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Sample records for callunae starch phosphorylase

  1. Immobilization of starch phosphorylase from seeds of Indian millet ...

    African Journals Online (AJOL)

    SERVER

    2007-12-03

    Dec 3, 2007 ... Starch phosphorylase has been isolated from the seeds of millet (Pennisetum typhoides) variety KB560 and partially .... After storage for 5 h, it was centrifuged at 15000 x g for 20 ..... The property of reuse up to so many times.

  2. 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...

  3. Cisgenic inhibition of the potato cold induced phosphorylase L gene ...

    African Journals Online (AJOL)

    transgenic line M4), implying that silencing of starch phosphorylase L gene reduced starch breakdown during cold storage conditions. Key words: Cold sweetening, potato (Solanum tuberosum L.), RNA interference, starch phosphorylase L. gene, ...

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

    Science.gov (United States)

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

    2016-03-01

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

  5. 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

  6. MAO-A inhibitory activity of quercetin from Calluna vulgaris (L.) Hull

    DEFF Research Database (Denmark)

    Saaby, Lasse; Rasmussen, Hasse Bonde; Jäger, Anna Katharina

    2009-01-01

    AIM OF THE STUDY: This study investigated MAO-A inhibitory activity of methanol extract of Calluna vulgaris (L.) Hull., which traditionally has been used as a nerve calming remedy. MATERIALS AND METHODS: A methanolic extract of Calluna vulgaris was partitioned against heptane, ethyl acetate...

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

    Science.gov (United States)

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

    2014-07-31

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

  8. Stress responses of Calluna vulgaris to reduced and oxidised N applied under 'real world conditions'

    International Nuclear Information System (INIS)

    Sheppard, Lucy J.; Leith, Ian D.; Crossley, A.; Van Dijk, N.; Fowler, D.; Sutton, M.A.; Woods, C.

    2008-01-01

    Effects and implications of reduced and oxidised N, applied under 'real world' conditions, since May 2002, are reported for Calluna growing on an ombrotrophic bog. Ammonia has been released from a 10 m line source generating monthly concentrations of 180-6 μg m -3 , while ammonium chloride and sodium nitrate are applied in rainwater at nitrate and ammonium concentrations below 4 mM and providing up to 56 kg N ha -1 year -1 above a background deposition of 10 kg N ha -1 year -1 . Ammonia concentrations, >8 μg m -3 have significantly enhanced foliar N concentrations, increased sensitivity to drought, frost and winter desiccation, spring frost damage and increased the incidence of pathogen outbreaks. The mature Calluna bushes nearest the NH 3 source have turned bleached and moribund. By comparison the Calluna receiving reduced and oxidised N in rain has shown no significant visible or stress related effects with no significant increase in N status. - Exposure to NH 3 reduces stress resistance and increases visible damage in mature Calluna

  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. 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.

  11. 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.

  12. Muscle phosphorylase kinase deficiency

    DEFF Research Database (Denmark)

    Preisler, N; Orngreen, M C; Echaniz-Laguna, A

    2012-01-01

    To examine metabolism during exercise in 2 patients with muscle phosphorylase kinase (PHK) deficiency and to further define the phenotype of this rare glycogen storage disease (GSD).......To examine metabolism during exercise in 2 patients with muscle phosphorylase kinase (PHK) deficiency and to further define the phenotype of this rare glycogen storage disease (GSD)....

  13. Effects of Planting of Calluna Vulgaris for Stable Snow Accumulation in Winter

    Science.gov (United States)

    Ibuki, R.; Harada, K.

    2017-12-01

    Recent year climate of the winter season is changing and the period of snow accumulation is reduced compared with before. It affects the management of the ski resort. Snowfall had occurred in December 2016, but the snow accumulated after January 2017 at the ski resort located in the Pacific Ocean side of the Northeast region of Japan. This situation is thought to be originated from two reasons, one is snow thawing, another is to be blown away by the strong monsoon wind. We are considering utilizing planting to stabilize snow accumulation. Currently building rock gardens with shrubs, mainly Calluna Vulgaris in the ski resort for attracting customers in the summer. These are difficult to raise in the lowlands of Japan because they are too hot, but because of their good growth in relatively low-temperature highlands, it is rare for local residents to appreciate the value of these. In addition, it is excellent in low temperature resistance, and it will not die even under the snow. We investigated the pressure resistance performance due to snowfall and the appropriateness of growth under the weather conditions of the area. Regarding Calluna Vulgaris, Firefly, the plants were not damaged even under snow more than 1 m. In addition, three years have passed since planting, relatively good growth is shown, and the stock has been growing every year. Based on these results, we plan to stabilize the snow accumulation by carrying out planting of Calluna vulgaris inside the slope. The growth of the Calluna species is gentle and the tree height grows only about 50 cm even if 15 years have passed since planting. Therefore, it is considered that the plant body is hard to put out their head on the snow surface during the ski season. Next season will monitor the snow accumulation around the planting area through the snow season.

  14. 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

  15. Two purine nucleoside phosphorylases in Bacillus subtilis. Purification and some properties of the adenosine-specific phosphorylase

    DEFF Research Database (Denmark)

    Jensen, Kaj Frank

    1978-01-01

    Two purine nucleoside phosphorylases (purine-nucleoside:orthophosphate ribosyltransferase, EC 2.4.2.1) were purified from vegetative Bacillus subtilis cells. One enzyme, inosine-guanosine phosphorylase, showed great similarity to the homologous enzyme of Bacillus cereus. It appeared...

  16. Mechanism of activation of glycogen phosphorylase by fructose in the liver. Stimulation of phosphorylase kinase related to the consumption of adenosine triphosphate.

    Science.gov (United States)

    Van de Werve, G; Hers, H G

    1979-01-15

    1. A dose-dependent activation of phosphorylase and consumption of ATP was observed in isolated hepatocytes incubated in the presence of fructose; histone kinase and phosphorylase kinase activities were unchanged at doses of this sugar that were fully effective on phosphorylase. The activation of phosphorylase by fructose was also observed in cells incubated in a Ca2+-free medium as well as in the livers of rats in vivo. 2. In a liver high-speed supernatant, fructose, tagatose and sorbose stimulated the activity of phosphorylase kinase; this effect was dependent on the presence of K+ ions, which are required for the activity of fructokinase; it was accompanied by the transformation of ATP into ADP. In the presence of hexokinase, glucose also stimulated phosphorylase kinase, both in an Na+ or a K+ medium. 3. The activities of partially purified muscle or liver phosphorylase kinase were unchanged in the presence of fructose. 4. Some properties of liver phosphorylase kinase are described, including a high molecular weight and an inhibition at ATP/Mg ratios above 0.5, as well as an effect of ATP concentration on the hysteretic behaviour of this enzyme. 5. The effect of fructose on the activation of phosphorylase is discussed in relation to the comsumption of ATP.

  17. Efficient chemoenzymatic oligosaccharide synthesis by reverse phosphorolysis using cellobiose phosphorylase and cellodextrin phosphorylase from Clostridium thermocellum

    DEFF Research Database (Denmark)

    Nakai, Hiroyuki; Abou Hachem, Maher; Petersen, Bent O.

    2010-01-01

    Inverting cellobiose phosphorylase (CtCBP) and cellodextrin phosphorylase (CtCDP) from Clostridium thermocellum ATCC27405 of glycoside hydrolase family 94 catalysed reverse phosphorolysis to produce cellobiose and cellodextrins in 57% and 48% yield from α-d-glucose 1-phosphate as donor with glucose...

  18. The Crystal Structure of Streptococcus pyogenes Uridine Phosphorylase Reveals a Distinct Subfamily of Nucleoside Phosphorylases

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Timothy H.; Christoffersen, S.; Allan, Paula W.; Parker, William B.; Piskur, Jure; Serra, I.; Terreni, M.; Ealick, Steven E. (Cornell); (Pavia); (Lund); (Southern Research)

    2011-09-20

    Uridine phosphorylase (UP), a key enzyme in the pyrimidine salvage pathway, catalyzes the reversible phosphorolysis of uridine or 2'-deoxyuridine to uracil and ribose 1-phosphate or 2'-deoxyribose 1-phosphate. This enzyme belongs to the nucleoside phosphorylase I superfamily whose members show diverse specificity for nucleoside substrates. Phylogenetic analysis shows Streptococcus pyogenes uridine phosphorylase (SpUP) is found in a distinct branch of the pyrimidine subfamily of nucleoside phosphorylases. To further characterize SpUP, we determined the crystal structure in complex with the products, ribose 1-phosphate and uracil, at 1.8 {angstrom} resolution. Like Escherichia coli UP (EcUP), the biological unit of SpUP is a hexamer with an ?/? monomeric fold. A novel feature of the active site is the presence of His169, which structurally aligns with Arg168 of the EcUP structure. A second active site residue, Lys162, is not present in previously determined UP structures and interacts with O2 of uracil. Biochemical studies of wild-type SpUP showed that its substrate specificity is similar to that of EcUP, while EcUP is {approx}7-fold more efficient than SpUP. Biochemical studies of SpUP mutants showed that mutations of His169 reduced activity, while mutation of Lys162 abolished all activity, suggesting that the negative charge in the transition state resides mostly on uracil O2. This is in contrast to EcUP for which transition state stabilization occurs mostly at O4.

  19. Studies on allosteric phenomena in glycogen phosphorylase b.

    Science.gov (United States)

    Madsen, N B; Avramovic-Zikic, O; Lue, P F; Honikel, K O

    1976-03-26

    This article attempts to trace, from a personal point of view, the history of discoveries of allosteric phenomena in phosphorylase b and the later development of systematic attempts to fit the data into comprehensive theoretical models. Work from our own laboratory is emphasized, but we try to integrate this into the results from other investigators and show their contributions to our ideas and experiments. Finally, some recent unpublished data is presented together with some conclusions and predictions from a new hypothesis. The discoveries by Carl and Gerty Cori of the activation of phosphorylase by AMP, the inhibition of glucose and the enzymatic interconversion of two forms fo the enzyme with different control properties helped lay the foundations of our present understanding of allosteric mechanisms. The later discovery of the oligomeric nature of phosphorylase and its relationship to AMP binding served as a basis for many years of research into the structure-function relationships of phosphorylase and other enzymes. Data showing that AMP lowers the entropy of activation is discussed with respect to the role of the nucleotide and its binding close to the active site. The discovery of the control of phosphorylase b by common metabolites and the impetus this gave to the intensive kinetic studies of the last ten years, wherein fitting to theoretical models has been a common feature, is reviewed.

  20. [Activities and properties of phosphorylases of turbellariae Phagocata sibirica and cestodes Bothriocephalus scorpii].

    Science.gov (United States)

    Burenina, E A

    2007-01-01

    Activities and properties of phosphorylases of cytosol and mitochondrial fractions are studied in free-living turbellaria Phagocata sibirica and cestodes Bothriocephalus scorpii. The phosphorylase activities in P. sibirica and B. scorpii differ significantly both in form and the total activity of this enzyme. Dependence of the phosphorylase reaction rate on substrate concentration is studied. The high activity of phosphorylase as compared with that of hexokinase suggests glycogen to be the main energy source of the studied flatworms. Effects of various effectors on activities of cytosol and mitochondrial phosphorylases are studied.

  1. Rational engineering of Lactobacillus acidophilus NCFM maltose phosphorylase into either trehalose or kojibiose dual specificity phosphorylase

    DEFF Research Database (Denmark)

    Nakai, Hiroyuki; Petersen, B.O.; Westphal, Y.

    2010-01-01

    . LaMP has about 35 and 26% amino acid sequence identity with GH65 trehalose phosphorylase (TP) and kojibiose phosphorylase (KP) from Thermoanaerobacter brockii ATCC35047. The structure of L. brevis MP and multiple sequence alignment identified (alpha/alpha)(6)-barrel loop 3 that forms the rim...... group of the glucose moiety at subsite +1, by corresponding segments from Ser426-Ala431 in TP and Thr419-Phe427 in KP, thus conferred LaMP with phosphorolytic activity towards trehalose and kojibiose, respectively. Two different loop 3 LaMP variants catalysed the formation of trehalose and kojibiose...

  2. Recent development of phosphorylases possessing large potential for oligosaccharide synthesis

    DEFF Research Database (Denmark)

    Nakai, Hiroyuki; Kitaoka, Motomitsu; Svensson, Birte

    2013-01-01

    Phosphorylases are one group of carbohydrate active enzymes involved in the cleavage and formation of glycosidic linkages together with glycoside hydrolases and sugar nucleotide-dependent glycosyltransferases. Noticeably, the catalyzed phosphorolysis is reversible, making phosphorylases suitable...

  3. Precision Synthesis of Functional Polysaccharide Materials by Phosphorylase-Catalyzed Enzymatic Reactions

    Directory of Open Access Journals (Sweden)

    Jun-ichi Kadokawa

    2016-04-01

    Full Text Available In this review article, the precise synthesis of functional polysaccharide materials using phosphorylase-catalyzed enzymatic reactions is presented. This particular enzymatic approach has been identified as a powerful tool in preparing well-defined polysaccharide materials. Phosphorylase is an enzyme that has been employed in the synthesis of pure amylose with a precisely controlled structure. Similarly, using a phosphorylase-catalyzed enzymatic polymerization, the chemoenzymatic synthesis of amylose-grafted heteropolysaccharides containing different main-chain polysaccharide structures (e.g., chitin/chitosan, cellulose, alginate, xanthan gum, and carboxymethyl cellulose was achieved. Amylose-based block, star, and branched polymeric materials have also been prepared using this enzymatic polymerization. Since phosphorylase shows a loose specificity for the recognition of substrates, different sugar residues have been introduced to the non-reducing ends of maltooligosaccharides by phosphorylase-catalyzed glycosylations using analog substrates such as α-d-glucuronic acid and α-d-glucosamine 1-phosphates. By means of such reactions, an amphoteric glycogen and its corresponding hydrogel were successfully prepared. Thermostable phosphorylase was able to tolerate a greater variance in the substrate structures with respect to recognition than potato phosphorylase, and as a result, the enzymatic polymerization of α-d-glucosamine 1-phosphate to produce a chitosan stereoisomer was carried out using this enzyme catalyst, which was then subsequently converted to the chitin stereoisomer by N-acetylation. Amylose supramolecular inclusion complexes with polymeric guests were obtained when the phosphorylase-catalyzed enzymatic polymerization was conducted in the presence of the guest polymers. Since the structure of this polymeric system is similar to the way that a plant vine twines around a rod, this polymerization system has been named

  4. Doubling Power Output of Starch Biobattery Treated by the Most Thermostable Isoamylase from an Archaeon Sulfolobus tokodaii.

    Science.gov (United States)

    Cheng, Kun; Zhang, Fei; Sun, Fangfang; Chen, Hongge; Percival Zhang, Y-H

    2015-08-20

    Biobattery, a kind of enzymatic fuel cells, can convert organic compounds (e.g., glucose, starch) to electricity in a closed system without moving parts. Inspired by natural starch metabolism catalyzed by starch phosphorylase, isoamylase is essential to debranch alpha-1,6-glycosidic bonds of starch, yielding linear amylodextrin - the best fuel for sugar-powered biobattery. However, there is no thermostable isoamylase stable enough for simultaneous starch gelatinization and enzymatic hydrolysis, different from the case of thermostable alpha-amylase. A putative isoamylase gene was mined from megagenomic database. The open reading frame ST0928 from a hyperthermophilic archaeron Sulfolobus tokodaii was cloned and expressed in E. coli. The recombinant protein was easily purified by heat precipitation at 80 (o)C for 30 min. This enzyme was characterized and required Mg(2+) as an activator. This enzyme was the most stable isoamylase reported with a half lifetime of 200 min at 90 (o)C in the presence of 0.5 mM MgCl2, suitable for simultaneous starch gelatinization and isoamylase hydrolysis. The cuvett-based air-breathing biobattery powered by isoamylase-treated starch exhibited nearly doubled power outputs than that powered by the same concentration starch solution, suggesting more glucose 1-phosphate generated.

  5. The N-terminus of glycogen phosphorylase b is not required for activation by adenosine 5'-monophosphate.

    Science.gov (United States)

    Bigley, Andrew N; Reinhart, Gregory D

    2010-06-15

    The, so far unsuccessful, search for selective effective inhibitors of glycogen phosphorylase for the treatment of type II diabetes has made phosphorylase an active target of research for the past 20 years. Many crystallographic structures of phosphorylase are currently available to aid in this research. However, those structures have been interpreted, at least in part, on the basis of work conducted with a proteolytically derived form of phosphorylase that lacked the N-terminus (phosphorylase b'). It has been reported that phosphorylase b' shows no allostery, neither homotropic nor heterotropic. The original report on phosphorylase b' examined the allosteric characteristics over very narrow ranges of effector and substrate concentrations and reported the presence of proteolytic cleavages in addition to the removal of the N-terminus. We have applied molecular biological techniques to generate a truncate lacking the N-terminus with known primary structure, and we have established conditions for fully quantifying the allosteric effect of AMP on glycogen phosphorylase b. We report here for the first time the full thermodynamic effect of AMP on phosphorylase b. Our findings with a truncate lacking the N-terminus show that the effect of AMP binding does not depend on the N-terminus.

  6. Unusual Starch Degradation Pathway via Cyclodextrins in the Hyperthermophilic Sulfate-Reducing Archaeon Archaeoglobus fulgidus Strain 7324▿

    Science.gov (United States)

    Labes, Antje; Schönheit, Peter

    2007-01-01

    The hyperthermophilic archaeon Archaeoglobus fulgidus strain 7324 has been shown to grow on starch and sulfate and thus represents the first sulfate reducer able to degrade polymeric sugars. The enzymes involved in starch degradation to glucose 6-phosphate were studied. In extracts of starch-grown cells the activities of the classical starch degradation enzymes, α-amylase and amylopullulanase, could not be detected. Instead, evidence is presented here that A. fulgidus utilizes an unusual pathway of starch degradation involving cyclodextrins as intermediates. The pathway comprises the combined action of an extracellular cyclodextrin glucanotransferase (CGTase) converting starch to cyclodextrins and the intracellular conversion of cyclodextrins to glucose 6-phosphate via cyclodextrinase (CDase), maltodextrin phosphorylase (Mal-P), and phosphoglucomutase (PGM). These enzymes, which are all induced after growth on starch, were characterized. CGTase catalyzed the conversion of starch to mainly β-cyclodextrin. The gene encoding CGTase was cloned and sequenced and showed highest similarity to a glucanotransferase from Thermococcus litoralis. After transport of the cyclodextrins into the cell by a transport system to be defined, these molecules are linearized via a CDase, catalyzing exclusively the ring opening of the cyclodextrins to the respective maltooligodextrins. These are degraded by a Mal-P to glucose 1-phosphate. Finally, PGM catalyzes the conversion of glucose 1-phosphate to glucose 6-phosphate, which is further degraded to pyruvate via the modified Embden-Meyerhof pathway. PMID:17921308

  7. X-ray structures of uridine phosphorylase from Vibrio cholerae in complexes with uridine, thymidine, uracil, thymine, and phosphate anion: Substrate specificity of bacterial uridine phosphorylases

    Energy Technology Data Exchange (ETDEWEB)

    Prokofev, I. I.; Lashkov, A. A., E-mail: alashkov83@gmail.com; Gabdulkhakov, A. G.; Balaev, V. V.; Seregina, T. A. [Russian Academy of Sciences, Shubnikov Institute of Crystallography of Federal Scientific Research Centre “Crystallography and Photonics” (Russian Federation); Mironov, A. S. [State Research Institute of Genetics and Selection of Industrial Microorganisms (Russian Federation); Betzel, C. [University of Hamburg (Germany); Mikhailov, A. M. [Russian Academy of Sciences, Shubnikov Institute of Crystallography of Federal Scientific Research Centre “Crystallography and Photonics” (Russian Federation)

    2016-11-15

    In many types of human tumor cells and infectious agents, the demand for pyrimidine nitrogen bases increases during the development of the disease, thus increasing the role of the enzyme uridine phosphorylase in metabolic processes. The rational use of uridine phosphorylase and its ligands in pharmaceutical and biotechnology industries requires knowledge of the structural basis for the substrate specificity of the target enzyme. This paper summarizes the results of the systematic study of the three-dimensional structure of uridine phosphorylase from the pathogenic bacterium Vibrio cholerae in complexes with substrates of enzymatic reactions—uridine, phosphate anion, thymidine, uracil, and thymine. These data, supplemented with the results of molecular modeling, were used to consider in detail the structural basis for the substrate specificity of uridine phosphorylases. It was shown for the first time that the formation of a hydrogen-bond network between the 2′-hydroxy group of uridine and atoms of the active-site residues of uridine phosphorylase leads to conformational changes of the ribose moiety of uridine, resulting in an increase in the reactivity of uridine compared to thymidine. Since the binding of thymidine to residues of uridine phosphorylase causes a smaller local strain of the β-N1-glycosidic bond in this the substrate compared to the uridine molecule, the β-N1-glycosidic bond in thymidine is more stable and less reactive than that in uridine. It was shown for the first time that the phosphate anion, which is the second substrate bound at the active site, interacts simultaneously with the residues of the β5-strand and the β1-strand through hydrogen bonding, thus securing the gate loop in a conformation.

  8. X-ray structures of uridine phosphorylase from Vibrio cholerae in complexes with uridine, thymidine, uracil, thymine, and phosphate anion: Substrate specificity of bacterial uridine phosphorylases

    Science.gov (United States)

    Prokofev, I. I.; Lashkov, A. A.; Gabdulkhakov, A. G.; Balaev, V. V.; Seregina, T. A.; Mironov, A. S.; Betzel, C.; Mikhailov, A. M.

    2016-11-01

    In many types of human tumor cells and infectious agents, the demand for pyrimidine nitrogen bases increases during the development of the disease, thus increasing the role of the enzyme uridine phosphorylase in metabolic processes. The rational use of uridine phosphorylase and its ligands in pharmaceutical and biotechnology industries requires knowledge of the structural basis for the substrate specificity of the target enzyme. This paper summarizes the results of the systematic study of the three-dimensional structure of uridine phosphorylase from the pathogenic bacterium Vibrio cholerae in complexes with substrates of enzymatic reactions—uridine, phosphate anion, thymidine, uracil, and thymine. These data, supplemented with the results of molecular modeling, were used to consider in detail the structural basis for the substrate specificity of uridine phosphorylases. It was shown for the first time that the formation of a hydrogen-bond network between the 2'-hydroxy group of uridine and atoms of the active-site residues of uridine phosphorylase leads to conformational changes of the ribose moiety of uridine, resulting in an increase in the reactivity of uridine compared to thymidine. Since the binding of thymidine to residues of uridine phosphorylase causes a smaller local strain of the β-N1-glycosidic bond in this the substrate compared to the uridine molecule, the β-N1-glycosidic bond in thymidine is more stable and less reactive than that in uridine. It was shown for the first time that the phosphate anion, which is the second substrate bound at the active site, interacts simultaneously with the residues of the β5-strand and the β1-strand through hydrogen bonding, thus securing the gate loop in a conformation

  9. Route of administration of pentobarbital affects activity of liver glycogen phosphorylase

    DEFF Research Database (Denmark)

    Mikines, K J; Sonne, B; Richter, Erik

    1986-01-01

    pentobarbital (5 mg/100 g body wt) either intraperitoneally, as a slow intravenous infusion, or as an intravenous or intracardial bolus. Times from administration of barbiturate to sampling of the liver were 10 min, 10 min, 85 +/- 32 s (mean +/- SE), and 53 +/- 10 s, respectively. Phosphorylase a activity...... in % of total phosphorylase activity was 40 +/- 2, 56 +/- 4, 82 +/- 3, and 92 +/- 2, respectively, all significantly different. Thus the route of administration of pentobarbital affects the phosphorylase a activity and should be considered when evaluating this activity. This fact can only be partially explained...

  10. NCBI nr-aa BLAST: CBRC-PTRO-18-0038 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PTRO-18-0038 ref|ZP_01507184.1| glycogen/starch/alpha-glucan phosphorylases [Burkholderia phytofirm...ans PsJN] gb|EAV08329.1| glycogen/starch/alpha-glucan phosphorylases [Burkholderia phytofirmans PsJN] ZP_01507184.1 4.8 26% ...

  11. Advanced water splitting for green hydrogen gas production through complete oxidation of starch by in vitro metabolic engineering.

    Science.gov (United States)

    Kim, Jae-Eung; Kim, Eui-Jin; Chen, Hui; Wu, Chang-Hao; Adams, Michael W W; Zhang, Y-H Percival

    2017-11-01

    Starch is a natural energy storage compound and is hypothesized to be a high-energy density chemical compound or solar fuel. In contrast to industrial hydrolysis of starch to glucose, an alternative ATP-free phosphorylation of starch was designed to generate cost-effective glucose 6-phosphate by using five thermophilic enzymes (i.e., isoamylase, alpha-glucan phosphorylase, 4-α-glucanotransferase, phosphoglucomutase, and polyphosphate glucokinase). This enzymatic phosphorolysis is energetically advantageous because the energy of α-1,4-glycosidic bonds among anhydroglucose units is conserved in the form of phosphorylated glucose. Furthermore, we demonstrated an in vitro 17-thermophilic enzyme pathway that can convert all glucose units of starch, regardless of branched and linear contents, with water to hydrogen at a theoretic yield (i.e., 12 H 2 per glucose), three times of the theoretical yield from dark microbial fermentation. The use of a biomimetic electron transport chain enabled to achieve a maximum volumetric productivity of 90.2mmol of H 2 /L/h at 20g/L starch. The complete oxidation of starch to hydrogen by this in vitro synthetic (enzymatic) biosystem suggests that starch as a natural solar fuel becomes a high-density hydrogen storage compound with a gravimetric density of more than 14% H 2 -based mass and an electricity density of more than 3000Wh/kg of starch. Copyright © 2017. Published by Elsevier Inc.

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

    Science.gov (United States)

    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.

  13. Crystal structure of sucrose phosphorylase from Bifidobacterium adolescentis

    DEFF Research Database (Denmark)

    Sprogøe, Desiree; van den Broek, Lambertus A M; Mirza, Osman

    2004-01-01

    phosphorylase from Bifidobacterium adolescentis (BiSP) refined at 1.77 A resolution. It represents the first 3D structure of a sucrose phosphorylase and is the first structure of a phosphate-dependent enzyme from the glycoside hydrolase family 13. The structure of BiSP is composed of the four domains A, B, B...... binding and reduces the size of the substrate access channel compared to other family 13 members, underlining the role of this domain in modulating the function of these enzymes. It is remarkable that the fold of the C domain is not observed in any other known hydrolases of family 13. BiSP was found...

  14. Diurnal variation in glycogen phosphorylase activity in rat liver. A quantitative histochemical study

    NARCIS (Netherlands)

    Frederiks, W. M.; Marx, F.; Bosch, K. S.

    1987-01-01

    The diurnal variations of the glycogen content and of glycogen phosphorylase activity in periportal and pericentral areas of rat liver parenchyma have been analyzed in periodic acid Schiff (PAS)-stained cryostat sections using quantitative microdensitometry. Glycogen content and phosphorylase

  15. Stabilization of Escherichia coli uridine phosphorylase by evolution and immobilization

    CSIR Research Space (South Africa)

    Visser, Daniel F

    2010-08-01

    Full Text Available nucleoside phosphorylase (BHPNP1) from the thermotolerant alkalophile Bacillus halodurans with the Escherichia coli uridine phosphorylase (EcUP) (EC 2.4.2.3) in a one-pot cascade reaction can produce 5-MU in high yield [2, 3]. The optimal operating... reaction temperature of 60?C is within the thermostability range of BHPNP, but the stability of the UP is only 40?C. This requires higher enzyme loading to offset the rate of thermal deactivation. Moreover, due to the low solubility of the reaction...

  16. Genetics Home Reference: purine nucleoside phosphorylase deficiency

    Science.gov (United States)

    ... the expand/collapse boxes. Description Purine nucleoside phosphorylase deficiency is one of several disorders that damage the immune system and cause severe combined immunodeficiency (SCID). People with SCID lack virtually all immune protection from foreign invaders such as bacteria, viruses, and ...

  17. Modelling Carbon Emissions in Calluna vulgaris–Dominated Ecosystems when Prescribed Burning and Wildfires Interact

    Science.gov (United States)

    Santana, Victor M.; Alday, Josu G.; Lee, HyoHyeMi; Allen, Katherine A.; Marrs, Rob H.

