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...

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...

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...

Action of amylolytic and pullulytic enzymes from various anaerobic thermophiles on linear and branched glucose polymers

Energy Technology Data Exchange (ETDEWEB)

Koch, R [Goettingen Univ. (Germany, F.R.). Inst. fuer Mikrobiologie; Antranikian, G [Technische Univ. Hamburg-Harburg, Hamburg (Germany, F.R.). Arbeitsbereich Biotechnologie 1

1990-10-01

A detailed study has been conducted on the action of starch hydrolyzing enzymes from thermophilic anaerobic bacteria belonging to the genera Clostridium, Thermoanaerobacter and Thermobacteroides. The appearance of multiple bands on polyacrylamide gels with amylolytic as well as pullulytic activities was shown to be a general feature of bacteria investigated. Analysis of the hydrolysis products of each protein band clearly demonstrated the capability of these organisms to hydrolyze {alpha}-1,4-glycosidic bonds in linear oligosaccharides and {alpha}-1,6-glycosidic linkages in pullulan. Furthermore, the enzyme system of thermophilic bacteria investigated was also capable of attacking in the {alpha}-1,6-linkages in branched oligosaccharides. Due to the action of these thermoactive enzymes with multiple specificity an almost complete hydrolysis of raw starch and maltodextrin could be achieved under the same conditions and in one step. (orig.).

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.

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

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...

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

Design starch: stochastic modeling of starch granule biogenesis.

Science.gov (United States)

Raguin, Adélaïde; Ebenhöh, Oliver

2017-08-15

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

Design starch: stochastic modeling of starch granule biogenesis

Science.gov (United States)

Ebenhöh, Oliver

2017-01-01

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

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.

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.

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.

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...

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.

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.

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....

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.

Enzyme-modified starch as an oil delivery system for bake-only chicken nuggets.

Science.gov (United States)

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

2014-05-01

This study investigated the effects of enzyme modification on starch as an effective oil delivery system for bake-only chicken nuggets. Various native starches were hydrolyzed by amyloglucosidase to a hydrolysis degree of 20% to 25% and plated with 50% (w/w, starch dry basis) with canola oil to create a starch-oil matrix. This matrix was then blended into a dry ingredient blend for batter and breader components. Nuggets were prepared by coated with predust, hydrated batter, and breader, and the coated nuggets were steam-baked until fully cooked and then frozen until texture and sensory analyses. The enzyme-modified starches showed a significant decrease in pasting viscosities for all starch types. For textural properties of nuggets, no clear relationship was found between peak force and starch source or amylose content. Sensory attributes related to fried foods (for example, crispness and mouth-coating) did not significantly differ between bake-only nuggets formulated using the enzyme-modified starches and the partially fried and baked ones. The present findings suggest that enzyme-modified starches can deliver sufficient quantity of oil to create sensory attributes similar to those of partially fried chicken nuggets. Further study is needed to optimize the coating formulation of bake-only chicken nugget to become close to the fried one in sensory aspects. The food industry has become increasingly focused on healthier items. Frying imparts several critical and desirable product functionalities, such as developing texture and color, and providing mouth-feel and flavor. The food industry has yet to duplicate all of the unique characteristics of fried chicken nuggets with a baking process. This study investigated the application of enzyme-modified starch as an oil delivery system in bake-only chicken nugget formulation in attempts to provide characteristics of fried items. This information is useful to improve the nutritional value of fried food by eliminating the

Replacement of traditional seawater-soluble pigments by starch and hydrolytic enzymes in polishing antifouling coatings

DEFF Research Database (Denmark)

Olsen, Søren Martin; Pedersen, L. T.; Dam-Johansen, Kim

2010-01-01

The use of starch and hydrolytic enzymes as replacement for traditional polishing pigments (e.g., Cu2O and ZnO) in antifouling coatings has been investigated. The enzymes facilitate a slow conversion of water-insoluble starch into water-soluble glucose, and dissolution of glucose causes the devel......The use of starch and hydrolytic enzymes as replacement for traditional polishing pigments (e.g., Cu2O and ZnO) in antifouling coatings has been investigated. The enzymes facilitate a slow conversion of water-insoluble starch into water-soluble glucose, and dissolution of glucose causes...... the development of a leached (porous) layer in the wetted, outermost part of the coating. Subsequent water-binder interaction at the pore walls gives rise to polishing, in a manner similar to that of conventional antifouling coatings. Different starch types have been evaluated and classified as potential coating...

Structural and Digestion Properties of Soluble-, Slowly Digestible and Resistant Maltodextrin from Cassava Starch by Enzymatic Modification

DEFF Research Database (Denmark)

Sorndech, Waraporn

The combination of branching enzyme (BE) and amylomaltase (AM) were selected to modify cassava starch. AM were used to elongate the glucan chains in order to enhance BE activity to create branching linkages. Cassava starch were gelatinized and incubated with BE or AMBE or BEAMBE or simultaneous...... AM and BE. The molecular analysis of the products including amylopectin chain length distribution, content of α-1,6 glucosidic linkages, absolute molecular weight distribution and digestibility were examined. Only BE catalysis showed 7.8% of branching linkages. The sequential AMBE-treated starch...... showed 9.9%-10.0% branching linkages, while the sequential BEAMBE-treated starch gained 10.9%-13.1% of branching linkages. Moreover, the sequential AMBE and BEAMBE-treated starch retarded the digestion rate of α-amylase and glucoamylase. Overall, sequential BEAMBE catalysis resulted in more...

Hydration properties and phosphorous speciation in native, gelatinized and enzymatically modified potato starch analyzed by solid-state MAS NMR

DEFF Research Database (Denmark)

Larsen, Flemming H.; Kasprzak, Miroslaw Marek; Lærke, Helle Nygaard

2013-01-01

Hydration of granular, gelatinized and molecularly modified states of potato starch in terms of molecular mobility were analyzed by 13C and 31P solid-state MAS NMR. Gelatinization (GEL) tremendously reduced the immobile fraction compared to native (NA) starch granules. This effect was enhanced...... by enzyme-assisted catalytic branching with branching enzyme (BE) or combined BE and β-amylase (BB) catalyzed exo-hydrolysis. Carbons of the glycosidic α-1,6 linkages required high hydration rates before adopting uniform chemical shifts indicating solid-state disorder and poor water accessibility...... regions was only observed in NA starch. Moreover phosphorous was observed in a minor pH-insensitive form and as major phosphate in hydrated GEL and BE starches....

Effect of enzyme treatment on pea starch physicomechanical properties of biofilms

OpenAIRE

A. Sh. Zakirova; T. N. Manahova; A. V. Kanarskiy; Z. A. Kanarskaya

2013-01-01

The regularities of change in physical and mechanical properties of biofilms based on pea starch treated with pullulanase enzyme preparation were obtained. The possibility of formation of linear pea starch amylopectin polymers, which contribute to improvement of the mechanical and rheological properties of biofilms was identified.

An Extracellular Cell-Attached Pullulanase Confers Branched α-Glucan Utilization in Human Gut Lactobacillus acidophilus.

Science.gov (United States)

Møller, Marie S; Goh, Yong Jun; Rasmussen, Kasper Bøwig; Cypryk, Wojciech; Celebioglu, Hasan Ufuk; Klaenhammer, Todd R; Svensson, Birte; Abou Hachem, Maher

2017-06-15

Of the few predicted extracellular glycan-active enzymes, glycoside hydrolase family 13 subfamily 14 (GH13_14) pullulanases are the most common in human gut lactobacilli. These enzymes share a unique modular organization, not observed in other bacteria, featuring a catalytic module, two starch binding modules, a domain of unknown function, and a C-terminal surface layer association protein (SLAP) domain. Here, we explore the specificity of a representative of this group of pullulanases, Lactobacillus acidophilus Pul13_14 ( La Pul13_14), and its role in branched α-glucan metabolism in the well-characterized Lactobacillus acidophilus NCFM, which is widely used as a probiotic. Growth experiments with L. acidophilus NCFM on starch-derived branched substrates revealed a preference for α-glucans with short branches of about two to three glucosyl moieties over amylopectin with longer branches. Cell-attached debranching activity was measurable in the presence of α-glucans but was repressed by glucose. The debranching activity is conferred exclusively by La Pul13_14 and is abolished in a mutant strain lacking a functional La Pul13_14 gene. Hydrolysis kinetics of recombinant La Pul13_14 confirmed the preference for short-branched α-glucan oligomers consistent with the growth data. Curiously, this enzyme displayed the highest catalytic efficiency and the lowest K m reported for a pullulanase. Inhibition kinetics revealed mixed inhibition by β-cyclodextrin, suggesting the presence of additional glucan binding sites besides the active site of the enzyme, which may contribute to the unprecedented substrate affinity. The enzyme also displays high thermostability and higher activity in the acidic pH range, reflecting adaptation to the physiologically challenging conditions in the human gut. IMPORTANCE Starch is one of the most abundant glycans in the human diet. Branched α-1,6-glucans in dietary starch and glycogen are nondegradable by human enzymes and constitute a

Effect of enzyme treatment on pea starch physicomechanical properties of biofilms

Directory of Open Access Journals (Sweden)

A. Sh. Zakirova

2013-01-01

Full Text Available The regularities of change in physical and mechanical properties of biofilms based on pea starch treated with pullulanase enzyme preparation were obtained. The possibility of formation of linear pea starch amylopectin polymers, which contribute to improvement of the mechanical and rheological properties of biofilms was identified.

Statistically designed optimisation of enzyme catalysed starch removal from potato pulp

DEFF Research Database (Denmark)

Thomassen, Lise Vestergaard; Meyer, Anne S.

2010-01-01

to obtain dietary fibers is usually accomplished via a three step, sequential enzymatic treatment procedure using a heat stable alpha-amylase, protease, and amyloglucosidase. Statistically designed experiments were performed to investigate the influence of enzyme dose, amount of dry matter, incubation time...... and temperature on the amount of starch released from the potato pulp. The data demonstrated that all the starch could be released from potato pulp in one step when 8% (w/w) dry potato pulp was treated with 0.2% (v/w) (enzyme/substrate (E/S)) of a thermostable Bacillus licheniformis alpha-amylase (Termamyl(R) SC...

