on raw starch digesting enzymes in recent years, especially since the oil crisis of 1973. Raw starch digesting ...

Heme-dependent Metabolite Switching Regulates H2S Synthesis in Response to Endoplasmic Reticulum (ER) Stress.

Science.gov (United States)

Kabil, Omer; Yadav, Vinita; Banerjee, Ruma

2016-08-05

Substrate ambiguity and relaxed reaction specificity underlie the diversity of reactions catalyzed by the transsulfuration pathway enzymes, cystathionine β-synthase (CBS) and γ-cystathionase (CSE). These enzymes either commit sulfur metabolism to cysteine synthesis from homocysteine or utilize cysteine and/or homocysteine for synthesis of H2S, a signaling molecule. We demonstrate that a kinetically controlled heme-dependent metabolite switch in CBS regulates these competing reactions where by cystathionine, the product of CBS, inhibits H2S synthesis by the second enzyme, CSE. Under endoplasmic reticulum stress conditions, induction of CSE and up-regulation of the CBS inhibitor, CO, a product of heme oxygenase-1, flip the operating preference of CSE from cystathionine to cysteine, transiently stimulating H2S production. In contrast, genetic deficiency of CBS leads to chronic stimulation of H2S production. This metabolite switch from cystathionine to cysteine and/or homocysteine renders H2S synthesis by CSE responsive to the known modulators of CBS: S-adenosylmethionine, NO, and CO. Used acutely, it regulates H2S synthesis; used chronically, it might contribute to disease pathology. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Starch Biosynthesis during Pollen Maturation Is Associated with Altered Patterns of Gene Expression in Maize1

Science.gov (United States)

Datta, Rupali; Chamusco, Karen C.; Chourey, Prem S.

2002-01-01

Starch biosynthesis during pollen maturation is not well understood in terms of genes/proteins and intracellular controls that regulate it in developing pollen. We have studied two specific developmental stages: “early,” characterized by the lack of starch, before or during pollen mitosis I; and “late,” an actively starch-filling post-pollen mitosis I phase in S-type cytoplasmic male-sterile (S-CMS) and two related male-fertile genotypes. The male-fertile starch-positive, but not the CMS starch-deficient, genotypes showed changes in the expression patterns of a large number of genes during this metabolic transition. In addition to a battery of housekeeping genes of carbohydrate metabolism, we observed changes in hexose transporter, plasma membrane H+-ATPase, ZmMADS1, and 14-3-3 proteins. Reduction or deficiency in 14-3-3 protein levels in all three major cellular sites (amyloplasts [starch], mitochondria, and cytosol) in male-sterile relative to male-fertile genotypes are of potential interest because of interorganellar communication in this CMS system. Further, the levels of hexose sugars were significantly reduced in male-sterile as compared with male-fertile tissues, not only at “early” and “late” stages but also at an earlier point during meiosis. Collectively, these data suggest that combined effects of both reduced sugars and their reduced flux in starch biosynthesis along with a strong possibility for altered redox passage may lead to the observed temporal changes in gene expressions, and ultimately pollen sterility. PMID:12481048

( Phaseolus lunatus ) starch as a tablet disintegrant

African Journals Online (AJOL)

) was evaluated. The starch from the seeds was extracted and its disintegrant ability was compared with that of maize starch BP in paracetamol based tablets at concentrations of 0, 2.5, 5, 7.5 and 10 %w/w. The following properties of the starch ...

Antimicrobial nanostructured starch based films for packaging.

Science.gov (United States)

Abreu, Ana S; Oliveira, M; de Sá, Arsénio; Rodrigues, Rui M; Cerqueira, Miguel A; Vicente, António A; Machado, A V

2015-09-20

Montmorillonite modified with a quaternary ammonium salt C30B/starch nanocomposite (C30B/ST-NC), silver nanoparticles/starch nanocomposite (Ag-NPs/ST-NC) and both silver nanoparticles/C30B/starch nanocomposites (Ag-NPs/C30B/ST-NC) films were produced. The nanoclay (C30B) was dispersed in a starch solution using an ultrasonic probe. Different concentrations of Ag-NPs (0.3, 0.5, 0.8 and 1.0mM) were synthesized directly in starch and in clay/starch solutions via chemical reduction method. Dispersion of C30B silicate layers and Ag-NPs in ST films characterized by X-ray and scanning electron microscopy showed that the presence of Ag-NPs enhanced clay dispersion. Color and opacity measurements, barrier properties (water vapor and oxygen permeabilities), dynamic mechanical analysis and contact angle were evaluated and related with the incorporation of C30B and Ag-NPs. Films presented antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans without significant differences between Ag-NPs concentrations. The migration of components from the nanostructured starch films, assessed by food contact tests, was minor and under the legal limits. These results indicated that the starch films incorporated with C30B and Ag-NPs have potential to be used as packaging nanostructured material. Copyright © 2015 Elsevier Ltd. All rights reserved.

Amylase catalyzed synthesis of glycosyl acrylates and their polymerization

NARCIS (Netherlands)

Kloosterman, Wouter M.J.; Jovanovic, Danijela; Brouwer, Sander; Loos, Katja

2014-01-01

The enzymatic synthesis of novel (di)saccharide acrylates from starch and 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and 4-hydroxybutyl acrylate (2-HEA, 2-HEMA and 4-HBA) catalyzed by various commercially available amylase preparations is demonstrated. Both liquefaction and

Development of waxy cassava with different Biological and physico-chemical characteristics of starches for industrial applications.

Science.gov (United States)

Zhao, Shan-Shan; Dufour, Dominique; Sánchez, Teresa; Ceballos, Hernan; Zhang, Peng

2011-08-01

The quality of cassava starch, an important trait in cassava breeding programs, determines its applications in various industries. For example, development of waxy (having a low level of amylose) cassava is in demand. Amylose is synthesized by granule-bound starch synthase I (GBSSI) in plants, and therefore, down-regulation of GBSSI expression in cassava might lead to reduced amylose content. We produced 63 transgenic cassava plant lines that express hair-pin dsRNAs homologous to the cassava GBSSI conserved region under the control of the vascular-specific promoter p54/1.0 from cassava (p54/1.0::GBSSI-RNAi) or cauliflower mosaic virus (CaMV) 35S (35S::GBSSI-RNAi). After the screening storage roots and starch granules from field-grown plants with iodine staining, the waxy phenotype was discovered: p54/1.0::GBSSI-RNAi line A8 and 35S::GBSSI-RNAi lines B9, B10, and B23. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that there was no detectable GBSSI protein in the starch granules of plants with the waxy phenotype. Further, the amylose content of transgenic starches was significantly reduced (industrial utilization. Copyright © 2011 Wiley Periodicals, Inc.

Radiation processing of starch

International Nuclear Information System (INIS)

Kamaruddin Hashim

2008-01-01

Starch is a polysaccharide material and generally, it is non-toxic, biocompatible and biodegradable. It mainly use as foodstuff, food additives, production of sugar and flavouring. Sago palm with scientific name Genus Metroxylon belonging to family Palmae is an important resource in the production of sago starch in Malaysia. Nearly 90% of sago planting areas is found in Sarawak State of Malaysia. It can easily grow under the harsh swampy environment. The sago starch content 4% polyphenol, which is an active compound with antioxidant property that has potential benefit in health and skin care applications. Renewal resources and environmental friendly of natural polymer reason for the researcher to explore the potential of this material in order to improve our quality of live. (author)

Development of starch-based materials

NARCIS (Netherlands)

Habeych Narvaez, E.A.

2009-01-01

Starch-based materials show potential as fully degradable plastics. However, the current
applicability of these materials is limited due to their poor moisture tolerance and
mechanical properties. Starch is therefore frequently blended with other polymers to make
the material more

Starch bioengineering affects cereal grain germination and seedling establishment

DEFF Research Database (Denmark)

Shaik, Shahnoor Sultana; Carciofi, Massimiliano; Martens, Helle Juel

2014-01-01

Cereal grain germination is central for plant early development, and efficient germination has a major role in crop propagation and malting. Endosperm starch is the prime energy reserve in germination and seedling establishment. In this study, it was hypothesized that optimized starch granule...... structure, and not only the endosperm starch content per se, is important for germination and seedling establishment. For that purpose, wild-type (WT), and specifically engineered degradable hyperphosphorylated (HP) starch and more resistant amylose-only (AO) starch barley lines were used. The transgenics...... showed no severe phenotypes and the WT and HP lines degraded the starch similarly, having 30% residual starch after 12 d of germination. However, the AO line showed significant resistance to degradation, having 57% residual starch. Interestingly, protein and β-glucan (BG) degradation was stimulated...

Effect of genotype and environment on the concentrations of starch and protein in, and the physicochemical properties of starch from, field pea and fababean.

Science.gov (United States)

Hood-Niefer, Shannon D; Warkentin, Thomas D; Chibbar, Ravindra N; Vandenberg, Albert; Tyler, Robert T

2012-01-15

The effects of genotype and environment and their interaction on the concentrations of starch and protein in, and the amylose content and thermal and pasting properties of starch from, pea and fababean are not well known. Differences due to genotype were observed in the concentrations of starch and protein in pea and fababean, in the onset temperature (To) and peak temperature (Tp) of gelatinization of fababean starch, and in the pasting, trough, cooling and final viscosities of pea starch and fababean starch. Significant two-way interactions (location × genotype) were observed for the concentration of starch in fababean and the amylose content, To, endothermic enthalpy of gelatinization (ΔH) and trough viscosity of fababean starch. Significant three-way interactions (location × year × genotype) were observed for the concentration of starch in pea and the pasting, trough, cooling and final viscosities of pea starch. Differences observed in the concentrations of starch and protein in pea and fababean were sufficient to be of practical significance to end-users, but the relatively small differences in amylose content and physicochemical properties of starch from pea and fababean were not. Copyright © 2011 Society of Chemical Industry.

Barley starch bioengineering for high phosphate and amylose

DEFF Research Database (Denmark)

Blennow, Per Gunnar Andreas; Carciofi, Massimiliano; Shaik, Shahnoor Sultana

2011-01-01

Starch is a biological polymer that can be industrially produced in massive amounts in a very pure form. Cereals is the main source for starch production and any improvement of the starch fraction can have a tremendous impact in food and feed applications. Barley ranks number four among cereal...... crops and barley is a genetically very well characterized. Aiming at producing new starch qualities in the cereal system, we used RNAi and overexpression strategies to produce pure amylose and high-phosphate starch, respectively, using the barley kernel as a polymer factory. By simultaneous silencing...... of the three genes encoding the starch-branching enzymes SBEI, SBEIIa, and SBEIIb using a triple RNAi chimeric hairpin construct we generated a virtually amylopectin-free barley. The grains of the transgenic lines were shrunken and had a yield of around 80% of the control line. The starch granules were...

Up-Scaling Production of Carboxymethyl Starch

International Nuclear Information System (INIS)

Mohd Hafiz Abdul Nasir; Zainon Othman; Kamaruddin Hashim; Siti Khadijah Abu Hadin; Nurul Nadia Shaaban

2015-01-01

Carboxymethyl starch (CMS) is a starch derivative formed by its reaction with sodium monochloroacetate which consist of OH-groups that are partially or completely replaced by ether substitution. Characteristic of CMSS defined by the degree of substitution (DS). DS is defined as the average number of substituents per anhydro glucose unit (AGU), the monomer unit of starch. The upgrading of CMSS production from 10L to 30L requires several experiments with different variable such as amount NaOH, amount of Sago Starch and reaction time. Each will give different DS. Quality control for the product cover moisture, viscosity and paste clarity. Therefore, SOP has been established to control the quality final product. (author)

Methanol Metabolism in Yeasts : Regulation of the Synthesis of Catabolic Enzymes

NARCIS (Netherlands)

Egli, Th.; Dijken, J.P. van; Veenhuis, M.; Harder, W.; Fiechter, A.

1980-01-01

The regulation of the synthesis of four dissimilatory enzymes involved in methanol metabolism, namely alcohol oxidase, formaldehyde dehydrogenase, formate dehydrogenase and catalase was investigated in the yeasts Hansenula polymorpha and Kloeckera sp. 2201. Enzyme profiles in cell-free extracts of

Hot-melt extrusion of sugar-starch-pellets.

Science.gov (United States)

Yeung, Chi-Wah; Rein, Hubert

2015-09-30

Sugar-starch-pellets (syn. sugar spheres) are usually manufactured through fluidized bed granulation or wet extrusion techniques. This paper introduces hot-melt extrusion (HME) as an alternative method to manufacture sugar-starch-pellets. A twin-screw extruder coupled with a Leistritz Micro Pelletizer (LMP) cutting machine was utilized for the extrusion of different types (normal-, waxy-, and high-amlyose) of corn starch, blended with varying amounts of sucrose. Pellets were characterized for their physicochemical properties including crystallinity, particle size distribution, tensile strength, and swelling expansion. Furthermore, the influence of sugar content and humidity on the product was investigated. Both sucrose and water lowered the Tg of the starch system allowing a convenient extrusion process. Mechanical strength and swelling behavior could be associated with varying amylose and amylopectin. X-ray powder diffractometric (XRPD) peaks of increasing sucrose contents appeared above 30%. This signified the oversaturation of the extruded starch matrix system with sucrose. Otherwise, had the dissolved sucrose been embedded into the molten starch matrix, no crystalline peak could have been recognized. The replacement of starch with sucrose reduced the starch pellets' swelling effect, which resulted in less sectional expansion (SEI) and changed the surface appearance. Further, a nearly equal tensile strength could be detected for sugar spheres with more than 40% sucrose. This observation stands in good relation with the analyzed values of the commercial pellets. Both techniques (fluidized bed and HME) allowed a high yield of spherical pellets (less friability) for further layering processes. Thermal influence on the sugar-starch system is still an obstacle to be controlled. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of gamma irradiation on thermophysical properties of plasticized starch and starch surfactant films

Science.gov (United States)

Cieśla, Krystyna; Watzeels, Nick; Rahier, Hubert

2014-06-01

In this work the influence of gamma irradiation on the thermomechanical properties of the films formed in potato starch-glycerol and potato starch-glycerol-surfactant systems were examined by Dynamic Mechanical Analysis, DMA, and Differential Scanning Calorimetry, DSC, and the results were correlated to the amount of the volatile fraction in the films.