    2016-01-01

    A present challenge in fire ecology is to optimize management techniques so that ecological services are maximized and C emissions minimized. Here, we modeled the effects of different prescribed-burning rotation intervals and wildfires on carbon emissions (present and future) in British moorlands. Biomass-accumulation curves from four Calluna-dominated ecosystems along a north-south gradient in Great Britain were calculated and used within a matrix-model based on Markov Chains to calculate above-ground biomass-loads and annual C emissions under different prescribed-burning rotation intervals. Additionally, we assessed the interaction of these parameters with a decreasing wildfire return intervals. We observed that litter accumulation patterns varied between sites. Northern sites (colder and wetter) accumulated lower amounts of litter with time than southern sites (hotter and drier). The accumulation patterns of the living vegetation dominated by Calluna were determined by site-specific conditions. The optimal prescribed-burning rotation interval for minimizing annual carbon emissions also differed between sites: the optimal rotation interval for northern sites was between 30 and 50 years, whereas for southern sites a hump-backed relationship was found with the optimal interval either between 8 to 10 years or between 30 to 50 years. Increasing wildfire frequency interacted with prescribed-burning rotation intervals by both increasing C emissions and modifying the optimum prescribed-burning interval for minimum C emission. This highlights the importance of studying site-specific biomass accumulation patterns with respect to environmental conditions for identifying suitable fire-rotation intervals to minimize C emissions. PMID:27880840

  18. Modelling Carbon Emissions in Calluna vulgaris-Dominated Ecosystems when Prescribed Burning and Wildfires Interact.

    Science.gov (United States)

    Santana, Victor M; Alday, Josu G; Lee, HyoHyeMi; Allen, Katherine A; Marrs, Rob H

    2016-01-01

    A present challenge in fire ecology is to optimize management techniques so that ecological services are maximized and C emissions minimized. Here, we modeled the effects of different prescribed-burning rotation intervals and wildfires on carbon emissions (present and future) in British moorlands. Biomass-accumulation curves from four Calluna-dominated ecosystems along a north-south gradient in Great Britain were calculated and used within a matrix-model based on Markov Chains to calculate above-ground biomass-loads and annual C emissions under different prescribed-burning rotation intervals. Additionally, we assessed the interaction of these parameters with a decreasing wildfire return intervals. We observed that litter accumulation patterns varied between sites. Northern sites (colder and wetter) accumulated lower amounts of litter with time than southern sites (hotter and drier). The accumulation patterns of the living vegetation dominated by Calluna were determined by site-specific conditions. The optimal prescribed-burning rotation interval for minimizing annual carbon emissions also differed between sites: the optimal rotation interval for northern sites was between 30 and 50 years, whereas for southern sites a hump-backed relationship was found with the optimal interval either between 8 to 10 years or between 30 to 50 years. Increasing wildfire frequency interacted with prescribed-burning rotation intervals by both increasing C emissions and modifying the optimum prescribed-burning interval for minimum C emission. This highlights the importance of studying site-specific biomass accumulation patterns with respect to environmental conditions for identifying suitable fire-rotation intervals to minimize C emissions.

  19. Structural and mechanistic analysis of a β-glycoside phosphorylase identified by screening a metagenomic library.

    Science.gov (United States)

    Macdonald, Spencer S; Patel, Ankoor; Larmour, Veronica L C; Morgan-Lang, Connor; Hallam, Steven J; Mark, Brian L; Withers, Stephen G

    2018-03-02

    Glycoside phosphorylases have considerable potential as catalysts for the assembly of useful glycans for products ranging from functional foods and prebiotics to novel materials. However, the substrate diversity of currently identified phosphorylases is relatively small, limiting their practical applications. To address this limitation, we developed a high-throughput screening approach using the activated substrate 2,4-dinitrophenyl β-d-glucoside (DNPGlc) and inorganic phosphate for identifying glycoside phosphorylase activity and used it to screen a large insert metagenomic library. The initial screen, based on release of 2,4-dinitrophenyl from DNPGlc in the presence of phosphate, identified the gene bglP, encoding a retaining β-glycoside phosphorylase from the CAZy GH3 family. Kinetic and mechanistic analysis of the gene product, BglP, confirmed a double displacement ping-pong mechanism involving a covalent glycosyl-enzyme intermediate. X-ray crystallographic analysis provided insights into the phosphate-binding mode and identified a key glutamine residue in the active site important for substrate recognition. Substituting this glutamine for a serine swapped the substrate specificity from glucoside to N -acetylglucosaminide. In summary, we present a high-throughput screening approach for identifying β-glycoside phosphorylases, which was robust, simple to implement, and useful in identifying active clones within a metagenomics library. Implementation of this screen enabled discovery of a new glycoside phosphorylase class and has paved the way to devising simple ways in which enzyme specificity can be encoded and swapped, which has implications for biotechnological applications. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Short- and medium-term effects of experimental nitrogen fertilization on arthropods associated with Calluna vulgaris heathlands in north-west Spain

    International Nuclear Information System (INIS)

    Cuesta, D.; Taboada, A.; Calvo, L.; Salgado, J.M.

    2008-01-01

    We studied the short- and medium-term effects of experimental nitrogen fertilization (3 and 15 months after the treatment) on the arthropods of Calluna vulgaris heathlands in NW Spain. Three heathland sites were selected with two permanent plots per site: control and fertilized. Ammonium nitrate fertilizer (56 kg N ha -1 yr -1 ) was applied monthly and insects were caught using pitfall traps. We found mainly species-level responses to nitrogen addition. Seven species (e.g. Lochmaea suturalis) showed a consistent trend (benefited or harmed) in both periods and were proposed as possible reliable indicators of the effects of nitrogen deposition in these ecosystems. We also found variable arthropod trophic-group responses: (a) herbivores (leaf beetles, true bugs) increased in abundance on a short-term scale; (b) predators (carabid beetles, true bugs) showed opposite and less clear responses in both periods. Further long-term studies are needed to determine the mechanisms underlying the observed arthropod responses. - We observed consistent species-level and variable trophic-group responses to nitrogen addition in one of the southern-most locations for Calluna vulgaris heathlands within Europe

  1. Antimicrobial activity of selected plant species of Genera arbutus l., Bruckenthalia rchb., Calluna salisb. and Erica l. (Ericaceae

    Directory of Open Access Journals (Sweden)

    Pavlović Dragana

    2014-03-01

    Full Text Available Najpoznatiji i najviše korišćeni biljni uroantiseptik je list uve, Uvaeursi folium (Arctostaphylos uva ursi, Ericaceae. U tradicionalnoj medicini često se i druge vrste familije Ericaceae spominju u lečenju urinarnih infekcija. Provera antimikrobne aktivnosti izvršena je za sledeće biljne vrste ove familije koje samostalno rastu u flori Balkanskog poluostrva: Arbutus unedo, Bruckentalia spiculifolia, Calluna vulgaris, Erica arborea i Erica carnea.

  2. Isolation, crystallization and preliminary crystallographic analysis of Salmonella typhimurium uridine phosphorylase crystallized with 2,2′-anhydrouridine

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, Vladimir I.; Lashkov, Alexander A.; Gabdoulkhakov, Azat G.; Pavlyuk, Bogdan Ph. [A. V. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninskiy Prospect 59, 119333 Moscow (Russian Federation); Kachalova, Galina S. [Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Street 3, 142290 Pushchino, Moscow Region (Russian Federation); Betzel, Christian [Institute fur Biochemie und Lebensmittelchemie, University of Hamburg, c/o DESY, Building 22, Notkestrasse 85, 22604 Hamburg (Germany); Morgunova, Ekaterina Yu.; Zhukhlistova, Nadezhda E.; Mikhailov, Al’bert M., E-mail: amm@ns.crys.ras.ru [A. V. Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninskiy Prospect 59, 119333 Moscow (Russian Federation)

    2007-10-01

    S. typhimurium uridine phosphorylase has been isolated and crystallized in the presence of ligand. Uridine phosphorylase (UPh; EC 2.4.2.3) is a member of the pyrimidine nucleoside phosphorylase family of enzymes which catalyzes the phosphorolytic cleavage of the C—N glycoside bond of uridine, with the formation of ribose 1-phosphate and uracil. This enzyme has been shown to be important in the activation and catabolism of fluoropyrimidines. Modulation of its enzymatic activity may affect the therapeutic efficacy of chemotherapeutic agents. The structural investigation of the bacterial uridine phosphorylases, both unliganded and complexed with substrate/product analogues and inhibitors, may help in understanding the catalytic mechanism of the phosphorolytic cleavage of uridine. Salmonella typhimurium uridine phosphorylase has been crystallized with 2,2′-anhydrouridine. X-ray diffraction data were collected to 2.15 Å. Preliminary analysis of the diffraction data indicates that the crystal belongs to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 88.52, b = 123.98, c = 133.52 Å. The solvent content is 45.51%, assuming the presence of one hexamer molecule per asymmetric unit.

  3. Synthesis of glycogen from fructose in the presence of elevated levels of glycogen phosphorylase a in rat hepatocytes.

    Science.gov (United States)

    Ciudad, C J; Massagué, J; Salavert, A; Guinovart, J J

    1980-03-20

    Incubation of hepatocytes with glucose promoted the increase in the glycogen synthase (-glucose 6-phosphate/+glucose 6-phosphate) activity ratio, the decrease in the levels of phosphorylase a and a marked increase in the intracellular glycogen level. Incubation with fructose alone promoted the simultaneous activation of glycogen synthase and increase in the levels of phosphorylase a. Strikingly, glycogen deposition occurred in spite of the elevated levels of phosphorylase a. When glucose and fructose were added to the media the activation of glycogen synthase was always higher than when the hexoses were added separately. On the other hand the effects on glycogen phosphorylase were a function of the relative concentrations of both sugars. Inactivation of glycogen phosphorylase occurred when the fructose to glucose ratio was low while activation took place when the ratio was high. The simultaneous presence of glucose and fructose resulted, in all cases, in an enhancement in the deposition of glycogen. The effects described were not limited to fructose as D-glyceraldehyde, dihydroxyacetone, L-sorbose, D-tagatose and sorbitol, compounds metabolically related to fructose, provoked the same behaviour.

  4. Purification of the alpha and beta subunits of phosphorylase kinase for structural studies

    International Nuclear Information System (INIS)

    Sotiroudis, T.G.; Heilmeyer, L.M.G. Jr.; Crabb, J.W.

    1987-01-01

    Structural analysis of the alpha (Mr, 132,000) and beta (Mr, 113,000) subunits of phosphorylase kinase may provide clues to their yet unknown functions however purification remains problematic. Preparative RP-HPLC procedures yield inconveniently large, dilute solutions and concentration steps are required prior to subunit modification and fragmentation. Concentration of the β subunit usually results in significant losses due to insolubility. Using preparative SDS-polyacrylamide gel electrophoresis, they have purified the α, 7 , and β subunits from rabbit muscle phosphorylase kinase in a soluble and concentrated form suitable for structural studies. Phosphorylase kinase labelled with fluorescein isothiocyanate in the α and α' subunits and fully 14 C-S-carboxymethylated was fractionated on a 5% acrylamide Laemmli slab gel. The subunit bands were visualized by fluorescence and by SDS precipitation then excised and electroeluted in the presence of SDS using an ELUTRAP device. From 4.5 mg of enzyme applied to a 4.5 mm thick gel about 70% of the α subunit and about 90% of the β subunit were typically recovered in less than 1 ml with overnight elution

  5. Carbon allocation and decomposition of root-derived organic matter in a plant-soil system of Calluna vulgaris as affected by elevated CO2.

    NARCIS (Netherlands)

    Verburg, P.S.J.; Gorissenand, A.; Arp, W.J.

    1998-01-01

    The effect of elevated CO2 on C allocation in plant and soil was assessed using soil cores planted with 1-y-old heather (Calluna vulgaris (L.) Hull). Plants were pulse-labeled with 14CO2 at ambient and elevated CO2 and two nitrogen regimes (low and high). After harvesting the plants, the soil was

  6. Regulation of Maltodextrin Phosphorylase Synthesis in Escherichia coli by Cyclic Adenosine 3′, 5′-Monophosphate and Glucose1

    Science.gov (United States)

    Chao, Julie; Weathersbee, Carolyn J.

    1974-01-01

    Cyclic adenosine 3′, 5′-monophosphate (AMP) stimulates maltodextrin phosphorylase synthesis in Escherichia coli cells induced with maltose. A maximal effect occurs at 2 to 3 mM cyclic AMP. The action of cyclic AMP is specific, inasmuch as adenosine triphosphate, 3′-AMP, 5′-AMP, adenosine, and dibutyryl cyclic AMP are inactive. Glucose, α-methyl glucoside, 2-deoxyglucose, and pyridoxal 5′-phosphate repress maltodextrin phosphorylase synthesis. This repression is reversed by cyclic AMP. The action of cyclic AMP appears to be at the transcriptional level, since cyclic AMP fails to stimulate phosphorylase production in induced cells in which messenger ribonucleic acid synthesis has been arrested by rifampin or by inducer removal. The two other enzymes involved in the metabolism of maltose, amylomaltase and maltose permease, are also induced in this strain of E. coli and affected by glucose and cyclic AMP in a manner similar to phosphorylase. PMID:4358043

  7. Increased hepatic glycogen synthetase and decreased phosphorylase in trained rats

    DEFF Research Database (Denmark)

    Galbo, H; Saugmann, P; Richter, Erik

    1979-01-01

    Rats were either physically trained by a 12 wk swimming program or were freely eating or weight matched, sedentary controls. Trained rats had a higher relative liver weight and total hepatic glycogen synthetase (EC 2.4.1.11) activity and a lower phosphorylase (EC 2.4.1.1) activity than the other...

  8. Shrubs tracing sea surface temperature--Calluna vulgaris on the Faroe Islands.

    Science.gov (United States)

    Beil, Ilka; Buras, Allan; Hallinger, Martin; Smiljanić, Marko; Wilmking, Martin

    2015-11-01

    The climate of Central and Northern Europe is highly influenced by the North Atlantic Ocean due to heat transfer from lower latitudes. Detailed knowledge about spatio-temporal variability of sea surface temperature (SST) in that region is thus of high interest for climate and environmental research. Because of the close relations between ocean and coastal climate and the climate sensitivity of plant growth, annual rings of woody plants in coastal regions might be used as a proxy for SST. We show here for the first time the proxy potential of the common and widespread evergreen dwarf shrub Calluna vulgaris (heather), using the Faroe Islands as our case study. Despite its small and irregular ring structure, the species seems suitable for dendroecological investigations. Ring width showed high and significant correlations with summer and winter air temperatures and SST. The C. vulgaris chronology from the Faroe Islands, placed directly within the North Atlantic Current, clearly reflects variations in summer SSTs over an area between Iceland and Scotland. Utilising shrubs like C. vulgaris as easy accessible and annually resolved proxies offers an interesting possibility for reconstruction of the coupled climate-ocean system at high latitudes.

  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. Structural rearrangements of sucrose phosphorylase from Bifidobacterium adolescentis during sucrose conversion

    DEFF Research Database (Denmark)

    Mirza, Osman; Henriksen, Lars Skov; Sprogøe, Desiree

    2006-01-01

    The reaction mechanism of sucrose phosphorylase from Bifidobacterium adolescentis (BiSP) was studied by site-directed mutagenesis and x-ray crystallography. An inactive mutant of BiSP (E232Q) was co-crystallized with sucrose. The structure revealed a substrate-binding mode comparable with that se...

  11. Allozyme comparison of three Trypanosoma species (Kinetoplastida: Trypanosomatidae) of toads and frogs by starch-gel electrophoresis.

    Science.gov (United States)

    Martin, D S; Desser, S S; Hong, H

    1992-04-01

    Six metabolic enzymes, glucose-6-phosphate dehydrogenase, glucosephosphate isomerase, isocitrate dehydrogenase, malate dehydrogenase, phosphoglucomutase, and purine nucleoside phosphorylase, from clonal isolates of 3 presumptive species of Trypanosoma (T. fallisi, T. ranarum, and T. rotatorium) from 3 anuran hosts (Bufo americanus, Rana clamitans, and Rana catesbeiana) were compared using starch-gel electrophoresis. Although bands were shared among the different zymodemes of isolates of the same host genus, low genetic polymorphism of the enzyme loci was observed with few apparent shared bands between samples isolated from frogs and toads. A distance value calculated between toad and frog trypanosome isolates suggests the likelihood of long-time separation of species. Cluster analysis based on overall similarity distinguished the trypanosomes of toads and frogs as separate taxa, suggesting that host specificity and observed morphological differences are consistent with heritable allozyme differences.

  12. Architecture of Amylose Supramolecules in Form of Inclusion Complexes by Phosphorylase-Catalyzed Enzymatic Polymerization

    Directory of Open Access Journals (Sweden)

    Jun-ichi Kadokawa

    2013-07-01

    Full Text Available This paper reviews the architecture of amylose supramolecules in form of inclusion complexes with synthetic polymers by phosphorylase-catalyzed enzymatic polymerization. Amylose is known to be synthesized by enzymatic polymerization using α-d-glucose 1-phosphate as a monomer, by phosphorylase catalysis. When the phosphorylase-catalyzed enzymatic polymerization was conducted in the presence of various hydrophobic polymers, such as polyethers, polyesters, poly(ester-ether, and polycarbonates as a guest polymer, such inclusion supramolecules were formed by the hydrophobic interaction in the progress of polymerization. Because the representation of propagation in the polymerization is similar to the way that a vine of a plant grows, twining around a rod, this polymerization method for the formation of amylose-polymer inclusion complexes was proposed to be named “vine-twining polymerization”. To yield an inclusion complex from a strongly hydrophobic polyester, the parallel enzymatic polymerization system was extensively developed. The author found that amylose selectively included one side of the guest polymer from a mixture of two resemblant guest polymers, as well as a specific range in molecular weights of the guest polymers poly(tetrahydrofuran (PTHF in the vine-twining polymerization. Selective inclusion behavior of amylose toward stereoisomers of chiral polyesters, poly(lactides, also appeared in the vine-twining polymerization.

  13. Functional characterization of sucrose phosphorylase and scrR, a regulator of sucrose metabolism in Lactobacillus reuteri.

    Science.gov (United States)

    Teixeira, Januana S; Abdi, Reihaneh; Su, Marcia Shu-Wei; Schwab, Clarissa; Gänzle, Michael G

    2013-12-01

    Lactobacillus reuteri harbours alternative enzymes for sucrose metabolism, sucrose phosphorylase, fructansucrases, and glucansucrases. Sucrose phosphorylase and fructansucrases additionally contribute to raffinose metabolism. Glucansucrases and fructansucrases produce exopolysaccharides as alternative to sucrose hydrolysis. L. reuteri LTH5448 expresses a levansucrase (ftfA) and sucrose phosphorylase (scrP), both are inducible by sucrose. This study determined the contribution of scrP to sucrose and raffinose metabolism in L. reuteri LTH5448, and elucidated the role of scrR in regulation sucrose metabolism. Disruption of scrP and scrR was achieved by double crossover mutagenesis. L. reuteri LTH5448, LTH5448ΔscrP and LTH5448ΔscrR were characterized with respect to growth and metabolite formation with glucose, sucrose, or raffinose as sole carbon source. Inactivation of scrR led to constitutive transcription of scrP and ftfA, demonstrating that scrR is negative regulator. L. reuteri LTH5448 and the LTH5448ΔscrP or LTH5448ΔscrR mutant strains did not differ with respect to glucose, sucrose or raffinose utilization. However, L. reuteri LTH5448ΔscrP produced more levan, indicating that the lack of sucrose phosphorylase is compensated by an increased metabolic flux through levansucrase. In conclusion, the presence of alternate pathways for sucrose and raffinose metabolism and their regulation indicate that these substrates, which are abundant in plants, are preferred carbohydrate sources for L. reuteri. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. A novel GDP-D-glucose phosphorylase involved in quality control of the nucleoside diphosphate sugar pool in Caenorhabditis elegans and mammals.

    Science.gov (United States)

    Adler, Lital N; Gomez, Tara A; Clarke, Steven G; Linster, Carole L

    2011-06-17

    The plant VTC2 gene encodes GDP-L-galactose phosphorylase, a rate-limiting enzyme in plant vitamin C biosynthesis. Genes encoding apparent orthologs of VTC2 exist in both mammals, which produce vitamin C by a distinct metabolic pathway, and in the nematode worm Caenorhabditis elegans where vitamin C biosynthesis has not been demonstrated. We have now expressed cDNAs of the human and worm VTC2 homolog genes (C15orf58 and C10F3.4, respectively) and found that the purified proteins also display GDP-hexose phosphorylase activity. However, as opposed to the plant enzyme, the major reaction catalyzed by these enzymes is the phosphorolysis of GDP-D-glucose to GDP and D-glucose 1-phosphate. We detected activities with similar substrate specificity in worm and mouse tissue extracts. The highest expression of GDP-D-glucose phosphorylase was found in the nervous and male reproductive systems. A C. elegans C10F3.4 deletion strain was found to totally lack GDP-D-glucose phosphorylase activity; this activity was also found to be decreased in human HEK293T cells transfected with siRNAs against the human C15orf58 gene. These observations confirm the identification of the worm C10F3.4 and the human C15orf58 gene expression products as the GDP-D-glucose phosphorylases of these organisms. Significantly, we found an accumulation of GDP-D-glucose in the C10F3.4 mutant worms, suggesting that the GDP-D-glucose phosphorylase may function to remove GDP-D-glucose formed by GDP-D-mannose pyrophosphorylase, an enzyme that has previously been shown to lack specificity for its physiological D-mannose 1-phosphate substrate. We propose that such removal may prevent the misincorporation of glucosyl residues for mannosyl residues into the glycoconjugates of worms and mammals.

  15. A Novel GDP-d-glucose Phosphorylase Involved in Quality Control of the Nucleoside Diphosphate Sugar Pool in Caenorhabditis elegans and Mammals*

    Science.gov (United States)

    Adler, Lital N.; Gomez, Tara A.; Clarke, Steven G.; Linster, Carole L.

    2011-01-01

    The plant VTC2 gene encodes GDP-l-galactose phosphorylase, a rate-limiting enzyme in plant vitamin C biosynthesis. Genes encoding apparent orthologs of VTC2 exist in both mammals, which produce vitamin C by a distinct metabolic pathway, and in the nematode worm Caenorhabditis elegans where vitamin C biosynthesis has not been demonstrated. We have now expressed cDNAs of the human and worm VTC2 homolog genes (C15orf58 and C10F3.4, respectively) and found that the purified proteins also display GDP-hexose phosphorylase activity. However, as opposed to the plant enzyme, the major reaction catalyzed by these enzymes is the phosphorolysis of GDP-d-glucose to GDP and d-glucose 1-phosphate. We detected activities with similar substrate specificity in worm and mouse tissue extracts. The highest expression of GDP-d-glucose phosphorylase was found in the nervous and male reproductive systems. A C. elegans C10F3.4 deletion strain was found to totally lack GDP-d-glucose phosphorylase activity; this activity was also found to be decreased in human HEK293T cells transfected with siRNAs against the human C15orf58 gene. These observations confirm the identification of the worm C10F3.4 and the human C15orf58 gene expression products as the GDP-d-glucose phosphorylases of these organisms. Significantly, we found an accumulation of GDP-d-glucose in the C10F3.4 mutant worms, suggesting that the GDP-d-glucose phosphorylase may function to remove GDP-d-glucose formed by GDP-d-mannose pyrophosphorylase, an enzyme that has previously been shown to lack specificity for its physiological d-mannose 1-phosphate substrate. We propose that such removal may prevent the misincorporation of glucosyl residues for mannosyl residues into the glycoconjugates of worms and mammals. PMID:21507950

  16. Structural basis of the substrate specificity of Bacillus cereus adenosine phosphorylase

    Energy Technology Data Exchange (ETDEWEB)

    Dessanti, Paola [Cornell University, Ithaca, NY 14853-1301 (United States); Università di Sassari, (Italy); Zhang, Yang [Cornell University, Ithaca, NY 14853-1301 (United States); Allegrini, Simone [Università di Sassari, (Italy); Tozzi, Maria Grazia [Università di Pisa, (Italy); Sgarrella, Francesco [Università di Sassari, (Italy); Ealick, Steven E., E-mail: see3@cornell.edu [Cornell University, Ithaca, NY 14853-1301 (United States)

    2012-03-01

    Adenosine phosphorylase from B. cereus shows a strong preference for adenosine over other 6-oxopurine nucleosides. Mutation of Asp204 to asparagine reduces the efficiency of adenosine cleavage but does not affect inosine cleavage, effectively reversing the substrate specificity. The structures of D204N complexes explain these observations. Purine nucleoside phosphorylases catalyze the phosphorolytic cleavage of the glycosidic bond of purine (2′-deoxy)nucleosides, generating the corresponding free base and (2′-deoxy)ribose 1-phosphate. Two classes of PNPs have been identified: homotrimers specific for 6-oxopurines and homohexamers that accept both 6-oxopurines and 6-aminopurines. Bacillus cereus adenosine phosphorylase (AdoP) is a hexameric PNP; however, it is highly specific for 6-aminopurines. To investigate the structural basis for the unique substrate specificity of AdoP, the active-site mutant D204N was prepared and kinetically characterized and the structures of the wild-type protein and the D204N mutant complexed with adenosine and sulfate or with inosine and sulfate were determined at high resolution (1.2–1.4 Å). AdoP interacts directly with the preferred substrate through a hydrogen-bond donation from the catalytically important residue Asp204 to N7 of the purine base. Comparison with Escherichia coli PNP revealed a more optimal orientation of Asp204 towards N7 of adenosine and a more closed active site. When inosine is bound, two water molecules are interposed between Asp204 and the N7 and O6 atoms of the nucleoside, thus allowing the enzyme to find alternative but less efficient ways to stabilize the transition state. The mutation of Asp204 to asparagine led to a significant decrease in catalytic efficiency for adenosine without affecting the efficiency of inosine cleavage.

  17. Nitrogen deposition increases the acquisition of phosphorus and potassium by heather Calluna vulgaris

    International Nuclear Information System (INIS)

    Rowe, Edwin C.; Smart, Simon M.; Kennedy, Valerie H.; Emmett, Bridget A.; Evans, Christopher D.

    2008-01-01

    Increased plant productivity due to nitrogen pollution increases the strength of the global carbon sink, but is implicated in plant diversity loss. However, modelling and experimental studies have suggested that these effects are constrained by availability of other nutrients. In a survey of element concentrations in Calluna vulgaris across an N deposition gradient in the UK, shoot concentrations of N and more surprisingly phosphorus and potassium were positively correlated with N deposition; tissue N/P ratio even decreased with N deposition. Elevated P and K concentrations possibly resulted from improved acquisition due to additional enzyme production or mycorrhizal activity. Heather occurs on organic soils where nutrient limitations are likely due to availability constraints rather than small stocks. However, if this effect extends to other plant and soil types, effects of N deposition on C sinks and plant competition may not be as constrained by availability of other nutrients as previously proposed. - Heather tissue phosphorus and potassium concentrations increased across a nitrogen deposition gradient, implying that nitrogen limited acquisition of other plant nutrients

  18. In silico binding analysis and SAR elucidations of newly designed benzopyrazine analogs as potent inhibitors of thymidine phosphorylase.

    Science.gov (United States)

    Taha, Muhammad; Ismail, Nor Hadiani; Imran, Syahrul; Rahim, Fazal; Wadood, Abdul; Al Muqarrabun, Laode Muhammad Ramadhan; Khan, Khalid Mohammed; Ghufran, Mehreen; Ali, Muhammad

    2016-10-01

    Thymidine phosphorylase (TP) is up regulated in wide variety of solid tumors and therefore presents a remarkable target for drug discovery in cancer. A novel class of extremely potent TPase inhibitors based on benzopyrazine (1-28) has been developed and evaluated against thymidine phosphorylase enzyme. Out of these twenty-eight analogs eleven (11) compounds 1, 4, 14, 15, 16, 17, 18, 19, 20, 24 and 28 showed potent thymidine phosphorylase inhibitory potentials with IC50 values ranged between 3.20±0.30 and 37.60±1.15μM when compared with the standard 7-Deazaxanthine (IC50=38.68±4.42μM). Structure-activity relationship was established and molecular docking studies were performed to determine the binding interactions of these newly synthesized compounds. Current studies have revealed that these compounds established stronger hydrogen bonding networks with active site residues as compare to the standard compound 7DX. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. The diagnostic value of immunohistochemically detected methylthioadenosine phosphorylase deficiency in malignant pleural mesotheliomas

    DEFF Research Database (Denmark)

    Zimling, Zarah Glad; Jørgensen, Anne; Santoni-Rugiu, Eric

    2012-01-01

      Malignant pleural mesothelioma (MPM) often causes diagnostic difficulties for pathologists. We assessed whether loss of methylthioadenosine phosphorylase (MTAP), a key enzyme in the intracellular recycling of adenosine triphosphate (ATP) often deleted in MPM, could be detected with immunohistoc...

  20. 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.