Production of native-starch-degrading enzymes by a Bacillus firmus/lentus strain

NARCIS (Netherlands)

Wijbenga, Dirk-Jan; Beldman, Gerrit; Veen, Anko; Binnema, Doede

1991-01-01

A bacterium belonging to the Bacillus firmus/lentus-complex and capable of growth on native potato starch was isolated from sludge of a pilot plant unit for potato-starch production. Utilization of a crude enzyme preparation obtained from the culture fluid after growth of the microorganism on native

Improved production of an enzyme that hydrolyses raw yam starch by Penicillium sp. S-22 using fed-batch fermentation.

Science.gov (United States)

Sun, Hai-Yan; Ge, Xiang-Yang; Zhang, Wei-Guo

2006-11-01

A newly isolated strain, Penicillium sp. S-22, was used to produce an enzyme that hydrolyses raw yam starch [raw yam starch digesting enzyme (RYSDE)]. The enzyme activity and overall enzyme productivity were respectively 16 U/ml and 0.19 U/ml h in the batch culture. The enzyme activity increased to 85 U/ml by feeding of partially hydrolyzed raw yam starch. When a mixture containing partially hydrolyzed raw yam starch and peptone was fed by a pH-stat strategy, the enzyme activity reached 366 U/ml, 23-fold of that obtained in the batch culture, and the overall productivity reached 3.4 U/ml h, which was 18-fold of that in the batch culture.

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)

Recycle bioreactor for bioethanol production from wheat starch. 1. Cold enzyme hydrolysis

Energy Technology Data Exchange (ETDEWEB)

Lang, X.; Hill, G.A.; MacDonald, D.G. [Department of Chemical Engineering, Saskatchewan (Canada)

2001-06-01

A 5 L membrane bioreactor system has been designed and operated at low temperature to hydrolyze starch granules directly to sugars using barley {alpha}-amylase. The system includes a temperature and pH controlled, well-mixed bioreactor; microfilters to separate and recycle granules; and ultrafilters to separate and recycle enzyme molecules. Operation in batch mode demonstrated similar kinetics and low productivity observed earlier in shake flasks, whereas continuous flow operation was not successful due to enzyme inhibition and degradation. Sequential batch mode operation, involving filtration after each batch hydrolysis, produced optimum productivity measured at 0.16 grams of starch granules hydrolyzed per gram of enzyme per hour for more than 100 hours of operation. (author)

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

Science.gov (United States)

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

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...

Inhibition of raw starch digestion by one glucoamylase preparation from black Aspergillus at high enzyme concentration

Energy Technology Data Exchange (ETDEWEB)

Saka, B C; Veda, S

1981-09-01

Raw starch digestion by glucoamylase I (Ab. G-I) preparation from black Aspergillus was inhibited significantly at relatively high concentration of the enzyme. The properties of this enzyme were studied together with those of another glucoamylase I (Nor. G-I), also from black Aspergillus. The two glucoamylases do not differ so much in their physico-chemical properties such as molecular weight, pH and thermal stability, pH and temperature optimum, substrate specificity, debranching activity, isoelectric point etc. The adsorption rate of both enzymes on raw starch increased by the increase of enzyme concentration. The raw starch digestion rate by adsorbed Ab. G-I, however, was decreased with the increase of concentration of enzyme whereas the same was increased in case of Nor. G-I. The inhibitory effect was weaker at 60 deg. Celcius or above. (Refs. 11).

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

Science.gov (United States)

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

2014-10-01

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

A gene encoding starch branching enzyme I (SBEI) in apple (Malusxdomestica, Rosaceae) and its phylogenetic relationship to Sbe genes from other angiosperms.

Science.gov (United States)

Han, Yuepeng; Gasic, Ksenija; Sun, Fengjie; Xu, Mingliang; Korban, Schuyler S

2007-06-01

An apple starch-branching enzyme SbeI gene (GenBank Accession No. DQ115404) has been isolated, cloned, and sequenced. The SbeI is a single copy gene in the apple genome, consisting of 14 exons and 13 introns, and covering 6075bp. As detected by RT-PCR, the apple SbeI is expressed at very low levels during early stages of fruit development; while, the highest levels of mRNA transcripts are observed at approximately 44 days post-pollination. Besides fruits, the apple SbeI is also expressed in buds and flowers, and very weakly in leaves. The genomic structure of SbeI in apple is strikingly similar to those reported so far in grasses (Poaceae), with exons 4 through 13 being of identical lengths in both apple and grasses. Moreover, structure similarities in exon lengths have also been detected in SbeII genes of both grasses and eudicots. These findings prompted the investigation of the evolutionary process of the Sbe gene family in angiosperms. A total of 26 Sbe sequences, representing an array of monocots and eudicots, are investigated in this study. Phylogenetic analysis has suggested that Sbe genes have duplicated into SbeI and SbeII prior to the divergence of moncots from eudicots. The SbeII gene is further duplicated into SbeIIa and SbeIIb prior to the radiation of grasses; however, it is not yet clear whether this duplication event has occurred before or after the radiation of the eudicots.

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

Science.gov (United States)

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

2015-02-01

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

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

Enzyme-resistant dextrins from potato starch for potential application in the beverage industry.

Science.gov (United States)

Jochym, Kamila Kapusniak; Nebesny, Ewa

2017-09-15

The objective of this study was to produce soluble enzyme-resistant dextrins by microwave heating of potato starch acidified with small amounts of hydrochloric and citric acids and to characterize their properties. Twenty five samples were initially made and their solubility was determined. Three samples with the highest water solubility were selected for physico-chemical (dextrose equivalent, molecular weight distribution, pasting characteristics, retrogradation tendency), total dietary fiber (TDF) analysis, and stability tests. TDF content averaged 25%. Enzyme-resistant dextrins practically did not paste, even at 20% samples concentration, and were characterized by low retrogradation tendency. The stability of the samples, expressed as a percentage increase of initial and final reducing sugar content, at low pH and during heating at low pH averaged 10% and 15% of the initial value, respectively. The results indicate that microwave heating could be an effective and efficient method of producing highly-soluble, low-viscous, and enzyme-resistant potato starch dextrins. Copyright © 2017 Elsevier Ltd. All rights reserved.

Expression and characterization of thermostable glycogen branching enzyme from Geobacillus mahadia Geo-05

Directory of Open Access Journals (Sweden)

Nur Syazwani Mohtar

2016-12-01

Full Text Available The glycogen branching enzyme (EC 2.4.1.18, which catalyses the formation of α-1,6-glycosidic branch points in glycogen structure, is often used to enhance the nutritional value and quality of food and beverages. In order to be applicable in industries, enzymes that are stable and active at high temperature are much desired. Using genome mining, the nucleotide sequence of the branching enzyme gene (glgB was extracted from the Geobacillus mahadia Geo-05 genome sequence provided by the Malaysia Genome Institute. The size of the gene is 2013 bp, and the theoretical molecular weight of the protein is 78.43 kDa. The gene sequence was then used to predict the thermostability, function and the three dimensional structure of the enzyme. The gene was cloned and overexpressed in E. coli to verify the predicted result experimentally. The purified enzyme was used to study the effect of temperature and pH on enzyme activity and stability, and the inhibitory effect by metal ion on enzyme activity. This thermostable glycogen branching enzyme was found to be most active at 55 °C, and the half-life at 60 °C and 70 °C was 24 h and 5 h, respectively. From this research, a thermostable glycogen branching enzyme was successfully isolated from Geobacillus mahadia Geo-05 by genome mining together with molecular biology technique.

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...

Simulation of the kinetics of enzymic hydrolysis of starch in standard apparatus used in alcohol production

Energy Technology Data Exchange (ETDEWEB)

Rovinskii, L A; Yarovenko, V L

1977-01-01

A mathematical model is described for kinetics of enzymic hydrolysis of starch in standard apparatus used in alcohol fermentation. The apparatus with uniform mixing and displacement was highly superior compared with other apparatuses. Differences of temperature with the apparatus significantly affects the rate of starch hydrolysis compared with constant temperature.

Branching enzyme assay: selective quantitation of the alpha 1,6-linked glucosyl residues involved in the branching points.

Science.gov (United States)

Krisman, C R; Tolmasky, D S; Raffo, S

1985-06-01

Methods previously described for glycogen or amylopectin branching enzymatic activity are insufficiently sensitive and not quantitative. A new, more sensitive, specific, and quantitative one was developed. It is based upon the quantitation of the glucose residues joined by alpha 1,6 bonds introduced by varying amounts of branching enzyme. The procedure involved the synthesis of a polysaccharide from Glc-1-P and phosphorylase in the presence of the sample to be tested. The branched polysaccharide was then purified and the glucoses involved in the branching points were quantitated after degradation with phosphorylase and debranching enzymes. This method appeared to be useful, not only in enzymatic activity determinations but also in the study of the structure of alpha-D-glucans when combined with those of total polysaccharide quantitation, such as iodine and phenol-sulfuric acid.

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.

Lytic polysaccharide monooxygenases and other oxidative enzymes are abundantly secreted by Aspergillus nidulans grown on different starches

DEFF Research Database (Denmark)

Nekiunaite, Laura; Arntzen, Magnus Ø.; Svensson, Birte

2016-01-01

of Aspergillus nidulans grown on cereal starches from wheat and high-amylose (HA) maize, as well as legume starch from pea for 5 days. Aspergillus nidulans grew efficiently on cereal starches, whereas growth on pea starch was poor. The secretomes at days 3-5 were starch-type dependent as also reflected...... by amylolytic activity measurements. Nearly half of the 312 proteins in the secretomes were carbohydrate-active enzymes (CAZymes), mostly glycoside hydrolases (GHs) and oxidative auxiliary activities (AAs). The abundance of the GH13 α-amylase (AmyB) decreased with time, as opposed to other starch...

Modelling the Effects of Ageing Time of Starch on the Enzymatic Activity of Three Amylolytic Enzymes

Science.gov (United States)

Guerra, Nelson P.; Pastrana Castro, Lorenzo

2012-01-01

The effect of increasing ageing time (t) of starch on the activity of three amylolytic enzymes (Termamyl, San Super, and BAN) was investigated. Although all the enzymatic reactions follow michaelian kinetics, v max decreased significantly (P enzymes and the release of the reaction products to the medium. A similar effect was observed when the enzymatic reactions were carried out with unaged starches supplemented with different concentrations of gelatine [G]. The inhibition in the amylolytic activities was best mathematically described by using three modified forms of the Michaelis-Menten model, which included a term to consider, respectively, the linear, exponential, and hyperbolic inhibitory effects of t and [G]. PMID:22666116

Utilization of α-amylase enzyme from Bacillus stearothermophilus RSAII1B for maltodextrin production from sago starch

Science.gov (United States)

Arfah, R. A.; Ahmad, A.; Dali, S.; Djide, M. N.; Mahdalia; Arif, A. R.