Regulation of photosynthesis by end-product accumulation in leaves of plants storing starch, sucrose, and hexose sugars.

Science.gov (United States)

Goldschmidt, E E; Huber, S C

1992-08-01

In the present study, leaves of different plant species were girdled by the hot wax collar method to prevent export of assimilates. Photosynthetic activity of girdled and control leaves was evaluated 3 to 7 days later by two methods: (a) carbon exchange rate (CER) of attached leaves was determined under ambient CO(2) concentrations using a closed gas system, and (b) maximum photosynthetic capacity (A(max)) was determined under 3% CO(2) with a leaf disc O(2) electrode. Starch, hexoses, and sucrose were determined enzymically. Typical starch storers like soybean (Glycine max L.) (up to 87.5 milligrams of starch per square decimeter in girdled leaves), cotton (Gossypium hirsutum L.), and cucumber (Cucumis sativus L.) responded to 7 days of girdling by increased (80-100%) stomatal resistance (r(s)) and decreased A(max) (>50%). On the other hand, spinach (Spinacia oleracea L.), a typical sucrose storer (up to 160 milligrams of sucrose per square decimeter in girdled leaves), showed only a slight reduction in CER and almost no change in A(max). Intermediate plants like tomato (Lycopersicon esculentum Mill.), sunflower (Helianthus annuus L.), broad bean (Vicia faba L.), bean (Phaseolus vulgaris L.), and pea (Pisum sativum L.), which upon girdling store both starch and sucrose, responded to the girdle by a considerable reduction in CER but only moderate inhibition of A(max), indicating that the observed reduction in CER was primarily a stomatal response. Both the wild-type tobacco (Nicotiana sylvestris) (which upon girdling stored starch and hexoses) and the starchless mutant (which stored only hexoses, up to 90 milligrams per square decimeter) showed 90 to 100% inhibition of CER and approximately 50% inhibition of A(max). In general, excised leaves (6 days) behaved like girdled leaves of the respective species, showing 50% reduction of A(max) in wild-type and starchless N. sylvestris but only slight decline of A(max) in spinach. The results of the present study

Starch bioengineering in Brachypodium distachyon

DEFF Research Database (Denmark)

Tanackovic, Vanja; Svensson, Jan Tommy; Buleon, A

2011-01-01

Brachypodium distachyon was recently introduced as a model plant for temperate cereals (Opanowicz et al., 2008). We aim to establish Brachypodium as a model for cereal starch metabolism. Grain starch from two lines: Bd21 and Bd21-3 are being characterized. Microscopic, chemical and structural data...... including amylopectin chain length distribution, phosphate content and amylose content provided further evidence for the close relationship to temperate cereals even though starch content and starch granule size were considerably lower than that for barley (Hordeum vulgare). Bioinformatics analyses...... in temperate cereals....

Mammalian mucosal α-glucosidases coordinate with α-amylase in the initial starch hydrolysis stage to have a role in starch digestion beyond glucogenesis.

Science.gov (United States)

Dhital, Sushil; Lin, Amy Hui-Mei; Hamaker, Bruce R; Gidley, Michael J; Muniandy, Anbuhkani

2013-01-01

Starch digestion in the human body is typically viewed in a sequential manner beginning with α-amylase and followed by α-glucosidase to produce glucose. This report indicates that the two enzyme types can act synergistically to digest granular starch structure. The aim of this study was to investigate how the mucosal α-glucosidases act with α-amylase to digest granular starch. Two types of enzyme extracts, pancreatic and intestinal extracts, were applied. The pancreatic extract containing predominantly α-amylase, and intestinal extract containing a combination of α-amylase and mucosal α-glucosidase activities, were applied to three granular maize starches with different amylose contents in an in vitro system. Relative glucogenesis, released maltooligosaccharide amounts, and structural changes of degraded residues were examined. Pancreatic extract-treated starches showed a hydrolysis limit over the 12 h incubation period with residues having a higher gelatinization temperature than the native starch. α-Amylase combined with the mucosal α-glucosidases in the intestinal extract showed higher glucogenesis as expected, but also higher maltooligosaccharide amounts indicating an overall greater degree of granular starch breakdown. Starch residues after intestinal extract digestion showed more starch fragmentation, higher gelatinization temperature, higher crystallinity (without any change in polymorph), and an increase of intermediate-sized or small-sized fractions of starch molecules, but did not show preferential hydrolysis of either amylose or amylopectin. Direct digestion of granular starch by mammalian recombinant mucosal α-glucosidases was observed which shows that these enzymes may work either independently or together with α-amylase to digest starch. Thus, mucosal α-glucosidases can have a synergistic effect with α-amylase on granular starch digestion, consistent with a role in overall starch digestion beyond their primary glucogenesis function.

Mammalian mucosal α-glucosidases coordinate with α-amylase in the initial starch hydrolysis stage to have a role in starch digestion beyond glucogenesis.

Directory of Open Access Journals (Sweden)

Sushil Dhital

Full Text Available Starch digestion in the human body is typically viewed in a sequential manner beginning with α-amylase and followed by α-glucosidase to produce glucose. This report indicates that the two enzyme types can act synergistically to digest granular starch structure. The aim of this study was to investigate how the mucosal α-glucosidases act with α-amylase to digest granular starch. Two types of enzyme extracts, pancreatic and intestinal extracts, were applied. The pancreatic extract containing predominantly α-amylase, and intestinal extract containing a combination of α-amylase and mucosal α-glucosidase activities, were applied to three granular maize starches with different amylose contents in an in vitro system. Relative glucogenesis, released maltooligosaccharide amounts, and structural changes of degraded residues were examined. Pancreatic extract-treated starches showed a hydrolysis limit over the 12 h incubation period with residues having a higher gelatinization temperature than the native starch. α-Amylase combined with the mucosal α-glucosidases in the intestinal extract showed higher glucogenesis as expected, but also higher maltooligosaccharide amounts indicating an overall greater degree of granular starch breakdown. Starch residues after intestinal extract digestion showed more starch fragmentation, higher gelatinization temperature, higher crystallinity (without any change in polymorph, and an increase of intermediate-sized or small-sized fractions of starch molecules, but did not show preferential hydrolysis of either amylose or amylopectin. Direct digestion of granular starch by mammalian recombinant mucosal α-glucosidases was observed which shows that these enzymes may work either independently or together with α-amylase to digest starch. Thus, mucosal α-glucosidases can have a synergistic effect with α-amylase on granular starch digestion, consistent with a role in overall starch digestion beyond their primary

Mammalian Mucosal α-Glucosidases Coordinate with α-Amylase in the Initial Starch Hydrolysis Stage to Have a Role in Starch Digestion beyond Glucogenesis

Science.gov (United States)

Dhital, Sushil; Lin, Amy Hui-Mei; Hamaker, Bruce R.; Gidley, Michael J.; Muniandy, Anbuhkani

2013-01-01

Starch digestion in the human body is typically viewed in a sequential manner beginning with α-amylase and followed by α-glucosidase to produce glucose. This report indicates that the two enzyme types can act synergistically to digest granular starch structure. The aim of this study was to investigate how the mucosal α-glucosidases act with α-amylase to digest granular starch. Two types of enzyme extracts, pancreatic and intestinal extracts, were applied. The pancreatic extract containing predominantly α-amylase, and intestinal extract containing a combination of α-amylase and mucosal α-glucosidase activities, were applied to three granular maize starches with different amylose contents in an in vitro system. Relative glucogenesis, released maltooligosaccharide amounts, and structural changes of degraded residues were examined. Pancreatic extract-treated starches showed a hydrolysis limit over the 12 h incubation period with residues having a higher gelatinization temperature than the native starch. α-Amylase combined with the mucosal α-glucosidases in the intestinal extract showed higher glucogenesis as expected, but also higher maltooligosaccharide amounts indicating an overall greater degree of granular starch breakdown. Starch residues after intestinal extract digestion showed more starch fragmentation, higher gelatinization temperature, higher crystallinity (without any change in polymorph), and an increase of intermediate-sized or small-sized fractions of starch molecules, but did not show preferential hydrolysis of either amylose or amylopectin. Direct digestion of granular starch by mammalian recombinant mucosal α-glucosidases was observed which shows that these enzymes may work either independently or together with α-amylase to digest starch. Thus, mucosal α-glucosidases can have a synergistic effect with α-amylase on granular starch digestion, consistent with a role in overall starch digestion beyond their primary glucogenesis function. PMID

Influence of phosphate esters on the annealing properties of starch

DEFF Research Database (Denmark)

Wischmann, Bente; Muhrbeck, Per

1998-01-01

The effects of annealing on native potato, waxy maize, and phosphorylated waxy maize starches were compared. Phosphorylated waxy maize starch responded to annealing in a manner between that of the naturally phosphorylated potato starch and that of the native waxy maize starch. The gelatinisation...... end-point temperature was increased, whereas in the native waxy maize it was decreased. On the other hand, the onset temperature change was much larger in potato starch than in the two waxy maize starches. Steeping also yielded intermediate effects on the phosphorylated waxy maize starch....... It was concluded that the phosphate groups have similar effects as they do in the native, naturally phosphorylated potato starch, although the substitution pattern is not entirely the same in the artificially phosphorylated starch....

Starch mediated CdS nanoparticles and their photocatalytic performance under visible light irradiation

Energy Technology Data Exchange (ETDEWEB)

Firdaus, Farha, E-mail: Farha-firdaus@yahoo.co.in [Chemistry Section, Women’s College, Aligarh Muslim University, Aligarh 202002 UP (India); Faraz, Mohd [Department of Chemistry, Faculty of Science, Aligarh Muslim University, Aligarh 202002 (India)

2016-05-06

Green synthesis of Cadmium Sulphide (CdS-S) nanoparticles is of considerable interest due to its biocompatible and nontoxicity. Here, we present a biomolecule stimulated chemical method was adopted for the successful synthesis of CdS-S nanoparticles using starch as a capping agent. The CdS-S nanoparticles were characterized by various analytical techniques. The CdS-S nanoparicles exhibit photocatalytic activity against methyl orange (MO) at pH 9 in Visible light and the reaction follows pseudo first-order kinetics. The comparative photocatalytic activity revealed that CdS-S nanoparticles remarkably enhanced activities as compared to the commercial TiO{sub 2} nanoparticles. The outcome of these studies offers valuable for planning CdS-S nanoparticles having photocatalytic activities helpful for the formulation of waste water remediation.

Starch mediated CdS nanoparticles and their photocatalytic performance under visible light irradiation

International Nuclear Information System (INIS)

Firdaus, Farha; Faraz, Mohd

2016-01-01

Green synthesis of Cadmium Sulphide (CdS-S) nanoparticles is of considerable interest due to its biocompatible and nontoxicity. Here, we present a biomolecule stimulated chemical method was adopted for the successful synthesis of CdS-S nanoparticles using starch as a capping agent. The CdS-S nanoparticles were characterized by various analytical techniques. The CdS-S nanoparicles exhibit photocatalytic activity against methyl orange (MO) at pH 9 in Visible light and the reaction follows pseudo first-order kinetics. The comparative photocatalytic activity revealed that CdS-S nanoparticles remarkably enhanced activities as compared to the commercial TiO 2 nanoparticles. The outcome of these studies offers valuable for planning CdS-S nanoparticles having photocatalytic activities helpful for the formulation of waste water remediation.

Rheological properties of concentrated solutions of carboxymethyl starch

Directory of Open Access Journals (Sweden)

Stojanović Željko

2003-01-01

Full Text Available Carboxymethyl starch was synthesized by the esterification of starch with monochloroacetic acid in ethanol as a reaction medium. Three samples of carboxymethyl starch having different degrees of substitution were prepared. The influence of temperature on the viscosity of concentrated carboxymethyl starch solutions, as well as the dynamic-mechanical properties of the concentrated solutions were investigated. The activation energy of viscous flow was determined and it was found that it decreased with increasing degree of substitution. The results of the dynamic-mechanical measurements showed that solutions of starch and carboxymethyl starches with higher degrees of substitution behave as gels. Values of the storage modulus in the rubbery plateau were used to calculate the molar masses between two points of physical crosslinking, the density of crosslinking and the distance between two points of crosslinking.

Mechanochemical degradation of potato starch paste under ultrasonic irradiation

Institute of Scientific and Technical Information of China (English)

LI Jian-bin; LI Lin; LI Bing; CHEN Ling; GUI Lin

2006-01-01

In the paper, changes in the molecular weight, the intrinsic viscosity and the polydispersity (molecular mass distribution) of treated potato starch paste were studied under different ultrasonic conditions which include irradiation time, ultrasonic intensity, potato starch paste concentration, and distance from probe tip on the degradation of potato starch paste. Intrinsic viscosity of potato starch paste was determined following the ASTM (American Society for Testing and Materials) standard practice for dilute solution viscosity of polymers. Molecular mass and polydispersity of potato starch paste were measured on GPC (Gel Permeation Chromatography). The results showed that the average molecular mass and the intrinsic viscosity of starch strongly depended on irradiation time. Degradation increased with prolonged ultrasonic irradiation time, and the increase of ultrasonic intensity could accelerate the degradation, resulting in a faster degradation rate, a lower limiting value and a higher degradation extent. Starch samples were degraded faster in dilute solutions than in concentrated solutions. The molecular mass and the intrinsic viscosity of starch increased with the increase of distance from probe tip. Our results also showed that the polydispersity decreased with ultrasonic irradiation under all ultrasonic conditions. Ultrasonic degradation of potato starch paste occured based on the mechanism of molecular relaxation of starch paste. In the initial stage, ultrasonic degradation of potato starch paste was a random process, and the molecular mass distribution was broad. After that, ultrasonic degradation of potato starch paste changed to a nonrandom process, and the molecular mass distribution became narrower. Finally, molecular mass distribution tended toward a saturation value.