  1. Chemoenzymatic Synthesis of beta-D-Glucosides using Cellobiose Phosphorylase from Clostridium thermocellum

    Czech Academy of Sciences Publication Activity Database

    De Winter, K.; Van Renterghem, L.; Wuyts, K.; Pelantová, Helena; Křen, Vladimír; Soetaert, W.; Desmet, T.

    2015-01-01

    Roč. 357, č. 8 (2015), s. 1961-1969 ISSN 1615-4150 R&D Projects: GA MŠk(CZ) LD13042; GA MŠk(CZ) 7E11011 Institutional support: RVO:61388971 Keywords : cellobiose phosphorylase * cross-linked enzyme aggregates * beta-glucosides Subject RIV: CE - Biochemistry Impact factor: 6.453, year: 2015

  2. 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...

  3. 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.

  4. Preliminary crystallographic studies of purine nucleoside phosphorylase from the cariogenic pathogen Streptococcus mutans

    International Nuclear Information System (INIS)

    Hou, Qiao-Ming; Liu, Xiang; Brostromer, Erik; Li, Lan-Fen; Su, Xiao-Dong

    2009-01-01

    Purine nucleoside phosphorylase (PNP), which is a pivotal enzyme in the nucleotide-salvage pathway, has been expressed in Escherichia coli strain BL21 (DE3) in a soluble form at a high level. After purification of the PNP enzyme, the protein was crystallized using the sitting-drop vapour-diffusion technique. The punA gene of the cariogenic pathogen Streptococcus mutans encodes purine nucleoside phosphorylase (PNP), which is a pivotal enzyme in the nucleotide-salvage pathway, catalyzing the phosphorolysis of purine nucleosides to generate purine bases and α-ribose 1-phosphate. In the present work, the PNP protein was expressed in Escherichia coli strain BL21 (DE3) in a soluble form at a high level. After purification of the PNP enzyme, the protein was crystallized using the sitting-drop vapour-diffusion technique; the crystals diffracted to 1.6 Å resolution at best. The crystals belonged to space group H3, with unit-cell parameters a = b = 113.0, c = 60.1 Å

  5. Structure of a complex of uridine phosphorylase from Yersinia pseudotuberculosis with the modified bacteriostatic antibacterial drug determined by X-ray crystallography and computer analysis

    Energy Technology Data Exchange (ETDEWEB)

    Balaev, V. V.; Lashkov, A. A., E-mail: alashkov83@gmail.com; Gabdoulkhakov, A. G.; Seregina, T. A.; Dontsova, M. V.; Mikhailov, A. M. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2015-03-15

    Pseudotuberculosis and bubonic plague are acute infectious diseases caused by the bacteria Yersinia pseudotuberculosis and Yersinia pestis. These diseases are treated, in particular, with trimethoprim and its modified analogues. However, uridine phosphorylases (pyrimidine nucleoside phosphorylases) that are present in bacterial cells neutralize the action of trimethoprim and its modified analogues on the cells. In order to reveal the character of the interaction of the drug with bacterial uridine phosphorylase, the atomic structure of the unligated molecule of uridine-specific pyrimidine nucleoside phosphorylase from Yersinia pseudotuberculosis (YptUPh) was determined by X-ray diffraction at 1.7 Å resolution with high reliability (R{sub work} = 16.2, R{sub free} = 19.4%; r.m.s.d. of bond lengths and bond angles are 0.006 Å and 1.005°, respectively; DPI = 0.107 Å). The atoms of the amino acid residues of the functionally important secondary-structure elements—the loop L9 and the helix H8—of the enzyme YptUPh were located. The three-dimensional structure of the complex of YptUPh with modified trimethoprim—referred to as 53I—was determined by the computer simulation. It was shown that 53I is a pseudosubstrate of uridine phosphorylases, and its pyrimidine-2,4-diamine group is located in the phosphate-binding site of the enzyme YptUPh.

  6. Structure of a complex of uridine phosphorylase from Yersinia pseudotuberculosis with the modified bacteriostatic antibacterial drug determined by X-ray crystallography and computer analysis

    International Nuclear Information System (INIS)

    Balaev, V. V.; Lashkov, A. A.; Gabdoulkhakov, A. G.; Seregina, T. A.; Dontsova, M. V.; Mikhailov, A. M.

    2015-01-01

    Pseudotuberculosis and bubonic plague are acute infectious diseases caused by the bacteria Yersinia pseudotuberculosis and Yersinia pestis. These diseases are treated, in particular, with trimethoprim and its modified analogues. However, uridine phosphorylases (pyrimidine nucleoside phosphorylases) that are present in bacterial cells neutralize the action of trimethoprim and its modified analogues on the cells. In order to reveal the character of the interaction of the drug with bacterial uridine phosphorylase, the atomic structure of the unligated molecule of uridine-specific pyrimidine nucleoside phosphorylase from Yersinia pseudotuberculosis (YptUPh) was determined by X-ray diffraction at 1.7 Å resolution with high reliability (R work = 16.2, R free = 19.4%; r.m.s.d. of bond lengths and bond angles are 0.006 Å and 1.005°, respectively; DPI = 0.107 Å). The atoms of the amino acid residues of the functionally important secondary-structure elements—the loop L9 and the helix H8—of the enzyme YptUPh were located. The three-dimensional structure of the complex of YptUPh with modified trimethoprim—referred to as 53I—was determined by the computer simulation. It was shown that 53I is a pseudosubstrate of uridine phosphorylases, and its pyrimidine-2,4-diamine group is located in the phosphate-binding site of the enzyme YptUPh

  7. Structure of a complex of uridine phosphorylase from Yersinia pseudotuberculosis with the modified bacteriostatic antibacterial drug determined by X-ray crystallography and computer analysis

    Science.gov (United States)

    Balaev, V. V.; Lashkov, A. A.; Gabdoulkhakov, A. G.; Seregina, T. A.; Dontsova, M. V.; Mikhailov, A. M.

    2015-03-01

    Pseudotuberculosis and bubonic plague are acute infectious diseases caused by the bacteria Yersinia pseudotuberculosis and Yersinia pestis. These diseases are treated, in particular, with trimethoprim and its modified analogues. However, uridine phosphorylases (pyrimidine nucleoside phosphorylases) that are present in bacterial cells neutralize the action of trimethoprim and its modified analogues on the cells. In order to reveal the character of the interaction of the drug with bacterial uridine phosphorylase, the atomic structure of the unligated molecule of uridine-specific pyrimidine nucleoside phosphorylase from Yersinia pseudotuberculosis ( YptUPh) was determined by X-ray diffraction at 1.7 Å resolution with high reliability ( R work = 16.2, R free = 19.4%; r.m.s.d. of bond lengths and bond angles are 0.006 Å and 1.005°, respectively; DPI = 0.107 Å). The atoms of the amino acid residues of the functionally important secondary-structure elements—the loop L9 and the helix H8—of the enzyme YptUPh were located. The three-dimensional structure of the complex of YptUPh with modified trimethoprim—referred to as 53I—was determined by the computer simulation. It was shown that 53I is a pseudosubstrate of uridine phosphorylases, and its pyrimidine-2,4-diamine group is located in the phosphate-binding site of the enzyme YptUPh.

  8. 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

  9. 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...

  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. 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.

  12. 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.

  13. 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

  14. Can Crystal Symmetry and Packing Influence the Active Site Conformation of Homohexameric Purine Nucleoside Phosphorylases?

    Directory of Open Access Journals (Sweden)

    Marija Luić

    2016-06-01

    Full Text Available It is generaly believed that enzymes retain most of their functionality in the crystal form due to the large solvent content of protein crystals. This is facilitated by the fact that their natural environment in solution is not too far from the one found in the crystal form. Nevertheless, if the nature of the enzyme is such to require conformational changes, overcoming of the crystal packing constraints may prove to be too difficult. Such conformational change is present in one class of enzymes (purine nucleoside phosphorylases, that is the subject of our scientific interest for many years. The influence of crystal symmetry and crystal packing on the conformation of the active sites in the case of homohexameric purine nucleoside phosphorylases is presented and analysed. This work is licensed under a Creative Commons Attribution 4.0 International License.

  15. 2-O-α-D-glucosylglycerol phosphorylase from Bacillus selenitireducens MLS10 possessing hydrolytic activity on β-D-glucose 1-phosphate.

    Directory of Open Access Journals (Sweden)

    Takanori Nihira

    Full Text Available The glycoside hydrolase family (GH 65 is a family of inverting phosphorylases that act on α-glucosides. A GH65 protein (Bsel_2816 from Bacillus selenitireducens MLS10 exhibited inorganic phosphate (Pi-dependent hydrolysis of kojibiose at the rate of 0.43 s(-1. No carbohydrate acted as acceptor for the reverse phosphorolysis using β-D-glucose 1-phosphate (βGlc1P as donor. During the search for a suitable acceptor, we found that Bsel_2816 possessed hydrolytic activity on βGlc1P with a k cat of 2.8 s(-1; moreover, such significant hydrolytic activity on sugar 1-phosphate had not been reported for any inverting phosphorylase. The H2 (18O incorporation experiment and the anomeric analysis during the hydrolysis of βGlc1P revealed that the hydrolysis was due to the glucosyl-transferring reaction to a water molecule and not a phosphatase-type reaction. Glycerol was found to be the best acceptor to generate 2-O-α-D-glucosylglycerol (GG at the rate of 180 s(-1. Bsel_2816 phosphorolyzed GG through sequential Bi-Bi mechanism with a k cat of 95 s(-1. We propose 2-O-α-D-glucopyranosylglycerol: phosphate β-D-glucosyltransferase as the systematic name and 2-O-α-D-glucosylglycerol phosphorylase as the short name for Bsel_2816. This is the first report describing a phosphorylase that utilizes polyols, and not carbohydrates, as suitable acceptor substrates.

  16. 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)

  17. 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).

  18. 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

  19. Three-dimensional structure of E. Coli purine nucleoside phosphorylase at 0.99 Å resolution

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, V. I., E-mail: tostars@mail.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Abramchik, Yu. A., E-mail: ugama@yandex.ru [Russian Academy of Sciences, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry (Russian Federation); Zhukhlistova, N. E., E-mail: inna@ns.crys.ras.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Muravieva, T. I.; Esipov, R. S. [Russian Academy of Sciences, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry (Russian Federation); Kuranova, I. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2016-03-15

    Purine nucleoside phosphorylases (PNPs) catalyze the reversible phosphorolysis of nucleosides and are key enzymes involved in nucleotide metabolism. They are essential for normal cell function and can catalyze the transglycosylation. Crystals of E. coli PNP were grown in microgravity by the capillary counterdiffusion method through a gel layer. The three-dimensional structure of the enzyme was determined by the molecular-replacement method at 0.99 Å resolution. The structural features are considered, and the structure of E. coli PNP is compared with the structures of the free enzyme and its complexes with purine base derivatives established earlier. A comparison of the environment of the purine base in the complex of PNP with formycin A and of the pyrimidine base in the complex of uridine phosphorylase with thymidine revealed the main structural features of the base-binding sites. Coordinates of the atomic model determined with high accuracy were deposited in the Protein Data Bank (PDB-ID: 4RJ2).

  20. Quantification of the glycogen cascade system: the ultrasensitive responses of liver glycogen synthase and muscle phosphorylase are due to distinctive regulatory designs

    Directory of Open Access Journals (Sweden)

    Venkatesh KV

    2005-05-01

    Full Text Available Abstract Background Signaling pathways include intricate networks of reversible covalent modification cycles. Such multicyclic enzyme cascades amplify the input stimulus, cause integration of multiple signals and exhibit sensitive output responses. Regulation of glycogen synthase and phosphorylase by reversible covalent modification cycles exemplifies signal transduction by enzyme cascades. Although this system for regulating glycogen synthesis and breakdown appears similar in all tissues, subtle differences have been identified. For example, phosphatase-1, a dephosphorylating enzyme of the system, is regulated quite differently in muscle and liver. Do these small differences in regulatory architecture affect the overall performance of the glycogen cascade in a specific tissue? We address this question by analyzing the regulatory structure of the glycogen cascade system in liver and muscle cells at steady state. Results The glycogen cascade system in liver and muscle cells was analyzed at steady state and the results were compared with literature data. We found that the cascade system exhibits highly sensitive switch-like responses to changes in cyclic AMP concentration and the outputs are surprisingly different in the two tissues. In muscle, glycogen phosphorylase is more sensitive than glycogen synthase to cyclic AMP, while the opposite is observed in liver. Furthermore, when the liver undergoes a transition from starved to fed-state, the futile cycle of simultaneous glycogen synthesis and degradation switches to reciprocal regulation. Under such a transition, different proportions of active glycogen synthase and phosphorylase can coexist due to the varying inhibition of glycogen-synthase phosphatase by active phosphorylase. Conclusion The highly sensitive responses of glycogen synthase in liver and phosphorylase in muscle to primary stimuli can be attributed to distinctive regulatory designs in the glycogen cascade system. The different

  1. Ionic liquids as cosolvents for glycosylation by sucrose phosphorylase: balancing acceptor solubility and enzyme stability

    Czech Academy of Sciences Publication Activity Database

    De Winter, K.; Verlinden, K.; Křen, Vladimír; Weignerová, Lenka; Soetaert, W.; Desmet, T.

    2013-01-01

    Roč. 15, č. 7 (2013), s. 1949-1955 ISSN 1463-9262 R&D Projects: GA MŠk(CZ) 7E11011 Institutional support: RVO:61388971 Keywords : DISACCHARIDE PHOSPHORYLASES * THERMAL-STABILITY * ALPHA-GLUCOSIDASE Subject RIV: CE - Biochemistry Impact factor: 6.852, year: 2013

  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. 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

  4. Interactions of trimeric purine nucleoside phosphorylases with ground state analogues - calorimetric and fluorimetric studies

    Czech Academy of Sciences Publication Activity Database

    Wielgus-Kutrowska, B.; Frank, J.; Holý, Antonín; Koellner, G.; Bzowska, A.

    2003-01-01

    Roč. 22, 5/8 (2003), s. 1695-1698 ISSN 1525-7770 Grant - others:PCSR(PL) 6 P04A04416; PCSR(PL) 3 P04A03524 Institutional research plan: CEZ:AV0Z4055905 Keywords : purine nucleoside phosphorylase * fluorescence Subject RIV: CC - Organic Chemistry Impact factor: 0.813, year: 2003

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Peptide microarray analysis of substrate specificity of the transmembrane Ser/Thr kinase KPI-2 reveals reactivity with cystic fibrosis transmembrane conductance regulator and phosphorylase.

    Science.gov (United States)

    Wang, Hong; Brautigan, David L

    2006-11-01

    Human lemur (Lmr) kinases are predicted to be Tyr kinases based on sequences and are related to neurotrophin receptor Trk kinases. This study used homogeneous recombinant KPI-2 (Lmr2, LMTK2, Cprk, brain-enriched protein kinase) kinase domain and a library of 1,154 peptides on a microarray to analyze substrate specificity. We found that KPI-2 is strictly a Ser/Thr kinase that reacts with Ser either preceded by or followed by Pro residues but unlike other Pro-directed kinases does not strictly require an adjacent Pro residue. The most reactive peptide in the library corresponds to Ser-737 of cystic fibrosis transmembrane conductance regulator, and the recombinant R domain of cystic fibrosis transmembrane conductance regulator was a preferred substrate. Furthermore the KPI-2 kinase phosphorylated peptides corresponding to the single site in phosphorylase and purified phosphorylase b, making this only the second known phosphorylase b kinase. Phosphorylase was used as a specific substrate to show that KPI-2 is inhibited in living cells by addition of nerve growth factor or serum. The results demonstrate the utility of the peptide library to probe specificity and discover kinase substrates and offer a specific assay that reveals hormonal regulation of the activity of this unusual transmembrane kinase.

  10. Purine nucleoside phosphorylase deficiency in two unrelated Saudi patients

    International Nuclear Information System (INIS)

    Alangari, Abdullah; AlHarbi, Abdullah; AlGhonaium Abdulaziz; Santisteban, Ines; Hershfield, Michael

    2009-01-01

    Purine nucleoside phosphorylase (PNP) deficiency is a rare autosomal recessive metabolic disorder that results in combined immunodeficiency, neurologic dysfunction and autoimmunity. PNP deficiency has never been reported from Saudi Arabia or in patients with an Arabic ethnic background. We report on two Saudi girls with PNP deficiency. Both showed severe lymphopenia and neurological involvement. Sequencing of the PNP gene of one girl revealed a novel missense mutation Pro146>Leu in exon 4 due to a change in the codon from CCT>CTT. Expression of PNP (146L) cDNA in E coli indicated that the mutation greatly reduced, but did not completely eliminate PNP activity. (author)

  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. 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

  13. 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.

  14. 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.

  15. 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

  16. Use of Calluna vulgaris to detect signals of nitrogen deposition across an urban-rural gradient

    Science.gov (United States)

    Power, S. A.; Collins, C. M.

    2010-05-01

    Densely populated cities can experience high concentrations of traffic-derived pollutants, with oxides of nitrogen and ammonia contributing significantly to the overall nitrogen (N) budget of urban ecosystems. This study investigated changes in the biochemistry of in situ Calluna vulgaris plants to detect signals of N deposition across an urban-rural gradient from central London to rural Surrey, UK. Foliar N concentrations and δ 15N signatures were higher, and C/N ratios lower, in urban areas receiving the highest rates of N deposition. Plant phosphorus (P) concentrations were also highest in these areas, suggesting that elevated rates of N deposition are unlikely to result in progressive P-limitation in urban habitats. Free amino acid concentrations were positively related to N deposition for asparagine, glutamine, glycine, phenylalanine, isoleucine, leucine and lysine. Overall, relationships between tissue chemistry and N deposition were similar for oxidised, reduced and total N, although the strength of relationships varied with the different biochemical indicators. The results of this study indicate that current rates of N deposition are having substantial effects on plant biochemistry in urban areas, with likely implications for the biodiversity and functioning of urban ecosystems.

  17. Polysaccharide fraction from higher plants which strongly interacts with the cytosolic phosphorylase isozyme. I. Isolation and characterization

    International Nuclear Information System (INIS)

    Yang, Yi; Steup, M.

    1990-01-01

    From leaves of Spinacia oleracea L. or from Pisum sativum L. and from cotyledons of germinating pea seeds a high molecular weight polysaccharide fraction was isolated. The apparent size of the fraction, as determined by gel filtration, was similar to that of dextran blue. Following acid hydrolysis the monomer content of the polysaccharide preparation was studied using high pressure liquid and thin layer chromatography. Glucose, galactose, arabinose, and ribose were the main monosaccharide compounds. The native polysaccharide preparation interacted strongly with the cytosolic isozyme of phosphorylase (EC 2.4.1.1). Interaction with the plastidic phosphorylase isozyme(s) was by far weaker. Interaction with the cytosolic isozyme was demonstrated by affinity electrophoresis, kinetic measurements, and by 14 C-labeling experiments in which the glucosyl transfer from [ 14 C]glucose 1-phosphate to the polysaccharide preparation was monitored

  18. Potential Propagation by Seed and Cuttings of the Azorean Native Calluna vulgaris (L. Hull

    Directory of Open Access Journals (Sweden)

    Maria João Pereira

    2014-01-01

    Full Text Available This work investigates the potential propagation by seed and cuttings of the Azorean native Calluna vulgaris (L. Hull. for landscape conservation. With that purpose we have performed several germination and cuttings trials, using plant material from wild populations of this species. In the germination trials, we tested the effects of photoperiod length (8 and 16 h, temperature (10, 15, 20, and 20–10°C, seed age (6, 108, and 270 days, temperature of seed storage (4°C and room temperature, and seed surface sterilization on the germination characteristics. In the cuttings trials, we tested the effects of stem cutting type, cultural conditions, cuttings’ harvest month, and rooting substrates on the rooting percentages. The best percentages of germination, 93 and 90%, were obtained with fresh seeds and surface sterilized and sown under an 8 h photoperiod and with temperatures of 10°C or 15°C, respectively; germination after seed storage during 270 days is significantly superior (71% when seeds are stored at 4°C. The best percentages of rooting were achieved for straight (96% or heel cuttings (90% harvested in March, planted on soil from natural stands of C. vulgaris and Erica azorica Hochst., outdoors in half shade, and partially covered with transparent polyethylene film.

  19. 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

  20. 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.

  1. 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®

  2. Structural basis of the substrate specificity of Bacillus cereus adenosine phosphorylase

    Energy Technology Data Exchange (ETDEWEB)

    Dessanti, Paola; Zhang, Yang; Allegrini, Simone; Tozzi, Maria Grazia; Sgarrella, Francesco; Ealick, Steven E. (Cornell); (Sassari); (Pisa)

    2012-10-08

    Purine nucleoside phosphorylases catalyze the phosphorolytic cleavage of the glycosidic bond of purine (2{prime}-deoxy)nucleosides, generating the corresponding free base and (2{prime}-deoxy)ribose 1-phosphate. Two classes of PNPs have been identified: homotrimers specific for 6-oxopurines and homohexamers that accept both 6-oxopurines and 6-aminopurines. Bacillus cereus adenosine phosphorylase (AdoP) is a hexameric PNP; however, it is highly specific for 6-aminopurines. To investigate the structural basis for the unique substrate specificity of AdoP, the active-site mutant D204N was prepared and kinetically characterized and the structures of the wild-type protein and the D204N mutant complexed with adenosine and sulfate or with inosine and sulfate were determined at high resolution (1.2-1.4 {angstrom}). AdoP interacts directly with the preferred substrate through a hydrogen-bond donation from the catalytically important residue Asp204 to N7 of the purine base. Comparison with Escherichia coli PNP revealed a more optimal orientation of Asp204 towards N7 of adenosine and a more closed active site. When inosine is bound, two water molecules are interposed between Asp204 and the N7 and O6 atoms of the nucleoside, thus allowing the enzyme to find alternative but less efficient ways to stabilize the transition state. The mutation of Asp204 to asparagine led to a significant decrease in catalytic efficiency for adenosine without affecting the efficiency of inosine cleavage.

  3. 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.

  4. 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.

  5. 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.

  6. Synthesis, molecular docking study and thymidine phosphorylase inhibitory activity of 3-formylcoumarin derivatives.

    Science.gov (United States)

    Taha, Muhammad; Adnan Ali Shah, Syed; Afifi, Muhammad; Imran, Syahrul; Sultan, Sadia; Rahim, Fazal; Hadiani Ismail, Nor; Mohammed Khan, Khalid

    2018-03-01

    Thymidine phosphorylase (TP) over expression plays role in several pathological conditions, such as rheumatoid arthritis, chronic inflammatory diseases, psoriasis, and tumor angiogenesis. The inhibitor of this enzyme plays an important role in preventing the serious threat due to over expression of TP. In this regard, a series of seventeenanalogs of 3-formylcoumarin (1-17) were synthesized, characterized by 1 HNMR and EI-MS and screened for thymidine phosphorylaseinhibitory activity. All analogs showed a variable degree of thymidine phosphorylase inhibition with IC 50 values ranging between 0.90 ± 0.01 and 53.50 ± 1.20 μM when compared with the standard inhibitor 7-Deazaxanthine having IC 50 value 38.68 ± 1.12 μM. Among the series, fifteenanalogs such as 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 16 and 17 showed excellent inhibition which is many folds better than the standard 7-Deazaxanthine whiletwo analogs 13 and 14 showed good inhibition. The structure activity relationship (SAR) was mainly based upon by bring about difference of substituents on phenyl ring. Molecular docking study was carried out to understand the binding interaction of the most active analogs. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. 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.

  8. 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.

  9. 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.

  10. Synthesis of Hyperbranched Glycoconjugates by the Combined Action of Potato Phosphorylase and Glycogen Branching Enzyme from Deinococcus geothermalis

    Directory of Open Access Journals (Sweden)

    Katja Loos

    2012-02-01

    Full Text Available Potato phosphorylase is able to synthesize linear polyglucans from maltoheptaose primers. By coupling maltoheptaose to butane diamine, tris(2-aminoethylamine and amine functionalized amine functionalized poly ethyleneglycol (PEG, new primer molecules became available. The resulting di-, tri- and macro-primers were incubated with potato phosphorylase and glycogen branching enzyme from Deinococcus geothermalis. Due to the action of both enzymes, hyperbranched polyglucan arms were grown from the maltoheptaose derivatives with a maximum degree of branching of 11%. The size of the synthesized hyperbranched polyglucans could be controlled by the ratio monomer over primer. About 60%–80% of the monomers were incorporated in the glycoconjugates. The resulting hyperbranched glycoconjugates were subjected to Dynamic Light Scattering (DLS measurements in order to determine the hydrodynamic radius and it became obvious that the structures formed agglomerates in the range of 14–32 nm.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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).

  17. 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.

  18. Three-dimensional structures of unligated uridine phosphorylase from Yersinia pseudotuberculosis at 1.4 Å resolution and its complex with an antibacterial drug

    Science.gov (United States)

    Balaev, V. V.; Lashkov, A. A.; Gabdulkhakov, A. G.; Dontsova, M. V.; Mironov, A. S.; Betzel, C.; Mikhailov, A. M.

    2015-07-01

    Uridine phosphorylases play an essential role in the cellular metabolism of some antibacterial agents. Acute infectious diseases (bubonic plague, yersiniosis, pseudotuberculosis, etc., caused by bacteria of the genus Yersinia) are treated using both sulfanilamide medicines and antibiotics, including trimethoprim. The action of an antibiotic on a bacterial cell is determined primarily by the character of its interactions with cellular components, including those which are not targets (for example, with pyrimidine phosphorylases). This type of interaction should be taken into account in designing drugs. The three-dimensional structure of uridine phosphorylase from the bacterium Yersinia pseudotuberculosis ( YptUPh) with the free active site was determined for the first time by X-ray crystallography and refined at 1.40 Å resolution (DPI = 0.062 Å; ID PDB: 4OF4). The structure of the complex of YptUPh with the bacteriostatic drug trimethoprim was studied by molecular docking and molecular dynamics methods. The trimethoprim molecule was shown to be buffered by the enzyme YptUPh, resulting in a decrease in the efficiency of the treatment of infectious diseases caused by bacteria of the genus Yersinia with trimethoprim.

  19. 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...

  20. 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...

  1. 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

  2. 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.

  3. 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

  4. Synthesis of (benzimidazol-2-yl)aniline derivatives as glycogen phosphorylase inhibitors.

    Science.gov (United States)

    Galal, Shadia A; Khattab, Muhammad; Andreadaki, Fotini; Chrysina, Evangelia D; Praly, Jean-Pierre; Ragab, Fatma A F; El Diwani, Hoda I

    2016-11-01

    A series of (benzimidazol-2-yl)-aniline (1) derivatives has been synthesized and evaluated as glycogen phosphorylase (GP) inhibitors. Kinetics studies revealed that compounds displaying a lateral heterocyclic residue with several heteroatoms (series 3 and 5) exhibited modest inhibitory properties with IC 50 values in the 400-600μM range. Arylsulfonyl derivatives 7 (Ar: phenyl) and 9 (Ar: o-nitrophenyl) of 1 exhibited the highest activity (series 2) among the studied compounds (IC 50 324μM and 357μM, respectively) with stronger effect than the p-tolyl analogue 8. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. 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.

  6. Crystallization of uridine phosphorylase from Shewanella oneidensis MR-1 in the laboratory and under microgravity and preliminary X-ray diffraction analysis

    International Nuclear Information System (INIS)

    Safonova, Tatyana N.; Mordkovich, Nadezhda N.; Polyakov, Konstantin M.; Manuvera, Valentin A.; Veiko, Vladimir P.; Popov, Vladimir O.

