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Sample records for starch biosynthesis lead

  1. 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.

  2. 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

  3. 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

  4. 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

  5. OsbZIP58, a basic leucine zipper transcription factor, regulates starch biosynthesis in rice endosperm.

    Science.gov (United States)

    Wang, Jie-Chen; Xu, Heng; Zhu, Ying; Liu, Qiao-Quan; Cai, Xiu-Ling

    2013-08-01

    Starch composition and the amount in endosperm, both of which contribute dramatically to seed yield, cooking quality, and taste in cereals, are determined by a series of complex biochemical reactions. However, the mechanism regulating starch biosynthesis in cereal seeds is not well understood. This study showed that OsbZIP58, a bZIP transcription factor, is a key transcriptional regulator controlling starch synthesis in rice endosperm. OsbZIP58 was expressed mainly in endosperm during active starch synthesis. osbzip58 null mutants displayed abnormal seed morphology with altered starch accumulation in the white belly region and decreased amounts of total starch and amylose. Moreover, osbzip58 had a higher proportion of short chains and a lower proportion of intermediate chains of amylopectin. Furthermore, OsbZIP58 was shown to bind directly to the promoters of six starch-synthesizing genes, OsAGPL3, Wx, OsSSIIa, SBE1, OsBEIIb, and ISA2, and to regulate their expression. These findings indicate that OsbZIP58 functions as a key regulator of starch synthesis in rice seeds and provide new insights into seed quality control.

  6. Dynamic development of starch granules and the regulation of starch biosynthesis in Brachypodium distachyon: comparison with common wheat and Aegilops peregrina.

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    Chen, Guanxing; Zhu, Jiantang; Zhou, Jianwen; Subburaj, Saminathan; Zhang, Ming; Han, Caixia; Hao, Pengchao; Li, Xiaohui; Yan, Yueming

    2014-08-06

    Thorough understanding of seed starch biosynthesis and accumulation mechanisms is of great importance for agriculture and crop improvement strategies. We conducted the first comprehensive study of the dynamic development of starch granules and the regulation of starch biosynthesis in Brachypodium distachyon and compared the findings with those reported for common wheat (Chinese Spring, CS) and Aegilops peregrina. Only B-granules were identified in Brachypodium Bd21, and the shape variation and development of starch granules were similar in the B-granules of CS and Bd21. Phylogenetic analysis showed that most of the Bd21 starch synthesis-related genes were more similar to those in wheat than in rice. Early expression of key genes in Bd21 starch biosynthesis mediate starch synthesis in the pericarp; intermediate-stage expression increases the number and size of starch granules. In contrast, these enzymes in CS and Ae. peregrina were mostly expressed at intermediate stages, driving production of new B-granules and increasing the granule size, respectively. Immunogold labeling showed that granule-bound starch synthase (GBSSI; related to amylose synthesis) was mainly present in starch granules: at lower levels in the B-granules of Bd21 than in CS. Furthermore, GBSSI was phosphorylated at threonine 183 and tyrosine 185 in the starch synthase catalytic domain in CS and Ae. peregrina, but neither site was phosphorylated in Bd21, suggesting GBSSI phosphorylation could improve amylose biosynthesis. Bd21 contains only B-granules, and the expression of key genes in the three studied genera is consistent with the dynamic development of starch granules. GBSSI is present in greater amounts in the B-granules of CS than in Bd21; two phosphorylation sites (Thr183 and Tyr185) were found in Triticum and Aegilops; these sites were not phosphorylated in Bd21. GBSSI phosphorylation may reflect its importance in amylose synthesis.

  7. Overlapping functions of the starch synthases SSII and SSIII in amylopectin biosynthesis in Arabidopsis

    Directory of Open Access Journals (Sweden)

    D'Hulst Christophe

    2008-09-01

    Full Text Available Abstract Background The biochemical mechanisms that determine the molecular architecture of amylopectin are central in plant biology because they allow long-term storage of reduced carbon. Amylopectin structure imparts the ability to form semi-crystalline starch granules, which in turn provides its glucose storage function. The enzymatic steps of amylopectin biosynthesis resemble those of the soluble polymer glycogen, however, the reasons for amylopectin's architectural distinctions are not clearly understood. The multiplicity of starch biosynthetic enzymes conserved in plants likely is involved. For example, amylopectin chain elongation in plants involves five conserved classes of starch synthase (SS, whereas glycogen biosynthesis typically requires only one class of glycogen synthase. Results Null mutations were characterized in AtSS2, which codes for SSII, and mutant lines were compared to lines lacking SSIII and to an Atss2, Atss3 double mutant. Loss of SSII did not affect growth rate or starch quantity, but caused increased amylose/amylopectin ratio, increased total amylose, and deficiency in amylopectin chains with degree of polymerization (DP 12 to DP28. In contrast, loss of both SSII and SSIII caused slower plant growth and dramatically reduced starch content. Extreme deficiency in DP12 to DP28 chains occurred in the double mutant, far more severe than the summed changes in SSII- or SSIII-deficient plants lacking only one of the two enzymes. Conclusion SSII and SSIII have partially redundant functions in determination of amylopectin structure, and these roles cannot be substituted by any other conserved SS, specifically SSI, GBSSI, or SSIV. Even though SSIII is not required for the normal abundance of glucan chains of DP12 to DP18, the enzyme clearly is capable of functioning in production such chains. The role of SSIII in producing these chains cannot be detected simply by analysis of an individual mutation. Competition between

  8. The biosynthesis, structure and gelatinization properties of starches from wild and cultivated African rice species (Oryza barthii and Oryza glaberrima).

    Science.gov (United States)

    Wang, Kai; Wambugu, Peterson W; Zhang, Bin; Wu, Alex Chi; Henry, Robert J; Gilbert, Robert G

    2015-09-20

    The molecular structure and gelatinization properties of starches from domesticated African rice (Oryza glaberrima) and its wild progenitor (Oryza barthii) are determined and comparison made with Asian domesticated rice (Oryza sativa), the commonest commercial rice. This suggests possible enzymatic processes contributing to the unique traits of the African varieties. These have similar starch structures, including smaller amylose molecules, but larger amounts of amylose chains across the whole amylose chain-length distribution, and higher amylose contents, than O. sativa. They also show a higher proportion of two- and three-lamellae spanning amylopectin branch chains (degree of polymerization 34-100) than O. sativa, which contributes to their higher gelatinization temperatures. Fitting amylopectin chain-length distribution with a biosynthesis-based mathematical model suggests that the reason for this difference might be because O. glaberrima and O. barthii have more active SSIIIa and/or less active SBEIIb enzymes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Effect of high temperature on grain filling period, yield, amylose content and activity of starch biosynthesis enzymes in endosperm of basmati rice.

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    Ahmed, Nisar; Tetlow, Ian J; Nawaz, Sehar; Iqbal, Ahsan; Mubin, Muhammad; Nawaz ul Rehman, Muhammad Shah; Butt, Aisha; Lightfoot, David A; Maekawa, Masahiko

    2015-08-30

    High temperature during grain filling affects yield, starch amylose content and activity of starch biosynthesis enzymes in basmati rice. To investigate the physiological mechanisms underpinning the effects of high temperature on rice grain, basmati rice was grown under two temperature conditions - 32 and 22 °C - during grain filling. High temperature decreased the grain filling period from 32 to 26 days, reducing yield by 6%, and caused a reduction in total starch (3.1%) and amylose content (22%). Measurable activities of key enzymes involved in sucrose to starch conversion, sucrose synthase, ADP-glucose pyrophosphorylase, starch phosphorylase and soluble starch synthase in endosperms developed at 32 °C were lower than those at 22 °C compared with similar ripening stage on an endosperm basis. In particular, granule-bound starch synthase (GBSS) activity was significantly lower than corresponding activity in endosperms developing at 22 °C during all developmental stages analyzed. Results suggest changes in amylose/amylopectin ratio observed in plants grown at 32 °C was attributable to a reduction in activity of GBSS, the sole enzyme responsible for amylose biosynthesis. © 2014 Society of Chemical Industry.

  10. 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.

  11. 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

  12. 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...

  13. Uniconazole-induced starch accumulation in the bioenergy crop duckweed (Landoltia punctata) I: transcriptome analysis of the effects of uniconazole on chlorophyll and endogenous hormone biosynthesis.

    Science.gov (United States)

    Liu, Yang; Fang, Yang; Huang, Mengjun; Jin, Yanling; Sun, Jiaolong; Tao, Xiang; Zhang, Guohua; He, Kaize; Zhao, Yun; Zhao, Hai

    2015-01-01

    Duckweed is a novel aquatic bioenergy crop that is found ubiquitously throughout the world. Uniconazole plays an important role in improving crop production through the regulation of endogenous hormone levels. We found that a high quantity and quality of duckweed growth can be achieved by uniconazole application, although the mechanisms are unknown. The fronds of Landoltia punctata were sprayed evenly with 800 mg/L uniconazole. The dry weight following treatment increased by 10% compared to the controls at 240 h. Endogenous cytokinin (CK) and abscisic acid (ABA) content both increased compared to the control, while the level of gibberellins (GAs) decreased. Additionally, gene expression profiling results showed that the expression of transcripts encoding key enzymes involved in endogenous CK and ABA biosynthesis were up-regulated, while the transcripts of key enzymes for GAs biosynthesis were down-regulated. On the other hand, chlorophyll a and chlorophyll b contents were both increased compared with the control. Moreover, the net photosynthetic rate was elevated to 25.6 μmol CO2/m(2)/s compared with the control value of 22.05 μmol CO2/m(2)/s. Importantly, the expression of some chlorophyll biosynthesis-related transcripts was up-regulated. Uniconazole treatment altered endogenous hormone levels and enhanced chlorophyll content and net photosynthetic rate in duckweed by regulating key enzymes involved in endogenous hormone and chlorophyll biosynthesis. The alterations of endogenous hormones and the increase of chlorophyll and photosynthetic rate data support the increase of biomass and starch accumulation.

  14. Trypanosoma cruzi response to sterol biosynthesis inhibitors: morphophysiological alterations leading to cell death.

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    Rafael Luis Kessler

    Full Text Available The protozoan parasite Trypanosoma cruzi displays similarities to fungi in terms of its sterol lipid biosynthesis, as ergosterol and other 24-alkylated sterols are its principal endogenous sterols. The sterol pathway is thus a potential drug target for the treatment of Chagas disease. We describe here a comparative study of the growth inhibition, ultrastructural and physiological changes leading to the death of T. cruzi cells following treatment with the sterol biosynthesis inhibitors (SBIs ketoconazole and lovastatin. We first calculated the drug concentration inhibiting epimastigote growth by 50% (EC(50/72 h or killing all cells within 24 hours (EC(100/24 h. Incubation with inhibitors at the EC(50/72 h resulted in interesting morphological changes: intense proliferation of the inner mitochondrial membrane, which was corroborated by flow cytometry and confocal microscopy of the parasites stained with rhodamine 123, and strong swelling of the reservosomes, which was confirmed by acridine orange staining. These changes to the mitochondria and reservosomes may reflect the involvement of these organelles in ergosterol biosynthesis or the progressive autophagic process culminating in cell lysis after 6 to 7 days of treatment with SBIs at the EC(50/72 h. By contrast, treatment with SBIs at the EC(100/24 h resulted in rapid cell death with a necrotic phenotype: time-dependent cytosolic calcium overload, mitochondrial depolarization and reservosome membrane permeabilization (RMP, culminating in cell lysis after a few hours of drug exposure. We provide the first demonstration that RMP constitutes the "point of no return" in the cell death cascade, and propose a model for the necrotic cell death of T. cruzi. Thus, SBIs trigger cell death by different mechanisms, depending on the dose used, in T. cruzi. These findings shed new light on ergosterol biosynthesis and the mechanisms of programmed cell death in this ancient protozoan parasite.

  15. Effects of lead on enzymes of porphyrine biosynthesis in chloroplasts and erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Hampp, R.; Kriebitzsch, C.; Ziegler, H.

    1974-01-01

    Two enzymes of the chlorophyll biosynthesis pathway, delta-aminolevulinic acid dehydratase (ALAD) and prophobilinogenase (PBGA), show a pronounced sensitivity to lead ion, as was shown in isolated chloroplasts of spinach. It has been reported by several authors that the activity of ALAD involved in the hemoglobine-biosynthesis in erythrocytes is also very sensitive to lead ions. Spinach chloroplasts were isolated and sonicated and the enzyme activity tested. Calf blood was collected with heparin and kept at 0/sup 0/C until enzyme determination. Hemolyzed erythrocytes (rapid freezing and thawing twice) were used as the source of enzymes. The incubation mixture was the same as for chloroplasts; the hemoglobin content per test was about 44 mg (ALAD) and 91 mg (PBGA). ALAD in erythrocytes is somewhat more sensitive to lead ions than ALAD in chloroplasts. PBGA in erythrocytes is also inhibited by Pb/sup 2 +/ ions, again more than the chloroplast enzyme. At all concentrations of Pb/sup 2 +/ checked in our experiments the percentage of inhibition was higher with PBGA. 3 references, 1 figure.

  16. 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

  17. Controlled extracellular biosynthesis of ZnS quantum dots by sulphate reduction bacteria in the presence of hydroxypropyl starch as a mediator

    Science.gov (United States)

    Qi, Shiyue; Zhang, Mi; Guo, Xingming; Yue, Lei; Wang, Jia; Shao, Ziqiang; Xin, Baoping

    2017-06-01

    Metal sulphide quantum dots (QDs) have broad applications. Sulphate-reducing bacteria (SRB) have been recognized as synthesizers of metal sulphides, with the characteristics of a high-production efficiency and easy product harvest. However, SRB are incapable of synthesizing metal sulphide QDs. In the present study, cheap hydroxypropyl starch (HPS) was used to assist SRB in manufacturing the ZnS QDs. The results exhibited that the HPS accelerated the growth of SRB and reduction of SO4 2+ into S2-, while it blocked the precipitation between S2- and Zn2+ to control the nucleation and growth of ZnS, resulting in the formation of ZnS QDs. When the HPS concentration increased from 0.2 to 1.6 g/L, the average crystal size (ACS) of ZnS QDs dropped from 5.95 to 3.34 nm, demonstrating the controlled biosynthesis of ZnS QDs. The ZnS QDs were coated or adhered to by both HPS and proteins, which played an important role in the controlled biosynthesis of ZnS QDs. The remarkable blue shift of the narrow UV absorption peak was due to the quantum confinement effect. The sequential variation in the colour of the photoluminescence spectrum (PL) from red to yellow suggested a tunable PL of the ZnS QDs. The current work demonstrated that SRB can fabricate the formation of ZnS QDs with a controlled size and tunable PL at a high-production rate of approximately 8.7 g/(L × week) through the simple mediation of HPS, with the yield being 7.46 times the highest yield in previously reported studies. The current work is of great importance to the commercialization of the biosynthesis of ZnS QDs.

  18. Autoclave and beta-amylolysis lead to reduced in vitro digestibility of starch.

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    Hickman, B Elliot; Janaswamy, Srinivas; Yao, Yuan

    2009-08-12

    In this study, a combination of autoclave and beta-amylolysis was used to modulate the digestibility of normal corn starch (NCS) and wheat starch (WS). The modification procedure comprised three cycles of autoclave at 35% moisture content and 121 degrees C, beta-amylolysis, and one additional cycle of autoclave. Starch materials were sampled at each stage and characterized. The fine structure of starch was determined using high-performance size-exclusion chromatography, the micromorphology of starch dispersion was imaged using cryo-SEM, the crystalline pattern was evaluated using wide-angle X-ray powder diffraction, and the digestibility was measured using Englyst assay. After beta-amylolysis, amylose was enriched (from 25.4 to 33.2% for NCS and from 27.5 to 32.8% for WS) and the branch density was increased (from 5.2 to 7.7% for NCS and from 5.3 to 7.9% for WS). Cryo-SEM images showed that the autoclave treatment led to the formation of a low-swelling, high-density gel network, whereas beta-amylolysis nearly demolished the network structure. The loss of A-type crystalline structure and the formation of B- and V-type structures resulted from autoclave, which suggests the formation of amylose-based ordered structure. Englyst assay indicated that, due to beta-amylolysis, the resistant starch (RS) content was increased to 30 from 11% of native NCS and to 23 from 9% of native WS. In contrast, autoclave showed only minor impact on RS levels. The increase of RS observed in this study is associated with enhanced branch density, which is different from the four types of RS commonly defined.

  19. The "Food Polymer Science" approach to the practice of industrial R&D, leading to patent estates based on fundamental starch science and technology.

    Science.gov (United States)

    Slade, Louise; Levine, Harry

    2018-04-13

    This article reviews the application of the "Food Polymer Science" approach to the practice of industrial R&D, leading to patent estates based on fundamental starch science and technology. The areas of patents and patented technologies reviewed here include: (a) soft-from-the-freezer ice creams and freezer-storage-stable frozen bread dough products, based on "cryostabilization technology" of frozen foods, utilizing commercial starch hydrolysis products (SHPs); (b) glassy-matrix encapsulation technology for flavors and other volatiles, based on structure-function relationships for commercial SHPs; (c) production of stabilized whole-grain wheat flours for biscuit products, based on the application of "solvent retention capacity" technology to develop flours with reduced damaged starch; (d) production of improved-quality, low-moisture cookies and crackers, based on pentosanase enzyme technology; (e) production of "baked-not-fried," chip-like, starch-based snack products, based on the use of commercial modified-starch ingredients with selected functionality; (f) accelerated staling of a starch-based food product from baked bread crumb, based on the kinetics of starch retrogradation, treated as a crystallization process for a partially crystalline glassy polymer system; and (g) a process for producing an enzyme-resistant starch, for use as a reduced-calorie flour replacer in a wide range of grain-based food products, including cookies, extruded expanded snacks, and breakfast cereals.

  20. Absence of functional peroxisomes does not lead to deficiency of enzymes involved in cholesterol biosynthesis

    NARCIS (Netherlands)

    Hogenboom, Sietske; Romeijn, Gerrit Jan; Houten, Sander M.; Baes, Myriam; Wanders, Ronald J. A.; Waterham, Hans R.

    2002-01-01

    To unravel the conflicting data concerning the dependence of human cholesterol biosynthesis on functional peroxisomes, we determined activities and levels of selected enzymes involved in cholesterol biosynthesis in livers of PEX5 knockout mice, a well-characterized model for human Zellweger

  1. Virus-Induced Silencing of Key Genes Leads to Differential Impact on Withanolide Biosynthesis in the Medicinal Plant, Withania somnifera.

    Science.gov (United States)

    Agarwal, Aditya Vikram; Singh, Deeksha; Dhar, Yogeshwar Vikram; Michael, Rahul; Gupta, Parul; Chandra, Deepak; Trivedi, Prabodh Kumar

    2018-02-01

    Withanolides are a collection of naturally occurring, pharmacologically active, secondary metabolites synthesized in the medicinally important plant, Withania somnifera. These bioactive molecules are C28-steroidal lactone triterpenoids and their synthesis is proposed to take place via the mevalonate (MVA) and 2-C-methyl-d-erythritol-4-phosphate (MEP) pathways through the sterol pathway using 24-methylene cholesterol as substrate flux. Although the phytochemical profiles as well as pharmaceutical activities of Withania extracts have been well studied, limited genomic information and difficult genetic transformation have been a major bottleneck towards understanding the participation of specific genes in withanolide biosynthesis. In this study, we used the Tobacco rattle virus (TRV)-mediated virus-induced gene silencing (VIGS) approach to study the participation of key genes from MVA, MEP and triterpenoid biosynthesis for their involvement in withanolide biosynthesis. TRV-infected W. somnifera plants displayed unique phenotypic characteristics and differential accumulation of total Chl as well as carotenoid content for each silenced gene suggesting a reduction in overall isoprenoid synthesis. Comprehensive expression analysis of putative genes of withanolide biosynthesis revealed transcriptional modulations conferring the presence of complex regulatory mechanisms leading to withanolide biosynthesis. In addition, silencing of genes exhibited modulated total and specific withanolide accumulation at different levels as compared with control plants. Comparative analysis also suggests a major role for the MVA pathway as compared with the MEP pathway in providing substrate flux for withanolide biosynthesis. These results demonstrate that transcriptional regulation of selected Withania genes of the triterpenoid biosynthetic pathway critically affects withanolide biosynthesis, providing new horizons to explore this process further, in planta.

  2. Biosynthesis of vitamin C by yeast leads to increased stress resistance.

    Directory of Open Access Journals (Sweden)

    Paola Branduardi

    Full Text Available BACKGROUND: In industrial large scale bio-reactions micro-organisms are generally exposed to a variety of environmental stresses, which might be detrimental for growth and productivity. Reactive oxygen species (ROS play a key role among the common stress factors--directly--through incomplete reduction of O(2 during respiration, or indirectly--caused by other stressing factors. Vitamin C or L-ascorbic acid acts as a scavenger of ROS, thereby potentially protecting cells from harmful oxidative products. While most eukaryotes synthesize ascorbic acid, yeast cells produce erythro-ascorbic acid instead. The actual importance of this antioxidant substance for the yeast is still a subject of scientific debate. METHODOLOGY/PRINCIPAL FINDINGS: We set out to enable Saccharomyces cerevisiae cells to produce ascorbic acid intracellularly to protect the cells from detrimental effects of environmental stresses. We report for the first time the biosynthesis of L-ascorbic acid from D-glucose by metabolically engineered yeast cells. The amount of L-ascorbic acid produced leads to an improved robustness of the recombinant cells when they are subjected to stress conditions as often met during industrial fermentations. Not only resistance against oxidative agents as H(2O(2 is increased, but also the tolerance to low pH and weak organic acids at low pH is increased. CONCLUSIONS/SIGNIFICANCE: This platform provides a new tool whose commercial applications may have a substantial impact on bio-industrial production of Vitamin C. Furthermore, we propose S. cerevisiae cells endogenously producing vitamin C as a cellular model to study the genesis/protection of ROS as well as genotoxicity.

  3. 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...

  4. Downregulation of chloroplast-targeted beta-amylase leads to a starch-excess phenotype in leaves

    DEFF Research Database (Denmark)

    Scheidig, A.; Fröhlich, A.; Schulze, S.

    2002-01-01

    showed that the protein product was a functional beta-amylase that could degrade both starch granules and solubilized amylopectin, while import experiments demonstrated that the beta-amylase was imported and processed into pea chloroplasts. To study the function of the protein in transitory starch......A functional screen in Escherichia coli was established to identify potato genes coding for proteins involved in transitory starch degradation. One clone isolated had a sequence very similar to a recently described chloroplast-targeted 5-amylase of Arabidopsis. Expression of the gene in E. coli...

  5. Structural Insight into the Core of CAD, the Multifunctional Protein Leading De Novo Pyrimidine Biosynthesis.

    Science.gov (United States)

    Moreno-Morcillo, María; Grande-García, Araceli; Ruiz-Ramos, Alba; Del Caño-Ochoa, Francisco; Boskovic, Jasminka; Ramón-Maiques, Santiago

    2017-06-06

    CAD, the multifunctional protein initiating and controlling de novo biosynthesis of pyrimidines in animals, self-assembles into ∼1.5 MDa hexamers. The structures of the dihydroorotase (DHO) and aspartate transcarbamoylase (ATC) domains of human CAD have been previously determined, but we lack information on how these domains associate and interact with the rest of CAD forming a multienzymatic unit. Here, we prove that a construct covering human DHO and ATC oligomerizes as a dimer of trimers and that this arrangement is conserved in CAD-like from fungi, which holds an inactive DHO-like domain. The crystal structures of the ATC trimer and DHO-like dimer from the fungus Chaetomium thermophilum confirm the similarity with the human CAD homologs. These results demonstrate that, despite being inactive, the fungal DHO-like domain has a conserved structural function. We propose a model that sets the DHO and ATC complex as the central element in the architecture of CAD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. In Vitro Biochemical Characterization of All Barley Endosperm Starch Synthases

    Directory of Open Access Journals (Sweden)

    Jose Antonio Cuesta-Seijo

    2016-01-01

    Full Text Available Starch is the main storage polysaccharide in cereals and the major source of calories in the human diet. It is synthesized by a panel of enzymes including five classes of starch synthases (SSs. While the overall starch synthase (SS reaction is known, the functional differences between the five SS classes are poorly understood. Much of our knowledge comes from analyzing mutant plants with altered SS activities, but the resulting data are often difficult to interpret as a result of pleitropic effects, competition between enzymes, overlaps in enzyme activity and disruption of multi-enzyme complexes. Here we provide a detailed biochemical study of the activity of all five classes of SSs in barley endosperm. Each enzyme was produced recombinantly in E. coli and the properties and modes of action in vitro were studied in isolation from other SSs and other substrate modifying activities. Our results define the mode of action of each SS class in unprecedented detail; we analyze their substrate selection, temperature dependence and stability, substrate affinity and temporal abundance during barley development. Our results are at variance with some generally accepted ideas about starch biosynthesis and might lead to the reinterpretation of results obtained in planta. In particular, they indicate that granule bound SS is capable of processive action even in the absence of a starch matrix, that SSI has no elongation limit, and that SSIV, believed to be critical for the initiation of starch granules, has maltoligosaccharides and not polysaccharides as its preferred substrates.

  7. Deficiencies in both starch synthase IIIa and branching enzyme IIb lead to a significant increase in amylose in SSIIa-inactive japonica rice seeds.

    Science.gov (United States)

    Asai, Hiroki; Abe, Natsuko; Matsushima, Ryo; Crofts, Naoko; Oitome, Naoko F; Nakamura, Yasunori; Fujita, Naoko

    2014-10-01

    Starch synthase (SS) IIIa has the second highest activity of the total soluble SS activity in developing rice endosperm. Branching enzyme (BE) IIb is the major BE isozyme, and is strongly expressed in developing rice endosperm. A mutant (ss3a/be2b) was generated from wild-type japonica rice which lacks SSIIa activity. The seed weight of ss3a/be2b was 74-94% of that of the wild type, whereas the be2b seed weight was 59-73% of that of the wild type. There were significantly fewer amylopectin short chains [degree of polymerization (DP) ≤13] in ss3a/be2b compared with the wild type. In contrast, the amount of long chains (DP ≥25) connecting clusters of amylopectin in ss3a/be2b was higher than in the wild type and lower than in be2b. The apparent amylose content of ss3a/be2b was 45%, which was >1.5 times greater than that of either ss3a or be2b. Both SSIIIa and BEIIb deficiencies led to higher activity of ADP-glucose pyrophosphorylase (AGPase) and granule-bound starch synthase I (GBSSI), which partly explains the high amylose content in the ss3a/be2b endosperm. The percentage apparent amylose content of ss3a and ss3a/be2b at 10 days after flowering (DAF) was higher than that of the wild type and be2b. At 20 DAF, amylopectin biosynthesis in be2b and ss3a/be2b was not observed, whereas amylose biosynthesis in these lines was accelerated at 30 DAF. These data suggest that the high amylose content in the ss3a/be2b mutant results from higher amylose biosynthesis at two stages, up to 20 DAF and from 30 DAF to maturity. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  8. 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...

  9. 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...

  10. A conserved ethylene biosynthesis enzyme leads to andromonoecy in two cucumis species.

    Directory of Open Access Journals (Sweden)

    Adnane Boualem

    Full Text Available Andromonoecy is a widespread sexual system in angiosperms, characterized by plants carrying both male and bisexual flowers. Monoecy is characterized by the presence of both male and female flowers on the same plant. In cucumber, these sexual forms are controlled by the identity of the alleles at the M locus. In melon, we recently showed that the transition from monoecy to andromonoecy result from a mutation in 1-aminocyclopropane-1-carboxylic acid synthase (ACS gene, CmACS-7. To isolate the andromonoecy gene in cucumber we used a candidate gene approach in combination with genetical and biochemical analysis. We demonstrated co-segregation of CsACS2, a close homolog of CmACS-7, with the M locus. Sequence analysis of CsACS2 in cucumber accessions identified four CsACS2 isoforms, three in andromonoecious and one in monoecious lines. To determine whether the andromonoecious phenotype is due to a loss of ACS enzymatic activity, we expressed the four isoforms in Escherichia coli and assayed their activity in vitro. Like in melon, the isoforms from the andromonoecious lines showed reduced to no enzymatic activity and the isoform from the monoecious line was active. Consistent with this, the mutations leading andromonoecy were clustered in the active site of the enzyme. Based on this, we concluded that active CsACS2 enzyme leads to the development of female flowers in monoecious lines, whereas a reduction of enzymatic activity yields hermaphrodite flowers. Consistent with this, CsACS2, like CmACS-7 in melon, is expressed specifically in carpel primordia of buds determined to develop carpels. Following ACS expression, inter-organ communication is likely responsible for the inhibition of stamina development. In both melon and cucumber, flower unisexuality seems to be the ancestral situation, as the majority of Cucumis species are monoecious. Thus, the ancestor gene of CmACS-7/CsACS2 likely have controlled the stamen development before speciation of

  11. Functional and structural characterization of plastidic starch phosphorylase during barley endosperm development

    DEFF Research Database (Denmark)

    Cuesta-Seijo, Jose A.; Ruzanski, Christian; Krucewicz, Katarzyna

    2017-01-01

    The production of starch is essential for human nutrition and represents a major metabolic flux in the biosphere. The biosynthesis of starch in storage organs like barley endosperm operates via two main pathways using different substrates: starch synthases use ADP-glucose to produce amylose......,4-glucans using HvPho1 from G1P as the sole substrate. The structural properties of HvPho1 provide insights into the low affinity of HvPho1 for large polysaccharides like starch or amylopectin. Our results suggest that HvPho1 may play a role during the initiation of starch biosynthesis in barley....... and amylopectin, the two major components of starch, whereas starch phosphorylase (Pho1) uses glucose-1-phosphate (G1P), a precursor for ADP-glucose production, to produce α-1,4 glucans. The significance of the Pho1 pathway in starch biosynthesis has remained unclear. To elucidate the importance of barley Pho1...

  12. Loss of ferulate 5-hydroxylase leads to Mediator-dependent inhibition of soluble phenylpropanoid biosynthesis in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Nickolas; Bonawitz, Nicholas D.; Nyffeler, Kayleigh E.; Chapple, Clint

    2015-06-05

    Phenylpropanoids are phenylalanine-derived specialized metabolites and include important structural components of plant cell walls, such as lignin and hydroxycinnamic acids, as well as ultraviolet and visible light-absorbing pigments, such as hydroxycinnamate esters (HCEs) and anthocyanins. Previous work has revealed a remarkable degree of plasticity in HCE biosynthesis, such that most Arabidopsis (Arabidopsis thaliana) mutants with blockages in the pathway simply redirect carbon flux to atypical HCEs. In contrast, the ferulic acid hydroxylase1 (fah1) mutant accumulates greatly reduced levels of HCEs, suggesting that phenylpropanoid biosynthesis may be repressed in response to the loss of FERULATE 5-HYDROXYLASE (F5H) activity. Here, we show that in fah1 mutant plants, the activity of HCE biosynthetic enzymes is not limiting for HCE accumulation, nor is phenylpropanoid flux diverted to the synthesis of cell wall components or flavonol glycosides. We further show that anthocyanin accumulation is also repressed in fah1 mutants and that this repression is specific to tissues in which F5H is normally expressed. Finally, we show that repression of both HCE and anthocyanin biosynthesis in fah1 mutants is dependent on the MED5a/5b subunits of the transcriptional coregulatory complex Mediator, which are similarly required for the repression of lignin biosynthesis and the stunted growth of the phenylpropanoid pathway mutant reduced epidermal fluorescence8. Taken together, these observations show that the synthesis of HCEs and anthocyanins is actively repressed in a MEDIATOR-dependent manner in Arabidopsis fah1 mutants and support an emerging model in which MED5a/5b act as central players in the homeostatic repression of phenylpropanoid metabolism.

  13. The rice dwarf virus P2 protein interacts with ent-kaurene oxidases in vivo, leading to reduced biosynthesis of gibberellins and rice dwarf symptoms.

    Science.gov (United States)

    Zhu, Shifeng; Gao, Feng; Cao, Xuesong; Chen, Mao; Ye, Gongyin; Wei, Chunhong; Li, Yi

    2005-12-01

    The mechanisms of viral diseases are a major focus of biology. Despite intensive investigations, how a plant virus interacts with host factors to cause diseases remains poorly understood. The Rice dwarf virus (RDV), a member of the genus Phytoreovirus, causes dwarfed growth phenotypes in infected rice (Oryza sativa) plants. The outer capsid protein P2 is essential during RDV infection of insects and thus influences transmission of RDV by the insect vector. However, its role during RDV infection within the rice host is unknown. By yeast two-hybrid and coimmunoprecipitation assays, we report that P2 of RDV interacts with ent-kaurene oxidases, which play a key role in the biosynthesis of plant growth hormones gibberellins, in infected plants. Furthermore, the expression of ent-kaurene oxidases was reduced in the infected plants. The level of endogenous GA1 (a major active gibberellin in rice vegetative tissues) in the RDV-infected plants was lower than that in healthy plants. Exogenous application of GA3 to RDV-infected rice plants restored the normal growth phenotypes. These results provide evidence that the P2 protein of RDV interferes with the function of a cellular factor, through direct physical interactions, that is important for the biosynthesis of a growth hormone leading to symptom expression. In addition, the interaction between P2 and rice ent-kaurene oxidase-like proteins may decrease phytoalexin biosynthesis and make plants more competent for virus replication. Moreover, P2 may provide a novel tool to investigate the regulation of GA metabolism for plant growth and development.

  14. The Rice Dwarf Virus P2 Protein Interacts with ent-Kaurene Oxidases in Vivo, Leading to Reduced Biosynthesis of Gibberellins and Rice Dwarf Symptoms1

    Science.gov (United States)

    Zhu, Shifeng; Gao, Feng; Cao, Xuesong; Chen, Mao; Ye, Gongyin; Wei, Chunhong; Li, Yi

    2005-01-01

    The mechanisms of viral diseases are a major focus of biology. Despite intensive investigations, how a plant virus interacts with host factors to cause diseases remains poorly understood. The Rice dwarf virus (RDV), a member of the genus Phytoreovirus, causes dwarfed growth phenotypes in infected rice (Oryza sativa) plants. The outer capsid protein P2 is essential during RDV infection of insects and thus influences transmission of RDV by the insect vector. However, its role during RDV infection within the rice host is unknown. By yeast two-hybrid and coimmunoprecipitation assays, we report that P2 of RDV interacts with ent-kaurene oxidases, which play a key role in the biosynthesis of plant growth hormones gibberellins, in infected plants. Furthermore, the expression of ent-kaurene oxidases was reduced in the infected plants. The level of endogenous GA1 (a major active gibberellin in rice vegetative tissues) in the RDV-infected plants was lower than that in healthy plants. Exogenous application of GA3 to RDV-infected rice plants restored the normal growth phenotypes. These results provide evidence that the P2 protein of RDV interferes with the function of a cellular factor, through direct physical interactions, that is important for the biosynthesis of a growth hormone leading to symptom expression. In addition, the interaction between P2 and rice ent-kaurene oxidase-like proteins may decrease phytoalexin biosynthesis and make plants more competent for virus replication. Moreover, P2 may provide a novel tool to investigate the regulation of GA metabolism for plant growth and development. PMID:16299167

  15. The effect of thai glutinous rice starch on the synthesis of lead zirconate (PbZrO3) nanofibers via the electrospinning method.

    Science.gov (United States)

    Nawanil, Chanisa; Vittayakorn, Wanwilai; Muanghua, Rangson; Niemcharoen, Surasak; Prachayawarakorn, Jutarat; Vittayakorn, Naratip

    2013-05-01

    This study synthesized blended lead zirconate (PbZrO3;PZ)/poly(ethylene oxide)(PEO)/Glutinous rice starch (GRS) nanofibers by the electrospinning method. A number of parameters such as the ratio between PEO and GRS and calcination temperature have been studied. The as-spun PZ/PEO/GRS composite and PZ fibers were characterized by TG-DTA, X-ray diffraction, FT-IR and SEM, respectively. SEM results showed that smooth and continuous fibers were obtained at the volume ratio of 10:2:1, PZ/PEO/GRS. After calcination of the as-spun PZ/PEO/GRS composite nanofibers at 650 degrees C for 4 h, PZ nanofibers with perovskite structure were obtained successfully. The fibers had a uniform and smooth surface without grain boundaries. However, when the calcination temperature increased to 750 degrees C and 850 degrees C, the fiber represented a necklace-like structure with grain boundaries arranged by grain to grain unit cell clusters.

  16. ENZYME RESISTANCE OF GENETICALLY MODIFIED STARCH POTATOES

    Directory of Open Access Journals (Sweden)

    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

  17. 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...