The Importance of the Circadian Clock in Regulating Plant Metabolism

Directory of Open Access Journals (Sweden)

Jin A Kim

2017-12-01

Full Text Available Carbohydrates are the primary energy source for plant development. Plants synthesize sucrose in source organs and transport them to sink organs during plant growth. This metabolism is sensitive to environmental changes in light quantity, quality, and photoperiod. In the daytime, the synthesis of sucrose and starch accumulates, and starch is degraded at nighttime. The circadian clock genes provide plants with information on the daily environmental changes and directly control many developmental processes, which are related to the path of primary metabolites throughout the life cycle. The circadian clock mechanism and processes of metabolism controlled by the circadian rhythm were studied in the model plant Arabidopsis and in the crops potato and rice. However, the translation of molecular mechanisms obtained from studies of model plants to crop plants is still difficult. Crop plants have specific organs such as edible seed and tuber that increase the size or accumulate valuable metabolites by harvestable metabolic components. Human consumers are interested in the regulation and promotion of these agriculturally significant crops. Circadian clock manipulation may suggest various strategies for the increased productivity of food crops through using environmental signal or overcoming environmental stress.

Impact of pressure on physicochemical properties of starch dispersions

KAUST Repository

Yang, Zhi; Chaib, Sahraoui; Gu, Qinfen; Hemar, Yacine

2016-01-01

High hydrostatic pressure (HHP) can be employed as a non-thermal sterilization technique in the food industry while inducing structure and physicochemical changes of the food macromolecules like starch. The effect of HHP on starch depends on various factors including starch type and concentration, pressurization temperature, time, and suspending media. In this review, we summarize the influence of HHP on the structure, gelatinization, retrogradation, and modification of starches from different botanical origins. Suggestions for future research are provided to better understand the mechanism of HHP on starch, and on how HHP can be used in the starch industry. © 2016 Elsevier Ltd.

Impact of pressure on physicochemical properties of starch dispersions

KAUST Repository

Yang, Zhi

2016-09-02

High hydrostatic pressure (HHP) can be employed as a non-thermal sterilization technique in the food industry while inducing structure and physicochemical changes of the food macromolecules like starch. The effect of HHP on starch depends on various factors including starch type and concentration, pressurization temperature, time, and suspending media. In this review, we summarize the influence of HHP on the structure, gelatinization, retrogradation, and modification of starches from different botanical origins. Suggestions for future research are provided to better understand the mechanism of HHP on starch, and on how HHP can be used in the starch industry. © 2016 Elsevier Ltd.

Enzymic conversion of starch to glucose

Energy Technology Data Exchange (ETDEWEB)

1964-08-19

Corn is steeped in a SO/sub 2/ solution for 30 to 40 hours, coarsely ground, separated from the germ, and filtered. A 35% suspension of the germ-free corn, still containing fibers, hull, and gluten, is treated with Ca(OH)/sub 2/ to raise the pH to 6.5 to 7.0. A starch-liquifying enzyme is added and after a 2 hours treatment at 85/sup 0/ the liquefied starch is cooled to 60/sup 0/ and the pH is adjusted to 4.5 to 5.0 with H/sub 2/SO/sub 4/. A saccharifying enzyme is now added. After 40 to 81 hours, a raw glucose solution is obtained and is freed from fibers and gluten by filtration. The commercial starch-liquifying enzymes are designated HT-1000 and Neozyme 3 LC (liquid). The saccharifying enzymes are Diazyme or Diazyme L 30 (liquid). The solid enzymes are used at a level up to 0.1% by weight of the starch. Up to 100% conversion of starch into glucose is achieved.

The regulation of protein synthesis and translation factors by CD3 and CD28 in human primary T lymphocytes

Directory of Open Access Journals (Sweden)

Proud Christopher G

2002-05-01

Full Text Available Abstract Background Activation of human resting T lymphocytes results in an immediate increase in protein synthesis. The increase in protein synthesis after 16–24 h has been linked to the increased protein levels of translation initiation factors. However, the regulation of protein synthesis during the early onset of T cell activation has not been studied in great detail. We studied the regulation of protein synthesis after 1 h of activation using αCD3 antibody to stimulate the T cell receptor and αCD28 antibody to provide the co-stimulus. Results Activation of the T cells with both antibodies led to a sustained increase in the rate of protein synthesis. The activities and/or phosphorylation states of several translation factors were studied during the first hour of stimulation with αCD3 and αCD28 to explore the mechanism underlying the activation of protein synthesis. The initial increase in protein synthesis was accompanied by activation of the guanine nucleotide exchange factor, eukaryotic initiation factor (eIF 2B, and of p70 S6 kinase and by dephosphorylation of eukaryotic elongation factor (eEF 2. Similar signal transduction pathways, as assessed using signal transduction inhibitors, are involved in the regulation of protein synthesis, eIF2B activity and p70 S6 kinase activity. A new finding was that the p38 MAPK α/β pathway was involved in the regulation of overall protein synthesis in primary T cells. Unexpectedly, no changes were detected in the phosphorylation state of the cap-binding protein eIF4E and the eIF4E-binding protein 4E-BP1, or the formation of the cap-binding complex eIF4F. Conclusions Both eIF2B and p70 S6 kinase play important roles in the regulation of protein synthesis during the early onset of T cell activation.

COORDINATION OF CASSAVA STARCH TO METAL IONS AND ...

African Journals Online (AJOL)

a

starch. On the other hand, the decomposition proceeded at a lower rate than the decomposition of ... Metal salts influenced the thermal decomposition of starches [4, 5]. Thus, properly ..... reactions of starch resulting in dextrins. After the ...

Biosysthesis of Corn Starch Palmitate by Lipase Novozym 435

Directory of Open Access Journals (Sweden)

Kai Lin

2012-06-01

Full Text Available Esterification of starch was carried out to expand the usefulness of starch for a myriad of industrial applications. Lipase B from Candida antarctica, immobilized on macroporous acrylic resin (Novozym 435, was used for starch esterification in two reaction systems: micro-solvent system and solvent-free system. The esterification of corn starch with palmitic acid in the solvent-free system and micro-solvent system gave a degree of substitution (DS of 1.04 and 0.0072 respectively. Esterification of corn starch with palmitic acid was confirmed by UV spectroscopy and IR spectroscopy. The results of emulsifying property analysis showed that the starch palmitate with higher DS contributes to the higher emulsifying property (67.6% and emulsion stability (79.6% than the native starch (5.3% and 3.9%. Modified starch obtained by esterification that possesses emulsifying properties and has long chain fatty acids, like palmitic acid, has been widely used in the food, pharmaceutical and biomedical applications industries.

Concerted suppression of all starch branching enzyme genes in barley produces amylose-only starch granules

DEFF Research Database (Denmark)

Carciofi, Massimiliano; Blennow, Andreas; Jensen, Susanne L

2012-01-01

to glucose and rapidly absorbed in the small intestine. But a portion of dietary starch, termed "resistant starch" (RS) escapes digestion and reaches the large intestine, where it is fermented by colonic bacteria producing short chain fatty acids (SCFA) which are linked to several health benefits. The RS...

Development of highly-transparent protein/starch-based bioplastics.

Science.gov (United States)

Gonzalez-Gutierrez, J; Partal, P; Garcia-Morales, M; Gallegos, C

2010-03-01

Striving to achieve cost-competitive biomass-derived materials for the plastics industry, the incorporation of starch (corn and potato) to a base formulation of albumen and glycerol was considered. To study the effects of formulation and processing, albumen/starch-based bioplastics containing 0-30 wt.% starch were prepared by thermo-plastic and thermo-mechanical processing. Transmittance measurements, DSC, DMTA and tensile tests were performed on the resulting bioplastics. Optical and tensile properties were strongly affected by starch concentration. However, DMTA at low deformation proved to be insensitive to starch addition. Thermo-mechanical processing led to transparent albumen/starch materials with values of strength at low deformation comparable to commodity plastics. Consequently, albumen biopolymers may become a biodegradable alternative to oil-derived plastics for manufacturing transparent packaging and other plastic stuffs. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Characterization of chestnut (Castanea sativa, mill starch for industrial utilization

Directory of Open Access Journals (Sweden)

Demiate Ivo Mottin

2001-01-01

Full Text Available Studies were conducted to characterize the chestnut and its starch. Chemical composition of the chestnuts showed high level of starch. Moisture level in the raw nuts was around 50g/100g in wet basis and starch content, around 80g/100g in dry basis; other nut flour components were protein (5.58 g/100g, lipid (5.39 g/100g, crude fiber (2.34 g/100g and ash (2.14 g/100g. Starch fraction was chemically characterized in order to identify the granule quality as compared with those of cassava and corn. This fraction showed more lipids and proteins than the other starches. Chestnut starch granules showed peculiar shape, smaller than the control starches and low amount of damaged units. Chemical composition concerning amylose : amylopectin ratio was intermediate to that presented by cassava and corn starch granules. Water absorption at different temperatures as well as solubility were also intermediate but closer to that presented by cassava granules. The same behavior was observed in the interaction with dimethyl-sulfoxide. Native starch granules and those submitted to enzymatic treatment with commercial alpha-amylase and also with enzymes from germinated wheat were observed by scanning electronic microscopy. Water suspensions of chestnut starch granules were heated to form pastes that were studied comparatively to those obtained with cassava and corn starches. Viscographic pattern of chestnut starch pastes showed a characteristic profile with high initial viscosity but peak absence, high resistance to mechanical stirring under hot conditions and high final viscosity. There was no way to compare it with the paste viscographic profiles obtained with the control starches. Chestnut starch pastes were stable down to pH 4 but unstable at pH 3. The water losses observed in the chestnut starch pastes after freeze-thaw cycles showed more similarity to the pattern observed in corn starch pastes as well as clarity and strength of the gel. In general the results

Crystallinity changes in wheat starch during the bread-making process: Starch crystallinity in the bread crust

NARCIS (Netherlands)

Primo-Martín, C.; Nieuwenhuijzen, N.H. van; Hamer, R.J.; Vliet, T. van

2007-01-01

The crystallinity of starch in crispy bread crust was quantified using several different techniques. Confocal scanning laser microscopy (CSLM) demonstrated the presence of granular starch in the crust and remnants of granules when moving towards the crumb. Differential scanning calorimetry (DSC)

Crystallinity changes in wheat starch during the bread-making process: starch crystallinity in the bread crust

NARCIS (Netherlands)

Primo-Martin, C.; Nieuwenhuijzen, van N.H.; Hamer, R.J.; Vliet, van T.

2007-01-01

The crystallinity of starch in crispy bread crust was quantified using several different techniques. Confocal scanning laser microscopy (CSLM) demonstrated the presence of granular starch in the crust and remnants of granules when moving towards the crumb. Differential scanning calorimetry (DSC)

Structure of potato starch

DEFF Research Database (Denmark)

Bertoft, Eric; Blennow, Andreas

2016-01-01

Potato starch granules consist primarily of two tightly packed polysaccharides, amylose and amylopectin. Amylose, which amount for 20-30%, is the principal linear component, but a fraction is in fact slightly branched. Amylopectin is typically the major component and is extensively branched...... chains extending from the clusters. A range of enzymes is involved in the biosynthesis of the cluster structures and linear segments. These are required for sugar activation, chain elongation, branching, and trimming of the final branching pattern. As an interesting feature, potato amylopectin...... is substituted with low amounts of phosphate groups monoesterified to the C-3 and the C-6 carbons of the glucose units. They seem to align well in the granular structure and have tremendous effects on starch degradation in the potato and functionality of the refined starch. A specific dikinase catalyzes...

The effect of starch amylose content on the morphology andproperties of melt-processed butyl-etherified starch/poly[(butylenesuccinate)-co-adipate] blends

CSIR Research Space (South Africa)

Maubane, Lesego T

2017-01-01

Full Text Available structures. Thermogravimetric analysis revealed that the thermal stability of the blends decreased with increasing starch loading for all starch types with varying amylose content; however, the nature of the starch controlled the mechanical properties...

A comparative study of the physicochemical properties of starches ...

African Journals Online (AJOL)

Some properties of starches from cassava, potato and sweet potato were compared with cereal starches from maize, wheat, millet and sorghum. The aim was to determine the properties of tuber and root crop starches and compare them with cereal starches in addition to unravelling the potential of commonly grown ...

Effect of cellulose reinforcement on the properties of organic acid modified starch microparticles/plasticized starch bio-composite films.

Science.gov (United States)

Teacă, Carmen-Alice; Bodîrlău, Ruxanda; Spiridon, Iuliana

2013-03-01

The present paper describes the preparation and characterization of polysaccharides-based bio-composite films obtained by the incorporation of 10, 20 and 30 wt% birch cellulose (BC) within a glycerol plasticized matrix constituted by the corn starch (S) and chemical modified starch microparticles (MS). The obtained materials (coded as MS/S, respectively MS/S/BC) were further characterized. FTIR spectroscopy and X-ray diffraction were used to evidence structural and crystallinity changes in starch based films. Morphological, thermal, mechanical, and water resistance properties were also investigated. Addition of cellulose alongside modified starch microparticles determined a slightly improvement of the starch-based films water resistance. Some reduction of water uptake for any given time was observed mainly for samples containing 30% BC. Some compatibility occurred between MS and BC fillers, as evidenced by mechanical properties. Tensile strength increased from 5.9 to 15.1 MPa when BC content varied from 0 to 30%, while elongation at break decreased significantly. Copyright © 2012 Elsevier Ltd. All rights reserved.

The future of starch bioengineering: GM microorganisms or GM plants?

Directory of Open Access Journals (Sweden)

Kim Henrik eHebelstrup

2015-04-01

Full Text Available Plant starches regularly require extensive modification to permit subsequent applications. Such processing is usually done by the use of chemical and/or physical treatments. The use of recombinant enzymes produced by large-scale fermentation of GM microorganisms is increasingly used in starch processing and modification, sometimes as an alternative to chemical or physical treatments. However, as a means to impart the modifications as early as possible in the starch production chain, similar recombinant enzymes may also be expressed in planta in the developing starch storage organ such as in roots, tubers and cereal grains to provide a GM crop as an alternative to the use of enzymes from GM microorganisms. We here discuss these techniques in relation to important structural features and modifications of starches such as: starch phosphorylation, starch hydrolysis, chain transfer/branching and novel concepts of hybrid starch-based polysaccharides. In planta starch bioengineering is generally challenged by yield penalties and inefficient production of the desired product. However in some situations, GM crops for starch bioengineering without deleterious effects have been achieved.