2018-03-01

The dried sago flour derived from Palopo contains 28.80% amylose and 91.23% total carbohydrate. Based on the data, sago starch has the potential to become an alternative raw material for themaltodextrin production. Maltodextrin is one of the starch derivative products produced by hydrolysis process using the α-amylase enzyme with amaximum DE (dextrose equivalent) value of 20. The use of maltodextrin for food and pharmaceutical industries is increasing because of maltodextrin is widely used as thickener filler, surfactant and sugar substitute in milk powder. The aims of this study are to optimize the addition of enzyme concentration and hydrolysis time of α -amylase enzyme to obtain high quality ofmaltodextrin This study also aimed to characterization the obtained maltodextrin. The first step was isolation and purification α-amylase from the isolate of Bacillus stearothermophilus RSAII1B, followed by determination of the α-amylase concentration (0.05%, 0.07% and 0.09%) in 2.0% starch substrate, and the hydrolysis time ofα-amilase (60, 90, 120, 240 minutes). Maltodextrin characters observed were dextrose equivalent (DE), reducing sugar, moisture content, pH changes, color, solubility, viscosity, and total plate count (TPC). The results showed that the value of DE was 12.31, reducing sugar was 11.4%; water content was 10.92%; pH was 4.85; The color of maltodextrin powder was white bone color; solubility was 153.2 g/L; Viscositywas 210-240 cps, TPCwas 380 cfu/g. Maltodextrins produced from sago starch using the α-amylase enzyme from B.stearothermophillus RSAIIm met the quality requirements of SNI 7599: 2010.

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.

Impact of amylosucrase modification on the structural and physicochemical properties of native and acid-thinned waxy corn starch.

Science.gov (United States)

Zhang, Hao; Zhou, Xing; He, Jian; Wang, Tao; Luo, Xiaohu; Wang, Li; Wang, Ren; Chen, Zhengxing

2017-04-01

Recombinant amylosucrase from Neisseria polysaccharea was utilized to modify native and acid-thinned starches. The molecular structures and physicochemical properties of modified starches were investigated. Acid-thinned starch displayed much lower viscosity after gelatinization than did the native starch. However, the enzyme exhibited similar catalytic efficiency for both forms of starch. The modified starches had higher proportions of long (DP>33) and intermediate chains (DP 13-33), and X-ray diffraction showed a B-type crystalline structure for all modified starches. With increasing reaction time, the relative crystallinity and endothermic enthalpy of the modified starches gradually decreased, whereas the melting peak temperatures and resistant starch contents increased. Slight differences were observed in thermal parameters, relative crystallinity, and branch chain length distribution between the modified native and acid-thinned starches. Moreover, the digestibility of the modified starches was not affected by acid hydrolysis pretreatment, but was affected by the percentage of intermediate and long chains. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterizations of substrate and enzyme specificity of glucoamylase assays of mucosal starch digestion with determinations of group and single biopsy reference values

Science.gov (United States)

Carbohydrate digesting enzyme activities are measured in duodenal biopsies to detect deficiencies of lactase and sucrase activities, however glucoamylase (GA) assays for starch digestion are not included. Because food starch represents half of energy intake in the human diet, assays for starch diges...

The Conversion of Starch and Sugars into Branched C10 and C11 Hydrocarbons.

Science.gov (United States)

Sutton, Andrew D; Kim, Jin K; Wu, Ruilian; Hoyt, Caroline B; Kimball, David B; Silks, Louis A; Gordon, John C

2016-09-08

Oligosaccharides, such as starch, cellulose, and hemicelluloses, are abundant and easily obtainable bio-derived materials that can potentially be used as precursors for fuels and chemical feedstocks. To access the pertinent molecular building blocks (i.e., 5- or 6-carbon containing sugar units) located within these biopolymers and transform them into useful fuel precursors, oligosaccharide depolymerization followed by chain extension is required. This chain extension can readily be performed via a Garcia-Gonzalez-like approach using β-diketones under mild conditions to provide fuel precursors containing an increased carbon atom content that meets fuel requirements. In a subsequent step, ring opening and hydrodeoxygenation chemistry of these species allows for the preparation of branched alkanes under relatively mild conditions. This approach can be applied to monomeric sugars (glucose and xylose), oligosaccharides (starch), and potentially to hydrolyzed dedicated energy crops to allow the conversion of real biomass into fuel type molecules. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of starch nanoparticles

Science.gov (United States)

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

2009-01-01

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

Starch 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.

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

Detoxification of corn stover and corn starch pyrolysis liquors by ligninolytic enzymes of Phanerochaete chrysosporium.

Science.gov (United States)

Khiyami, Mohammad A; Pometto, Anthony L; Brown, Robert C

2005-04-20

Phanerochaete chrysosporium (ATCC 24725) shake flask culture with 3 mM veratryl alcohol addition on day 3 was able to grow and detoxify different concentrations of diluted corn stover (Dcs) and diluted corn starch (Dst) pyrolysis liquors [10, 25, and 50% (v/v)] in defined media. GC-MS analysis of reaction products showed a decrease and change in some compounds. In addition, the total phenolic assay with Dcs samples demonstrated a decrease in the phenolic compounds. A bioassay employing Lactobacillus casei growth and lactic acid production was developed to confirm the removal of toxic compounds from 10 and 25% (v/v) Dcs and Dst by the lignolytic enzymes, but not from 50% (v/v) Dcs and Dst. The removal did not occur when sodium azide or cycloheximide was added to Ph. chrysosporium culture media, confirming the participation of lignolytic enzymes in the detoxification process. A concentrated enzyme preparation decreased the phenolic compounds in 10% (v/v) corn stover and corn starch pyrolysis liquors to the same extent as the fungal cultures.

An extracellular cell-attached pullulanase confers branched α-glucan utilization in human gut Lactobacillus acidophilus

DEFF Research Database (Denmark)

Møller, Marie Sofie; Goh, Yong Jun; Rasmussen, Kasper Bøwig

2017-01-01

binding modules, a domain of unknown function, and a C-terminal surface layer association protein (SLAP) domain. Here we explore the specificity of a representative of this group of pullulanases, LaPul13_14 and its role in branched α-glucans metabolism in the well characterized Lactobacillus acidophilus...... in the presence of α-glucans but was repressed by glucose. The debranching activity is conferred exclusively by LaPul13_14 and is abolished in a mutant strain lacking a functional LaPul13_14 gene. Hydrolysis kinetics of recombinant LaPul13_14 confirmed the preference for short branched α-glucan oligomers....... Branched α-1,6-glucans in dietary starch and glycogen are non-degradable by human enzymes and constitute a metabolic resource for the gut microbiota. The role of health-beneficial lactobacilli prevalent in the human small intestine in starch metabolism remains unexplored in contrast to colonic bacterial...

Physical structure and absorption properties of tailor-made porous starch granules produced by selected amylolytic enzymes.

Directory of Open Access Journals (Sweden)

Yi-Seul Jung

Full Text Available Porous starch granules (PSGs with various pores and cavity sizes were prepared by amylolysis enzymes. The greatest hydrolysis rate on corn starch granule was observed with α-amylase, followed by gluco- and β-amylases. Temperature increase enhanced glucoamylase reaction rate more drastically than other enzyme treatments. Final hydrolysis level with glucoamylase reached to 66.9%, close to 67.5% of α-amylolysis. The α-amylase-treated PSGs displayed the greatest pore size and ratio of cavity-to-granule diameters. Gelatinization onset temperatures of PSGs increased to 72.1 (α-, 68.7 (β-, and 68.1°C (gluco-amylolysis after 8 h; enthalpy changes of β- and gluco-amylase-treated PSGs increased to 13.4, and 13.1 J/g but α-amylase-treated one showed slightly reduced value of 8.5 J/g. Water holding capacities of PSGs were 209.7 (α-, 94.6 (β-, and 133.8% (gluco-amylolysis, and the untreated control had 89.1%; oil holding capacities of them showed 304.5, 182.7, and 211.5%, respectively, while the untreated control had 161.8%. Thus, enzyme types and their reaction conditions can be applied to generate desirable cavity and pore sizes in starch granules. This biocatalytic approach could contribute to develop tailor-made PSGs with distinct internal structure for specific uses in wide range of food, pharmaceutical and other industrial applications.

Physical structure and absorption properties of tailor-made porous starch granules produced by selected amylolytic enzymes

Science.gov (United States)

Jung, Yi-seul; Lee, Byung-Hoo

2017-01-01

Porous starch granules (PSGs) with various pores and cavity sizes were prepared by amylolysis enzymes. The greatest hydrolysis rate on corn starch granule was observed with α-amylase, followed by gluco- and β-amylases. Temperature increase enhanced glucoamylase reaction rate more drastically than other enzyme treatments. Final hydrolysis level with glucoamylase reached to 66.9%, close to 67.5% of α-amylolysis. The α-amylase-treated PSGs displayed the greatest pore size and ratio of cavity-to-granule diameters. Gelatinization onset temperatures of PSGs increased to 72.1 (α-), 68.7 (β-), and 68.1°C (gluco-amylolysis) after 8 h; enthalpy changes of β- and gluco-amylase-treated PSGs increased to 13.4, and 13.1 J/g but α-amylase-treated one showed slightly reduced value of 8.5 J/g. Water holding capacities of PSGs were 209.7 (α-), 94.6 (β-), and 133.8% (gluco-amylolysis), and the untreated control had 89.1%; oil holding capacities of them showed 304.5, 182.7, and 211.5%, respectively, while the untreated control had 161.8%. Thus, enzyme types and their reaction conditions can be applied to generate desirable cavity and pore sizes in starch granules. This biocatalytic approach could contribute to develop tailor-made PSGs with distinct internal structure for specific uses in wide range of food, pharmaceutical and other industrial applications. PMID:28727742

Production of raw starch-degrading enzyme by Aspergillus sp. and its use in conversion of inedible wild cassava flour to bioethanol.