  18. 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

  19. Effect of Lead (Pb Exposure on the Activity of Superoxide Dismutase and Catalase in Battery Manufacturing Workers (BMW of Western Maharashtra (India with Reference to Heme biosynthesis

    Directory of Open Access Journals (Sweden)

    Kusal K. Das

    2006-12-01

    Full Text Available The aim of this study was to estimate the activity of superoxide dismutase (SOD and catalase in erythrocytes and malondialdehyde (MDA in plasma of battery manufacturing workers (BMW of Western Maharashtra (India who were occupationally exposed to lead (Pb over a long period of time (about 15 years. This study was also aimed to determine the Pb intoxication resulted in a disturbance of heme biosynthesis in BMW group. The blood Pb level of BMW group (n = 28 was found to be in the range of 25.8 – 78.0 μg/dL (mean + SD, 53.63 + 16.98 whereas in Pb unexposed control group (n = 35 the range was 2.8 – 22.0 μg/dL (mean + SD, 12.52 + 4.08. The blood level (Pb-B and urinary lead level (Pb-U were significantly increased in BMW group as compared to unexposed control. Though activated d- aminolevulinic acid dehydratase (ALAD activities in BMW group did not show any significant change when compared to control group but activated / non activated erythrocyte – ALAD activities in BMW group showed a significant increase. Erythrocyte- zinc protoporphyrin (ZPP, urinary daminolevulinic acid (ALA-U and porphobilinogen (PBG-U of BMW groups elevated significantly as compared to control. A positive correlation (r = 0.66, p 1.0 were observed in control group. Hematological study revealed a significant decrease of hemoglobin concentration, packed cell volume (% and other blood indices and a significant increase of total leucocytes count in BMW group in comparison to control group. The serum MDA content was significantly increased (p< 0.001 and the activities of antioxidant enzymes such as erythrocyte- SOD (p< 0.001 and erythrocytecatalase (p< 0.001 were significantly reduced in BMW group as compared to control group. A positive correlation (r = 0.45, p<0.02 between Pb-B and serum MDA level was observed in BMW group (Pb-B range 25.8 – 78.0 μg / dL but such significant correlation did not notice in

  20. 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

  1. PROTEIN TARGETING TO STARCH is required for localising GRANULE-BOUND STARCH SYNTHASE to starch granules and for normal amylose synthesis in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    David Seung

    2015-02-01

    Full Text Available The domestication of starch crops underpinned the development of human civilisation, yet we still do not fully understand how plants make starch. Starch is composed of glucose polymers that are branched (amylopectin or linear (amylose. The amount of amylose strongly influences the physico-chemical behaviour of starchy foods during cooking and of starch mixtures in non-food manufacturing processes. The GRANULE-BOUND STARCH SYNTHASE (GBSS is the glucosyltransferase specifically responsible for elongating amylose polymers and was the only protein known to be required for its biosynthesis. Here, we demonstrate that PROTEIN TARGETING TO STARCH (PTST is also specifically required for amylose synthesis in Arabidopsis. PTST is a plastidial protein possessing an N-terminal coiled coil domain and a C-terminal carbohydrate binding module (CBM. We discovered that Arabidopsis ptst mutants synthesise amylose-free starch and are phenotypically similar to mutants lacking GBSS. Analysis of granule-bound proteins showed a dramatic reduction of GBSS protein in ptst mutant starch granules. Pull-down assays with recombinant proteins in vitro, as well as immunoprecipitation assays in planta, revealed that GBSS physically interacts with PTST via a coiled coil. Furthermore, we show that the CBM domain of PTST, which mediates its interaction with starch granules, is also required for correct GBSS localisation. Fluorescently tagged Arabidopsis GBSS, expressed either in tobacco or Arabidopsis leaves, required the presence of Arabidopsis PTST to localise to starch granules. Mutation of the CBM of PTST caused GBSS to remain in the plastid stroma. PTST fulfils a previously unknown function in targeting GBSS to starch. This sheds new light on the importance of targeting biosynthetic enzymes to sub-cellular sites where their action is required. Importantly, PTST represents a promising new gene target for the biotechnological modification of starch composition, as it is

  2. 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).

  3. 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

  4. Microbial starch binding domains as a tool for targeting protein to ...

    African Journals Online (AJOL)

    jiq

    2013-10-09

    Oct 9, 2013 ... sweet potato starch granules during biosynthesis. Key words: Sweet ... Improvement of natural starch properties for industrial purposes can be ... 4°C. Subsequently, the root juice was collected and stored at -20°C for later use.

  5. High glucose suppresses human islet insulin biosynthesis by inducing miR-133a leading to decreased polypyrimidine tract binding protein-expression.

    Directory of Open Access Journals (Sweden)

    Rikard G Fred

    Full Text Available BACKGROUND: Prolonged periods of high glucose exposure results in human islet dysfunction in vitro. The underlying mechanisms behind this effect of high glucose are, however, unknown. The polypyrimidine tract binding protein (PTB is required for stabilization of insulin mRNA and the PTB mRNA 3'-UTR contains binding sites for the microRNA molecules miR-133a, miR-124a and miR-146. The aim of this study was therefore to investigate whether high glucose increased the levels of these three miRNAs in association with lower PTB levels and lower insulin biosynthesis rates. METHODOLOGY/PRINCIPAL FINDINGS: Human islets were cultured for 24 hours in the presence of low (5.6 mM or high glucose (20 mM. Islets were also exposed to sodium palmitate or the proinflammatory cytokines IL-1beta and IFN-gamma, since saturated free fatty acids and cytokines also cause islet dysfunction. RNA was then isolated for real-time RT-PCR analysis of miR-133a, miR-124a, miR-146, insulin mRNA and PTB mRNA contents. Insulin biosynthesis rates were determined by radioactive labeling and immunoprecipitation. Synthetic miR-133a precursor and inhibitor were delivered to dispersed islet cells by lipofection, and PTB was analyzed by immunoblotting following culture at low or high glucose. Culture in high glucose resulted in increased islet contents of miR-133a and reduced contents of miR-146. Cytokines increased the contents of miR-146. The insulin and PTB mRNA contents were unaffected by high glucose. However, both PTB protein levels and insulin biosynthesis rates were decreased in response to high glucose. The miR-133a inhibitor prevented the high glucose-induced decrease in PTB and insulin biosynthesis, and the miR-133a precursor decreased PTB levels and insulin biosynthesis similarly to high glucose. CONCLUSION: Prolonged high-glucose exposure down-regulates PTB levels and insulin biosynthesis rates in human islets by increasing miR-133a levels. We propose that this mechanism

  6. 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

  7. 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

  8. Propiconazole-enhanced hepatic cell proliferation is associated with dysregulation of the cholesterol biosynthesis pathway leading to activation of Erk1/2 through Ras farnesylation

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Lynea A.; Moore, Tanya; Nesnow, Stephen, E-mail: nesnow.stephen@epa.gov

    2012-04-15

    Propiconazole is a mouse hepatotumorigenic fungicide designed to inhibit CYP51, a key enzyme in the biosynthesis of ergosterol in fungi and is widely used in agriculture to prevent fungal growth. Metabolomic studies in mice revealed that propiconazole increased levels of hepatic cholesterol metabolites and bile acids, and transcriptomic studies revealed that genes within the cholesterol biosynthesis, cholesterol metabolism and bile acid biosyntheses pathways were up-regulated. Hepatic cell proliferation was also increased by propiconazole. AML12 immortalized hepatocytes were used to study propiconazole's effects on cell proliferation focusing on the dysregulation of cholesterol biosynthesis and resulting effects on Ras farnesylation and Erk1/2 activation as a primary pathway. Mevalonate, a key intermediate in the cholesterol biosynthesis pathway, increases cell proliferation in several cancer cell lines and tumors in vivo and serves as the precursor for isoprenoids (e.g. farnesyl pyrophosphate) which are crucial in the farnesylation of the Ras protein by farnesyl transferase. Farnesylation targets Ras to the cell membrane where it is involved in signal transduction, including the mitogen-activated protein kinase (MAPK) pathway. In our studies, mevalonic acid lactone (MVAL), a source of mevalonic acid, increased cell proliferation in AML12 cells which was reduced by farnesyl transferase inhibitors (L-744,832 or manumycin) or simvastatin, an HMG-CoA reductase inhibitor, indicating that this cell system responded to alterations in the cholesterol biosynthesis pathway. Cell proliferation in AML12 cells was increased by propiconazole which was reversed by co-incubation with L-744,832 or simvastatin. Increasing concentrations of exogenous cholesterol muted the proliferative effects of propiconazole and the inhibitory effects of L-733,832, results ascribed to reduced stimulation of the endogenous cholesterol biosynthesis pathway. Western blot analysis of subcellular

  9. 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.

  10. 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)

  11. In vitro biochemical characterization of all barley endosperm starch synthases

    DEFF Research Database (Denmark)

    Cuesta-Seijo, Jose A.; Nielsen, Morten M.; Ruzanski, Christian

    2016-01-01

    Starch is the main storage polysaccharide in cereals and the major source of calories in the human diet. It is synthesized by a panel of enzymes including five classes of starch synthases (SSs). While the overall starch synthase (SS) reaction is known, the functional differences between the five SS....... Here we provide a detailed biochemical study of the activity of all five classes of SSs in barley endosperm. Each enzyme was produced recombinantly in E. coli and the properties and modes of action in vitro were studied in isolation from other SSs and other substrate modifying activities. Our results...... define the mode of action of each SS class in unprecedented detail; we analyze their substrate selection, temperature dependence and stability, substrate affinity and temporal abundance during barley development. Our results are at variance with some generally accepted ideas about starch biosynthesis...

  12. 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

  13. High glucose suppresses human islet insulin biosynthesis by inducing miR-133a leading to decreased polypyrimidine tract binding protein-expression

    DEFF Research Database (Denmark)

    Fred, Rikard G; Bang-Berthelsen, Claus H; Mandrup-Poulsen, Thomas

    2010-01-01

    BACKGROUND: Prolonged periods of high glucose exposure results in human islet dysfunction in vitro. The underlying mechanisms behind this effect of high glucose are, however, unknown. The polypyrimidine tract binding protein (PTB) is required for stabilization of insulin mRNA and the PTB mRNA 3......'-UTR contains binding sites for the microRNA molecules miR-133a, miR-124a and miR-146. The aim of this study was therefore to investigate whether high glucose increased the levels of these three miRNAs in association with lower PTB levels and lower insulin biosynthesis rates. METHODOLOGY...... for real-time RT-PCR analysis of miR-133a, miR-124a, miR-146, insulin mRNA and PTB mRNA contents. Insulin biosynthesis rates were determined by radioactive labeling and immunoprecipitation. Synthetic miR-133a precursor and inhibitor were delivered to dispersed islet cells by lipofection, and PTB...

  14. Serine biosynthesis and transport defects.

    Science.gov (United States)

    El-Hattab, Ayman W

    2016-07-01

    l-serine is a non-essential amino acid that is biosynthesized via the enzymes phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). Besides its role in protein synthesis, l-serine is a potent neurotrophic factor and a precursor of a number of essential compounds including phosphatidylserine, sphingomyelin, glycine, and d-serine. Serine biosynthesis defects result from impairments of PGDH, PSAT, or PSP leading to systemic serine deficiency. Serine biosynthesis defects present in a broad phenotypic spectrum that includes, at the severe end, Neu-Laxova syndrome, a lethal multiple congenital anomaly disease, intermediately, infantile serine biosynthesis defects with severe neurological manifestations and growth deficiency, and at the mild end, the childhood disease with intellectual disability. A serine transport defect resulting from deficiency of the ASCT1, the main transporter for serine in the central nervous system, has been recently described in children with neurological manifestations that overlap with those observed in serine biosynthesis defects. l-serine therapy may be beneficial in preventing or ameliorating symptoms in serine biosynthesis and transport defects, if started before neurological damage occurs. Herein, we review serine metabolism and transport, the clinical, biochemical, and molecular aspects of serine biosynthesis and transport defects, the mechanisms of these diseases, and the potential role of serine therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. 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

  16. 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...

  17. Creation of a high-amylose durum wheat through mutagenesis of starch synthase II (SSIIa)

    Science.gov (United States)

    In cereal seeds mutations in one or more starch synthases lead to decreased amylopectin and increased amylose content. Here, the impact of starch synthase IIa (SSIIa or SGP-1) mutations upon durum starch was investigated. A screen of durum accessions identified two lines lacking SGP-A1, the A geno...

  18. 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.

  19. Regulation of cell wall biosynthesis.

    Science.gov (United States)

    Zhong, Ruiqin; Ye, Zheng-Hua

    2007-12-01

    Plant cell walls differ in their amount and composition among various cell types and even in different microdomains of the wall of a given cell. Plants must have evolved regulatory mechanisms controlling biosynthesis, targeted secretion, and assembly of wall components to achieve the heterogeneity in cell walls. A number of factors, including hormones, the cytoskeleton, glycosylphosphatidylinositol-anchored proteins, phosphoinositides, and sugar nucleotide supply, have been implicated in the regulation of cell wall biosynthesis or deposition. In the past two years, there have been important discoveries in transcriptional regulation of secondary wall biosynthesis. Several transcription factors in the NAC and MYB families have been shown to be the key switches for activation of secondary wall biosynthesis. These studies suggest a transcriptional network comprised of a hierarchy of transcription factors is involved in regulating secondary wall biosynthesis. Further investigation and integration of the regulatory players participating in the making of cell walls will certainly lead to our understanding of how wall amounts and composition are controlled in a given cell type. This may eventually allow custom design of plant cell walls on the basis of our needs.

  20. 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.

  1. 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...

  2. 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

  3. 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...

  4. Phosphate fertilization changes the characteristics of 'Maçã' banana starch.

    Science.gov (United States)

    Mesquita, Camila de Barros; Garcia, Émerson Loli; Bolfarini, Ana Carolina Batista; Leonel, Sarita; Franco, Célia Maria L; Leonel, Magali

    2018-06-01

    The unripe banana has been studied as a potential source of starch for use in various applications. Considering the importance of phosphorus in the biosynthesis of the starch and also the interference of this mineral in starch properties, in this study it was evaluated the effect of rates of phosphate fertilizer applied in the cultivation of 'Maçã' banana on the characteristics of the starch. Starches extracted from fruits from different treatments were analyzed for morphological characteristics, X-ray diffraction pattern, relative crystallinity, granule size, amylose, resistant starch and phosphorus levels, as well as, for pasting and thermal properties. Results showed that the phosphate fertilization has interference on the characteristics of the banana starch led to increase of phosphorus content and size of the granules, reduction of crystallinity and resistant starch content, decrease of viscosity peak, breakdown, final viscosity, setback, transitions temperatures and enthalpy. These changes caused by phosphate fertilizer conditions can be increase the applications of the 'Maçã' banana starch. Copyright © 2018. Published by Elsevier B.V.

  5. 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.

  6. Repression of a novel isoform of disproportionating enzyme (stDPE2) in potato leads to inhibition of starch degradation in leaves but not tubers stored at low temperature

    DEFF Research Database (Denmark)

    Lloyd, J.R.; Blennow, A.; Burhenne, K.

    2004-01-01

    and tubers. Transgenic potato plants were made in which its presence was almost completely eliminated. It could be demonstrated that starch degradation was repressed in leaves of the transgenic plants but that cold-induced sweetening was not affected in tubers stored at 4degreesC. No evidence could be found...

  7. Improved Starch Digestion of Sucrase-deficient Shrews Treated With Oral Glucoamylase Enzyme Supplements.

    Science.gov (United States)

    Nichols, Buford L; Avery, Stephen E; Quezada-Calvillo, Roberto; Kilani, Shadi B; Lin, Amy Hui-Mei; Burrin, Douglas G; Hodges, Benjamin E; Chacko, Shaji K; Opekun, Antone R; Hindawy, Marwa El; Hamaker, Bruce R; Oda, Sen-Ichi

    2017-08-01

    Although named because of its sucrose hydrolytic activity, this mucosal enzyme plays a leading role in starch digestion because of its maltase and glucoamylase activities. Sucrase-deficient mutant shrews, Suncus murinus, were used as a model to investigate starch digestion in patients with congenital sucrase-isomaltase deficiency.Starch digestion is much more complex than sucrose digestion. Six enzyme activities, 2 α-amylases (Amy), and 4 mucosal α-glucosidases (maltases), including maltase-glucoamylase (Mgam) and sucrase-isomaltase (Si) subunit activities, are needed to digest starch to absorbable free glucose. Amy breaks down insoluble starch to soluble dextrins; mucosal Mgam and Si can either directly digest starch to glucose or convert the post-α-amylolytic dextrins to glucose. Starch digestion is reduced because of sucrase deficiency and oral glucoamylase enzyme supplement can correct the starch maldigestion. The aim of the present study was to measure glucogenesis in suc/suc shrews after feeding of starch and improvement of glucogenesis by oral glucoamylase supplements. Sucrase mutant (suc/suc) and heterozygous (+/suc) shrews were fed with C-enriched starch diets. Glucogenesis derived from starch was measured as blood C-glucose enrichment and oral recombinant C-terminal Mgam glucoamylase (M20) was supplemented to improve starch digestion. After feedings, suc/suc and +/suc shrews had different starch digestions as shown by blood glucose enrichment and the suc/suc had lower total glucose concentrations. Oral supplements of glucoamylase increased suc/suc total blood glucose and quantitative starch digestion to glucose. Sucrase deficiency, in this model of congenital sucrase-isomaltase deficiency, reduces blood glucose response to starch feeding. Supplementing the diet with oral recombinant glucoamylase significantly improved starch digestion in the sucrase-deficient shrew.

  8. 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)

  9. Novel bioassay for the discovery of inhibitors of the 2-C-methyl-D-erythritol 4-phosphate (MEP and terpenoid pathways leading to carotenoid biosynthesis.

    Directory of Open Access Journals (Sweden)

    Natália Corniani

    Full Text Available The 2-C-methyl-D-erythritol 4-phosphate (MEP pathway leads to the synthesis of isopentenyl diphosphate in plastids. It is a major branch point providing precursors for the synthesis of carotenoids, tocopherols, plastoquinone and the phytyl chain of chlorophylls, as well as the hormones abscisic acid and gibberellins. Consequently, disruption of this pathway is harmful to plants. We developed an in vivo bioassay that can measure the carbon flow through the carotenoid pathway. Leaf cuttings are incubated in the presence of a phytoene desaturase inhibitor to induce phytoene accumulation. Any compound reducing the level of phytoene accumulation is likely to interfere with either one of the steps in the MEP pathway or the synthesis of geranylgeranyl diphosphate. This concept was tested with known inhibitors of steps of the MEP pathway. The specificity of this in vivo bioassay was also verified by testing representative herbicides known to target processes outside of the MEP and carotenoid pathways. This assay enables the rapid screen of new inhibitors of enzymes preceding the synthesis of phytoene, though there are some limitations related to the non-specific effect of some inhibitors on this assay.

  10. Prececal digestibility of various sources of starch in minipigs with or without experimentally induced exocrine pancreatic insufficiency.

    Science.gov (United States)

    Mösseler, A; Kramer, N; Becker, C; Gregory, P C; Kamphues, J

    2012-12-01

    Low prececal digestibility of starch leads to a higher starch flux into the hindgut, causing a forced microbial fermentation, energy losses, and meteorism. For exocrine pancreatic insufficiency (EPI), lack of pancreatic amylase can be compensated mostly by hindgut fermentation of starch. Even in pigs with complete loss of pancreatic secretion, starch digestibility over the entire tract is reaching levels of controls. To optimize diets for human patients with EPI, the proportion of starch that is digested by the ileum is important. Minipigs were fitted with an ileocecal reentrant fistula (n = 8) to determine prececal digestibility of starch. In 5 minipigs the pancreatic duct was ligated (PL) to induce EPI; 3 minipigs served as controls (Con). Various starch sources were tested in a 1-d screening test; therefore, disappearance rate (DR) instead of digestibility was used. Test meals consisted of 169 g DM of a basal diet plus 67.5 g DM of the starch (without thermal treatment; purified; starch content of 89 to 94.5%) and Cr(2)O(3). The test meal contained (% of DM) starch, 67; crude fat, 1.69; CP, 15; crude fiber, 2.0; and Cr(2)O(3), 0.25. In PL, prececal DR of starch was lower than in Con (P 90%) but was lower (P < 0.05) for potato (Solanum tuberosum) starch (75.4%). In PL, prececal DR of starch was higher (P < 0.05) for wheat (Triticum aestivum) starch (61.2%) than corn (Zea mays) starch (43.0%) and rice (Oryza sativa) starch (29.2%) and intermediate for potato and field pea (Pisum sativum) starch. For patients with EPI, wheat starch seems favorable due to the higher prececal digestibility whereas raw corn and rice starch should be avoided.

  11. Proteomic Analysis Reveals Coordinated Regulation of Anthocyanin Biosynthesis through Signal Transduction and Sugar Metabolism in Black Rice Leaf.

    Science.gov (United States)

    Chen, Linghua; Huang, Yining; Xu, Ming; Cheng, Zuxin; Zheng, Jingui

    2017-12-15

    Black rice ( Oryza sativa L.) is considered to be a healthy food due to its high content of anthocyanins in the pericarp. The synthetic pathway of anthocyanins in black rice grains has been identified, however, the proteomic profile of leaves during grain development is still unclear. Here, isobaric Tags Relative and Absolute Quantification (iTRAQ) MS/MS was carried out to identify statistically significant changes of leaf proteome in the black rice during grain development. Throughout three sequential developmental stages, a total of 3562 proteins were detected and 24 functional proteins were differentially expressed 3-10 days after flowering (DAF). The detected proteins are known to be involved in various biological processes and most of these proteins were related to gene expression regulatory (33.3%), signal transduction (16.7%) and developmental regulation and hormone-like proteins (12.5%). The coordinated changes were consistent with changes in regulatory proteins playing a leading role in leaves during black rice grain development. This indicated that signal transduction between leaves and grains may have an important role in anthocyanin biosynthesis and accumulation during grain development of black rice. In addition, four identified up-regulated proteins associated with starch metabolism suggested that the remobilization of nutrients for starch synthesis plays a potential role in anthocyanin biosynthesis of grain. The mRNA transcription for eight selected proteins was validated with quantitative real-time PCR. Our results explored the proteomics of the coordination between leaf and grain in anthocyanins biosynthesis of grain, which might be regulated by signal transduction and sugar metabolism in black rice leaf.

  12. Proteomic Analysis Reveals Coordinated Regulation of Anthocyanin Biosynthesis through Signal Transduction and Sugar Metabolism in Black Rice Leaf

    Directory of Open Access Journals (Sweden)

    Linghua Chen

    2017-12-01

    Full Text Available Black rice (Oryza sativa L. is considered to be a healthy food due to its high content of anthocyanins in the pericarp. The synthetic pathway of anthocyanins in black rice grains has been identified, however, the proteomic profile of leaves during grain development is still unclear. Here, isobaric Tags Relative and Absolute Quantification (iTRAQ MS/MS was carried out to identify statistically significant changes of leaf proteome in the black rice during grain development. Throughout three sequential developmental stages, a total of 3562 proteins were detected and 24 functional proteins were differentially expressed 3–10 days after flowering (DAF. The detected proteins are known to be involved in various biological processes and most of these proteins were related to gene expression regulatory (33.3%, signal transduction (16.7% and developmental regulation and hormone-like proteins (12.5%. The coordinated changes were consistent with changes in regulatory proteins playing a leading role in leaves during black rice grain development. This indicated that signal transduction between leaves and grains may have an important role in anthocyanin biosynthesis and accumulation during grain development of black rice. In addition, four identified up-regulated proteins associated with starch metabolism suggested that the remobilization of nutrients for starch synthesis plays a potential role in anthocyanin biosynthesis of grain. The mRNA transcription for eight selected proteins was validated with quantitative real-time PCR. Our results explored the proteomics of the coordination between leaf and grain in anthocyanins biosynthesis of grain, which might be regulated by signal transduction and sugar metabolism in black rice leaf.

  13. 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

  14. Hydroxyethyl starch for resuscitation

    DEFF Research Database (Denmark)

    Haase, Nicolai; Perner, Anders

    2013-01-01

    PURPOSE OF REVIEW: Resuscitation with hydroxyethyl starch (HES) is controversial. In this review, we will present the current evidence for the use of HES solutions including data from recent high-quality randomized clinical trials. RECENT FINDINGS: Meta-analyses of HES vs. control fluids show clear...

  15. Resistant starch in cassava products

    Directory of Open Access Journals (Sweden)

    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.

  16. 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

  17. 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

  18. Hydroxyethyl starch in sepsis

    DEFF Research Database (Denmark)

    Haase, Nicolai Rosenkrantz Segelcke

    2014-01-01

    BACKGROUND: Hydroxyethyl starch (HES) is a colloid that has been widely used for fluid resuscitation for decades. The newest generation of HES, tetrastarch, was believed to provide an efficient volume expansion without causing the side effects observed with former HES solutions. However, this bel......BACKGROUND: Hydroxyethyl starch (HES) is a colloid that has been widely used for fluid resuscitation for decades. The newest generation of HES, tetrastarch, was believed to provide an efficient volume expansion without causing the side effects observed with former HES solutions. However...... types of patients is unclear, but so far no group of patients with an overall benefit of HES beyond surrogate markers has been identified. In line with this, the European Medicines Agency's Pharmacovigilance Risk Assessment Committee now recommends that the marketing authorisations of all HES solutions...

  19. 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.

  20. 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)

  1. Poly(Lactic Acid) Filled with Cassava Starch-g-Soybean Oil Maleate

    OpenAIRE

    Kiangkitiwan, Nopparut; Srikulkit, Kawee

    2013-01-01

    Poly(lactic acid), PLA, is a biodegradable polymer, but its applications are limited by its high cost and relatively poorer properties when compared to petroleum-based plastics. The addition of starch powder into PLA is one of the most promising efforts because starch is an abundant and cheap biopolymer. However, the challenge is the major problem associated with poor interfacial adhesion between the hydrophilic starch granules and the hydrophobic PLA, leading to poorer mechanical properties....

  2. Structural modification in the formation of starch – silver nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Begum, S. N. Suraiya; Ramasamy, Radha Perumal, E-mail: perumal.ramasamy@gmail.com [Department of Applied Science and Technology, A.C.Tech. Campus, Anna University, Chennai – 600 025 (India); Aswal, V. K. [Solid State Physics Division, Bhabha Atomic Research Center, Trombay, Mumbai (India)

    2016-05-23

    Polymer based nanocomposites have gained wide applications in field of battery technology. Starch is a naturally occurring polysaccharide with sustainable properties such as biodegradable, non toxic, excellent film forming capacity and it also act as reducing agent for the metal nanoparticles. In our research various concentration of silver nitrate (AgNO{sub 3}) was added to the starch solution and films were obtained using solution casting method. Surface electron microscope (SEM) of the films shows modifications depending upon the concentration of AgNO{sub 3}. Small angle neutron scattering (SANS) analysis showed that addition of silver nitrate modifies the starch to disc like structures and with increasing the AgNO{sub 3} concentration leads to the formation of fractals. This research could benefit battery technology where solid polymer membranes using starch is used.

  3. Structural modification in the formation of starch – silver nanocomposites

    International Nuclear Information System (INIS)

    Begum, S. N. Suraiya; Ramasamy, Radha Perumal; Aswal, V. K.

    2016-01-01

    Polymer based nanocomposites have gained wide applications in field of battery technology. Starch is a naturally occurring polysaccharide with sustainable properties such as biodegradable, non toxic, excellent film forming capacity and it also act as reducing agent for the metal nanoparticles. In our research various concentration of silver nitrate (AgNO_3) was added to the starch solution and films were obtained using solution casting method. Surface electron microscope (SEM) of the films shows modifications depending upon the concentration of AgNO_3. Small angle neutron scattering (SANS) analysis showed that addition of silver nitrate modifies the starch to disc like structures and with increasing the AgNO_3 concentration leads to the formation of fractals. This research could benefit battery technology where solid polymer membranes using starch is used.

  4. Structural modification in the formation of starch - silver nanocomposites

    Science.gov (United States)

    Begum, S. N. Suraiya; Aswal, V. K.; Ramasamy, Radha Perumal

    2016-05-01

    Polymer based nanocomposites have gained wide applications in field of battery technology. Starch is a naturally occurring polysaccharide with sustainable properties such as biodegradable, non toxic, excellent film forming capacity and it also act as reducing agent for the metal nanoparticles. In our research various concentration of silver nitrate (AgNO3) was added to the starch solution and films were obtained using solution casting method. Surface electron microscope (SEM) of the films shows modifications depending upon the concentration of AgNO3. Small angle neutron scattering (SANS) analysis showed that addition of silver nitrate modifies the starch to disc like structures and with increasing the AgNO3 concentration leads to the formation of fractals. This research could benefit battery technology where solid polymer membranes using starch is used.

  5. 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.

  6. 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.

  7. Influence of nanoparticles on the properties of bionanocomposites from cassava starch

    International Nuclear Information System (INIS)

    Paglicawan, Marissa A.; Emolaga, Carlo S.; Navarro, Ma. Teresa V.; Celorico, Josefina; Basilia, Blessie A.

    2015-01-01

    Plastics are widely used packaging materials for food and non-food products due to their desirable material properties and low cost. However, the merits of plastic products have been overshadowed by its non-degradable nature, thereby leading to waste disposal problems. Because of the environmental problem, many researchers are facing to minimize non-degradable to biodegradable materials. Starch is one of the most promising natural polymers because of its inherent biodegradability, overwhelming abundance and its renewability. One of the abundant starch is cassava. The Manihot exculenta Crantz, is known as camoteng-kahoy or balinghoy in the Philippines. The production of thermoplastic starch (also known as plasticized starch or TPS) basically involves three essential components, namely: starch, plasticizer and thermomechanical energy. However, this material has high water solubility and may lose their mechanical properties in humid conditions. One of the possible ways to overcome this problem is through nanocomposite in which consist of a polymer matrix reinforced with nano-dimensional particles. This research involves the processing of cassava starch into thermoplastic starch for packaging application that can be biodegraded in soil or compostable after its usage. Thermoplastic starchs from cassava starch and different nanomaterials were processed by melt-blending method in a twin-screw extruder. The four nanofillers - nanoclay (NC), halloysite nanotube (HNT), nanozeolite (NZ), and nanocalcium carbonate (NCC) were incorporated into the starch matrix in a 3 phr concentration. The resulting biocomposites were characterized in terms of mechanical properties, morphology, thermal properties, moisture absorption, and crystallinity. The newly developed technology based on cassava starch/nano-scale particles nanocomposites upgrade the hdydrophylic and mechanical properties of starch based films. Homogeneously dispersing nanometer size materials, with high length

  8. New perspectives on the role of α- and β-amylases in transient starch synthesis.

    Science.gov (United States)

    Wu, Alex Chi; Ral, Jean-Philippe; Morell, Matthew K; Gilbert, Robert G

    2014-01-01

    Transient starch in leaves is synthesized by various biosynthetic enzymes in the chloroplasts during the light period. This paper presents the first mathematical model for the (bio)synthesis of the chain-length distribution (CLD) of transient starch to aid the understanding of this synthesis. The model expresses the rate of change of the CLD in terms of the actions of the enzymes involved. Using this to simulate the experimental CLD with different enzyme combinations is a new means to test for enzymes that are significant to the rate of change of the CLD during synthesis. Comparison between the simulated CLD from different enzyme combinations and the experimental CLD in the leaves of the model plant Arabidopsis thaliana indicate α-amylase, in addition to the core starch biosynthetic enzymes, is also involved in the modification of glucans for the synthesis of insoluble starch granules. The simulations suggest involvement of β-amylase, in the absence of α-amylase in mutants, slows the rate of attaining a crystalline-competent CLD for crystallization of glucans to form insoluble starch. This suggests a minor role of β-amylase in shaping normal starch synthesis. The model simulation predicts that debranching of glucans is an efficient mechanism for the attainment of crystalline-competent CLD; however, attaining this is still possible, albeit slower, through combinations of α- and β-amylase in the absence of isoamylase-type debranching enzyme. In Arabidopsis defective in one of the isoamylase-type debranching enzymes, the impact of α-amylase in starch synthesis is reduced, while β-amylase becomes significantly involved, slowing the rate of synthesis in this mutant. Modeling of transient starch CLD brings to light previously unrecognized but significant effects of α- and β-amylase on the rate of transient starch synthesis.

  9. New perspectives on the role of α- and β-amylases in transient starch synthesis.

    Directory of Open Access Journals (Sweden)

    Alex Chi Wu

    Full Text Available Transient starch in leaves is synthesized by various biosynthetic enzymes in the chloroplasts during the light period. This paper presents the first mathematical model for the (biosynthesis of the chain-length distribution (CLD of transient starch to aid the understanding of this synthesis. The model expresses the rate of change of the CLD in terms of the actions of the enzymes involved. Using this to simulate the experimental CLD with different enzyme combinations is a new means to test for enzymes that are significant to the rate of change of the CLD during synthesis. Comparison between the simulated CLD from different enzyme combinations and the experimental CLD in the leaves of the model plant Arabidopsis thaliana indicate α-amylase, in addition to the core starch biosynthetic enzymes, is also involved in the modification of glucans for the synthesis of insoluble starch granules. The simulations suggest involvement of β-amylase, in the absence of α-amylase in mutants, slows the rate of attaining a crystalline-competent CLD for crystallization of glucans to form insoluble starch. This suggests a minor role of β-amylase in shaping normal starch synthesis. The model simulation predicts that debranching of glucans is an efficient mechanism for the attainment of crystalline-competent CLD; however, attaining this is still possible, albeit slower, through combinations of α- and β-amylase in the absence of isoamylase-type debranching enzyme. In Arabidopsis defective in one of the isoamylase-type debranching enzymes, the impact of α-amylase in starch synthesis is reduced, while β-amylase becomes significantly involved, slowing the rate of synthesis in this mutant. Modeling of transient starch CLD brings to light previously unrecognized but significant effects of α- and β-amylase on the rate of transient starch synthesis.

  10. Improved starch digestion of sucrase deficient shrews treated with oral glucoamylase enzyme supplements

    Science.gov (United States)

    Although named because of its sucrose hydrolytic activity, this mucosal enzyme plays a leading role in starch digestion because of its maltase and glucoamylase activities. Sucrase deficient mutant shrews, Suncus murinus, were used as a model to investigate starch digestion in patients with Congenita...

  11. Assimilation of wheat starch in patients with chronic pancreatitis. Positive effect of enzyme replacement

    DEFF Research Database (Denmark)

    Nordgaard, I; Rumessen, J J; Gudmand-Høyer, E

    1992-01-01

    Pancreatic insufficiency due to chronic pancreatitis may lead to symptomatic malabsorption of both starch and fat. The absorption capacity of wheat starch has not been studied previously in patients with chronic pancreatitis, although this carbohydrate is a quantitatively important component of t...

  12. Starches, Sugars and Obesity

    Directory of Open Access Journals (Sweden)

    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.

  13. Nucleoside antibiotics: biosynthesis, regulation, and biotechnology.

    Science.gov (United States)

    Niu, Guoqing; Tan, Huarong

    2015-02-01

    The alarming rise in antibiotic-resistant pathogens has coincided with a decline in the supply of new antibiotics. It is therefore of great importance to find and create new antibiotics. Nucleoside antibiotics are a large family of natural products with diverse biological functions. Their biosynthesis is a complex process through multistep enzymatic reactions and is subject to hierarchical regulation. Genetic and biochemical studies of the biosynthetic machinery have provided the basis for pathway engineering and combinatorial biosynthesis to create new or hybrid nucleoside antibiotics. Dissection of regulatory mechanisms is leading to strategies to increase the titer of bioactive nucleoside antibiotics. Copyright © 2014. Published by Elsevier Ltd.

  14. 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

  15. Identification and phylogenetic analysis of a novel starch synthase in maize

    Directory of Open Access Journals (Sweden)

    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.

  16. The adsorption of α-amylase on barley proteins affects the in vitro digestion of starch in barley flour.

    Science.gov (United States)

    Yu, Wenwen; Zou, Wei; Dhital, Sushil; Wu, Peng; Gidley, Michael J; Fox, Glen P; Gilbert, Robert G

    2018-02-15

    The conversion of barley starch to sugars is a complex enzymic process. Most previous work concerned the biotechnical aspect of in situ barley enzymes. However, the interactions among the macromolecular substrates and their effects on enzymic catalysis has been little examined. Here, we explore the mechanisms whereby interactions of protein and starch in barley flour affect the kinetics of enzymatic hydrolysis of starch in an in vitro system, using digestion rate data and structural analysis by confocal microscopy. The degradation kinetics of both uncooked barley flour and of purified starches are found to be two-step sequential processes. Barley proteins, especially the water-soluble component, are found to retard the digestion of starch degraded by α-amylase: the enzyme binds with water-insoluble protein and with starch granules, leading to reduced starch hydrolysis. These findings are of potential industrial value in both the brewing and food industries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. 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.

  18. Sixth taste – starch taste?

    Directory of Open Access Journals (Sweden)

    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.

  19. 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 ...

  20. Biosynthesis of tylophora alkaloids

    International Nuclear Information System (INIS)

    Mulchandani, N.B.; Iyer, S.S.; Badheka, L.P.

    1974-01-01

    Using labelled precursors, biosynthesis of the tylophora alkaloids, tylophorine, tylophorinidine and tylophorinide has been investigated in Tylophora asthmatica plants. The radioactive precursors, phenylalanine-2- 14 C, benzoic acid-1- 14 C, benzoic acid-ring 14 C, acetate-2- 14 C, ornithine-5- 14 C, acetate-2- 14 C, ornithine-5- 14 C and cinnamic acid-2- 14 C were administered to the plants individually by wick technique. Tylophorine was isolated in each case and assayed for its radioactivity to find out the incorporation of the label into it. The results indicate that: (1) phenylalanine via cinnamic acid is an important precursor in the biosynthesis of tylophorine (2) orinithine participates in tylophorine biosynthesis via pyrroline and (3) tylophorinidine may be a direct precursor of tylophorine. (M.G.B.)