1H-13C NMR-based profiling of biotechnological starch utilization

DEFF Research Database (Denmark)

Sundekilde, Ulrik K.; Meier, Sebastian

2016-01-01

Starch is used in food-and non-food applications as a renewable and degradable source of carbon and energy. Insight into the chemical detail of starch degradation remains challenging as the starch constituents amylose and amylopectin are homopolymers. We show that considerable molecular detail...... of starch fragmentation can be obtained from multivariate analysis of spectral features in optimized 1H-13C NMR spectroscopy of starch fragments to identify relevant features that distinguish processes in starch utilization. As a case study, we compare the profiles of starch fragments in commercial beer...... samples. Spectroscopic profiles of homooligomeric starch fragments can be excellent indicators of process conditions. In addition, differences in the structure and composition of starch fragments have predictive value for down-stream process output such as ethanol production from starch. Thus, high...

Application of oxidized starch in bake-only chicken nuggets.

Science.gov (United States)

Purcell, Sarah; Wang, Ya-Jane; Seo, Han-Seok

2014-05-01

There is a need to reduce the fat content in fried foods because of increasing health concerns from consumers. Oxidized starches have been utilized in many coating applications for their adhesion ability. However, it is not known if they perform similarly in bake-only products. This study investigated the application of oxidized starch in bake-only chicken nuggets. Oxidized starches were prepared from 7 starches and analyzed for gelatinization and pasting properties. Chicken nuggets were prepared using batter containing wheat flour, oxidized starch, salt, and leavening agents prior to steaming, oven baking, freezing, and final oven baking for sensory evaluation. All nuggets were analyzed for hardness by a textural analyzer, crispness by an acoustic sound, and sensory characteristics by a trained panel. The oxidation level used in the study did not alter the gelatinization temperature of most starches, but increased the peak pasting viscosity of both types of corn and rice starches and decreased that of tapioca and potato starches. There were slight differences in peak force and acoustic reading between some treatments; however, the differences were not consistent with starch type or amylose content. There was no difference among the treatments as well as between the control with wheat flour and the treatments partially replaced with oxidized starches in all sensory attributes of bake-only nuggets evaluated by the trained panel. There is a need to reduce the fat content in fried food, such as chicken nuggets, because of increasing childhood obesity. Oxidized starches are widely used in coating applications for their adhesion ability. This study investigated the source of oxidized starches in steam-baked coated nuggets for their textural and sensorial properties. The findings from this research will provide an understanding of the contributions of starch source and oxidation to the texture and sensory attributes of bake-only nuggets, and future directions to improve

Engineering potato starch with a higher phosphate content

NARCIS (Netherlands)

Xu, Xuan; Huang, Xing Feng; Visser, Richard G.F.; Trindade, Luisa M.

2017-01-01

Phosphate esters are responsible for valuable and unique functionalities of starch for industrial applications. Also in the cell phosphate esters play a role in starch metabolism, which so far has not been well characterized in storage starch. Laforin, a human enzyme composed of a

Starch-based Foam Composite Materials: processing and bioproducts

Science.gov (United States)

Starch is an abundant, biodegradable, renewable and low-cost commodity that has been explored as a replacement for petroleum-based plastics. By itself, starch is a poor replacement for plastics because of its moisture sensitivity and brittle properties. Efforts to improve starch properties and funct...

Molecular structure, functionality and applications of oxidized starches: A review.

Science.gov (United States)

Vanier, Nathan Levien; El Halal, Shanise Lisie Mello; Dias, Alvaro Renato Guerra; da Rosa Zavareze, Elessandra

2017-04-15

During oxidation, the hydroxyl groups of starch molecules are first oxidized to carbonyl groups, then to carboxyl groups. The contents of the carbonyl and carboxyl groups in a starch molecule therefore indicate the extent of starch oxidation. The mechanisms of starch oxidation with different oxidizing agents, including sodium hypochlorite, hydrogen peroxide, ozone and sodium periodate, are described in this review. The effects of these oxidizing agents on the molecular, physicochemical, thermal, pasting and morphological properties of starch are described as well. In addition, the main industrial applications of oxidized starches are presented. The present review is important for understanding the effects of oxidation on starch properties, and this information may facilitate the development of novel oxidized starches for both food and non-food applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Digestion and Interaction of Starches with α-Amylases: I. Mutational analysis of Carbohydrate Binding Sites in barley. II. In Vitro Starch Digestion of Legumes

DEFF Research Database (Denmark)

Nielsen, Morten Munch

2006-01-01

the hydrolysis of internal 1,4-α-D-glucosidic bonds in starch and related polysaccharides. The present thesis concerns studies of two α-amylases: 1) secondary substrate binding sites in barley α-amylase 1 (AMY1), and 2) the involvement of anti-nutrients in in vitro digestion of starch in legumes by porcine...... in morphology between high amylose starch granules and normal starch granules. Legumes (beans, peas, and lentils) are characterised by low blood glucose raising potential, which is proportional to the in vitro starch digestion rates. The high amount of anti-nutritional factors (phytate, proteinaceous inhibitors......, tannins, and lectins) in legumes has been associated with the slow starch digestion. However, it is still debated in literature to which extent the legume starch digestibility is affected by anti-nutritional factors. The in vitro starch digestion (hydrolytic index, HI) of pea (Pisum sativum) and mixtures...

The future of starch bioengineering: GM microorganisms or GM plants?

DEFF Research Database (Denmark)

Hebelstrup, Kim; Sagnelli, Domenico; Blennow, Andreas

2015-01-01

, tubers and cereal grains to provide a GM crop as an alternative to the use of enzymes from GM microorganisms. We here discuss these techniques in relation to important structural features and modifications of starches such as: starch phosphorylation, starch hydrolysis, chain transfer/branching and novel...... concepts of hybrid starch-based polysaccharides. In planta starch bioengineering is generally challenged by yield penalties and inefficient production of the desired product. However, in some situations, GM crops for starch bioengineering without deleterious effects have been achieved....

Synthesis, Surface Modification and Optical Properties of Thioglycolic Acid-Capped ZnS Quantum Dots for Starch Recognition at Ultralow Concentration

Science.gov (United States)

Tayebi, Mahnoush; Tavakkoli Yaraki, Mohammad; Ahmadieh, Mahnaz; Mogharei, Azadeh; Tahriri, Mohammadreza; Vashaee, Daryoosh; Tayebi, Lobat

2016-11-01

In this research, water-soluble thioglycolic acid-capped ZnS quantum dots (QDs) are synthesized by the chemical precipitation method. The prepared QDs are characterized using x-ray diffraction and transmission electron microscopy. Results revealed that ZnS QDs have a 2.73 nm crystallite size, cubic zinc blende structure, and spherical morphology with a diameter less than 10 nm. Photoluminescence (PL) spectroscopy is performed to determine the presence of low concentrations of starch. Four emission peaks are observed at 348 nm, 387 nm, 422 nm, and 486 nm and their intensities are quenched by increasing concentration of starch. PL intensity variations in the studied concentrations range (0-100 ppm) are best described by a Michaelis-Menten model. The Michaelis constant ( K m) for immobilized α-amylase in this system is about 101.07 ppm. This implies a great tendency for the enzyme to hydrolyze the starch as substrate. Finally, the limit of detection is found to be about 6.64 ppm.

In vitro starch digestion correlates well with rate and extent of starch digestion in broiler chickens

NARCIS (Netherlands)

Weurding, R.E.; Veldman, R.; Veen, W.A.G.; Aar, van der P.J.; Verstegen, M.W.A.

2001-01-01

Current feed evaluation systems for poultry are based on digested components (fat, protein and nitrogen-free extracts). Digestible starch is the most important energy source in broiler chicken feeds and is part of the nitrogen-free extract fraction. Digestible starch may be predicted using an in

Rheological behavior of gamma-irradiated cassava (Manihot esculenta crantz) starch

Energy Technology Data Exchange (ETDEWEB)

Silva, Orelio L.; Uehara, Vanessa B.; Mastro, Nelida L. del, E-mail: nlmastro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

Cassava starch is the by-product of the process of pressing water out of cassava to make cassava meal. The juice has a fine starch, similar to rice or potato starch that, when dried, yields polvilho doce (sweet manioc starch); from the fermented juice comes polvilho azedo (sour manioc starch). Cassava starch can perform most of the functions where maize, rice and wheat starch are currently used. The aim of the present work was to determine the influence or ionizing radiation on the rheological behavior of aqueous preparations of gamma-irradiated cassava starch at different concentrations. Samples of polvilho doce and polvilho azedo were obtained at the local market and irradiated in plastic bags in a Gammacell 220 with doses of 1, 3 e 5 kGy, dose rate ∼ 1.2 kGy h-1. A Brooksfield viscometer was employed for the viscosity measurements. The results showed a strong dependence of the viscosity with the concentration of the starch solutions. In most of the cases there was a decrease of viscosity with the increase of the radiation dose usually seen in irradiated polysaccharides. Nevertheless, the dose response relation of the two kind of starch was different. (author)

Rheological behavior of gamma-irradiated cassava (Manihot esculenta crantz) starch

International Nuclear Information System (INIS)

Silva, Orelio L.; Uehara, Vanessa B.; Mastro, Nelida L. del

2013-01-01

Cassava starch is the by-product of the process of pressing water out of cassava to make cassava meal. The juice has a fine starch, similar to rice or potato starch that, when dried, yields polvilho doce (sweet manioc starch); from the fermented juice comes polvilho azedo (sour manioc starch). Cassava starch can perform most of the functions where maize, rice and wheat starch are currently used. The aim of the present work was to determine the influence or ionizing radiation on the rheological behavior of aqueous preparations of gamma-irradiated cassava starch at different concentrations. Samples of polvilho doce and polvilho azedo were obtained at the local market and irradiated in plastic bags in a Gammacell 220 with doses of 1, 3 e 5 kGy, dose rate ∼ 1.2 kGy h-1. A Brooksfield viscometer was employed for the viscosity measurements. The results showed a strong dependence of the viscosity with the concentration of the starch solutions. In most of the cases there was a decrease of viscosity with the increase of the radiation dose usually seen in irradiated polysaccharides. Nevertheless, the dose response relation of the two kind of starch was different. (author)

Phosphorylation of mouse serine racemase regulates D-serine synthesis

DEFF Research Database (Denmark)

Foltyn, Veronika N; Zehl, Martin; Dikopoltsev, Elena

2010-01-01

Serine racemase (SR) catalyses the synthesis of the transmitter/neuromodulator D-serine, which plays a major role in synaptic plasticity and N-methyl D-aspartate receptor neurotoxicity. We now report that SR is phosphorylated at Thr71 and Thr227 as revealed by mass spectrometric analysis and in v...... with a phosphorylation-deficient SR mutant indicate that Thr71 phosphorylation increases SR activity, suggesting a novel mechanism for regulating D-serine production....

Molecular evolution of the endosperm starch synthesis pathway genes in rice (Oryza sativa L.) and its wild ancestor, O. rufipogon L.

Science.gov (United States)

Yu, Guoqin; Olsen, Kenneth M; Schaal, Barbara A

2011-01-01

The evolution of metabolic pathways is a fundamental but poorly understood aspect of evolutionary change. One approach for understanding the complexity of pathway evolution is to examine the molecular evolution of genes that together comprise an integrated metabolic pathway. The rice endosperm starch biosynthetic pathway is one of the most thoroughly characterized metabolic pathways in plants, and starch is a trait that has evolved in response to strong selection during rice domestication. In this study, we have examined six key genes (AGPL2, AGPS2b, SSIIa, SBEIIb, GBSSI, ISA1) in the rice endosperm starch biosynthesis pathway to investigate the evolution of these genes before and after rice domestication. Genome-wide sequence tagged sites data were used as a neutral reference to overcome the problems of detecting selection in species with complex demographic histories such as rice. Five variety groups of Oryza sativa (aus, indica, tropical japonica, temperate japonica, aromatic) and its wild ancestor (O. rufipogon) were sampled. Our results showed evidence of purifying selection at AGPL2 in O. rufipogon and strong evidence of positive selection at GBSSI in temperate japonica and tropical japonica varieties and at GBSSI and SBEIIb in aromatic varieties. All the other genes showed a pattern consistent with neutral evolution in both cultivated rice and its wild ancestor. These results indicate the important role of positive selection in the evolution of starch genes during rice domestication. We discuss the role of SBEIIb and GBSSI in the evolution of starch quality during rice domestication and the power and limitation of detecting selection using genome-wide data as a neutral reference.

Transcriptome wide identification and characterization of starch branching enzyme in finger millet.

Science.gov (United States)

Tyagi, Rajhans; Tiwari, Apoorv; Garg, Vijay Kumar; Gupta, Sanjay

2017-01-01

Starch-branching enzymes (SBEs) are one of the four major enzyme classes involved in starch biosynthesis in plants and play an important role in determining the structure and physical properties of starch granules. Multiple SBEs are involved in starch biosynthesis in plants. Finger millet is calcium rich important serial crop belongs to grass family and the transcriptome data of developing spikes is available on NCBI. In this study it was try to find out the gene sequence of starch branching enzyme and annotate the sequence and submit the sequence for further use. Rice SBE sequence was taken as reference and for characterization of the sequence different in silico tools were used. Four domains were found in the finger millet Starch branching enzyme like alpha amylase catalytic domain from 925 to2172 with E value 0, N-terminal Early set domain from 634 to 915 with E value 1.62 e-42, Alpha amylase, C-terminal all-beta domain from 2224 to 2511 with E value 5.80e-24 and 1,4-alpha-glucan-branching enzyme from 421 to 2517 with E value 0. Major binding interactions with the GLC (alpha-d-glucose), CA (calcium ion), GOL (glycerol), TRS (2-amino-2-hydroxymethylpropane- 1, 3-diol), MG (magnesium ion) and FLC (citrate anion) are fond with different residues. It was found in the phylogenetic study of the finger millet SBE with the 6 species of grass family that two clusters were form A and B. In cluster A, finger millet showed closeness with Oryzasativa and Setariaitalica, Sorghum bicolour and Zea mays while cluster B was formed with Triticumaestivum and Brachypodium distachyon. The nucleotide sequence of Finger millet SBE was submitted to NCBI with the accession no KY648913 and protein structure of SBE of finger millet was also submitted in PMDB with the PMDB id - PM0080938. This research presents a comparative overview of Finger millet SBE and includes their properties, structural and functional characteristics, and recent developments on their post-translational regulation.