    2012-01-01

    High-quality crystals of uridine phosphorylase from Shewanella oneidensis were grown under microgravity conditions. X-ray diffraction data were collected to a resolution of 0.95 Å. Uridine phosphorylase (UDP, EC 2.4.2.3), a key enzyme in the pyrimidine salvage pathway, catalyses the reversible phosphorolysis of uridine to uracil and ribose 1-phosphate. The gene expression of UDP from Shewanella oneidensis MR-1 was performed in the recipient strain Escherichia coli. The UDP protein was crystallized on earth (in the free form and in complex with uridine as the substrate) by the hanging-drop vapour-diffusion method at 296 K and under microgravity conditions (in the free form) aboard the Russian Segment of the International Space Station by the capillary counter-diffusion method. The data sets were collected to a resolution of 1.9 Å from crystals of the free form grown on earth, 1.6 Å from crystals of the complex with uridine and 0.95 Å from crystals of the free form grown under microgravity. All crystals belong to the space group P2 1 and have similar unit-cell parameters. The crystal of uridine phosphorylase grown under microgravity diffracted to ultra-high resolution and gave high-quality X-ray diffraction data

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Structural basis for the mechanism of inhibition of uridine phosphorylase from Salmonella typhimurium

    Energy Technology Data Exchange (ETDEWEB)

    Lashkov, A. A.; Zhukhlistova, N. E.; Sotnichenko, S. E.; Gabdulkhakov, A. G.; Mikhailov, A. M., E-mail: amm@ns.crys.ras.ru [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2010-01-15

    The three-dimensional structures of three complexes of Salmonella typhimurium uridine phosphorylase with the inhibitor 2,2'-anhydrouridine, the substrate PO{sub 4}, and with both the inhibitor 2,2'-anhydrouridine and the substrate PO{sub 4} (a binary complex) were studied in detail by X-ray diffraction. The structures of the complexes were refined at 2.38, 1.5, and 1.75 A resolution, respectively. Changes in the three-dimensional structure of the subunits in different crystal structures are considered depending on the presence or absence of the inhibitor molecule and (or) the phosphate ion in the active site of the enzyme. The presence of the phosphate ion in the phosphate-binding site was found to substantially change the orientations of the side chains of the amino-acid residues Arg30, Arg91, and Arg48 coordinated to this ion. A comparison showed that the highly flexible loop L9 is unstable. The atomic coordinates of the refined structures of the complexes and the corresponding structure factors were deposited in the Protein Data Bank (their PDB ID codes are 3DD0 and 3C74). The experimental data on the spatial reorganization of the active site caused by changes in its functional state from the unligated to the completely inhibited state suggest the structural basis for the mechanism of inhibition of Salmonella typhimurium uridine phosphorylase.

  12. Purification, crystallization and preliminary X-ray diffraction study on pyrimidine nucleoside phosphorylase TTHA1771 from Thermus thermophilus HB8

    International Nuclear Information System (INIS)

    Shimizu, Katsumi; Kunishima, Naoki

    2007-01-01

    The pyrimidine nucleoside phosphorylase TTHA1771 from T. thermophilus HB8 has been overexpressed, purified and crystallized. The crystals diffract X-rays to 1.8 Å resolution using synchrotron radiation. Pyrimidine nucleoside phosphorylase (PYNP) catalyzes the reversible phosphorolysis of pyrimidines in the nucleotide-synthesis salvage pathway. In order to study the structure–thermostability relationship of this enzyme, PYNP from the extreme thermophile Thermus thermophilus HB8 (TTHA1771) has been cloned, overexpressed and purified. The TTHA1771 protein was crystallized at 291 K using the oil-microbatch method with PEG 4000 as a precipitant. A native data set was collected to 1.8 Å resolution using synchrotron radiation. The crystal belongs to the monoclinic space group P2 1 , with unit-cell parameters a = 58.83, b = 76.23, c = 103.86 Å, β = 91.3°

  13. 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

  14. 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

  15. 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.

  16. 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 ...

  17. 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...

  18. 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...

  19. 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.

  20. In silico analysis of the three-dimensional structures of the homodimer of uridine phosphorylase from Yersinia Pseudotuberculosis in the ligand-free state and in a complex with 5-fluorouracil

    Energy Technology Data Exchange (ETDEWEB)

    Lashkov, A. A., E-mail: alashkov83@gmail.com; Sotnichenko, S. E.; Mikhailov, A. M. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2013-03-15

    Pseudotuberculosis is an acute infectious disease characterized by a lesion of the gastrointestinal tract. A positive therapeutic effect can be achieved by selectively suppressing the activity of uridine phosphorylase from the causative agent of the disease Yersinia pseudotuberculosis. The synergistic effect of a combination of the chemotherapeutic agent 5-fluorouracil and antimicrobial drugs, which block the synthesis of pyrimidine bases, on the cells of pathogenic protozoa and bacteria is described in the literature. The three-dimensional structures of uridine phosphorylase from Yersinia pseudotuberculosis (YptUPh) both in the ligand-free state and in complexes with pharmacological agents are unknown, which hinders the search for and design of selective inhibitors of YptUPh. The three-dimensional structure of the ligand-free homodimer of YptUPh was determined by homology-based molecular modeling. The three-dimensional structure of the subunit of the YptUPh molecule belongs to {alpha}/{beta} proteins, and its topology is a three-layer {alpha}/{beta}/{alpha} sandwich. The subunit monomer of the YptUPh molecule consists of 38% helices and 24% {beta} strands. A model of the homodimer structure of YptUPh in a complex with 5-FU was obtained by the molecular docking. The position of 5-FU in the active site of the molecule is very consistent with the known data on the X-ray diffraction structures of other bacterial uridine phosphorylases (the complex of uridine phosphorylase from Salmonella typhimurium (StUPh) with 5-FU, ID PDB: 4E1V and the complex of uridine phosphorylase from Escherichia coli (EcUPh) with 5-FU and ribose 1-phosphate, ID PDB: 1RXC).

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Relative mRNA expression of prostate-derived E-twenty-six factor and E-twenty-six variant 4 transcription factors, and of uridine phosphorylase-1 and thymidine phosphorylase enzymes, in benign and malignant prostatic tissue

    Science.gov (United States)

    CAVAZZOLA, LUCIANE ROSTIROLA; CARVALHAL, GUSTAVO FRANCO; DEVES, CANDIDA; RENCK, DAIANA; ALMEIDA, RICARDO; SANTOS, DIóGENES SANTIAGO

    2015-01-01

    Prostate cancer is the most frequent urological tumor, and the second most common cancer diagnosed in men. Incidence and mortality are variable and appear to depend on behavioral factors and genetic predisposition. The prostate-derived E-twenty-six factor (PDEF) and E-twenty-six variant 4 (ETV4) transcription factors, and the thymidine phosphorylase (TP) and uridine phosphorylase-1 (UP-1) enzymes, are reported to be components of the pathways leading to tumorigenesis and/or metastasis in a number of tumors. The present study aimed to analyze the mRNA expression levels of these proteins in prostatic cancerous and benign tissue, and their association with clinical and pathological variables. Using quantitative reverse transcription polymerase chain reaction, the mRNA expression levels of PDEF, ETV4, TP and UP-1 were studied in 52 tissue samples (31 of benign prostatic hyperplasia and 21 of prostate adenocarcinomas) obtained from patients treated by transurethral resection of the prostate or by radical prostatectomy. Relative expression was assessed using the ∆-CT method. Data was analyzed using Spearman's tests for correlation. Pbenign and malignant prostatic tissues. Further studies are necessary to define the role of these proteins as therapeutic targets in prostate cancer. PMID:26137165

  6. 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.

  7. 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...

  8. 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 .

  9. 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.

  10. 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.

  11. 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.

  12. 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 ...

  13. 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...

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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.

  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. 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.

  3. 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.

  4. 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...

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Efficient one-pot enzymatic synthesis of alpha-(1 -> 4)-glucosidic disaccharides through a coupled reaction catalysed by Lactobacillus acidophilus NCFM maltose phosphorylase

    DEFF Research Database (Denmark)

    Nakai, Hiroyuki; Dilokpimol, Adiphol; Abou Hachem, Maher

    2010-01-01

    Lactobacillus acidophilus NCFM maltose phosphorylase (LaMalP) of glycoside hydrolase family 65 catalysed enzymatic synthesis of alpha-(1 -> 4)-glucostdic disacchandes from maltose and five monosacchandes in a coupled phosphorolysis/reverse phosphorolysis one-pot reaction Thus phosphorolysis...

  12. 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)

  13. 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...

  14. 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

  15. 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.

  16. 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

  17. 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

  18. Toxoplasma gondii Requires Glycogen Phosphorylase for Balancing Amylopectin Storage and for Efficient Production of Brain Cysts.

    Science.gov (United States)

    Sugi, Tatsuki; Tu, Vincent; Ma, Yanfen; Tomita, Tadakimi; Weiss, Louis M

    2017-08-29

    involved in amylopectin storage and utilization. IMPORTANCE Toxoplasma gondii is an obligate intracellular parasite that causes disease in immune-suppressed individuals, as well as a fetopathy in pregnant women who acquire infection for the first time during pregnancy. This parasite can differentiate between tachyzoites (seen in acute infection) and bradyzoites (seen in latent infection), and this differentiation is associated with disease relapse. A characteristic of bradyzoites is that they contain cytoplasmic amylopectin granules. The regulatory mechanisms and the roles of amylopectin granules during latent infection remain to be elucidated. We have identified a role of T. gondii glycogen phosphorylase (TgGP) in the regulation of starch digestion and a role of posttranslational modification of TgGP, i.e., phosphorylation of Ser25, in the regulation of amylopectin digestion. By manipulating TgGP activity in the parasite with genome editing, we found that the digestion and storage of amylopectin due to TgGP activity are both important for latency in the brain. Copyright © 2017 Sugi et al.

  19. 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.

  20. 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 '

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

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

    Science.gov (United States)

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

    2016-05-01

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

  8. 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.

  9. 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...

  10. 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.

  11. 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.

  12. 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.).

  13. 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 ...

  14. ( 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 ...

  15. 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.

  16. Compositions and methods involving methyladenosine phosphorylase in the diagnosis and treatment of proliferative disorders

    Science.gov (United States)

    Olopade, Olufunmilayo I.

    2007-03-20

    Disclosed are novel nucleic acid and peptide compositions comprising methylthioadenosine phosphorylase (MTAP) and methods of use for MTAP amino acid sequences and DNA segments comprising MTAP in the diagnosis of human cancers and development of MTAP-specific antibodies. Also disclosed are methods for the diagnosis and treatment of tumors and other proliferative cell disorders, and identification of tumor suppressor genes and gene products from the human 9p21-p22 chromosome region. Such methods are useful in the diagnosis of multiple tumor types such as bladder cancer, lung cancer, breast cancer, pancreatic cancer, brain tumors, lymphomas, gliomas, melanomas, and leukemias.

  17. Inhibition of human thymidine phosphorylase by conformationally constrained pyrimidine nucleoside phosphonic acids and their "open-structure" isosteres

    Czech Academy of Sciences Publication Activity Database

    Kóšiová, Ivana; Šimák, Ondřej; Panova, Natalya; Buděšínský, Miloš; Petrová, Magdalena; Rejman, Dominik; Liboska, Radek; Páv, Ondřej; Rosenberg, Ivan

    2014-01-01

    Roč. 74, Mar 3 (2014), s. 145-168 ISSN 0223-5234 R&D Projects: GA ČR GA203/09/0820; GA ČR GA202/09/0193; GA ČR GA13-24880S; GA ČR GA13-26526S Institutional support: RVO:61388963 Keywords : phosphonate * conformationally constrained nucleotide analog * human thymidine phosphorylase * PBMC * bi-substrate-like inhibitor * Michael addition Subject RIV: CC - Organic Chemistry Impact factor: 3.447, year: 2014

  18. 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)

  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. 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...

  1. Effect of combined gamma-irradiation and storage on biochemical changes in sweet potato

    International Nuclear Information System (INIS)

    Ajlouni, S.; Hamdy, M.K.

    1988-01-01

    Sucrose of uncured Red Jewel sweet potato increased from 3.8% to 10.7% after a combined treatment of a 300 Krad dose ( 60 Co) and 4 days storage at 24 0 C post-irradiation (PI). Starch decreased from 16.8% to 6.1% after 16 days following a 500 Krad treatment. Phosphorylase, phosphoglucomutase and sucrose phosphate synthase enzyme specific activities increase 2.4-, 1.8- and 1.3-fold, respectively, after 3 days PI following 200 Krad exposures compared to nonirradiated roots. The beta-Amylase, phosphoglucose isomerase and sucrose synthase specific activities increased 1.2-fold. Sucrose synthesis in the irradiated sweet potato was attributed to beta-amylase, phosphorylase, phosphoglucomutase, phosphoglucose isomerase and sucrose synthase

  2. 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.

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

    Science.gov (United States)

    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.

  4. 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...

  5. 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)

  6. 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.

  7. 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.

  8. 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

  9. 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....

  10. 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.

  11. 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

  12. 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

  13. 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....

  14. Is muscle glycogenolysis impaired in X-linked phosphorylase b kinase deficiency?

    DEFF Research Database (Denmark)

    Orngreen, M.C.; Schelhaas, H.J.; Jeppesen, T.D.

    2008-01-01

    OBJECTIVE: It is unclear to what extent muscle phosphorylase b kinase (PHK) deficiency is associated with exercise-related symptoms and impaired muscle metabolism, because 1) only four patients have been characterized at the molecular level, 2) reported symptoms have been nonspecific, and 3......) lactate responses to ischemic handgrip exercise have been normal. METHODS: We studied a 50-year-old man with X-linked PHK deficiency using ischemic forearm and cycle ergometry exercise tests to define the derangement of muscle metabolism. We compared our findings with those in patients with Mc...... in healthy subjects. Constant workload elicited a second wind in all patients with McArdle disease, but not in the patient with PHK deficiency. IV glucose administration appeared to improve exercise tolerance in the patient with PHK deficiency, but not to the same extent as in the patients with Mc...

  15. 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.

  16. 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.

  17. 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)

  18. 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.

  19. 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.

  20. 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.

  1. 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 ...

  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. 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...

  4. 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.

  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. 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)

  7. 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)

  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. 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...

  10. 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 ...

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

    Science.gov (United States)

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

    2013-03-01

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

  12. The maltodextrin transport system and metabolism in Lactobacillus acidophilus NCFM and production of novel alpha-glucosides through reverse phosphorolysis by maltose phosphorylase

    DEFF Research Database (Denmark)

    Nakai, Hiroyuki; Baumann, Martin; Petersen, B.O.

    2009-01-01

    regulator of the LacI-GalR family. Enzymatic properties are described for recombinant maltose phosphorylase (MalP) of glycoside hydrolase family 65 (GH65), which is encoded by malP (GenBank: AAV43670.1) of this gene cluster and produced in Escherichia coli. MalP catalyses phosphorolysis of maltose...

  13. 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.

  14. Methylthioadenosine phosphorylase compositions and methods of use in the diagnosis and treatment of proliferative disorders

    Science.gov (United States)

    Olopade, Olufunmilayo I.

    2005-03-22

    Disclosed are novel nucleic acid and peptide compositions comprising methythlioadenosine phosphorylase (MTAP) and methods of use for MTAP amino acid sequences and DNA segments comprising MTAP in the diagnosis of human cancers and development of MTAP-specific antibodies. Also disclosed are methods for the diagnosis and treatment of tumors and other proliferative cell disorders, and idenification tumor suppressor genes and gene products from the human 9p21-p22 chromosome region. Such methods are useful in the diagnosis of multiple tumor types such as bladder cancer, lung cancer, breast cancer, pancreatic cancer, brain tumors, lymphomas, gliomas, melanomas, and leukemias.

  15. A thermal after-effect of UV irradiation of muscle glycogen phosphorylase b.

    Directory of Open Access Journals (Sweden)

    Valeriya V Mikhaylova

    Full Text Available Different test systems are used to characterize the anti-aggregation efficiency of molecular chaperone proteins and of low-molecular-weight chemical chaperones. Test systems based on aggregation of UV-irradiated protein are of special interest because they allow studying the protective action of different agents at physiological temperatures. The kinetics of UV-irradiated glycogen phosphorylase b (UV-Phb from rabbit skeletal muscle was studied at 37°C using dynamic light scattering in a wide range of protein concentrations. It has been shown that the order of aggregation with respect to the protein is equal to unity. A conclusion has been made that the rate-limiting stage of the overall process of aggregation is heat-induced structural reorganization of a UV-Phb molecule, which contains concealed damage.

  16. 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.

  17. 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...

  18. 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

  19. 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

  20. 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...

  1. 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.

  2. 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...

  3. 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....

  4. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  7. Effect of combined gamma-irradiation and storage on biochemical changes in sweet potato

    International Nuclear Information System (INIS)

    Ajlouni, S.; Handy, M.K.

    1992-01-01

    Sucrose of uncured red jewel sweet potato increased from 3.8% to 10.7% after a combined treatment of a 300 Krad dose and 4 days storage at 24 C o post-irradiation (PI). Starch decreased from 16.8% to 6.1% after 16 days following a 500 Krad treatment. Phosphorylase, phosphoglucomutase and sucrose phosphate synthase enzyme specific activities increased 2.4-, 1.8- and 1.3-fold, respectively, after 3 days PI following 200 Krad exposures compared to nonirradiated roots. The beta-Amylase, phospho glucose isomerase and sucrose synthase specific activities increased 1.2-fold. Sucrose synthesis in the irradiated sweet potato was attributed to beta-amylase, phosphorylase, phosphoglucomutase, phospho glucose isomerase and sucrose synthase. (author). 28 refs., 3 figs., 2 tabs

  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. 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:.

  11. 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.

  12. 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.

  13. 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.

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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

  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. 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

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

    Science.gov (United States)

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

    2014-01-01

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

  3. 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.

  4. 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.

  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. Thermal treatment of starch slurry in Couette-Taylor flow apparatus

    Directory of Open Access Journals (Sweden)

    Hubacz Robert

    2017-09-01

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

  7. 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.

  8. 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.

  9. 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

  10. Starch digestibility and predicted glycemic index of fried sweet potato cultivars

    Directory of Open Access Journals (Sweden)

    Amaka Odenigbo

    2012-07-01

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

  11. Biocatalytic Process for Production of α-Glucosylglycerol Using Sucrose Phosphorylase

    Directory of Open Access Journals (Sweden)

    Christiane Luley-Goedl

    2010-01-01

    Full Text Available Glycosylglycerols are powerful osmolytes, produced by various plants, algae and bacteria in adaptation to salt stress and drought. Among them, glucosylglycerol (2-O-α-D-glucopyranosyl-sn-glycerol; GG has attracted special attention for its promising application as a moisturizing agent in cosmetics. A biocatalytic process for the synthesis of GG as industrial fine chemical is described in which sucrose phosphorylase (from Leuconostoc mesenteroides catalyzes regioselective glucosylation of glycerol using sucrose as the donor substrate. The overall enzymatic conversion, therefore, is sucrose+glycerol→GG+D-fructose. Using a twofold molar excess of glycerol acceptor in highly concentrated substrate solution, GG yield was 90 % based on ≥250 g/L of converted sucrose. Enzymatic GG production was implemented on a multihundred kg-per-year manufacturing scale, and a commercial product for cosmetic applications is distributed on the market under the name Glycoin®. Technical features of the biotransformation that were decisive for a successful process development are elaborated. Stabilization of proteins is another interesting field of application for GG.

  12. 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)

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

    Science.gov (United States)

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

    2017-06-01

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

  14. 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.

  15. 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

  16. Escherichia coli Purine Nucleoside Phosphorylase II, the Product of the xapA Gene

    DEFF Research Database (Denmark)

    Dandanell, Gert; Szczepanowski, R.H.; Kierdaszuk, B.

    2005-01-01

    the monoanionic form of xanthine. A single amino acid exchange, tyrosine 191 to leucine, is sufficient to convert E. coli PNP-II into an enzyme with the specificity of conventional trimeric PNPs, but the reciprocal mutation in human PNP, valine 195 to tyrosine, does not elicit xanthosine phosphorylase activity...... forms, PNP-II trimers dimerize, leading to a subunit arrangement that is qualitatively different from the "trimer of dimers" arrangement of conventional high molecular mass PNPs. Crystal structures are compatible with similar binding modes for guanine and xanthine, with a preference for the neutral over...

  17. 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.

  18. 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)

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

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

    Science.gov (United States)

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

    2018-01-01

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

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

    Science.gov (United States)

    Fang, Qi

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

  6. 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

  7. 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.

  8. 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.

  9. Rheological Properties and Electrospinnability of High-Amylose Starch in Formic Acid.

    Science.gov (United States)

    Lancuški, Anica; Vasilyev, Gleb; Putaux, Jean-Luc; Zussman, Eyal

    2015-08-10

    Starch derivatives, such as starch-esters, are commonly used as alternatives to pure starch due to their enhanced mechanical properties. However, simple and efficient processing routes are still being sought out. In the present article, we report on a straightforward method for electrospinning high-amylose starch-formate nanofibers from 17 wt % aqueous formic acid (FA) dispersions. The diameter of the electrospun starch-formate fibers ranged from 80 to 300 nm. The electrospinnability window between starch gelatinization and phase separation was determined using optical microscopy and rheological studies. This window was shown to strongly depend on the water content in the FA dispersions. While pure FA rapidly gelatinized starch, yielding solutions suitable for electrospinning within a few hours at room temperature, the presence of water (80 and 90 vol % FA) significantly delayed gelatinization and dissolution, which deteriorated fiber quality. A complete destabilization of the electrospinning process was observed in 70 vol % FA dispersions. Optical micrographs showed that FA induced a disruption of starch granule with a loss of crystallinity confirmed by X-ray diffraction. As a result, starch fiber mats exhibited a higher elongation at break when compared to brittle starch films.

  10. Physical and mechanical properties of LDPE incorporated with different starch sources

    Science.gov (United States)

    Kormin, Shaharuddin; Kormin, Faridah; Dalour Hossen Beg, Mohammad; Bijarimi Mat Piah, Mohd

    2017-08-01

    In this study it was investigated the incorporation of different starches, such as sago starch, corn starch, potato starch, tapioca starch and wheat starch, in low-density polyethylene matrix (LDPE) to enhanced mechanical properties and to obtain partially biodegradable product with the aim to reduce the plastics wastes in the environment. For comparison, virgin LDPE, LDPE with different sources of starch blends were prepared and characterized under the same conditions. The starches were mixed to the LDPE using a twin screw extruder to guarantee the homogeneity of the formulations. The compound were shaping processed by injection moulding. The characterization of those compounds was done by physical (density, MFI), mechanical (Universal tensile machine). The addition of starch to LDPE reduced the MFI values, the tensile strength, elongation at break and impact strength, whereas the elastic modulus, flexural modulus and flexural strength increased. LDPE/SS show the good mechanical behavior compared to other formulation. The physical and mechanical properties were evident when 5 and 30 wt% were added. Water uptake increased with increased starch content and immersion time. The time taken for the composites to equilibrate was about one month even when they were immersed completely in water.

  11. 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.

  12. Effects of ruminally degradable starch levels on performance, nitrogen balance, and nutrient digestibility in dairy cows fed low corn-based starch diets

    Directory of Open Access Journals (Sweden)

    Guobin Luo

    2017-05-01

    Full Text Available Objective This trial was performed to examine the effects of ruminally degradable starch (RDS levels in total mixed ration (TMR with low corn-based starch on the milk production, whole-tract nutrient digestibility and nitrogen balance in dairy cows. Methods Eight multiparous Holstein cows (body weight [BW]: 717±63 kg; days in milk [DIM]: 169±29 were assigned to a crossover design with two dietary treatments: a diet containing 62.3% ruminally degradable starch (% of total starch, low RDS or 72.1% ruminally degradable starch (% of total starch, high RDS. Changes to the ruminally degradable levels were conducted by using either finely ground corn or steam-flaked corn as the starch component. Results The results showed that dry matter intake, milk yield and composition in dairy cows were not affected by dietary treatments. The concentration of milk urea nitrogen was lower for cows fed high RDS TMR than low RDS TMR. The whole-tract apparent digestibility of neutral detergent fiber, acid detergent fiber and crude protein decreased, and that of starch increased for cows fed high RDS TMR over those fed low RDS TMR, with no dietary effect on the whole-tract apparent digestibility of dry matter and organic matter. The proportion of urinary N excretion in N intake was lower and that of fecal N excretion in N intake was higher for cows fed high RDS TMR than those fed low RDS TMR. The N secretion in milk and the retention of N were not influenced by the dietary treatments. Total purine derivative was similar in cows fed high RDS TMR and low RDS TMR. Consequently, estimated microbial N flow to the duodenum was similar in cows fed high RDS TMR and low RDS TMR. Conclusion Results of this study show that ruminally degradable starch levels can influence whole-tract nutrient digestibility and nitrogen balance in dairy cows fed low corn-based starch diets, with no influence on performance.

  13. Effects of Sorghum [Sorghum bicolor (L. Moench] Crude Extracts on Starch Digestibility, Estimated Glycemic Index (EGI, and Resistant Starch (RS Contents of Porridges

    Directory of Open Access Journals (Sweden)

    Dilek Lemlioglu-Austin

    2012-09-01

    Full Text Available Bran extracts (70% aqueous acetone of specialty sorghum varieties (tannin, black, and black with tannin were used to investigate the effects of sorghum phenolic compounds on starch digestibility, Estimated Glycemic Index (EGI, and Resistant Starch (RS of porridges made with normal corn starch, enzyme resistant high amylose corn starch, and ground whole sorghum flours. Porridges were cooked with bran extracts in a Rapid Visco-analyser (RVA. The cooking trials indicated that bran extracts of phenolic-rich sorghum varieties significantly reduced EGI, and increased RS contents of porridges. Thus, there could be potential health benefits associated with the incorporation of phenolic-rich sorghum bran extracts into foods to slow starch digestion and increase RS content.

  14. 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...

  15. First principles insight into the α-glucan structures of starch

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  16. 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.

  17. 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.

  18. Physicochemical, morphological, and rheological characterization of Xanthosoma robustum Lego-like starch.

    Science.gov (United States)

    Londoño-Restrepo, Sandra M; Rincón-Londoño, Natalia; Contreras-Padilla, Margarita; Acosta-Osorio, Andrés A; Bello-Pérez, Luis A; Lucas-Aguirre, Juan C; Quintero, Víctor D; Pineda-Gómez, Posidia; del Real-López, Alicia; Rodríguez-García, Mario E

    2014-04-01

    This work presents the physicochemical and pasting characterization of isolated mafafa starch and mafafa flour (Xanthosoma robustum). According to SEM images of mafafa starches in the tuber, these starches form Lego-like shaped structures with diameters between 8 and 35 μm conformed by several starch granules of wedge shape that range from 2 to 7 μm. The isolated mafafa starch is characterized by its low contents of protein, fat, and ash. The starch content in isolated starch was found to be 88.58% while the amylose content obtained was 35.43%. X-ray diffraction studies confirm that isolated starch is composed mainly by amylopectin. These results were confirmed by differential scanning calorimetry and thermo gravimetric analysis. This is the first report of the molecular parameters for mafafa starch: molar mass that ranged between 2×10(8) and 4×10(8) g/mol, size (Rg) value between 279 and 295 nm, and molecular density value between 9.2 and 9.7 g/(mol nm(3)). This study indicates that mafafa starch shows long chains of amylopectin this fact contributes to higher viscosity development and higher gel stability. The obtained gel phase is transparent in the UV-vis region. The viscosity, gel stability and optical properties suggest that there is potential for mafafa starch applications in the food industry. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. 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.

  20. 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)

  1. Determination of the thermo-mechanical properties in starch and starch/gluten systems at low moisture content - a comparison of DSC and TMA.

    Science.gov (United States)

    Homer, Stephen; Kelly, Michael; Day, Li

    2014-08-08

    The impact of heating rate on the glass transition (Tg) and melting transitions observed by differential scanning calorimetry (DSC) on starch and a starch/gluten blend (80:20 ratio) at low moisture content was examined. The results were compared to those determined by thermo-mechanical analysis (TMA). Comparison with dynamic mechanical thermal analysis (DMTA) and phase transition analysis (PTA) is also discussed. Higher heating rates increased the determined Tg as well as the melting peak temperatures in both starch and the starch/gluten blend. A heating rate of 5°C/min gave the most precise value of Tg while still being clearly observed above the baseline. Tg values determined from the first and second DSC scans were found to differ significantly and retrogradation of starch biopolymers may be responsible. Tg values of starch determined by TMA showed good agreement with DSC results where the Tg was below 80°C. However, moisture loss led to inaccurate Tg determination for TMA analyses at temperatures above 80°C. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Dynamic moisture sorption characteristics of enzyme-resistant recrystallized cassava starch.

    Science.gov (United States)

    Mutungi, Christopher; Schuldt, Stefan; Onyango, Calvin; Schneider, Yvonne; Jaros, Doris; Rohm, Harald

    2011-03-14

    The interaction of moisture with enzyme-resistant recrystallized starch, prepared by heat-moisture treatment of debranched acid-modified or debranched non-acid-modified cassava starch, was investigated in comparison with the native granules. Crystallinities of the powdered products were estimated by X-ray diffraction. Moisture sorption was determined using dynamic vapor sorption analyzer and data fitted to various models. Percent crystallinities of native starch (NS), non-acid-modified recrystallized starch (NAMRS), and acid-modified recrystallized starch (AMRS) were 39.7, 51.9, and 56.1%, respectively. In a(w) below 0.8, sorption decreased in the order NS > NAMRS > AMRS in line with increasing sample crystallinities but did not follow this crystallinity dependence at higher a(w) because of condensation and polymer dissolution effects. Adsorbed moisture became internally absorbed in NS but not in NAMRS and AMRS, which might explain the high resistance of the recrystallized starches to digestion because enzyme and starch cannot approach each other over fairly sufficient surface at the molecular level.