  1. Poly(Lactic Acid) Filled with Cassava Starch-g-Soybean Oil Maleate

    Science.gov (United States)

    Kiangkitiwan, Nopparut; Srikulkit, Kawee

    2013-01-01

    Poly(lactic acid), PLA, is a biodegradable polymer, but its applications are limited by its high cost and relatively poorer properties when compared to petroleum-based plastics. The addition of starch powder into PLA is one of the most promising efforts because starch is an abundant and cheap biopolymer. However, the challenge is the major problem associated with poor interfacial adhesion between the hydrophilic starch granules and the hydrophobic PLA, leading to poorer mechanical properties. In this paper, soybean oil maleate (SOMA) was synthesized by grafting soybean oil with various weight percents of maleic anhydride (MA) using dicumyl peroxide (DCP) as an initiator. Then, SOMA was employed for the surface modifying of cassava starch powder, resulting in SOMA-g-STARCH. The obtained SOMA-g-STARCH was mixed with PLA in various weight ratios using twin-screw extruder, resulting in PLA/SOMA-g-STARCH. Finally, the obtained PLA/SOMA-g-STARCH composites were prepared by a compression molding machines. The compatibility, thermal properties, morphology properties, and mechanical properties were characterized and evaluated. The results showed that the compatibility, surface appearance, and mechanical properties at 90 : 10 and 80 : 20 ratios of PLA/SOMA-g-STARCH were the best. PMID:24307883

  2. Modified Starch-Chitosan Edible Films: Physicochemical and Mechanical Characterization

    Directory of Open Access Journals (Sweden)

    Monserrat Escamilla-García

    2017-12-01

    Full Text Available Starch and chitosan are widely used for preparation of edible films that are of great interest in food preservation. This work was aimed to analyze the relationship between structural and physical properties of edible films based on a mixture of chitosan and modified starches. In addition, films were tested for antimicrobial activity against Listeria innocua. Films were prepared by the casting method using chitosan (CT, waxy (WS, oxidized (OS and acetylated (AS corn starches and their mixtures. The CT-starches films showed improved barrier and mechanical properties as compared with those made from individual components, CT-OS film presented the lowest thickness (74 ± 7 µm, water content (11.53% ± 0.85%, w/w, solubility (26.77% ± 1.40%, w/v and water vapor permeability ((1.18 ± 0.48 × 10−9 g·s−1·m−1·Pa−1. This film showed low hardness (2.30 ± 0.19 MPa, low surface roughness (Rq = 3.20 ± 0.41 nm and was the most elastic (Young’s modulus = 0.11 ± 0.06 GPa. In addition, films made from CT-starches mixtures reduced CT antimicrobial activity against L. innocua, depending on the type of modified starch. This was attributed to interactions between acetyl groups of AS with the carbonyl and amino groups of CT, leaving CT with less positive charge. Interaction of the pyranose ring of OS with CT led to increased OH groups that upon interaction with amino groups, decreased the positive charge of CT, and this effect is responsible for the reduced antimicrobial activity. It was found that the type of starch modification influenced interactions with chitosan, leading to different films properties.

  3. Pyrophosphate levels strongly influence ascorbate and starch content in tomato fruit

    Directory of Open Access Journals (Sweden)

    Sonia eOsorio

    2013-08-01

    Full Text Available Ascorbate (vitamin C deficiency leads to low immunity, scurvy, and other human diseases and is therefore a global health problem. Given that plants are major ascorbate sources for humans, biofortification of this vitamin in our foodstuffs is of considerable importance. Ascorbate is synthetized by a number of alternative pathways: (i from the glycolytic intermediates D-glucose-6P (the key intermediates are GDP-D-mannose and L-galactose, (ii from the breakdown of the cell wall polymer pectin which uses the methyl ester of D-galacturonic acid as precursor and (iii from myo-inositol as precursor via myo-inositol oxygenase. We report here the engineering of fruit-specific overexpression of a bacterial pyrophosphatase, which hydrolyzes the inorganic pyrophosphate (PPi to orthophosphate (Pi. This strategy resulted in increased vitamin C levels up to 2.5 fold in ripe fruit as well as increasing in the major sugars, sucrose and glucose, yet decreasing the level of starch. When considered together, these finding indicate an intimate linkage between ascorbate and sugar biosynthesis in plants. Moreover, the combined data reveal the importance of PPi metabolism in tomato fruit metabolism and development.

  4. Mutation of Rice BC12/GDD1, Which Encodes a Kinesin-Like Protein That Binds to a GA Biosynthesis Gene Promoter, Leads to Dwarfism with Impaired Cell Elongation[W][OA

    Science.gov (United States)

    Li, Juan; Jiang, Jiafu; Qian, Qian; Xu, Yunyuan; Zhang, Cui; Xiao, Jun; Du, Cheng; Luo, Wei; Zou, Guoxing; Chen, Mingluan; Huang, Yunqing; Feng, Yuqi; Cheng, Zhukuan; Yuan, Ming; Chong, Kang

    2011-01-01

    The kinesins are a family of microtubule-based motor proteins that move directionally along microtubules and are involved in many crucial cellular processes, including cell elongation in plants. Less is known about kinesins directly regulating gene transcription to affect cellular physiological processes. Here, we describe a rice (Oryza sativa) mutant, gibberellin-deficient dwarf1 (gdd1), that has a phenotype of greatly reduced length of root, stems, spikes, and seeds. This reduced length is due to decreased cell elongation and can be rescued by exogenous gibberellic acid (GA3) treatment. GDD1 was cloned by a map-based approach, was expressed constitutively, and was found to encode the kinesin-like protein BRITTLE CULM12 (BC12). Microtubule cosedimentation assays revealed that BC12/GDD1 bound to microtubules in an ATP-dependent manner. Whole-genome microarray analysis revealed the expression of ent-kaurene oxidase (KO2), which encodes an enzyme involved in GA biosynthesis, was downregulated in gdd1. Electrophoretic mobility shift and chromatin immunoprecipitation assays revealed that GDD1 bound to the element ACCAACTTGAA in the KO2 promoter. In addition, GDD1 was shown to have transactivation activity. The level of endogenous GAs was reduced in gdd1, and the reorganization of cortical microtubules was altered. Therefore, BC12/GDD1, a kinesin-like protein with transcription regulation activity, mediates cell elongation by regulating the GA biosynthesis pathway in rice. PMID:21325138

  5. Synthesis and properties of fatty acid starch esters.

    Science.gov (United States)

    Winkler, Henning; Vorwerg, Waltraud; Wetzel, Hendrik

    2013-10-15

    Being completely bio-based, fatty acid starch esters (FASEs) are attractive materials that represent an alternative to crude oil-based plastics. In this study, two synthesis methods were compared in terms of their efficiency, toxicity and, especially, product solubility with starch laurate (C12) as model compound. Laurates (DS>2) were obtained through transesterification of fatty acid vinylesters in DMSO or reaction with fatty acid chlorides in pyridine. The latter lead to higher DS-values in a shorter reaction time. But due to the much better solubility of the products compared to lauroyl chloride esterified ones, vinylester-transesterification was preferred to optimize reaction parameters, where reaction time could be shortened to 2h. FASEs C6-C18 were also successfully prepared via transesterification. To determine the DS of the resulting starch laurates, the efficient ATR-IR method was compared with common methods (elementary analysis, (1)H NMR). Molar masses (Mw) of the highly soluble starch laurates were analyzed using SEC-MALLS (THF). High recovery rates (>80%) attest to the outstanding solubility of products obtained through transesterification, caused by a slight disintegration during synthesis. Particle size distributions (DLS) demonstrated stable dissolutions in CHCl3 of vinyl laurate esterified - contrary to lauroyl chloride esterified starch. For all highly soluble FASEs (C6-C18), formation of concentrated solutions (10 wt%) is feasible. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Change of microflora of two starch samples by gamma irradiation

    International Nuclear Information System (INIS)

    Fretton, R.; Fretton, J.; Delattre, J.M.

    1975-01-01

    Starch is the basic component of a larger number of manufactured foods. The disinfection of such a powder by 60 Co is studied here. Gamma irradiation of two starch samples with different degrees of contamination allows the assumption that, in most cases, good radio-pasteurization can be achieved with 300 krad. The radio-pasteurization doses (varying from 300 to 600 krad) are a function of the initial contamination. Irradiation effects are spectacular with moulds. Activation of spores of some Clostridium species leads us to recommend an irradiation level higher than 200 krad. The most resistant organisms to gamma irradiation are the aerobic and anaerobic sporulated bacteria. The thermophilic forms are the most important. Spores of Bacillus, chiefly Bacillus licheniformis and Bacillus brevis, are the most frequent bacteria. Storage of irradiated starch at room temperature has little effect upon the number of revivable survivors. (orig.) [de

  7. 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.

  8. 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.

  9. Two carbon fluxes to reserve starch in potato (Solanum tuberosum L.) tuber cells are closely interconnected but differently modulated by temperature.

    Science.gov (United States)

    Fettke, Joerg; Leifels, Lydia; Brust, Henrike; Herbst, Karoline; Steup, Martin

    2012-05-01

    Parenchyma cells from tubers of Solanum tuberosum L. convert several externally supplied sugars to starch but the rates vary largely. Conversion of glucose 1-phosphate to starch is exceptionally efficient. In this communication, tuber slices were incubated with either of four solutions containing equimolar [U-¹⁴C]glucose 1-phosphate, [U-¹⁴C]sucrose, [U-¹⁴C]glucose 1-phosphate plus unlabelled equimolar sucrose or [U-¹⁴C]sucrose plus unlabelled equimolar glucose 1-phosphate. C¹⁴-incorporation into starch was monitored. In slices from freshly harvested tubers each unlabelled compound strongly enhanced ¹⁴C incorporation into starch indicating closely interacting paths of starch biosynthesis. However, enhancement disappeared when the tubers were stored. The two paths (and, consequently, the mutual enhancement effect) differ in temperature dependence. At lower temperatures, the glucose 1-phosphate-dependent path is functional, reaching maximal activity at approximately 20 °C but the flux of the sucrose-dependent route strongly increases above 20 °C. Results are confirmed by in vitro experiments using [U-¹⁴C]glucose 1-phosphate or adenosine-[U-¹⁴C]glucose and by quantitative zymograms of starch synthase or phosphorylase activity. In mutants almost completely lacking the plastidial phosphorylase isozyme(s), the glucose 1-phosphate-dependent path is largely impeded. Irrespective of the size of the granules, glucose 1-phosphate-dependent incorporation per granule surface area is essentially equal. Furthermore, within the granules no preference of distinct glucosyl acceptor sites was detectable. Thus, the path is integrated into the entire granule biosynthesis. In vitro C¹⁴C-incorporation into starch granules mediated by the recombinant plastidial phosphorylase isozyme clearly differed from the in situ results. Taken together, the data clearly demonstrate that two closely but flexibly interacting general paths of starch biosynthesis are functional

  10. 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 ...

  11. Glycopeptide antibiotic biosynthesis.

    Science.gov (United States)

    Yim, Grace; Thaker, Maulik N; Koteva, Kalinka; Wright, Gerard

    2014-01-01

    Glycopeptides such as vancomycin, teicoplanin and telavancin are essential for treating infections caused by Gram-positive bacteria. Unfortunately, the dwindled pipeline of new antibiotics into the market and the emergence of glycopeptide-resistant enterococci and other resistant bacteria are increasingly making effective antibiotic treatment difficult. We have now learned a great deal about how bacteria produce antibiotics. This information can be exploited to develop the next generation of antimicrobials. The biosynthesis of glycopeptides via nonribosomal peptide assembly and unusual amino acid synthesis, crosslinking and tailoring enzymes gives rise to intricate chemical structures that target the bacterial cell wall. This review seeks to describe recent advances in our understanding of both biosynthesis and resistance of these important antibiotics.

  12. Redox Impact on Starch Biosynthetic Enzymes in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Skryhan, Katsiaryna

    Summary The thesis provides new insight into the influence of the plant cell redox state on the transient starch metabolism in Arabidopsis thaliana with a focus on starch biosynthetic enzymes. Two main hypotheses forms the basis of this thesis: 1) photosynthesis and starch metabolism are coordina......Summary The thesis provides new insight into the influence of the plant cell redox state on the transient starch metabolism in Arabidopsis thaliana with a focus on starch biosynthetic enzymes. Two main hypotheses forms the basis of this thesis: 1) photosynthesis and starch metabolism...... are coordinated by the redox state of the cell via post-translational modification of the starch metabolic enzymes containing redox active cysteine residues and these cysteine residues became cross-linked upon oxidation providing a conformational change leading to activity loss; 2) cysteine residues...... of chloroplast enzymes can play a role not only in enzyme activity and redox sensitivity but also in protein folding and stability upon oxidation. Several redox sensitive enzymes identified in this study can serve as potential targets to control the carbon flux to and from starch during the day and night...

  13. Physicochemical characterization of starches from seven improved ...

    African Journals Online (AJOL)

    SARAH

    2014-01-31

    Jan 31, 2014 ... Key words: Cassava, starch, functional properties, industrial utilization. ... in demand for starch (Davis et al., 2002). Potato, maize, wheat and cassava are the major ... ambient temperature and stored at 4 °C for 4 weeks.

  14. 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.

  15. In vivo quantification of plant starch reserves at micrometer resolution using X-ray microCT imaging and machine learning.

    Science.gov (United States)

    Earles, J Mason; Knipfer, Thorsten; Tixier, Aude; Orozco, Jessica; Reyes, Clarissa; Zwieniecki, Maciej A; Brodersen, Craig R; McElrone, Andrew J

    2018-03-08

    Starch is the primary energy storage molecule used by most terrestrial plants to fuel respiration and growth during periods of limited to no photosynthesis, and its depletion can drive plant mortality. Destructive techniques at coarse spatial scales exist to quantify starch, but these techniques face methodological challenges that can lead to uncertainty about the lability of tissue-specific starch pools and their role in plant survival. Here, we demonstrate how X-ray microcomputed tomography (microCT) and a machine learning algorithm can be coupled to quantify plant starch content in vivo, repeatedly and nondestructively over time in grapevine stems (Vitis spp.). Starch content estimated for xylem axial and ray parenchyma cells from microCT images was correlated strongly with enzymatically measured bulk-tissue starch concentration on the same stems. After validating our machine learning algorithm, we then characterized the spatial distribution of starch concentration in living stems at micrometer resolution, and identified starch depletion in live plants under experimental conditions designed to halt photosynthesis and starch production, initiating the drawdown of stored starch pools. Using X-ray microCT technology for in vivo starch monitoring should enable novel research directed at resolving the spatial and temporal patterns of starch accumulation and depletion in woody plant species. No claim to original US Government works New Phytologist © 2018 New Phytologist Trust.

  16. Effect of starch isolation method on properties of sweet potato starch

    Directory of Open Access Journals (Sweden)

    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.

  17. ( 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 ...

  18. 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.

  19. 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  2. Effect of carboxymethyl cellulose concentration on physical properties of biodegradable cassava starch-based films

    Directory of Open Access Journals (Sweden)

    Sriburi Pensiri

    2011-02-01

    Full Text Available Abstract Background Cassava starch, the economically important agricultural commodity in Thailand, can readily be cast into films. However, the cassava starch film is brittle and weak, leading to inadequate mechanical properties. The properties of starch film can be improved by adding plasticizers and blending with the other biopolymers. Results Cassava starch (5%w/v based films plasticized with glycerol (30 g/100 g starch were characterized with respect to the effect of carboxymethyl cellulose (CMC concentrations (0, 10, 20, 30 and 40%w/w total solid and relative humidity (34 and 54%RH on the mechanical properties of the films. Additionally, intermolecular interactions were determined by Fourier transform infrared spectroscopy (FT-IR, melting temperature by differential scanning calorimetry (DSC, and morphology by scanning electron microscopy (SEM. Water solubility of the films was also determined. Increasing concentration of CMC increased tensile strength, reduced elongation at break, and decreased water solubility of the blended films. FT-IR spectra indicated intermolecular interactions between cassava starch and CMC in blended films by shifting of carboxyl (C = O and OH groups. DSC thermograms and SEM micrographs confirmed homogeneity of cassava starch-CMC films. Conclusion The addition of CMC to the cassava starch films increased tensile strength and reduced elongation at break of the blended films. This was ascribed to the good interaction between cassava starch and CMC. Cassava starch-CMC composite films have the potential to replace conventional packaging, and the films developed in this work are suggested to be suitable for low moisture food and pharmaceutical products.

  3. 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.

  4. Triterpene biosynthesis in plants.

    Science.gov (United States)

    Thimmappa, Ramesha; Geisler, Katrin; Louveau, Thomas; O'Maille, Paul; Osbourn, Anne

    2014-01-01

    The triterpenes are one of the most numerous and diverse groups of plant natural products. They are complex molecules that are, for the most part, beyond the reach of chemical synthesis. Simple triterpenes are components of surface waxes and specialized membranes and may potentially act as signaling molecules, whereas complex glycosylated triterpenes (saponins) provide protection against pathogens and pests. Simple and conjugated triterpenes have a wide range of applications in the food, health, and industrial biotechnology sectors. Here, we review recent developments in the field of triterpene biosynthesis, give an overview of the genes and enzymes that have been identified to date, and discuss strategies for discovering new triterpene biosynthetic pathways.

  5. Kinetic modeling and exploratory numerical simulation of chloroplastic starch degradation

    Directory of Open Access Journals (Sweden)

    Nag Ambarish

    2011-06-01

    Full Text Available Abstract Background Higher plants and algae are able to fix atmospheric carbon dioxide through photosynthesis and store this fixed carbon in large quantities as starch, which can be hydrolyzed into sugars serving as feedstock for fermentation to biofuels and precursors. Rational engineering of carbon flow in plant cells requires a greater understanding of how starch breakdown fluxes respond to variations in enzyme concentrations, kinetic parameters, and metabolite concentrations. We have therefore developed and simulated a detailed kinetic ordinary differential equation model of the degradation pathways for starch synthesized in plants and green algae, which to our knowledge is the most complete such model reported to date. Results Simulation with 9 internal metabolites and 8 external metabolites, the concentrations of the latter fixed at reasonable biochemical values, leads to a single reference solution showing β-amylase activity to be the rate-limiting step in carbon flow from starch degradation. Additionally, the response coefficients for stromal glucose to the glucose transporter kcat and KM are substantial, whereas those for cytosolic glucose are not, consistent with a kinetic bottleneck due to transport. Response coefficient norms show stromal maltopentaose and cytosolic glucosylated arabinogalactan to be the most and least globally sensitive metabolites, respectively, and β-amylase kcat and KM for starch to be the kinetic parameters with the largest aggregate effect on metabolite concentrations as a whole. The latter kinetic parameters, together with those for glucose transport, have the greatest effect on stromal glucose, which is a precursor for biofuel synthetic pathways. Exploration of the steady-state solution space with respect to concentrations of 6 external metabolites and 8 dynamic metabolite concentrations show that stromal metabolism is strongly coupled to starch levels, and that transport between compartments serves to

  6. Maize starch biphasic pasting curves

    CSIR Research Space (South Africa)

    Nelles, EM

    2000-05-01

    Full Text Available (150–500 rev/min). The second pasting peak is attributed to the formation of complexes between amylose and low levels of lipid present in maize starch. When lipid was partially removed by extraction with methanol-chloroform (1: 3 v/v), the second...

  7. 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.

  8. 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.

  9. Cassava starch in the Brazilian food industry

    Directory of Open Access Journals (Sweden)

    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.

  10. 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.

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

    Science.gov (United States)

    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.

  12. 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.

  13. 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.

  14. Cariogenicity of soluble starch in oral in vitro biofilm and experimental rat caries studies: a comparison.

    Science.gov (United States)

    Thurnheer, T; Giertsen, E; Gmür, R; Guggenheim, B

    2008-09-01

    Common belief suggests that starch is less cariogenic than sugar; however, the related literature is quite controversial. We aimed to compare cariogenic and microbiological effects of soluble starch in both a standard animal model and an oral biofilm system, and to assess the possible substitution of the animal model. Six-species biofilms were grown anaerobically on enamel discs in saliva and medium with glucose/sucrose, starch (average molecular weight of 5000, average polymerization grade of 31), or mixtures thereof. After 64.5 h of biofilm formation, the microbiota were quantitated by cultivation and demineralization was measured by quantitative light-induced fluorescence. To assess caries incidence in rats, the same microbiota as in the biofilm experiments were applied. The animals were fed diets containing either glucose, glucose/sucrose, glucose/sucrose/starch or starch alone. Results with both models show that demineralization was significantly smaller with starch than sucrose. The data demonstrate that soluble starch is substantially less cariogenic than glucose/sucrose. By leading to the same scientific evidence as its in vivo counterpart, the described in vitro biofilm system provides an interesting and valuable tool in the quest to reduce experimentation with animals.

  15. Calcium modified edible Canna (Canna edulis L) starch for controlled released matrix

    Science.gov (United States)

    Putri, A. P.; Ridwan, M.; Darmawan, T. A.; Darusman, F.; Gadri, A.

    2017-07-01

    Canna edulis L starch was modified with calcium chloride in order to form controlled released matrix. Present study aim to analyze modified starch characteristic. Four different formulation of ondansetron granules was used to provide dissolution profile of controlled released, two formula consisted of 15% and 30% modified starch, one formula utilized matrix reference standards and the last granules was negative control. Methocel-hydroxypropyl methyl cellulose was used as controlled released matrix reference standards in the third formula. Calcium starch was synthesized in the presence of sodium hydroxide to form gelatinized mass and calcium chloride as the cross linking agent. Physicochemical and dissolution properties of modified starch for controlled released application were investigated. Modified starch has higher swelling index, water solubility and compressibility index. Three of four different formulation of granules provide dissolution profile of controlled released. The profiles indicate granules which employed calcium Canna edulis L starch as matrix are able to resemble controlled drug released profile of matrix reference, however their bigger detain ability lead to lower bioavailability.

  16. 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.

  17. 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 ...

  18. Effect of starch as hydrocolloids for formation of a stable emulsion system in food

    Directory of Open Access Journals (Sweden)

    O. Lugovska

    2015-05-01

    Full Text Available Іntroduction. It is necessary to determine the effect of the physicochemical properties of native and modified starches in their use in food. Matherials and methods. Investigated two samples of food emulsions using starches of different nature of origin (native, modified starch. Using laboratory balances, volume of cylinders determined percentage of water separation during freezing and unfreezing emulsions; Brukfild viscometer measured the viscosity increase depending on the time, temperature and pH of food emulsions. Results. When freezing / unfreezing emulsion of native starch in the first cycle of water has been separated by 8% in the second cycle of 38%, the third 50%, in contrast to the emulsion with modified starch water separation starts from the fourth cycle slightly, in the fifth cycle percentage of water separation is 1%, the sixth cycle of 3 %. As a result, studies of viscosity versus time, temperature and pH of food emulsions proved that in an acidic medium at pH 6.5 viscosity emulsion with modified starch is stored and then increases over a longer time compared with the emulsion of native starch where the viscosity at the beginning of the storage period increases and then decreases. Conclusions. Investigated the properties of native starch in the emulsion show that their use in industrial processes can lead to blockage of the heat exchanger, and the viscosity of the output of the production process is unpredictable and varies greatly depending on the combination of temperature and mechanical stress. It makes use in the manufacture of modified starches that combines a combination of two types of modifications: stabilization and crosslinking.

  19. 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...

  20. 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)

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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

  6. Chemically Modified Starch; Allyl- and Epoxy-Starch Derivatives: Their Synthesis and Characterization

    NARCIS (Netherlands)

    Franssen, M.C.R.; Boeriu, C.

    2014-01-01

    Both native and modified starches, such as starch that is pregelatinized, extruded, acid-converted, cross-linked, and substituted, are widely used in industry. This chapter describes a mild two-step process for the synthesis of novel, highly reactive granular epoxy-starch derivatives. Via this

  7. 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.

  8. 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 ...

  9. 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...

  10. 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.

  11. 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...

  12. 46_ _267 - 278__Aminu- Biosynthesis

    African Journals Online (AJOL)

    User

    ISSN 2006 – 6996. BIOSYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL STUDY OF .... the excitation of surface Plasmon vibration with. AgNPs. ... Thin films of the sample were prepared on a carbon ... The resulting film on the SEM.

  13. Biosynthesis of Gold Nanoparticles Using Pseudomonas Aeruginosa

    International Nuclear Information System (INIS)

    Abd El-Aziz, M.; Badr, Y.; Mahmoud, M. A.

    2007-01-01

    Pseudomonas aeruginosa were used for extracellular biosynthesis of gold nanoparticles (Au NPs). Consequently, Au NPs were formed due to reduction of gold ion by bacterial cell supernatant of P. aeruginos ATCC 90271, P. aeruginos (2) and P. aeruginos (1). The UV-Vis. and fluorescence spectra of the bacterial as well as chemical prepared Au NPs were recorded. Transmission electron microscopy (TEM) micrograph showed the formation of well-dispersed gold nanoparticles in the range of 15-30 nm. The process of reduction being extracellular and may lead to the development of an easy bioprocess for synthesis of Au NPs

  14. 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.

  15. Biosynthesis of oleamide.

    Science.gov (United States)

    Mueller, Gregory P; Driscoll, William J

    2009-01-01

    Oleamide (cis-9-octadecenamide) is the prototype long chain primary fatty acid amide lipid messenger. The natural occurrence of oleamide was first reported in human serum in 1989. Subsequently oleamide was shown to accumulate in the cerebrospinal fluid of sleep-deprived cats and to induce sleep when administered to experimental animals. Accordingly, oleamide first became known for its potential role in the mechanisms that mediate the drive to sleep. Oleamide also has profound effects on thermoregulation and acts as an analgesic in several models of experimental pain. Although these important pharmacologic effects are well establish, the biochemical mechanism for the synthesis of oleamide has not yet been defined. This chapter reviews the biosynthetic pathways that have been proposed and highlights two mechanisms which are most supported by experimental evidence: the generation of oleamide from oleoylglycine by the neuropeptide processing enzyme, peptidylglycine alpha-amidating monooxygenase (PAM), and alternatively, the direct amidation of oleic acid via oleoyl coenzyme A by cytochrome c using ammonia as the nitrogen source. The latter mechanism is discussed in the context of apoptosis where oleamide may play a role in regulating gap junction communication. Lastly, several considerations and caveats pertinent to the future study oleamide biosynthesis are discussed.

  16. Glycolipid biosynthesis in cyanobacteria

    International Nuclear Information System (INIS)

    Van Dusen, W.J.; Jaworski, J.G.

    1987-01-01

    The biosynthesis of monogalactosyldiacyl-glycerol (MGDG) was studied in five different cyanobacteria. Previous work has shown Anabaena variabilis to synthesize both MGDG and monoglucosyl-diacylglycerol (MG1cDG) with MG1cDG being the precursor of MGDG. They have examined four other cyanobacteria to determine if a similar relationship exists. The cyanobacteria studied were Anabaena variabilis, Chlorogloeopsis sp., Schizothrix calcicola, Anacystis nidulans, and Anacystis marina. Each were grown in liquid culture and lipids were labeled with 14 C]CO 2 for 20 min., 1.0 hr, 1.0 hr + 10 hr chase. Glycolipids were analyzed by initial separation of MGDG and MG1cDG by TLC followed by further analysis by HPLC. Complete separation of molecular species was obtained isocratically on an ODS column. All of the cyanobacteria labeled 16-C and 18-C fatty acids except for A. marina which labeled only 14-C and 16-C fatty acids. Desaturation of the fatty acids could be observed in the 1.0 hr and chase experiments. All were capable of labeling both MG1cDG and MGDG with the precursor-product relationship being observed. There does not appear to be a direct relationship between the epimerization of the sugar moiety and fatty acid desaturation

  17. 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.

  18. Fructan biosynthesis and degradation as part of plant metabolism controlling sugar fluxes during durum wheat kernel maturation

    Directory of Open Access Journals (Sweden)

    Sara eCimini

    2015-02-01

    Full Text Available Wheat kernels contain fructans, fructose based oligosaccharides with prebiotic properties, in levels between 2 and 35 weight % depending on the developmental stage of the kernel. To improve knowledge on the metabolic pathways leading to fructan storage and degradation, carbohydrate fluxes occurring during durum wheat kernel development were analyzed. Kernels were collected at various developmental stages and quali-quantitative analysis of carbohydrates (mono- and di-saccharides, fructans, starch was performed, alongside analysis of the activities and gene expression of the enzymes involved in their biosynthesis and hydrolysis. High resolution HPAEC-PAD of fructan contained in durum wheat kernels revealed that fructan content is higher at the beginning of kernel development, when fructans with higher DP, such as bifurcose and 1,1-nystose, were mainly found. The changes in fructan pool observed during kernel maturation might be part of the signaling pathways influencing carbohydrate metabolism and storage in wheat kernels during development. During the first developmental stages fructan accumulation may contribute to make kernels more effective Suc sinks and to participate in osmotic regulation while the observed decrease in their content may mark the transition to later developmental stages, transition that is also orchestrated by changes in redox balance.

  19. 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

  20. 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.

  1. Semicontinuous saccharification of starch in alcohol production

    Energy Technology Data Exchange (ETDEWEB)

    Danilyak, N.I.; Kaminskil, R.S.; Shvedov, A.D.

    1959-05-21

    The saccharification is accomplished with an enzyme preparation of Aspergillus oryzae. In the first stage, the starch is treated at 57 to 59/sup 0/ with a fermenting solution containing 1% enzyme based on the starch content. The second step is carried out in the fermenting solution containing 2.5% enzyme.

  2. Starch and cellulose nanocrystals together into thermoplastic starch bionanocomposites.

    Science.gov (United States)

    González, Kizkitza; Retegi, Aloña; González, Alba; Eceiza, Arantxa; Gabilondo, Nagore

    2015-03-06

    In the present work, thermoplastic maize starch based bionanocomposites were prepared as transparent films, plasticized with 35% of glycerol and reinforced with both waxy starch (WSNC) and cellulose nanocrystals (CNC), previously extracted by acidic hydrolysis. The influence of the nanofiller content was evaluated at 1 wt.%, 2.5 wt.% and 5 wt.% of WSNC. The effect of adding the two different nanoparticles at 1 wt.% was also investigated. As determined by tensile measurements, mechanical properties were improved at any composition of WSNC. Water vapour permeance values maintained constant, whereas barrier properties to oxygen reduced in a 70%, indicating the effectiveness of hydrogen bonding at the interphase. The use of CNC or CNC and WSNC upgraded mechanical results, but no significant differences in barrier properties were obtained. A homogeneous distribution of the nanofillers was demonstrated by atomic force microscopy, and a shift of the two relaxation peaks to higher temperatures was detected by dynamic mechanical analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. 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.

  4. [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.

  5. 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.

  6. Modification of the microstructure of the films formed by gamma irradiated starch examined by SEM

    Science.gov (United States)

    Cieśla, K.; Sartowska, B.

    2016-01-01

    The paper concerns the effect of gamma irradiation carried out for starch on the microstructure of the films prepared using the starch and its composition with sodium laurate (NaLau) and cetyltrimethylammonium bromide (CTAB) studied by scanning electron microscopy (SEM). Potato starch was irradiated with 60Co gamma rays applying a dose of 30 kGy. Films were prepared by the solution casting method with the addition of 30 wt% glycerol as a plasticizer. Films containing NaLau and CTAB were prepared after performing the procedure, leading to starch-surfactant complexes. Mechanical tests and wetting angle measurements were performed for the films. SEM observations were carried out for the surfaces, fractures and/or sections of the films subjected to chemical fixation and for the dried films. The films obtained using irradiated starch are characterized by a smoother and more homogeneous structure as compared to those based on the non-irradiated starch. Besides, a number of small precipitates were observed on the films surfaces after drying and the number of those precipitates seemed to be higher after irradiation. The results can be related to differences in the microstructure of gels formed on the intermediate step of the films preparation and to the presence of two phases in the system and might serve for explanation of the radiation induced improvement of the hydrophilic/hydrophobic properties, a modification of the mechanical properties of the films, as well as for the changes of those properties resulting after storage.

  7. Preparation and properties of novel melt-blended halloysite nanotubes/wheat starch nanocomposites.

    Science.gov (United States)

    Schmitt, H; Prashantha, K; Soulestin, J; Lacrampe, M F; Krawczak, P

    2012-07-01

    Novel bionanocomposites based on halloysite nanotubes as nanofillers and plasticized starch as polymeric matrix were successfully prepared by melt-extrusion for the first time. Both modified and non modified halloysites were added at different weight contents. The structural, morphological, thermal and mechanical properties of plasticized starch/halloysites nanocomposites were investigated. Melt-compounding appears to be a suitable process to uniformly disperse nanotubes in the plasticized starch matrix. Interactions between plasticized starch and halloysites in the nanocomposites and microstructure modifications were monitored using Fourier transfer infrared spectroscopy, X-ray diffraction and dynamic mechanical analysis. Addition of halloysite nanotubes slightly enhances the thermal stability of starch (onset temperature of degradation delayed to higher temperatures). The tensile mechanical properties of starch are also significantly improved (up to +144% for Young's modulus and up to +29% for strength) upon addition of both modified and unmodified halloysites, interestingly without loss of ductility. Modified halloysites lead to significantly higher Young's modulus than unmodified halloysites. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. 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.

  9. Essences in Metabolic Engineering of Lignan Biosynthesis

    Directory of Open Access Journals (Sweden)

    Honoo Satake

    2015-05-01

    Full Text Available Lignans are structurally and functionally diverse phytochemicals biosynthesized in diverse plant species and have received wide attentions as leading compounds of novel drugs for tumor treatment and healthy diets to reduce of the risks of lifestyle-related non-communicable diseases. However, the lineage-specific distribution and the low-amount of production in natural plants, some of which are endangered species, hinder the efficient and stable production of beneficial lignans. Accordingly, the development of new procedures for lignan production is of keen interest. Recent marked advances in the molecular and functional characterization of lignan biosynthetic enzymes and endogenous and exogenous factors for lignan biosynthesis have suggested new methods for the metabolic engineering of lignan biosynthesis cascades leading to the efficient, sustainable, and stable lignan production in plants, including plant cell/organ cultures. Optimization of light conditions, utilization of a wide range of elicitor treatments, and construction of transiently gene-transfected or transgenic lignan-biosynthesizing plants are mainly being attempted. This review will present the basic and latest knowledge regarding metabolic engineering of lignans based on their biosynthetic pathways and biological activities, and the perspectives in lignan production via metabolic engineering.

  10. Genes encoding enzymes of the lignin biosynthesis pathway in Eucalyptus

    Directory of Open Access Journals (Sweden)

    Ricardo Harakava

    2005-01-01

    Full Text Available Eucalyptus ESTs libraries were screened for genes involved in lignin biosynthesis. This search was performed under the perspective of recent revisions on the monolignols biosynthetic pathway. Eucalyptus orthologues of all genes of the phenylpropanoid pathway leading to lignin biosynthesis reported in other plant species were identified. A library made with mRNAs extracted from wood was enriched for genes involved in lignin biosynthesis and allowed to infer the isoforms of each gene family that play a major role in wood lignin formation. Analysis of the wood library suggests that, besides the enzymes of the phenylpropanoids pathway, chitinases, laccases, and dirigent proteins are also important for lignification. Colocalization of several enzymes on the endoplasmic reticulum membrane, as predicted by amino acid sequence analysis, supports the existence of metabolic channeling in the phenylpropanoid pathway. This study establishes a framework for future investigations on gene expression level, protein expression and enzymatic assays, sequence polymorphisms, and genetic engineering.

  11. 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.

  12. 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.

  13. 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.

  14. 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 ...

  15. Process optimization for a potent wild and mutant strain of aspergillus niger for biosynthesis of amyloglucosidase

    International Nuclear Information System (INIS)

    Malik, S.; Haq, I.U.; Iftikhar, T.

    2011-01-01

    The present study is concerned with the selection of a potent strain of Aspergillus niger and optimization of the cultural conditions for the biosynthesis of amyloglucosidase. The cultural conditions were optimized for the enzyme production. Twenty percent (50/250ml flask) was found to be optimum volume of the medium. Optimum temperature was 30 deg. C after 72 h of incubation, with the initial pH of the medium 5.0. 2% Starch with 1% glucose as an additional carbon source gave maximum amyloglucosidase production Addition of 0.3% ammonium sulphate in the fermentation medium increased the enzyme production while 2% spore inoculum showed best amyloglucosidase production. (author)

  16. 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.

  17. 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.

  18. Biosynthesis of silver nanoparticles synthesized by Aspergillus ...

    Indian Academy of Sciences (India)

    Biotechnology Division, Applied Science Department, University of ... Abstract. In the present study, biosynthesis of silver nanoparticles and its antioxidant, antimicrobial and cytotoxic ... example of the biosynthesis using fungi was that the cell-.

  19. TECHNOLOGY OF THERMOPLASTIC STARCH PRODUCTION

    Directory of Open Access Journals (Sweden)

    N. D. Lukin

    2015-01-01

    Full Text Available In recent years, the manufacturing of bio-recyclable polymer products, which production and consumption has become an efficient way to protect environment from solid wastes in different countries of the world. The issue of environmental protection becomes global and the rapid growth of synthetic plastics application in many industries is a serious concern. There is a important task to improve the quality, safety and durability of products as well as their utilization after the expiration period. One of the most acceptable ways to solve these issues is to produce biodegradable materials based on natural materials, which are not harmful for environment and human health. A very common and effective method to give biological degradability to synthetic polymers is to insert starch into polymer composition in combination with other ingredients.

  20. 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.

  1. 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.

  2. 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.

  3. A titration approach to identify the capacity for starch digestion in milk-fed calves.

    Science.gov (United States)

    Gilbert, M S; van den Borne, J J G C; Berends, H; Pantophlet, A J; Schols, H A; Gerrits, W J J

    2015-02-01

    Calf milk replacers (MR) commonly contain 40% to 50% lactose. For economic reasons, starch is of interest as a lactose replacer. Compared with lactose, starch digestion is generally low in calves. It is, however, unknown which enzyme limits the rate of starch digestion. The objectives were to determine which enzyme limits starch digestion and to assess the maximum capacity for starch digestion in milk-fed calves. A within-animal titration study was performed, where lactose was exchanged stepwise for one of four starch products (SP). The four corn-based SP differed in size and branching, therefore requiring different ratios of starch-degrading enzymes for their complete hydrolysis to glucose: gelatinised starch (α-amylase and (iso)maltase); maltodextrin ((iso)maltase and α-amylase); maltodextrin with α-1,6-branching (isomaltase, maltase and α-amylase) and maltose (maltase). When exceeding the animal's capacity to enzymatically hydrolyse starch, fermentation occurs, leading to a reduced faecal dry matter (DM) content and pH. Forty calves (13 weeks of age) were assigned to either a lactose control diet or one of four titration strategies (n=8 per treatment), each testing the stepwise exchange of lactose for one SP. Dietary inclusion of each SP was increased weekly by 3% at the expense of lactose and faecal samples were collected from the rectum weekly to determine DM content and pH. The increase in SP inclusion was stopped when faecal DM content dropped below 10.6% (i.e. 75% of the average initial faecal DM content) for 3 consecutive weeks. For control calves, faecal DM content and pH did not change over time. For 87% of the SP-fed calves, faecal DM and pH decreased already at low inclusion levels, and linear regression provided a better fit of the data (faecal DM content or pH v. time) than non-linear regression. For all SP treatments, faecal DM content and pH decreased in time (Pdigestion and that fermentation may contribute substantially to total tract starch

  4. 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

  5. Utilisation of sago starch for wound dressing

    International Nuclear Information System (INIS)

    Kamaruddin Hashim; Khairul Zaman Mohd Dahlan; Kamarudin Bahari

    2000-01-01

    Sago starch is utilized in Malaysia mainly for the purpose of food production. The purpose of the research is to diversify the use of sago starch for medical application particularly in development of hydrogel wound dressing. The sago starch is blending with water-soluble polymer such as polyvinyl pyrrolidone, polyvinyl alcohol and polyethylene oxide and irradiated with electron beam accelerator to form hydrogel. The parameters such gel strength, elasticity, swelling, gel fraction and tackiness have to be consider for this type of application. We also study the effect of adding additive such as carboxymethyl cellulose and polypropylene glycol into the system to enhance the property of sago starch hydrogel. Works on the use of chitosan in the blend have been performed, in order to prevent microbiological growth such as bacteria and fungi on the hydrogel. (author)

  6. Characterization of Digestion Resistance Sweet Potato Starch ...

    African Journals Online (AJOL)

    Purpose: To analyze the physicochemical properties and in vitro digestibility of sweet potato starchphosphodiester prepared using sodium trimetaphosphate. Methods: The physicochemical properties of sweet potato starch phosphodiester were analyzed by using infrared spectrometry (IR), differential scanning calorimetry ...