Synthesis of a novel superdisintegrant by starch derivatization with polysuccinimide and its application for the development of Ondansetron fast dissolving tablet.

Science.gov (United States)

Sadeghi, Mozhgan; Hemmati, Salar; Hamishehkar, Hamed

2016-01-01

Disintegrants are the key excipients administered in tablet formulations to boost the decomposition of the tablet into smaller pieces in the gastrointestinal environment, thereby increasing the available surface area and enhancing a more rapid release of the active ingredient. Polysuccinimide (PSI), a biodegradable polymer synthesized from aspartic acid, was reacted with starch and fully assessed by CHN, (1)H-NMR, and FTIR. PSI-grafted starch (PSI-St) was synthesized and applied as a disintegrant in the formulation of a rapidly disintegrating tablet of Ondansetron, a nausea and vomiting medicine. The tablet formulated with the newly developed superdisintegrant was evaluated for hardness, friability, disintegration time, and dissolution rate, and the results were compared with tablets formulated with an identical composition of test formulation differing only in type of disintegrant. Tablets prepared with starch and tablets prepared with sodium starch glycolate (SSG) were used as negative and positive controls, respectively. Dissolution study results indicated that although the onset of disintegration action was faster for SSG than PSI-St, higher amounts of drug were released from tablets formulated from PSI-St than from those formulated from SSG during 10 min. It was concluded that the novel synthesized superdisintegrant has an appropriate potential for the application in the formulation of fast dissolving tablets.

Mechanical Properties of Potato- Starch Linear Low Density ...

African Journals Online (AJOL)

The mechanical properties of potato-starch filled LLDPE such as Young's Modulus, tensile strength and elongation at break were studied. Apart from the Young's Modulus, the tensile strength and elongation at break reduced with increased starch content. This is attributed to poor adhesion between starch and the polymer ...

Composition and Physicochemical Properties of Starch from Christ ...

African Journals Online (AJOL)

Starch was extracted from seeds of Christ Thorn by hot water extraction method. The composition and physicochemical properties of the extracted starch were determined using standard methods. The results obtained from the analyses revealed that the % yield of starch was 43.2%, while moisture content, ash content, ...

Isolation and Characterization of Starches from eight Dioscorea ...

African Journals Online (AJOL)

AJB SERVER

2006-09-04

Sep 4, 2006 ... temperature, with Moonshine (895.551 ± 1.051%) having the highest swelling power ... The properties of the different Dioscorea alata starches may prove useful in nutritional applications. ..... coating. Starch/Starke 44: 393-398. Ayensu ES, Coursey DG (1972). ... World production and marketing of starch. In:.

Resistant starch: an indigestible fraction of foods

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Saura Calixto, F.

1991-06-01

Full Text Available Resistant starch (RS, the dietary starch that scape digestion in the small intestine, can yields up to 20% of the starch in cereal and legume products. Several fractions contribute to the total RS of foods: retrograded amylose, starch inaccessible to digestive enzymes because of mechanical barriers, chemically modified starch fragments, undigested starch due to α-amylase inhibitors and starch complexed with other food components. RS is formed in products processed following heat treatments (baking, extrusion, autoclaving, etc.. RS produces significant fecal bulking and is partially fermentable by anaerobic bacteria of the colon. On the other hand, the relation of resistant starch with the glucose and insulin response in human subjects is an important nutritional effect. RS analytical methods are reported.

El almidón resistente (RS, fracción de almidón de la dieta que no es digerido en el intestino delgado, puede alcanzar hasta un 20% del almidón en productos derivados de cereales y legumbres. Varias fracciones contribuyen al contenido total de almidón resistente: amilosa retrogradada, almidón inaccesible físicamente a los enzimas digestivos, almidón indigestible debido a inhibición de α-amilasas y almidón complejado con otros constituyentes de los alimentos. El almidón resistente se forma en productos que han sufrido tratamientos térmicos (panificación, extrusión, autoclave, etc. El RS aumenta el volumen de heces y es fermentado parcialmente en el colon por bacterias anaeróbicas. Igualmente, está relacionado con los niveles de glucosa en sangre y la respuesta de insulina en humanos. Se describen los métodos analíticos para su determinación.

Influence of starch origin on rheological properties of concentrated aqueous solutions

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Stojanović Željko P.

2011-01-01

Full Text Available The rheological properties of corn and potato starch concentrated aqueous solutions were investigated at 25ºC. The starches were previously dispersed in water and the solutions were obtained by heating of dispersions at 115-120ºC for 20 minutes. The solutions of potato starch were transparent, while the corn starch solutions were opalescent. The results of dynamic mechanical measurements showed that the values of viscosity, h, storage modulus, G′, and loss modulus, G″, of the corn starch solutions increased with the storage time. This phenomenon was not observed for the potato starch solutions. It was assumed that the increase of h, G′ and G″ is the result of starch solutions retrogradation. The potato starch solutions retrogradation did not occur probably because of the phosphates presence. The viscosity of 2 mass % corn starch solution is less than the viscosity of 2 mass % potato starch solution. By increasing the concentration of corn starch solution the gel with elastic behavior was formed. The corn starch solutions formed gel as early as at 4 mass % concentration, while potato starch solutions achieved the gel state at the concentration of 5 mass %. The value of exponent m (G′ and G″ µ wm during the transition of potato starch solutions to gel is 0.414, which gives the fractal dimensions for corn starch of 2.10. The obtained value of fractal dimension corresponds to slow aggregation. The corn starch solutions with the starch concentrations higher than 4 mass % form weak gels. For these solutions the values of modulus in rubber plateau were determined. It was found that the modulus in rubber plateau increased with the concentration by the exponent of 4.36. Such high exponent value was obtained in the case when the tridimensional network is formed, i.e. when supermolecular structures like associates or crystal domains are formed.

Morphological and mechanical properties of thermoplastic starch (TPS) and its blend with poly(lactic acid)(PLA) using cassava bagasse and starch

International Nuclear Information System (INIS)

Teixeira, Eliangela de M.; Correa, Ana C.; Campos, Adriana de; Marconcini, Jose M.; Mattoso, Luiz H.C.; Curvelo, Antonio A.S.

2011-01-01

This study aims the use of an agro waste coming from the industrialization of cassava starch, known as cassava bagasse (BG). This material contains residual starch and cellulose fibers which can be used to obtain thermoplastic starch (TPS) and /or blends reinforced with fibers. In this context, it was prepared a thermoplastic starch with BG (TPSBG) and evaluated the incorporation of 20wt% of it into the biodegradable polymer poly (lactic acid) (PLA), resulting in a blend PLA/TPSBG20. The materials were investigated through morphology (scanning electron microscopy with field emission gun (FEG), x-ray diffraction (XRD), and mechanical behavior (tensile test). Their properties were compared to the blend PLA/TPSI20 in which TPSI is obtained from commercial cassava starch. The results showed that the use of bagasse generates homogenous materials with higher mechanical strength if compared to TPS obtained from commercial cassava starch. The fiber in this residue acted as reinforcement for TPS and PLA/TPS systems. (author)

Transcription factor ART1 mediates starch hydrolysis and mycotoxin production in Fusarium graminearum and F. verticillioides.

Science.gov (United States)

Oh, Mira; Son, Hokyoung; Choi, Gyung Ja; Lee, Chanhui; Kim, Jin-Cheol; Kim, Hun; Lee, Yin-Won

2016-06-01

Molecular mechanisms underlying the responses to environmental factors, such as nitrogen, carbon and pH, involve components that regulate the production of secondary metabolites, including mycotoxins. In this study, we identified and characterized a gene in the FGSG_02083 locus, designated as FgArt1, which was predicted to encode a Zn(II)2 Cys6 zinc finger transcription factor. An FgArt1 deletion mutant of Fusarium graminearum exhibited impaired starch hydrolysis as a result of significantly reduced α-amylase gene expression. The deletion strain was unable to produce trichothecenes and exhibited low Tri5 and Tri6 expression levels, whereas the complemented strain showed a similar ability to produce trichothecenes as the wild-type strain. In addition, FgArt1 deletion resulted in impairment of germination in starch liquid medium and reduced pathogenicity on flowering wheat heads. To investigate the roles of the FgArt1 homologue in F. verticillioides, we deleted the FVEG_02083 gene, and the resulting strain showed defects in starch hydrolysis, similar to the FgArt1 deletion strain, and produced no detectable level of fumonisin B1 . Fum1 and Fum12 expression levels were undetectable in the deletion strain. However, when the FvArt1-deleted F. verticillioides strain was complemented with FgArt1, the resulting strain was unable to recover the production of fumonisin B1 , although FgArt1 expression and starch hydrolysis were induced. Thus, our results suggest that there are different regulatory pathways governed by each ART1 transcription factor in trichothecene and fumonisin biosynthesis. Taken together, we suggest that ART1 plays an important role in both trichothecene and fumonisin biosynthesis by the regulation of genes involved in starch hydrolysis. © 2015 BSPP AND JOHN WILEY & SONS LTD.

Investigating the phase transformations in starch during gelatinisation

International Nuclear Information System (INIS)

Tan, I.; Sopade, P.A.; Halley, P.J.

2003-01-01

Full text: Starch, a natural polymer of amylose and amylopectin, continues to be a prime material for biodegradable plastic applications as well as many food and non-food uses. Raw starch exists as semicrystalline granules with complex internal supramolecular packing and can be hierarchically organised on four length scales: molecular scale (∼ Angstroms), lamellar structure (∼90 Angstroms); growth rings (∼ 0.1 μm) and the whole granule morphology (∼μm). Starch can be converted into thermoplastic material (TPS) through destructurisation in the presence of plasticisers under specific extrusion conditions. During the transformation of granular starch into TPS, the complex granular supramolecular structure gives rise to the characteristic endothermic first order transition known as gelatinization. Despite advances in research on starch gelatinisation, the precise structural change and transitions involved are still a matter of debate. Moreover, structural variables such as botanical origins, amylose/amylopectin ratio, macromolecular sizes, etc, have been known to influence the physicochemical properties of starch and the transitions it undergoes.While understanding the linkage between structural characteristics and gelatinisation behaviour will provide fundamental knowledge that is critical for the development of next-generation starch biodegradable plastics, this has proved difficult mainly due to poor knowledge of the exact mechanism involved in gelatinisation. This is further complicated by the sketchy idea on the role of structure and organisation of the starch granule. Studies in our laboratory on four types of maize starches with different amylose/amylopectin ratio revealed that although there is a general trend on the variation of gelatinisation parameters with plasticisers concentration, the extent of the variation are different for different types of starch. It was also found that these differences are not a directly related to the variation in

Partial characterization of chayotextle starch-based films added with ascorbic acid encapsulated in resistant starch.

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Martínez-Ortiz, Miguel A; Vargas-Torres, Apolonio; Román-Gutiérrez, Alma D; Chavarría-Hernández, Norberto; Zamudio-Flores, Paul B; Meza-Nieto, Martín; Palma-Rodríguez, Heidi M

2017-05-01

Chayotextle starch was modified by subjecting it to a dual treatment with acid and heating-cooling cycles. This caused a decrease in the content of amylose, which showed values of 30.22%, 4.80%, 3.27% and 3.57% for native chayotextle starch (NCS), starch modified by acid hydrolysis (CMS), and CMS with one (CMS1AC) and three autoclave cycles (CMS3AC), respectively. The percentage of crystallinity showed an increase of 36.9%-62% for NCS and CMS3AC. The highest content of resistant starch (RS) was observed in CMS3AC (37.05%). The microcapsules were made with CMS3AC due to its higher RS content; the total content of ascorbic acid of the microcapsules was 82.3%. The addition of different concentrations of CMS3AC microcapsules (0%, 2.5%, 6.255% and 12.5%) to chayotextle starch-based films (CSF) increased their tensile strength and elastic modulus. The content of ascorbic acid and RS in CSF was ranged from 0% to 59.4% and from 4.84% to 37.05% in the control film and in the film mixed with CMS3AC microcapsules, respectively. Water vapor permeability (WVP) values decreased with increasing concentrations of microcapsules in the films. Microscopy observations showed that higher concentrations of microcapsules caused agglomerations due their poor distribution in the matrix of the films. Copyright © 2017 Elsevier B.V. All rights reserved.

Films based on oxidized starch and cellulose from barley.

Science.gov (United States)

El Halal, Shanise Lisie Mello; Colussi, Rosana; Deon, Vinícius Gonçalves; Pinto, Vânia Zanella; Villanova, Franciene Almeida; Carreño, Neftali Lenin Villarreal; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

2015-11-20

Starch and cellulose fibers were isolated from grains and the husk from barley, respectively. Biodegradable films of native starch or oxidized starches and glycerol with different concentrations of cellulose fibers (0%, 10% and 20%) were prepared. The films were characterized by morphological, mechanical, barrier, and thermal properties. Cellulose fibers isolated from the barley husk were obtained with 75% purity and high crystallinity. The morphology of the films of the oxidized starches, regardless of the fiber addition, was more homogeneous as compared to the film of the native starch. The addition of cellulose fibers in the films increased the tensile strength and decreased elongation. The water vapor permeability of the film of oxidized starch with 20% of cellulose fibers was lower than the without fibers. However the films with cellulose fibers had the highest decomposition with the initial temperature and thermal stability. The oxidized starch and cellulose fibers from barley have a good potential for use in packaging. The addition of cellulose fibers in starch films can contribute to the development of films more resistant that can be applied in food systems to maintain its integrity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bluetongue virus non-structural protein 1 is a positive regulator of viral protein synthesis

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Boyce Mark

2012-08-01

Full Text Available Abstract Background Bluetongue virus (BTV is a double-stranded RNA (dsRNA virus of the Reoviridae family, which encodes its genes in ten linear dsRNA segments. BTV mRNAs are synthesised by the viral RNA-dependent RNA polymerase (RdRp as exact plus sense copies of the genome segments. Infection of mammalian cells with BTV rapidly replaces cellular protein synthesis with viral protein synthesis, but the regulation of viral gene expression in the Orbivirus genus has not been investigated. Results Using an mRNA reporter system based on genome segment 10 of BTV fused with GFP we identify the protein characteristic of this genus, non-structural protein 1 (NS1 as sufficient to upregulate translation. The wider applicability of this phenomenon among the viral genes is demonstrated using the untranslated regions (UTRs of BTV genome segments flanking the quantifiable Renilla luciferase ORF in chimeric mRNAs. The UTRs of viral mRNAs are shown to be determinants of the amount of protein synthesised, with the pre-expression of NS1 increasing the quantity in each case. The increased expression induced by pre-expression of NS1 is confirmed in virus infected cells by generating a replicating virus which expresses the reporter fused with genome segment 10, using reverse genetics. Moreover, NS1-mediated upregulation of expression is restricted to mRNAs which lack the cellular 3′ poly(A sequence identifying the 3′ end as a necessary determinant in specifically increasing the translation of viral mRNA in the presence of cellular mRNA. Conclusions NS1 is identified as a positive regulator of viral protein synthesis. We propose a model of translational regulation where NS1 upregulates the synthesis of viral proteins, including itself, and creates a positive feedback loop of NS1 expression, which rapidly increases the expression of all the viral proteins. The efficient translation of viral reporter mRNAs among cellular mRNAs can account for the observed

Bluetongue virus non-structural protein 1 is a positive regulator of viral protein synthesis.