Science.gov (United States)

Moshi, Anselm P; Hosea, Ken M M; Elisante, Emrode; Mamo, Gashaw; Önnby, Linda; Nges, Ivo Achu

2016-04-01

The major bottlenecks in achieving competitive bioethanol fuel are the high cost of feedstock, energy and enzymes employed in pretreatment prior to fermentation. Lignocellulosic biomass has been proposed as an alternative feedstock, but because of its complexity, economic viability is yet to be realized. Therefore, research around non-conventional feedstocks and deployment of bioconversion approaches that downsize the cost of energy and enzymes is justified. In this study, a non-conventional feedstock, inedible wild cassava was used for bioethanol production. Bioconversion of raw starch from the wild cassava to bioethanol at low temperature was investigated using both a co-culture of Aspergillus sp. and Saccharomyces cerevisiae, and a monoculture of the later with enzyme preparation from the former. A newly isolated strain of Aspergillus sp. MZA-3 produced raw starch-degrading enzyme which displayed highest activity of 3.3 U/mL towards raw starch from wild cassava at 50°C, pH 5.5. A co-culture of MZA-3 and S. cerevisiae; and a monoculture of S. cerevisiae and MZA-3 enzyme (both supplemented with glucoamylase) resulted into bioethanol yield (percentage of the theoretical yield) of 91 and 95 at efficiency (percentage) of 84 and 96, respectively. Direct bioconversion of raw starch to bioethanol was achieved at 30°C through the co-culture approach. This could be attractive since it may significantly downsize energy expenses. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

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.

Production of raw cassava starch-degrading enzyme by Penicillium and its use in conversion of raw cassava flour to ethanol.

Science.gov (United States)

Lin, Hai-Juan; Xian, Liang; Zhang, Qiu-Jiang; Luo, Xue-Mei; Xu, Qiang-Sheng; Yang, Qi; Duan, Cheng-Jie; Liu, Jun-Liang; Tang, Ji-Liang; Feng, Jia-Xun

2011-06-01

A newly isolated strain Penicillium sp. GXU20 produced a raw starch-degrading enzyme which showed optimum activity towards raw cassava starch at pH 4.5 and 50 °C. Maximum raw cassava starch-degrading enzyme (RCSDE) activity of 20 U/ml was achieved when GXU20 was cultivated under optimized conditions using wheat bran (3.0% w/v) and soybean meal (2.5% w/v) as carbon and nitrogen sources at pH 5.0 and 28 °C. This represented about a sixfold increment as compared with the activity obtained under basal conditions. Starch hydrolysis degree of 95% of raw cassava flour (150 g/l) was achieved after 72 h of digestion by crude RCSDE (30 U/g flour). Ethanol yield reached 53.3 g/l with fermentation efficiency of 92% after 48 h of simultaneous saccharification and fermentation of raw cassava flour at 150 g/l using the RCSDE (30 U/g flour), carried out at pH 4.0 and 40 °C. This strain and its RCSDE have potential applications in processing of raw cassava starch to ethanol.

Structure, function and protein engineering in starch debranching enzyme systems. Barley limit dextrinase and its endogenous inhibitor

DEFF Research Database (Denmark)

Møller, Marie Sofie

Starch is the most abundant storage carbohydrate in cereal grains. It is composed primarily of amylopectin, a polymer of glucose in which α-1,4-linked glucan chains are branched with α-1,6-bonds. Enzymatic degradation of starch in germinating barley seeds involves an initial solubilisation, mainly...... in a hydrophobic cluster of LDI caused the most dramatic decreases in binding affinity. The LDI-L41G-V42D variant had close to 5×105-fold reduced affinity. The complex formation was independent of ionic strength, which was confirmed by the minor importance of two LDI arginines, Arg34 and Arg38, for the binding...

Changes in Enzyme Activities Involved in Starch Synthesis and Hormone Concentrations in Superior and Inferior Spikelets and Their Association with Grain Filling of Super Rice

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Jing FU

2013-03-01

Full Text Available The changes in activities of key enzymes involved in sucrose-to-starch conversion and concentrations of hormones in superior and inferior spikelets of super rice were investigated and their association with grain filling was analyzed. Four super rice cultivars, Liangyoupeijiu, IIyou 084, Huaidao 9 and Wujing 15, and two high-yielding and elite check cultivars, Shanyou 63 and Yangfujing 8, were used. The activities of sucrose synthase (SuSase, adenosine diphosphoglucose pyrophosphorylase (AGPase, starch synthase (StSase and starch branching enzyme (SBE, and the concentrations of zeatin + zeatin riboside (Z + ZR, indole-3-acetic acid (IAA and abscisic acid (ABA in superior and inferior spikelets were determined during the grain filling period and their relationships with grain filling rate were analyzed. Maximum grain filling rate, the time reaching the maximum grain-filling rate, mean grain filling rate and brown rice weight for superior spikelets showed a slight difference between the super and check rice cultivars, but were significantly lower in the super rice than in the check rice for inferior spikelets. Changes of enzyme activities and hormone concentrations in grains exhibited single peak curves during the grain filling period. The peak values and the mean activities of SuSase, AGPase, StSase and SBE were lower in inferior spikelets than in superior ones, as well as the peak values and the mean concentrations of Z + ZR and IAA. However, the peak value and the mean concentration of ABA were significantly higher in inferior spikelets than in superior ones and greater in the super rice than in the check rice. The grain filling rate was positively and significantly correlated with the activities of SuSase, AGPase and StSase and the concentrations of Z + ZR and IAA. The results suggested that the low activities of SuSase, AGPase and StSase and the low concentrations of Z + ZR and IAA might be important physiological reasons for the slow grain

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

NARCIS (Netherlands)

Gangoiti, Joana; Pijning, Tjaard; Dijkhuizen, Lubbert

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

Sugarcane starch: quantitative determination and characterization

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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.

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...

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.

Effects of microbial enzymes on starch and hemicellulose degradation in total mixed ration silages

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Tingting Ning

2017-02-01

Full Text Available Objective This study investigated the association of enzyme-producing microbes and their enzymes with starch and hemicellulose degradation during fermentation of total mixed ration (TMR silage. Methods The TMRs were prepared with soybean curd residue, alfalfa hay (ATMR or Leymus chinensis hay (LTMR, corn meal, soybean meal, vitamin-mineral supplements, and salt at a ratio of 25:40:30:4:0.5:0.5 on a dry matter basis. Laboratory-scale bag silos were randomly opened after 1, 3, 7, 14, 28, and 56 days of ensiling and subjected to analyses of fermentation quality, carbohydrates loss, microbial amylase and hemicellulase activities, succession of dominant amylolytic or hemicellulolytic microbes, and their microbial and enzymatic properties. Results Both ATMR and LTMR silages were well preserved, with low pH and high lactic acid concentrations. In addition to the substantial loss of water soluble carbohydrates, loss of starch and hemicellulose was also observed in both TMR silages with prolonged ensiling. The microbial amylase activity remained detectable throughout the ensiling in both TMR silages, whereas the microbial hemicellulase activity progressively decreased until it was inactive at day 14 post-ensiling in both TMR silages. During the early stage of fermentation, the main amylase-producing microbes were Bacillus amyloliquefaciens (B. amyloliquefaciens, B. cereus, B. licheniformis, and B. subtilis in ATMR silage and B. flexus, B. licheniformis, and Paenibacillus xylanexedens (P. xylanexedens in LTMR silage, whereas Enterococcus faecium was closely associated with starch hydrolysis at the later stage of fermentation in both TMR silages. B. amyloliquefaciens, B. licheniformis, and B. subtilis and B. licheniformis, B. pumilus, and P. xylanexedens were the main source of microbial hemicellulase during the early stage of fermentation in ATMR and LTMR silages, respectively. Conclusion The microbial amylase contributes to starch hydrolysis during the

Polymeric amylase nanoparticles as a new semi-synthetic enzyme system for hydrolysis of starch

International Nuclear Information System (INIS)

Say, R.; Şenay, R. Hilal; Biçen, Özlem; Ersöz, Arzu; Şişman Yılmaz, Filiz; Akgöl, Sinan; Denizli, Adil

2013-01-01

α-Amylase (EC 3.2.1.1; α-D-1,4,glucan glucanohydrolase) catalyzes the hydrolysis of α-D-(1,4)-glucosidic linkages in starch, glycogen, and various malto-oligosaccharides, by releasing α-anomeric products. In this study, a novel method has been developed to prepare nanoprotein particles that carry α-amylase as a monomer by using a photosensitive microemulsion polymerization process. The nanostructured α-amylase with photosensitive features have been characterized by fluorescence spectroscopy, transmission electron microscopy (TEM) and Zeta Sizer. The fluorescence intensity of amylase nanoparticles was determined to be 658 a.u. at 610 nm and the average particle size of nanoamylase was found to be about 71.8 nm. Both free α-amylase and nanoparticles were used in the hydrolysis of starch under varying reaction conditions such as pH and temperature that affect enzyme activity and the results were compared to each other. K m values were 0.26 and 0.87 mM and V max values were 0.36 IU mg −1 and 22.32 IU mg −1 for nanoenzyme and free enzyme, respectively. Then, thermal stability, storage stability and reusability were investigated and according to the results, activity was preserved 60% at 60 °C; 20% at 70–80 °C temperature values and 80% after 105 days storage. Finally after 10 cycles, the activity was preserved 90% and this novel enzymatic polymeric amylase nanoparticle has showed considerable potential as reusable catalyst. - Highlights: ► Developing to prepare nanoprotein particles carrying α-amylase ► Characterization of nanostructured α-amylase ► Usability of α-amylase nanoparticles in hydrolysis of starch

Polymeric amylase nanoparticles as a new semi-synthetic enzyme system for hydrolysis of starch

Energy Technology Data Exchange (ETDEWEB)

Say, R. [Anadolu University, Faculty of Science, Chemistry Department, Yunus Emre Campus, Eskişehir (Turkey); Şenay, R. Hilal [Ege University, Faculty of Science, Biochemistry Department, 35100 Bornova-Izmir (Turkey); Biçen, Özlem; Ersöz, Arzu; Şişman Yılmaz, Filiz [Anadolu University, Faculty of Science, Chemistry Department, Yunus Emre Campus, Eskişehir (Turkey); Akgöl, Sinan, E-mail: sinanakgol@yahoo.co.uk [Ege University, Faculty of Science, Biochemistry Department, 35100 Bornova-Izmir (Turkey); Denizli, Adil [Hacettepe University, Faculty of Science, Chemistry Department, 06532 Ankara (Turkey)

2013-05-01

α-Amylase (EC 3.2.1.1; α-D-1,4,glucan glucanohydrolase) catalyzes the hydrolysis of α-D-(1,4)-glucosidic linkages in starch, glycogen, and various malto-oligosaccharides, by releasing α-anomeric products. In this study, a novel method has been developed to prepare nanoprotein particles that carry α-amylase as a monomer by using a photosensitive microemulsion polymerization process. The nanostructured α-amylase with photosensitive features have been characterized by fluorescence spectroscopy, transmission electron microscopy (TEM) and Zeta Sizer. The fluorescence intensity of amylase nanoparticles was determined to be 658 a.u. at 610 nm and the average particle size of nanoamylase was found to be about 71.8 nm. Both free α-amylase and nanoparticles were used in the hydrolysis of starch under varying reaction conditions such as pH and temperature that affect enzyme activity and the results were compared to each other. K{sub m} values were 0.26 and 0.87 mM and V{sub max} values were 0.36 IU mg{sup −1} and 22.32 IU mg{sup −1} for nanoenzyme and free enzyme, respectively. Then, thermal stability, storage stability and reusability were investigated and according to the results, activity was preserved 60% at 60 °C; 20% at 70–80 °C temperature values and 80% after 105 days storage. Finally after 10 cycles, the activity was preserved 90% and this novel enzymatic polymeric amylase nanoparticle has showed considerable potential as reusable catalyst. - Highlights: ► Developing to prepare nanoprotein particles carrying α-amylase ► Characterization of nanostructured α-amylase ► Usability of α-amylase nanoparticles in hydrolysis of starch.