  3. 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.

  4. Structural and functional properties of alkali-treated high-amylose rice starch.

    Science.gov (United States)

    Cai, Jinwen; Yang, Yang; Man, Jianmin; Huang, Jun; Wang, Zhifeng; Zhang, Changquan; Gu, Minghong; Liu, Qiaoquan; Wei, Cunxu

    2014-02-15

    Native starches were isolated from mature grains of high-amylose transgenic rice TRS and its wild-type rice TQ and treated with 0.1% and 0.4% NaOH for 7 and 14 days at 35 °C. Alkali-treated starches were characterised for structural and functional properties using various physical methods. The 0.1% NaOH treatment had no significant effect on structural and functional properties of starches except that it markedly increased the hydrolysis of starch by amylolytic enzymes. The 0.4% NaOH treatment resulted in some changes in structural and functional properties of starches. The alkali treatment affected granule morphology and decreased the electron density between crystalline and amorphous lamellae of starch. The effect of alkali on the crystalline structure including long- and short-range ordered structure was not pronounced. Compared with control starch, alkali-treated TRS starches had lower amylose content, higher onset and peak gelatinisation temperatures, and faster hydrolysis of starch by HCl and amylolytic enzymes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Cereal bioengineering: Amylopectin-free and hyper-phosphorylated barley starch

    DEFF Research Database (Denmark)

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

    Barley lines producing grains with either amylopectin-free or hyper-phosphorylated starches were made by transgenic methods. Cereals producing these kind of starches have not been reported before. Amylopectin-free barley was generated by simultaneously silencing the three genes encoding the starch...... and T1) of transgenic grains was tenfold higher than from vector control and wild type grains. Amylose content was not affected in hyper-phosphorylated grains. Hyper-phosphorylated starch granules had several pores on the surfaces, similar to pores seen on enzymatically semi-degraded granules...

  6. Cereal bioengineering: Amylopectin-free and hyper-phosphorylated barley starch

    DEFF Research Database (Denmark)

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

    2011-01-01

    Barley lines producing grains with either amylopectin-free or hyper-phosphorylated starches were made by transgenic methods. Cereals producing these kind of starches have not been reported before. Amylopectin-free barley was generated by simultaneously silencing the three genes encoding the starch...... and T1) of transgenic grains was tenfold higher than from vector control and wild type grains. Amylose content was not affected in hyper-phosphorylated grains. Hyper-phosphorylated starch granules had several pores on the surfaces, similar to pores seen on enzymatically semi-degraded granules...

  7. 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...

  8. 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

  9. 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.

  10. Effects of single and dual physical modifications on pinhão starch.

    Science.gov (United States)

    Pinto, Vânia Zanella; Vanier, Nathan Levien; Deon, Vinicius Gonçalves; Moomand, Khalid; El Halal, Shanise Lisie Mello; Zavareze, Elessandra da Rosa; Lim, Loong-Tak; Dias, Alvaro Renato Guerra

    2015-11-15

    Pinhão starch was modified by annealing (ANN), heat-moisture (HMT) or sonication (SNT) treatments. The starch was also modified by a combination of these treatments (ANN-HMT, ANN-SNT, HMT-ANN, HMT-SNT, SNT-ANN, SNT-HMT). Whole starch and debranched starch fractions were analyzed by gel-permeation chromatography. Moreover, crystallinity, morphology, swelling power, solubility, pasting and gelatinization characteristics were evaluated. Native and single ANN and SNT-treated starches exhibited a CA-type crystalline structure while other modified starches showed an A-type structure. The relative crystallinity increased in ANN-treated starches and decreased in single HMT- and SNT-treated starches. The ANN, HMT and SNT did not provide visible cracks, notches or grooves to pinhão starch granule. SNT applied as second treatment was able to increase the peak viscosity of single ANN- and HMT-treated starches. HMT used alone or in dual modifications promoted the strongest effect on gelatinization temperatures and enthalpy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Structural properties and digestibility of pulsed electric field treated waxy rice starch.

    Science.gov (United States)

    Zeng, Feng; Gao, Qun-Yu; Han, Zhong; Zeng, Xin-An; Yu, Shu-Juan

    2016-03-01

    Waxy rice starch was subjected to pulsed electric field (PEF) treatment at intensity of 30, 40 and 50kVcm(-1). The impact of PEF treatment on the granular morphology, molecular weight, semi-crystalline structure, thermal properties, and digestibility were investigated. The micrographs suggested that electric energy could act on the granule structure of starch granule, especially at high intensity of 50kVcm(-1). Gelatinization onset temperature, peak temperature, conclusion temperature and enthalpy value of PEF treated starches were lower than that of native starch. The 9nm lamellar peak of PEF treated starches decreased as revealed by small angle X-ray scattering. The relative crystallinity of treated starches decreased as the increase of electric field intensity. Increased rapidly digestible starch level and decreased slowly digestible starch level was found on PEF treated starches. These results would imply that PEF treatment induced structural changes in waxy rice starch significantly affected its digestibility. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Studies on gamma-irradiation of high amylose corn starch, 1

    International Nuclear Information System (INIS)

    Watanabe, Yukio; Ayano, Yuko; Obara, Tetsujiro.

    1976-01-01

    Amylomaize 7, amylomaize 5, normal corn, waxy corn and potato starches were irradiated with 60 Co-gamma rays at the dose levels from 2x10 4 to 100x10 4 rad to determine the changes in physicochemical properties by irradiation. Irradiated starches were characterized by determination of amylography, specific viscosity, blue value, pH, acidity, carbonyl content, reducing value and limit of β-amylolysis. Irradiated starches showed a decrease in viscosity and blue value, and an increase in reducing value with increasing dose levels. These results were seemed to indicate the degradation of starch molecule. A slight oxidation of starch was suggested by a decrease in pH and an increase in acidity and carbonyl content. Amylomaize 7 and amylomaize 5 starches were less sensitive than the other starches in terms of irradiation effects. The rheological properties determined by amylography and Ostwald viscometer changed at the lowest dose (5x10 4 rad) and the other properties changed above 20x10 4 rad. The limits of β-amylase hydrolysis of normal corn, waxy corn and potato starches increased slightly by irradiation (100x10 4 rad). On the other hand, β-amylolysis limits of amylomaize 7 and amylomaize 5 starches were lower about 5.5% and 2.5% respectively than that of nonirradiated samples. The decrease of β-amylolysis limit enlarged with increasing amylose content. (auth.)

  13. 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)

  14. A quantitative histochemical procedure for the demonstration of purine nucleoside phosphorylase activity in rat and human liver using Tetranitro BT and xanthine oxidase as auxiliary enzyme

    NARCIS (Netherlands)

    Frederiks, W. M.; Bosch, K. S.; van Gulik, T.

    1993-01-01

    A quantitative histochemical procedure was developed for the demonstration of purine nucleoside phosphorylase in rat liver using unfixed cryostat sections and the auxiliary enzyme xanthine oxidase. The optimum incubation medium contained 18% (w/v) poly(vinyl alcohol), 100 mM phosphate buffer, pH

  15. Reactive compatibilization of ethylene-co-vinyl acetate/starch blends

    NARCIS (Netherlands)

    Ma, P.; Hristova - Bogaerds, D.G.; Schmit, P.; Goossens, J.G.P.; Lemstra, P.J.

    2012-01-01

    The dispersion of starch as a filler in hydrophobic ethylene-co-vinyl acetate (EVA) rubber is an issue. To obtain a fine dispersion of starch in EVA rubber, EVA/starch blends were prepared by reactive extrusion in the pres- ence of maleic anhydride (MA), benzoyl peroxide (BPO), and glycerol. MA,

  16. 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...

  17. 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.

  18. Preparation of calcium- and magnesium-fortified potato starches with altered pasting properties.

    Science.gov (United States)

    Noda, Takahiro; Takigawa, Shigenobu; Matsuura-Endo, Chie; Ishiguro, Koji; Nagasawa, Koichi; Jinno, Masahiro

    2014-09-15

    Calcium- and magnesium-fortified potato starches were prepared by immersion in various concentrations of CaCl2 and MgCl2 aqueous solutions, respectively. The pasting properties, i.e., peak viscosity and breakdown, of all the starches obtained above were analyzed using a Rapid Visco Analyzer. Furthermore, the gelatinization properties and in vitro digestibility of the representative calcium- and magnesium-fortified starches were tested. The maximum calcium content of the fortified potato starches was as high as 686 ppm with the addition of a high-concentration CaCl2 solution, while the calcium content of the control potato starch was 99 ppm. The magnesium content increased from 89 to 421 ppm by treatment of the potato starch with an MgCl2 solution. Markedly lower values of peak viscosity and breakdown were observed in calcium- and magnesium-fortified potato starches than in the control potato starch. However, the gelatinization temperature and enthalpy as well as resistant starch content of calcium- and magnesium-fortified potato starches were similar to those of the control potato starch. It is concluded that potato starches with altered pasting properties can be easily manufactured by the use of solutions containing high levels of calcium and magnesium.

  19. 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

  20. 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.

  1. 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.

  2. Effect of magnetic starch on the clarification of hematite tailings wastewater

    Science.gov (United States)

    Yue, Tao; Wu, Xiqing

    2018-02-01

    The magnetic starch solution, synthesized by mixing the caustic starch, the Fe2+ solution (in some cases containing the Zn2+, Cu2+, Mn2+ or Mg2+ ions) and H2O2 solution, was used as the flocculant to investigate its clarification effect on hematite tailings wastewater. Based on the clarification tests and adsorption analysis it was demonstrated that the magnetic starch produced better clarification effect than the caustic starch, and the adsorption of magnetic starch onto hematite tailings particles was also stronger than the caustic starch. AFM found that the magnetic interaction between magnetic seeds and hematite is characteristic of long range force and greatly strengthens the adsorption of magnetic seeds onto fine hematite for agglomeration. FTIR indicates the starch adsorbed onto the surfaces of hematite and magnetic seeds, thus acting as the bridging between hematite particles and magnetic seeds, resulting in an intensified coverage of the starch onto hematite and positive action in the clarification.

  3. Comparison of various types of starch when used in meat sausages.

    Science.gov (United States)

    Skrede, G

    1989-01-01

    Technological and sensory properties of meat sausages formulated with 4·0% of either potato flour, modified (acetylated distarch phosphate) potato starch, wheat, corn or tapioca starch were compared. Sausages were analyzed after cooking at temperatures between 65 and 85°C followed by storage at 5°C and -25°C. Characteristics evaluated were weight loss during cooking and storage, instrumentally and sensory assessed firmness, taste and smell of sausages. The results revealed differences in the suitability of starches for use in meat sausages. Part of the differences could be ascribed to differences in gelatination properties of the starches. With the criteria used for evaluating quality, potato flour was rated as the best suited starch followed by wheat starch while tapioca was rated as the least suited. Corn starch required cooking temperatures above 75°C and showed relatively low freeze/thaw stability. The modified potato starch stored well both above and below the freezing point. Copyright © 1989. Published by Elsevier Ltd.

  4. Effect of acid hydrolysis on starch structure and functionality: a review.

    Science.gov (United States)

    Wang, Shujun; Copeland, Les

    2015-01-01

    Acid hydrolysis is an important chemical modification that can significantly change the structural and functional properties of starch without disrupting its granular morphology. A deep understanding of the effect of acid hydrolysis on starch structure and functionality is of great importance for starch scientific research and its industrial applications. During acid hydrolysis, amorphous regions are hydrolyzed preferentially, which enhances the crystallinity and double helical content of acid hydrolyzed starch. This review discusses current understanding of the effect of acid hydrolysis on starch structure and functionality. The effects of acid hydrolysis on amylose content, chain length distribution of amylopectin molecules, molecular and crystalline organization (including lamellar structure) and granular morphology are considered. Functional properties discussed include swelling power, gelatinization, retrogradation, pasting, gel texture, and in vitro enzyme digestibility. The paper also highlights some promising applications of acid hydrolyzed starch (starch nanocrystals) in the preparation of biodegradable nanocomposites, bio-hydrogen, and slowly digestible starch-based healthy foods.

  5. 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.

  6. Change in digestibility of gamma-irradiated starch by low temperature cooking

    International Nuclear Information System (INIS)

    Kume, T.; Ishigaki, I.; Rahman, S.

    1988-01-01

    Combination effect of irradiation and low temperature cooking on starch digestibility has been investigated as a basic research for application of radiosterilization on starch fermentation. The digestion of corn starch by glucoamylase after cooking at low temperature was enhanced by γ-irradiation and the required cooking temperature was decreased from 75-80 0 C to 65 0 C by 25 kGy. Gelatinization of starches except tapioca starch was enhanced by irradiation and it corresponds to the digestibility. The digestibility of potato starch which has a high viscosity was especially enhanced at low temperature cooking because the viscosity was markedly decreased by irradiation. These results show that the irradiation of starches is useful not only for the sterilization of fermentation broth but also for the enhancement of digestion. (orig.) [de

  7. Change in digestibility of gamma-irradiated starch by low temperature cooking

    Energy Technology Data Exchange (ETDEWEB)

    Kume, T.; Ishigaki, I.; Rahman, S.

    1988-04-01

    Combination effect of irradiation and low temperature cooking on starch digestibility has been investigated as a basic research for application of radiosterilization on starch fermentation. The digestion of corn starch by glucoamylase after cooking at low temperature was enhanced by ..gamma..-irradiation and the required cooking temperature was decreased from 75-80/sup 0/C to 65/sup 0/C by 25 kGy. Gelatinization of starches except tapioca starch was enhanced by irradiation and it corresponds to the digestibility. The digestibility of potato starch which has a high viscosity was especially enhanced at low temperature cooking because the viscosity was markedly decreased by irradiation. These results show that the irradiation of starches is useful not only for the sterilization of fermentation broth but also for the enhancement of digestion.

  8. 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...

  9. 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...

  10. Fabrication and characterization of size-controlled starch-based nanoparticles as hydrophobic drug carriers.

    Science.gov (United States)

    Han, Fei; Gao, Chunmei; Liu, Mingzhu

    2013-10-01

    Acetylated corn starch was successfully synthesized and optimized by the reaction of native corn starch with acetic anhydride and acetic acid in the presence of sulfuric acid as a catalyst. The optimal degree of substitution of 2.85 was obtained. Starch-based nanoparticles were fabricated by a simple and novel nanoprecipitation procedure, by the dropwise addition of water to acetone solution of acetylated starch under stirring. Fourier transform infrared spectrometry showed that acetylated starch had some new bands at 1750, 1375 and 1240 cm(-1) while acetylated starch nanoparticles presented the identical peaks as the drug-loaded acetylated starch nanoparticles and the acetylated starch. Wide angle X-ray diffraction indicated that A-type pattern of native starch was completely transformed into the V-type pattern of Acetylated starch and starch-based nanoparticles show the similar type pattern with the acetylated starch. The scanning electron microscopy showed that the different sizes of pores formed on the acetylated starch granules were utterly converted into the uniform-sized spherical nanoparticles after the nanoprecipitation. The encapsulation efficiency and diameter of nanoparticle can be adjusted by the degree of substitution, the volume ratio of nonsolvent to solvent and the weight ratio of acetylated starch to drug. It was also depicted that the release behaviors of drug-loaded nanoparticles depend on the size of nanoparticles and the degree of substitution of the acetylated starch. Release studies prove that the starch-based nanoparticles with uniform size can be used for the encapsulation of hydrophobic drug and attained the sustained and controllable drug release carriers.

  11. Preparation and Characterization of PLA-Starch Biodegradable Composites Via Radiation Processing

    Energy Technology Data Exchange (ETDEWEB)

    Hemvichian, K.; Suwanmala, P. [Thailand Institute of Nuclear Technology (TINT) (Thailand); Kungsumrith, W. [Department of Industrial Engineering, Faculty of Engineering, Thammasat University (TU) (Thailand); Pongprayoon, T. [Department of Chemical Engineering, Faculty of Engineering, King Mongkut’s University of Technology North Bangkok (KMUTNB), Bangkok (Thailand)

    2011-07-01

    This research project aims to apply the use of radiation processing to prepare biodegradable composites from poly(lactic acid) or polylactide (PLA) and cassava starch. Cassava starch, a natural polymer that is inexpensive and abundant, especially in Thailand, will be used as starting material. Functional group of cassava starch will be modified first in order to render starch more compatible with PLA. The monomer with desired functional groups will be grafted onto the backbone of starch via radiation-induced grafting polymerization. Different parameters will be examined to determine the optimum conditions for the grafting polymerization. The modified starch will subsequently be blended with PLA, with and without clay, to form biodegradable composites. In order to further improve the thermal properties, the blends and their composites will be subjected to radiation to induce crosslinking between the molecules of PLA and starch derivatives. (author)

  12. Preparation and Characterization of PLA-Starch Biodegradable Composites Via Radiation Processing

    International Nuclear Information System (INIS)

    Hemvichian, K.; Suwanmala, P.; Kungsumrith, W.; Pongprayoon, T.

    2011-01-01

    This research project aims to apply the use of radiation processing to prepare biodegradable composites from poly(lactic acid) or polylactide (PLA) and cassava starch. Cassava starch, a natural polymer that is inexpensive and abundant, especially in Thailand, will be used as starting material. Functional group of cassava starch will be modified first in order to render starch more compatible with PLA. The monomer with desired functional groups will be grafted onto the backbone of starch via radiation-induced grafting polymerization. Different parameters will be examined to determine the optimum conditions for the grafting polymerization. The modified starch will subsequently be blended with PLA, with and without clay, to form biodegradable composites. In order to further improve the thermal properties, the blends and their composites will be subjected to radiation to induce crosslinking between the molecules of PLA and starch derivatives. (author)

  13. Chemical, morphological, rheological and thermal properties of Solanum lycocarpum phosphorylated starches

    Directory of Open Access Journals (Sweden)

    Diego Palmiro Ramirez Ascheri

    2014-08-01

    Full Text Available The increasing need for starches with specific characteristics makes it important to study unconventional starches and their modifications in order to meet consumer demands. The aim of this work was to study physicochemical characteristics of native starch and phosphate starch of S. lycocarpum. Native starch was phosphated with sodium tripolyphosphate (5-11% added with stirring. Chemical composition, morphology, density, binding ability to cold water, swelling power and solubility index, turbidity and syneresis, rheological and calorimetric properties were determined. Phosphorus was not detected in the native sample, but the phosphating process produced modified starches with phosphorus contents of 0.015, 0.092 and 0.397%, with the capacity of absorbing more water, either cold or hot. Rheological data showed the strong influence of phosphorus content on viscosity of phosphate starch, with lower pasting temperature and peak viscosity higher than those of native starch. Enthalpy was negatively correlated with the phosphorus content, requiring 9.7; 8.5; 8.1 and 6.4 kJ g-1 of energy for the transition from the amorphous to the crystalline state for the starch granules with phosphorus contents of 0; 0.015; 0.092 and 0.397%, respectively. Cluster analysis and principal component analysis showed that starches with 0.015 and 0.092% phosphorus have similar characteristics and are different from the others. Our results show that the characteristics of phosphate modified S. lycocarpum starch have optimal conditions to meet the demands of raw materials, which require greater consistency in stickiness, combined with low rates of retrogradation and syneresis.

  14. All-natural bio-plastics using starch-betaglucan composites

    DEFF Research Database (Denmark)

    Sagnelli, Domenico; Kirkensgaard, Jacob Judas Kain; Giosafatto, Concetta Valeria L.

    2017-01-01

    functionalities chemical modifications or blending with synthetic polymers, such as polycaprolactone are required (e.g. Mater-Bi). As an alternative, all-natural and compostable bio-plastics can be produced by blending starch with other polysaccharides. In this study, we used a maize starch (ST) and an oat β...... BG content. Our data show that the blending of starch with other natural polysaccharides is a noteworthy path to improve the functionality of all-natural polysaccharide bio-plastics systems....

  15. 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.

  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. Thermal Behavior of Tacca leontopetaloides Starch-Based Biopolymer

    Directory of Open Access Journals (Sweden)

    Nurul Shuhada Mohd Makhtar

    2013-01-01

    Full Text Available Starch is used whenever there is a need for natural elastic properties combined with low cost of production. However, the hydrophilic properties in structural starch will decrease the thermal performance of formulated starch polymer. Therefore, the effect of glycerol, palm olein, and crude palm oil (CPO, as plasticizers, on the thermal behavior of Tacca leontopetaloides starch incorporated with natural rubber in biopolymer production was investigated in this paper. Four different formulations were performed and represented by TPE1, TPE2, TPE3, and TPE4. The compositions were produced by using two-roll mill compounding. The sheets obtained were cut into small sizes prior to thermal testing. The addition of glycerol shows higher enthalpy of diffusion in which made the material easily can be degraded, leaving to an amount of 6.6% of residue. Blending of CPO with starch (TPE3 had a higher thermal resistance towards high temperature up to 310°C and the thermal behavior of TPE2 only gave a moderate performance compared with other TPEs.

  18. Modification of Foamed Articles Based on Cassava Starch

    International Nuclear Information System (INIS)

    Ponce, P.

    2006-01-01

    This work reports the influence of radiation, plasticizers and poly vinyl alcohol (PVA) on the barrier properties [water vapour permeability (WVP)) and mechanical properties (tensile strength and elongation; compression resistance and flexibility) of foamed articles based on cassava starch. The starch foam was obtained by thermopressing process. Poly ethylene glycol (PEG, 300) was selected as plasticizer and water was necessary for the preparation of the foams. The foamed articles based on cassava starch were irradiated at low doses of 2 and 5 kGy, commonly used in food irradiation. The mechanical properties of starch foams are influenced by the plasticizer concentration and by irradiation dose. An increase in PEG content showed a considerable increase in elongation percentage and a decrease in the tensile strength of the foams; also increase the permeability of the foams in water. After irradiation, the barrier properties and mechanical properties of the foams were improved due to chemical reactions among polymer molecules. Irradiated starch cassava foams with poly vinyl alcohol (PVA) have good flexibility and low water permeability. WVP can be reduced by low doses of gamma radiation

  19. [Yield of starch extraction from plantain (Musa paradisiaca). Pilot plant study].

    Science.gov (United States)

    Flores-Gorosquera, Emigdia; García-Suárez, Francisco J; Flores-Huicochea, Emmanuel; Núñez-Santiago, María C; González-Soto, Rosalia A; Bello-Pérez, Luis A

    2004-01-01

    In México, the banana (Musa paradisiaca) is cooked (boiling or deep frying) before being eaten, but the consumption is not very popular and a big quantity of the product is lost after harvesting. The unripe plantain has a high level of starch and due to this the use of banana can be diversified as raw material for starch isolation. The objective of this work was to study the starch yield at pilot plant scale. Experiments at laboratory scale were carried out using the pulp with citric acid to 0,3 % (antioxidant), in order to evaluate the different unitary operations of the process. The starch yield, based on starch presence in the pulp that can be isolated, were between 76 and 86 %, and the values at pilot plant scale were between 63 and 71 %, in different lots of banana fruit. Starch yield values were similar among the diverse lots, showing that the process is reproducible. The lower values of starch recovery at pilot plant scale are due to the loss during sieving operations; however, the amount of starch recovery is good.

  20. Development and characterisation of composite films made of kefiran and starch.

    Science.gov (United States)

    Motedayen, Ali Akbar; Khodaiyan, Faramarz; Salehi, Esmail Atai

    2013-02-15

    In this study, new edible composite films were prepared by blending kefiran with corn starch. Film-forming solutions of different ratios of kefiran to corn starch (100/0, 70/30, 50/50, 30/70) were cast at room temperature. The effects of starch addition on the resulting films' physical, mechanical and water-vapor permeability (WVP) properties were investigated. Increasing starch content from 0% to 50% (v/v) decreased the WVP of films; however, with further starch addition the WVP increased. Also, this increase in starch content increased the tensile strength and extensibility of the composite films. However, these mechanical properties decreased at higher starch contents. Dynamic mechanical thermal analysis (DMTA) curves showed that addition of starch at all levels increased the glass transition temperature of films. The electron scanning micrograph for the composite film was homogeneous, without signs of phase separation between the components. Thus, it was observed that these two film-forming components were compatible, and that an interaction existed between them. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Interphase vs confinement in starch-clay bionanocomposites.

    Science.gov (United States)

    Coativy, Gildas; Chevigny, Chloé; Rolland-Sabaté, Agnès; Leroy, Eric; Lourdin, Denis

    2015-03-06

    Starch-clay bionanocomposites containing 1-10% of natural montmorillonite were elaborated by melt processing in the presence of water. A complex macromolecular dynamics behavior was observed: depending on the clay content, an increase of the glass transition temperature and/or the presence of two overlapped α relaxation peaks were detected. Thanks to a model allowing the prediction of the average interparticle distance, and its comparison with the average size of starch macromolecules, it was possible to associate these phenomena to different populations of macromolecules. In particular, it seems that for high clay content (10%), the slowdown of segmental relaxation due to confinement of the starch macromolecules between the clay tactoïds is the predominant phenomenon. While for lower clay contents (3-5%), a significant modification of chain relaxation seems to occur, due to the formation of an interphase by the starch macromolecules in the vicinity of clay nanoparticles coexisting with the bulk polymer. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. 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)

  3. 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)

  4. Application of extrusion-cooking for processing of thermoplastic starch (TPS)

    NARCIS (Netherlands)

    Moscicki, Leszek; Mitrus, Marcin; Wojtowicz, Agnieszka; Oniszczuk, Tomasz; Rejak, Andrzej; Janssen, Leon; Mościcki, Leszek

    Thermoplastic starch (TPS) as fully biodegradable biopolymer appeared to be one of the most useful and promising materials for packaging purpose. To obtain TPS thermal and mechanical processing should disrupt semi-crystalline starch granules. As the melting temperature of pure starch is

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

    OpenAIRE

    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 pre...

  6. Pd-catalyzed Suzuki-Miyaura coupling reaction in the synthesis of 5-aryl-1-[2-(phosphonomethoxy)ethyl]uracils as potential multisubstrate inhibitors of thymidine phosphorylase

    Czech Academy of Sciences Publication Activity Database

    Pomeisl, Karel; Holý, Antonín; Pohl, Radek

    2007-01-01

    Roč. 48, č. 17 (2007), s. 3065-3067 ISSN 0040-4039 R&D Projects: GA MŠk 1M0508 Grant - others:Descartes Prize(XE) HPAW-CT-2002-9001 Institutional research plan: CEZ:AV0Z40550506 Keywords : acyclic nucleoside phosphonates * thymidine phosphorylase * Suzuki coupling * pyrimidine Subject RIV: CC - Organic Chemistry Impact factor: 2.615, year: 2007

  7. 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.

  8. 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

  9. 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.

  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. 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.

  12. 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

  13. Preparation of crystalline starch nanoparticles using cold acid hydrolysis and ultrasonication.

    Science.gov (United States)

    Kim, Hee-Young; Park, Dong June; Kim, Jong-Yea; Lim, Seung-Taik

    2013-10-15

    Waxy maize starch in an aqueous sulfuric acid solution (3.16 M, 14.7% solids) was hydrolyzed for 2-6 days, either isothermally at 40 °C or 4 °C, or at cycled temperatures of 4 and 40 °C (1 day each). The starch hydrolyzates were recovered as precipitates after centrifuging the dispersion (10,000 rpm, 10 min). The yield of starch hydrolyzates depended on the hydrolysis temperature and time, which varied from 6.8% to 78%. The starch hydrolyzed at 40 °C or 4/40 °C exhibited increased crystallinity determined by X-ray diffraction analysis, but melted in broader temperature range (from 60 °C to 110 °C). However, the starch hydrolyzed at 4 °C displayed the crystallinity and melting endotherm similar to those of native starch. The starch hydrolyzates recovered by centrifugation were re-dispersed in water (15% solids), and the dispersion was treated by an ultrasonic treatment (60% amplitude, 3min). The ultrasonication effectively fragmented the starch hydrolyzates to nanoparticles. The hydrolyzates obtained after 6 days of hydrolysis were more resistant to the ultrasonication than those after 2 or 4 days, regardless of hydrolysis temperatures. The starch nanoparticles could be prepared with high yield (78%) and crystallinity by 4 °C hydrolysis for 6 days followed by ultrasonication. Scanning electron microscopy revealed that the starch nanoparticles had globular shapes with diameters ranging from 50 to 90 nm. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Some physicochemical and rheological properties of starch isolated from avocado seeds.