Science.gov (United States)

Boyce, Mark; Celma, Cristina C P; Roy, Polly

2012-08-29

Bluetongue virus (BTV) is a double-stranded RNA (dsRNA) virus of the Reoviridae family, which encodes its genes in ten linear dsRNA segments. BTV mRNAs are synthesised by the viral RNA-dependent RNA polymerase (RdRp) as exact plus sense copies of the genome segments. Infection of mammalian cells with BTV rapidly replaces cellular protein synthesis with viral protein synthesis, but the regulation of viral gene expression in the Orbivirus genus has not been investigated. Using an mRNA reporter system based on genome segment 10 of BTV fused with GFP we identify the protein characteristic of this genus, non-structural protein 1 (NS1) as sufficient to upregulate translation. The wider applicability of this phenomenon among the viral genes is demonstrated using the untranslated regions (UTRs) of BTV genome segments flanking the quantifiable Renilla luciferase ORF in chimeric mRNAs. The UTRs of viral mRNAs are shown to be determinants of the amount of protein synthesised, with the pre-expression of NS1 increasing the quantity in each case. The increased expression induced by pre-expression of NS1 is confirmed in virus infected cells by generating a replicating virus which expresses the reporter fused with genome segment 10, using reverse genetics. Moreover, NS1-mediated upregulation of expression is restricted to mRNAs which lack the cellular 3' poly(A) sequence identifying the 3' end as a necessary determinant in specifically increasing the translation of viral mRNA in the presence of cellular mRNA. NS1 is identified as a positive regulator of viral protein synthesis. We propose a model of translational regulation where NS1 upregulates the synthesis of viral proteins, including itself, and creates a positive feedback loop of NS1 expression, which rapidly increases the expression of all the viral proteins. The efficient translation of viral reporter mRNAs among cellular mRNAs can account for the observed replacement of cellular protein synthesis with viral protein

Preparation and Properties of Cassava Starch-based Wood Adhesives

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Qing Xu

2016-06-01

Full Text Available A biodegradable, environmentally friendly starch-based wood adhesive with cassava starch as a raw material and butyl acrylate (BA as a co-monomer was synthesized. Results revealed that this cassava starch-based wood adhesive (SWA was more stable than corn starch-based wood adhesive, and its bonding performance was close to that of commercial PVAc emulsion, even after 90 days of storage. Further analysis found that the improved stability of the adhesive could be attributed to its low minimum film forming temperature (MFFT and glass transition temperature (Tg of cassava starch. Moreover, the amount of total volatile organic compounds (TVOCs emitted by the cassava starch-based wood adhesive were much lower than the Chinese national standard control criteria. Therefore, cassava SWA might be a potential alternative to traditional petrochemical-based wood adhesives.

Preparation and Characterization of Some Polyethylene Modified- Starch Biodegradable Films

International Nuclear Information System (INIS)

Badrana, A.S.; Ramadanb, A.M.; Ibrahim, N.A.; Kahild, T.; Hussienc, H.A.

2005-01-01

Blends of LDPE with soluble starch, wheat flour and commercial starch were prepared by mixing starch (or flour) with styrene then blending the mixture with LDPE, The starch percents vary between 5 and 50% of the total weight. Their physical and mechanical properties were recorded and compared with pure LDPE. It was observed that the increase in starch or wheat flour contents of the mixture was reversibly proportional to the tensile strength and % elongation. Samples were tested for water absorption. All of the samples were insoluble in cold and boiling water. Moisture uptake increased with immersion time and increasing starch content. The changes in the tensile strength of LDPE/starch (or wheat flour) after the course of thermal oxidation was measured. These results show negligible changes in the tensile strength of the control sample as compared to that of the samples containing the additives. Oxidation processes take advantage of the high temperatures (40-50 degree C) and the time. It was also observed that after 10 weeks of soil burial, the mechanical properties of the films decrease, mainly, due to starch removal from the films. Also, for the weight loss a drastic decrease was observed after 10 weeks of soil burial thereafter it preceded slowly. The LDPE/ starch strips showed weight loss after treating with a-amylase this due to hydrolysis and leaching of the starch. The rate of starch hydrolysis increases with the increase in starch content of the sample. The influence of addition of starch on the overall migration of these films, with different food simulant, was studied, at different temperatures (-4 degree. 25 degree and 40 degree C). All values were significantly lower than the upper limit for overall migration set by the EU (10 mg/dirf) for food grade plastics packaging materials

SNPs in genes functional in starch-sugar interconversion associate with natural variation of tuber starch and sugar content of potato (Solanum tuberosum L.).

Science.gov (United States)

Schreiber, Lena; Nader-Nieto, Anna Camila; Schönhals, Elske Maria; Walkemeier, Birgit; Gebhardt, Christiane

2014-07-31

Starch accumulation and breakdown are vital processes in plant storage organs such as seeds, roots, and tubers. In tubers of potato (Solanum tuberosum L.) a small fraction of starch is converted into the reducing sugars glucose and fructose. Reducing sugars accumulate in response to cold temperatures. Even small quantities of reducing sugars affect negatively the quality of processed products such as chips and French fries. Tuber starch and sugar content are inversely correlated complex traits that are controlled by multiple genetic and environmental factors. Based on in silico annotation of the potato genome sequence, 123 loci are involved in starch-sugar interconversion, approximately half of which have been previously cloned and characterized. By means of candidate gene association mapping, we identified single-nucleotide polymorphisms (SNPs) in eight genes known to have key functions in starch-sugar interconversion, which were diagnostic for increased tuber starch and/or decreased sugar content and vice versa. Most positive or negative effects of SNPs on tuber-reducing sugar content were reproducible in two different collections of potato cultivars. The diagnostic SNP markers are useful for breeding applications. An allele of the plastidic starch phosphorylase PHO1a associated with increased tuber starch content was cloned as full-length cDNA and characterized. The PHO1a-HA allele has several amino acid changes, one of which is unique among all known starch/glycogen phosphorylases. This mutation might cause reduced enzyme activity due to impaired formation of the active dimers, thereby limiting starch breakdown. Copyright © 2014 Schreiber et al.

Adaptation to the digestion of nutrients of a starch diet or a non-starch polysaccharide diet in group-housed pregnant sows

NARCIS (Netherlands)

Peet-Schwering, van der C.M.C.; Kemp, B.; Hartog, den L.A.; Schrama, J.W.; Verstegen, M.W.A.

2002-01-01

A trial was conducted with twenty group-housed pregnant sows to study the adaptation in nutrient digestibility to a starch-rich diet or a diet with a high level of fermentable non-starch polysaccharides (NSP) during a time period of 6 weeks. The starch-rich diet was primarily composed of wheat, peas

Comparison of ambient solvent extraction methods for the analysis of fatty acids in non-starch lipids of flour and starch

Science.gov (United States)

Bahrami, Niloufar; Yonekura, Lina; Linforth, Robert; Carvalho da Silva, Margarida; Hill, Sandra; Penson, Simon; Chope, Gemma; Fisk, Ian Denis

2014-01-01

BACKGROUND Lipids are minor components of flours, but are major determinants of baking properties and end-product quality. To the best of our knowledge, there is no single solvent system currently known that efficiently extracts all non-starch lipids from all flours without the risk of chemical, mechanical or thermal damage. This paper compares nine ambient solvent systems (monophasic and biphasic) with varying polarities: Bligh and Dyer (BD); modified Bligh and Dyer using HCl (BDHCL); modified BD using NaCl (BDNaCl); methanol–chloroform–hexane (3:2:1, v/v); Hara and Radin (hexane–isopropanol, 3:2, v/v); water-saturated n-butanol; chloroform; methanol and hexane for their ability to extract total non-starch lipids (separated by lipid classes) from wheat flour (Triticum aestivum L.). Seven ambient extraction protocols were further compared for their ability to extract total non-starch lipids from three alternative samples: barley flour (Hordeum vulgare L.), maize starch (Zea mays L.) and tapioca starch (Manihot esculenta Crantz). RESULTS For wheat flour the original BD method and those containing HCl or NaCl tended to extract the maximum lipid and a significant correlation between lipid extraction yield (especially the glycolipids and phospholipids) and the polarity of the solvent was observed. For the wider range of samples BD and BD HCl repeatedly offered the maximum extraction yield and using pooled standardized (by sample) data from all flours, total non-starch lipid extraction yield was positively correlated with solvent polarity (r = 0.5682, P starches when compared to the flour samples, which is due to the differences in lipid profiles between the two sample types (flours and starches). PMID:24132804

Dielectric spectroscopy of Ag-starch nanocomposite films

Science.gov (United States)

Meena; Sharma, Annu

2018-04-01

In the present work Ag-starch nanocomposite films were fabricated via chemical reduction route. The formation of Ag nanoparticles was confirmed using transmission electron microscopy (TEM). Further the effect of varying concentration of Ag nanoparticles on the dielectric properties of starch has been studied. The frequency response of dielectric constant (ε‧), dielectric loss (ε″) and dissipation factor tan(δ) has been studied in the frequency range of 100 Hz to 1 MHz. Dielectric data was further analysed using Cole-Cole plots. The dielectric constant of starch was found to be 4.4 which decreased to 2.35 in Ag-starch nanocomposite film containing 0.50 wt% of Ag nanoparticles. Such nanocomposites with low dielectric constant have potential applications in microelectronic technologies.

Amino acid metabolism in dairy cows and their regulation in milk synthesis.

Science.gov (United States)

Wang, Feiran; Shi, Haitao; Wang, Shuxiang; Wang, Yajing; Cao, Zhijun; Li, Shengli

2018-06-10

Reducing dietary crude protein (CP) and supplementing with certain amino acids (AAs) has been known as a potential solution to improve nitrogen (N) efficiency in dairy production. Thus understanding how AAs are utilized in various sites along the gut is critical. AA flow from the intestine to portal-drained viscera (PDV) and liver then to the mammary gland was elaborated in this article. Recoveries in individual AA in PDV and liver seem to share similar AA pattern with input: output ratio in mammary gland, which subdivides essential AA (EAA) into two groups, lysine (Lys) and branched-chain AA (BCAA) in group 1, input: output ratio > 1; methionine (Met), histidine (His), phenylalanine (Phe) etc. in group 2, input: output ratio close to 1. AAs in the mammary gland are either utilized for milk protein synthesis or retained as body tissue, or catabolized. The fractional removal of AAs and the number and activity of AA transporters together contribute to the ability of AAs going through mammary cells. Mammalian target of rapamycin (mTOR) pathway is closely related to milk protein synthesis and provides alternatives for AA regulation of milk protein synthesis, which connects AA with lactose synthesis via α-lactalbumin (gene: LALBA) and links with milk fat synthesis via sterol regulatory element-binding transcription protein 1 (SREBP1) and peroxisome proliferator-activated receptor (PPAR). Overall, AA flow across various tissues reveal AA metabolism and utilization in dairy cows on one hand. While the function of AA in the biosynthesis of milk protein, fat and lactose at both transcriptional and posttranscriptional level from another angle provides the possibility for us to regulate them for higher efficiency. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Effect of Ultrasound on Physicochemical Properties of Wheat Starch

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Mahsa Majzoobi

2014-04-01

Full Text Available Application of ultrasound process is growing in food industry for different purposes including homogenization, extraction, blanching and removal of microorganisms, etc. On the other hand, starch is a natural polymer which exists in many foods or added into the food as an additive. Therefore, determination of the effects of ultrasound on starch characteristics can be useful in interpretation of the properties of starch-containing products. The main aim of this study was to determine the physicochemical changes of wheat starch treated by ultrasound waves. Therefore, an ultrasound probe device was used which ran at 20 kHz, 100 W and 22°C. Starch suspension in distilled water (30% w/w was prepared and treated with ultrasound for 5, 10, 15 and 20 min. The results showed that increases in processing duration led to increases in water solubility of starch, water absorption and gel clarity (as determined by spectrophotometry. Starch intrinsic viscosity as measured using an Ostwald U-tube showed lower intrinsic viscosity with increases in ultrasound time. Gel strength of the samples as determined using a texture analyzer was reduced by longer processing time. The scanning electron microscopy revealed that increasing the duration time of the ultrasound treatment could produce some cracks and spots on the surface of the granules. In total, it was concluded that the ultrasound treatment resulted in some changes from the starch granular scale to molecular levels. Some of the starch molecules were degraded upon ultrasound processing. Such changes may be observed for the starch-containing foods treated with ultrasound and they are enhanced with increases in ultrasound time intervals.

Supply of avocado starch (Persea americana mill) as bioplastic material

Science.gov (United States)

Ginting, M. H. S.; Hasibuan, R.; Lubis, M.; Alanjani, F.; Winoto, F. A.; Siregar, R. C.

2018-02-01

The purpose of this study was to determine the effect of time precipitation of avocado slurry seed to yield of starch. Starch analysis included starch content, moisture content, amylose content, amylopectin content, ash content, protein content, fat content, Fourier transform infra red analysis and rapid visco analyzer. Supply of starch from avocado seeds was used by extraction method. Every one hundred grams of avocado slurry was precipitated by gravity with variations for 4 hours, 8 hours, 12 hours, 16 hours, 20 hours and 24 hours. The Starch yield was washed, and dried using oven at 70°C for 30 minutes. Starch yield was the highest as 24.20 gram at 24 hours. The result of starch characterization was 73.62%, water content 16.6%, amylose 0.07%, amylopectin 73.55%, ash content 0.23%, protein content 2.16%, fat content 1.09%. Rapid visco analyzer obtained at 91.33°C of gelatinization temperature. Scanning electron microscopy analyzes obtained 20 μm oval-shaped starch granules. Fourier Transform Infra Red analysis of starch obtained the peak spectrum of O-H group of alcohols, C-H alkanes and C-O ether.