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.

Determination Of Enzyme Kinetic Parameters on Sago Starch Hydrolysis By Linearized Graphical Methods

International Nuclear Information System (INIS)

Lai, L.W.; Teo, C.L.; Suzana Wahidin; Mohamad Suffian Mohamad Annuar

2014-01-01

Amyloglucosidase (E.C. 3.2.1.3) from Aspergillus niger was used to hydrolyze the sago (Metro xylon sagu) starch into reducing sugars. The experiment was conducted at constant temperature, 55 degree Celsius; pH, 4.5 and enzyme amount, 0.2 U/ ml, respectively. In this investigation, the substrate concentration was varied ranging from 1.0 - 7.0 g/ L. The obtained data were then fixed into linearized plots namely Lineweaver-Burk and Langmuir models to calculate enzyme kinetic parameters, K m and V max . Both of the K m and V max (mM, mol/min) values from each plot were: Lineweaver-Burk (26.53, 3.31) and Langmuir (13.52, 2.35). Among the linearized models, K m and V max values acquired from Langmuir plot was chosen. (author)

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...

Immobilization of urease on grafted starch by radiation method

International Nuclear Information System (INIS)

Nguyenanh Dung; Nguyendinh Huyen

1995-01-01

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

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.

Enhanced production of raw starch degrading enzyme using agro-industrial waste mixtures by thermotolerant Rhizopus microsporus for raw cassava chip saccharification in ethanol production.

Science.gov (United States)

Trakarnpaiboon, Srisakul; Srisuk, Nantana; Piyachomkwan, Kuakoon; Sakai, Kenji; Kitpreechavanich, Vichien

2017-09-14

In the present study, solid-state fermentation for the production of raw starch degrading enzyme was investigated by thermotolerant Rhizopus microsporus TISTR 3531 using a combination of agro-industrial wastes as substrates. The obtained crude enzyme was applied for hydrolysis of raw cassava starch and chips at low temperature and subjected to nonsterile ethanol production using raw cassava chips. The agro-industrial waste ratio was optimized using a simplex axial mixture design. The results showed that the substrate mixture consisting of rice bran:corncob:cassava bagasse at 8 g:10 g:2 g yielded the highest enzyme production of 201.6 U/g dry solid. The optimized condition for solid-state fermentation was found as 65% initial moisture content, 35°C, initial pH of 6.0, and 5 × 10 6 spores/mL inoculum, which gave the highest enzyme activity of 389.5 U/g dry solid. The enzyme showed high efficiency on saccharification of raw cassava starch and chips with synergistic activities of commercial α-amylase at 50°C, which promotes low-temperature bioethanol production. A high ethanol concentration of 102.2 g/L with 78% fermentation efficiency was achieved from modified simultaneous saccharification and fermentation using cofermentation of the enzymatic hydrolysate of 300 g raw cassava chips/L with cane molasses.

Strategies for enzyme saving during saccharification of pretreated lignocellulo-starch biomass: effect of enzyme dosage and detoxification chemicals

Directory of Open Access Journals (Sweden)

M.G. Mithra

2017-08-01

Full Text Available Two strategies leading to enzyme saving during saccharification of pretreated lignocellulo-starch biomass (LCSB was investigated which included reducing enzyme dosage by varying their levels in enzyme cocktails and enhancing the fermentable sugar yield in enzyme-reduced systems using detoxification chemicals. Time course release of reducing sugars (RS during 24–120 h was significantly higher when an enzyme cocktail containing full dose of cellulase (16 FPU/g cellulose along with half dose each of xylanase (1.5 mg protein/g hemicelluloses and Stargen (12.5 μl/g biomass was used to saccharify conventional dilute sulphuric acid (DSA pretreated biomass compared to a parallel system where only one-fourth the dose of the latter two enzymes was used. The reduction in RS content in the 120 h saccharified mash to the extent of 3–4 g/L compared to the system saccharified with full complement of the three enzymes could be overcome considerably by supplementing the system (half dose of two enzymes with detoxification chemical mix incorporating Tween 20, PEG 4000 and sodium borohydride. Microwave (MW-assisted DSA pretreated biomass on saccharification with enzyme cocktail having full dose of cellulase and half dose of Stargen along with detoxification chemicals gave significantly higher RS yield than DSA pretreated system saccharified using three enzymes. The study showed that xylanase could be eliminated during saccharification of MW-assisted DSA pretreated biomass without affecting RS yield when detoxification chemicals were also supplemented. The Saccharification Efficiency and Overall Conversion Efficiency were also high for the MW-assisted DSA pretreated biomass. Since whole slurry saccharifcation of pretreated biomass is essential to conserve fermentable sugars in LCSB saccharification, detoxification of soluble inhibitors is equally important as channelling out of insoluble lignin remaining in the residue. As one of the major factors contributing

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...

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.

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

Science.gov (United States)

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

2013-01-01

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

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

Directory of Open Access Journals (Sweden)

Sushil Dhital

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

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

Science.gov (United States)

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

2013-01-01

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

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.

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

Crystal Structure of Full-length Mycobacterium tuberculosis H37Rv Glycogen Branching Enzyme; Insights of N-Terminal [beta]-Sandwich in Sustrate Specifity and Enzymatic Activity

Energy Technology Data Exchange (ETDEWEB)

Pal, Kuntal; Kumar, Shiva; Sharma, Shikha; Garg, Saurabh Kumar; Alam, Mohammad Suhail; Xu, H. Eric; Agrawal, Pushpa; Swaminathan, Kunchithapadam (NU Sinapore); (Van Andel); (IMT-India)

2010-07-13

The open reading frame Rv1326c of Mycobacterium tuberculosis (Mtb) H37Rv encodes for an {alpha}-1,4-glucan branching enzyme (MtbGlgB, EC 2.4.1.18, Uniprot entry Q10625). This enzyme belongs to glycoside hydrolase (GH) family 13 and catalyzes the branching of a linear glucose chain during glycogenesis by cleaving a 1 {yields} 4 bond and making a new 1 {yields} 6 bond. Here, we show the crystal structure of full-length MtbGlgB (MtbGlgBWT) at 2.33-{angstrom} resolution. MtbGlgBWT contains four domains: N1 {beta}-sandwich, N2 {beta}-sandwich, a central ({beta}/{alpha}){sub 8} domain that houses the catalytic site, and a C-terminal {beta}-sandwich. We have assayed the amylase activity with amylose and starch as substrates and the glycogen branching activity using amylose as a substrate for MtbGlgBWT and the N1 domain-deleted (the first 108 residues deleted) Mtb{Delta}108GlgB protein. The N1 {beta}-sandwich, which is formed by the first 105 amino acids and superimposes well with the N2 {beta}-sandwich, is shown to have an influence in substrate binding in the amylase assay. Also, we have checked and shown that several GH13 family inhibitors are ineffective against MtbGlgBWT and Mtb{Delta}108GlgB. We propose a two-step reaction mechanism, for the amylase activity (1 {yields} 4 bond breakage) and isomerization (1 {yields} 6 bond formation), which occurs in the same catalytic pocket. The structural and functional properties of MtbGlgB and Mtb{Delta}108GlgB are compared with those of the N-terminal 112-amino acid-deleted Escherichia coli GlgB (EC{Delta}112GlgB).

Polymeric amylase nanoparticles as a new semi-synthetic enzyme system for hydrolysis of starch.

Science.gov (United States)

Say, R; Şenay, R Hilal; Biçen, Özlem; Ersöz, Arzu; Şişman Yılmaz, Filiz; Akgöl, Sinan; Denizli, Adil

2013-05-01

α-Amylase (EC 3.2.1.1; α-D-1,4,glucan glucanohydrolase) catalyzes the hydrolysis of α-D-(1,4)-glucosidic linkages in starch, glycogen, and various malto-oligosaccharides, by releasing α-anomeric products. In this study, a novel method has been developed to prepare nanoprotein particles that carry α-amylase as a monomer by using a photosensitive microemulsion polymerization process. The nanostructured α-amylase with photosensitive features have been characterized by fluorescence spectroscopy, transmission electron microscopy (TEM) and Zeta Sizer. The fluorescence intensity of amylase nanoparticles was determined to be 658 a.u. at 610 nm and the average particle size of nanoamylase was found to be about 71.8 nm. Both free α-amylase and nanoparticles were used in the hydrolysis of starch under varying reaction conditions such as pH and temperature that affect enzyme activity and the results were compared to each other. Km values were 0.26 and 0.87 mM and Vmax values were 0.36 IU mg(-1) and 22.32 IU mg(-1) for nanoenzyme and free enzyme, respectively. Then, thermal stability, storage stability and reusability were investigated and according to the results, activity was preserved 60% at 60 °C; 20% at 70-80 °C temperature values and 80% after 105 days storage. Finally after 10 cycles, the activity was preserved 90% and this novel enzymatic polymeric amylase nanoparticle has showed considerable potential as reusable catalyst. Copyright © 2012 Elsevier B.V. All rights reserved.

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

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®

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

Science.gov (United States)

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

2014-01-01

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

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

Directory of Open Access Journals (Sweden)

Alex Chi Wu

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

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.

Biochemical Characterization of the Lactobacillus reuteri Glycoside Hydrolase Family 70 GTFB Type of 4,6-α-Glucanotransferase Enzymes That Synthesize Soluble Dietary Starch Fibers.