  7. 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)

  8. 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.

  9. Radiation sterilization of potato starch and Sedonik

    International Nuclear Information System (INIS)

    Tashmetov, M.Yu.; Ismatov, N.B.; Saidov, R.P. et al.

    2016-01-01

    The raw material of pharmaceutical preparations potato starch and sedative means of Sedonik are sterilized at the electron's accelerator Electronics U-003. It is established that at 20.3 kGy absorbed dose and electron's energy 3 - 5 MeV the results of microbiological analysis showed sterility of potato starch and Sedonik and correspondence of their physical-optical properties to the requirements of normative documents. (authors)

  10. Resistant starch: an indigestible fraction of foods

    Directory of Open Access Journals (Sweden)

    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.

  11. Biodegradable starch-based polymeric materials

    Science.gov (United States)

    Suvorova, Anna I.; Tyukova, Irina S.; Trufanova, Elena I.

    2000-05-01

    The effects of low-molecular-weight additives, temperature and mechanical action on the structure and properties of starch are discussed. Special attention is given to mixtures of starch with synthetic polymers, e.g., co-polymers of ethylene with vinyl acetate, vinyl alcohol, acrylic acid, cellulose derivatives and other natural polymers. These mixtures can be used in the development of novel environmentally safe materials (films, coatings, packaging materials) and various articles for short-term use. The bibliography includes 105 references.

  12. 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....

  13. Rheological properties of wheat starch influenced by amylose-lysophosphatidylcholine complexation at different gelation phases

    NARCIS (Netherlands)

    Ahmadiabhari, Salomeh; Woortman, Albert; Hamer, Rob; Loos, Katja

    2015-01-01

    Amylose is able to form helical inclusion complexes with lysophosphatidylcholine (LPC). This complexation influences the functional and rheological properties of wheat starch; however it is well known that the formation of these complexes lead the starchy systems to a slower enzymatic hydrolysis.

  14. Rheological properties of wheat starch influenced by amylose-lysophosphatidylcholine complexation at different gelation phases

    NARCIS (Netherlands)

    Ahmadi-Abhari, S.; Woortman, A.J.J.; Hamer, R.J.; Loos, K.

    2015-01-01

    Amylose is able to form helical inclusion complexes with lysophosphatidylcholine (LPC). This complexation influences the functional and rheological properties of wheat starch; however it is well known that the formation of these complexes lead the starchy systems to a slower enzymatic hydrolysis.

  15. Engineering Potato Starch with a Higher Phosphate Content.

    Directory of Open Access Journals (Sweden)

    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.

  16. Use of MMT and MMT organoclay in production of starch nanocomposites

    International Nuclear Information System (INIS)

    Schlemmer, D.; Sales, M.J.A.; Macedo, J.L. de; Angelica, R.S.

    2010-01-01

    Starch can be used to replace petrochemical plastics for short shelf life. However, starch films have poor mechanical strength and sensitivity to moisture. This can be improved through the incorporation of nanoclays, such as montmorillonite, forming nanocomposites. Nanocomposites were prepared with 1, 3, 5 and 10% of montmorillonite, using pequi oil as plasticizer. The clay was also modified with a quaternary ammonium salt. The clays were characterized by XRF, XRD, IR and TG. Results confirmed the organophilization. The nanocomposites diffractograms showed that the addition of small amounts of clay produces delaminated nanocomposites. Already the addition of larger amount of clay does not form nanocomposites, or leads to the formation of intercalated nanocomposites. (author)

  17. Final Report on Regulation of Guaiacyl and Syringyl Monolignol Biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Vincent L. Chiang

    2006-03-09

    The focus of this research is to understand syringyl monolignol biosynthesis that leads to the formation of syringyl lignin, a type of lignin that can be easily removed during biomass conversion. We have achieved the three originally proposed goals for this project. (1) SAD and CAD genes (enzyme catalytic and kinetic properties) and their functional relevance to CAld5H/AldOMT pathway, (2) spatiotemporal expression patterns of Cald5H, AldOMT, SAD and CAD genes, and (3) functions of CAld5H, AldOMT, and SAD genes in vivo using transgenic aspen. Furthermore, we also found that microRNA might be involved in the upstream regulatory network of lignin biosynthesis and wood formation. The achievements are as below. (1) Based on biochemical and molecular studies, we discovered a novel syringyl-specific alcohol dehydrogenase (SAD) involved in monolignol biosynthesis in angiosperm trees. Through CAld5H/OMT/SAD mediation, syringyl monolignol biosynthesis branches out from guaiacyl pathway at coniferaldehyde; (2) The function of CAld5H gene in this syringyl monolignol biosynthesis pathway also was confirmed in vivo in transgenic Populus; (3) The proposed major monolignol biosynthesis pathways were further supported by the involving biochemical functions of CCR based on a detailed kinetic study; (4) Gene promoter activity analysis also supported the cell-type specific expression of SAD and CAD genes in xylem tissue, consistent with the cell-specific locations of SAD and CAD proteins and with the proposed pathways; (5) We have developed a novel small interfering RNA (siRNA)-mediated stable gene-silencing system in transgenic plants; (6) Using the siRNA and P. trichocarpa transformation/regeneration systems we are currently producing transgenic P. trichocarpa to investigate the interactive functions of CAD and SAD in regulating guaiacyl and syringyl lignin biosynthesis; (7) We have cloned for the first time from a tree species, P. trichocarpa, small regulatory RNAs termed micro

  18. 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.

  19. 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...

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. Thioridazine affects transcription of genes involved in cell wall biosynthesis in methicillin-resistant Staphylococcus aureus

    DEFF Research Database (Denmark)

    Bonde, Mette; Højland, Dorte Heidi; Kolmos, Hans Jørn

    2011-01-01

    have previously shown that the expression of some resistance genes is abolished after treatment with thioridazine and oxacillin. To further understand the mechanism underlying the reversal of resistance, we tested the expression of genes involved in antibiotic resistance and cell wall biosynthesis...... in response to thioridazine in combination with oxacillin. We observed that the oxacillin-induced expression of genes belonging to the VraSR regulon is reduced by the addition of thioridazine. The exclusion of such key factors involved in cell wall biosynthesis will most likely lead to a weakened cell wall...... reversal of resistance by thioridazine relies on decreased expression of specific genes involved in cell wall biosynthesis....

  5. Effect of dispersion parameters on the consolidation of starch-loaded hydroxyapatite slurry

    Directory of Open Access Journals (Sweden)

    Yasser M.Z. Ahmed

    2014-09-01

    Full Text Available The influence of some parameters controlling the hydroxyapatite (HA suspension rheology in terms of heat treatment of the HA powder prior to suspension preparation, suspension solid loading and the amount of corn starch addition was thoroughly investigated. The heat treatment of powder at 1100 °C prior to suspension preparation was found to be extremely efficient in preparing suspensions with high solid loading of 59 vol.%. In contrast, the highest solid loading that could be developed from the non-heat treated powder was 14 vol.%. This phenomenon is consequence of the changes in the physical and chemical properties of the powder after the heat treatment step. The amount of native corn starch addition has ranged from 10 to 40 vol.%. The addition of corn starch leads to the high retardation in the suspension viscosity, particularly at low shear rate. On the contrary, at higher shear rate the situation is completely different. The properties of the consolidated green sample (produced from suspensions containing various corn starch amounts in terms of relative density and compressive strength were studied. The results indicated that even though there were no considerable changes in the relative density, the compressive strength was sharply increased with increasing starch amount content until it reached a maximum at 30 vol.% and then decreased thereafter.

  6. 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.

  7. 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.

  8. Retrogradation of Maize Starch after High Hydrostatic Pressure Gelation: Effect of Amylose Content and Depressurization Rate

    KAUST Repository

    Yang, Zhi; Swedlund, Peter; Gu, Qinfen; Hemar, Yacine; Chaieb, Saharoui

    2016-01-01

    High hydrostatic pressure (HHP) has been employed to gelatinize or physically modify starch dispersions. In this study, waxy maize starch, normal maize starch, and two high amylose content starch were processed by a HHP of the order of 600 MPa

  9. High surface area starch products as filler-binder in direct compression tablets

    NARCIS (Netherlands)

    te Wierik, G.HP; Ramaker, J.S; Eissens, A.C; Bergsma, J; Arends-Scholte, A.W.; Lerk, C.F

    Amylodextrin and modified starch products were prepared from amylose-free starches and from (amylose containing) potato starch by enzymatic degradation, followed by precipitation and filtration. The intermediate retrograded starch products were dehydrated by drying at room temperature or washing

  10. Post-harvest conservation of organic strawberries coated with cassava starch and chitosan

    Directory of Open Access Journals (Sweden)

    Raquel P Campos

    2011-10-01

    Full Text Available The strawberry is as non-climacteric fruit, but has a high post-harvest respiration rate, which leads to a rapid deterioration at room temperature. This study aimed to evaluate the application of biodegradable coating on postharvest conservation of organic strawberries, cv. Camarosa, packed in plastic hinged boxes and stored at 10ºC. The treatments consisted of: a control; b 2% cassava starch; c 1% chitosan; and d 2% cassava starch + 1% chitosan. Physical and chemical characteristics of fruits were evaluated at 3, 6 and 9 days of storage, and microbiological and sensory analyses were carried out at the end of the storage period. The treatments influenced positively the post-harvest quality of organic strawberries. The coating cassava starch + chitosan provided the best results, with less than 6% of loss in fruit mass, lower counts of yeast and psychrophilic microorganisms and the best appearance according to the sensory analysis.

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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....

  17. 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.

  18. 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...

  19. 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

  20. Isolation and characterisation of starch biosynthesis genes from cassava (Manihot esculenta Crantz)

    NARCIS (Netherlands)

    Munyikwa, T.R.I.

    1997-01-01


    Cassava (Manihot esculenta Crantz) is a tropical crop grown for its starchy thickened roots, mainly by peasant farmers, in the tropics, for whom it is a staple food. There is an increasing demand for the use of cassava in processed food and feed products, and in the

  1. The enzymology of polyether biosynthesis.

    Science.gov (United States)

    Liu, Tiangang; Cane, David E; Deng, Zixin

    2009-01-01

    Polyether ionophore antibiotics are a special class of polyketides widely used in veterinary medicine, and as food additives in animal husbandry. In this article, we review current knowledge about the mechanism of polyether biosynthesis, and the genetic and biochemical strategies used for its study. Several clear differences distinguish it from traditional type I modular polyketide biosynthesis: polyether backbones are assembled by modular polyketide synthases but are modified by two key enzymes, epoxidase and epoxide hydrolase, to generate the product. All double bonds involved in the oxidative cyclization in the polyketide backbone are of E geometry. Chain release in the polyether biosynthetic pathway requires a special type II thioesterase which specifically hydrolyzes the polyether thioester. All these discoveries should be very helpful for a deep understanding of the biosynthetic mechanism of this class of important natural compounds, and for the targeted engineering of polyether derivatives.

  2. 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.

  3. 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®

  4. 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.

  5. DGAT enzymes and triacylglycerol biosynthesis

    OpenAIRE

    Yen, Chi-Liang Eric; Stone, Scot J.; Koliwad, Suneil; Harris, Charles; Farese, Robert V.

    2008-01-01

    Triacylglycerols (triglycerides) (TGs) are the major storage molecules of metabolic energy and FAs in most living organisms. Excessive accumulation of TGs, however, is associated with human diseases, such as obesity, diabetes mellitus, and steatohepatitis. The final and the only committed step in the biosynthesis of TGs is catalyzed by acyl-CoA:diacylglycerol acyltransferase (DGAT) enzymes. The genes encoding two DGAT enzymes, DGAT1 and DGAT2, were identified in the past decade, ...

  6. 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...

  7. 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...

  8. 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.

  9. Increased sesquiterpenoid biosynthesis and an apparent decrease in sterol biosynthesis in elicitor-treated tobacco cell suspension cultures

    International Nuclear Information System (INIS)

    Voegeli, U.; Bhatt, P.N.; Chappell, J.

    1987-01-01

    Addition of fungel elicitor prepared from Phytophthora parasitica to tobacco cell suspension cultures leads to an increased production of the phytoalexin capsidiol. Capsidiol is a sesquiterpenoid which is most likely synthesized from farnesylpyrophosphat (FPP) by a bicyclic cyclase reaction. Because FPP is also a substrate for squalene synthetase and therefore a precursor of sterol biosynthesis, the question arises whether or not the accumulation of capsidiol in elicitor-treated cells occurs at the expense of sterol biosynthesis. ( 14 C]-acetate was given to elicitor-treated and control (no treatment) cell cultures and incorporation into sterols and capsidiol determined. No labeled capsidiol was detected in control cells. In elicitor-treated cells about 12-15% of the radioactivity taken up by the cells was incorporated into capsidiol. In contrast, control cells incorporated 4 times more radioactivity into sterols than elicitor-treated cells. Similar results were obtained using ( 3 H)-mevalonate as a precursor of capsidiol and sterol biosynthesis. Likely explanations for the apparently decline in sterol biosynthesis in elicitor-treated cells include: (1) inhibition of squalene synthetase; (2) induction of capsidiol synthesizing enzymes; and (3) metabolic channeling of FPP into capsidiol versus sterols. These possibilities will be discussed further together with other results

  10. 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.

  11. 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.

  12. 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...

  13. Effects of processing conditions on hydrolysis of cassava starch ...

    African Journals Online (AJOL)

    amyloglucosidase using 30% initial cassava starch concentration, which produced 152 g/l reducing sugar concentration and DE of 50.9. The total effective operating time was 60 h. Keywords:Cassava starch, hydrolysis, enzyme, dextrose equivalent.

  14. Comparative studies of starch susceptibilities to α-amylase ...

    African Journals Online (AJOL)

    ayoade

    of the four starch samples varied; amylose content of starch from maize varieties was higher than ... plants as an energy store. ... staple foods as potatoes, wheat, maize (corn), rice and ... of its various chemical and physical properties, can be.

  15. High throughput screening of starch structures using carbohydrate microarrays

    DEFF Research Database (Denmark)

    Tanackovic, Vanja; Rydahl, Maja Gro; Pedersen, Henriette Lodberg

    2016-01-01

    In this study we introduce the starch-recognising carbohydrate binding module family 20 (CBM20) from Aspergillus niger for screening biological variations in starch molecular structure using high throughput carbohydrate microarray technology. Defined linear, branched and phosphorylated...

  16. Evaluation of Starch Biodegradable Plastics Derived from Cassava ...

    African Journals Online (AJOL)

    BSN

    bioplastics produced from cassava does not depend on the level of amylose and amylopectin in the starch per se ... cassava starch is a pure, natural biopolymer that is suitable for ... enzymatic action of microorganisms when disposed, is thus ...

  17. composition and physicochemical properties of starch from christ

    African Journals Online (AJOL)

    Thompson O. Izuagie

    and physicochemical properties of the extracted starch were determined using standard methods. ... water, decorticated to remove skin, dried and ground .... Starches of oval shape have been reported by Hoover et al. ... Figure 2 shows values.

  18. Preparation of Edible Corn Starch Phosphate with Highly Reactive ...

    African Journals Online (AJOL)

    1Food & Bioengineering Department, Henan University of Science and Technology, Luoyang, Henan 471003 ... Purpose: To prepare edible corn starch phosphate under optimized experimental conditions. ... In food industry, starch phosphate.

  19. Modeling and experimental studies on intermittent starch feeding and citrate addition in simultaneous saccharification and fermentation of starch to flavor compounds.

    Science.gov (United States)

    Chavan, Abhijit R; Raghunathan, Anuradha; Venkatesh, K V

    2009-04-01

    Simultaneous saccharification and fermentation (SSF) is a combined process of saccharification of a renewable bioresource and fermentation process to produce products, such as lactic acid and ethanol. Recently, SSF has been extensively used to convert various sources of cellulose and starch into fermentative products. Here, we present a study on production of buttery flavors, namely diacetyl and acetoin, by growing Lactobacillus rhamnosus on a starch medium containing the enzyme glucoamylase. We further develop a structured kinetics for the SSF process, which includes enzyme and growth kinetics. The model was used to simulate the effect of pH and temperature on the SSF process so as to obtain optimum operating conditions. The model was experimentally verified by conducting SSF using an initial starch concentration of 100 g/L. The study demonstrated that the developed kinetic was able to suggest strategies for improved productivities. The developed model was able to accurately predict the enhanced productivity of flavors in a three stage process with intermittent addition of starch. Experimental and simulations demonstrated that citrate addition can also lead to enhanced productivity of flavors. The developed optimal model for SSF was able to capture the dynamics of SSF in batch mode as well as in a three stage process. The structured kinetics was also able to quantify the effect of multiple substrates present in the medium. The study demonstrated that structured kinetic models can be used in the future for design and optimization of SSF as a batch or a fed-batch process.

  20. 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.

  1. 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.

  2. 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

  3. Retention of Cationic Starch onto Cellulose Fibres

    Science.gov (United States)

    Missaoui, Mohamed; Mauret, Evelyne; Belgacem, Mohamed Naceur

    2008-08-01

    Three methods of cationic starch titration were used to quantify its retention on cellulose fibres, namely: (i) the complexation of CS with iodine and measurement of the absorbency of the ensuing blue solution by UV-vis spectroscopy; (ii) hydrolysis of the starch macromolecules followed by the conversion of the resulting sugars to furan-based molecules and quantifying the ensuing mixture by measuring their absorbance at a Ι of 490 nm, using the same technique as previous one and; finally (iii) hydrolysis of starch macromolecules by trifluoro-acetic acid and quantification of the sugars in the resulting hydrolysates by high performance liquid chromatography. The three methods were found to give similar results within the range of CS addition from 0 to 50 mg per g of cellulose fibres.

  4. Examination of injection moulded thermoplastic maize starch

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available This paper focuses on the effect of the different injection moulding parameters and storing methods on injection moulded thermoplastic maize starch (TPS. The glycerol and water plasticized starch was processed in a twin screw extruder and then with an injection moulding machine to produce TPS dumbbell specimens. Different injection moulding set-ups and storing conditions were used to analyse the effects on the properties of thermoplastic starch. Investigated parameters were injection moulding pressure, holding pressure, and for the storage: storage at 50% relative humidity, and under ambient conditions. After processing the mechanical and shrinkage properties of the manufactured TPS were determined as a function of the ageing time. While conditioning, the characteristics of the TPS changed from a soft material to a rigid material. Although this main behaviour remained, the different injection moulding parameters changed the characteristics of TPS. Scanning electron microscope observations revealed the changes in the material on ageing.

  5. 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.

  6. Biosynthesis of archaeal membrane ether lipids

    Directory of Open Access Journals (Sweden)

    Samta eJain

    2014-11-01

    Full Text Available A vital function of the cell membrane in all living organism is to maintain the membrane permeability barrier and fluidity. The composition of the phospholipid bilayer is distinct in archaea when compared to bacteria and eukarya. In archaea, isoprenoid hydrocarbon side chains are linked via an ether bond to the sn-glycerol-1-phosphate backbone. In bacteria and eukarya on the other hand, fatty acid side chains are linked via an ester bond to the sn-glycerol-3-phosphate backbone. The polar head groups are globally shared in the three domains of life. The unique membrane lipids of archaea have been implicated not only in the survival and adaptation of the organisms to extreme environments but also to form the basis of the membrane composition of the last universal common ancestor (LUCA. In nature, a diverse range of archaeal lipids is found, the most common are the diether (or archaeol and the tetraether (or caldarchaeol lipids that form a monolayer. Variations in chain length, cyclization and other modifications lead to diversification of these lipids. The biosynthesis of these lipids is not yet well understood however progress in the last decade has led to a comprehensive understanding of the biosynthesis of archaeol. This review describes the current knowledge of the biosynthetic pathway of archaeal ether lipids; insights on the stability and robustness of archaeal lipid membranes; and evolutionary aspects of the lipid divide and the last universal common ancestor LUCA. It examines recent advances made in the field of pathway reconstruction in bacteria.

  7. Starch deposits in Themeda triandra Forsk | WRE | African Journal of ...

    African Journals Online (AJOL)

    Themeda triandra tillers were examined microscopically at one to two-weekly intervals to determine where starch was deposited. Large numbers of starch grains were always present but the position of these deposits varied according to growth activity and flowering time of the plant. Starch deposits in the roots were usually ...

  8. 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 ...

  9. 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, ...

  10. Coordination of cassava starch to metal ions and thermolysis of ...

    African Journals Online (AJOL)

    Cassava starch formed Werner-type complexes with ions of metals from the transition groups. This was proven by conductivity and electron paramagnetic resonance measurements. The coordination of starch to central metal ions influenced the thermal decomposition of starch. As a rule complexes started to decompose at ...

  11. Evaluation and Optimization of Godare Starch as a Binder and ...

    African Journals Online (AJOL)

    The binding and disintegrating properties of Godare (Colcosia esculenta) starch in paracetamol tablet formulations were evaluated in comparison with potato starch. Tablet crushing strengths (Hs), friabilities Frs), disintegration times (DTs) and porosities were determined. The results showed that Godare starch has a better ...

  12. 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.

  13. 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

  14. 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...

  15. 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:.

  16. 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

    Starch is stored in amyloplasts of various plants like cereals and legumes and seeds of these plants are used as feedstuffs for farm animals. Starch is the major energy

  17. 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

  18. Evaluation of the effect of ginger modified cassava starch as ...

    African Journals Online (AJOL)

    Raw cassava starch has been used as thickener and binder in the formulation of water based paint, but with a problem of loss of viscosity in a very short period. This study evaluates the modification of cassava starch using active component of ginger extract and its use as a water- based paint thickener. 150 g of starch in ...

  19. Control of starch content in potato

    International Nuclear Information System (INIS)

    Korshunov, A.V.; Filippova, G.I.; Gaitova, N.A.; Kutovenko, L.N.

    2010-01-01

    The physiological and biochemical changes and connections defining the starch accumulation in potato tubers are showed. Using the radioisotope C14O2 are analysed data on carbohydrates accumulation in leaves, speed of their movement in tubers, synthetic and decomposing enzyme activities in plant organs, the content of starch in tubers depending on the combination of fertilizers. The necessity for dose phosphorus application level not lower than nitrogen is reasoned. Recommendations on the optimal combination of macrofertilizers, ensuring compromise between yield and tuber starchiness for sod-podzoil sandy-loam and loamy, grey forest, peat, chernozem soils in dry-farming and irrigation are given [ru

  20. Digestion of isolated legume cells in a stomach-duodenum model: three mechanisms limit starch and protein hydrolysis.

    Science.gov (United States)

    Bhattarai, Rewati R; Dhital, Sushil; Wu, Peng; Chen, Xiao Dong; Gidley, Michael J

    2017-07-19

    Retention of intact plant cells to the end of the small intestine leads to transport of entrapped macronutrients such as starch and protein for colonic microbial fermentation, and is a promising mechanism to increase the content of resistant starch in diets. However, the effect of gastro-intestinal bio-mechanical processing on the intactness of plant cells and the subsequent resistance to enzymatic digestion of intracellular starch and protein are not well understood. In this study, intact cells isolated from legume cotyledons are digested in a laboratory model which mimics the mechanical and biochemical conditions of the rat stomach and duodenum. The resulting digesta are characterised in terms of cell (wall) integrity as well as intracellular starch and protein hydrolysis. The cells remained essentially intact in the model with negligible (ca. 2-3%) starch or protein digestion; however when the cells were mechanically broken and digested in the model, the hydrolysis was increased to 45-50% suggesting that intact cellular structures could survive the mixing regimes in the model stomach and duodenum sufficiently to prevent digestive enzyme access. Apart from intact cell walls providing effective barrier properties, they also limit digestibility by restricting starch gelatinisation during cooking, and significant non-specific binding of α-amylase is observed to both intact and broken cell wall components, providing a third mechanism hindering starch hydrolysis. The study suggests that the preservation of intactness of plant cells, such as from legumes, could be a viable approach to achieve the targeted delivery of resistant starch to the colon.

  1. High amylose resistant starch diet ameliorates oxidative stress, inflammation, and progression of chronic kidney disease.

    Directory of Open Access Journals (Sweden)

    Nosratola D Vaziri

    Full Text Available Inflammation is a major mediator of CKD progression and is partly driven by altered gut microbiome and intestinal barrier disruption, events which are caused by: urea influx in the intestine resulting in dominance of urease-possessing bacteria; disruption of epithelial barrier by urea-derived ammonia leading to endotoxemia and bacterial translocation; and restriction of potassium-rich fruits and vegetables which are common sources of fermentable fiber. Restriction of these foods leads to depletion of bacteria that convert indigestible carbohydrates to short chain fatty acids which are important nutrients for colonocytes and regulatory T lymphocytes. We hypothesized that a high resistant starch diet attenuates CKD progression. Male Sprague Dawley rats were fed a chow containing 0.7% adenine for 2 weeks to induce CKD. Rats were then fed diets supplemented with amylopectin (low-fiber control or high fermentable fiber (amylose maize resistant starch, HAM-RS2 for 3 weeks. CKD rats consuming low fiber diet exhibited reduced creatinine clearance, interstitial fibrosis, inflammation, tubular damage, activation of NFkB, upregulation of pro-inflammatory, pro-oxidant, and pro-fibrotic molecules; impaired Nrf2 activity, down-regulation of antioxidant enzymes, and disruption of colonic epithelial tight junction. The high resistant starch diet significantly attenuated these abnormalities. Thus high resistant starch diet retards CKD progression and attenuates oxidative stress and inflammation in rats. Future studies are needed to explore the impact of HAM-RS2 in CKD patients.

  2. Modification of porous starch for the adsorption of heavy metal ions from aqueous solution.

    Science.gov (United States)

    Ma, Xiaofei; Liu, Xueyuan; Anderson, Debbie P; Chang, Peter R

    2015-08-15

    Porous starch xanthate (PSX) and porous starch citrate (PSC) were prepared in anticipation of the attached xanthate and carboxylate groups respectively forming chelation and electrostatic interactions with heavy metal ions in the subsequent adsorption process. The lead(II) ion was selected as the model metal and its adsorption by PSX and PSC was characterized. The adsorption capacity was highly dependent on the carbon disulfide/starch and citric acid/starch mole ratios used during preparation. The adsorption behaviors of lead(II) ion on PSXs and PSCs fit both the pseudo-second-order kinetic model and the Langmuir isotherm model. The maximum adsorption capacity from the Langmuir isotherm equation reached 109.1 and 57.6 mg/g for PSX and PSC when preparation conditions were optimized, and the adsorption times were just 20 and 60 min, respectively. PSX and PSC may be used as effective adsorbents for removal of heavy metals from contaminated liquid. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  3. 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

  4. Effects of cross-linking modification with phosphoryl chloride (POCl3 on pysiochemical properties of barely starch

    Directory of Open Access Journals (Sweden)

    Zahra Malekpour

    2016-05-01

    Full Text Available Chemical methods are one of the comon method in starch modification. This study aimed at investigating of cross-link affection of phosphoryl chloride with two different levels 0.5 and 1g.kg-1 in order to enhance funciotnal proeprties and physiochemical changes on extracted starch from barely variety Bahman which cultivates in Chahr-Mahal Bakhtiari Province of Iran. Obtained results indicated that cross-linking leads to reduce sweeling power of strach granuls compred to natural starch and the amount of reduciton increase via the substitituin level. Powerfull cross-linkingnetween starch chains casue more resistance of granules to seweeling which is increased by means of cross-linking dgree. Additioally,  investigationresults from synersis revealed that releasing water percentage in cross-linked starches increase in comparison to natural starches and this amount depends onthe amount of cross-link surface with a significantly difference in (α <0.05. Gelatinization temperature in both levels negligibly increased by modification where in low level of cross-linking was more. Furthermoe evaluating gelation temperatures of both natural and cross-linked modified starches showed that addition of phosphate groups in starch and creating extra coovalent bonds make granues more compressed reulting in slight increase of To, Tp, Tcin barely starch. Icreasing of temperature observed more in less concentration of cross-links. Evaluation of viscosity changes also revealed that this modification depending on increasing the amount of Phosphoryl Chloride led to increasing peak temperature, diminish peak and setback viscosity. Result also exhibited that in morphological level, cross-link causes to incidence changes in particles' diameter size. The comparison of diameter average and frequency between natural starch and cross-links starch exhibited that in cross-linkd treatment with 0.5% phosphoryl chloride, increase in frequency of granules with diameter of 6 - 10µm

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

    CSIR Research Space (South Africa)

    Wokadala, OC

    2014-06-01

    Full Text Available In this study, waxy and high amylose starches were modified through butyl-etherification to facilitatecompatibility with polylactide (PLA). Fourier transform infrared spectroscopy, proton nuclear magneticresonance spectroscopy and wettability tests...

  6. Mechanical Properties of Isotactic Polypropylene Modified with Thermoplastic Potato Starch

    Science.gov (United States)

    Knitter, M.; Dobrzyńska-Mizera, M.

    2015-05-01

    In this paper selected mechanical properties of isotactic polypropylene (iPP) modified with potato starch have been presented. Thermoplastic starch (TPS) used as a modifier in the study was produced from potato starch modified with glycerol. Isotactic polypropylene/thermoplastic potato starch composites (iPP/TPS) that contained 10, 30, 50 wt.% of modified starch were examined using dynamic mechanical-thermal analysis, static tensile, Brinell hardness, and Charpy impact test. The studies indicated a distinct influence of a filler content on the mechanical properties of composites in comparison with non-modified polypropylene.

  7. Oleic acid biosynthesis in cyanobacteria

    International Nuclear Information System (INIS)

    VanDusen, W.J.; Jaworski, J.G.

    1986-01-01

    The biosynthesis of fatty acids in cyanobacteria is very similar to the well characterized system found in green plants. However, the initial desaturation of stearic acid in cyanobacteria appears to represent a significant departure from plant systems in which stearoyl-ACP is the exclusive substrate for desaturation. In Anabaena variabilis, the substrate appears to be monoglucosyldiacylglycerol, a lipid not found in plants. The authors examined five different cyanobacteria to determine if the pathway in A. variabilis was generally present in other cyanobacteria. The cyanobacteria studied were A. variabilis, Chlorogloeopsis sp., Schizothrix calcicola, Anacystis marina, and Anacystis nidulans. Each were grown in liquid culture, harvested, and examined for stearoyl-ACP desaturase activity or incubated with 14 CO 2 . None of the cyanobacteria contained any stearoyl-ACP desaturase activity in whole homogenates or 105,000g supernatants. All were capable of incorporating 14 CO 2 into monoglucosyldiacylglycerol and results from incubations of 20 min, 1 hr, 1 hr + 10 hr chase were consistent with monoglucosyldiacylglycerol serving as precursor for monogalctosyldiacylglycerol. Thus, initial evidence is consistent with oleic acid biosynthesis occurring by desaturation of stearoyl-monoglucosyldiacylglycerol in all cyanobacteria

  8. 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...

  9. Wheat B-starch based polymeric materials

    Czech Academy of Sciences Publication Activity Database

    Kotek, Jiří; Kruliš, Zdeněk; Šárka, E.

    2011-01-01

    Roč. 105, č. 9 (2011), s. 731 ISSN 0009-2770. [International Conference on Polysaccharides-Glycoscience /7./. 02.11.2011-04.11.2011, Prague] R&D Projects: GA ČR GA525/09/0607 Institutional research plan: CEZ:AV0Z40500505 Keywords : biodegradable plastic * polycaprolactone * B- starch Subject RIV: JI - Composite Materials

  10. Starch: chemistry, microstructure, processing and enzymatic degradation

    Science.gov (United States)

    Starch is recognized as one of the most abundant and important commodities containing value added attributes for a vast number of industrial applications. Its chemistry, structure, property and susceptibility to various chemical, physical and enzymatic modifications offer a high technological value ...

  11. Starch facilitates enzymatic wheat gluten hydrolysis

    NARCIS (Netherlands)

    Hardt, N.A.; Boom, R.M.; Goot, van der A.J.

    2015-01-01

    Wheat gluten can be hydrolyzed by either using (vital) wheat gluten or directly from wheat flour. This study investigates the influence of the presence of starch, the main component of wheat, on enzymatic wheat gluten hydrolysis. Wheat gluten present in wheat flour (WFG) and vital wheat gluten (VWG)

  12. 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.

  13. 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...

  14. Biodegradability and mechanical properties of starch films from Andean crops.

    Science.gov (United States)

    Torres, F G; Troncoso, O P; Torres, C; Díaz, D A; Amaya, E

    2011-05-01

    Different Andean crops were used to obtain starches not previously reported in literature as raw material for the production of biodegradable polymers. The twelve starches obtained were used to prepare biodegradable films by casting. Water and glycerol were used as plasticizers. The mechanical properties of the starch based films were assessed by means of tensile tests. Compost tests and FTIR tests were carried out to assess biodegradability of films. The results show that the mechanical properties (UTS, Young's modulus and elongation at break) of starch based films strongly depend on the starch source used for their production. We found that all the starch films prepared biodegrade following a three stage process and that the weight loss rate of all the starch based films tested was higher than the weight loss rate of the cellulose film used as control. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. 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

  16. LEADING WITH LEADING INDICATORS

    International Nuclear Information System (INIS)

    PREVETTE, S.S.

    2005-01-01

    This paper documents Fluor Hanford's use of Leading Indicators, management leadership, and statistical methodology in order to improve safe performance of work. By applying these methods, Fluor Hanford achieved a significant reduction in injury rates in 2003 and 2004, and the improvement continues today. The integration of data, leadership, and teamwork pays off with improved safety performance and credibility with the customer. The use of Statistical Process Control, Pareto Charts, and Systems Thinking and their effect on management decisions and employee involvement are discussed. Included are practical examples of choosing leading indicators. A statistically based color coded dashboard presentation system methodology is provided. These tools, management theories and methods, coupled with involved leadership and employee efforts, directly led to significant improvements in worker safety and health, and environmental protection and restoration at one of the nation's largest nuclear cleanup sites

  17. 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.

  18. Determination of surface energies of hot-melt extruded sugar-starch pellets.

    Science.gov (United States)

    Yeung, Chi-Wah; Rein, Hubert

    2018-02-01

    Hot-melt extruded sugar-starch pellets are an alternative for commercial sugar spheres, but their coating properties remain to be studied. Both the European Pharmcopoeia 8.6 and the United States Pharmacopoeia 40 specify the composition of sugar-starch pellets without giving requirements for the manufacturing process. Due to various fabrication techniques, the physicochemical properties of pellets may differ. Therefore, the adhesion energies of three coating dispersions (sustained, enteric and immediate release) on different types of pellets were investigated. In this context, the surface energies of various kinds of corn starch (normal, waxy, high-amylose) and sucrose pellets were analyzed using the sessile drop method, whereas the surface tensions of the coating dispersions were examined using the pendant drop method. The adhesion forces were calculated from the results of these studies. Furthermore, sugar spheres were characterized in terms of particle size distribution, porosity and specific surface area. An increase of the pellets' sucrose content leads to a more porous surface structure, which gives them an enhanced wetting behavior with coating dispersions. The adhesion energies of extruded sugar-starch pellets are similar to those of commercial sugar spheres, which comply with pharmacopeial requirements. Both types of pellets are equally suited for coating.

  19. Peculiarities of Enhancing Resistant Starch in Ruminants Using Chemical Methods: Opportunities and Challenges

    Directory of Open Access Journals (Sweden)

    Qendrim Zebeli

    2013-06-01

    Full Text Available High-producing ruminants are fed high amounts of cereal grains, at the expense of dietary fiber, to meet their high energy demands. Grains consist mainly of starch, which is easily degraded in the rumen by microbial glycosidases, providing energy for rapid growth of rumen microbes and short-chain fatty acids (SCFA as the main energy source for the host. Yet, low dietary fiber contents and the rapid accumulation of SCFA lead to rumen disorders in cattle. The chemical processing of grains has become increasingly important to confer their starch resistances against rumen microbial glycosidases, hence generating ruminally resistant starch (RRS. In ruminants, unlike monogastric species, the strategy of enhancing resistant starch is useful, not only in lowering the amount of carbohydrate substrates available for digestion in the upper gut sections, but also in enhancing the net hepatic glucose supply, which can be utilized by the host more efficiently than the hepatic gluconeogenesis of SCFA. The use of chemical methods to enhance the RRS of grains and the feeding of RRS face challenges in the practice; therefore, the present article attempts to summarize the most important achievements in the chemical processing methods used to generate RRS, and review advantages and challenges of feeding RRS to ruminants

  20. 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.

  1. DGAT enzymes and triacylglycerol biosynthesis

    Science.gov (United States)

    Yen, Chi-Liang Eric; Stone, Scot J.; Koliwad, Suneil; Harris, Charles; Farese, Robert V.