Thermal treatment of starch slurry in Couette-Taylor flow apparatus

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Hubacz Robert

2017-09-01

Full Text Available In this paper, thermal processing of starch slurry in a Couette-Taylor flow (CTF apparatus was investigated. Gelatinized starch dispersion, after treatment in the CTF apparatus, was characterized using such parameters like starch granule diameters (or average diameter, starch granule swelling degree (quantifying the amount of water absorbed by starch granules and concentration of dissolved starch. These parameters were affected mostly by the process temperature, although the impact of the axial flow or rotor rotation on them was also observed. Moreover, the analysis of results showed a relatively good correlation between these parameters, as well as, between those parameter and apparent viscosity of gelatinized starch dispersion. Meanwhile, the increase in the value of the apparent viscosity and in shear-tinning behaviour of dispersion was associated with the progress of starch processing in the CTF apparatus. Finally, the CTF apparatuses of different geometries were compared using numerical simulation of the process. The results of the simulation indicated that the apparatus scaling-up without increasing the width of the gap between cylinders results in higher mechanical energy consumption per unit of processed starch slurry.

Swelling Kinetics of Waxy Maize Starch

Science.gov (United States)

Desam, Gnana Prasuna Reddy

Starch pasting behavior greatly influences the texture of a variety of food products such as canned soup, sauces, baby foods, batter mixes etc. The annual consumption of starch in the U.S. is 3 million metric tons. It is important to characterize the relationship between the structure, composition and architecture of the starch granules with its pasting behavior in order to arrive at a rational methodology to design modified starch of desirable digestion rate and texture. In this research, polymer solution theory was applied to predict the evolution of average granule size of starch at different heating temperatures in terms of its molecular weight, second virial coefficient and extent of cross-link. Evolution of granule size distribution of waxy native maize starch when subjected to heating at constant temperatures of 65, 70, 75, 80, 85 and 90 C was characterized using static laser light scattering. As expected, granule swelling was more pronounced at higher temperatures and resulted in a shift of granule size distribution to larger sizes with a corresponding increase in the average size by 100 to 120% from 13 mum to 25-28 mum. Most of the swelling occurred within the first 10 min of heating. Pasting behavior of waxy maize at different temperatures was also characterized from the measurements of G' and G" for different heating times. G' was found to increase with temperature at holding time of 2 min followed by its decrease at larger holding times. This behavior is believed to be due to the predominant effect of swelling at small times. However, G" was insensitive to temperature and holding times. The structure of waxy maize starch was characterized by cryoscanning electron microscopy. Experimental data of average granule size vs time at different temperatures were compared with model predictions. Also the Experimental data of particle size distribution vs particle size at different times and temperatures were compared with model predictions.

Degradation of corn starch under the influence of gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

El Saadany, R M.A.; El Saadany, F M; Foda, Y H

1976-01-01

Irradiation of corn (maize) starch with different doses of gamma irradiation ranging from 1 x 10/sup 5/ rad to 1 x 10/sup 6/ rad resulted in the increase of starch acidity and reducing power. Molecular degradation was observed as a result of marked decrease in starch viscosity and intinsic viscosity as well as swelling capacity. The gelatinization time and temperature of the irradiated starch became shorter than in the control sample. Internal changes in the irradiated starch occured as a result of lowering the number of glucose unit per segment in the irradiated starch molecules. All changes were proportional to the doses of gamma irradiation used.

Degradation of corn starch under the influence of gamma irradiation

International Nuclear Information System (INIS)

El Saadany, R.M.A.; El Saadany, F.M.; Foda, Y.H.

1976-01-01

Irradiation of corn (maize) starch with different doses of gamma irradiation ranging from 1 x 10 5 rad to 1 x 10 6 rad resulted in the increase of starch acidity and reducing power. Molecular degradation was observed as a result of marked decrease in starch viscosity and intinsic viscosity as well as swelling capacity. The gelatinization time and temperature of the irradiated starch became shorter than in the control sample. Internal changes in the irradiated starch occured as a result of lowering the number of glucose unit per segment in the irradiated starch molecules. All changes were proportional to the doses of gamma irradiation used. (orig.) [de

Starch digestibility and predicted glycemic index of fried sweet potato cultivars

Directory of Open Access Journals (Sweden)

Amaka Odenigbo

2012-07-01

Full Text Available Background: Sweet potato (Ipomoea batatas L. is a very rich source of starch. There is increased interest in starch digestibility and the prevention and management of metabolic diseases.Objective: The aim of this study was to evaluate the levels of starch fractions and predicted glycemic index of different cultivars of sweet potato. Material and Method: French fries produced from five cultivars of sweet potato (‘Ginseng Red’, ‘Beauregard’, ‘White Travis’, ‘Georgia Jet clone #2010’ and ‘Georgia Jet’ were used. The level of total starch (TS, resistant starch (RS, digestible starch (DS, and starch digestion index starch digestion index in the samples were evaluated. In vitro starch hydrolysis at 30, 90, and 120 min were determined enzymatically for calculation of rapidly digestible starch (RDS, predicted glycemic index (pGI and slowly digestible starch (SDS respectively. Results: The RS content in all samples had an inversely significant correlation with pGI (-0.52; P<0.05 while RDS had positive and significant influence on both pGI (r=0.55; P<0.05 and SDI (r= 0.94; P<0.01. ‘White Travis’ and ‘Ginseng Red’ had higher levels of beneficial starch fractions (RS and SDS with low pGI and starch digestion Index (SDI, despite their higher TS content. Generally, all the cultivars had products with low to moderate GI values. Conclusion: The glycemic index of these food products highlights the health promoting characteristics of sweet potato cultivars.

Effect of ionizing radiation on starch and cellulose

International Nuclear Information System (INIS)

Klenha, J.; Bockova, J.

1973-09-01

The investigation is reported of the effects of ionizing radiation both on macromolecular systems generally and on polysaccharides, starch and cellulose. Attention is focused on changes in the physical and physico-chemical properties of starch and cellulose, such as starch swelling, gelation, viscosity, solubility, reaction with iodine, UV, IR and ESR spectra, chemical changes resulting from radiolysis and from the effect of amylases on irradiated starch, changes in cellulose fibre strength, water absorption, stain affinity, and also the degradation of cellulose by radiation and the effect of cellulases on irradiated cellulose. Practical applications of the findings concerning cellulose degradation are discussed. (author)

Transglycosylated Starch Modulates the Gut Microbiome and Expression of Genes Related to Lipid Synthesis in Liver and Adipose Tissue of Pigs

Directory of Open Access Journals (Sweden)

Monica A. Newman

2018-02-01

Full Text Available Dietary inclusion of resistant starches can promote host health through modulation of the gastrointestinal microbiota, short-chain fatty acid (SCFA profiles, and lipid metabolism. This study investigated the impact of a transglycosylated cornstarch (TGS on gastric, ileal, cecal, proximal-colonic, and mid-colonic bacterial community profiles and fermentation metabolites using a growing pig model. It additionally evaluated the effect of TGS on the expression of host genes related to glucose and SCFA absorption, incretins, and satiety in the gut as well as host genes related to lipid metabolism in hepatic and adipose tissue. Sixteen growing pigs (4 months of age were fed either a TGS or control (CON diet for 11 days. Bacterial profiles were determined via Illumina MiSeq sequencing of the V3–5 region of the 16S rRNA gene, whereas SCFA and gene expression were measured using gas chromatography and reverse transcription-quantitative PCR. Megasphaera, which was increased at all gut sites, began to benefit from TGS feeding in gastric digesta, likely through cross-feeding with other microbes, such as Lactobacillus. Shifts in the bacterial profiles from dietary TGS consumption in the cecum, proximal colon, and mid colon were similar. Relative abundances of Ruminococcus and unclassified Ruminococcaceae genus were lower, whereas that of unclassified Veillonellaceae genus was higher in TGS- compared to CON-fed pigs (p < 0.05. TGS consumption also increased (p < 0.05 concentrations of SCFA, especially propionate, and lactate in the distal hindgut compared to the CON diet which might have up-regulated GLP1 expression in the cecum (p < 0.05 and mid colon compared to the control diet (p < 0.10. TGS-fed pigs showed increased hepatic and decreased adipocyte expression of genes for lipid synthesis (FASN, SREBP1, and ACACA compared to CON-fed pigs, which may be related to postprandial portal nutrient flow and reduced systemic insulin signaling. Overall, our data

Characterization of Lentinus edodes β-glucan influencing the in vitro starch digestibility of wheat starch gel.

Science.gov (United States)

Zhuang, Haining; Chen, Zhongqiu; Feng, Tao; Yang, Yan; Zhang, Jingsong; Liu, Guodong; Li, Zhaofeng; Ye, Ran

2017-06-01

Lentinus edodes β-glucan (abbreviated LEBG) was prepared from fruiting bodies of Lentinus edodes. The average molecular weight (Mw) and polydispersity index (Mw/Mn) of LEBG were measured to be 1.868×10 6 g/mol and 1.007, respectively. In addition, the monosaccharide composition of LEBG was composed of arabinose, galactose, glucose, xylose, mannose with a molar ratio of 5:11:18:644:16. After adding LEBG, both G' and G″ of starch gel increased. This is mainly because the connecting points between the molecular chains of LEBG and starch formed so that gel network structures were enhanced. The peak temperature in the heat flow diagram shifted to a higher temperature and the peak area of the endothermic enthalpy increased. Furthermore, LEBG can significantly inhibit starch hydrolysis. The predicted glycemic index (pGI) values were reduced when starch was replaced with LEBG at 20% (w/w). It might indicate that LEBG was suitable to develop low GI noodle or bread. Copyright © 2016 Elsevier Ltd. All rights reserved.

Structure, morphology and functionality of acetylated and oxidised barley starches.

Science.gov (United States)

El Halal, Shanise Lisie Mello; Colussi, Rosana; Pinto, Vânia Zanella; Bartz, Josiane; Radunz, Marjana; Carreño, Neftali Lenin Villarreal; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

2015-02-01

Acetylation and oxidation are chemical modifications which alter the properties of starch. The degree of modification of acetylated and oxidized starches is dependent on the catalyst and active chlorine concentrations, respectively. The objective of this study was to evaluate the effect of acetylation and oxidation on the structural, morphological, physical-chemical, thermal and pasting properties of barley starch. Barley starches were acetylated at different catalyst levels (11%, 17%, and 23% of NaOH solution) and oxidized at different sodium hypochlorite concentrations (1.0%, 1.5%, and 2.0% of active chlorine). Fourier-transformed infrared spectroscopy (FTIR), X-ray diffractograms, thermal, morphological, and pasting properties, swelling power and solubility of starches were evaluated. The degree of substitution (DS) of the acetylated starches increased with the rise in catalyst concentration. The percentage of carbonyl (CO) and carboxyl (COOH) groups in oxidized starches also increased with the rise of active chlorine level. The presence of hydrophobic acetyl groups, carbonyl and carboxyl groups caused a partial disorganization and depolymerization of starch granules. The structural, morphological and functional changes in acetylated and oxidized starches varied according to reaction conditions. Acetylation makes barley starch more hydrophobic by the insertion of acetyl groups. Also the oxidation promotes low retrogradation and viscosity. All these characteristics are important for biodegradable film production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Regulation of Carbon Flow by Nitrogen and Light in the Red Alga, Gelidium coulteri.

Science.gov (United States)

Macler, B A

1986-09-01

The red alga Gelidium coulteri Harv. photosynthetically fixed [(14)C] bicarbonate at high rates under defined conditions in unialgal laboratory culture. The fixation rate and flow of photosynthate into various end products were dependent on the nitrogen status of the tissue. Plants fed luxury levels of nitrogen (approximately 340 micromolar) showed fixation rates several-fold higher than those seen for plants starved for nitrogen. The addition of NO(3) (-) or NH(4) (+) to such starved plants further inhibited fixation over at least the first several hours after addition. The majority of (14)C after incubations of 30 minutes to 8 hours was found in the compounds floridoside, agar and floridean starch. In addition, amino acids and intermediate compounds of the reductive pentose phosphate pathway, glycolytic pathway and tricarboxylic acid cycle were detected. Nitrogen affected the partitioning of labeled carbon into these compounds. Plants under luxury nitrogen conditions had higher floridoside levels and markedly lower amounts of agar and starch than found in plants limited for nitrogen. Amino acid, phycobiliprotein and chlorophyll levels were also significantly higher in nitrogen-enriched plants. Addition of NO(3) (-) to starved plants led to an increase in floridoside, tricarboxylic acid cycle intermediates and amino acids within 1 hour and inhibited carbon flow into agar and starch. Carbon fixation in the dark was only 1 to 7% of that seen in the light. Dark fixation of [(14)C]bicarbonate yielded label primarily in tricarboxylic acid cycle intermediates, amino acids and polysaccharides. Nitrogen stimulated amino acid synthesis at the expense of agar and starch. Floridoside was only a minor component in the dark. Pulse-chase experiments, designed to show carbon turnover, indicated a 2-fold increase in labeling of agar over 96 hours of chase in the light. No increases were seen in the dark. Low molecular weight pools, including floridoside, decreased 2- to 5-fold

Reduction of starch granule size by expression of an engineered tandem starch-binding domain in potato plants

NARCIS (Netherlands)

Ji, Q.; Oomen, R.J.F.J.; Vincken, J.P.; Bolam, D.N.; Gilbert, H.J.; Suurs, L.C.J.M.; Visser, R.G.F.

2004-01-01

Granule size is an important parameter when using starch in industrial applications. An artificial tandem repeat of a family 20 starch-binding domain (SBD2) was engineered by two copies of the SBD derived from Bacillus circulans cyclodextrin glycosyltransferase via the Pro-Thr-rich linker peptice

Starch hydrolysis modeling: application to fuel ethanol production.