Science.gov (United States)

Bai, Yuxiang; van der Kaaij, Rachel Maria; Leemhuis, Hans; Pijning, Tjaard; van Leeuwen, Sander Sebastiaan; Jin, Zhengyu; Dijkhuizen, Lubbert

2015-10-01

4,6-α-Glucanotransferase (4,6-α-GTase) enzymes, such as GTFB and GTFW of Lactobacillus reuteri strains, constitute a new reaction specificity in glycoside hydrolase family 70 (GH70) and are novel enzymes that convert starch or starch hydrolysates into isomalto/maltopolysaccharides (IMMPs). These IMMPs still have linear chains with some α1→4 linkages but mostly (relatively long) linear chains with α1→6 linkages and are soluble dietary starch fibers. 4,6-α-GTase enzymes and their products have significant potential for industrial applications. Here we report that an N-terminal truncation (amino acids 1 to 733) strongly enhances the soluble expression level of fully active GTFB-ΔN (approximately 75-fold compared to full-length wild type GTFB) in Escherichia coli. In addition, quantitative assays based on amylose V as the substrate are described; these assays allow accurate determination of both hydrolysis (minor) activity (glucose release, reducing power) and total activity (iodine staining) and calculation of the transferase (major) activity of these 4,6-α-GTase enzymes. The data show that GTFB-ΔN is clearly less hydrolytic than GTFW, which is also supported by nuclear magnetic resonance (NMR) analysis of their final products. From these assays, the biochemical properties of GTFB-ΔN were characterized in detail, including determination of kinetic parameters and acceptor substrate specificity. The GTFB enzyme displayed high conversion yields at relatively high substrate concentrations, a promising feature for industrial application. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Early-branching Gut Fungi Possess A Large, And Comprehensive Array Of Biomass-Degrading Enzymes

Energy Technology Data Exchange (ETDEWEB)

Solomon, Kevin V.; Haitjema, Charles; Henske, John K.; Gilmore, Sean P.; Borges-Rivera, Diego; Lipzen, Anna; Brewer, Heather M.; Purvine, Samuel O.; Wright, Aaron T.; Theodorou, Michael K.; Grigoriev, Igor V.; Regev, Aviv; Thompson, Dawn; O' Malley, Michelle A.

2016-03-11

The fungal kingdom is the source of almost all industrial enzymes in use for lignocellulose bioprocessing. Its more primitive members, however, remain relatively unexploited. We developed a systems-level approach that integrates RNA-Seq, proteomics, phenotype and biochemical studies of relatively unexplored early-branching free-living fungi. Anaerobic gut fungi isolated from herbivores produce a large array of biomass-degrading enzymes that synergistically degrade crude, unpretreated plant biomass, and are competitive with optimized commercial preparations from Aspergillus and Trichoderma. Compared to these model platforms, gut fungal enzymes are unbiased in substrate preference due to a wealth of xylan-degrading enzymes. These enzymes are universally catabolite repressed, and are further regulated by a rich landscape of noncoding regulatory RNAs. Furthermore, we identified several promising sequence divergent enzyme candidates for lignocellulosic bioprocessing.

Transfer action of cyclodextrin glycosyltransferase on starch

Energy Technology Data Exchange (ETDEWEB)

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

1975-11-01

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

Determination of the starch-phosphorylating enzyme activity in plant extracts

DEFF Research Database (Denmark)

Ritte, G.; Steup, M.; Kossmann, J.

2003-01-01

For quantification of alpha-glucan, water dikinase(GWD) activity in crude extracts of plant tissues a radio-labeling assay was established that uses soluble starch and P-33-labeled ATP as phosphate acceptor and donor, respectively. A constant rate of starch labeling was observed only if the ATP...... incorporation of phosphate whereas extracts from potato (Solanum tuberosum L.) tuber expressing a GWD antisense construct exhibited less activity than the wild-type control. To our knowledge this is the first time that a quantification of the starch-phosphorylating activity has been achieved in plant crude...

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

In Vitro Biochemical Characterization of All Barley Endosperm Starch Synthases

Directory of Open Access Journals (Sweden)

Jose Antonio Cuesta-Seijo

2016-01-01

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

Amylolytic Enzymes Acquired from L-Lactic Acid Producing Enterococcus faecium K-1 and Improvement of Direct Lactic Acid Production from Cassava Starch.

Science.gov (United States)

Unban, Kridsada; Kanpiengjai, Apinun; Takata, Goro; Uechi, Keiko; Lee, Wen-Chien; Khanongnuch, Chartchai

2017-09-01

An amylolytic lactic acid bacterium isolate K-1 was isolated from the wastewater of a cassava starch manufacturing factory and identified as Entercoccus faecium based on 16S rRNA gene sequence analysis. An extracellular α-amylase was purified to homogeneity and the molecular weight of the purified enzyme was approximately 112 kDa with optimal pH value and temperature measured of 7.0 and 40 °C, respectively. It was stable at a pH range of 6.0-7.0, but was markedly sensitive to high temperatures and low pH conditions, even at a pH value of 5. Ba 2+ , Al 3+ , and Co 2+ activated enzyme activity. This bacterium was capable of producing 99.2% high optically pure L-lactic acid of 4.3 and 8.2 g/L under uncontrolled and controlled pH at 6.5 conditions, respectively, in the MRS broth containing 10 g/L cassava starch as the sole carbon source when cultivated at 37 °C for 48 h. A control pH condition of 6.5 improved and stabilized the yield of L-lactic acid production directly from starch even at a high concentration of starch at up to 150 g/L. This paper is the first report describing the properties of purified α-amylase from E. faecium. Additionally, pullulanase and cyclodextrinase activities were also firstly recorded from E. faecium K-1.

Enzymes in biogenesis of plant cell wall polysaccharides. Enzyme characterization using tracer techniques

International Nuclear Information System (INIS)

Dickinson, D.B.

1975-01-01

Enzymes and metabolic pathways, by which starch and cell wall polysaccharides are formed, were investigated in order to learn how these processes are regulated and to identify the enzymatic regulatory mechanisms involved. Germinating lily pollen was used for studies of cell wall formation, and pollen and maize endosperm for studies of starch biosynthesis. Hexokinase being the first step in conversion of hexoses to starch, wall polysaccharides and respiratory substrates, maize endosperm enzyme was assayed by its conversion of 14 C-hexose to 14 C-hexose-6-P, and rapid separation of the two labelled compounds on anion-exchange paper. This enzyme did not appear to be under tight regulation by feed-back inhibition or activation, nor to be severely inhibited by glucose-6-P or activated by citrate. ADP-glucose pyrophosphorylase and other pyrophosphorylases were assayed radiochemically with 14 C-glucose-1-P (forward direction) or 32-PPsub(i) (reverse direction). They showed that the maize endosperm enzyme was activated by the glycolytic intermediates fructose-6-P and 3-phosphoglycerate, and that low levels of the enzyme were present in the high sucrose-low starch mutant named shrunken-2. Under optimal in-vitro assay conditions, the pollen enzyme reacted four times faster than the observed in-vivo rate of starch accumulation. Biogenesis of plant cell wall polysaccharides requires the conversion of hexose phosphates to various sugar nucleotides and utilization of the latter by the appropriate polysaccharide synthetases. Lily pollen possesses a β-1,3-glucan synthetase which is activated up to six-fold by β-linked oligosaccharides. Hence, the in-vivo activity of this enzyme may be modulated by such effector molecules

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.

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.

Improvement of Raw-Starch Digestibility of Amylase from Aspergillus awamori by Gamma Radiation Mutation for Alcohol Production

International Nuclear Information System (INIS)

Kanlayakrit, Werasit; Piadang, Nattayana; Maweang, Metinee

2006-09-01

Aspergillus awamori was induced to mutation by gamma ray to improve raw-starch digestibility of amylase enzyme. Twenty fungal colonies were selected base on and amylase and glucoamylase activities including raw starch digestibility. The result showed that isolate A a(i)-2(16) was the best isolate for raw-starch digestion (65.64 %). It produced extracellular amylase enzyme which showed highest raw-starch digestibility more than wild type about 2 folds. Based on enzymes from solid culture showed activities higher from liquid medium. Therefore solid culture is suitable for fungal enzyme production.

Supplementing enzymes to extruded, soybean based diet improves breakdown of non-starch polysaccharides in rainbow trout (Oncorhynchus mykiss)

DEFF Research Database (Denmark)

Dalsgaard, Anne Johanne Tang; Knudsen, Knud Erik Bach; Verlhac, Viviane

2016-01-01

Plant-based feed ingredients typically contain remnants of dietary fibres [DF; non-starch polysaccharides (NSP) and lignin] that have various antinutritive effects in carnivorous fish. Exogenous enzymes have been shown to improve the apparent digestibility coefficients (ADC) of plant-based diets...... presumably by assisting in the breakdown of NSP. This study examined the effects on NSP degradation when supplementing β-glucanase, xylanase, protease or a mix of the three enzymes to an extruded, juvenile rainbow trout (Oncorhynchus mykiss) diet containing 344 g kg−1 de-hulled, solvent-extracted soybean...... meal (SBM). The NSP content in the non-supplemented control diet and in faecal samples from the dietary treatment groups was analysed to determine the recovery/apparent digestibility of cellulose and total non-cellulosic polysaccharide (T-NCP) sugar monomers. The enzymes had significant, positive...

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.

The effect of high hydrostatic pressure treatment on the molecular structure of starches with different amylose content.

Science.gov (United States)

Szwengiel, Artur; Lewandowicz, Grażyna; Górecki, Adrian R; Błaszczak, Wioletta

2018-02-01

The effect of high hydrostatic pressure processing (650MPa/9min) on molecular mass distribution, and hydrodynamic and structural parameters of amylose (maize, sorghum, Hylon VII) and amylopectin (waxy maize, amaranth) starches was studied. The starches were characterized by high-performance size-exclusion chromatography (HPSEC) equipped with static light scattering and refractive index detectors and by Fourier Transform Infrared (FTIR) spectroscopy. Significant changes were observed in molecular mass distribution of pressurized waxy maize starch. Changes in branches/branch frequency, intrinsic viscosity, and radius of gyration were observed for all treated starches. The combination of SEC and FTIR data showed that α-1,6-glycosidic bonds are more frequently split in pressurized amaranth, Hylon VII, and waxy maize starch, while in sorghum and maize starches, the α-1,4 bonds are most commonly split. Our results show that the structural changes found for pressurized starches were more strongly determined by the starch origin than by the processing applied. Copyright © 2017 Elsevier Ltd. All rights reserved.