    2008-01-01

    Triacylglycerols (triglycerides) (TGs) are the major storage molecules of metabolic energy and FAs in most living organisms. Excessive accumulation of TGs, however, is associated with human diseases, such as obesity, diabetes mellitus, and steatohepatitis. The final and the only committed step in the biosynthesis of TGs is catalyzed by acyl-CoA:diacylglycerol acyltransferase (DGAT) enzymes. The genes encoding two DGAT enzymes, DGAT1 and DGAT2, were identified in the past decade, and the use of molecular tools, including mice deficient in either enzyme, has shed light on their functions. Although DGAT enzymes are involved in TG synthesis, they have distinct protein sequences and differ in their biochemical, cellular, and physiological functions. Both enzymes may be useful as therapeutic targets for diseases. Here we review the current knowledge of DGAT enzymes, focusing on new advances since the cloning of their genes, including possible roles in human health and diseases. PMID:18757836

  2. 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.

  3. 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

  4. 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.).

  5. Distinct Prominent Roles for Enzymes of Plasmodium berghei Heme Biosynthesis in Sporozoite and Liver Stage Maturation

    Science.gov (United States)

    Matuschewski, Kai; Haussig, Joana M.

    2016-01-01

    Malarial parasites have evolved complex regulation of heme supply and disposal to adjust to heme-rich and -deprived host environments. In addition to its own pathway for heme biosynthesis, Plasmodium likely harbors mechanisms for heme scavenging from host erythrocytes. Elaborate compartmentalization of de novo heme synthesis into three subcellular locations, including the vestigial plastid organelle, indicates critical roles in life cycle progression. In this study, we systematically profile the essentiality of heme biosynthesis by targeted gene deletion of enzymes in early steps of this pathway. We show that disruption of endogenous heme biosynthesis leads to a first detectable defect in oocyst maturation and sporogony in the Anopheles vector, whereas blood stage propagation, colonization of mosquito midguts, or initiation of oocyst development occurs indistinguishably from that of wild-type parasites. Although sporozoites are produced by parasites lacking an intact pathway for heme biosynthesis, they are absent from mosquito salivary glands, indicative of a vital role for heme biosynthesis only in sporozoite maturation. Rescue of the first defect in sporogony permitted analysis of potential roles in liver stages. We show that liver stage parasites benefit from but do not strictly depend upon their own aminolevulinic acid synthase and that they can scavenge aminolevulinic acid from the host environment. Together, our experimental genetics analysis of Plasmodium enzymes for heme biosynthesis exemplifies remarkable shifts between the use of endogenous and host resources during life cycle progression. PMID:27600503

  6. 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.

  7. 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.

  8. 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.

  9. Starch Characteristics Linked to Gluten-Free Products

    Directory of Open Access Journals (Sweden)

    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.

  10. 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.

  11. Bacterial cellulose biosynthesis: diversity of operons, subunits, products and functions

    Science.gov (United States)

    Römling, Ute; Galperin, Michael Y.

    2015-01-01

    Summary Recent studies of bacterial cellulose biosynthesis, including structural characterization of a functional cellulose synthase complex, provided the first mechanistic insight into this fascinating process. In most studied bacteria, just two subunits, BcsA and BcsB, are necessary and sufficient for the formation of the polysaccharide chain in vitro. Other subunits – which differ among various taxa – affect the enzymatic activity and product yield in vivo by modulating expression of biosynthesis apparatus, export of the nascent β-D-glucan polymer to the cell surface, and the organization of cellulose fibers into a higher-order structure. These auxiliary subunits play key roles in determining the quantity and structure of the resulting biofilm, which is particularly important for interactions of bacteria with higher organisms that lead to rhizosphere colonization and modulate virulence of cellulose-producing bacterial pathogens inside and outside of host cells. Here we review the organization of four principal types of cellulose synthase operons found in various bacterial genomes, identify additional bcs genes that encode likely components of the cellulose biosynthesis and secretion machinery, and propose a unified nomenclature for these genes and subunits. We also discuss the role of cellulose as a key component of biofilms formed by a variety of free-living and pathogenic bacteria and, for the latter, in the choice between acute infection and persistence in the host. PMID:26077867

  12. 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

  13. 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

  14. Properties of foam and composite materials made o starch and cellulose fiber

    Science.gov (United States)

    Composite materials were made of starch and cellulose fibers. Pre-gelatinized starch was effective in dispersing pulp fiber in a starch matrix to form a viscous starch/fiber dough. The starch/fiber dough was a useful feedstock for various composite foam and plastic materials. Viscous blends of star...

  15. Transcriptional analysis of apple fruit proanthocyanidin biosynthesis

    Science.gov (United States)

    Henry-Kirk, Rebecca A.

    2012-01-01

    Proanthocyanidins (PAs) are products of the flavonoid pathway, which also leads to the production of anthocyanins and flavonols. Many flavonoids have antioxidant properties and may have beneficial effects for human health. PAs are found in the seeds and fruits of many plants. In apple fruit (Malus × domestica Borkh.), the flavonoid biosynthetic pathway is most active in the skin, with the flavan-3-ols, catechin, and epicatechin acting as the initiating units for the synthesis of PA polymers. This study examined the genes involved in the production of PAs in three apple cultivars: two heritage apple cultivars, Hetlina and Devonshire Quarrenden, and a commercial cultivar, Royal Gala. HPLC analysis shows that tree-ripe fruit from Hetlina and Devonshire Quarrenden had a higher phenolic content than Royal Gala. Epicatechin and catechin biosynthesis is under the control of the biosynthetic enzymes anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR1), respectively. Counter-intuitively, real-time quantitative PCR analysis showed that the expression levels of Royal Gala LAR1 and ANR were significantly higher than those of both Devonshire Quarrenden and Hetlina. This suggests that a compensatory feedback mechanism may be active, whereby low concentrations of PAs may induce higher expression of gene transcripts. Further investigation is required into the regulation of these key enzymes in apple. Abbreviations:ANOVAanalysis of varianceANRanthocyanidin reductaseDADdiode array detectorDAFBdays after full bloomDFRdihydroflavonol reductaseLARleucoanthocyanidin reductaseLC-MSliquid chromatography/mass spectrometryPAproanthocyanidinqPCRreal-time quantitative PCR PMID:22859681

  16. Regulation of neurosteroid biosynthesis by neurotransmitters and neuropeptides

    Directory of Open Access Journals (Sweden)

    Jean-Luc eDo-Rego

    2012-01-01

    Full Text Available The enzymatic pathways leading to the synthesis of bioactive steroids in the brain are now almost completely elucidated in various groups of vertebrates and, during the last decade, the neuronal mechanisms involved in the regulation of neurosteroid production have received increasing attention. This report reviews the current knowledge concerning the effects of neurotransmitters, peptide hormones and neuropeptides on the biosynthesis of neurosteroids. Anatomical studies have been carried out to visualize the neurotransmitter- or neuropeptide-containing fibers contacting steroid-synthesizing neurons as well as the neurotransmitter, peptide hormones or neuropeptide receptors expressed in these neurons. Biochemical experiments have been conducted to investigate the effects of neurotransmitters, peptide hormones or neuropeptides on neurosteroid biosynthesis, and to characterize the type of receptors involved. Thus, it has been found that glutamate, acting through kainate and/or AMPA receptors, rapidly inactivates P450arom, and that melatonin produced by the pineal gland and eye inhibits the biosynthesis of 7-hydroxypregnenolone (7-OH-5P, while prolactin produced by the adenohypophysis enhances the formation of 7-OH-5P. It has also been demonstrated that the biosynthesis of neurosteroids is inhibited by GABA, acting through GABAA receptors, and neuropeptide Y, acting through Y1 receptors. In contrast, it has been shown that the octadecaneuropetide ODN, acting through central-type benzodiazepine receptors, the triakontatetraneuropeptide TTN, acting though peripheral-type benzodiazepine receptors, and vasotocine, acting through V1a-like receptors, stimulate the production of neurosteroids. Since neurosteroids are implicated in the control of various neurophysiological and behavioral processes, these data suggest that some of the neurophysiological effects exerted by neurotransmitters and neuropeptides may be mediated via the regulation

  17. The Spatial Organization of Glucosinolate Biosynthesis

    DEFF Research Database (Denmark)

    Nintemann, Sebastian

    cells is an open question. Likewise, it is not known how glucosinolate biosynthesis is orchestrated at the subcellular level. These open questions were addressed with several approaches in this project, with the aim of shedding light on the spatial organization of glucosinolate biosynthesis from...... between the individual classes of glucosinolates under constitutive and induced conditions and identified the source tissues of these defense compounds. Protein-protein interaction studies were carried out to investigate the subcellular organization of glucosinolate biosynthesis. We identified a family...

  18. 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 .

  19. 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.

  20. 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.

  1. 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.

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

    Science.gov (United States)

    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.

  3. 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).

  4. Biosynthesis of oligosaccharides and fructans in Agave vera cruz : Part III - Biosynthesis of fructans

    Energy Technology Data Exchange (ETDEWEB)

    Satyanarayana, M N [Central Food Technological Research Inst., Mysore (India). Dept. of Biochemistry

    1976-12-01

    Evidence has been obtained for the biosynthesis of 'fructans' in Agave vera cruz. A hydrolase-free enzyme preparation from the stem juice with U-/sup 14/C sucrose as substrate and the native fructan as primer leads to incorporation of /sup 14/C fructose into a polymer like compound. This inference is based on criteria such as the chromatographic mobility of the product and the elution volume from a Sephadex G-25 column. Two optimum pHs 4.9 and 6.1 and optimum temperature 377degC are observed for the reaction. The activity is dependent on primer, enzyme, substrate concentration and duration of incubation. The ratio of substrate to primer appears to be a special factor; higher ratios retard synthesis (S:P 5:1, 1.14%, S:P 100:1, 0.36% incorporation), while lower ones enhance (reaching a maximum of 11.35% at an S:P ratio of 1.75 in hr). Inulin in place of the native fructan is less efficient as primer. Each of the higher homologues of sucrose, tri to hexasaccharides (tested so far), leads to fructan formation with elution volumes from a Sephadex G-25 column close to that of the primer. U-/sup 14/C fructose or glucose in place of U-/sup 14/C sucrose or absence of enzyme leads to no incorporation. Sucrose seems to have a key role both in the initiation and lengthening of the fructan chain.

  5. 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

  6. 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 '

  7. Improvement of rice starch by gamma irradiation

    International Nuclear Information System (INIS)

    Duan Zhiying; Wu Dianxing; Shen Shengquan; Han Juanying; Xia Yingwu

    2003-01-01

    Three types of rice cultivars, Indica, Japonica and hybrid rice, with similar intermediate apparent amylose content (AAC) as well as early Indica rice cultivars with different amounts of AAC were selected for studying the effects of gamma irradiation on starch viscosity, physico-chemical properties and starch granule structure. Four major parameters of RVA profile, peak viscosity (PKV), hot paste viscosity (HPV), cool paste viscosity (CPV), setback viscosity (SBV) and consistence viscosity (CSV) were considerably decreased with increasing dose levels. Gamma irradiation reduced the amylose contents in the cultivars with low AAC, intermediate AAC, and glutinous rice, but had no effects on the high AAC cultivar. No visible changes in alkali spreading value (ASV) were detected after irradiation, but the peak time (PKT) were reduced with the dose level. Gel consistency (GC) were significantly increased in the tested cultivars, especially in the high AAC Indica rice, suggesting that it is promising to use gamma irradiation to improve eating and cooking quality of rice

  8. Analytical Aspects of Total Starch Polarimetric Determination in Some Cereals

    Directory of Open Access Journals (Sweden)

    Rodica Caprita

    2016-10-01

    Full Text Available Starch is the most important digestible polysaccharide present in foods and feeds. The starch concentration in cereals cannot be determined directly, because the starch is contained within a structurally and chemically complex matrix. Fine grinding and boiling in dilute HCl are preparative steps necessary for complete release of the starch granules from the protein matrix. Starch can be determined using simple and inexpensive physical methods, such as density, refractive index or optical rotation assessment. The polarimetric method allows the determination even of small starch contents due to its extremely high specific rotation. For more accurate results, the contribution of free sugars is eliminated by dissolution in 40% (V/V ethanol. The influence of other optically active substances, which might interfere, is removed by filtration/clarification prior to the optical rotation measurement.

  9. 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.

  10. Reduction of acrylamide content in bread crust by starch coating.

    Science.gov (United States)

    Liu, Jie; Liu, Xiaojie; Man, Yong; Liu, Yawei

    2018-01-01

    A technique of starch coating to reduce acrylamide content in bread crust was proposed. Bread was prepared in accordance with a conventional procedure and corn or potato starch coating was brushed on the surface of the fermented dough prior to baking. Corn starch coating caused a decrease in acrylamide of 66.7% and 77.1% for the outer and inner crust, respectively. The decrease caused by the potato starch coating was 68.4% and 77.4%, respectively. Starch coating reduced asparagine content significantly (43.4-82.9%; P coating, which effectively shortened the time span (4-8 min) over which acrylamide could form and accumulate. The present study demonstrates that starch coating could be a simple, effective and practical application for reducing acrylamide levels in bread crust without changing the texture and crust color of bread. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  11. Preparation and Properties of Cassava Starch-based Wood Adhesives

    Directory of Open Access Journals (Sweden)

    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.

  12. 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.

  13. 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.

  14. Development of nanocomposites based on potato starch

    International Nuclear Information System (INIS)

    Brito, Luciana Macedo; Tavares, Maria Ines Bruno

    2013-01-01

    Nanocomposites of potato starch were prepared by the solution intercalation method with the addition of organically modified montmorillonite clay (Viscogel B and unmodified sodic clay (NT25) as well as modified and unmodified silica (R972 and A200, respectively), using water as the solvent. The nanocomposites were characterized by conventional techniques of X-ray diffraction and thermogravimetric analysis. They were also characterized using the non-conventional low-field nuclear magnetic resonance, which is an effective alternative technique for characterizing nanocomposites. This technique allows one to investigate dispersion of nanofillers by the degree of intercalation and/or exfoliation, in addition to determine the distribution of nanoparticles in the polymer matrix and modifications of the molecular mobility of these fillers. The nanostructured materials obtained with the clays presented good dispersion and formation of mixed nanomaterials, with different degrees of intercalation and exfoliation. The mobility of the material decreased upon adding silica in the starch matrix, which applied to both types of silica. From the TGA technique, a slight increase in thermal stability of the nanocomposite was noted in relation to the starch matrix. (author)

  15. Enzymatic transformation of nonfood biomass to starch

    Science.gov (United States)

    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

  16. Transfer action of cyclodextrin glycosyltransferase on starch

    Energy Technology Data Exchange (ETDEWEB)

    Kitahata, S; Okada, S [Osaka City Technical Research Inst. (Japan)

    1975-11-01

    The transglycosylation reaction of the cyclodextrin glycosyltransferase from Bacillus megaterium (No. 5 enzyme) and Bacillus macerans (BMA) were examined. No.5 enzyme was more efficient in transglycosylation reaction than BMA in the every acceptor employed in the present study. The order of the efficient acceptors for No. 5 enzyme was maltose (G2), glucose (G1), maltotriose (G3) and sucrose (GF). On the other hand, that found for BMA was G1, G2, GF and G3. The transglycosylation products to glucose formed by the action of No. 5 enzyme on starch were G2, G3, maltotetraose (G4), maltopentaose (G5), maltohexaose (G6) and maltoheptaose (G7) in the order of their quantities, while, in the case of BMA, they were G2, G3, G5, G7 = G4 and G6. The larger transglycosylation products to sucrose formed by the action of No. 5 enzyme on starch were maltosylfructose. On the other hand, that formed by the action of BMA was maltoheptaosylfructose. It was suggested that cyclodextrin glycosyltransferase could transfer the glucosyl residues to an acceptor directly from starch, as well as through cyclodextrin.

  17. Monoterpene biosynthesis potential of plant subcellular compartments

    NARCIS (Netherlands)

    Dong, L.; Jongedijk, E.J.; Bouwmeester, H.J.; Krol, van der A.R.

    2016-01-01

    Subcellular monoterpene biosynthesis capacity based on local geranyl diphosphate (GDP) availability or locally boosted GDP production was determined for plastids, cytosol and mitochondria. A geraniol synthase (GES) was targeted to plastids, cytosol, or mitochondria. Transient expression in Nicotiana

  18. Method for determining heterologous biosynthesis pathways

    KAUST Repository

    Gao, Xin; Kuwahara, Hiroyuki; Alazmi, Meshari Saud; Cui, Xuefeng

    2017-01-01

    suitable pathways for the endogenous metabolism of a host organism because the efficacy of heterologous biosynthesis is affected by competing endogenous pathways. The present invention is called MRE (Metabolic Route Explorer), and it was conceived

  19. 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.

  20. Effect of Drying Method and Variety on Quality of Cassava Starch ...

    African Journals Online (AJOL)

    Effect of Drying Method and Variety on Quality of Cassava Starch Extracts. ... Cassava starch is one of the main industrial products of cassava processing. ... Also, cassava starch samples dried at lower temperature have better functional and ...

  1. Effects of citric acid esterification on digestibility, structural and physicochemical properties of cassava starch.

    Science.gov (United States)

    Mei, Ji-Qiang; Zhou, Da-Nian; Jin, Zheng-Yu; Xu, Xue-Ming; Chen, Han-Qing

    2015-11-15

    In this study, citric acid was used to react with cassava starch in order to compare the digestibility, structural and physicochemical properties of citrate starch samples. The results indicated that citric acid esterification treatment significantly increased the content of resistant starch (RS) in starch samples. The swelling power and solubility of citrate starch samples were lower than those of native starch. Compared with native starch, a new peak at 1724 cm(-1) was appeared in all citrate starch samples, and crystalline peaks of all starch citrates became much smaller or even disappeared. Differential scanning calorimetry results indicated that the endothermic peak of citrate starches gradually shrank or even disappeared. Moreover, the citrate starch gels exhibited better freeze-thaw stability. These results suggested that citric acid esterification induced structural changes in cassava starch significantly affected its digestibility and it could be a potential method for the preparation of RS with thermal stability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. 40 CFR 427.30 - Applicability; description of the asbestos paper (starch binder) subcategory.

    Science.gov (United States)

    2010-07-01

    ... asbestos paper (starch binder) subcategory. 427.30 Section 427.30 Protection of Environment ENVIRONMENTAL... Asbestos Paper (Starch Binder) Subcategory § 427.30 Applicability; description of the asbestos paper... asbestos paper (starch binder). ...

  3. 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)

  4. 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....

  5. 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.

  6. Size Controlled Synthesis of Starch Nanoparticles by a Microemulsion Method

    Directory of Open Access Journals (Sweden)

    Suk Fun Chin

    2014-01-01

    Full Text Available Controllable particles sizes of starch nanoparticles were synthesized via a precipitation in water-in-oil microemulsion approach. Microemulsion method offers the advantages of ultralow interfacial tension, large interfacial area, and being thermodynamically stable and affords monodispersed nanoparticles. The synthesis parameters such as stirring rates, ratios of oil/cosurfactant, oil phases, cosurfactants, and ratios of water/oil were found to affect the mean particle size of starch nanoparticles. Starch nanoparticles with mean particles sizes of 109 nm were synthesized by direct nanoprecipitation method, whereas by using precipitation in microemulsion approach, starch nanoparticles with smaller mean particles sizes of 83 nm were obtained.

  7. A rice plastidial nucleotide sugar epimerase is involved in galactolipid biosynthesis and improves photosynthetic efficiency.

    Directory of Open Access Journals (Sweden)

    Chunlai Li

    2011-07-01

    Full Text Available Photosynthesis is the final determinator for crop yield. To gain insight into genes controlling photosynthetic capacity, we selected from our large T-DNA mutant population a rice stunted growth mutant with decreased carbon assimilate and yield production named photoassimilate defective1 (phd1. Molecular and biochemical analyses revealed that PHD1 encodes a novel chloroplast-localized UDP-glucose epimerase (UGE, which is conserved in the plant kingdom. The chloroplast localization of PHD1 was confirmed by immunoblots, immunocytochemistry, and UGE activity in isolated chloroplasts, which was approximately 50% lower in the phd1-1 mutant than in the wild type. In addition, the amounts of UDP-glucose and UDP-galactose substrates in chloroplasts were significantly higher and lower, respectively, indicating that PHD1 was responsible for a major part of UGE activity in plastids. The relative amount of monogalactosyldiacylglycerol (MGDG, a major chloroplast membrane galactolipid, was decreased in the mutant, while the digalactosyldiacylglycerol (DGDG amount was not significantly altered, suggesting that PHD1 participates mainly in UDP-galactose supply for MGDG biosynthesis in chloroplasts. The phd1 mutant showed decreased chlorophyll content, photosynthetic activity, and altered chloroplast ultrastructure, suggesting that a correct amount of galactoglycerolipids and the ratio of glycolipids versus phospholipids are necessary for proper chloroplast function. Downregulated expression of starch biosynthesis genes and upregulated expression of sucrose cleavage genes might be a result of reduced photosynthetic activity and account for the decreased starch and sucrose levels seen in phd1 leaves. PHD1 overexpression increased photosynthetic efficiency, biomass, and grain production, suggesting that PHD1 plays an important role in supplying sufficient galactolipids to thylakoid membranes for proper chloroplast biogenesis and photosynthetic activity. These

  8. Composite wheat-plantain starch salted noodles: Preparation, proximal composition and in vitro starch digestibility

    OpenAIRE

    Rendón-Villalobos, Rodolfo; Osorio-Díaz, Perla; Agama-Acevedo, Edith; Tovar, Juscelino; Bello-Pérez, Luis A

    2008-01-01

    Salted noodles were prepared with different contents of wheat grits and plantain starch (PS). The blends were hydrated with 2% NaCl (w/v), homogenized, and the resulting doughs were sheeted through a pasta machine, cut into strips ~30cm in length, cooked, and their composition and in vitro starch digestibility was assessed. Moisture (6.43-7.60%) and ash contents (2.08-3.12%) increased by the addition of PS. Fat level decreased from 0.41 to 0.31% as the substitution of wheat grits increased. R...

  9. Novel polymer blends with thermoplastic starch

    Science.gov (United States)

    Taghizadeh, Ata

    A new class of polymers known as "bioplastics" has emerged and is expanding rapidly. This class consists of polymers that are either bio-based or biodegradable, or both. Among these, polysaccharides, namely starch, are of great interest for several reasons. By gelatinizing starch via plasticizers, it can be processed in the same way as thermoplastic polymers with conventional processing equipment. Hence, these bio-based and biodegradable plastics, with their low source and refinery costs, as well as relatively easy processability, have made them ideal candidates for incorporation into various current plastic products. Four different plasticizers have been chosen here for gelatinization of thermoplastic starch (TPS): glycerol, sorbitol, diglycerol and polyglycerol, with the latter two being used for the first time in such a process. Two methodological categories are used. The first involves a calorimetric method (Differential Scanning Calorimetry) as well as optical microscopy; these are "static" methods where no shear is applied A wide range of starch/water/plasticizer compositions were prepared to explore the gelatinization regime for each plasticizer. The onset and conclusion gelatinization temperatures for sorbitol and glycerol were found to be in the same vicinity, while diglycerol and polyglycerol showed significantly higher transition temperatures. The higher molecular weight and viscosity of polyglycerol allow this transition to occur at an even higher temperature than with diglycerol. This is due to the increase in molecular weight and viscosity of the two new plasticizers, as well as their significant decrease in water solubility. It is demonstrated that the water/plasticizer ratio has a pronounced effect on gelatinization temperatures. When plasticizer content was held constant and water content was increased, it was found that the gelatinization temperature decreased for all the plasticizers. Meanwhile, when the water content was held constant and the

  10. Cellulose biosynthesis in higher plants

    Directory of Open Access Journals (Sweden)

    Krystyna Kudlicka

    2014-01-01

    Full Text Available Knowledge of the control and regulation of cellulose synthesis is fundamental to an understanding of plant development since cellulose is the primary structural component of plant cell walls. In vivo, the polymerization step requires a coordinated transport of substrates across membranes and relies on delicate orientations of the membrane-associated synthase complexes. Little is known about the properties of the enzyme complexes, and many questions about the biosynthesis of cell wall components at the cell surface still remain unanswered. Attempts to purify cellulose synthase from higher plants have not been successful because of the liability of enzymes upon isolation and lack of reliable in vitro assays. Membrane preparations from higher plant cells incorporate UDP-glucose into a glucan polymer, but this invariably turns out to be predominantly β -1,3-linked rather than β -1,4-linked glucans. Various hypotheses have been advanced to explain this phenomenon. One idea is that callose and cellulose-synthase systems are the same, but cell disruption activates callose synthesis preferentially. A second concept suggests that a regulatory protein as a part of the cellulose-synthase complex is rapidly degraded upon cell disruption. With new methods of enzyme isolation and analysis of the in vitro product, recent advances have been made in the isolation of an active synthase from the plasma membrane whereby cellulose synthase was separated from callose synthase.

  11. 13CO2 breath test to measure the hydrolysis of various starch formulations in healthy subjects.

    OpenAIRE

    Hiele, M; Ghoos, Y; Rutgeerts, P; Vantrappen, G; de Buyser, K

    1990-01-01

    13CO2 starch breath test was used to study the effect of physicochemical characteristics of starch digestion. As starch is hydrolysed to glucose, which is subsequently oxidised to CO2, differences in 13CO2 excretion after ingestion of different starch products must be caused by differences in hydrolysis rate. To study the effect of the degree of chain branching, waxy starch, containing 98% amylopectin, was compared with high amylose starch, containing 30% amylopectin, and normal crystalline s...

  12. The cereal starch endosperm development and its relationship with other endosperm tissues and embryo.

    Science.gov (United States)

    Zheng, Yankun; Wang, Zhong

    2015-01-01

    The cereal starch endosperm is the central part of endosperm, and it is rich in starch and protein which are the important resources for human food. The starch and protein are separately accumulated in starch granules and protein bodies. Content and configuration of starch granules and protein bodies affect the quality of the starch endosperm. The development of starch endosperm is mediated by genes, enzymes, and hormones, and it also has a close relationship with other endosperm tissues and embryo. This paper reviews the latest investigations on the starch endosperm and will provide some useful information for the future researches on the development of cereal endosperm.

  13. VAPOR MIXER FOR GELATINIZATION OF STARCH IN LIQUEFYING STATION

    Directory of Open Access Journals (Sweden)

    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 starchstarch 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

  14. Biodegradable packaging materials conception based on starch and polylactic acid (PLA) reinforced with cellulose.

    Science.gov (United States)

    Masmoudi, Fatma; Bessadok, Atef; Dammak, Mohamed; Jaziri, Mohamed; Ammar, Emna

    2016-10-01

    The plastic materials used for packaging are increasing leading to a considerable amount of undegradable solid wastes. This work deals with the reduction of conventional plastics waste and the natural resources preservation by using cellulosic polymers from renewable resources (alfa and luffa). Plasticized starch films syntheses were achieved at a laboratory scale. These natural films showed some very attractive mechanical properties at relatively low plasticizers levels (12 to 17 % by weight). Furthermore, mixtures including polylactic acid polymer (PLA) and cellulose fibers extracted from alfa and luffa were investigated by melt extrusion technique. When used at a rate of 10 %, these fibers improved the mixture mechanical properties. Both developed materials were biodegradable, but the plasticized starch exhibited a faster biodegradation kinetic compared to the PLA/cellulose fibers. These new materials would contribute to a sustainable development and a waste reduction.

  15. Good Housekeeping Implementation for Improving Efficiency in Cassava Starch Industry (Case Study : Margoyoso District, Pati Regency)

    Science.gov (United States)

    Aji, Wijayanto Setyo; Purwanto; Suherman, S.

    2018-02-01

    Cassava starch industry is one of the leading small-medium enterprises (SMEs) in Pati Regency. Cassava starch industry released waste that reduces the quantity of final product and potentially contamined the environment. This study was conducted to observe the feasibility of good housekeeping implementation to reduce waste and at the same time improve efficiency of production process. Good housekeeping opportunities are consideration by three aspect, technical, economy and environmental. Good housekeeping opportunities involved water conservation and waste reduction. These included reuse of water in washing process, improving workers awareness in drying section and packaging section. Implementation of these opportunities can reduce water consumption, reduce wastewater and solid waste generation also increased quantity of final product.

  16. Characterization and Antimicrobial Properties of Gamma Irradiated Starch/ Chitosan/ Ag Nano composites

    International Nuclear Information System (INIS)

    Khalil, S.A.; Hassan, M.S.; Ali, N.M.

    2016-01-01

    Composites based on different ratios of starch and chitosan, in the presence of a constant amount of silver nanoparticles (AgNPs), were prepared in the form of thin films by casting solutions. The gamma irradiated composites were characterized in terms of solution viscosity, FTIR, XRD, TGA and SEM. In addition, the antimicrobial activity of the prepared composites against different microorganisms was investigated. The results showed that the increase of irradiation dose more than 5 kGy leads to a decrease in the composite solution viscosity, the overall crystallinity, thermal stability and antimicrobial activity of the prepared films. The prepared starch based composites were applied to cotton samples to demonstrate the antimicrobial finishing. Acceptable antimicrobial results against both the tested pathogenic bacteria and in burial test were obtained.

  17. Lead poisoning

    Science.gov (United States)

    ... drinking water in homes containing pipes that were connected with lead solder . Although new building codes require ... lead in their bodies when they put lead objects in their mouths, especially if they swallow those ...

  18. Lead Poisoning

    Science.gov (United States)

    Lead is a metal that occurs naturally in the earth's crust. Lead can be found in all parts of our ... from human activities such as mining and manufacturing. Lead used to be in paint; older houses may ...

  19. Biosynthesis of Tropolones in Streptomyces spp: Interweaving Biosynthesis and Degradation of Phenylacetic Acid and Hydroxylations on Tropone Ring.

    Science.gov (United States)

    Chen, Xuefei; Xu, Min; Lü, Jin; Xu, Jianguo; Wang, Yemin; Lin, Shuangjun; Deng, Zixin; Tao, Meifeng

    2018-04-13

    Tropolonoids are important natural products that contain a unique seven-membered aromatic tropolone core and exhibit remarkable biological activities. 3,7-Dihydroxytropolone (DHT) isolated from Streptomyces species is a multiply hydroxylated tropolone exhibiting antimicrobial, anticancer, and antiviral activities. Herein, we determined the DHT biosynthetic pathway by heterologous expression, gene deletion, and bioconversion. Nine trl genes and some of the aerobic phenylacetic acid degradation pathway genes ( paa ) located outside of the trl biosynthetic gene cluster are required for the heterologous production of DHT. The trlA gene encodes a single-domain protein homologous to the C-terminal enoyl-CoA hydratase domain of PaaZ. TrlA truncates the phenylacetic acid catabolic pathway and redirects it towards the formation of heptacyclic intermediates. TrlB is a 3-deoxy-D-arabino-heptulosonic acid-7-phosphate (DAHP) synthase homolog. TrlH is an unusual bifunctional protein bearing an N-terminal prephenate dehydratase domain and a C-terminal chorismate mutase domain. TrlB and TrlH enhanced de novo biosynthesis of phenylpyruvate, thereby providing abundant precursor for the prolific production of DHT in Streptomyces Six seven-membered carbocyclic compounds were identified from the gene deletion mutants of trlC , trlD , trlE , and trlF Four of these chemicals, including 1,4,6-cycloheptatriene-1-carboxylic acid, tropone, tropolone and 7-hydroxytropolone, were verified as key biosynthetic intermediates. TrlF is required for the conversion of 1,4,6-cycloheptatriene-1-carboxylic acid into tropone. Monooxygenases TrlE and TrlCD catalyze the regioselective hydroxylations of tropone to afford DHT. This study reveals a natural association of anabolism of chorismate and phenylpyruvate, catabolism of phenylacetic acid, and biosynthesis of tropolones in Streptomyces spp. IMPORTANCE Tropolonoids are promising drug lead compounds because of their versatile bioactivities attributed to

  20. Functional Characterization of Bean Zaragoza Starch (Phaseolus Lunatus L. and Quantification of the Resistant Starch

    Directory of Open Access Journals (Sweden)

    Piedad M. Montero-Castillo

    2013-06-01

    Full Text Available Legumes are a potential source of starch, representing between 30 and 50% of its dry weight, this is an essential energy source for humans. Currently its use is widespread in the food industry as an additive or raw material in food compounds, due to its nutritional, functional properties as a thickening agent and stabilizer of suspensions and dispersions. We evaluated several functional properties of starch variety zaragoza red bean, was obtained initial gelatinization temperature and final (71°C (81°C respectively, the solubility was 8.3% at 90°C, swelling power was 6.6% at 80°C, and water retention capacity was 4.4% at 80°C. The apparent viscosity was evaluated between 20 and 75 °C giving as results viscosities between 1.096 and 0.98 Cp respectively. The results showed that the tested temperatures significantly affect the solubility, swelling power, water holding capacity and viscosity of the starch. The amylose and amylopectin content was 21.1% and 78.19%. Finally, was obtained 9,24% resistant starch and compared with other conventional non starchy sources in order to acquire new knowledge about this material native to the Colombian Caribbean coast.

  1. 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.

  2. Agrobacterium Mediated Transient Gene Silencing (AMTS) in Stevia rebaudiana: Insights into Steviol Glycoside Biosynthesis Pathway

    Science.gov (United States)

    Guleria, Praveen; Yadav, Sudesh Kumar

    2013-01-01

    Background Steviol glycoside biosynthesis pathway has emerged as bifurcation from ent-kaurenoic acid, substrate of methyl erythritol phosphate pathway that also leads to gibberellin biosynthesis. However, the genetic regulation of steviol glycoside biosynthesis has not been studied. So, in present study RNA interference (RNAi) based Agrobacterium mediated transient gene silencing (AMTS) approach was followed. SrKA13H and three SrUGTs (SrUGT85C2, SrUGT74G1 and SrUGT76G1) genes encoding ent-kaurenoic acid-13 hydroxylase and three UDP glycosyltransferases of steviol glycoside biosynthesis pathway were silenced in Stevia rebaudiana to understand its molecular mechanism and association with gibberellins. Methodology/Principal Findings RNAi mediated AMTS of SrKA13H and three SrUGTs has significantly reduced the expression of targeted endogenous genes as well as total steviol glycoside accumulation. While gibberellins (GA3) content was significantly enhanced on AMTS of SrUGT85C2 and SrKA13H. Silencing of SrKA13H and SrUGT85C2 was found to block the metabolite flux of steviol glycoside pathway and shifted it towards GA3 biosynthesis. Further, molecular docking of three SrUGT proteins has documented highest affinity of SrUGT76G1 for the substrates of alternate pathways synthesizing steviol glycosides. This could be a plausible reason for maximum reduction in steviol glycoside content on silencing of SrUGT76G1 than other genes. Conclusions SrKA13H and SrUGT85C2 were identified as regulatory genes influencing carbon flux between steviol glycoside and gibberellin biosynthesis. This study has also documented the existence of alternate steviol glycoside biosynthesis route. PMID:24023961

  3. Agrobacterium mediated transient gene silencing (AMTS in Stevia rebaudiana: insights into steviol glycoside biosynthesis pathway.

    Directory of Open Access Journals (Sweden)

    Praveen Guleria

    Full Text Available Steviol glycoside biosynthesis pathway has emerged as bifurcation from ent-kaurenoic acid, substrate of methyl erythritol phosphate pathway that also leads to gibberellin biosynthesis. However, the genetic regulation of steviol glycoside biosynthesis has not been studied. So, in present study RNA interference (RNAi based Agrobacterium mediated transient gene silencing (AMTS approach was followed. SrKA13H and three SrUGTs (SrUGT85C2, SrUGT74G1 and SrUGT76G1 genes encoding ent-kaurenoic acid-13 hydroxylase and three UDP glycosyltransferases of steviol glycoside biosynthesis pathway were silenced in Stevia rebaudiana to understand its molecular mechanism and association with gibberellins.RNAi mediated AMTS of SrKA13H and three SrUGTs has significantly reduced the expression of targeted endogenous genes as well as total steviol glycoside accumulation. While gibberellins (GA3 content was significantly enhanced on AMTS of SrUGT85C2 and SrKA13H. Silencing of SrKA13H and SrUGT85C2 was found to block the metabolite flux of steviol glycoside pathway and shifted it towards GA3 biosynthesis. Further, molecular docking of three SrUGT proteins has documented highest affinity of SrUGT76G1 for the substrates of alternate pathways synthesizing steviol glycosides. This could be a plausible reason for maximum reduction in steviol glycoside content on silencing of SrUGT76G1 than other genes.SrKA13H and SrUGT85C2 were identified as regulatory genes influencing carbon flux between steviol glycoside and gibberellin biosynthesis. This study has also documented the existence of alternate steviol glycoside biosynthesis route.

  4. Alginate Biosynthesis in Azotobacter vinelandii: Overview of Molecular Mechanisms in Connection with the Oxygen Availability

    Directory of Open Access Journals (Sweden)

    Ivette Pacheco-Leyva

    2016-01-01

    Full Text Available The Gram-negative bacterium Azotobacter vinelandii can synthetize the biopolymer alginate that has material properties appropriate for plenty of applications in industry as well as in medicine. In order to settle the foundation for improving alginate production without compromising its quality, a better understanding of the polymer biosynthesis and the mechanism of regulation during fermentation processes is necessary. This knowledge is crucial for the development of novel production strategies. Here, we highlight the key aspects of alginate biosynthesis that can lead to producing an alginate with specific material properties with particular focus on the role of oxygen availability linked with the molecular mechanisms involved in the alginate production.

  5. Relationship between gas production and starch degradation in feed samples

    NARCIS (Netherlands)

    Chai, W.Z.; Gelder, van A.H.; Cone, J.W.

    2004-01-01

    An investigation was completed of the possibilities to estimate starch fermentation in rumen fluid using the gas production technique by incubating the total sample. Gas production from six starchy feed ingredients and eight maize silage samples were recorded and related to starch degradation

  6. Packing and Cohesive Properties of Some Locally Extracted Starches

    African Journals Online (AJOL)

    ... properties of the particles affect the packing and cohesive properties of the starches, and are important in predicting the behaviour of the starches during handling and use in pharmaceutical preparations. These properties need to be closely controlled in pre-formulation studies. Keywords: Packing and cohesive properties, ...

  7. 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.