    Science.gov (United States)

    Chel-Guerrero, Luis; Barbosa-Martín, Enrique; Martínez-Antonio, Agustino; González-Mondragón, Edith; Betancur-Ancona, David

    2016-05-01

    Seeds from avocado (Persea americana Miller) fruit are a waste byproduct of fruit processing. Starch from avocado seed is a potential alternative starch source. Two different extraction solvents were used to isolate starch from avocado seeds, functional and rheological characteristics measured for these starches, and comparisons made to maize starch. Avocado seed powder was suspended in a solution containing 2 mM Tris, 7.5 mM NaCl and 80 mM NaHSO3 (solvent A) or sodium bisulphite solution (1500 ppm SO2, solvent B). Solvent type had no influence (p>0.05) on starch properties. Amylose content was 15-16%. Gelatinization temperature range was 56-74 °C, peak temperature was 65.7 °C, and transition enthalpy was 11.4-11.6J/g. At 90 °C, solubility was 19-20%, swelling power 28-30 g water/g starch, and water absorption capacity was 22-24 g water/g starch. Pasting properties were initial temperature 72 °C; maximum viscosity 380-390 BU; breakdown -2 BU; consistency 200 BU; and setback 198 BU. Avocado seed starch dispersions (5% w/v) were characterized as viscoelastic systems, with G'>G″. Avocado seed starch has potential applications as a thickening and gelling agent in food systems, as a vehicle in pharmaceutical systems and an ingredient in biodegradable polymers for food packaging. Copyright © 2016. Published by Elsevier B.V.

  15. 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)

  16. 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

  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. 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)

  19. 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 ...

  20. Assessment of Nutrient Contents of Modified Finger Millet (Eleusine coracana Starch

    Directory of Open Access Journals (Sweden)

    Tukura Bitrus Wokhe

    2017-02-01

    Full Text Available Modification processes can change the physicochemical and structural properties of native starch, thereby increasing its industrial applications. Finger millet starch (FMS was modified with casava starch (CS, guar gum (GG and xanthan gum (XG modifiers at the ratios of 95:5%, 90:10%, 80:20% and 75: 25%, for each of the modifier. The proximate and mineral compositions of the modified starch were determined using standard methods. Atomic absorption spectrometry method was used to quantify the mineral contents of the modified starch. Proximate contents of the modified FMS starch varied according to the type of the modifier and FMS/modifier ratios. Concentrations of carbohydrate in CS (66.97±0.03%, GG (64.42±0.05% and XG (64.64 ± 0.01% FMS modified starches were highest at 10%, 25% and 5% of the modifier contents repectively. The highest levels of fat in GG (8.91±0.02%, XG (7.89±0.01 and ash (3.55±0.02% in CS modified starches were recorded when the quantity of the modifiers were increased to 25%. Fatty acid levels in the modified starches varied in the order of XG (7.74±0.03% at 20% > GG (7.13±0.02% at 25% > CS (5.14±0.20% at 10%. At 25% modifier contents, levels of mineral element were highest in the modified CS and GG starches. Modifications decreased Mg, Mn, Fe, Zn, and Cu contents, while the concentrations Na, K, Ca and P increased. The modified starches can be used for production of some foods for specific health purposes.

  1. Chemical, morphological and functional properties of Brazilian jackfruit (Artocarpus heterophyllus L.) seeds starch.

    Science.gov (United States)

    Madruga, Marta Suely; de Albuquerque, Fabíola Samara Medeiros; Silva, Izis Rafaela Alves; do Amaral, Deborah Silva; Magnani, Marciane; Queiroga Neto, Vicente

    2014-01-15

    Starches used in food industry are extracted from roots, tubers and cereals. Seeds of jackfruit are abundant and contain high amounts of starch. They are discarded during the fruit processing or consumption and can be an alternative source of starch. The starch was extract from the jackfruit seeds and characterised to chemical, morphological and functional properties. Soft and hard jackfruit seeds showed starch content of 92.8% and 94.5%, respectively. Starch granules showed round and bell shape and some irregular cuts on their surface with type-A crystallinity pattern, similar to cereals starches. The swelling power and solubility of jackfruit starch increased with increasing temperature, showing opaque pastes. The soft seeds starch showed initial and final gelatinisation temperature of 36°C and 56°C, respectively; while hard seeds starch presented initial gelatinisation at 40°C and final at 61°C. These results suggest that the Brazilian jackfruit seeds starches could be used in food products. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Performance of high amylose starch-composited gelatin films influenced by gelatinization and concentration.

    Science.gov (United States)

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

    2017-01-01

    In order to study the impact of starch in film performance, high amylose corn starch was composited in gelatin films under different gelatinization conditions and, in high and low concentrations (10 and 50wt.%). It was found that hot water gelatinized starch (Gel-Shw) increased film mechanical strength and was dependent upon the starch concentration. The addition of an alkali component to the starch significantly enhanced the swelling of the starch granules and expedited the gelatinization process. Incorporation of starch, especially the alkalized starch (Sha), into the gelatin films decreased film solubility which improved its water resistance and water vapor permeability (WVP). Multiple techniques (DSC, TGA, FT-IR, and XRD) were used to characterize the process and results, including the crosslinking of the dissolved starch molecules and the particles formed from gelatinized starch during retrogradation process, which played an important role in improving the thermal stability of the composited gelatin films. Overall, the starch-gelatin composition provides a potential approach to improve gelatin film performance and benefit its applications in the food industry. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Effect of gamma-ray irradiation on starch in sweet popato roots

    International Nuclear Information System (INIS)

    Hayashi, T.; Todoroki, S.

    1994-01-01

    Starch contents, as well as the size and molecular weight, in sweet potato roots decreased during steerage at 30 degrees C after gamma-ray irradiation, accompanying the increase of sucrose content. No change in the starch and sucrose contents was observed in unirradiated specimens. By microscopy damaged starch granules were observed only in gamma-ray irradiated root. The results suggested that starch was converted into sucrose unirradiated sweet potato roots by the enzymes responsible for starch-sugar interconversion of which the activities were enhanced by gamma-ray irradiation

  4. Deficiency of maize starch-branching enzyme i results in altered starch fine structure, decreased digestibility and reduced coleoptile growth during germination

    Directory of Open Access Journals (Sweden)

    Yandeau-Nelson Marna

    2011-05-01

    Full Text Available Abstract Background Two distinct starch branching enzyme (SBE isoforms predate the divergence of monocots and dicots and have been conserved in plants since then. This strongly suggests that both SBEI and SBEII provide unique selective advantages to plants. However, no phenotype for the SBEI mutation, sbe1a, had been previously observed. To explore this incongruity the objective of the present work was to characterize functional and molecular phenotypes of both sbe1a and wild-type (Wt in the W64A maize inbred line. Results Endosperm starch granules from the sbe1a mutant were more resistant to digestion by pancreatic α-amylase, and the sbe1a mutant starch had an altered branching pattern for amylopectin and amylose. When kernels were germinated, the sbe1a mutant was associated with shorter coleoptile length and higher residual starch content, suggesting that less efficient starch utilization may have impaired growth during germination. Conclusions The present report documents for the first time a molecular phenotype due to the absence of SBEI, and suggests strongly that it is associated with altered physiological function of the starch in vivo. We believe that these results provide a plausible rationale for the conservation of SBEI in plants in both monocots and dicots, as greater seedling vigor would provide an important survival advantage when resources are limited.

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

    International Nuclear Information System (INIS)

    Nur Farhana Zainal Abiddin; Anida Yusoff; Noorlaila Ahmad

    2016-01-01

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

  6. 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.

  7. 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.

  8. 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.

  9. Preparation and properties of Starch-g-PLA/poly(vinyl alcohol) composite film.

    Science.gov (United States)

    Hu, Yingmo; Wang, Qingling; Tang, Mingru

    2013-07-25

    Starch/lactic acid graft copolymer (Starch-g-PLA) was prepared by the in situ copolymerization of starch grafted with lactic acid catalyzed with sodium hydroxide, and then mixed with poly(vinyl alcohol) (PVA) to get composite films. The structures of the graft copolymer and composite films were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The mechanical properties, water resistance, and thermal stability were also investigated. It was found that the compatibility of Starch-g-PLA and PVA was better than that of starch and PVA in the composite films. The tensile strength and elongation at break of the Starch-g-PLA/PVA composite film increased by 69.15% and 84.22%, respectively, while the water absorption decreased by 50.39%, which overcame the shortcomings of hydrophilicity and poor mechanical properties of Starch/PVA film. Thermogravimetric analysis (TGA) also showed that the thermal stability of Starch-g-PLA/PVA film was improved compared with Starch/PVA film. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. 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.

  11. 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 ...

  12. In vitro amylolysis of pulse and hylon VII starches explained in terms of their composition, morphology, granule architecture and interaction between hydrolysed starch chains.

    Science.gov (United States)

    Maaran, S; Hoover, R; Vamadevan, V; Waduge, R N; Liu, Q

    2016-02-01

    The objective of this study was to understand the factors underlying the susceptibility of pulse (lablab bean, navy bean, rice bean, tepary bean, velvet bean, and wrinkled pea) and hylon VII starches towards in vitro hydrolysis by the combined action of pancreatin and amyloglucosidase. The time taken to reach an equivalent level of hydrolysis (50%) varied significantly among the starches. Changes to molecular order, crystallinity, double helical content, radial orientation of starch chains (polarized light), enthalpy and apparent amylose content during the progress of hydrolysis showed that rate and extent of hydrolysis were influenced both by the structure of the native starches at different levels (molecular, mesoscopic, microscopic) of granule organization, and by the extent of retrogradation between hydrolysed starch chains. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. 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.

  14. 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.).

  15. 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...

  16. Production of small starch granules by expression of a tandem-repeat of a family 20 starch-binding domain (SBD3-SBD5) in an amylose-free potato genetic background

    NARCIS (Netherlands)

    Nazarian, F.; Trindade, L.M.; Visser, R.G.F.

    2012-01-01

    Starch exists typically as semicrystalline granules of varying size. Granule size plays an important role for many industrial starch applications. Microbial non-catalytic starch binding domains (SBD) exhibit an affinity for starch granules on their own. Three different constructs were introduced in

  17. Starch/fiber/poly(lactic acid) foam and compressed foam composites

    Science.gov (United States)

    Composites of starch, fiber, and poly(lactic acid) (PLA) were made using a foam substrate formed by dehydrating starch or starch/fiber gels. PLA was infiltrated into the dry foam to provide better moisture resistance. Foam composites were compressed into plastics using force ranging from 4-76MPa. Te...

  18. Comparison of Morphology and Physicochemical Properties of Starch Among 3 Arrowhead Varieties.

    Science.gov (United States)

    Li, Aimin; Zhang, Yunhong; Zhang, Yongji; Yu, Xurun; Xiong, Fei; Zhou, Rumei; Zhang, Yongtai

    2016-05-01

    Arrowhead (Sagittaria trifolia var. sinensis) is a source of starch worldwide, but arrowhead starch has been rarely studied. In this work, starch was separated from arrowhead corm. The morphology and physicochemical properties of starch were then investigated and compared among 3 different arrowhead varieties (Purple-corm, Hongta, and Japanese). Results showed that starches from the 3 varieties similarly featured an oval shape containing a visible polarization cross, a CA -type crystalline structure, and an ordered structure in the external granule region. However, starch content, granule size, crystal characteristics, and pasting properties differed among the 3 varieties. Japanese arrowhead exhibited the highest starch content and degree of ordered structure in the external granule region, as well as onset, peak, and final gelatinization temperature. Purple-corm arrowhead starch demonstrated the highest amylose content and relative degree of crystallinity, smallest granule size, and lowest swelling power and solubility. Purple-corm arrowhead starch also showed the highest gelatinization enthalpy, as well as peak, trough, final, and setback viscosities. This starch further presented the lowest breakdown viscosity and degree of hydrolysis by HCl and porcine pancreatic α-amylase. These findings can provide useful references for arrowhead variety selection in food and nonfood industries. © 2016 Institute of Food Technologists®

  19. Variability of electron spin resonance (ESR) signal of γ -irradiated starches

    International Nuclear Information System (INIS)

    Silva, Gilberto D.; Rodrigues Junior, Orlando; Mastro, Nelida L. del

    2017-01-01

    Food preservation is one of the practical applications of radiation processing of materials. Starch is an abundant and cheap nutritious biopolymer and also is the material for appropriate food systems and for technical industries. Starch granules are partially crystalline structures composed mainly of two types of starch: amylose, an essentially linear polymer, and amylopectin, with 3-44% of branch points. Electron spin resonance (ESR) spectroscopy is a very powerful and sensitive method for the characterization of the electronic structures of materials with unpaired electrons. The aim of the present work was to monitor the disappearance of the short life and long-life free radicals formed during γ-irradiation of 3 different starches. Corn, potato and fermented cassava starches were irradiated in a "6"0Co source Gammacell 220 with 20 kGy, dose rate around 1 kGy h"-"1. EPR spectra were obtained at room temperature using a Bruker EMX plus model, X band equipment. The main type of ESR signal from irradiated starch is a singlet with a g-value of about 2.0. The fading of ESR signals was followed for 350 hours, and presents differences among the different starch type reflecting differences in molecular arrangements of starch crystalline and amorphous fractions, although ESR spectra seemed to be common for all starches. (author)

  20. Variability of electron spin resonance (ESR) signal of γ -irradiated starches

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Gilberto D.; Rodrigues Junior, Orlando; Mastro, Nelida L. del, E-mail: nlmastro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-11-01

    Food preservation is one of the practical applications of radiation processing of materials. Starch is an abundant and cheap nutritious biopolymer and also is the material for appropriate food systems and for technical industries. Starch granules are partially crystalline structures composed mainly of two types of starch: amylose, an essentially linear polymer, and amylopectin, with 3-44% of branch points. Electron spin resonance (ESR) spectroscopy is a very powerful and sensitive method for the characterization of the electronic structures of materials with unpaired electrons. The aim of the present work was to monitor the disappearance of the short life and long-life free radicals formed during γ-irradiation of 3 different starches. Corn, potato and fermented cassava starches were irradiated in a {sup 60}Co source Gammacell 220 with 20 kGy, dose rate around 1 kGy h{sup -1}. EPR spectra were obtained at room temperature using a Bruker EMX plus model, X band equipment. The main type of ESR signal from irradiated starch is a singlet with a g-value of about 2.0. The fading of ESR signals was followed for 350 hours, and presents differences among the different starch type reflecting differences in molecular arrangements of starch crystalline and amorphous fractions, although ESR spectra seemed to be common for all starches. (author)

  1. Small-angle scattering studies show distinct conformations of calmodulin in its complexes with two peptides based on the regulatory domain of the catalytic subunit of phosphorylase kinase

    International Nuclear Information System (INIS)

    Trewhella, J.; Blumenthal, D.K.; Rokop, S.E.; Seeger, P.A.

    1990-01-01

    Small-angle X-ray and neutron scattering have been used to study the solution structures of calmodulin complexed with synthetic peptides corresponding to residues 342-366 and 301-326, designated PhK5 and PhK13, respectively, in the regulatory domain of the catalytic subunit of skeletal muscle phosphorylase kinase. The scattering data show that binding of PhK5 to calmodulin induces a dramatic contraction of calmodulin, similar to that previously observed when calmodulin is complexed with the calmodulin-binding domain peptide from rabbit skeletal muscle myosin light chain kinase. In contrast, calmodulin remains extended upon binding PhK13. In the presence of both peptides, calmodulin also remains extended. Apparently, the presence of PhK13 inhibits calmodulin from undergoing the PhK5-induced contraction. These data indicate that there is a fundamentally different type of calmodulin-target enzyme interaction in the case of the catalytic subunit of phosphorylase kinase compared with that for myosin light chain kinase

  2. 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...

  3. 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

  4. Effects of acid-hydrolysis and hydroxypropylation on functional properties of sago starch.

    Science.gov (United States)

    Fouladi, Elham; Mohammadi Nafchi, Abdorreza

    2014-07-01

    In this study, sago starch was hydrolyzed by 0.14M HCl for 6, 12, 18, and 24h, and then modified by propylene oxide at a concentration of 0-30% (v/w). The effects of hydrolysis and etherification on molecular weight distribution, physicochemical, rheological, and thermal properties of dually modified starch were estimated. Acid hydrolysis of starch decreased the molecular weight of starch especially amylopectin, but hydroxypropylation had no effect on the molecular weight distribution. The degree of Molar substitution (DS) of hydroxypropylated starch after acid hydrolysis ranged from 0.007 to 0.15. Dually modified starch with a DS higher than 0.1 was completely soluble in cold water at up to 25% concentration of the starch. This study shows that hydroxypropylation and hydrolysis have synergistic effects unlike individual modifications. Dually modified sago starch can be applied to dip-molding for food and pharmaceutical processing because of its high solubility and low tendency for retrogradation. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. 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 ...

  6. Food product models developed to evaluate starch as a food ingredient

    DEFF Research Database (Denmark)

    Wischmann, Bente; Bergsøe, Merete Norsker; Adler-Nissen, Jens

    2002-01-01

    Three highly reproducible food models have been developed to evaluate rheological and functional properties of starches. The food models are dutch vla, dressing, and white sauce, and they vary in pH, serving temperature, oil content, and content of other functional ingredients than starch (milk...... with starch concentration in dutch vla. In dressing and white sauce most of the rheological parameters depended on the starch concentration. In addition, it was found that results from the empirical rheological method (USDA consistometer) correlate well with fundamental rheological parameters. Syneresis...... was measured for a period of time up to 15 days. The degree of syneresis of dressing was highly dependent on starch concentration, while the syneresis of the white sauce was dependent on time but not on starch concentration. The dutch vla showed no syneresis at all....

  7. Structure and properties of pregelatinized cassava starch/kaolin composites

    International Nuclear Information System (INIS)

    Kaewtatip, Kaewta; Tanrattanakul, Varaporn

    2012-01-01

    Highlights: ► Pregelatinized starch/kaolin composites were prepared using compression molding. ► The tensile strengths of the composites were higher than for thermoplastic starch. ► Degradation temperatures of the composites were higher than for thermoplastic starch. ► The retrogradation behavior of the composites was hindered by kaolin. -- Abstract: Pregelatinized cassava starch/kaolin composites were prepared using compression molding. The morphology of the fractured surfaces, retrogradation behavior, thermal decomposition temperatures and mechanical properties of the composites were investigated using scanning election microscopy (SEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and tensile testing, respectively. The tensile strengths and thermal degradation temperatures of the composites were higher than for thermoplastic starch (TPS). The retrogradation behavior of the composites was hindered by kaolin. The water absorption was measured after aging for 12 and 45 days at a relative humidity (RH) of 15% and 55%. It indicated that all the composites displayed lower water absorption values than TPS.

  8. 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.

  9. 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.

  10. 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 ...

  11. 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.

  12. Thymine utilization in Escherichia coli K12. On the role of deoxyribose 1-phosphate and thymidine phosphorylase

    DEFF Research Database (Denmark)

    Jensen, Kaj Frank; Leer, Johan Christian; Nygaard, Per

    1973-01-01

    Exogenously supplied thymine is only poorly utilized by wild-type cells of Escherichia coli for the synthesis of their DNA. It appears that the lack of incorporation of exogenous thymine is due to a lack of endogenous deoxyribosyl groups, which are required for the synthesis of thymidine. Data...... to the external thymine concentration. The experiments in vivo led us to conclude that the incorporation of exogenous thymine occurs via thymidine, which is synthesized from thymine and deoxyribose 1-phosphate, catalyzed by thymidine phosphorylase. In accordance with this studies in vitro with purified thymidine...

  13. Cytological localization of adenosine kinase, nucleoside phosphorylase-1, and esterase-10 genes on mouse chromosome 14

    International Nuclear Information System (INIS)

    Samuelson, L.C.; Farber, R.A.

    1985-01-01

    The authors have determined the regional locations on mouse chromosome 14 of the genes for mouse adenosine kinase (ADK), nucleoside phosphorylase- 1 (NP-1), and esterase-10 (ES-10) by analysis of rearranged mouse chromosomes in gamma-irradiated Chinese hamster X mouse hybrid cell lines. Irradiated clones were screened for expression of the murine forms of these enzymes; segregant clones that expressed only one or two of the three markers were karyotyped. The patterns of enzyme expression in these segregants were correlated with the presence of rearranged chromosomes. The Adk gene was localized to bands A2 to B, Np-1 to bands B to C1, and Es-10 to bands D2 to E2

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

    Science.gov (United States)

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

    2006-12-27

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

  15. 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...

  16. 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.

  17. 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.

  18. 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

  19. Impact of Oxidative Stress on Ascorbate Biosynthesis in Chlamydomonas via Regulation of the VTC2 Gene Encoding a GDP-l-galactose Phosphorylase*

    Science.gov (United States)

    Urzica, Eugen I.; Adler, Lital N.; Page, M. Dudley; Linster, Carole L.; Arbing, Mark A.; Casero, David; Pellegrini, Matteo; Merchant, Sabeeha S.; Clarke, Steven G.

    2012-01-01

    The l-galactose (Smirnoff-Wheeler) pathway represents the major route to l-ascorbic acid (vitamin C) biosynthesis in higher plants. Arabidopsis thaliana VTC2 and its paralogue VTC5 function as GDP-l-galactose phosphorylases converting GDP-l-galactose to l-galactose-1-P, thus catalyzing the first committed step in the biosynthesis of l-ascorbate. Here we report that the l-galactose pathway of ascorbate biosynthesis described in higher plants is conserved in green algae. The Chlamydomonas reinhardtii genome encodes all the enzymes required for vitamin C biosynthesis via the l-galactose pathway. We have characterized recombinant C. reinhardtii VTC2 as an active GDP-l-galactose phosphorylase. C. reinhardtii cells exposed to oxidative stress show increased VTC2 mRNA and l-ascorbate levels. Genes encoding enzymatic components of the ascorbate-glutathione system (e.g. ascorbate peroxidase, manganese superoxide dismutase, and dehydroascorbate reductase) are also up-regulated in response to increased oxidative stress. These results indicate that C. reinhardtii VTC2, like its plant homologs, is a highly regulated enzyme in ascorbate biosynthesis in green algae and that, together with the ascorbate recycling system, the l-galactose pathway represents the major route for providing protective levels of ascorbate in oxidatively stressed algal cells. PMID:22393048

  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. Starch and oil in the donor cow diet and starch in substrate differently affect the in vitro ruminal biohydrogenation of linoleic and linolenic acids.

    Science.gov (United States)

    Zened, A; Troegeler-Meynadier, A; Nicot, M C; Combes, S; Cauquil, L; Farizon, Y; Enjalbert, F

    2011-11-01

    Trans isomers of fatty acids exhibit different health properties. Among them, trans-10,cis-12 conjugated linoleic acid has negative effects on milk fat production and can affect human health. A shift from the trans-11 to the trans-10 pathway of biohydrogenation (BH) can occur in the rumen of dairy cows receiving high-concentrate diets, especially when the diet is supplemented with highly unsaturated fat sources. The differences of BH patterns between linoleic acid (LeA) and linolenic acid (LnA) in such ruminal conditions remain unknown; thus, the aim of this work was to investigate in vitro the effects of starch and sunflower oil in the diet of the donor cows and starch level in the incubates on the BH patterns and efficiencies of LeA and LnA. The design was a 4 × 4 Latin square design with 4 cows, 4 periods, and 4 diets with combinations of 21 or 34% starch and 0 or 5% sunflower oil. The rumen content of each cow during each period was incubated with 4 substrates, combining 2 starch levels and either LeA or LnA addition. Capillary electrophoresis single-strand conformation polymorphism of incubates showed that dietary starch decreased the diversity of the bacterial community and the high-starch plus oil diet modified its structure. High-starch diets poorly affected isomerization and first reduction of LeA and LnA, but decreased the efficiencies of trans-11,cis-15-C18:2 and trans C18:1 reduction. Dietary sunflower oil increased the efficiency of LeA isomerization but decreased the efficiency of trans C18:1 reduction. An interaction between dietary starch and dietary oil resulted in the highest trans-10 isomers production in incubates when the donor cow received the high-starch plus oil diet. The partition between trans-10 and trans-11 isomers was also affected by an interaction between starch level and the fatty acid added to the incubates, showing that the trans-10 shift only occurred with LeA, whereas LnA was mainly hydrogenated via the more usual trans-11

  2. Modification of mechanical and thermal property of chitosan–starch blend films

    International Nuclear Information System (INIS)

    Tuhin, Mohammad O.; Rahman, Nazia; Haque, M.E.; Khan, Ruhul A.; Dafader, N.C.; Islam, Rafiqul; Nurnabi, Mohammad; Tonny, Wafa

    2012-01-01

    Chitosan–starch blend films (thickness 0.2 mm) of different composition were prepared by casting and their mechanical properties were studied. To improve the properties of chitosan–starch films, glycerol and mustard oil of different composition were used. Chitosan–starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. The modified films showed improvement in both tensile strength and elongation at break than the pure chitosan–starch films. Water uptake of the films reduced significantly than the pure chitosan–starch film. Thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) showed that the modified films experience less thermal degradation than the pure films. Scanning electron microscopy (SEM) and FTIR were used to investigate the morphology and molecular interaction of the blend film, respectively. - Highlights: ► Chitosan–starch blend films (thickness 0.2 mm) were prepared by casting. ► To improve the properties of chitosan–starch films, glycerol and mustard oil of different composition were used. ► Chitosan–starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. ► Properties of the modified films such as tensile strength, elongation at break, water uptake, TGA, DMA, SEM, FTIR were studied. ► Results indicate that modification of chitosan–starch film with mustard oil improved the properties of the blend films which could be further modified by HEMA using gamma radiation.

  3. 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.

  4. Sago Starch-Mixed Low-Density Polyethylene Biodegradable Polymer: Synthesis and Characterization

    Directory of Open Access Journals (Sweden)

    Md Enamul Hoque

    2013-01-01

    Full Text Available This research focuses on synthesis and characterization of sago starch-mixed LDPE biodegradable polymer. Firstly, the effect of variation of starch content on mechanical property (elongation at break and Young’s modulus and biodegradability of the polymer was studied. The LDPE was combined with 10%, 30%, 50%, and 70% of sago for this study. Then how the cross-linking with trimethylolpropane triacrylate (TMPTA and electron beam (EB irradiation influence the mechanical and thermal properties of the polymer was investigated. In the 2nd study, to avoid overwhelming of data LDPE polymer was incorporated with only 50% of starch. The starch content had direct influence on mechanical property and biodegradability of the polymer. The elongation at break decreased with increase of starch content, while Young’s modulus and mass loss (i.e., degradation were found to increase with increase of starch content. Increase of cross-linker (TMPTA and EB doses also resulted in increased Young’s modulus of the polymer. However, both cross-linking and EB irradiation processes rendered lowering of polymer’s melting temperature. In conclusion, starch content and modification processes play significant roles in controlling mechanical, thermal, and degradation properties of the starch-mixed LDPE synthetic polymer, thus providing the opportunity to modulate the polymer properties for tailored applications.

  5. 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)

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

    Science.gov (United States)

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

    2016-07-01

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

  7. Process development of starch hydrolysis using mixing characteristics of Taylor vortices.

    Science.gov (United States)

    Masuda, Hayato; Horie, Takafumi; Hubacz, Robert; Ohmura, Naoto; Shimoyamada, Makoto

    2017-04-01

    In food industries, enzymatic starch hydrolysis is an important process that consists of two steps: gelatinization and saccharification. One of the major difficulties in designing the starch hydrolysis process is the sharp change in its rheological properties. In this study, Taylor-Couette flow reactor was applied to continuous starch hydrolysis process. The concentration of reducing sugar produced via enzymatic hydrolysis was evaluated by varying operational variables: rotational speed of the inner cylinder, axial velocity (reaction time), amount of enzyme, and initial starch content in the slurry. When Taylor vortices were formed in the annular space, efficient hydrolysis occurred because Taylor vortices improved the mixing of gelatinized starch with enzyme. Furthermore, a modified inner cylinder was proposed, and its mixing performance was numerically investigated. The modified inner cylinder showed higher potential for enhanced mixing of gelatinized starch and the enzyme than the conventional cylinder.

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

    International Nuclear Information System (INIS)

    Suwanmala, Phiriyatorn; Hemvichian, Kasinee; Sonsuk, Manit

    2004-10-01

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

  9. Evaluation of tensile properties and water absortion of cassava starch film

    Science.gov (United States)

    Walster, R. Justin; Rozyanty, A. R.; Kahar, A. W. M.; Musa, L.; Shahnaz, S. B. S.

    2017-09-01

    Casava Starch film was prepared by casting method with different percentage of glycerol (0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5%) as plasticizer. The effect of glycerol content in starch film on mechanical and water absorption properties was studied. Results shows that the increase of glycerol content in cassava starch film had decrease the tensile strength, tensile modulus and increase the elongation of break properties. The result of water absorbency tended to increase for starch film with higher percentage of glycerol content. The incorporation of glycerol in cassava starch film had increase the water absorption ability due to increase of hydroxyl content contributed by glycerol.

  10. 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.

  11. 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.