Properties and applications of starch-converting enzymes of the α-amylase family

NARCIS (Netherlands)

Maarel, Marc J.E.C. van der; Veen, Bart van der; Uitdehaag, Joost C.M.; Leemhuis, Hans; Dijkhuizen, L.

2002-01-01

Starch is a major storage product of many economically important crops such as wheat, rice, maize, tapioca, and potato. A large-scale starch processing industry has emerged in the last century. In the past decades, we have seen a shift from the acid hydrolysis of starch to the use of

Properties and applications of starch-converting enzymes of the alpha-amylase family

NARCIS (Netherlands)

van der Maarel, MJEC; van der Veen, B; Uitdehaag, JCM; Leemhuis, H; Dijkhuizen, L

2002-01-01

Starch is a major storage product of many economically important crops such as wheat, rice, maize, tapioca, and potato. A large-scale starch processing industry has emerged in the last century. In the past decades, we have seen a shift from the acid hydrolysis of starch to the use of

In vitro utilization of amylopectin and high-amylose maize (Amylomaize) starch granules by human colonic bacteria.

Science.gov (United States)

Wang, X; Conway, P L; Brown, I L; Evans, A J

1999-11-01

It has been well established that a certain amount of ingested starch can escape digestion in the human small intestine and consequently enters the large intestine, where it may serve as a carbon source for bacterial fermentation. Thirty-eight types of human colonic bacteria were screened for their capacity to utilize soluble starch, gelatinized amylopectin maize starch, and high-amylose maize starch granules by measuring the clear zones on starch agar plates. The six cultures which produced clear zones on amylopectin maize starch- containing plates were selected for further studies for utilization of amylopectin maize starch and high-amylose maize starch granules A (amylose; Sigma) and B (Culture Pro 958N). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to detect bacterial starch-degrading enzymes. It was demonstrated that Bifidobacterium spp., Bacteroides spp., Fusobacterium spp., and strains of Eubacterium, Clostridium, Streptococcus, and Propionibacterium could hydrolyze the gelatinized amylopectin maize starch, while only Bifidobacterium spp. and Clostridium butyricum could efficiently utilize high-amylose maize starch granules. In fact, C. butyricum and Bifidobacterium spp. had higher specific growth rates in the autoclaved medium containing high-amylose maize starch granules and hydrolyzed 80 and 40% of the amylose, respectively. Starch-degrading enzymes were cell bound on Bifidobacterium and Bacteroides cells and were extracellular for C. butyricum. Active staining for starch-degrading enzymes on SDS-PAGE gels showed that the Bifidobacterium cells produced several starch-degrading enzymes with high relative molecular (M(r)) weights (>160,000), medium-sized relative molecular weights (>66,000), and low relative molecular weights (spp. and C. butyricum degraded and utilized granules of amylomaize starch.

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.

Some characteristics of a raw starch digestion inhibitory factor from Aspergillus niger

Energy Technology Data Exchange (ETDEWEB)

Towprayoon, S.; Saha, B.C.; Fujio, Yusaku; Ueda, Seinosuke

1988-09-01

The effect of an inhibitory factor (IF) from Aspergillus niger 19 on raw starch digestion by pure glucoamylase I of black Aspergillus, pure glucoamylase of Rhizopus niveus, bacterial ..cap alpha..-amylase, fungal ..cap alpha..-amylase and various combination was investigated. The IF caused higher inhibition of raw starch hydrolysis by the combined action of glucoamylase and fungal ..cap alpha..-amylase than of hydrolysis by the individual enzymes. A protein moiety of IF might play an active part in this inhibition phenomenon. The IF was found to starch granules, preventing hydrolysis by the enzymes, and caused decreased raw starch hydrolysis yields.

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.

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

OpenAIRE

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

1990-01-01

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

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...

Kinetic modeling of simultaneous saccharification and fermentation of corn starch for ethanol production.

Science.gov (United States)

Białas, Wojciech; Czerniak, Adrian; Szymanowska-Powałowska, Daria

2014-01-01

Fuel ethanol production, using a simultaneous saccharification and fermentation process (SSF) of native starch from corn flour, has been performed using Saccharomyces cerevisiae and a granular starch hydrolyzing enzyme. The quantitative effects of mash concentration, enzyme dose and pH were investigated with the use of a Box-Wilson central composite design protocol. Proceeding from results obtained in optimal fermentation conditions, a kinetics model relating the utilization rates of starch and glucose as well as the production rates of ethanol and biomass was tested. Moreover, scanning electron microscopy (SEM) was applied to investigate corn starch granule surface after the SFF process. A maximum ethanol concentration of 110.36 g/l was obtained for native corn starch using a mash concentration of 25%, which resulted in ethanol yield of 85.71%. The optimal conditions for the above yield were found with an enzyme dose of 2.05 ml/kg and pH of 5.0. These results indicate that by using a central composite design, it is possible to determine optimal values of the fermentation parameters for maximum ethanol production. The investigated kinetics model can be used to describe SSF process conducted with granular starch hydrolyzing enzymes. The SEM micrographs reveal randomly distributed holes on the surface of granules.

Effect of gelatinization and hydrolysis conditions on the selectivity of starch hydrolysis with alpha-amylase from Bacillus licheniformis.

Science.gov (United States)

Baks, Tim; Bruins, Marieke E; Matser, Ariette M; Janssen, Anja E M; Boom, Remko M

2008-01-23

Enzymatic hydrolysis of starch can be used to obtain various valuable hydrolyzates with different compositions. The effects of starch pretreatment, enzyme addition point, and hydrolysis conditions on the hydrolyzate composition and reaction rate during wheat starch hydrolysis with alpha-amylase from Bacillus licheniformis were compared. Suspensions of native starch or starch gelatinized at different conditions either with or without enzyme were hydrolyzed. During hydrolysis, the oligosaccharide concentration, the dextrose equivalent, and the enzyme activity were determined. We found that the hydrolyzate composition was affected by the type of starch pretreatment and the enzyme addition point but that it was just minimally affected by the pressure applied during hydrolysis, as long as gelatinization was complete. The differences between hydrolysis of thermally gelatinized, high-pressure gelatinized, and native starch were explained by considering the granule structure and the specific surface area of the granules. These results show that the hydrolyzate composition can be influenced by choosing different process sequences and conditions.

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

Science.gov (United States)

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

2018-02-15

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

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.

Sugar-mediated semidian oscillation of gene expression in the cassava storage root regulates starch synthesis

Energy Technology Data Exchange (ETDEWEB)

Jansson, Christer; Baguma, Yona; Sun, Chuanxin; Boren, Mats; Olsson, Helena; Rosenqvist, Sara; Mutisya, Joel; Rubaihayo, Patrick R.; Jansson, Christer

2008-01-15

Starch branching enzyme (SBE) activity in the cassava storage root exhibited a diurnal fluctuation, dictated by a transcriptional oscillation of the corresponding SBE genes. The peak of SBE activity coincided with the onset of sucrose accumulation in the storage, and we conclude that the oscillatory mechanism keeps the starch synthetic apparatus in the storage root sink in tune with the flux of sucrose from the photosynthetic source. When storage roots were uncoupled from the source, SBE expression could be effectively induced by exogenous sucrose. Turanose, a sucrose isomer that cannot be metabolized by plants, mimicked the effect of sucrose, demonstrating that downstream metabolism of sucrose was not necessary for signal transmission. Also glucose and glucose-1-P induced SBE expression. Interestingly, induction by sucrose, turanose and glucose but not glucose-1-P sustained an overt semidian (12-h) oscillation in SBE expression and was sensitive to the hexokinase (HXK) inhibitor glucosamine. These results suggest a pivotal regulatory role for HXK during starch synthesis. Abscisic acid (ABA) was another potent inducer of SBE expression. Induction by ABA was similar to that of glucose-1-P in that it bypassed the semidian oscillator. Both the sugar and ABA signaling cascades were disrupted by okadaic acid, a protein phosphatase inhibitor. Based on these findings, we propose a model for sugar signaling in regulation of starch synthesis in the cassava storage root.

Milling of rice grains. The degradation on three structural levels of starch in rice flour can be independently controlled during grinding.

Science.gov (United States)

Tran, Thuy T B; Shelat, Kinnari J; Tang, Daniel; Li, Enpeng; Gilbert, Robert G; Hasjim, Jovin

2011-04-27

Whole polished rice grains were ground using cryogenic and hammer milling to understand the mechanisms of degradation of starch granule structure, whole (branched) molecular structure, and individual branches of the molecules during particle size reduction (grinding). Hammer milling caused greater degradation to starch granules than cryogenic milling when the grains were ground to a similar volume-median diameter. Molecular degradation of starch was not evident in the cryogenically milled flours, but it was observed in the hammer-milled flours with preferential cleavage of longer (amylose) branches. This can be attributed to the increased grain brittleness and fracturability at cryogenic temperatures, reducing the mechanical energy required to diminish the grain size and thus reducing the probability of chain scission. The results indicate, for the first time, that branching, whole molecule, and granule structures of starch can be independently altered by varying grinding conditions, such as grinding force and temperature.

Effects of protease and non-starch polysaccharide enzyme on performance, digestive function, activity and gene expression of endogenous enzyme of broilers.

Directory of Open Access Journals (Sweden)

Lin Yuan

Full Text Available Three hundred one-day-old male broiler chickens (Ross-308 were fed corn-soybean basal diets containing non-starch polysaccharide (NSP enzyme and different levels of acid protease from 1 to 42 days of age to investigate the effects of exogenous enzymes on growth performance, digestive function, activity of endogenous digestive enzymes in the pancreas and mRNA expression of pancreatic digestive enzymes. For days 1-42, compared to the control chickens, average daily feed intake (ADFI and average daily gain (ADG were significantly enhanced by the addition of NSP enzyme in combination with protease supplementation at 40 or 80 mg/kg (p<0.05. Feed-to-gain ratio (FGR was significantly improved by supplementation with NSP enzymes or NSP enzyme combined with 40 or 80 mg/kg protease compared to the control diet (p<0.05. Apparent digestibility of crude protein (ADCP was significantly enhanced by the addition of NSP enzyme or NSP enzyme combined with 40 or 80 mg/kg protease (p<0.05. Cholecystokinin (CCK level in serum was reduced by 31.39% with NSP enzyme combined with protease supplementation at 160 mg/kg (p<0.05, but the CCK level in serum was increased by 26.51% with NSP enzyme supplementation alone. After 21 days, supplementation with NSP enzyme and NSP enzyme combined with 40 or 80 mg/kg protease increased the activity of pancreatic trypsin by 74.13%, 70.66% and 42.59% (p<0.05, respectively. After 42 days, supplementation with NSP enzyme and NSP enzyme combined with 40 mg/kg protease increased the activity of pancreatic trypsin by 32.45% and 27.41%, respectively (p<0.05. However, supplementation with NSP enzyme and 80 or 160 mg/kg protease decreased the activity of pancreatic trypsin by 10.75% and 25.88%, respectively (p<0.05. The activities of pancreatic lipase and amylase were significantly higher in treated animals than they were in the control group (p<0.05. Supplementation with NSP enzyme, NSP enzyme combined with 40 or 80 mg/kg protease increased

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.