  8. Preparation and In vitro Digestibility of Corn Starch Phosphodiester ...

    African Journals Online (AJOL)

    Purpose: To optimize the process conditions and analyze in vitro digestibility of corn starch phosphodiester prepared by sodium trimetaphosphate (STMP). Methods: By using response surface method, the effects of STMP concentration, pH, esterification temperature, and urea addition on digestion resistance of corn starch ...

  9. Lima Bean Starch-Based Hydrogels | Oladebeye | Nigerian Journal ...

    African Journals Online (AJOL)

    Hydrogels were prepared by crosslinking native lima bean starch and polyvinyl alcohol (PVA) with glutaraldehyde (GA) at varying proportions in an acidic medium. The native starch (N-LBS) and hydrogels (L-GA (low glutaraldehyde) and H-GA (high glutaraldehyde)) were examined for their water absorption capacity (WAC) ...

  10. Evaluation of binder and disintegrant properties of starch derived ...

    African Journals Online (AJOL)

    The aim of the study was to formulate metronidazole tablets using starch from Xanthosoma sagittifolium as binder and disintegrant in metronidazole tablets. Metronidazole tablets were produced by wet granulation method using X. sagittifolium starch as binder at concentrations of 5, 10, 15 and 20% w/w, and as disintegrant ...

  11. Biodegradation and moisture uptake modified starch-filled Linear ...

    African Journals Online (AJOL)

    Sixteen different modified-cassava starch-LLDPE blends containing starch in the range of 10-40% by weight were prepared. Calcium chloride, D-glucose, chloroform and alumina were differently used as modifying agents. The Moisture uptake and biodegradation of each of the composites were investigated. Both of these ...

  12. Effects of Native and Pregelatinised Fonio starches on compression ...

    African Journals Online (AJOL)

    Native and modified (pregelatinised) Fonio starches were evaluated as binding agents in comparison with maize starch B.P. in paracetamol tablet formulations. Compressional properties of the formulations were analyzed using density measurements and assessed by the compression equation of Heckel. The mechanical ...

  13. The kinetics of the acetylation of gelatinised potato starch

    NARCIS (Netherlands)

    de Graaf, R.A.; Broekroelofs, G.A.; Janssen, L.P.B.M.; Beenackers, A.A C M

    1995-01-01

    The reaction rates, in the base-catalysed acetylation of gelatinised aqueous starch (4 wt%), by vinylacetate (ViAc), were investigated in a semibatch reactor at temperatures ranging from 20 to 50 degrees C. The desired starch acetylation reaction is accompanied by an undesired parallel

  14. Immobilization of urease on grafted starch by radiation method

    International Nuclear Information System (INIS)

    Nguyenanh Dung; Nguyendinh Huyen

    1995-01-01

    The acrylamide was grafted by radiation onto starch which is a kind of polymeric biomaterial. The urease was immobilized on the grafted starch. Some experiments to observe the quantitative relationships between the percent graft and the activity of immobilized enzyme were determined. The enzyme activity was maintained by more than seven batch enzyme reactions. (author)

  15. Crystallinity in starch plastics: consequences for material properties

    NARCIS (Netherlands)

    Soest, van J.J.G.; Vliegenthart, J.F.G.

    1997-01-01

    The processing of starches with biodegradable additives has made biodegradable plastics suitable for a number of applications. Starch plastics are partially crystalline as a result of residual crystallinity and the recrystallization of amylose and amylopectin. Such crystallinity is a key determinant

  16. Surface effects in the acetylation of granular potato starch

    NARCIS (Netherlands)

    Steeneken, P.A.M.; Woortman, A.J.J.

    2008-01-01

    The occurrence of surface effects in the acetylation of granular potato starch with acetic anhydride to degrees of substitution 0.04-0.2 was studied by two different approaches. The first approach involved the fractionation of granular starch acetates into five different size classes and analysis of

  17. Physicochemical and functional properties of starches of two quality ...

    African Journals Online (AJOL)

    SARAH

    2013-06-30

    Jun 30, 2013 ... water expelled from white QPM starch was 40.39% at -15°C and 37.05% at 4°C after the first week of storage ... include starch, high-fructose corn syrup and livestock ... associations of 40–70 glucose units whereas.

  18. 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.

  19. 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; ...

  20. Milk glucosidase activity enables suckled pup starch digestion

    Science.gov (United States)

    Starch requires six enzymes for digestion to free glucose: two amylases (salivary and pancreatic) and four mucosal maltase activities; sucrase-isomaltase and maltase-glucoamylase. All are deficient in suckling rodents. The objective of this study is to test (13)C-starch digestion before weaning by m...

  1. Acetylated starch of Ofada rice as a sustained polymer in ...

    African Journals Online (AJOL)

    Objectives: To formulate and evaluate repaglinide microspheres using acetylated starch of the indigenous rice species Oryza glaberrima Steud (Ofada) as polymer. Materials and Methods: Ofada rice starch was acetylated with acetic anhydride in pyridine (DS 2.68) and characterized for morphology (Scanning electron ...

  2. 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.

  3. CONTINUOUS PRODUCTION OF HYDROXYPROPYL STARCH IN A STATIC MIXER REACTOR

    NARCIS (Netherlands)

    LAMMERS, G; STAMHUIS, EJ; BEENACKERS, AACM

    A novel type of reactor for the chemical derivatization of starch pastes is presented. The design is based on the application of static mixers. The reactor shows excellent plug flow behaviour with a Peclet number of about 100. The viscosity behaviour of concentrated starch pastes in the static mixer

  4. Starch modification with microbial alpha-glucanotransferase enzymes

    NARCIS (Netherlands)

    van der Maarel, Marc J. E. C.; Leemhuis, Hans

    2013-01-01

    Starch is an agricultural raw material used in many food and industrial products. It is present in granules that vary in shape in the form of amylose and amylopectin. Starch-degrading enzymes are used on a large scale in the production of sweeteners (high fructose corn syrup) and concentrated

  5. Investigation on modification of cassava starch using active ...

    African Journals Online (AJOL)

    Effects of ginger grates at concentrations of l, 5 and 20 g per 150 g of cassava starch suspension in 200 ml of water at room temperature were investigated in order to evaluate the potentials of active components of the ginger in modifying pasting and some physicochemical properties of the starch. Pasting properties of the ...

  6. 13 Comparative Effects of Cassava Starch and Simple Sugar in ...

    African Journals Online (AJOL)

    Arc. Usman A. Jalam

    Abstract. Comparative effects of simple laboratory quality sugar and cassava starch on grade C35 concrete were studied in the laboratory. The simple white sugar was used at concentrations of 0 to 1% by weight of cement in concrete cured at 3, 7, 14 and 28 days using ordinary Portland cement. Cassava starch of the same ...

  7. Kinetics of the gas-solid hydroxyethylation of potato starch

    NARCIS (Netherlands)

    Kuipers, N.J M; Beenackers, A.A C M

    The kinetics of the reaction between gaseous ethylene oxide and semidry granular potato starch was studied in a pressure-controlled semibatch reactor with and without impregnation of the starch with the catalyst sodium hydroxide. Four parallel reactions are involved: the catalyzed (with reaction

  8. Effect of cassava starch substituion on the functional and sensory ...

    African Journals Online (AJOL)

    The starch cake was rinsed four times, dried in the oven at 40oC for 24 hrs, milled and sieved. The cassava starch was used to substitute 10, 20, 30, 40 and 50% of trifoliate yam flour. The control white yam (Dioscorea rotundata) tubers were peeled, washed and diced. The diced yam tubers were parboiled at temperature of ...

  9. Synthesis of graft copolymers onto starch and its semiconducting properties

    Directory of Open Access Journals (Sweden)

    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

  10. Enzymatic Modification of Corn Starch Influences Human Fecal Fermentation Profiles.

    Science.gov (United States)

    Dura, Angela; Rose, Devin J; Rosell, Cristina M

    2017-06-14

    Enzymatically modified starches have been widely used in food applications to develop new products, but information regarding digestion and fecal fermentation of these products is sparse. The objective of this study was to determine the fermentation properties of corn starch modified with α-amylase, amyloglucosidase, or cyclodextrin glycosyltransferase and the possible role of hydrolysis products. Samples differed in their digestibility and availability to be fermented by the microbiota, resulting in differences in microbial metabolites produced during in vitro fermentation. The presence or absence of hydrolysis products and gelatinization affected starch composition and subsequent metabolite production by the microbiota. Amyloglucosidase-treated starch led to the greatest production of short- and branched-chain fatty acid production by the microbiota. Results from this study could be taken into consideration to confirm the possible nutritional claims and potential health benefits of these starches as raw ingredients for food development.

  11. Irradiation of starches for industrial uses: Chemical and physical effects

    International Nuclear Information System (INIS)

    Gonzalez, Maria E.

    1999-01-01

    Corn and cassava starches have been irradiated with gamma doses from 10 to 180 kGy and pastes have been prepared by boiling the starches in water. The rheological properties of the pastes have been determined showing that the 10 kGy dose reduces sharply the viscosity of the aqueous pastes. The solubility of the irradiated starches has been also studied. The cassava starch irradiated with 180 kGy is soluble in boiling water and remains soluble at room temperature. After some considerations on the chemical effects of the irradiation it is concluded that the irradiation technique is suitable to replace the chemical treatment in many industrial applications of the starch. (author)

  12. Effect of starch binder on charcoal briquette properties

    Science.gov (United States)

    Borowski, Gabriel; Stępniewski, Witold; Wójcik-Oliveira, Katarzyna

    2017-10-01

    The paper shows the results of a study on the effect of starch binder on the mechanical, physical and burning properties of charcoal briquettes. Two types of binders were repeatedly used to make briquettes of native wheat starch and modified wheat starch, at 8% of the whole. Briquetting was performed in a roller press unit, and pillow-shaped briquettes were made. The moisture of the mixed material ranged from 28 to 32%. The product, whether the former or the latter, was characterized by very good mechanical properties and satisfactory physical properties. Moreover, the type of starch binder had no effect on toughness, calorific heating value, volatiles, fixed carbon content and ash content. However, the combustion test showed quite different burning properties. As briquettes should have short firing up time and lower smokiness, as well as high maximum temperature and long burning time, we have concluded that briquettes with native wheat starch as a binder are more appropriate for burning in the grill.

  13. 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.

  14. Effect of Ultrasound on Physicochemical Properties of Wheat Starch

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, Jim

    2013-11-30

    structure of ADP- Glucose pyrophosphorylase from potato in its inhibited conformation, and bound to both ATP and ADP-glucose. In addition, we have determined the first structure of glycogen synthase in its "closed", catalytically active conformation bound to ADP-glucose. We also determined the structure of glycogen synthase bound to malto-oligosaccharides, showing for the first time that an enzyme in the starch biosynthetic pathway recognizes glucans not just in its active site but on binding sites on the surface of the enzyme ten’s of Angstroms from the active site. In addition our structure of a glycogen branching enzyme bound to malto-oligosaccharides identified seven distinct binding sites distributed about the surface of the enzyme. We will now determine the function of these sites to get a molecular-level picture of exactly how these enzymes interact with their polymeric substrates and confer specificity leading to the complex structure of the starch granule. We will extend our studies to other isoforms of the enzymes, to understand how their structures give rise to their distinct function. Our goal is to understand what accounts for the various functional differences between SS and SBE isoforms at a molecular level.

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

    NARCIS (Netherlands)

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

    2010-01-01

    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

  17. 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

  18. 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)

  19. 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)

  20. Biosynthesis and function of chondroitin sulfate.

    Science.gov (United States)

    Mikami, Tadahisa; Kitagawa, Hiroshi

    2013-10-01

    Chondroitin sulfate proteoglycans (CSPGs) are principal pericellular and extracellular components that form regulatory milieu involving numerous biological and pathophysiological phenomena. Diverse functions of CSPGs can be mainly attributed to structural variability of their polysaccharide moieties, chondroitin sulfate glycosaminoglycans (CS-GAG). Comprehensive understanding of the regulatory mechanisms for CS biosynthesis and its catabolic processes is required in order to understand those functions. Here, we focus on recent advances in the study of enzymatic regulatory pathways for CS biosynthesis including successive modification/degradation, distinct CS functions, and disease phenotypes that have been revealed by perturbation of the respective enzymes in vitro and in vivo. Fine-tuned machineries for CS production/degradation are crucial for the functional expression of CS chains in developmental and pathophysiological processes. Control of enzymes responsible for CS biosynthesis/catabolism is a potential target for therapeutic intervention for the CS-associated disorders. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Starch characteristics of transgenic wheat (Triticum aestivum L.) overexpressing the Dx5 high molecular weight glutenin subunit are substantially equivalent to those in nonmodified wheat.

    Science.gov (United States)

    Beckles, Diane M; Tananuwong, Kanitha; Shoemaker, Charles F

    2012-04-01

    The effects of engineering higher levels of the High Molecular Weight Glutenin Dx5 subunit on starch characteristics in transgenic wheat (Triticum aestivum L.) grain were evaluated. This is important because of the interrelationship between starch and protein accumulation in grain, the strong biotechnological interest in modulating Dx5 levels and the increasing likelihood that transgenic wheat will be commercialized in the U.S. Unintended effects of Dx5 overexpression on starch could affect wheat marketability and therefore should be examined. Two controls with native levels of Dx5 were used: (i) the nontransformed Bobwhite cultivar, and (ii) a transgenic line (Bar-D) expressing a herbicide resistant (bar) gene, and they were compared with 2 transgenic lines (Dx5G and Dx5J) containing bar and additional copies of Dx5. There were few changes between Bar-D and Dx5G compared to Bobwhite. However, Dx5J, the line with the highest Dx5 protein (×3.5) accumulated 140% more hexose, 25% less starch and the starch had a higher frequency of longer amylopectin chains. These differences were not of sufficient magnitude to influence starch functionality, because granule morphology, crystallinity, amylose-to-amylopectin ratio, and the enthalpy of starch gelatinization and the amylose-lipid complex melting were similar to the control (P > 0.05). This overall similarity was borne out by Partial Least Squares-Discriminant Function Analysis, which could not distinguish among genotypes. Collectively our data imply that higher Dx5 can affect starch accumulation and some aspects of starch molecular structure but that the starches of the Dx5 transgenic wheat lines are substantially equivalent to the controls. Transgenic manipulation of biochemical pathways is an effective way to enhance food sensory quality, but it can also lead to unintended effects. These spurious changes are a concern to Government Regulatory Agencies and to those Industries that market the product. In this study we

  2. Prebiotic properties of potato starch dextrins

    Directory of Open Access Journals (Sweden)

    Renata Barczyńska

    2015-09-01

    Full Text Available The objective of the present study was to compare the prebiotic properties of starch dextrins, that is, resistant dextrins obtained from potato starch in the process of simultaneous thermolysis and chemical modification, which were selected based on previous research. Both prepared dextrins met the definition criterion of dietary fiber and also the basic prebiotic criterion – they were not degraded by the digestive enzymes of the initial sections of the gastrointestinal tract. The growth of probiotic lactobacilli and bifidobacteria, as well as Escherichia coli, Enterococcus, Bacteroides, and Clostridium strains isolated from feces of healthy people, showed that both studied dextrins were utilized as a source of assimilable carbon and energy by the strains. Furthermore, better growth (higher numbers of cells counts of probiotic bacteria than those of fecal isolates indicated that the studied resistant dextrins showed a selective effect. Both dextrins might be considered as substances with prebiotic properties due to their chemical and physical properties and selectivity towards the studied probiotic bacterial strains.

  3. Triterpenoid biosynthesis in Euphorbia lathyris latex

    International Nuclear Information System (INIS)

    Hawkins, D.R.

    1987-11-01

    The structures of triterpenols, not previously been known, from Euphorbia lathyris latex are reported. A method for quantifying very small amounts of these compounds was developed. Concerning the biochemistry of the latex, no exogenous cofactors were required for the biosynthesis and the addition of compounds such as NADPAH and ATP do not stimulate the biosynthesis. The addition of DTE or a similar anti-oxidant was found to help reduce the oxidation of the latex, thus increasing the length of time that the latex remains active. The requirement of a divalent cation and the preference for Mn in the pellet was observed. The effect of several inhibitors on the biosynthesis of the triterpenoids was examined. Mevinolin was found to inhibit the biosynthesis of the triterpenoids from acetate, but not mevalonate. A dixon plot of the inhibition of acetate incorporation showed an I 50 concentration of 3.2 μM. Fenpropimorph was found to have little or no effect on the biosynthesis. Tridemorph was found to inhibit the biosynthesis of all of the triterpenoids with an I 50 of 4 μM. It was also observed that the cyclopropyl containing triterpenols, cycloartenol and 24-methylenecycloartenol were inhibited much more strongly than those containing an 8-9 double bond, lanosterol and 24-methylenelanosterol. The evidence indicates, but does not definetely prove, that lanosterol and 24-methylenelanosterol are not made from cycloartenol and 24-methylenecycloartenol via a ring-opening enzyme such as cycloeucalenol-obtusifoliol isomerase. The possibilty that cycloartenol is made via lanosterol was investigated by synthesizing 4-R-4- 3 H-mevalonic acid and incubating latex with a mixture of this and 14 C-mevalonic acid. From the 3 H/ 14 C ratio it was shown that cycloartenol and 24-methylenecycloartenol are not made via an intermediate containing as 8-9 double bond. 88 refs., 15 figs., 30 tabs

  4. Triterpenoid biosynthesis in Euphorbia lathyris latex

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, D.R.

    1987-11-01

    The structures of triterpenols, not previously been known, from Euphorbia lathyris latex are reported. A method for quantifying very small amounts of these compounds was developed. Concerning the biochemistry of the latex, no exogenous cofactors were required for the biosynthesis and the addition of compounds such as NADPAH and ATP do not stimulate the biosynthesis. The addition of DTE or a similar anti-oxidant was found to help reduce the oxidation of the latex, thus increasing the length of time that the latex remains active. The requirement of a divalent cation and the preference for Mn in the pellet was observed. The effect of several inhibitors on the biosynthesis of the triterpenoids was examined. Mevinolin was found to inhibit the biosynthesis of the triterpenoids from acetate, but not mevalonate. A dixon plot of the inhibition of acetate incorporation showed an I/sub 50/ concentration of 3.2 ..mu..M. Fenpropimorph was found to have little or no effect on the biosynthesis. Tridemorph was found to inhibit the biosynthesis of all of the triterpenoids with an I/sub 50/ of 4 ..mu..M. It was also observed that the cyclopropyl containing triterpenols, cycloartenol and 24-methylenecycloartenol were inhibited much more strongly than those containing an 8-9 double bond, lanosterol and 24-methylenelanosterol. The evidence indicates, but does not definetely prove, that lanosterol and 24-methylenelanosterol are not made from cycloartenol and 24-methylenecycloartenol via a ring-opening enzyme such as cycloeucalenol-obtusifoliol isomerase. The possibilty that cycloartenol is made via lanosterol was investigated by synthesizing 4-R-4-/sup 3/H-mevalonic acid and incubating latex with a mixture of this and /sup 14/C-mevalonic acid. From the /sup 3/H//sup 14/C ratio it was shown that cycloartenol and 24-methylenecycloartenol are not made via an intermediate containing as 8-9 double bond. 88 refs., 15 figs., 30 tabs.

  5. Phenolic Amides Are Potent Inhibitors of De Novo Nucleotide Biosynthesis.

    Science.gov (United States)

    Pisithkul, Tippapha; Jacobson, Tyler B; O'Brien, Thomas J; Stevenson, David M; Amador-Noguez, Daniel

    2015-09-01

    An outstanding challenge toward efficient production of biofuels and value-added chemicals from plant biomass is the impact that lignocellulose-derived inhibitors have on microbial fermentations. Elucidating the mechanisms that underlie their toxicity is critical for developing strategies to overcome them. Here, using Escherichia coli as a model system, we investigated the metabolic effects and toxicity mechanisms of feruloyl amide and coumaroyl amide, the predominant phenolic compounds in ammonia-pretreated biomass hydrolysates. Using metabolomics, isotope tracers, and biochemical assays, we showed that these two phenolic amides act as potent and fast-acting inhibitors of purine and pyrimidine biosynthetic pathways. Feruloyl or coumaroyl amide exposure leads to (i) a rapid buildup of 5-phosphoribosyl-1-pyrophosphate (PRPP), a key precursor in nucleotide biosynthesis, (ii) a rapid decrease in the levels of pyrimidine biosynthetic intermediates, and (iii) a long-term generalized decrease in nucleotide and deoxynucleotide levels. Tracer experiments using (13)C-labeled sugars and [(15)N]ammonia demonstrated that carbon and nitrogen fluxes into nucleotides and deoxynucleotides are inhibited by these phenolic amides. We found that these effects are mediated via direct inhibition of glutamine amidotransferases that participate in nucleotide biosynthetic pathways. In particular, feruloyl amide is a competitive inhibitor of glutamine PRPP amidotransferase (PurF), which catalyzes the first committed step in de novo purine biosynthesis. Finally, external nucleoside supplementation prevents phenolic amide-mediated growth inhibition by allowing nucleotide biosynthesis via salvage pathways. The results presented here will help in the development of strategies to overcome toxicity of phenolic compounds and facilitate engineering of more efficient microbial producers of biofuels and chemicals. Copyright © 2015, Pisithkul et al.

  6. Phenolic Amides Are Potent Inhibitors of De Novo Nucleotide Biosynthesis

    Science.gov (United States)

    Pisithkul, Tippapha; Jacobson, Tyler B.; O'Brien, Thomas J.; Stevenson, David M.

    2015-01-01

    An outstanding challenge toward efficient production of biofuels and value-added chemicals from plant biomass is the impact that lignocellulose-derived inhibitors have on microbial fermentations. Elucidating the mechanisms that underlie their toxicity is critical for developing strategies to overcome them. Here, using Escherichia coli as a model system, we investigated the metabolic effects and toxicity mechanisms of feruloyl amide and coumaroyl amide, the predominant phenolic compounds in ammonia-pretreated biomass hydrolysates. Using metabolomics, isotope tracers, and biochemical assays, we showed that these two phenolic amides act as potent and fast-acting inhibitors of purine and pyrimidine biosynthetic pathways. Feruloyl or coumaroyl amide exposure leads to (i) a rapid buildup of 5-phosphoribosyl-1-pyrophosphate (PRPP), a key precursor in nucleotide biosynthesis, (ii) a rapid decrease in the levels of pyrimidine biosynthetic intermediates, and (iii) a long-term generalized decrease in nucleotide and deoxynucleotide levels. Tracer experiments using 13C-labeled sugars and [15N]ammonia demonstrated that carbon and nitrogen fluxes into nucleotides and deoxynucleotides are inhibited by these phenolic amides. We found that these effects are mediated via direct inhibition of glutamine amidotransferases that participate in nucleotide biosynthetic pathways. In particular, feruloyl amide is a competitive inhibitor of glutamine PRPP amidotransferase (PurF), which catalyzes the first committed step in de novo purine biosynthesis. Finally, external nucleoside supplementation prevents phenolic amide-mediated growth inhibition by allowing nucleotide biosynthesis via salvage pathways. The results presented here will help in the development of strategies to overcome toxicity of phenolic compounds and facilitate engineering of more efficient microbial producers of biofuels and chemicals. PMID:26070680

  7. Convergent Evolution of Ergothioneine Biosynthesis in Cyanobacteria.

    Science.gov (United States)

    Liao, Cangsong; Seebeck, Florian P

    2017-11-02

    Biosynthesis of N-α-trimethyl-2-thiohistidine (ergothioneine) is a frequent trait in cyanobacteria. This sulfur compound may provide essential relief from oxidative stress related to oxygenic photosynthesis. The central steps in ergothioneine biosynthesis are catalyzed by a histidine methyltransferase and an iron-dependent sulfoxide synthase. In this report, we present evidence that some cyanobacteria recruited and adapted a sulfoxide synthase from a different biosynthetic pathway to make ergothioneine. The discovery of a second origin of ergothioneine production underscores the physiological importance of this metabolite and highlights the evolutionary malleability of the thiohistidine biosynthetic machinery. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Method for determining heterologous biosynthesis pathways

    KAUST Repository

    Gao, Xin

    2017-08-10

    The present invention relates to a method and system for dynamically analyzing, determining, predicting and displaying ranked suitable heterologous biosynthesis pathways for a specified host. The present invention addresses the problem of finding suitable pathways for the endogenous metabolism of a host organism because the efficacy of heterologous biosynthesis is affected by competing endogenous pathways. The present invention is called MRE (Metabolic Route Explorer), and it was conceived and developed to systematically and dynamically search for, determine, analyze, and display promising heterologous pathways while considering competing endogenous reactions in a given host organism.

  9. The expanding universe of alkaloid biosynthesis.

    Science.gov (United States)

    De Luca, V; Laflamme, P

    2001-06-01

    Characterization of many of the major gene families responsible for the generation of central intermediates and for their decoration, together with the development of large genomics and proteomics databases, has revolutionized our capability to identify exotic and interesting natural-product pathways. Over the next few years, these tools will facilitate dramatic advances in our knowledge of the biosynthesis of alkaloids, which will far surpass that which we have learned in the past 50 years. These tools will also be exploited for the rapid characterization of regulatory genes, which control the development of specialized cell factories for alkaloid biosynthesis.

  10. Biosynthesis of silver nanoparticles by Aspergillus niger , Fusarium ...

    African Journals Online (AJOL)

    ... scanning electron microscope (SEM). Results indicate the synthesis of silver nanoparticles in the reaction mixture. The synthesis of nanoparticles would be suitable for developing a microbial nanotechnology biosynthesis process for mass scale production. Keywords: Silver nanoparticles, biosynthesis, fungi, Aspergillus.

  11. Lead poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Beijers, J A

    1952-01-01

    Three cases of acute lead poisoning of cattle herds via ingestion are reported, and reference is made to several other incidents of lead in both humans and animals. The quantity of lead which was found in the livers of the dead cows varied from 6.5 to 19 mg/kg, while 1160 mg/kg of lead in the liver was found for a young cow which was poisoned experimentally with 5 gms of lead acetate per day; hence, there appears to be great variability in the amounts deposited that can lead to intoxication and death. No evidence was found for a lead seam around the teeth, prophyrinuria, or basophil granules in the erythrocytes during acute or chronic lead poisoning of cattle or horses examined. Reference is made to attempts of finding the boundary line between increased lead absorption and lead intoxication in humans, and an examination of 60 laborers in an offset-printing office containing a great deal of inhalable lead (0.16 to 1.9 mg/cu m air) is reviewed. Physical deviation, basophylic granulation of erythrocytes, increased lead content of the urine, and porphyrinuria only indicate an increased absorption of lead; the use of the term intoxication is justified if, in addition, there are complaints of lack of appetite, constipation, fatigue, abdominal pain, and emaciation.

  12. Structural and physical effects of aroma compound binding to native starch granules

    DEFF Research Database (Denmark)

    Jørgensen, Anders Dysted; Jensen, Susanne L.; Ziegler, Gregory

    2012-01-01

    , potato and pea starches used represent different typical structural and chemical starch characteristics. Retention of the different aroma compounds varied from a few to one hundred percent and starch was found to induce as well as reduce aroma evaporation depending on the aroma compound and the starch...

  13. Effect of dietary starch source and concentration on equine fecal microbiota

    Science.gov (United States)

    Starch from corn is less susceptible to equine small intestinal digestion than starch from oats, and starch that reaches the hindgut can be utilized by the microbiota. The objective of the current study was to examine the effects of starch source on equine fecal microbiota. Thirty horses were assig...

  14. Hydroxypropylation of pigeon pea (cajanus cajan) starch: Preparation, functional characterizations and enzymatic digestibility

    International Nuclear Information System (INIS)

    Lawal, O.S.

    2008-05-01

    Hydroxypropyl starch derivatives were prepared from pigeon pea starch (NPPS) which is an unconventional starch source. Functional parameters and characterization of both native and modified starches were carried out. The starch granules appeared oval or elliptical in shape with sizes ranging from 7 - 40 μm in width and 10 . 30 μm in length. Hydroxypropylation did not alter the shape of the starch granules in a pronounced way. Generally, the x-ray diffractograms of both native and hydroxypropyl derivatives showed the 'C' pattern. However, slight reductions were observed in the intensity of starches after modification. At all temperatures studied (30 - 90 deg. C), swelling and solubility of hydroxypropylated starches were higher than the NPPS. Progressive increases in swelling capacity and solubility were observed as the MS increased among the hydroxypropylated starches. Hydroxypropylation reduced starch paste turbidity on storage. Also, studies showed that syneresis reduced after hydroxypropylation. In addition, syneresis reduced as the MS of the hydroxypropyl starches increased. The results indicate that pasting temperature and peak temperature reduced after modification but peak viscosity increased in hydroxypropylated starch derivatives compared with the native starch. Setback reduced in hydroxypropylated starches compared with the native starch. Enthalpy of gelatinization and percentage retrogradation reduced after hydroxypropylation and progressive reductions were observed as the MS increased among the starch derivatives. Hydroxypropylation increased enzymatic digestibility. (author)

  15. Genetic Engineering of Cereal Grains with Starch Consisting of More Than 99% Amylase

    DEFF Research Database (Denmark)

    Hebelstrup, Kim; Carciofi, Massimiliano; Blennow, Andreas

    2013-01-01

    Numerous textbooks tell us that plant starches are a mix of two starch types: amylopectin and amylose. We recently succeeded in engineering a cereal crop – a barley line – producing grain starch consisting of more than 99% amylose1. This amylose-only starch contains a high residual fraction...

  16. KINETICS OF THE HYDROXYETHYLATION OF STARCH IN ALKALINE SALT-CONTAINING AQUEOUS SLURRIES

    NARCIS (Netherlands)

    VANWARNERS, A; STAMNHUIS, EJ; BEENACKERS, AACM

    A two-phase kinetic model is presented for the base-catalyzed hydroxyethylation of potato starch using ethylene oxide at temperatures between 293 and 318 K in aqueous starch slurries containing sodium sulfate. The rate of the hydroxyethylation of starch as a function of starch anion concentration

  17. Implementing a low-starch biscuit-free diet in zoo gorillas: the impact on health.

    Science.gov (United States)

    Less, E H; Lukas, K E; Bergl, R; Ball, R; Kuhar, C W; Lavin, S R; Raghanti, M A; Wensvoort, J; Willis, M A; Dennis, P M

    2014-01-01

    In the wild, western lowland gorillas consume a diet high in fiber and low in caloric density. In contrast, many gorillas in zoos consume a diet that is high-calorie and low in fiber. Some items commonly used in captive gorilla diets contain high levels of starch and sugars, which are minimal in the natural diet of gorillas. There is a growing concern that captive gorillas may qualify as obese. Furthermore, the leading cause of death for adult male gorillas in zoos is heart disease. In humans, a diet that is high in simple carbohydrates is associated with both obesity and the incidence of heart disease. In response to these issues, we implemented a biscuit-free diet (free of biscuits and low in fruit) and measured serum biomarkers of obesity and insulin resistance pre- and post-diet change at three institutions: North Carolina Zoological Garden, Cleveland Metroparks Zoo, and Columbus Zoo and Aquarium. We also added a resistant starch supplement to gorilla diets at two of the above institutions. We anticipated that these diet changes would positively affect biomarkers of obesity and insulin resistance. Both diet manipulations led to a reduction in insulin. Resistant starch also decreased overall serum cholesterol levels. Future research will examine these health changes in a greater number of individuals to determine if the results remain consistent with these preliminary findings. © 2014 Wiley Periodicals, Inc.

  18. Directly dated starch residues document early formative maize (Zea mays L.) in tropical Ecuador.

    Science.gov (United States)

    Zarrillo, Sonia; Pearsall, Deborah M; Raymond, J Scott; Tisdale, Mary Ann; Quon, Dugane J

    2008-04-01

    The study of maize (Zea mays L.) domestication has advanced from questions of its origins to the study-and debate-of its dietary role and the timing of its dispersal from Mexico. Because the investigation of maize's spread is hampered by poor preservation of macrobotanical remains in the Neotropics, research has focused on microbotanical remains whose contexts are often dated by association, leading some to question the dates assigned. Furthermore, some scholars have argued that maize was not introduced to southwestern Ecuador until approximately 4150-3850 calendar years before the present (cal B.P.), that it was used first and foremost as a fermented beverage in ceremonial contexts, and that it was not important in everyday subsistence, challenging previous studies based on maize starch and phytoliths. To further investigate these questions, we analyzed every-day cooking vessels, food-processing implements, and sediments for starch and phytoliths from an archaeological site in southwestern Ecuador constituting a small Early Formative village. Employing a new technique to recover starch granules from charred cooking-pot residues we show that maize was present, cultivated, and consumed here in domestic contexts by at least 5300-4950 cal B.P. Directly dating the residues by accelerator mass spectrometry (AMS) radiocarbon measurement, our results represent the earliest direct dates for maize in Early Formative Ecuadorian sites and provide further support that, once domesticated approximately 9000 calendar years ago, maize spread rapidly from southwestern Mexico to northwestern South America.

  19. Lead Toxicity

    Science.gov (United States)

    ... o Do not use glazed ceramics, home remedies, cosmetics, or leaded-crystal glassware unless you know that they are lead safe. o If you live near an industry, mine, or waste site that may have contaminated ...

  20. Relational Leading

    DEFF Research Database (Denmark)

    Larsen, Mette Vinther; Rasmussen, Jørgen Gulddahl

    2015-01-01

    This first chapter presents the exploratory and curious approach to leading as relational processes – an approach that pervades the entire book. We explore leading from a perspective that emphasises the unpredictable challenges and triviality of everyday life, which we consider an interesting......, relevant and realistic way to examine leading. The chapter brings up a number of concepts and contexts as formulated by researchers within the field, and in this way seeks to construct a first understanding of relational leading....

  1. Tribology of swollen starch granule suspensions from maize and potato.

    Science.gov (United States)

    Zhang, Bin; Selway, Nichola; Shelat, Kinnari J; Dhital, Sushil; Stokes, Jason R; Gidley, Michael J

    2017-01-02

    The tribological properties of suspensions of cooked swollen starch granules are characterised for systems based on maize starch and potato starch. These systems are known as granule 'ghosts' due to the release (and removal) of polymer from their structure during cooking. Maize starch ghosts are less swollen than potato starch ghosts, resulting in a higher packing concentration and greater mechanical stability. In a soft-tribological contact, maize ghost suspensions reduce friction compared to the solvent (water), generate bell-shaped tribological profiles characteristic of particle entrainment and show a marked concentration dependence, whereas potato ghost suspensions exhibit lubrication behaviour similar to water. Microscopy analysis of the samples following tribological testing suggests that this is due to the rapid break-up of potato ghosts under the shear and rolling conditions within the tribological contact. A reduction in the small deformation moduli (associated with a weak gel structure) is also observed when the potato ghost suspensions are subjected to steady shear using parallel plate rheometry; both microscopy and particle size analysis show that this is accompanied by the partial shear-induced breakage of ghost particles. This interplay between particle microstructure and the resultant rheological and lubrication dynamics of starch ghost suspensions contributes to an enhanced mechanistic understanding of textural and other functional properties of cooked starches in food and other applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. 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.

  3. Black leaf streak disease affects starch metabolism in banana fruit.

    Science.gov (United States)

    Saraiva, Lorenzo de Amorim; Castelan, Florence Polegato; Shitakubo, Renata; Hassimotto, Neuza Mariko Aymoto; Purgatto, Eduardo; Chillet, Marc; Cordenunsi, Beatriz Rosana

    2013-06-12

    Black leaf streak disease (BLSD), also known as black sigatoka, represents the main foliar disease in Brazilian banana plantations. In addition to photosynthetic leaf area losses and yield losses, this disease causes an alteration in the pre- and postharvest behavior of the fruit. The aim of this work was to investigate the starch metabolism of fruits during fruit ripening from plants infected with BLSD by evaluating carbohydrate content (i.e., starch, soluble sugars, oligosaccharides, amylose), phenolic compound content, phytohormones, enzymatic activities (i.e., starch phosphorylases, α- and β-amylase), and starch granules. The results indicated that the starch metabolism in banana fruit ripening is affected by BLSD infection. Fruit from infested plots contained unusual amounts of soluble sugars in the green stage and smaller starch granules and showed a different pattern of superficial degradation. Enzymatic activities linked to starch degradation were also altered by the disease. Moreover, the levels of indole-acetic acid and phenolic compounds indicated an advanced fruit physiological age for fruits from infested plots.

  4. Irradiated gelatin-potato starch blends: evaluation of physicochemical properties

    International Nuclear Information System (INIS)

    Inamura, Patricia Y.; Regis, Wellington; Mastro, Nelida L.