Science.gov (United States)

Murthy, Ganti S; Johnston, David B; Rausch, Kent D; Tumbleson, M E; Singh, Vijay

2011-09-01

Efficiency of the starch hydrolysis in the dry grind corn process is a determining factor for overall conversion of starch to ethanol. A model, based on a molecular approach, was developed to simulate structure and hydrolysis of starch. Starch structure was modeled based on a cluster model of amylopectin. Enzymatic hydrolysis of amylose and amylopectin was modeled using a Monte Carlo simulation method. The model included the effects of process variables such as temperature, pH, enzyme activity and enzyme dose. Pure starches from wet milled waxy and high-amylose corn hybrids and ground yellow dent corn were hydrolyzed to validate the model. Standard deviations in the model predictions for glucose concentration and DE values after saccharification were less than ± 0.15% (w/v) and ± 0.35%, respectively. Correlation coefficients for model predictions and experimental values were 0.60 and 0.91 for liquefaction and 0.84 and 0.71 for saccharification of amylose and amylopectin, respectively. Model predictions for glucose (R2 = 0.69-0.79) and DP4+ (R2 = 0.8-0.68) were more accurate than the maltotriose and maltose for hydrolysis of high-amylose and waxy corn starch. For yellow dent corn, simulation predictions for glucose were accurate (R2 > 0.73) indicating that the model can be used to predict the glucose concentrations during starch hydrolysis.

AMPD2 Regulates GTP Synthesis and is Mutated in a Potentially-Treatable Neurodegenerative Brainstem Disorder

Science.gov (United States)

Akizu, Naiara; Cantagrel, Vincent; Schroth, Jana; Cai, Na; Vaux, Keith; McCloskey, Douglas; Naviaux, Robert K.; Vleet, Jeremy Van; Fenstermaker, Ali G.; Silhavy, Jennifer L.; Scheliga, Judith S.; Toyama, Keiko; Morisaki, Hiroko; Sonmez, Fatma Mujgan; Celep, Figen; Oraby, Azza; Zaki, Maha S.; Al-Baradie, Raidah; Faqeih, Eissa; Saleh, Mohammad; Spencer, Emily; Rosti, Rasim Ozgur; Scott, Eric; Nickerson, Elizabeth; Gabriel, Stacey; Morisaki, Takayuki; Holmes, Edward W.; Gleeson, Joseph G.

2013-01-01

Purine biosynthesis and metabolism, conserved in all living organisms, is essential for cellular energy homeostasis and nucleic acids synthesis. The de novo synthesis of purine precursors is under tight negative feedback regulation mediated by adenosine and guanine nucleotides. We describe a new distinct early-onset neurodegenerative condition resulting from mutations in the adenosine monophosphate deaminase 2 gene (AMPD2). Patients have characteristic brain imaging features of pontocerebellar hypoplasia (PCH), due to loss of brainstem and cerebellar parenchyma. We found that AMPD2 plays an evolutionary conserved role in the maintenance of cellular guanine nucleotide pools by regulating the feedback inhibition of adenosine derivatives on de novo purine synthesis. AMPD2 deficiency results in defective GTP-dependent initiation of protein translation, which can be rescued by administration of purine precursors. These data suggest AMPD2-related PCH as a new, potentially treatable early-onset neurodegenerative disease. PMID:23911318

Radiolysis of starch

International Nuclear Information System (INIS)

Raffi, J.; Saint-Lebe, L.; Berger, G.

1978-01-01

In the first part of the paper the results of work on the identification and determination of the gamma ( 60 Co) radiolysis products of maize starch are brought together and, wherever possible, a balance drawn up by chemical class. The second part of the paper deals with the main parameters governing radiolysis: dose, irradiation temperature and atmosphere, water content and the conditions under which the irradiated starch is stored. The third part, devoted to the mechanisms believed to be involved, contains the following conclusions: (a) the formation of radiation-induced products with a carbon skeleton probably results from a breaking of the -C-O-C- chains with rearrangement of the radicals and/or a reaction involving the water and the oxygen - the oxygen has an activating effect which does not fundamentally modify the mechanism, whereas the effect of the water is more complex and varies according to the product; (b) the formation of hydrogen peroxide probably implies the addition of atmospheric oxygen to the radiation-induced hydrogen atoms in the water or to the organic radicals obtained by abstraction of a hydrogen from the starch. Lastly, the different methods envisaged for confirming or improving the mechanistic hypotheses are discussed. (author)

Zonation of heme synthesis enzymes in mouse liver and their regulation by β-catenin and Ha-ras.

Science.gov (United States)

Braeuning, Albert; Schwarz, Michael

2010-11-01

Cytochrome P450 (CYP) hemoproteins play an important role in hepatic biotransformation. Recently, β-catenin and Ha-ras signaling have been identified as players controlling transcription of various CYP genes in mouse liver. The aim of the present study was to analyze the role of β-catenin and Ha-ras in the regulation of heme synthesis. Heme synthesis-related gene expression was analyzed in normal liver, in transgenic mice expressing activated β-catenin or Ha-ras, and in hepatomas. Regulation of the aminolevulinate dehydratase promoter was studied in vitro. Elevated expression of mRNAs and proteins involved in heme biosynthesis was linked to β-catenin activation in perivenous hepatocytes, in transgenic hepatocytes, and in hepatocellular tumors. Stimulation of the aminolevulinate dehydratase promoter by β-catenin was independent of the β-catenin/T-cell-specific transcription factor dimer. By contrast, activation of Ha-ras repressed heme synthesis-related gene expression. The present data suggest that β-catenin enhances the expression of both CYPs and heme synthesis-related genes, thus coordinating the availability of CYP apoprotein and its prosthetic group heme. The reciprocal regulation of heme synthesis by β-catenin and Ha-ras-dependent signaling supports our previous hypothesis that antagonistic action of these pathways plays a major role in the control of zonal gene expression in healthy mouse liver and aberrant expression patterns in hepatocellular tumors.

Fragrant starch-based films with limonene

Directory of Open Access Journals (Sweden)

Adrian K. Antosik

2017-02-01

Full Text Available Novel fragrant starch-based films with limonene were successfully prepared. Biodegradable materials of natural origin were used and the process was relatively simple and inexpensive. The effect of limonene on physicochemical properties of starch-based films (moisture absorption, solubility in water, wettability, mechanical properties were compared to glycerol plasticized system. Taking into consideration that the obtained materials could also exhibit bactericidal and fungicidal properties, the studies with Escherichia coli, Candida albicans and Aspergillus niger were performed. Such a material could potentially find application in food packaging (e.g. masking unpleasant odors, hydrophilic starch film would prevent food drying, or in agriculture (e.g. for seed encapsulated tapes.

The oxidation of the aldehyde groups in dialdehyde starch

NARCIS (Netherlands)

Haaksman, I.K.; Besemer, A.C.; Jetten, J.M.; Timmermans, J.W.; Slaghek, T.M.

2006-01-01

This paper describes the difference in relative reactivity of the aldehyde groups present in dialdehyde starch towards different oxidising agents. The oxidation of dialdehyde starch with peracetic acid and sodium bromide leads to only partial oxidation to give mono-aldehyde-carboxy starch, while

Production of amorphous starch powders by solution spray drying

NARCIS (Netherlands)

Niazi, Muhammad B. K.; Broekhuis, Antonius A.

2012-01-01

The spray drying of starch/maltodextrin formulations was evaluated as a potential technology for the manufacturing of amorphous thermoplastic starches. Mixtures of starches with high to low amylose (Am)amylopectin (Ap) ratios were spray-dried from water-based solutions and granular dispersions. The

Saccharide-based Approach to Green Metallic Nanostructure Synthesis

DEFF Research Database (Denmark)

Engelbrekt, Christian; Sørensen, Karsten Holm; Jensen, Palle Skovhus

A green approach to solution synthesis of metallic nanoparticles has been developed using harmless and bioapplicable chemicals as well as moderate temperatures. Metal precursors are reduced by glucose/buffers and sterically stabilized by starch. The saccharide based procedure is highly diverse pr...... producing specifically a wide range of spherical, anisotropic, metallic, semi - conductor and core-shell nanostructures....

Production of modified starches by gamma irradiation

International Nuclear Information System (INIS)

Kang, Il-Jun; Byun, Myung-Woo; Yook, Hong-Sun; Bae, Chun-Ho; Lee, Hyun-Soo; Kwon, Joong-Ho; Chung, Cha-Kwon

1999-01-01

As a new processing method for the production of modified starch, gamma irradiation and four kinds of inorganic peroxides were applied to commercial corn starch. The addition of inorganic peroxides without gamma irradiation or gamma irradiation without the addition of inorganic peroxides effectively decreased initial viscosity, but did not sufficiently keep viscosity stable. The combination of adding ammonium persulfate (APS) and gamma irradiation showed the lowest initial viscosity and the best stability out of the tested four kinds of inorganic peroxides. Among the tested mixing methods of APS, soaking was found to be more effective than dry blending or spraying. Therefore, the production of modified starch with low viscosity as well as with sufficient viscosity stability became feasible by the control of gamma irradiation dose levels and the amount of added APS to starch

Characterization of starch-based bioplastics from jackfruit seed plasticized with glycerol.

Science.gov (United States)

Santana, Renata Ferreira; Bonomo, Renata Cristina Ferreira; Gandolfi, Olga Reinert Ramos; Rodrigues, Luciano Brito; Santos, Leandro Soares; Dos Santos Pires, Ana Clarissa; de Oliveira, Cristiane Patrícia; da Costa Ilhéu Fontan, Rafael; Veloso, Cristiane Martins

2018-01-01

Biodegradable films based on starches from different botanical sources exhibited physicochemical and functional properties which were related with the starch characteristics. However, had inadequate mechanical properties and were hard and brittle. In this research, jackfruit seed starch plasticized with glycerol were developed and characterized. The starch and glycerol concentrations ranged from 2 to 6% w/w and 20 to 60 g/100 g starch, respectively. Bioplastics were obtained by the casting method and characterized in terms of color, mechanical properties, solubility, water vapor permeability ( WVP ), morphology and free energy of the hydrophobic interaction. Electronic micrographics showed the presence of some intact starch granules. The bioplastics were hydrophilic and those of 6% starch and 40% glycerol were the most hydrophilic ([Formula: see text] = 41.35 mJ m -1 ). The solubility of the films presented a direct relationship with the starch concentration ranging from 16.42 to 23.26%. Increased opacity and color difference were observed with increasing starch concentration. The WVP ranged from 1.374 × 10 -3 to 3.07 × 10 -4  g m/day m 2 which was positively related with the concentration of starch and glycerol. Tensile strength, percent elongation and Young's Modulus indicated that the jackfruit starch and glycerol provided a film with good mechanical properties. The results replaced that jackfruit starch can be used to develop films, with low opacity, moderate WVP and relatively high mechanical stability, by using glycerol in the gelatinized starch dispersions.

Phosphorylated alpha(1 leads to 4) glucans as substrate for potato starch-branching enzyme I

International Nuclear Information System (INIS)

Vikso-Nielsen, A.; Blennow, A.; Nielsen, T.H.; Moller, B.L.

1998-01-01

The possible involvement of potato (Solanum tuberosum L.) starch-branching enzyme I (PSBE-I) in the in vivo synthesis of phosphorylated amylopectin was investigated in in vitro experiments with isolated PSBE-I using 33P-labeled phosphorylated and 3H end-labeled nonphosphorylated alpha(1 leads to 4) glucans as the substrates. From these radiolabeled substrates PSBE-I was shown to catalyze the formation of dual-labeled (3H/33P) phosphorylated branched polysaccharides with an average degree of polymerization of 80 to 85. The relatively high molecular mass indicated that the product was the result of multiple chain-transfer reactions. The presence of alpha(1 leads to 6) branch points was documented by isoamylase treatment and anion-exchange chromatography. Although the initial steps of the in vivo mechanism responsible for phosphorylation of potato starch remains elusive, the present study demonstrates that the enzyme machinery available in potato has the ability to incorporate phosphorylated alpha(1 leads to 4) glucans into neutral polysaccharides in an interchain catalytic reaction. Potato mini tubers synthesized phosphorylated starch from exogenously supplied 33PO4(3-) and [U-14C]Glc at rates 4 times higher than those previously obtained using tubers from fully grown potato plants. This system was more reproducible compared with soil-grown tubers and was therefore used for preparation of 33P-labeled phosphorylated alpha(1 leads to 4) glucan chains

Preparation and characterization of starch-based loose-fill packaging foams

Science.gov (United States)

Fang, Qi

Regular and waxy corn starches were blended in various ratios with biodegradable polymers including polylactic acid (PLA), Eastar Bio Copolyester 14766 (EBC) and Mater-Bi ZF03U (MBI) and extruded with a C. W. Brabender laboratory twin screw extruder using a 3-mm die nozzle at 150°C and 150 rev/min. Physical characteristics including radial expansion, unit density and bulk density and water solubility index, water absorption characteristics, mechanical properties including compressibility, Young's modulus, spring index, bulk compressibility and bulk spring index and abrasion resistance were investigated as affected by the ingredient formulations, i.e. type of polymers, type of starches, polymer to starch ratio and starch moisture content. A completely randomized factorial blocking experimental design was used. Fifty-four treatments resulted. Each treatment was replicated three times. SAS statistical software package was used to analyze the data. Foams made of waxy starch had better radial expansion, lower unit density and bulk density than did foams made of regular starch. Regular starch foams had significantly lower water solubility index than did the waxy starch foams. PLA-starch foams had the lowest compressibility and Young's modulus. MBI-starch foams were the most rigid. All foams had excellent spring indices and bulk spring indices which were comparable to the spring index of commercial expanded polystyrene foam. Correlations were established between the foam mechanical properties and the physical characteristics. Foam compressibility and Young's modulus decreased as increases in radial expansion and decreases in unit and bulk densities. Their relationships were modeled with power law equations. No correlation was observed between spring index and bulk spring index and foam physical characteristics. MBI-starch foams had the highest equilibrium moisture content. EBC-starch and PLA-starch foams had similar water absorption characteristics. No significant

Kinetics of starch digestion and performance of broiler chickens

NARCIS (Netherlands)

Weurding, R.E.

2002-01-01

Keywords: starch, digestion rate, broiler chickens, peas, tapioca