  12. 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)

  13. Physicochemical and digestibility properties of double-modified banana ( Musa paradisiaca L.) starches.

    Science.gov (United States)

    Carlos-Amaya, Fandila; Osorio-Diaz, Perla; Agama-Acevedo, Edith; Yee-Madeira, Hernani; Bello-Pérez, Luis Arturo

    2011-02-23

    Banana starch was chemically modified using single (esterification or cross-linking) and dual modification (esterification-cross-linking and cross-linking-esterification), with the objective to increase the slowly digestible starch (SDS) and resistant starch (RS) concentrations. Physicochemical properties and in vitro digestibility were analyzed. The degree of substitution of the esterified samples ranged from 0.006 to 0.020. The X-ray diffraction pattern of the modified samples did not show change; however, an increase in crystallinity level was determined (from 23.79 to 32.76%). The ungelatinized samples had low rapidly digestible starch (RDS) (4.23-9.19%), whereas the modified starches showed an increase in SDS (from 10.79 to 16.79%) and had high RS content (74.07-85.07%). In the cooked samples, the esterified starch increased the SDS content (21.32%), followed by cross-linked starch (15.13%). Dual modified starch (cross-linked-esterified) had the lowest SDS content, but the highest RS amount. The esterified and cross-linked-esterified samples had higher peak viscosity than cross-linked and esterified-cross-linked. This characteristic is due to the fact that in dual modification, the groups introduced in the first modification are replaced by the functional group of the second modification. Temperature and enthalpy of gelatinization decreased in modified starches (from 75.37 to 74.02 °C and from 10.42 to 8.68 J/g, respectively), compared with their unmodified starch (76.15 °C and 11.05 J/g). Cross-linked-esterified starch showed the lowest enthalpy of gelatinization (8.68 J/g). Retrogradation temperature decreased in modified starches compared with unmodified (59.04-57.47 °C), but no significant differences were found among the modified samples.

  14. 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 ...

  15. In vitro Starch Hydrolysis Rate, Physico-chemical Properties and Sensory Evaluation of Butter Cake Prepared Using Resistant Starch Type III Substituted for Wheat Flour.

    Science.gov (United States)

    Pongjanta, J; Utaipattanaceep, A; Naivikul, O; Piyachomkwan, K

    2008-09-01

    Resistant starch type III (RS III) derived from enzymatically debranched high amylose rice starch was prepared and used to make butter cake at different levels (0, 5, 10, 15 and 20%) in place of wheat flour. Physico-chemical properties, sensory evaluation, and in vitro starch hydrolysis rate of the developed butter cake were investigated. This study showed that the content of resistant starch in butter cake increased significantly (Pcake with RS III replacement had a significantly lower in vitro starch hydrolysis rate compared to the control cake (0% RS III). The rates of starch hydrolysis from 0 to 180 min digestion time for 0, 5, 10 15, and 20% RS III in place of wheat flour in butter cakes were 3.70 to 67.65%, 2.97 to 64.86%, 2.86 to 59.99%, 2.79 to 55.96 and 2.78 to 53.04% respectively. The physico-chemical properties of 5 to 10% RS III substituted with wheat flour in the butter cake were not significantly different from the control cake and were moderately accepted by panellists in the sensory evaluation test.

  16. A Study of Moisture Sorption and Dielectric Processes of Starch and Sodium Starch Glycolate : Theme: Formulation and Manufacturing of Solid Dosage Forms Guest Editors: Tony Zhou and Tonglei Li.

    Science.gov (United States)

    Hiew, Tze Ning; Huang, Rongying; Popov, Ivan; Feldman, Yuri; Heng, Paul Wan Sia

    2017-12-01

    This study explored the potential of combining the use of moisture sorption isotherms and dielectric relaxation profiles of starch and sodium starch glycolate (SSG) to probe the location of moisture in dried and hydrated samples. Starch and SSG samples, dried and hydrated, were prepared. For hydrated samples, their moisture contents were determined. The samples were probed by dielectric spectroscopy using a frequency band of 0.1 Hz to 1 MHz to investigate their moisture-related relaxation profiles. The moisture sorption and desorption isotherms of starch and SSG were generated using a vapor sorption analyzer, and modeled using the Guggenheim-Anderson-de Boer equation. A clear high frequency relaxation process was detected in both dried and hydrated starches, while for dried starch, an additional slower low frequency process was also detected. The high frequency relaxation processes in hydrated and dried starches were assigned to the coupled starch-hydrated water relaxation. The low frequency relaxation in dried starch was attributed to the local chain motions of the starch backbone. No relaxation process associated with water was detected in both hydrated and dried SSG within the frequency and temperature range used in this study. The moisture sorption isotherms of SSG suggest the presence of high energy free water, which could have masked the relaxation process of the bound water during dielectric measurements. The combined study of moisture sorption isotherms and dielectric spectroscopy was shown to be beneficial and complementary in probing the effects of moisture on the relaxation processes of starch and SSG.

  17. Starch films from a novel (Pachyrhizus ahipa) and conventional sources: Development and characterization

    International Nuclear Information System (INIS)

    López, Olivia V.; García, María A.

    2012-01-01

    Biodegradable films from ahipa, cassava and corn native starches were developed by casting method and their physicochemical, mechanical and barrier properties were analyzed taking into account the different starch botanical sources. Filmogenic suspensions were prepared; their rheological behaviors were studied and all of them exhibited film-forming ability. However, mechanical assays demonstrated that unplasticized films were too rigid, limiting their technological applications. Thus, 1.5% w/w of glycerol as plasticizer was added to filmogenic suspensions and film flexibility and extensibility were improved, this effect was more significant for ahipa and cassava starch films. Furthermore, thickness, moisture content and water solubility of the developed films were increased when plasticizer was incorporated. Glycerol addition reduced film water vapor permeability and the lowest reduction corresponded to cassava starch films due to the high viscosity of its filmogenic suspensions. Plasticized starch films resulted to be UV radiation barriers; ahipa starch films had the lowest light absorption capacity and higher transparency than cassava and corn starch films. Dynamic-mechanical analysis indicated that plasticized films were partially miscible systems exhibiting two relaxations, one attributed to the starch-rich phase and the other to the glycerol-rich one. Likewise, it could be demonstrated that glycerol exerted a major plasticizing effect on ahipa starch matrixes. Highlights: ► Ahipa, cassava and corn starch films were developed by casting method. ► Glycerol effect on film mechanical behavior was major for tuberous starch films. ► Ahipa starch films resulted to be more transparent with lower UV absorption capacity. ► Plasticized films were partially miscible systems: with a glycerol-rich and a starch-rich phase. ► Glycerol exerted a major plasticizing effect on ahipa starch films.

  18. 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.

  19. Extrusion induced low-order starch matrices: Enzymic hydrolysis and structure.

    Science.gov (United States)

    Zhang, Bin; Dhital, Sushil; Flanagan, Bernadine M; Luckman, Paul; Halley, Peter J; Gidley, Michael J

    2015-12-10

    Waxy, normal and highwaymen maize starches were extruded with water as sole plasticizer to achieve low-order starch matrices. Of the three starches, we found that only high-amylose extrudate showed lower digestion rate/extent than starches cooked in excess water. The ordered structure of high-amylose starches in cooked and extruded forms was similar, as judged by NMR, XRD and DSC techniques, but enzyme resistance was much greater for extruded forms. Size exclusion chromatography suggested that longer chains were involved in enzyme resistance. We propose that the local molecular density of packing of amylose chains can control the digestion kinetics rather than just crystallinity, with the principle being that density sufficient to either prevent/limit binding and/or slow down catalysis can be achieved by dense amorphous packing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. EVALUATION OF MODIFIED RICE STARCH, A NEW EXCIPIENT FOR DIRECT COMPRESSION

    NARCIS (Netherlands)

    BOS, CE; BOLHUIS, GK; LERK, CF; DUINEVELD, CAA

    1992-01-01

    The compression characteristics of modified rice starch (Primotab(R)ET), a new excipient for the preparation of tablets by direct compression is evaluated. Modified rice starch is an agglomerated rice starch product. It has excellent flowing and disintegration properties. In contrast to other

  1. 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)

  2. Physicochemical and functional properties of gamma irradiated buckwheat and potato starch

    Science.gov (United States)

    Verma, Ruchi; Jan, Shumaila; Rani, Savita; Jan, Kulsum; Swer, Tanya L.; Prakash, Kumar S.; Dar, M. Z.; Bashir, Khalid

    2018-03-01

    Starches isolated from buckwheat and potato were subject to different doses of irradiation at 0, 5, 10, 15 and 20 kGy. Native and irradiated starch samples were evaluated for their physicochemical and functional properties to assess the effect of gamma irradiation. Apparent amylose content decreased significantly from 26.84% to 22.12% and 27.01 to 16.11% for buckwheat and potato starch respectively as the dose increased. A significant decrease was observed in pH, swelling power and syneresis as the dose increased for both buckwheat and potato starch. pH decreased from 5.20 to 3.81 and 5.81 to 3.95 for buckwheat and potato starch, respectively. Carboxyl content, freeze thaw stability, water and oil absorption capacity and transmittance showed increasing trend with increasing irradiation dose. Carboxyl content increased from 0% to 0.23% and 0-0.22% for buckwheat and potato starch, respectively.

  3. 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.

  4. Starch-assisted synthesis and optical properties of ZnS nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-15

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

  5. Starch-assisted synthesis and optical properties of ZnS nanoparticles

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  6. 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.

  7. Factors influencing gene silencing of granule-bound starch synthase in potato

    NARCIS (Netherlands)

    Heilersig, H.J.B.

    2005-01-01

    In the past, antisense RNA technology was used to modify the composition of potato tuber starch. Potato starch comprises amylose and amylopectin, polymers of glucose. Amylose production in potato is completely dependent on the presence of granule-bound starch synthase I (GBSSI). Inhibition of GBSSI

  8. 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...

  9. Essential work of fracture analysis for starch filled poly(propylene carbonate) composites

    International Nuclear Information System (INIS)

    Wang, X.L.; Li, R.K.Y.; Cao, Y.X.; Meng, Y.Z.

    2007-01-01

    Starch filled poly(propylene carbonate) composites are environmental friendly materials. In this study, the fracture toughness of composites under mode I loading was determined by the essential work of fracture concept. The specific essential fracture work of the poly(propylene carbonate)/starch composites decreases with increasing the starch content, while the non-essential work term, βw p increases with increasing the starch content. In addition, the morphologies, thermal properties, thermo-mechanical properties were studied by scanning electron microscope, thermogravimetric analysis, dynamic mechanical analysis, and differential scanning calorimetry, respectively. The thermal and thermo-mechanical measurements revealed that increasing starch content led to an increase in glass transition temperature and thermal stability. Morphology observation indicates that poly(propylene carbonate) and starch have weak interfacial adhesion

  10. The influence of starch oxidization and aluminate coupling agent on interfacial interaction, rheological behavior, mechanical and thermal properties of poly(propylene carbonate)/starch blends

    Science.gov (United States)

    Jiang, Guo; Zhang, Shui-Dong; Huang, Han-Xiong; The Key Laboratory of Polymer Processing Engineering of the Ministry of Education Team

    Poly(propylene carbonate) (PPC) is a kind of new biodegradable polymer that is synthesized by copolymerization of propylene oxide and carbon dioxide. In this work, PPC end-capped with maleic anhydride (PPCMA)/thermoplastic starch (TPS), PPCMA/thermoplastic oxidized starch (TPOS) and PPCMA/AL-TPOS (TPOS modified by aluminate coupling agent) blends were prepared by melt blending to improve its thermal and mechanical properties. FTIR results showed that there existed hydrogen-bonding interaction between PPCMA and starch. SEM observation revealed that the compatibility between PPCMA and TPOS was improved by the oxidation of starch. The enhanced interfacial interactions between PPCMA and TPOS led to a better performance of PPC blends such as storage modulus (G'), loss modulus (G''), complex viscosity (η*), tensile strength and thermal properties. Furthermore, the modification of TPOS by aluminate coupling agent (AL) facilitated the dispersion of oxidized starch in PPC matrix, and resulted in increasing the tensile strength and thermal stability. National Natural Science Foundation of China, National Science Fund of Guangdong Province.

  11. Quinoa starch granules as stabilizing particles for production of Pickering emulsions.

    Science.gov (United States)

    Rayner, Marilyn; Sjöö, Malin; Timgren, Anna; Dejmek, Petr

    2012-01-01

    Intact starch granules isolated from quinoa (Chenopodium quinoa Willd.) were used to stabilize emulsion drops in so-called Pickering emulsions. Miglyol 812 was used as dispersed phase and a phosphate buffer (pH7) with different salt (NaCl) concentrations was used as the continuous phase. The starch granules were hydrophobically modified to different degrees by octenyl succinic anhydride (OSA) or by dry heat treatment at 120 degrees C in order to study the effect on the resulting emulsion drop size. The degree of OSA-modification had a low to moderate impact on drop size. The highest level of modification (4.66%) showed the largest mean drop size, and lowest amount of free starch, which could be an effect of a higher degree of aggregation of the starch granules and, thereby, also the emulsion drops stabilized by them. The heat treated starch granules had a poor stabilizing ability and only the starch heated for the longest time (150 min at 120 degrees C) had a better emulsifying capacity than the un-modified native starch granules. The effect of salt concentration was rather limited. However, an increased concentration of salt slightly increased the mean drop size and the elastic modulus.

  12. Isolation and partial characterization of starch from banana cultivars grown in Colombia.

    Science.gov (United States)

    Chávez-Salazar, A; Bello-Pérez, L A; Agama-Acevedo, E; Castellanos-Galeano, F J; Álvarez-Barreto, C I; Pacheco-Vargas, G

    2017-05-01

    Banana starch is resistant to hydrolysis by digestive enzymes due to its structure and dietary fibre content. Starch was isolated from the following three cultivars of Colombian Musaceae: Gros Michel (dessert), Dominico Harton and FHIA 20 (cooking); also, the amylose and amylopectin contents, morphology of the granules, thermal properties, pasting, molecular characteristics and digestibility were determined. The total starch content, amylose content and digestibility (gelatinized starch) were higher in cooking varieties; the purity and gelatinization temperature were similar for the three varieties, but the enthalpy was higher in the dessert variety. The three varieties showed higher viscosities in the pasting profile compared to commercial maize starch in both acid and neutral conditions. Starch granules presented with heterogeneous sizes and shapes (elongated and ovals) that had birefringence. The Dominico Hartón variety showed the lowest rapidly digestible starch (RDS) value in the gelatinized sample that is in agreement with the greater proportion of long chains. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Kadouche, Derifa; Arias, Maria Cecilia

    2016-01-01

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

  14. 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)

  15. Mechanical and barrier properties of maize starch-gelatin composite films: effects of amylose content.

    Science.gov (United States)

    Wang, Kun; Wang, Wenhang; Ye, Ran; Xiao, Jingdong; Liu, Yaowei; Ding, Junsheng; Zhang, Shaojing; Liu, Anjun

    2017-08-01

    In order to obtain new reinforcing bio-fillers to improve the physicochemical properties of gelatin-based films, three types of maize starch, waxy maize starch (Ap), normal starch (Ns) and high-amylose starch (Al), were incorporated into gelatin film and the resulting film properties were investigated, focusing on the impact of amylose content. The thickness, opacity and roughness of gelatin film increased depending on the amylose content along with the starch concentration. The effects of the three starches on the mechanical properties of gelatin film were governed by amylose content, starch concentration as well as environmental relative humidity (RH). At 75% RH, the presence of Al and Ns in the gelatin matrix increased the film strength but decreased its elongation, while Ap exhibited an inverse effect. Starch addition decreased the oxygen permeability of the film, with the lowest value at 20% Al and Ns. All starches, notably at 30% content, led to a decrease in the water vapor permeability of the film at 90% RH, especially Ns starch. Furthermore, the starches improved the thermal stability of the film to some extent. Fourier transform infrared spectra indicated that some weak intermolecular interactions such as hydrogen bonding occurred between gelatin and starch. Moreover, a high degree of B-type crystallinity of starch was characterized in Gel-Al film by X-ray diffraction. Tailoring the properties of gelatin film by the incorporation of different types of maize starch provides the potential to extend its applications in edible food packaging. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  16. Amylolytic hydrolysis of native starch granules affected by granule surface area.

    Science.gov (United States)

    Kim, J C; Kong, B W; Kim, M J; Lee, S H

    2008-11-01

    Initial stage of hydrolysis of native starch granules with various amylolytic enzymes, alpha-amylase from Bacillus subtilis, glucoamylase I (GA-I) and II (GA-II) from Aspergillus niger, and beta-amylase from sweet potato showed that the reaction was apparently affected by a specific surface area of the starch granules. The ratios of the reciprocal of initial velocity of each amylolytic hydrolysis for native potato and maize starch to that for rice with the amylolytic enzymes were nearly equivalent to the ratio of surface area per mass of the 2 starch granules to that of rice, that is, 6.94 and 2.25, respectively. Thus, the reciprocal of initial velocity of each enzymatic hydrolysis as expressed in a Lineweaver-Burk plot was a linear function of the reciprocal of surface area for each starch granule. As a result, it is concluded that amylolytic hydrolysis of native starch granules is governed by the specific surface area, not by the mass concentration, of each granule.

  17. Swelling and tensile properties of starch glycerol system with various crosslinking agents

    Science.gov (United States)

    Mohamed, R.; Mohd, N.; Nurazzi, N.; Siti Aisyah, M. I.; Fauzi, F. Mohd

    2017-07-01

    Brittle properties of starch had been overcome by the modification process. In this work, sago starch is being modified with variable amount of plasticiser, namely glycerol at 20 and 40% and crosslinking agent had been added to the system. The film of the modification and characterizations of the starch glycerol system with various crosslinking systems were produced by casting method. The film properties of the starch glycerol system were then characterized by tensile strength (mechanical properties) and swelling (physical properties). The modification of the starch glycerol had improved that system by increasing the tensile strength, modulus however lowering its elongation. The increasing in percentage of the water absorption and also swelling are due to the intrinsic hydroxyl groups presence from the starch and glycerol itself that can attract more water to the system. Upon crosslinking, films casted with chemicals namely, glyoxal, malonic acid, borax, PEG were characterised. It was found that, all the film of sago starch crosslinked and undergoing easy film formation. From this modification, borax and malonic acid crosslinking agent had been determined as the best crosslinking agent to the starch glycerol system.

  18. 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.

  19. Process optimization for bioethanol production from cassava starch using novel eco-friendly enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Shanavas, S.; Padmaja, G.; Moorthy, S.N.; Sajeev, M.S.; Sheriff, J.T. [Division of Crop Utilization, Central Tuber Crops Research Institute, Thiruvananthapuram, 695 017 Kerala (India)

    2011-02-15

    Although cassava (Manihot esculenta Crantz) is a potential bioethanol crop, high operational costs resulted in a negative energy balance in the earlier processes. The present study aimed at optimizing the bioethanol production from cassava starch using new enzymes like Spezyme {sup registered} Xtra and Stargen trademark 001. The liquefying enzyme Spezyme was optimally active at 90 C and pH 5.5 on a 10% (w/v) starch slurry at levels of 20.0 mg (280 Amylase Activity Units) for 30 min. Stargen levels of 100 mg (45.6 Granular Starch Hydrolyzing Units) were sufficient to almost completely hydrolyze 10% (w/v) starch at room temperature (30 {+-} 1 C). Ethanol yield and fermentation efficiency were very high (533 g/kg and 94.0% respectively) in the Stargen + yeast process with 10% (w/v) starch for 48 h. Raising Spezyme and Stargen levels to 560 AAU and 91.2 GSHU respectively for a two step loading [initial 20% (w/v) followed by 20% starch after Spezyme thinning]/initial higher loading of starch (40% w/v) resulted in poor fermentation efficiency. Upscaling experiments using 1.0 kg starch showed that Stargen to starch ratio of 1:100 (w/w) could yield around 558 g ethanol/kg starch, with a high fermentation efficiency of 98.4%. The study showed that Spezyme level beyond 20.0 mg for a 10% (w/v) starch slurry was not critical for optimizing bioethanol yield from cassava starch, although an initial thinning of starch for 30 min by Spezyme facilitated rapid saccharification-fermentation by Stargen + yeast system. The specific advantage of the new process was that the reaction could be completed within 48.5 h at 30 {+-} 1 C. (author)

  20. 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) ...

  1. 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 ...

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. Physic-chemical Study of Starch Extracted from Irradiated Corn Flour

    International Nuclear Information System (INIS)

    Pozo Sanchez, R. del; Alvarez Gil, M.

    1986-01-01

    The effects of gamma irradiation on starch extracted from irradiated samples of corn flour were studied in the range 0,6 kGy-1,0 kGy. Amylographic properties, solubility and swelling powder of starch samples were determined immediately after irradiation and at 75 days storage at environment conditions (16 0 C-31 0 C, 55%-97% H.R.). Diffraction patterns of crystalline starch were also obtained by X-rays. Gelatinization temperature, swelling powder and diffraction patterns did not change upon irradiation, but a decrease in viscosity and an increase in starch solubility were observed within the dose-range and storage time studied. (author)

  7. 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.

  8. Effect of physico-chemical starch properties on bread quality and ageing (model study)

    International Nuclear Information System (INIS)

    Gambus, H.

    1997-01-01

    Wheat, rye and triticale starches, both native and those subjected to: segregation according to small granules (type B) and the large ones (type A), defatting with n-propanol and NaOH solution and irradiation by gamma rays at doses 3 and 5 kGy, as well as oat starch were analysed to determine their basic physico-chemical properties. Then all these starches were used in test with baking model pup loaves (40 g) from artificially composed flour, according to starch-gluten system based on recipe (for 4 pup loaves): 80 g starch d.m., 20 g dry vital gluten d.m., 8 g sugar, 3 g salt, 1 g yeast and 70 cm 3 water at 30 o C. Starch was the only alternative component in baking recipes. Additionally, wheat breads of 250 g were baked, in which part of flour was replaced by wheat and triticale starch fraction of large granules, irradiated rye and wheat starches, as well as by oat starch. Pup loaves and 250 g-loaves were evaluated on the day baking and during 3-day storage. Following parameters were determined: volume, penetration and crumb moisture and content of dry matter in crust. Also, sensory scores were performed. In addition, every day water extract from the pup loaves crumbs was prepared and in it dry matter and blue value as an indicator of soluble amylose were determined as well as carbohydrate substances were identified according to molecular mass using gel chromatography. Based on the results obtained negative effects of small starch granules and of a supplement of oat starch on bread quality were found, in spite of a beneficial effect of fatty substances contained in it, on retardation of the crumb hardening process. Also, a positive share of starch phospholipids was ascertained, not only in the retardation of amylose retrogradation but also in stabilization of crumb pores. It was observed that intensity of amylose retrogradation in crumb is determined by both the content of fatty substances in starch granules and the ratio of bound water by starch and protein

  9. 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...

  10. 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.

  11. Rheological, pasting, thermal and retrogradation properties of octenyl succinic anhydride modified potato starch

    Directory of Open Access Journals (Sweden)

    Chuin WON

    Full Text Available Abstract The objective of the present study was to investigate the rheological, pasting, and thermal properties of octenyl succinic anhydrate (OSA-modified potato starch. Potato starch was modified using different concentrations of OSA (0, 1, 3, and 5%, v/v. The degree of substitution (DS for the OSA-modified starch ranged from 0.0012 to 0.0055. The amylose leaching values of native and OSA-modified potato starch with different DS levels were in the range of 47.09-87.32%. The gel strength values of the OSA-modified starch were lower than those of native potato starch. Rapid Visco Analyzer data showed that peak, hot pasting, final and setback viscosities of the native starch decreased after OSA modification. Dynamic shear rheological tests, conducted at 4 °C, indicated that OSA-modified potato starch had weak gel-like behavior with the storage moduli (G' higher than the loss moduli (G” over most of the frequency ranges (0.63-63.8 rad·s-1.

  12. Preparation and Characterization of Starch Nanoparticles for Controlled Release of Curcumin

    Directory of Open Access Journals (Sweden)

    Suk Fun Chin

    2014-01-01

    Full Text Available Curcumin was loaded onto starch nanoparticles by using in situ nanoprecipitation method and water-in-oil microemulsion system. Curcumin loaded starch nanoparticles exhibited enhanced solubility in aqueous solution as compared to free curcumin. Effects of formulation parameters such as types of reaction medium, types of surfactant, surfactant concentrations, oil/ethanol ratios, loading time, and initial curcumin concentration were found to affect the particle size and loading efficiency (LF of the curcumin loaded starch nanoparticles. Under optimum conditions, curcumin loaded starch nanoparticles with mean particles size of 87 nm and maximum loading efficiency of 78% were achieved. Curcumin was observed to release out from starch nanoparticles in a sustained way under physiological pH over a period of 10 days.

  13. 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...

  14. 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...

  15. Rape embryogenesis. IV. Appearance and disappearance of starch during embryo development

    Directory of Open Access Journals (Sweden)

    Teresa Tykarska

    2014-01-01

    Full Text Available Starch appears first in the suspensor of the proembryo with two-cell apical part. It is observed in the embryo proper from the octant stage. At first it is visible in all the embryo cells in the form of minute transient grains which disappear during cell divisions. But the columella mother cells and their derivatives have persistent large grains. When the embryo turns green in the heart stage a gradual accumulation of storage starch begins and lasts to the end of embryogenesis. Storage starch grains appear first in the auter cortex layers of the hypocotyl where the largest grains are to be found later, and afterwards in all the other tissues. Starch is usually absent in the frequently dividing cells, but even there it appears in the form of minute grains after the end of cell divisions. Disappearance of starch starts when the intensive green colour of the seed coat begins to fade. The first to disappear are the smallest granules in the regions where they were noted latest. In the embryo axis the starch grains remain deposited longest in dermatogen and cortex cells in the lower hypocotyl part. They are visible there, still when the seed turns brown. In black seeds starch may be only found in the columella the cells of which throughout embryogenesis contain amyloplasts filled with starch. These grains disappear completely at the time when the seeds become dry.

  16. 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...

  17. Organic acid profile of commercial sour cassava starch

    Directory of Open Access Journals (Sweden)

    DEMIATE I.M.

    1999-01-01

    Full Text Available Organic acids are present in sour cassava starch ("polvilho azedo" and contribute with organoleptic and physical characteristics like aroma, flavor and the exclusive baking property, that differentiate this product from the native cassava starch. Samples of commercial sour cassava starch collected in South and Southeast Brazil were prepared for high performance liquid chromatography (HPLC analysis. The HPLC equipment had a Biorad Aminex HPX-87H column for organic acid analysis and a refractometric detector. Analysis was carried out with 0.005M sulfuric acid as mobile phase, 0.6ml/min flow rate and column temperature of 60° C. The acids quantified were lactic (0.036 to 0.813 g/100g, acetic (0 to 0.068 g/100g, propionic (0 to 0.013 g/100g and butyric (0 to 0.057 g/100g, that are produced during the natural fermentation of cassava starch. Results showed large variation among samples, even within the same region. Some samples exhibited high acid levels, mainly lactic acid, but in these neither propionic nor butyric acids were detected. Absence of butyric acid was not expected because this is an important component of the sour cassava starch aroma, and the lack of this acid may suggest that such samples were produced without the natural fermentation step.

  18. All-natural bio-plastics using starch-betaglucan composites.

    Science.gov (United States)

    Sagnelli, Domenico; Kirkensgaard, Jacob J K; Giosafatto, Concetta Valeria L; Ogrodowicz, Natalia; Kruczała, Krzysztof; Mikkelsen, Mette S; Maigret, Jean-Eudes; Lourdin, Denis; Mortensen, Kell; Blennow, Andreas

    2017-09-15

    Grain polysaccharides represent potential valuable raw materials for next-generation advanced and environmentally friendly plastics. Thermoplastic starch (TPS) is processed using conventional plastic technology, such as casting, extrusion, and molding. However, to adapt the starch to specific functionalities chemical modifications or blending with synthetic polymers, such as polycaprolactone are required (e.g. Mater-Bi). As an alternative, all-natural and compostable bio-plastics can be produced by blending starch with other polysaccharides. In this study, we used a maize starch (ST) and an oat β-glucan (BG) composite system to produce bio-plastic prototype films. To optimize performing conditions, we investigated the full range of ST:BG ratios for the casting (100:0, 75:25, 50:50, 25:75 and 0:100 BG). The plasticizer used was glycerol. Electron Paramagnetic Resonance (EPR), using TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) as a spin probe, showed that the composite films with high BG content had a flexible chemical environment. They showed decreased brittleness and improved cohesiveness with high stress and strain values at the break. Wide-angle X-ray diffraction displayed a decrease in crystallinity at high BG content. Our data show that the blending of starch with other natural polysaccharides is a noteworthy path to improve the functionality of all-natural polysaccharide bio-plastics systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. 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.