    2015-01-01

    Macromolecular polysaccharides of large chains as starch can interlace with gelatin modifying their mechanical resistance. In this work, biodegradable bovine gelatin-potato starch blends films were developed using glycerol as plasticizer. Three formulations of gelatin/starch proportions (w/w) were used (1:0; 3:1; 1:1) and casting was the chosen method. The dried samples were then submitted to ionizing radiation coming from an electron beam (EB) accelerator with doses of 20 and 40 kGy, at room temperature, in the presence of air. Mechanical properties such as puncture strength and elongation at break were measured. Color measurements, water absorption, moisture, and film solubility were assessed. The results showed that starch addition to films based on gelatin as well as irradiation affected physical and structural properties of the films. Although the increase of starch content in the mixture led to decrease of the puncture force even in samples irradiated with the higher dose, there was a decrease of water absorption of films with the increase of the dose, and also by the higher starch content. Samples irradiated at 20 kGy presented higher moisture and film solubility. The methodology developed in this paper can be applied to other composite systems to establish the best protein:starch ratio, and the contribution of the radiation crosslinking in each specific case. (author)

  5. Irradiated gelatin-potato starch blends: evaluation of physicochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Inamura, Patricia Y.; Regis, Wellington; Mastro, Nelida L., E-mail: nlmastro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Macromolecular polysaccharides of large chains as starch can interlace with gelatin modifying their mechanical resistance. In this work, biodegradable bovine gelatin-potato starch blends films were developed using glycerol as plasticizer. Three formulations of gelatin/starch proportions (w/w) were used (1:0; 3:1; 1:1) and casting was the chosen method. The dried samples were then submitted to ionizing radiation coming from an electron beam (EB) accelerator with doses of 20 and 40 kGy, at room temperature, in the presence of air. Mechanical properties such as puncture strength and elongation at break were measured. Color measurements, water absorption, moisture, and film solubility were assessed. The results showed that starch addition to films based on gelatin as well as irradiation affected physical and structural properties of the films. Although the increase of starch content in the mixture led to decrease of the puncture force even in samples irradiated with the higher dose, there was a decrease of water absorption of films with the increase of the dose, and also by the higher starch content. Samples irradiated at 20 kGy presented higher moisture and film solubility. The methodology developed in this paper can be applied to other composite systems to establish the best protein:starch ratio, and the contribution of the radiation crosslinking in each specific case. (author)

  6. Ovary starch reserves and pistil development in avocado (Persea americana).

    Science.gov (United States)

    Alcaraz, M Librada; Hormaza, J Ignacio; Rodrigo, Javier

    2010-12-01

    In avocado, only a very small fraction of the flowers are able to set fruit. Previous work in other woody perennial plant species has shown the importance of carbohydrates accumulated in the flower in the reproductive process. Thus, in order to explore the implications of the nutritive status of the flower in the reproductive process in avocado, the starch content in the pistil has been examined in individual pollinated and non-pollinated flowers at anthesis and during the days following anthesis. Starch content in different pistilar tissues in each flower was quantified with the help of an image analysis system attached to a microscope. Flowers at anthesis were rich in highly compartmentalized starch. Although no external morphological differences could be observed among flowers, the starch content varied widely at flower opening. Starch content in the ovary is largely independent of flower size because these differences were not correlated with ovary size. Differences in the progress of starch accumulation within the ovule integuments between pollinated and non-pollinated flowers occurred concomitantly with the triggering of the progamic phase. The results suggest that starch reserves in the ovary could play a significant role in the reproductive process in avocado. Copyright © Physiologia Plantarum 2010.

  7. Atomic force microscopy of pea starch: origins of image contrast.

    Science.gov (United States)

    Ridout, Michael J; Parker, Mary L; Hedley, Cliff L; Bogracheva, Tatiana Y; Morris, Victor J

    2004-01-01

    Atomic force microscopy (AFM) has been used to image the internal structure of pea starch granules. Starch granules were encased in a nonpenetrating matrix of rapid-set Araldite. Images were obtained of the internal structure of starch exposed by cutting the face of the block and of starch in sections collected on water. These images have been obtained without staining, or either chemical or enzymatic treatment of the granule. It has been demonstrated that contrast in the AFM images is due to localized absorption of water within specific regions of the exposed fragments of the starch granules. These regions swell, becoming "softer" and higher than surrounding regions. The images obtained confirm the "blocklet model" of starch granule architecture. By using topographic, error signal and force modulation imaging modes on samples of the wild-type pea starch and the high amylose r near-isogenic mutant, it has been possible to demonstrate differing structures within granules of different origin. These architectural changes provide a basis for explaining the changed appearance and functionality of the r mutant. The growth-ring structure of the granule is suggested to arise from localized "defects" in blocklet distribution within the granule. It is proposed that these defects are partially crystalline regions devoid of amylose.

  8. Lead Test

    Science.gov (United States)

    ... to do renovation and repair projects using lead-safe work practices to avoid creating more lead dust or ... in a dangerous area? Yes. If you are working in a potentially harmful environment with exposure to lead dust or fumes: Wash ...

  9. Production of starch with antioxidative activity by baking starch with organic acids.

    Science.gov (United States)

    Miwa, Shoji; Nakamura, Megumi; Okuno, Michiko; Miyazaki, Hisako; Watanabe, Jun; Ishikawa-Takano, Yuko; Miura, Makoto; Takase, Nao; Hayakawa, Sachio; Kobayashi, Shoichi

    2011-01-01

    A starch ingredient with antioxidative activity, as measured by the DPPH method, was produced by baking corn starch with an organic acid; it has been named ANOX sugar (antioxidative sugar). The baking temperature and time were fixed at 170 °C and 60 min, and the organic acid used was selected from preliminary trials of various kinds of acid. The phytic acid ANOX sugar preparation showed the highest antioxidative activity, but the color of the preparation was almost black; we therefore selected L-tartaric acid which had the second highest antioxidative activity. The antioxidative activity of the L-tartaric acid ANOX sugar preparation was stable against temperature, light, and enzyme treatments (α-amylase and glucoamylase). However, the activity was not stable against variations in water content and pH value. The antioxidative activity of ANOX sugar was stabilized by treating with boiled water or nitrogen gas, or by pH adjustment.

  10. Physicochemical properties of cassava starch and starch-keratin prepared biofilm

    Directory of Open Access Journals (Sweden)

    Oluwasina Olugbenga Oladayo

    2016-08-01

    Full Text Available Synthetic plastics pose one of the biggest threats to the environment and a promising solution is biodegradable polymers. This study investigates the properties of biofilms prepared using starch/keratin blend with and without formaldehyde. Some starch properties in percentage are; moisture content 0.27, hydration capacity 189.66, amylopectin content 65.79 and amylose content 34.21. From the water testing results, thickness swelling, water absorption capacity and linear expansion of biofilm without formaldehyde after 10 s of soaking in water were 28.59%, 8.89% and 4.90% respectively and 65.30%, 91.33% and 46.29% respectively after 40 s. But, higher values are recorded for those biofilms made with addition of formaldehyde. Thus using water effect on the properties of the biofilms as the performance index, the research indicates that biofilms without formaldehyde had better performance than those with formaldehyde

  11. 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...

  12. Digestion site of starch from cereals and legumes in lactating dairy cows

    DEFF Research Database (Denmark)

    Larsen, M; Lund, P; Weisbjerg, M R

    2009-01-01

    The effect of grinding and rolling (i.e. processing) of cereals and legumes (i.e. source) on site of starch digestion in lactating dairy cows was tested according to a 2×2 factorial design using a dataset derived from an overall dataset compiled from four experiments conducted at our laboratory...... digestibility of starch was decreased by rolling for legumes, whereas the three other source by processing combinations did not differ. The duodenal flow of microbial starch was estimated to 276 g/d as the intercept in the regression analysis. Apparent ruminal digestibilities of starch seemed to underestimate...... true ruminal digestibility in rations with low starch intake due to a relatively higher contribution of microbial starch to total duodenal starch flow compared to rumen escape feed starch. The small intestinal and total tract digestibility of legume starch was lower compared with starch from cereals...

  13. 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.

  14. 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.

  15. Adenosine diphosphate sugar pyrophosphatase prevents glycogen biosynthesis in Escherichia coli

    Science.gov (United States)

    Moreno-Bruna, Beatriz; Baroja-Fernández, Edurne; Muñoz, Francisco José; Bastarrica-Berasategui, Ainara; Zandueta-Criado, Aitor; Rodríguez-López, Milagros; Lasa, Iñigo; Akazawa, Takashi; Pozueta-Romero, Javier

    2001-01-01

    An adenosine diphosphate sugar pyrophosphatase (ASPPase, EC 3.6.1.21) has been characterized by using Escherichia coli. This enzyme, whose activities in the cell are inversely correlated with the intracellular glycogen content and the glucose concentration in the culture medium, hydrolyzes ADP-glucose, the precursor molecule of glycogen biosynthesis. ASPPase was purified to apparent homogeneity (over 3,000-fold), and sequence analyses revealed that it is a member of the ubiquitously distributed group of nucleotide pyrophosphatases designated as “nudix” hydrolases. Insertional mutagenesis experiments leading to the inactivation of the ASPPase encoding gene, aspP, produced cells with marginally low enzymatic activities and higher glycogen content than wild-type bacteria. aspP was cloned into an expression vector and introduced into E. coli. Transformed cells were shown to contain a dramatically reduced amount of glycogen, as compared with the untransformed bacteria. No pleiotropic changes in the bacterial growth occurred in both the aspP-overexpressing and aspP-deficient strains. The overall results pinpoint the reaction catalyzed by ASPPase as a potential step of regulating glycogen biosynthesis in E. coli. PMID:11416161

  16. Chemogenomics profiling of drug targets of peptidoglycan biosynthesis pathway in Leptospira interrogans by virtual screening approaches.

    Science.gov (United States)

    Bhattacharjee, Biplab; Simon, Rose Mary; Gangadharaiah, Chaithra; Karunakar, Prashantha

    2013-06-28

    Leptospirosis is a worldwide zoonosis of global concern caused by Leptospira interrogans. The availability of ligand libraries has facilitated the search for novel drug targets using chemogenomics approaches, compared with the traditional method of drug discovery, which is time consuming and yields few leads with little intracellular information for guiding target selection. Recent subtractive genomics studies have revealed the putative drug targets in peptidoglycan biosynthesis pathways in Leptospira interrogans. Aligand library for the murD ligase enzyme in the peptidoglycan pathway has also been identified. Our approach in this research involves screening of the pre-existing ligand library of murD with related protein family members in the putative drug target assembly in the peptidoglycan biosynthesis pathway. A chemogenomics approach has been implemented here, which involves screening of known ligands of a protein family having analogous domain architecture for identification of leads for existing druggable protein family members. By means of this approach, one murC and one murF inhibitor were identified, providing a platform for developing an antileptospirosis drug targeting the peptidoglycan biosynthesis pathway. Given that the peptidoglycan biosynthesis pathway is exclusive to bacteria, the in silico identified mur ligase inhibitors are expected to be broad-spectrum Gram-negative inhibitors if synthesized and tested in in vitro and in vivo assays.

  17. Biodegradation Behaviour of Thermoplastic Starch Films Derived from Tacca leontopetaloides Starch under Controlled Composting Condition

    Science.gov (United States)

    Amin, A. M. Mohd; Sauid, S. Mohd; Hamid, K. H. Ku; Musa, M.

    2018-05-01

    The biodegradation study of thermoplastic starch (TPS) films derived from Tacca leontopetaloides starch; namely TPS/GLY, TPS/ACE and TPS/BCHR were investigated under controlled composting conditions. A manual set-up test rig in laboratory scale was built according to ISO 14855-1: 2012. The biodegradation percentage was determined by measuring the amount of CO2 evolved using titration method and validated by automatic system (Arduino UNO System) that detected the CO2 evolved. After 45 days under controlled composting condition, results indicated that TPS/GLY degraded the fastest, followed by TPS/BCHR and the TPS/ACE had the slowest degradation. The biodegradation process of TPS/GLY, TPS/ACE and TPS/BCHR also exhibited two stages with different degradation speeds. From these results, it indicated that chemical modification of the TPS films by adding acetic acid and rice husk bio-char to the thermoplastic starch can have a major impact on the biodegradation rate and final biodegradation percentage.

  18. In-vitro starch hydrolysis of chitosan incorporating whey protein and wheat starch composite gels

    Directory of Open Access Journals (Sweden)

    Natasha Yang

    2017-10-01

    Full Text Available The study examined the influence of chitosan, incorporated into whey protein and wheat starch thermo gels, on the in-vitro hydrolysis of the polysaccharide. Gels were subjected to the following external conditions containing α-amylase at constant incubation temperature of 37 °C: In the first procedure, they were immersed in phosphate buffer (0.05 M and maintained at pH 6.9 throughout the entire digestion. In the second instance, they were introduced into a salt solution, with pH and total volume adjusted at times in sync with the human gastrointestinal tract. Results indicate that low and medium molecular weight chitosan, in combination with whey protein, were effective at enhancing the protective barrier against starch degradation. Less maltose was liberated from gels containing medium molecular weight chitosan, as opposed to the low molecular weight counterpart, and results compare favorably with the outcome of the in-vitro digestion of binary whey protein and wheat starch composites. Keywords: Food science

  19. Starch-degrading enzymes from anaerobic non-clostridial bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Weber, H; Schepers, H J; Troesch, W [Fraunhofer-Institut fuer Grenzflaechen- und Bioverfahrenstechnik (IGB), Stuttgart (Germany, F.R.)

    1990-08-01

    A number of meso- and thermophilic anaerobic starch-degrading non-spore-forming bacteria have been isolated. All the isolates belonging to different genera are strictly anaerobic, as indicated by a catalase-negative reaction, and produce soluble starch-degrading enzymes. Compared to enzymes of aerobic bacteria, those of anaerobic origin mainly show low molecular mass of about 25 000 daltons. Some of the enzymes may have useful applications in the starch industry because of their unusual product pattern, yielding maltotetraose as the main hydrolysis product. (orig.).

  20. Is hydroxyethyl starch 130/0.4 safe?

    DEFF Research Database (Denmark)

    Haase, Nicolai; Perner, Anders

    2012-01-01

    ABSTRACT: It is heavily debated whether or not treatment with hydroxyethyl starch 130/0.4 contributes to the development of acute kidney failure in patients with severe sepsis. In the previous issue of Critical Care, Muller and colleagues report no association between initial resuscitation...... with hydroxyethyl starch 130/0.4 and renal impairment in a cohort of septic patients. Can we then consider hydroxyethyl starch 130/0.4 a safe intervention? The answer is no - observational data should be interpreted with caution and should mainly be used to identify risks, while safety must be assessed...

  1. 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

  2. Combinatorial biosynthesis of medicinal plant secondary metabolites

    NARCIS (Netherlands)

    Julsing, Mattijs K.; Koulman, Albert; Woerdenbag, Herman J.; Quax, Wim J.; Kayser, Oliver

    2006-01-01

    Combinatorial biosynthesis is a new tool in the generation of novel natural products and for the production of rare and expensive natural products. The basic concept is combining metabolic pathways in different organisms on a genetic level. As a consequence heterologous organisms provide precursors

  3. Peroxidase enzymes regulate collagen extracellular matrix biosynthesis.

    Science.gov (United States)

    DeNichilo, Mark O; Panagopoulos, Vasilios; Rayner, Timothy E; Borowicz, Romana A; Greenwood, John E; Evdokiou, Andreas

    2015-05-01

    Myeloperoxidase and eosinophil peroxidase are heme-containing enzymes often physically associated with fibrotic tissue and cancer in various organs, without any direct involvement in promoting fibroblast recruitment and extracellular matrix (ECM) biosynthesis at these sites. We report herein novel findings that show peroxidase enzymes possess a well-conserved profibrogenic capacity to stimulate the migration of fibroblastic cells and promote their ability to secrete collagenous proteins to generate a functional ECM both in vitro and in vivo. Mechanistic studies conducted using cultured fibroblasts show that these cells are capable of rapidly binding and internalizing both myeloperoxidase and eosinophil peroxidase. Peroxidase enzymes stimulate collagen biosynthesis at a post-translational level in a prolyl 4-hydroxylase-dependent manner that does not require ascorbic acid. This response was blocked by the irreversible myeloperoxidase inhibitor 4-amino-benzoic acid hydrazide, indicating peroxidase catalytic activity is essential for collagen biosynthesis. These results suggest that peroxidase enzymes, such as myeloperoxidase and eosinophil peroxidase, may play a fundamental role in regulating the recruitment of fibroblast and the biosynthesis of collagen ECM at sites of normal tissue repair and fibrosis, with enormous implications for many disease states where infiltrating inflammatory cells deposit peroxidases. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  4. Biosynthesis of polyhydroxyalkanotes in wildtype yeasts | Desuoky ...

    African Journals Online (AJOL)

    Biosynthesis of the biodegradable polymers polyhydroxyalkanotes (PHAs) are studied extensively in wild type and genetically modified prokaryotic cells, however the content and structure of PHA in wild type yeasts are not well documented. The purpose of this study was to screen forty yeast isolates collected from different ...

  5. Metabolic engineering for improved heterologous terpenoid biosynthesis

    NARCIS (Netherlands)

    Ryden, A.; Melillo, E.; Czepnik, M.; Kayser, O.

    Terpenoids belong to the largest class of natural compounds and are produced in all living organisms. The isoprenoid skeleton is based on assembling of C5 building blocks, but the biosynthesis of a great variety of terpenoids ranging from monoterpenoids to polyterpenoids is not fully understood

  6. Biosynthesis of silver nanoparticles synthesized by Aspergillus

    Indian Academy of Sciences (India)

    In the present study, biosynthesis of silver nanoparticles and its antioxidant, antimicrobial and cytotoxic activities were investigated. Silver nanoparticles were extracellularly synthesized using Aspergillus flavus and the formation of nanoparticles was observed after 72 h of incubation. The results recorded from colour ...

  7. Biosynthesis of furanochromones in Pimpinella monoica

    Indian Academy of Sciences (India)

    polyketide origin of their aromatic and pyrone rings while the furan ring originates via an acetate-mevalonate pathway. The plant also utilises glycine and leucine as substrate via acetate. Biotransformation of 3-H-visnagin to (6) but not to (2) was also observed. Keywords. Biosynthesis; furochromones; polyketide origin; ...

  8. Biochemical Aspects of Non-Starch Polysaccharides

    Directory of Open Access Journals (Sweden)

    Rodica Căpriţă

    2010-05-01

    Full Text Available Polysaccharides are macromolecules of monosaccharides linked by glycosidic bonds. Non-starch polysaccharides (NSP are principally non-α-glucan polysaccharides of the plant cell wall. They are a heterogeneous group of polysaccharides with varying degrees of water solubility, size, and structure. The water insoluble fiber fraction include cellulose, galactomannans, xylans, xyloglucans, and lignin, while the water-soluble fibers are the pectins, arabinogalactans, arabinoxylans, and β-(1,3(1,4-D-glucans (β-glucans. Knowledge of the chemical structure of NSP has permitted the development of enzyme technology to overcome their antinutritional effects. The physiological effects of NSP on the digestion and absorption of nutrients in human and monogastric animals have been attributed to their physicochemical properties: hydration properties, viscosity, cation exchange capacity and organic compound absorptive properties. This paper reviews and presents information on NSPs chemistry, physicochemical properties and physiological effects on the nutrient entrapment.

  9. Granular starch hydrolysis for fuel ethanol production

    Science.gov (United States)

    Wang, Ping

    Granular starch hydrolyzing enzymes (GSHE) convert starch into fermentable sugars at low temperatures (≤48°C). Use of GSHE in dry grind process can eliminate high temperature requirements during cooking and liquefaction (≥90°C). In this study, GSHE was compared with two combinations of commercial alpha-amylase and glucoamylase (DG1 and DG2, respectively). All three enzyme treatments resulted in comparable ethanol concentrations (between 14.1 to 14.2% v/v at 72 hr), ethanol conversion efficiencies and ethanol and DDGS yields. Sugar profiles for the GSHE treatment were different from DG1 and DG2 treatments, especially for glucose. During simultaneous saccharification and fermentation (SSF), the highest glucose concentration for the GSHE treatment was 7% (w/v); for DG1 and DG2 treatments, maximum glucose concentration was 19% (w/v). GSHE was used in one of the fractionation technologies (enzymatic dry grind) to improve recovery of germ and pericarp fiber prior to fermentation. The enzymatic dry grind process with GSHE was compared with the conventional dry grind process using GSHE with the same process parameters of dry solids content, pH, temperature, time, enzyme and yeast usages. Ethanol concentration (at 72 hr) of the enzymatic process was 15.5% (v/v), which was 9.2% higher than the conventional process (14.2% v/v). Distillers dried grains with solubles (DDGS) generated from the enzymatic process (9.8% db) was 66% less than conventional process (28.3% db). Three additional coproducts, germ 8.0% (db), pericarp fiber 7.7% (db) and endosperm fiber 5.2% (db) were produced. Costs and amounts of GSHE used is an important factor affecting dry grind process economics. Proteases can weaken protein matrix to aid starch release and may reduce GSHE doses. Proteases also can hydrolyze protein into free amino nitrogen (FAN), which can be used as a yeast nutrient during fermentation. Two types of proteases, exoprotease and endoprotease, were studied; protease and urea

  10. Cornmeal and starch influence the dynamic of fumonisin B, A and C production and masking in Fusarium verticillioides and F. proliferatum.

    Science.gov (United States)

    Lazzaro, Irene; Falavigna, Claudia; Galaverna, Gianni; Dall'Asta, Chiara; Battilani, Paola

    2013-08-16

    Fusarium verticillioides and F. proliferatum can infect maize ears and produce fumonisins. The fumonisin B (FB) series is the most prolifically produced, followed by fumonisin C (FC), A (FA) and P (FP); moreover hidden forms of fumonisins have been detected in maize and derivatives. There is a lack of information about which maize component may affect fumonisin pattern production. Therefore, in this work we studied the role of cornmeal and corn starch, as the sole source of nutrition, in the production dynamic of all fumonisin series, hidden forms included, in different strains of F. verticillioides and F. proliferatum incubated at 25°C for 7-45days. Both Fusarium species produced high amounts of FB, following the chemotype FB1>FB2>FB3; FC and FA were produced in lesser amounts, showing the chemotypes: FA2+FA3>FA1 and FC1>FC2+FC3>FC4, respectively; while no FP were detected. F. verticillioides was more prolific than F. proliferatum in fumonisin production (ten times more on average) in all the tested conditions. Fumonisin production was higher in cornmeal than in starch based medium in both Fusarium species; FA and FC were detected only in the former medium. An important role of amylopectin as an inducing factor for fumonisin biosynthesis was suggested, as were acid pH conditions. Fumonisin hidden forms may occur in cornmeal medium, whereas they were never found at significant levels in corn starch medium. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. A new generation starch product as excipient in pharmaceutical tablets .3. Parameters affecting controlled drug release from tablets based on high surface area retrograded pregelatinized potato starch

    NARCIS (Netherlands)

    TeWierik, GHP; Eissens, AC; ArendsScholte, AW; Bolhuis, GK

    1997-01-01

    This paper describes the general applicability of a new pregelatinized starch product in directly compressible controlled-release matrix systems. It was prepared by enzymatic degradation of potato starch followed by precipitation (retrogradation), filtration and washing with ethanol. The advantages

  12. 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...

  13. Thermoplastic starch materials prepared from rice starch; Preparacao e caracterizacao de materiais termoplasticos preparados a partir de amido de arroz

    Energy Technology Data Exchange (ETDEWEB)

    Pontes, Barbara R.B.; Curvelo, Antonio A.S., E-mail: barbarapont@gmail.co [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Inst. de Quimica

    2009-07-01

    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)

  14. A Comparative Study of the Characteristics of Cross-Linked, Oxidized and Dual-Modified Rice Starches

    OpenAIRE

    Xiao, Hua-Xi; Lin, Qin-Lu; Liu, Gao-Qiang; Yu, Feng-Xiang

    2012-01-01

    Rice starch was cross-linked with epichlorohydrin (0.3%, w/w, on a dry starch basis) and oxidized with sodium hypochlorite (2.5% w/w), respectively. Two dual-modified rice starch samples (oxidized cross-linked rice starch and cross-linked oxidized rice starch) were obtained by the oxidation of cross-linked rice starch and the cross-linking of oxidized rice starch at the same level of reagents. The physicochemical properties of native rice starch, cross-linked rice starch and oxidized rice sta...

  15. Polyvinyl alcohol/starch composite nanofibers by bubble electrospinning

    Directory of Open Access Journals (Sweden)

    Liu Zhi

    2014-01-01

    Full Text Available Bubble electrospinning exhibits profound prospect of industrialization of macro/ nano materials. Starch is the most abundant and inexpensive biopolymer. With the drawbacks of poor strength, water resistibility, thermal stability and processability of pure starch, some biodegradable synthetic polymers such as poly (lactic acid, polyvinyl alcohol were composited to electrospinning. To the best of our knowledge, composite nanofibers of polyvinyl alcohol/starch from bubble electrospinning have never been investigated. In the present study, nanofibers of polyvinyl alcohol/starch were prepared from bubble electrospinning. The processability and the morphology were affected by the weight ratio of polyvinyl alcohol and starchy. The rheological studies were in agreement with the spinnability of the electrospinning solutions.

  16. Amylase activity of a starch degrading bacteria isolated from soil ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-17

    Sep 17, 2008 ... Key words: Amylase, Bacillus, kitchen waste, starch degrading. INTRODUCTION ... several sources such as plant, animal and microbes. (Kathiresan .... Test. Response of the strain. Gram's staining. +. Shape. Bacilli. Motility. +.

  17. Glass transition of anhydrous starch by fast scanning calorimetry.

    Science.gov (United States)

    Monnier, Xavier; Maigret, Jean-Eudes; Lourdin, Denis; Saiter, Allisson

    2017-10-01

    By means of fast scanning calorimetry, the glass transition of anhydrous amorphous starch has been measured. With a scanning rate of 2000Ks -1 , thermal degradation of starch prior to the glass transition has been inhibited. To certify the glass transition measurement, structural relaxation of the glassy state has been investigated through physical aging as well as the concept of limiting fictive temperature. In both cases, characteristic enthalpy recovery peaks related to the structural relaxation of the glass have been observed. Thermal lag corrections based on the comparison of glass transition temperatures measured by means of differential and fast scanning calorimetry have been proposed. The complementary investigations give an anhydrous amorphous starch glass transition temperature of 312±7°C. This estimation correlates with previous extrapolation performed on hydrated starches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. effects of different grain starches as feed binders for

    African Journals Online (AJOL)

    users

    KEY WORDS: Grain Starches; Feed Binder, AQUA-Feed, Pelletability Water ... in their incorporation in on farm aqua feed and thus. 19 ..... International Seminar on Advanced Extrusion. Technology in Food Application, Sao Paulo. Brazil pp.

  19. Modified broken rice starch as fat substitute in sausages

    Directory of Open Access Journals (Sweden)

    Valéria Maria Limberger

    2011-09-01

    Full Text Available The demand for low-fat beef products has led the food industry to use fat substitutes such as modified starch. About 14% of broken rice is generated during processing. Nevertheless, this by-product contains high levels of starch; being therefore, great raw material for fat substitution. This study evaluated the applicability of chemically and physically modified broken rice starch as fat substitute in sausages. Extruded and phosphorylated broken rice was used in low-fat sausage formulation. All low-fat sausages presented about 55% reduction in the fat content and around 28% reduction in the total caloric value. Fat replacement with phosphorylated and extruded broken rice starch increased the texture acceptability of low-fat sausages, when compared to low-fat sausages with no modified broken rice. Results suggest that modified broken rice can be used as fat substitute in sausage formulations, yielding lower caloric value products with acceptable sensory characteristics.

  20. Preparation and characterization of polymeric nanoparticles from Gadong starch

    Science.gov (United States)

    Sisika, Regina; Ahmad, Wan Yaacob Wan; Fazry, Shazrul; Lazim, Azwan Mat

    2015-09-01

    Dioscorea hispida (Gadong tuber) was seldom used and forgotten as a food source due to their toxicity. In contrast to that, the Gadong tuber can be a source of polysaccharides which can be manipulated as an alternative source for industrial applications. This research reported on how to synthesize starch nanoparticles from Gadong tuber by using a simple acid hydrolysis process. The yield of starch nanoparticles obtained from seven days of acid hydrolysis was reduced to 13%. The X-ray diffraction measurements showed that the native Gadong starch particle is of the C-crystalline type, and that the synthesized nanoparticles showed an increase in crystallinity compared to the native particles. Transmission electron microscopy results demonstrated that the starch particle morphologies were either round or irregular shape, with diameters ranging from 96-110 nm.

  1. Preparation and characterization of polymeric nanoparticles from Gadong starch

    International Nuclear Information System (INIS)

    Sisika, Regina; Ahmad, Wan Yaacob Wan; Lazim, Azwan Mat; Fazry, Shazrul

    2015-01-01

    Dioscorea hispida (Gadong tuber) was seldom used and forgotten as a food source due to their toxicity. In contrast to that, the Gadong tuber can be a source of polysaccharides which can be manipulated as an alternative source for industrial applications. This research reported on how to synthesize starch nanoparticles from Gadong tuber by using a simple acid hydrolysis process. The yield of starch nanoparticles obtained from seven days of acid hydrolysis was reduced to 13%. The X-ray diffraction measurements showed that the native Gadong starch particle is of the C-crystalline type, and that the synthesized nanoparticles showed an increase in crystallinity compared to the native particles. Transmission electron microscopy results demonstrated that the starch particle morphologies were either round or irregular shape, with diameters ranging from 96-110 nm

  2. Development of maleated starches using an internal mixer

    International Nuclear Information System (INIS)

    Dias, Fernanda T.G.; Andrade, Cristina T.

    2009-01-01

    Novel maleated starches (MSt) were prepared by chemical modification of cornstarch with maleic anhydride (MA), using an internal mixer as a reactor. Benzoyl peroxide (BPO) was chosen as initiator. Physico-chemical parameters were determined for the process carried out at different MA contents, under the same reaction conditions. Processing was carried out at 50 deg C, 30 rpm for 8 min.Torque developed during processing was given by the digital display of the rheometer, and the total specific mechanical energy (SME) input was estimated. FTIR measurements confirmed the successful incorporation of MA into the starch backbone. In addition, WAXS diffraction analyses revealed disruption of the crystalline structure of native starch for the products. Such reactions promoted by MA reduced the crystallinity of the products. The results indicated that the MA content had a significant effect on the characteristics of the processed starch samples. (author)

  3. Amylase activity of a starch degrading bacteria isolated from soil ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-17

    Sep 17, 2008 ... was maximum in the temperature range of 50 - 70oC, whereas this temperature range was deleterious for this ... The starch nutrient medium was inoculated with a single isolated .... (1983) high temperature may inactivate the.

  4. Evaluation of Starch Biodegradable Plastics Derived from Cassava ...

    African Journals Online (AJOL)

    BSN

    2 Molecular Bio/Sciences Limited, 124 MCC Road, Calabar, Nigeria. Abstract ... cassava starch is a pure, natural biopolymer that is suitable for .... matter of fact, Ohtaki and Nakasaki (2000) reported that ... Chemistry and. Industry 31: 7 - 9.

  5. Preparation and characterization of polymeric nanoparticles from Gadong starch

    Energy Technology Data Exchange (ETDEWEB)

    Sisika, Regina; Ahmad, Wan Yaacob Wan; Lazim, Azwan Mat [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 Bangi, Selangor (Malaysia); Fazry, Shazrul [School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    Dioscorea hispida (Gadong tuber) was seldom used and forgotten as a food source due to their toxicity. In contrast to that, the Gadong tuber can be a source of polysaccharides which can be manipulated as an alternative source for industrial applications. This research reported on how to synthesize starch nanoparticles from Gadong tuber by using a simple acid hydrolysis process. The yield of starch nanoparticles obtained from seven days of acid hydrolysis was reduced to 13%. The X-ray diffraction measurements showed that the native Gadong starch particle is of the C-crystalline type, and that the synthesized nanoparticles showed an increase in crystallinity compared to the native particles. Transmission electron microscopy results demonstrated that the starch particle morphologies were either round or irregular shape, with diameters ranging from 96-110 nm.

  6. In vitro binding of puroindolines to wheat starch granules

    DEFF Research Database (Denmark)

    Sørensen, Helle Aagaard; Darlington, H.F.; Shewry, P.R.

    2001-01-01

    Puroindoline (pin) preparations made from flours of hard and soft wheats contained a mixture of pin-a, 0.19/0.53 alpha -amylase inhibitor, and purothionins. Starch granule preparations from the same cultivars were treated with proteinase to remove surface proteins and incubated with solutions...... of the pin preparations. Binding of pin-a and purothionins but not the 0.19/0.53 inhibitor was observed with no apparent differences between the behavior of the pin preparations or starch granule preparations from hard or soft types. No binding was observed when several other proteins (bovine serum albumin......, total albumins, a commercial preparation of wheat alpha -amylase inhibitors, and barley beta -amylase) were incubated with the starch granules under the same conditions, indicating that in vitro binding can be used to study specific starch granule and protein interactions....

  7. 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.

  8. Annealing properties of potato starches with different degrees of phosphorylation

    DEFF Research Database (Denmark)

    Muhrbeck, Per; Svensson, E

    1996-01-01

    Changes in the gelatinization temperature interval and gelatinization enthalpy with annealing time at 50 degrees C were followed for a number of potato starch samples, with different degrees of phosphorylation, using differential scanning calorimetry. The gelatinization temperature increased...

  9. XRD Investigation of Some Thermal Degraded Starch Based Materials

    Directory of Open Access Journals (Sweden)

    Mihai Todica

    2016-01-01

    Full Text Available The thermal degradation of some starch based materials was investigated using XRD method. The samples were obtained by thermal extrusion of mixtures of different proportions of starch, glycerol, and water. Such materials are suitable for the manufacturing of low pollutant packaging. Thermal degradation is one of the simplest ways to destroy such materials and this process is followed by structural modification of the local ordering of samples, water evaporation, crystallization, oxidation, or destruction of the chemical bonds. These modifications need to be studied in order to reduce to the minimum production of pollutant residues by burning process. XRD measurements show modification of the local ordering of the starch molecules depending on the temperature and initial composition of the samples. The molecular ordering perturbation is more pronounced in samples with low content of starch.

  10. Evaluation of grain nutritional quality and resistant starch content

    African Journals Online (AJOL)

    USER

    contained considerable levels zinc, iron, resistant starch and low levels of the undesirable phytic acid. Key Words: Iron, phytic ... processes, which in turn influence nutrient uptake ..... in diets and level of processing, daily intake can be as high ...

  11. Leading Democratically

    Science.gov (United States)

    Brookfield, Stephen

    2010-01-01

    Democracy is the most venerated of American ideas, the one for which wars are fought and people die. So most people would probably agree that leaders should be able to lead well in a democratic society. Yet, genuinely democratic leadership is a relative rarity. Leading democratically means viewing leadership as a function or process, rather than…

  12. 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...

  13. Modification of in natura starch for application in adhesives

    International Nuclear Information System (INIS)

    Lopes, Gisela K.; Andrade, Cristina T.

    2001-01-01

    Commercial modified starches used in adhesive formulations have been characterized by infrared, spectroscopy, 13 C-NMR and viscosimetry. Several reactions have been carried out with starch in natura in acid solutions and the resulting products have been compared with the commercial samples. The product obtained by acid hydrolysis at 60 deg C for 90 min was characterized as the most appropriate to be used in adhesive formulations. (author)

  14. Nanosilver: A Catalyst in Enzymatic Hydrolysis of Starch

    Directory of Open Access Journals (Sweden)

    Falkowska Marta

    2014-09-01

    Full Text Available Silver nanoparticles are widely used, because of their antimicrobial properties. In this paper, the rate of starch digestion in the presence of nanocatalyst was compared with the rate of reaction without nanosilver. The rate of enzymatic degradation of starch was found to be increased in the presence of silver nanoparticles. It is considered that α-amylase was immobilized onto the surface of nanoparticles.

  15. Development of silver and clay-starch bio-nanocomposites

    OpenAIRE

    Abreu, Ana S.; Oliveira, M.; Machado, A. V.

    2014-01-01

    Starch, among biopolymers is that had the lowest production cost, wide availability, fully biodegradability and is a renewable agriculture resource. Starch due to its sensitivity to humidity and poor mechanical properties cannot be used in many applications. For that, the dispersion of clays in this material improves their physical and mechanical properties, at very low filler loadings. On the other hand, the incorporation of silver nanoparticles into biocompatible and biod...

  16. 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

  17. 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.

  18. Substances that disrupt thyroid hormone biosynthesis (in Romanian

    Directory of Open Access Journals (Sweden)

    Pap, Andreea

    2015-06-01

    Full Text Available Endocrine disrupters are natural or synthetic chemical substances that have the possibility to alter the endocrine functions leading to serious metabolic changes especially in newborns. The accumulation and persistence over long periods of time became a priority in terms of health and environment. The mechanism of action is represented by blocking, mimicking or modifying the effects of thyroid hormones. In this review, the main purpose was to determine what effects have the endocrine disruptors on the thyroid gland, especially on the thyroid hormone biosynthesis and setting the stage involved by it. We focused on the action of perchlorates, phthalates, BPC, PDPEs, soy, isoflavones, nitrates, thiocyanates, bisphenol A and triclorsan and came to the conclusion that their intervention can result in either hyperthyroidism or hypothyroidism.

  19. Application of ultra high pressure (UHP) in starch chemistry.

    Science.gov (United States)

    Kim, Hyun-Seok; Kim, Byung-Yong; Baik, Moo-Yeol

    2012-01-01

    Ultra high pressure (UHP) processing is an attractive non-thermal technique for food treatment and preservation at room temperature, with the potential to achieve interesting functional effects. The majority of UHP process applications in food systems have focused on shelf-life extension associated with non-thermal sterilization and a reduction or increase in enzymatic activity. Only a few studies have investigated modifications of structural characteristics and/or protein functionalities. Despite the rapid expansion of UHP applications in food systems, limited information is available on the effects of UHP on the structural and physicochemical properties of starch and/or its chemical derivatives included in most processed foods as major ingredients or minor additives. Starch and its chemical derivatives are responsible for textural and physical properties of food systems, impacting their end-use quality and/or shelf-life. This article reviews UHP processes for native (unmodified) starch granules and their effects on the physicochemical properties of UHP-treated starch. Furthermore, functional roles of UHP in acid-hydrolysis, hydroxypropylation, acetylation, and cross-linking reactions of starch granules, as well as the physicochemical properties of UHP-assisted starch chemical derivatives, are discussed.

  20. 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)

  1. Effect of temperature to the properties of sago starch

    Science.gov (United States)

    Mustafa Kamal, M.; Baini, R.; Mohamaddan, S.; Selaman, O. S.; Zauzi, N. Ahmad; Rahman, M. R.; Rahman, N. Abdul; Chong, K. H.; Atan, M. F.; Samat, N. A. S. Abdul; Taib, S. N. L.; Othman, A. K.

    2017-06-01

    Recently, the importance of sago starch has increased, as it has become one of the main economically important agricultural crops to the most Southeast Asia countries. In the present work, an analysis on drying process of sago starch (Metroxylon sagu Rottb.) underwent various temperature has been made by using four empirical equations. The main goal of this analysis is to suggest the most accurate equation, in order to model and simulate the mechanical drying of sago starch. The experimental investigations were carried out in a gravity convection lab oven; and ±50g of sago starch (sample heights of 1 cm) was dried through four different temperatures, which were 50, 60, 70 and 80ºC. The effect of drying temperature on the drying kinetics, as well as various qualities attributes of sago starch, such as microstructure, colour and functional properties were investigated. The results suggested that drying temperature has significant effect on sago starch drying kinetic; therefore, drying temperature would be the basis to select drying condition. Meanwhile, it was found that the various drying temperature ranging from 50 to 80ºC affected the product quality especially in term of colour.