  20. Combined effects of added beta glucan and black tea in breads on starch functionality.

    Science.gov (United States)

    Jalil, Abbe Maleyki M; Edwards, Christine A; Combet, Emilie; Ibrahim, Muhammad; Garcia, Ada L

    2015-03-01

    Bread and tea are usually consumed separately, but there may be different food-matrix interactions and changes in starch characteristics when they are combined in bread. This study developed breads (white bread, WF; black tea, BT; beta glucan, βG; beta glucan plus black tea, βGBT) and determined their starch functionalities. Breads were developed using a standard baking recipe and determined their starch characteristics. There was no significant difference in starch hydrolysis between BT and WF but βGBT reduced early (10 min) starch hydrolysis compared with βG. The starch granules in βG and βGBT were elliptical and closely packed together. These results suggest that the addition of beta glucan and black tea to bread preserved the elliptical starch granules and lowered short-term starch hydrolysis.

  1. 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

  2. Encapsulation and delivery of food ingredients using starch based systems.

    Science.gov (United States)

    Zhu, Fan

    2017-08-15

    Functional ingredients can be encapsulated by various wall materials for controlled release in food and digestion systems. Starch, as one of the most abundant natural carbohydrate polymers, is non-allergenic, GRAS, and cheap. There has been increasing interest of using starch in native and modified forms to encapsulate food ingredients such as flavours, lipids, polyphenols, carotenoids, vitamins, enzymes, and probiotics. Starches from various botanical sources in granular or amorphous forms are modified by chemical, physical, and/or enzymatic means to obtain the desired properties for targeted encapsulation. Other wall materials are also employed in combination with starch to facilitate some types of encapsulation. Various methods of crafting the starch-based encapsulation such as electrospinning, spray drying, antisolvent, amylose inclusion complexation, and nano-emulsification are introduced in this mini-review. The physicochemical and structural properties of the particles are described. The encapsulation systems can positively influence the controlled release of food ingredients in food and nutritional applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. 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.

  4. X-ray diffraction pattern and relative crystallinity of irradiated arrowroot starch

    Energy Technology Data Exchange (ETDEWEB)

    Barroso, Aline G.; Garcia, Rafael H.L.; Del Mastro, Nelida L., E-mail: nlmastro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-11-01

    After cereals, tubers and roots are the major source of starch for food and industrial uses. Arrowroot refers to any plant of the genus Marantha, but the term is most commonly used to describe the easily digested starch obtained from the rhizomes of Marantha arundinacae. The rhizomes of this herbaceous plant contain about 20% of starch. As few studies exist on arrowroot starch, the objective of this preliminary work was to study the X-ray diffraction patterns (XRD) patterns of arrowroot starch when treated by γ-radiation with doses up to 15 kGy in a {sup 60}Co source. The XRD patterns of the arrowroot starch exhibited A-type crystalline arrangements with strong peaks at approximately 15º, 17º, 18º and 23º (2θ). A slight increase of diffractogram peaks intensity was noticed after the irradiation process. The crystallinity index was calculated using Bruker DIFFRAC.EVA version 4.2 software. Relative crystallinity seems to increase with radiation doses, and this effect is more noticeable at low doses. That can be attributed to different radiation sensitivity among the amorphous and crystalline regions of the arrowroot starch molecule. Present results will contribute to elucidate the behavior under radiation treatment of this starchy component increasingly employed by the food industry. (author)

  5. Raw starch digestion by. alpha. -amylase and glucoamylase from Chalara paradoxa

    Energy Technology Data Exchange (ETDEWEB)

    Monma, Mitsura; Yamamoto, Yoshihiro; Kagei, Norio; Kainuma, Keiji

    1989-10-01

    Glucoamylase and {alpha}-amylase of Chalara paradoxa were separated by hydrophobic column chromatography using butyl-Toyopearl 650M. The {alpha}-amylase showed the highest activity at pH 5.5 and 45{sup 0}C, and was stable in the pH range of 5.5-6.5 and at temperatures lower than 40{sup 0}C. The glucoamylase showed the highest activity at pH 5.0 and 45{sup 0}C, and was stable in the pH range of 4.0-7.5 and at temperatures lower than 45{sup 0}C. The molecular mass of the {alpha}-amylase and glucoamylase estimated by SDS polyacrylamide gel electrophoresis was 80,000 and 68,000, respectively. Both glucoamylase and {alpha}-amylase could digest more effectively raw rice starch and raw corn starch than raw sago starch and raw potato starch. 2% raw rice starch in 10 ml solution was digested by more than 90% by 100 units of each amylase. When these amylases were used combined, raw corn starch was more effectively digested than they were used singly. This cooperative action in raw corn starch digestion was also observed when C. paradoxa {alpha}-amylase and R. niveus glucoamylase were combined. (orig.).

  6. X-ray diffraction pattern and relative crystallinity of irradiated arrowroot starch

    International Nuclear Information System (INIS)

    Barroso, Aline G.; Garcia, Rafael H.L.; Del Mastro, Nelida L.

    2017-01-01

    After cereals, tubers and roots are the major source of starch for food and industrial uses. Arrowroot refers to any plant of the genus Marantha, but the term is most commonly used to describe the easily digested starch obtained from the rhizomes of Marantha arundinacae. The rhizomes of this herbaceous plant contain about 20% of starch. As few studies exist on arrowroot starch, the objective of this preliminary work was to study the X-ray diffraction patterns (XRD) patterns of arrowroot starch when treated by γ-radiation with doses up to 15 kGy in a "6"0Co source. The XRD patterns of the arrowroot starch exhibited A-type crystalline arrangements with strong peaks at approximately 15º, 17º, 18º and 23º (2θ). A slight increase of diffractogram peaks intensity was noticed after the irradiation process. The crystallinity index was calculated using Bruker DIFFRAC.EVA version 4.2 software. Relative crystallinity seems to increase with radiation doses, and this effect is more noticeable at low doses. That can be attributed to different radiation sensitivity among the amorphous and crystalline regions of the arrowroot starch molecule. Present results will contribute to elucidate the behavior under radiation treatment of this starchy component increasingly employed by the food industry. (author)

  7. 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.

  8. 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)

  9. 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.

  10. 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....

  11. 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.

  12. Effect of heat moisture treatment (HMT) on product quality of sorghum starch

    Science.gov (United States)

    Haryani, Kristinah; Hadiyanto, Handayani, Noera; Nugraheni, Dwi; Suryanto

    2015-12-01

    Sorghum is a cereal plant that rich of nutrition contents. The high content of carbohydrate in sorghum make this plant can be processed into one of the processed food i.e vermicelli. To give better quality, it is necessary to use flour substitution from sorghum starch. The aim of this study was to evaluate the treatment of natural sorghum starch substitution, the addition of CMC, and a comparison of the natural starch with starch sorghum forage sorghum against solid losses value, rehydration weight and texture profiles. The variable used in this study: amount of natural sorghum starch subtituion (10%, 20%, 30%, 40%, 50%), the addition of CMC (0.1%; 0.2%; 0.3%; 0.4%; 0.5%) and substituting sorghum starch Natural: HMT sorghum starch (1: 1; 1: 2; 1: 3; 1: 4; 1: 5) and the quality parameters were evaluated. The result indicated that to substitute sorghum starch naturally at a rate of 50% had the best results with a value of solid losses 5.1% (white sorghum) 5.83% (red sorghum) and weighing rehydration 301.82% (white sorghums) 293.16% (red sorghum), the addition of CMC with 0.5% concentration of 3.96% solid losses value (red sorghum) 4:21% (white sorghums) and weight rehydration 252.71% (white sorghums) 244.45% (red sorghums).

  13. Effect of starch type on the physico-chemical properties of edible films.

    Science.gov (United States)

    Basiak, Ewelina; Lenart, Andrzej; Debeaufort, Frédéric

    2017-05-01

    Food preservation is mostly related to packaging in oil-based plastics, inducing environmental problems, but this drawback could be limited by using edible/biodegradable films and coatings. Physical and chemical properties were assessed and reflect the role of the starch type (wheat, corn or potato) and thus that of the amylose/amylopectin ratio, which influences thickness, colour, moisture, wettability, thermal, surface and mechanical properties. Higher amylose content in films induces higher moisture sensitivity, and thus affects the mechanical and barrier properties. Films made from potato starch constitute a greater barrier for oxygen and water vapour though they have weaker mechanical properties than wheat and corn starch films. Starch species with higher amylose content have lower wettability properties, and better mechanical resistance, which strongly depends on the water content due to the hydrophilic nature of starch films, so they could be used for products with higher water activity, such as cheese, fruits and vegetables. It especially concerns wheat starch systems, and the contact angle indicates less hydrophilic surfaces (above 90°) than those of corn and potato starch films (below 90°). The starch origin influences optical properties and thickness: with more amylose, films are opalescent and thicker; with less, they are transparent and thinner. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. 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.

  15. Effects of amino acids on the physiochemical properties of potato starch.

    Science.gov (United States)

    Cui, Min; Fang, Ling; Zhou, Hongxian; Yang, Hong

    2014-05-15

    The objective of this study was to evaluate effects of different amino acid additives (phenylalanine (Phe), methionine (Met), lysine (Lys), arginine (Arg), aspartic acid (Asp) and glutamic acid (Glu)) on the physicochemical properties of potato starch gels. Charge-carrying amino acids (Lys, Arg, Asp and Glu) significantly decreased the swelling power, solubility, light transmittance, L(∗) value and gel strength of potato starch, but increased syneresis during freeze-thaw treatment, while neutral amino acids (Phe and Met) did not cause modifications in starch gels. During heating, potato starch with fortified charge-carrying amino acids showed a lower peak G' (storage modulus), when compared with Phe and Met. Results showed that charge-carrying amino acids could modify physicochemical properties and improve the nutritional values of starch-based products. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Modification of mechanical and thermal property of chitosan-starch blend films

    Science.gov (United States)

    Tuhin, Mohammad O.; Rahman, Nazia; Haque, M. E.; Khan, Ruhul A.; Dafader, N. C.; Islam, Rafiqul; Nurnabi, Mohammad; Tonny, Wafa

    2012-10-01

    Chitosan-starch blend films (thickness 0.2 mm) of different composition were prepared by casting and their mechanical properties were studied. To improve the properties of chitosan-starch films, glycerol and mustard oil of different composition were used. Chitosan-starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. The modified films showed improvement in both tensile strength and elongation at break than the pure chitosan-starch films. Water uptake of the films reduced significantly than the pure chitosan-starch film. Thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) showed that the modified films experience less thermal degradation than the pure films. Scanning electron microscopy (SEM) and FTIR were used to investigate the morphology and molecular interaction of the blend film, respectively.

  17. Ultra-small and anionic starch nanospheres: formation and vitro thrombolytic behavior study.

    Science.gov (United States)

    Huang, Yinjuan; Ding, Shenglong; Liu, Mingzhu; Gao, Chunmei; Yang, Jinlong; Zhang, Xinjie; Ding, Bin

    2013-07-25

    This paper is considered as the first report on the investigation of nattokinase (NK) release from anionic starch nanospheres. The ultra-small and anionic starch nanospheres were prepared by the method of reverse micro-emulsion crosslinking in this work. Starch nanospheres were characterized through Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). Effects of preparation conditions on particle size were studied. The cytotoxicity, biodegradable and vitro thrombolytic behaviors of nattokinase (NK) loaded anionic starch nanospheres were also studied. The results showed that the anionic starch nanospheres are non-toxic, biocompatible and biodegradable. Moreover, the anionic starch nanospheres can protect NK from fast biodegradation hence prolongs the circulation in vivo and can reduce the risk of acute hemorrhage complication by decreasing the thrombolysis rate. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Rheological and gelation properties of rice starch modified with 4-alpha-glucanotransferase.

    Science.gov (United States)

    Lee, Kwang Yeon; Kim, Yong-Ro; Park, Kwan Hwa; Lee, Hyeon Gyu

    2008-04-01

    Rheological measurements were performed to characterize rice starch modified with 4-alpha-glucanotransferase (4alphaGTase) isolated from Thermus scotoductus, in terms of effects of the enzyme and starch concentration on flow behavior, gel strength, and melting and gelling kinetics of the modified rice starch. Consistency index decreased and flow behavior index increased with the level of enzyme treatment, and at high level of enzyme treatment, it demonstrated Bingham plastic behavior. As the level of enzyme decreased and the starch concentration increased, gelation time decreased and the final gel strength increased significantly. Regardless of treatment variables, all the modified starch gels melted at similar temperature.

  19. Engineering the chloroplast targeted malarial vaccine antigens in Chlamydomonas starch granules.

    Directory of Open Access Journals (Sweden)

    David Dauvillée

    2010-12-01

    Full Text Available Malaria, an Anopheles-borne parasitic disease, remains a major global health problem causing illness and death that disproportionately affects developing countries. Despite the incidence of malaria, which remains one of the most severe infections of human populations, there is no licensed vaccine against this life-threatening disease. In this context, we decided to explore the expression of Plasmodium vaccine antigens fused to the granule bound starch synthase (GBSS, the major protein associated to the starch matrix in all starch-accumulating plants and algae such as Chlamydomonas reinhardtii.We describe the development of genetically engineered starch granules containing plasmodial vaccine candidate antigens produced in the unicellular green algae Chlamydomonas reinhardtii. We show that the C-terminal domains of proteins from the rodent Plasmodium species, Plasmodium berghei Apical Major Antigen AMA1, or Major Surface Protein MSP1 fused to the algal granule bound starch synthase (GBSS are efficiently expressed and bound to the polysaccharide matrix. Mice were either immunized intraperitoneally with the engineered starch particles and Freund adjuvant, or fed with the engineered particles co-delivered with the mucosal adjuvant, and challenged intraperitoneally with a lethal inoculum of P. Berghei. Both experimental strategies led to a significantly reduced parasitemia with an extension of life span including complete cure for intraperitoneal delivery as assessed by negative blood thin smears. In the case of the starch bound P. falciparum GBSS-MSP1 fusion protein, the immune sera or purified immunoglobulin G of mice immunized with the corresponding starch strongly inhibited in vitro the intra-erythrocytic asexual development of the most human deadly plasmodial species.This novel system paves the way for the production of clinically relevant plasmodial antigens as algal starch-based particles designated herein as amylosomes, demonstrating that

  20. Engineering the chloroplast targeted malarial vaccine antigens in Chlamydomonas starch granules.

    Science.gov (United States)

    Dauvillée, David; Delhaye, Stéphane; Gruyer, Sébastien; Slomianny, Christian; Moretz, Samuel E; d'Hulst, Christophe; Long, Carole A; Ball, Steven G; Tomavo, Stanislas

    2010-12-15

    Malaria, an Anopheles-borne parasitic disease, remains a major global health problem causing illness and death that disproportionately affects developing countries. Despite the incidence of malaria, which remains one of the most severe infections of human populations, there is no licensed vaccine against this life-threatening disease. In this context, we decided to explore the expression of Plasmodium vaccine antigens fused to the granule bound starch synthase (GBSS), the major protein associated to the starch matrix in all starch-accumulating plants and algae such as Chlamydomonas reinhardtii. We describe the development of genetically engineered starch granules containing plasmodial vaccine candidate antigens produced in the unicellular green algae Chlamydomonas reinhardtii. We show that the C-terminal domains of proteins from the rodent Plasmodium species, Plasmodium berghei Apical Major Antigen AMA1, or Major Surface Protein MSP1 fused to the algal granule bound starch synthase (GBSS) are efficiently expressed and bound to the polysaccharide matrix. Mice were either immunized intraperitoneally with the engineered starch particles and Freund adjuvant, or fed with the engineered particles co-delivered with the mucosal adjuvant, and challenged intraperitoneally with a lethal inoculum of P. Berghei. Both experimental strategies led to a significantly reduced parasitemia with an extension of life span including complete cure for intraperitoneal delivery as assessed by negative blood thin smears. In the case of the starch bound P. falciparum GBSS-MSP1 fusion protein, the immune sera or purified immunoglobulin G of mice immunized with the corresponding starch strongly inhibited in vitro the intra-erythrocytic asexual development of the most human deadly plasmodial species. This novel system paves the way for the production of clinically relevant plasmodial antigens as algal starch-based particles designated herein as amylosomes, demonstrating that efficient production

  1. 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.

  2. Structural changes of starch during baking and staling of rye bread.

    Science.gov (United States)

    Mihhalevski, Anna; Heinmaa, Ivo; Traksmaa, Rainer; Pehk, Tõnis; Mere, Arvo; Paalme, Toomas

    2012-08-29

    Rye sourdough breads go stale more slowly than wheat breads. To understand the peculiarities of bread staling, rye sourdough bread, wheat bread, and a number of starches were studied using wide-angle X-ray diffraction, nuclear magnetic resonance ((13)C CP MAS NMR, (1)H NMR, (31)P NMR), polarized light microscopy, rheological methods, microcalorimetry, and measurement of water activity. The degree of crystallinity of starch in breads decreased with hydration and baking to 3% and increased during 11 days of storage to 21% in rye sourdough bread and to 26% in wheat bread. (13)C NMR spectra show that the chemical structures of rye and wheat amylopectin and amylose contents are very similar; differences were found in the starch phospholipid fraction characterized by (31)P NMR. The (13)C CP MAS NMR spectra demonstrate that starch in rye sourdough breads crystallize in different forms than in wheat bread. It is proposed that different proportions of water incorporation into the crystalline structure of starch during staling and changes in starch fine structure cause the different rates of staling of rye and wheat bread.

  3. 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; ...

  4. Molecular characterization and in vitro digestibility of normal maize starch hydrolyzed by maltotriohydrolase.

    Science.gov (United States)

    Wu, Chunsen; Zhou, Xing; Wei, Benxi; Li, Hongyan; Tian, Yaoqi; Ali, Barkat; Xu, Xueming; Jin, Zhengyu

    2015-03-01

    Normal maize starch was hydrolyzed by the glucan 1,4-alpha-maltotriohydrolase (AMTS), and the changes in molecular characteristics and digestibility of starch were evaluated. Upon hydrolysis, maltotriose purity could be modified via controlled AMTS action. The transglycosylation of AMTS possibly happened during the extensive hydrolysis of starch. No single linear association between the z-average radius of gyration (Rz), conformation exponent (ν), apparent molecular density (ρ) and weight average molar mass (Mw) of the starch molecules could be established in the entire process of AMTS hydrolysis. Under mild hydrolysis (≤240 min), Rz and ρ displayed linear relationships with Mw. However, transitions of ν, Rz and ρ appeared after extensive hydrolysis (>240 min), due to the increase in the amount of short chains [degree of polymerization (DP)≤5]. The spherical starch molecule tends toward less compact and a structure between sphere and random coil after extensive hydrolysis. And the increase in the amount of DP≤12 chains and reduction of molecular dimension after AMTS hydrolysis restrict the digestibility of starch. The results of this study suggest that normal maize starch can be modulated by AMTS to produce the desired maltotriose syrup, starch molecular characteristics, and starch digestibility. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Enzymic hydrolysis of starch in continuous alcoholic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Yarovenko, V.L.; Pykhova, S.V.; Ustinnikov, B.A.; Lazareva, A.N.; Makeev, D.M.

    1965-01-01

    Fermentations were conducted on a plant scale, using starch of various origins, e.g., potatoes, wheat, and other cereals, and as enzyme source a number of strains of Aspergillus oryzae, A. awamori, A. usamii, A. niger, A. batatae, and Bacillus mesentericus. The starches were broken down to a molecular weight between 900 and 1600; time requirements differed from those commonly known. Comparison of these enzymic actions to that of standard malt discloses that in breaking down a potato starch from a molecular weight of 268,000 to one of 1353 to 1556, the malt and A. Oryzae require 1 hour, whereas A. awamori and B. mesentericus require 18, and a different strain of A. awamori requires 24 hours.

  6. Processing surface sizing starch using oxidation, enzymatic hydrolysis and ultrasonic treatment methods--Preparation and application.

    Science.gov (United States)

    Brenner, Tobias; Kiessler, Birgit; Radosta, Sylvia; Arndt, Tiemo

    2016-03-15

    The surface application of starch is a well-established method for increasing paper strength. In surface sizing, a solution of degraded starch is applied to the paper. Two procedures have proved valuable for starch degradation in the paper mill: enzymatic and thermo-oxidative degradation. The objective of this study was to determine achievable efficiencies of cavitation in preparing degraded starch for surface application on paper. It was found that ultrasonic-assisted starch degradation can provide a starch solution that is suitable for surface sizing. The molecular composition of starch solutions prepared by ultrasonic treatment differed from that of starch solutions degraded by enzymes or by thermo-oxidation. Compared to commercial degradation processes, this resulted in intensified film formation and in greater penetration during surface sizing and ultimately in a higher starch content of the paper. Paper sized with ultrasonically treated starch solutions show the same strength properties compared to commercially sized paper. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. A Forgotten Application of the Starch Test: C[subscript 4] Photosynthesis

    Science.gov (United States)

    Harley, Suzanne M.

    2013-01-01

    In many labs on photosynthesis, the presence of starch in leaves is used as an indirect indicator of photosynthetic activity. Students do starch tests on leaves from plants that have been kept under a variety of conditions in order to check parameters for photosynthesis. The starch test can also be used to enable students to discover differences…

  8. A Comparative Study of the Syneresis of Yam Starches and other ...

    African Journals Online (AJOL)

    The syneresis of starch gels from 19 yam cultivars (belonging to 4 Dioscorea species and complex of species) and 5 modified starches were studied during refrigeration (4°C) and freezing (-20°C). Syneresis of starch gels evolved on refrigeration at the onset from zero and remained constant between 20% to 60% after 8 ...

  9. Biodegradable foam trays obtained from mixtures of non-irradiated and irradiated cassava starches

    International Nuclear Information System (INIS)

    Brant, A.J.C.; Naime, N.; Lugao, A.B.; Ponce, P.

    2015-01-01

    Biodegradable polymers, such as starch, cellulose, PHB, PLA, and derivatives thereof, are being studied to produce innovative packaging in the most diverse shapes (films, bags, trays, bottles, etc.) to attend this current market trend. The aim of this work was to produce foam trays from cassava starch for food packaging by extrusion-thermopressing process. Their formulations were based on non-irradiated and γ-irradiated starches at diverse radiation absorbed doses (kGy) in order to evaluate the influence of the irradiated starches on the physical properties of the trays. Water absorption results showed an irregular increase with the increase of the absorbed dose: 26.32% and 39.84% for the trays based on starch 0 kGy and 1:1 (w/w) mixture of starches 0 kGy and 100.0 kGy, respectively. Other physicochemical properties were evaluated from the starches utilized and the trays obtained. (author)

  10. Biodegradable foam trays obtained from mixtures of non-irradiated and irradiated cassava starches

    Energy Technology Data Exchange (ETDEWEB)

    Brant, A.J.C.; Naime, N.; Lugao, A.B.; Ponce, P., E-mail: thonybrant@gmail.com, E-mail: patiponce@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Biodegradable polymers, such as starch, cellulose, PHB, PLA, and derivatives thereof, are being studied to produce innovative packaging in the most diverse shapes (films, bags, trays, bottles, etc.) to attend this current market trend. The aim of this work was to produce foam trays from cassava starch for food packaging by extrusion-thermopressing process. Their formulations were based on non-irradiated and γ-irradiated starches at diverse radiation absorbed doses (kGy) in order to evaluate the influence of the irradiated starches on the physical properties of the trays. Water absorption results showed an irregular increase with the increase of the absorbed dose: 26.32% and 39.84% for the trays based on starch 0 kGy and 1:1 (w/w) mixture of starches 0 kGy and 100.0 kGy, respectively. Other physicochemical properties were evaluated from the starches utilized and the trays obtained. (author)

  11. 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 ...

  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. 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

  14. Effect of addition of different hydrocolloids on pasting, thermal, and rheological properties of cassava starch

    Directory of Open Access Journals (Sweden)

    Tatiana Dias Leite

    2012-09-01

    Full Text Available Starches and gums are hydrocolloids frequently used in food systems to provide proper texture, moisture, and water mobility. Starch-gum interaction in food systems can change the starch granule swelling and its gelatinization and rheological properties. In this study, the effect of the addition of xanthan gum (XG, sodium carboxymethyl cellulose (SCMC, and carrageenan (CAR at the concentrations of the 0.15, 0.25, 0.35 and 0.45% (w/v on the pasting, thermal, and rheological properties of cassava starch was studied. The swelling power (SP and the scanning electron microscopy (SEM of the starch gels were also evaluated. The results obtained showed that xanthan gum (XG had a strong interaction with the cassava starch penetrating between starch granules causing increase in pasting viscosities, SP, storage and loss (G', and G", respectively modulus and reduction in the setback of the starch; sodium carboxymethyl cellulose (SCMC greatly increased the pasting viscosities, the SP, and the storage and loss (G', and G", respectively modulus of the starch-mixtures, mainly due to its greater capacity to hold water and not due to the interaction with cassava starch. Carrageenan (CAR did not change any of the starch properties since there was no interaction between this gum and cassava starch at the concentrations used.

  15. 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...

  16. The effect of Gamma-irradiation on the functional properties of starch

    International Nuclear Information System (INIS)

    BenBettaieb, Nasreddine

    2008-01-01

    Irradiation is one of the effective methods able to change starch structure and its functional properties. In this research the effect of gamma-irradiation (3, 5, 10, 20 and 50kGy) on the rheological, structural, thermal and morphological properties of corn starch was studied. Viscoamylograph test showed that the maximal consistency of the starch paste and its corresponding temperature decrease with increasing irradiation dose. Textural analysis of paste starch using strain-relaxation test showed the dominance of behaviour elastic after irradiation. Discriminant function analysis (DFA) revealed a good discrimination of the irradiation doses among rheological parameters in the strain-relaxation test. FTIR spectra showed that the irradiated starch displayed a significant decrease in the intensity of the O.H stretch (3000.3600 cm 1 ), C.H stretch (2800.3000 cm 1 ), bending mode of water (1600.1800 cm 1 ) and bending mode of glycosidic linkage (900-950 cm-1). The X-ray diffraction spectra show that did not any modification in the sharp and intensity of peaks after irradiation dose. Differential scanning calorimetry (DSC) of corn starch showed decreases in onset (To), final (Tf) and peak (Tp) gelatinisation temperature with increasing irradiation dose. icrophotographs of polarized light microscopy (LPM) showed that up to 50 kGy irradiation did not present any visible physical effect on the corn starch granule. (Author)

  17. Starch digestion in the small intestine of broiler chickens differs among feedstuffs

    NARCIS (Netherlands)

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

    2001-01-01

    Dietary starch is the major energy source for broiler chickens, and knowledge about its digestive behavior can be important. In a digestibility trial with 720 broiler chickens, site, rate and extent of starch digestion were measured for 12 feedstuffs. Starch digestion was determined using the

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

    Directory of Open Access Journals (Sweden)

    H.L. Abd El-Mohdy

    2016-11-01

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

  19. Preparation and properties of thermoplastic poly(caprolactone) composites containing high amount of esterified starch without plasticizer.

    Science.gov (United States)

    Sun, Yujie; Hu, Qiongen; Qian, Jiangtao; Li, Ting; Ma, Piming; Shi, Dongjian; Dong, Weifu; Chen, Mingqing

    2016-03-30

    Based on stearyl chloride and native starch, esterified starch were prepared and the chemical structure was characterized by (1)H NMR and FTIR. It was found that stearyl chloride was an efficient agent to fabricate esterified starch with high degree of substitution (DS). During the melt blending of esterified starch (80 wt%) and poly(caprolactone) (PCL, 20 wt%), it was shown the torque of PCL/esterified starch was much lower than that of PCL/native starch without any plasticizer, and further decreased with increasing DS. Compared with PCL/native starch, the tensile properties of PCL/esterified starch composites were significantly enhanced. The tensile strength and elongation at break were increased from 2.7 MPa to 56% for PCL/native starch composites to 9.1 MPa and 626% for PCL/esterified starch ones with DS of 1.50, respectively. SEM observation revealed the esterified starch particles in matrix became smaller and more uniform. In addition, the water resistance and hydrophobic character of PCL/esterified starch composites were improved. PCL composites containing 80 wt% esterified starch with favorable mechanical properties would have great potential applications in broad areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. A new generation of starch products as excipient in pharmaceutical tablets .1. Preparation and binding properties of high surface area potato starch products

    NARCIS (Netherlands)

    Wierik, GHPT; ArendsScholte, AW; Eissens, AC; Lerk, CF

    1996-01-01

    A new pharmaceutical excipient with a high binding capacity was prepared from potato starch by enzymatic degradation, followed by suitable dehydration of the precipitated and filtered retrograded starch to produce high specific surface area products. Thermal dehydration methods like drying at room