  2. Polycaprolactone/starch composite: Fabrication, structure, properties, and applications.

    Science.gov (United States)

    Ali Akbari Ghavimi, Soheila; Ebrahimzadeh, Mohammad H; Solati-Hashjin, Mehran; Abu Osman, Noor Azuan

    2015-07-01

    Interests in the use of biodegradable polymers as biomaterials have grown. Among the different polymeric composites currently available, the blend of starch and polycaprolactone (PCL) has received the most attention since the 1980s. Novamont is the first company that manufactured a PCL/starch (SPCL) composite under the trademark Mater-Bi®. The properties of PCL (a synthetic, hydrophobic, flexible, expensive polymer with a low degradation rate) and starch (a natural, hydrophilic, stiff, abundant polymer with a high degradation rate) blends are interesting because of the composite components have completely different structures and characteristics. PCL can adjust humidity sensitivity of starch as a biomaterial; while starch can enhance the low biodegradation rate of PCL. Thus, by appropriate blending, SPCL can overcome important limitations of both PCL and starch components and promote controllable behavior in terms of mechanical properties and degradation which make it suitable for many biomedical applications. This article reviewed the different fabrication and modification methods of the SPCL composite; different properties such as structural, physical, and chemical as well as degradation behavior; and different applications as biomaterials. © 2014 Wiley Periodicals, Inc.

  3. Wet method for measuring starch gelatinization temperature using electrical conductivity.

    Science.gov (United States)

    Morales-Sanchez, E; Figueroa, J D C; Gaytan-Martínez, M

    2009-09-01

    The objective of the present study was to develop a method for obtaining the gelatinization temperature of starches by using electrical conductivity. Native starches from corn, rice, potato, and wheat were prepared with different proportions of water and heated from room temperature to 90 degrees C, in a device especially designed for monitoring the electrical conductivity as a function of temperature. The results showed a linear trend of the electrical conductivity with the temperature until it reaches the onset gelatinization temperature. After that point, the electrical conductivity presented an increment or decrement depending on the water content in the sample and it was related to starch swelling and gelatinization phenomena. At the end gelatinization temperature, the conductivity becomes stable and linear, indicating that there are no more changes of phase. The starch gelatinization parameter, which was evaluated in the 4 types of starches using the electrical conductivity, was compared with those obtained by using differential scanning calorimeter (DSC). The onset temperature at which the electrical conductivity increased or decreased was found to be similar to that obtained by DSC. Also, the final temperature at which the electrical conductivity returned to linearity matched the end gelatinization temperature of the DSC. Further, a wet method for measuring the onset, peak, and end gelatinization temperatures as a function of temperature using the electrical conductivity curves is presented for a starch-water suspension.

  4. Towards a more versatile alpha-glucan biosynthesis in plants

    NARCIS (Netherlands)

    Kok-Jacon, G.A.; Qin, J.; Vincken, J.P.; Visser, R.G.F.

    2003-01-01

    Starch is an important storage polysaccharide in many plants. It is composed of densely packed alpha-glucans, consisting of 1,4- and 1,4,6-linked glucose residues. The starch polymers are used in many industrial applications. The biosynthetic machinery for assembling the granule has been manipulated

  5. Physical mapping of QTL for tuber yield, starch content and starch yield in tetraploid potato (Solanum tuberosum L.) by means of genome wide genotyping by sequencing and the 8.3 K SolCAP SNP array.

    Science.gov (United States)

    Schönhals, Elske Maria; Ding, Jia; Ritter, Enrique; Paulo, Maria João; Cara, Nicolás; Tacke, Ekhard; Hofferbert, Hans-Reinhard; Lübeck, Jens; Strahwald, Josef; Gebhardt, Christiane

    2017-08-22

    Tuber yield and starch content of the cultivated potato are complex traits of decisive importance for breeding improved varieties. Natural variation of tuber yield and starch content depends on the environment and on multiple, mostly unknown genetic factors. Dissection and molecular identification of the genes and their natural allelic variants controlling these complex traits will lead to the development of diagnostic DNA-based markers, by which precision and efficiency of selection can be increased (precision breeding). Three case-control populations were assembled from tetraploid potato cultivars based on maximizing the differences between high and low tuber yield (TY), starch content (TSC) and starch yield (TSY, arithmetic product of TY and TSC). The case-control populations were genotyped by restriction-site associated DNA sequencing (RADseq) and the 8.3 k SolCAP SNP genotyping array. The allele frequencies of single nucleotide polymorphisms (SNPs) were compared between cases and controls. RADseq identified, depending on data filtering criteria, between 6664 and 450 genes with one or more differential SNPs for one, two or all three traits. Differential SNPs in 275 genes were detected using the SolCAP array. A genome wide association study using the SolCAP array on an independent, unselected population identified SNPs associated with tuber starch content in 117 genes. Physical mapping of the genes containing differential or associated SNPs, and comparisons between the two genome wide genotyping methods and two different populations identified genome segments on all twelve potato chromosomes harboring one or more quantitative trait loci (QTL) for TY, TSC and TSY. Several hundred genes control tuber yield and starch content in potato. They are unequally distributed on all potato chromosomes, forming clusters between 0.5-4 Mbp width. The largest fraction of these genes had unknown function, followed by genes with putative signalling and regulatory functions. The

  6. Fructan biosynthesis in crop plants : the molecular regulation of fructan biosynthesis in chicory (Cichorium intybus L.)

    NARCIS (Netherlands)

    Arkel, van J.

    2013-01-01

    Fructan is a polymer of fructose produced by plants and microorganisms. Within the plant kingdom about 45.000 species accumulate fructan as storage carbohydrate in addition to, or instead of, starch. Fructan accumulating species are mainly found in temperate and sub-tropical regions with

  7. Modification of foxtail millet starch by combining physical, chemical and enzymatic methods.

    Science.gov (United States)

    Dey, Ashim; Sit, Nandan

    2017-02-01

    Modification of foxtail millet starch was carried out by heat moisture treatment (HT), acid hydrolysis (AH), enzymatic treatment (EH), Ultrasound treatment (UT) and their combinations. A total of 15 modified starches were prepared by combining the various methods and properties were compared with native starch. The solubilities of the starches modified by HT were found to decrease whereas for other single modifications it increased. It also increased with number of modifications applied. The swelling power decreased for all the modified starches and a decrease in swelling power was observed with increase in number of modifications. Freeze-thaw stability improved for starches modified by single physical modifications i.e. HT and UT. Decrease in viscosities was observed for the modified starches and was particularly affected by AH. The pasting temperature was found to increase for those modified starches where HT was carried out. The modified starches gave softer gels. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Structural Orders of Wheat Starch Do Not Determine the In Vitro Enzymatic Digestibility.

    Science.gov (United States)

    Wang, Shujun; Wang, Shaokang; Liu, Lu; Wang, Shuo; Copeland, Les

    2017-03-01

    In this study, we elucidated the underlying mechanisms that are responsible for the rate-limiting step for wheat starch digestion. Wheat starch samples with a degree of gelatinization (DG) ranging from 0 to 100% were prepared. As DG increased, the ordered structures of the starch were disrupted increasingly. In contrast, almost all of the increase in the rate and extent of in vitro enzymatic digestion coincided with a DG of only 6% and a minor loss of structural order. As DG increased beyond 6%, digestibility of the starch increased only slightly. We propose that the access and binding of enzymes to starch is greatly increased with only a small DG, which is followed by the simultaneous hydrolysis of crystalline and amorphous areas in gelatinized starch. In vitro enzymatic digestibility of starch was determined predominantly by enzyme binding to starch rather than the ordered structures of starch.

  9. Extraction and properties of starches from the non-traditional vegetables Yam and Taro

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Luan Alberto; Barbosa, Natalia Alves; Pereira, Joelma, E-mail: luandrade87@yahoo.com.br [Universidade Federal de Lavras (UFLA), Lavras, MG (Brazil)

    2017-04-15

    The objective of this study was to assess the chemical, physical, morphological, crystalline and thermal properties of starch from two non-traditional vegetables, yam and taro. The analyses included proximate composition percent, amylose and mineral content, water absorption capacity, absolute density, morphological properties, X-ray diffractometry, thermal properties, pasting properties and infrared spectrum. The extracted starch exhibited a high purity level with low lipid, fiber and ash contents. The electron micrographs suggested that the taro starch granules were smaller than the yam starch granules. The results for the experimental conditions used in this study indicated that the studied starches differed, especially the amylose content, granule size and crystallinity degree and the pattern of the starches. Due to the high amylose content of yam starch, this type of starch can be used for film preparation, whereas the taro starch can be used as a fat substitute due to its small granule size. (author)

  10. Trichoderma harzianum: Inhibition of mycotoxin producing fungi and toxin biosynthesis.

    Science.gov (United States)

    Braun, H; Woitsch, L; Hetzer, B; Geisen, R; Zange, B; Schmidt-Heydt, M

    2018-04-19

    A quarter of the world-wide crop is spoiled by filamentous fungi and their mycotoxins and weather extremes associated with the climate change lead to further deterioration of the situation. The ingestion of mycotoxins causes several health issues leading in the worst case to cancer in humans and animals. Common intervention strategies against mycotoxin producing fungi, such as the application of fungicides, may result in undesirable residues and in some cases to a stress induction of mycotoxin biosynthesis. Moreover, development of fungicide resistances has greatly impacted pre- and postharvest fungal diseases. Hence there is the need to develop alternative strategies to reduce fungal infestation and thus mycotoxin contamination in the food chain. Such a strategy for natural competition of important plant-pathogenic and mycotoxin producing fungi could be Trichoderma harzianum, a mycoparasitic fungus. Especially in direct comparison to certain tested fungicides, the inhibition of different tested fungal species by T. harzianum was comparable, more sustainable and in some cases more effective, too. Besides substantially reduced growth rates, a transcriptional based inhibition of mycotoxin biosynthesis in the competed Aspergillus species could be shown. Furthermore it could be clearly observed by high-resolution Scanning Electron Microscopy (SEM) that T. harzianum actively attaches to the competitor species followed by subsequent enzymatic lysis of those mycelial filaments. The analyzed isolate of T. harzianum MRI349 is not known to produce mycotoxins. In this study it could be successfully proven that T. harzianum as a biological competitor is an effective complement to the use of fungicides. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. 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.

  12. Proteome analysis of Aspergillus niger: Lactate added in starch-containing medium can increase production of the mycotoxin fumonisin B2 by modifying acetyl-CoA metabolism

    DEFF Research Database (Denmark)

    Sørensen, Louise Marie; Lametsch, Rene; Andersen, Mikael Rørdam

    2009-01-01

    containing nitrate and starch can increase fumonisin B2 production by A. niger as well as production of some other secondary metabolites. Changes in the balance of intracellular metabolites towards a higher level of carbon passing through acetyl-CoA and a high capacity to regenerate NADPH during growth...... on medium with starch and lactate were found to be the likely cause of this effect. The results lead to the hypothesis that fumonisin production by A. niger is regulated by acetyl-CoA....

  13. Use of MMT and MMT organoclay in production of starch nanocomposites; Utilizacao da MMT e da MMT organofilica na producao de nanocompositos de amido

    Energy Technology Data Exchange (ETDEWEB)

    Schlemmer, D; Sales, M J.A., [Universidade de Brasilia (LabPol/UnB), DF (Brazil). Inst. de Quimica. Lab. de Pesquisa em Polimeros; Macedo, J.L. de [Universidade de Brasilia (LabCat/UnB), DF (Brazil). Inst. de Quimica. Lab. de Catalise; Angelica, R S [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Geociencias. Lab. de Raios X

    2010-07-01

    Starch can be used to replace petrochemical plastics for short shelf life. However, starch films have poor mechanical strength and sensitivity to moisture. This can be improved through the incorporation of nanoclays, such as montmorillonite, forming nanocomposites. Nanocomposites were prepared with 1, 3, 5 and 10% of montmorillonite, using pequi oil as plasticizer. The clay was also modified with a quaternary ammonium salt. The clays were characterized by XRF, XRD, IR and TG. Results confirmed the organophilization. The nanocomposites diffractograms showed that the addition of small amounts of clay produces delaminated nanocomposites. Already the addition of larger amount of clay does not form nanocomposites, or leads to the formation of intercalated nanocomposites. (author)

  14. Structural basis for phosphatidylinositol-phosphate biosynthesis

    Science.gov (United States)

    Clarke, Oliver B.; Tomasek, David; Jorge, Carla D.; Dufrisne, Meagan Belcher; Kim, Minah; Banerjee, Surajit; Rajashankar, Kanagalaghatta R.; Shapiro, Lawrence; Hendrickson, Wayne A.; Santos, Helena; Mancia, Filippo

    2015-10-01

    Phosphatidylinositol is critical for intracellular signalling and anchoring of carbohydrates and proteins to outer cellular membranes. The defining step in phosphatidylinositol biosynthesis is catalysed by CDP-alcohol phosphotransferases, transmembrane enzymes that use CDP-diacylglycerol as donor substrate for this reaction, and either inositol in eukaryotes or inositol phosphate in prokaryotes as the acceptor alcohol. Here we report the structures of a related enzyme, the phosphatidylinositol-phosphate synthase from Renibacterium salmoninarum, with and without bound CDP-diacylglycerol to 3.6 and 2.5 Å resolution, respectively. These structures reveal the location of the acceptor site, and the molecular determinants of substrate specificity and catalysis. Functional characterization of the 40%-identical ortholog from Mycobacterium tuberculosis, a potential target for the development of novel anti-tuberculosis drugs, supports the proposed mechanism of substrate binding and catalysis. This work therefore provides a structural and functional framework to understand the mechanism of phosphatidylinositol-phosphate biosynthesis.

  15. Occurrence and biosynthesis of carotenoids in phytoplankton.

    Science.gov (United States)

    Huang, Jim Junhui; Lin, Shaoling; Xu, Wenwen; Cheung, Peter Chi Keung

    2017-09-01

    Naturally occurring carotenoids are important sources of antioxidants, anti-cancer compounds and anti-inflammatory agents and there is thus considerable market demand for their pharmaceutical applications. Carotenoids are widely distributed in marine and freshwater organisms including microalgae, phytoplankton, crustaceans and fish, as well as in terrestrial plants and birds. Recently, phytoplankton-derived carotenoids have received much attention due to their abundance, rapid rate of biosynthesis and unique composition. The carotenoids that accumulate in particular phytoplankton phyla are synthesized by specific enzymes and play unique physiological roles. This review focuses on studies related to the occurrence of carotenoids in different phytoplankton phyla and the molecular aspects of their biosynthesis. Recent biotechnological advances in the isolation and characterization of some representative carotenoid synthases in phytoplankton are also discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Leading change.

    Science.gov (United States)

    2017-02-27

    In response to feedback from nursing, midwifery and other care staff who wanted to understand better how the Leading Change, Adding Value framework applies to them, NHS England has updated its webpage to include practice examples.

  17. Comparative Transcriptome Analysis Identifies Putative Genes Involved in Steroid Biosynthesis in Euphorbia tirucalli

    Directory of Open Access Journals (Sweden)

    Weibo Qiao

    2018-01-01

    Full Text Available Phytochemical analysis of different Euphorbia tirucalli tissues revealed a contrasting tissue-specificity for the biosynthesis of euphol and β-sitosterol, which represent the two pharmaceutically active steroids in E. tirucalli. To uncover the molecular mechanism underlying this tissue-specificity for phytochemicals, a comprehensive E. tirucalli transcriptome derived from its root, stem, leaf and latex was constructed, and a total of 91,619 unigenes were generated with 51.08% being successfully annotated against the non-redundant (Nr protein database. A comparison of the transcriptome from different tissues discovered members of unigenes in the upstream steps of sterol backbone biosynthesis leading to this tissue-specific sterol biosynthesis. Among them, the putative oxidosqualene cyclase (OSC encoding genes involved in euphol synthesis were notably identified, and their expressions were significantly up-regulated in the latex. In addition, genome-wide differentially expressed genes (DEGs in the different E. tirucalli tissues were identified. The cluster analysis of those DEGs showed a unique expression pattern in the latex compared with other tissues. The DEGs identified in this study would enrich the insights of sterol biosynthesis and the regulation mechanism of this latex-specificity.

  18. Microbial biosynthesis of nontoxic gold nanoparticles

    International Nuclear Information System (INIS)

    Roy, Swarup; Das, Tapan Kumar; Maiti, Guru Prasad; Basu, Utpal

    2016-01-01

    Graphical abstract: The manuscript deals with the fungus mediated optimized biologically synthesized GNPs using Aspergillus foetidus and characterization of biosynthesized GNPs using various physico-chemical methods. The fairly stable synthesized nanoparticles have size in the range of 10–40 nm. Cytotoxicity study of biosynthesized GNPs on Human lung cancer cell line A549 showed no significant toxicity of GNPs. - Highlights: • A novel biosynthesis process of GNPs using Aspergillus foetidus. • Biosynthesized GNPs are in the range of 10–40 nm as observed from TEM. • This process of synthesis is an optimized biosynthesis process of GNPs. • Biosynthesized GNPs are noncytotoxic against A549 cell line. - Abstract: We study the extracellular biosynthesis of gold nanoparticles (GNPs) using the fungal species Aspergillus foetidus. The formation of GNPs were initially monitored by visual observation and then characterized with the help of various characterization techniques. X-ray diffraction (XRD) results revealed distinctive formation of face centered cubic crystalline GNPs. From field emission scanning electron microscopy (FESEM) the morphology of the nanoparticles were found to be roughly spherical and within the size range of 30–50 nm. The spherical and polydispersed GNPs in the range of 10–40 nm were observed by transmission electron microscopy (TEM) analysis. It was established that alkaline pH, 1 mM gold salt concentration and 75 °C temperature were the respective optimum parameter for biosynthesis of GNPs. Cell cytotoxicity of GNP was compared with that of normal gold salt solution on A549 cell. The A549 cell growth in presence of GNPs was found to be comparatively less toxic than the gold ion.

  19. Microbial biosynthesis of nontoxic gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Swarup, E-mail: swaruproy@klyuniv.ac.in [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Das, Tapan Kumar [Department of Biochemistry and Biophysics, University of Kalyani, Kalyani 741235, West Bengal (India); Maiti, Guru Prasad [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India); Department of Anesthesiology, Texas Tech University Health science Center, 3601 4th Street, Lubbock, TX 79430 (United States); Basu, Utpal [Department of Molecular Biology and Biotechnology, University of Kalyani, Kalyani 741235, West Bengal (India)

    2016-01-15

    Graphical abstract: The manuscript deals with the fungus mediated optimized biologically synthesized GNPs using Aspergillus foetidus and characterization of biosynthesized GNPs using various physico-chemical methods. The fairly stable synthesized nanoparticles have size in the range of 10–40 nm. Cytotoxicity study of biosynthesized GNPs on Human lung cancer cell line A549 showed no significant toxicity of GNPs. - Highlights: • A novel biosynthesis process of GNPs using Aspergillus foetidus. • Biosynthesized GNPs are in the range of 10–40 nm as observed from TEM. • This process of synthesis is an optimized biosynthesis process of GNPs. • Biosynthesized GNPs are noncytotoxic against A549 cell line. - Abstract: We study the extracellular biosynthesis of gold nanoparticles (GNPs) using the fungal species Aspergillus foetidus. The formation of GNPs were initially monitored by visual observation and then characterized with the help of various characterization techniques. X-ray diffraction (XRD) results revealed distinctive formation of face centered cubic crystalline GNPs. From field emission scanning electron microscopy (FESEM) the morphology of the nanoparticles were found to be roughly spherical and within the size range of 30–50 nm. The spherical and polydispersed GNPs in the range of 10–40 nm were observed by transmission electron microscopy (TEM) analysis. It was established that alkaline pH, 1 mM gold salt concentration and 75 °C temperature were the respective optimum parameter for biosynthesis of GNPs. Cell cytotoxicity of GNP was compared with that of normal gold salt solution on A549 cell. The A549 cell growth in presence of GNPs was found to be comparatively less toxic than the gold ion.

  20. GNC and CGA1 Modulate Chlorophyll Biosynthesis and Glutamate Synthase (GLU1/Fd-GOGAT) Expression in Arabidopsis

    Science.gov (United States)

    Hudson, Darryl; Guevara, David; Yaish, Mahmoud W.; Hannam, Carol; Long, Nykoll; Clarke, Joseph D.; Bi, Yong-Mei; Rothstein, Steven J.

    2011-01-01

    Chloroplast development is an important determinant of plant productivity and is controlled by environmental factors including amounts of light and nitrogen as well as internal phytohormones including cytokinins and gibberellins (GA). The paralog GATA transcription factors GNC and CGA1/GNL up-regulated by light, nitrogen and cytokinin while also being repressed by GA signaling. Modifying the expression of these genes has previously been shown to influence chlorophyll content in Arabidopsis while also altering aspects of germination, elongation growth and flowering time. In this work, we also use transgenic lines to demonstrate that GNC and CGA1 exhibit a partially redundant control over chlorophyll biosynthesis. We provide novel evidence that GNC and CGA1 influence both chloroplast number and leaf starch in proportion to their transcript level. GNC and CGA1 were found to modify the expression of chloroplast localized GLUTAMATE SYNTHASE (GLU1/Fd-GOGAT), which is the primary factor controlling nitrogen assimilation in green tissue. Altering GNC and CGA1 expression was also found to modulate the expression of important chlorophyll biosynthesis genes (GUN4, HEMA1, PORB, and PORC). As previously demonstrated, the CGA1 transgenic plants demonstrated significantly altered timing to a number of developmental events including germination, leaf production, flowering time and senescence. In contrast, the GNC transgenic lines we analyzed maintain relatively normal growth phenotypes outside of differences in chloroplast development. Despite some evidence for partial divergence, results indicate that regulation of both GNC and CGA1 by light, nitrogen, cytokinin, and GA acts to modulate nitrogen assimilation, chloroplast development and starch production. Understanding the mechanisms controlling these processes is important for agricultural biotechnology. PMID:22102866

  1. Evaluation of the types of starch for preparation of LDPE/starch blends

    Directory of Open Access Journals (Sweden)

    Glória Maria Vinhas

    2007-05-01

    Full Text Available This study evaluated in relation the growth, and the amylolytic activity of mixed and isolated cultures of Phanerochaete chrysosporium and Talaromyces wortmanni on different types of starch. The thermal and mechanical properties in polyethylene/starch blends (proportion: 80/20 (w/w before and after inoculation of the mixed cultures were evaluated. The regular starch Amidex 3 and the modified starch Fox5901 stood out in relation to the cellular growth and production of the amylase enzyme. In spite of the short time that the blends were exposed to the fungi, the microorganisms promoted physical and chemical changes in the structure of the blend, modifying its thermal and mechanical properties. The alteration of the degree of crystallinity and mechanical properties of the blends could be indications of the modification caused by the biodegradation process.Nesse trabalho foi realizado um estudo sobre diferentes tipos de amido quanto ao crescimento, e a atividade amilolítica de culturas mistas e isoladas dos fungos Phanerochaete chrysosporium e Talaromyces wortmannii. Avaliaram-se também as propriedades térmicas e mecânicas das blendas de polietileno/amido anfótero (na proporção 80/20 (m/m antes e apos a inoculação das culturas mistas desses fungos.O amido regular Amidex 3 e o amido modificado Fox5901 foram os que se destacaram quanto ao crescimento celular e produção da enzima amilase. Apesar do pouco tempo de exposição dos filmes com os fungos, pode-se concluir que os microrganismos promovem mudanças físicas e químicas na estrutura da blenda, modificando suas propriedades térmicas e mecânicas. A alteração do grau de cristalinidade e das propriedades mecânicas das blendas podem ser indícios da modificação provocada pelo processo de biodegradação.

  2. Effect of low-doses gamma radiation on physico-chemical properties of cereal starches

    International Nuclear Information System (INIS)

    Gambus, H.; Juszczak, L.; Achremowicz, B.

    1995-01-01

    Wheat starch of Emika variety was treated with 3 and 5 kGy doses of gamma radiation, rye starch of Dankowskie Zlote variety and triticale starch of Dagro variety - with 3 kGy doses. Radiation of this starch caused an increase of reduction ability and water solubility at 60 and 80 o C. However with the increased radiation doses a significant decrease of maximum viscosity and of the viscosity of starch pastes being cooled to 50% was observed. Mild radiopolimerization also decreased the degree of retrogradation of wheat and rye starch pastes stored at above 0 o C. (author)

  3. Continuous hydrogen production from starch by fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Keigo; Tanisho, Shigeharu [Yokohama National Univ. (Japan)

    2010-07-01

    This study was investigated the effect of hydraulic retention time (HRT) on hydrogen production rate, hydrogen yield and the production rate of volatile fatty acid. The experiment was performed in a continuous stirred tank reactor (CSTR) with a working volume of 1 L by using a Clostridium sp. The temperature of the CSTR was regulated 37 C. The pH was controlled 6.0 by the addition of 3 M of NaOH solution. Starch was used as the carbon source with the concentration of 30 g L{sup -1}. Hydrogen production rate increased from 0.9 L-H{sub 2} L-culture{sup -1} h{sup -1} to 3.2 L-H{sub 2} L-culture{sup -1} h{sup -1} along with the decrease of HRT from 9 h to 1.5 h. Hydrogen yield decreased at low HRT. The major volatile fatty acids are acetic acid, butyric acid and lactic acid. The production rates of acetic acid and butyric acid increased along with the decrease of HRT. On the other hand, the rate of lactic acid was low at high HRT while it increased at HRT 1.5 h. The increase of the production rate of lactic acid suggested one of the reasons that hydrogen yield decreased. (orig.)

  4. Starch and fibre intake and glucose postprandial response of dogs

    Directory of Open Access Journals (Sweden)

    Mariana Monti

    2016-02-01

    Full Text Available ABSTRACT: Fibre has been studied to reduce the postprandial glucose response of dogs, but the results are inconsistent. Starch intake, however, was not properly considered in the published studies. The effects of starch and fibre intake on the postprandial glucose response were studied in non-obese adult dogs. Cellulose (CEL, carboxymethylcellulose (CMC, pea fibre (PE and sugarcane fibre (SCF were combined to form six diets with starch contents ranging from 33% to 42%: SCF+CEL and PE+CEL diets, both with high insoluble fibre (IF=22% and low soluble fibre (SF=2.5% content; SCF+CMC and PE+CMC diets with high SF (SF=4.5%; IF=19% content; and CMC and CEL diets with low dietary fibre (14% content. The diets were fed in two amounts, providing an intake of 9.5g or 12.5g of starch (kg0.75-1 day-1, totaling 12 treatments. Each diet was fed to six dogs conditioned to consume all of the daily food in 10min. Their plasma glucose levels were measured before and during 480min after food intake. Results of fibre and starch intake and their interactions were compared by repeated measures ANOVA and the Tukey test (P0.05. High-dose starch intake, however, induced a higher glycaemia at 180 and 240min after the meal and a greater maximal glycaemia and greater area under the glucose curve (P<0.05. A range in insoluble and soluble fibre intake does not change postprandial glucose response, and the amount of starch intake is a main factor for the postprandial glucose response of healthy non-obese dogs.

  5. 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.

  6. 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.

  7. 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

  8. Influence of starch origin on rheological properties of concentrated aqueous solutions

    Directory of Open Access Journals (Sweden)

    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.

  9. Ecotoxicology: Lead

    Science.gov (United States)

    Scheuhammer, A.M.; Beyer, W.N.; Schmitt, C.J.; Jorgensen, Sven Erik; Fath, Brian D.

    2008-01-01

    Lead (Pb) is a naturally occurring metallic element; trace concentrations are found in all environmental media and in all living things. However, certain human activities, especially base metal mining and smelting; combustion of leaded gasoline; the use of Pb in hunting, target shooting, and recreational angling; the use of Pb-based paints; and the uncontrolled disposal of Pb-containing products such as old vehicle batteries and electronic devices have resulted in increased environmental levels of Pb, and have created risks for Pb exposure and toxicity in invertebrates, fish, and wildlife in some ecosystems.

  10. Synthesis and Characterization of Starch-based Aqueous Polymer Isocyanate Wood Adhesive

    Directory of Open Access Journals (Sweden)

    Shu-min Wang

    2015-09-01

    Full Text Available Modified starch was prepared in this work by acid-thinning and oxidizing corn starch with ammonium persulfate. Also, starch-based aqueous polymer isocyanate (API wood adhesive was prepared. The effect of the added amount of modified starch, styrene butadiene rubber (SBR, polymeric diphenylmethane diisocyanate (P-MDI, and the mass concentration of polyvinyl alcohol (PVOH on the bonding strength of starch-based API adhesives were determined by orthogonal testing. The starch-based API adhesive performance was found to be the best when the addition of modified starch (mass concentration 35% was 45 g, the amount of SBR was 3%, the PVOH mass concentration was 10%, and the amount of P-MDI was 18%. The compression shearing of glulam produced by starch-based API adhesive reached bonding performance indicators of I type adhesive. A scanning electron microscope (SEM was used to analyze the changes in micro-morphology of the starch surface during each stage. Fourier transform infrared spectroscopy (FT-IR was used to study the changes in absorption peaks and functional groups from starch to starch-based API adhesives. The results showed that during starch-based API adhesive synthesis, corn starch surface was differently changed and it gradually reacted with other materials.

  11. Resistant Starch Contents of Native and Heat-Moisture Treated Jackfruit Seed Starch

    Directory of Open Access Journals (Sweden)

    Ornanong S. Kittipongpatana

    2015-01-01

    Full Text Available Native jackfruit seed starch (JFS contains 30% w/w type II resistant starch (RS2 and can potentially be developed as a new commercial source of RS for food and pharmaceutical application. Heat-moisture treatment (HMT was explored as a mean to increase RS content of native JFS. The effect of the conditions was tested at varied moisture contents (MC, temperatures, and times. Moisture levels of 20–25%, together with temperatures 80–110°C, generally resulted in increases of RS amount. The highest amount of RS (52.2% was achieved under treatment conditions of 25% MC and 80°C, for 16 h (JF-25-80-16. FT-IR peak ratio at 1047/1022 cm−1 suggested increases in ordered structure in several HMT-JFS samples with increased RS. SEM showed no significant change in the granule appearance, except at high moisture/temperature treatment. XRD revealed no significant change in peaks intensities, suggesting the crystallinity within the granule was mostly retained. DSC showed increases in Tg and, in most cases, ΔT, as the MC was increased in the samples. Slight but significant decreases in ΔH were observed in samples with low RS, indicating that a combination of high moisture and temperature might cause partial gelatinization. HMT-JFS with higher RS exhibited less swelling, while the solubility remained mostly unchanged.

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

    International Nuclear Information System (INIS)

    Cieśla, Krystyna; Watzeels, Nick; Rahier, Hubert

    2014-01-01

    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. The starch was irradiated with a dose of 30 kGy. The films were prepared by casting from solutions with addition of 0, 20 and 30 wt% of glycerol. Two endotherms attributed to glass transitions were observed in water or glycerol plasticised samples, the first one shifting to higher temperature after irradiation. A similar shift was observed after irradiation of films prepared from starch–sodium laurate and starch–sodium palmitate systems, while a decrease in glass transition temperature was observed in the case of starch–cetyltrimethylammonium bromide films. Small differences in the content of the volatile fraction reached after the appropriate conditioning had no impact on the direction of temperature shift of Tg observed after irradiation. - Highlights: • The films were prepared basing starch, surfactant and glycerol. • Two glass transitions were observed showing an existence of two phase system. • The first Tg of the starch–CTAB films shifts after irradiation to lower temperature. • In all the other cases it shifts after irradiation to higher temperature. • Differences in volatile fractions content are not important for the temperature shift

  13. 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.

  14. 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

  15. 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

  16. Leading men

    DEFF Research Database (Denmark)

    Bekker-Nielsen, Tønnes

    2016-01-01

    Through a systematic comparison of c. 50 careers leading to the koinarchate or high priesthood of Asia, Bithynia, Galatia, Lycia, Macedonia and coastal Pontus, as described in funeral or honorary inscriptions of individual koinarchs, it is possible to identify common denominators but also disting...

  17. Fatty Acid Biosynthesis Pathways in Methylomicrobium buryatense 5G(B1).

    Science.gov (United States)

    Demidenko, Aleksandr; Akberdin, Ilya R; Allemann, Marco; Allen, Eric E; Kalyuzhnaya, Marina G

    2016-01-01

    Methane utilization by methanotrophic bacteria is an attractive application for biotechnological conversion of natural or biogas into high-added-value products. Haloalcaliphilic methanotrophic bacteria belonging to the genus Methylomicrobium are among the most promising strains for methane-based biotechnology, providing easy and inexpensive cultivation, rapid growth, and the availability of established genetic tools. A number of methane bioconversions using these microbial cultures have been discussed, including the derivation of biodiesel, alkanes, and OMEGA-3 supplements. These compounds are derived from bacterial fatty acid pools. Here, we investigate fatty acid biosynthesis in Methylomicrobium buryatense 5G(B1) . Most of the genes homologous to typical Type II fatty acid biosynthesis pathways could be annotated by bioinformatics analyses, with the exception of fatty acid transport and regulatory elements. Different approaches for improving fatty acid accumulation were investigated. These studies indicated that both fatty acid degradation and acetyl- and malonyl-CoA levels are bottlenecks for higher level fatty acid production. The best strain generated in this study synthesizes 111 ± 2 mg/gDCW of extractable fatty acids, which is ~20% more than the original strain. A candidate gene for fatty acid biosynthesis regulation, farE , was identified and studied. Its deletion resulted in drastic changes to the fatty acid profile, leading to an increased pool of C18-fatty acid methyl ester. The FarE-regulon was further investigated by RNA-seq analysis of gene expression in farE -knockout mutants and farE -overexpressing strains. These gene profiles highlighted a novel set of enzymes and regulators involved in fatty acid biosynthesis. The gene expression and fatty acid profiles of the different farE -strains support the hypothesis that metabolic fluxes upstream of fatty acid biosynthesis restrict fatty acid production in the methanotroph.

  18. Microbial production of hydrogen from starch-manufacturing wastes

    Energy Technology Data Exchange (ETDEWEB)

    Yokoi, H.; Maki, R.; Hirose, J.; Hayashi, S. [Miyazaki Univ. (Japan). Dept. of Applied Chemistry

    2002-05-01

    Effective hydrogen production from starch-manufacturing wastes by microorganisms was investigated. Continuous hydrogen production in high yield of 2.7 mol H{sub 2} mol{sup -1} glucose was attained by a mixed culture of Clostridium butyricum and Enterobacter aerogenes HO-39 in the starch waste medium consisting of sweet potato starch residue as a carbon source and corn steep liquor as a nitrogen source in a repeated batch culture. Rhodobacter sp. M-19 could produce hydrogen from the supernatant of the culture broth obtained in the repeated batch culture of C. butyricum and E. aerogenes HO-39. Hydrogen yield of 4.5 mol H{sub 2} mol{sup -1} glucose was obtained by culturing Rhodobacter sp. M-19 in the supernatant supplemented with 20{mu}gl{sup -1} Na{sub 2}MoO{sub 4} 2H{sub 2}O and 10mgl{sup -1} EDTA in a repeated batch culture with pH control at 7.5. Therefore, continuous hydrogen production with total hydrogen yield of 7.2 mol H{sub 2} mol{sup -1} glucose from the starch remaining in the starch residue was attained by the repeated batch culture with C. butyricum and E. aerogenes HO-39 and by the successive repeated batch culture with Rhodobacter sp. M-19. (Author)

  19. Cassava starch as a stabilizer of soy-based beverages.

    Science.gov (United States)

    Drunkler, Northon Lee; Leite, Rodrigo Santos; Mandarino, José Marcos Gontijo; Ida, Elza Iouko; Demiate, Ivo Mottin

    2012-10-01

    Soy-based beverages are presented as healthy food alternatives for human nutrition. Cassava (Manihot esculenta, Crantz) starch is relatively inexpensive, widely available in Brazil and is broadly used by the food industry due to its desired properties that result from pasting. The objective of this study was to develop soy-based beverages with good sensory quality using native cassava starch as a stabilizer and maintaining the nutritional value that makes this product a functional food. The developed formulations featured a range of cassava starch and soybean extract concentrations, which were tested in a 2² experimental design with three central points. The results of sensory analysis showed that the studied variables (cassava starch and soybean extract concentrations) did not have a significant effect with respect to a 5% probability level. When considering the apparent viscosity, on the other hand, the variables had a significant effect: the increase in soybean extract and cassava starch concentrations caused an increase in the viscosity of the final product. The profile of isoflavones in the tested formulations was similar to the profiles reported in other papers, with a predominance of the conjugated glycosides over the aglycone forms.

  20. Understanding shape and morphology of unusual tubular starch nanocrystals.

    Science.gov (United States)

    Gong, Bei; Liu, Wenxia; Tan, Hua; Yu, Dehai; Song, Zhaoping; Lucia, Lucian A

    2016-10-20

    Starch nanocrystals (SNC) are aptly described as the insoluble degradation byproducts of starch granules that purportedly display morphologies that are platelet-like, round, square, and oval-like. In this work, we reported the preparation of SNC with unprecedented tubular structures through sulfuric acid hydrolysis of normal maize starch, subsequent exposure to ammonia and relaxation at 4°C. High-resolution transmission electron microscopy observation clearly proved that the SNCs possess tubular nanostructures with polygonal cross-section. After further reviewing the transformations of SNC by acid hydrolysis, ammonia treatment, and curing time at 4°C, a mechanism for T-SNC formation is suggested. It is conjectured that T-SNC gradually self-assembles by combination of smaller platelet-like/square nanocrystals likely loosely aggregated by starch molecular chains from residual amorphous regions. This work paves the way for the pursuit of new approaches for the preparation of starch-based nanomaterials possessing unique morphologies. Copyright © 2016 Elsevier Ltd. All rights reserved.