Silver nanoparticles: a potential nanocatalyst for the rapid degradation of starch hydrolysis by α-amylase.

Science.gov (United States)

Ernest, Vinita; Shiny, P J; Mukherjee, Amitava; Chandrasekaran, N

2012-05-01

Silver nanoparticles (AgNPs) are proven to be an effective catalytic material for various applications due to their excellent optical and electronic properties. In this paper, we describe a novel approach for the degradation of starch using the catalytic behaviour of AgNPs in an enzyme catalysed reaction of starch hydrolysis by α-amylase. AgNPs were synthesized by soluble starch reducing silver nitrate to silver atoms. An increase of 4.7-fold in reducing sugar formation and 1.5 times faster enzyme activity confirmed the catalytic activity of AgNPs as a nanocatalyst. Surprisingly, starch degradation tests revealed that 9.9 mg of starch was hydrolysed within 5 min, which corroborates with the reducing sugar assay. In short, the present study paves way for the faster degradation of starch by immobilizing the enzyme onto the surface of the AgNP, which could be a promising application in the food industry. Copyright © 2012 Elsevier Ltd. All rights reserved.

EFFECT OF ENDOSPERM HARDNESS ON AN ETHANOL PROCESS USING A GRANULAR STARCH HYDROLYZING ENZYME

Energy Technology Data Exchange (ETDEWEB)

Wang, P; W Liu, D B; Johnston, K D; Rausch, S J; Schmidt, M E; Tumbleson, V Singh

2010-01-01

Granular starch hydrolyzing enzymes (GSHE) can hydrolyze starch at low temperature (32°C). The dry grind process using GSHE (GSH process) has fewer unit operations and no changes in process conditions (pH 4.0 and 32°C) compared to the conventional process because it dispenses with the cooking and liquefaction step. In this study, the effects of endosperm hardness, protease, urea, and GSHE levels on GSH process were evaluated. Ground corn, soft endosperm, and hard endosperm were processed using two GSHE levels (0.1 and 0.4 mL per 100 g ground material) and four treatments of protease and urea addition. Soft and hard endosperm materials were obtained by grinding and sifting flaking grits from a dry milling pilot plant; classifications were confirmed using scanning electron microscopy. During 72 h of simultaneous granular starch hydrolysis and fermentation (GSHF), ethanol and glucose profiles were determined using HPLC. Soft endosperm resulted in higher final ethanol concentrations compared to ground corn or hard endosperm. Addition of urea increased final ethanol concentrations for soft and hard endosperm. Protease addition increased ethanol concentrations and fermentation rates for soft endosperm, hard endosperm, and ground corn. The effect of protease addition on ethanol concentrations and fermentation rates was most predominant for soft endosperm, less for hard endosperm, and least for ground corn. Samples (soft endosperm, hard endosperm, or corn) with protease resulted in higher (1.0% to 10.5% v/v) ethanol concentration compared to samples with urea. The GSH process with protease requires little or no urea addition. For fermentation of soft endosperm, GSHE dose can be reduced. Due to nutrients (lipids, minerals, and soluble proteins) present in corn that enhance yeast growth, ground corn fermented faster at the beginning than hard and soft endosperm.

Immobilization of α-amylase and amyloglucosidase onto ion-exchange resin beads and hydrolysis of natural starch at high concentration.

Science.gov (United States)

Gupta, Kapish; Jana, Asim Kumar; Kumar, Sandeep; Maiti, Mithu

2013-11-01

α-Amylase was immobilized on Dowex MAC-3 with 88 % yield and amyloglucosidase on Amberlite IRA-400 ion-exchange resin beads with 54 % yield by adsorption process. Immobilized enzymes were characterized to measure the kinetic parameters and optimal operational parameters. Optimum substrate concentration and temperature were higher for immobilized enzymes. The thermal stability of the enzymes enhanced after the immobilization. Immobilized enzymes were used in the hydrolysis of the natural starch at high concentration (35 % w/v). The time required for liquefaction of starch to 10 dextrose equivalent (DE) and saccharification of liquefied starch to 96 DE increased. Immobilized enzymes showed the potential for use in starch hydrolysis as done in industry.

Selectivity of the surface binding site (SBS) on barley starch synthase I

DEFF Research Database (Denmark)

Wilkens, Casper; Cuesta-Seijo, Jose A.; Palcic, Monica

2014-01-01

Starch synthase I (SSI) from various sources has been shown to preferentially elongate branch chains of degree of polymerisation (DP) from 6–7 to produce chains of DP 8–12. In the recently determined crystal structure of barley starch synthase I (HvSSI) a so-called surface binding site (SBS) was ...

In vitro biochemical characterization of all barley endosperm starch synthases

DEFF Research Database (Denmark)

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

2016-01-01

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

Glycogen branching enzyme (GBE1) mutation causing equine glycogen storage disease IV.

Science.gov (United States)

Ward, Tara L; Valberg, Stephanie J; Adelson, David L; Abbey, Colette A; Binns, Matthew M; Mickelson, James R

2004-07-01

Comparative biochemical and histopathological evidence suggests that a deficiency in the glycogen branching enzyme, encoded by the GBE1 gene, is responsible for a recently identified recessive fatal fetal and neonatal glycogen storage disease (GSD) in American Quarter Horses termed GSD IV. We have now derived the complete GBE1 cDNA sequences for control horses and affected foals, and identified a C to A substitution at base 102 that results in a tyrosine (Y) to stop (X) mutation in codon 34 of exon 1. All 11 affected foals were homozygous for the X34 allele, their 11 available dams and sires were heterozygous, and all 16 control horses were homozygous for the Y34 allele. The previous findings of poorly branched glycogen, abnormal polysaccharide accumulation, lack of measurable GBE1 enzyme activity and immunodetectable GBE1 protein, coupled with the present observation of abundant GBE1 mRNA in affected foals, are all consistent with the nonsense mutation in the 699 amino acid GBE1 protein. The affected foal pedigrees have a common ancestor and contain prolific stallions that are likely carriers of the recessive X34 allele. Defining the molecular basis of equine GSD IV will allow for accurate DNA testing and the ability to prevent occurrence of this devastating disease affecting American Quarter Horses and related breeds.

Enhanced starch hydrolysis using α-amylase immobilized on cellulose ultrafiltration affinity membrane.

Science.gov (United States)

Konovalova, Viktoriia; Guzikevich, Kateryna; Burban, Anatoliy; Kujawski, Wojciech; Jarzynka, Karolina; Kujawa, Joanna

2016-11-05

In order to prepare ultrafiltration membranes possessing biocatalytic properties, α-amylase has been immobilized on cellulose membranes. Enzyme immobilization was based on a covalent bonding between chitosan and a surface of cellulose membrane, followed by an attachment of Cibacron Blue F3G-A dye as affinity ligand. Various factors affecting the immobilization process, such as enzyme concentration, pH of modifying solution, zeta-potential of membrane surface, and stability of immobilized enzyme were studied. The applicability of immobilized α-amylase has been investigated in ultrafiltration processes. The immobilization of α-amylase on membrane surface allows to increase the value of mass transfer coefficient and to decrease the concentration polarization effect during ultrafiltration of starch solutions. The enzyme layer on the membrane surface prevents a rapid increase of starch concentration due to the amylase hydrolysis of starch in the boundary layer. The presented affinity immobilization technique allows also for the regeneration of membranes from inactivated enzyme. Copyright © 2016 Elsevier Ltd. All rights reserved.

Elucidation of substituted ester group position in octenylsuccinic anhydride modified sugary maize soluble starch.

Science.gov (United States)

Ye, Fan; Miao, Ming; Huang, Chao; Lu, Keyu; Jiang, Bo; Zhang, Tao

2014-12-03

The octenylsuccinic groups in esterification-modified sugary maize soluble starches with a low (0.0191) or high (0.0504) degree of substitution (DS) were investigated by amyloglucosidase hydrolysis followed by a combination of chemical and physical analysis. The results showed the zeta-potential remained at approximately the same value regardless of excessive hydrolysis. The weight-average molecular weight decreased rapidly and reached 1.22 × 10(7) and 1.60 × 10(7) g/mol after 120 min for low-DS and high-DS octenylsuccinic anhydride (OSA) modified starch, respectively. The pattern of z-average radius of gyration as well as particle size change was similar to that of Mw, and z-average radius of gyration decreased much more slowly, especially for high-DS OSA starch. Compared to native starch, two characteristic absorption peaks at 1726.76 and 1571.83 cm(-1) were observed in FT-IR spectra, and the intensity of absorption peaks increased with increasing DS. The NMR results showed that OSA starch had several additional peaks at 0.8-3.0 ppm and a shoulder at 5.56 ppm for OSA substituents, which were grafted at O-2 and O-3 positions in soluble starch. The even distribution of OSA groups in the center area of soluble starch particle has been directly shown under CLSM. Most substitutions were located near branching points of soluble starch particles for a low-DS modified starch, whereas the substituted ester groups were located near branching points as well as at the nonreducing ends in OSA starch with a high DS.

Effect of dietary starch source on milk production and composition of ...

African Journals Online (AJOL)

huis

The larger granules of more enzyme-resistant B-type crystalline starch in ... of nonstructural carbohydrates increases the utilization of ruminal ammonia-N ..... An improved enzymatic method for the determination of native and modified starch. J.

Optimization of maltodextrin production from avocado seed starch by response surface methodology

Science.gov (United States)

Nguyen, Thanh Viet; Ma, Tuyen-Hoang Nguyen; Nguyen, Tha Thi; Ho, Vinh-Nghi Kim; Vo, Hau Tan

2018-04-01

A process for maltodextrin production from avocado seed starch was reported in this study. Response surface methodology was used to investigate the effects of three independent variables for hydrolysis of the starch using a commercial food-grade α-amylase, Termamyl SC. These variables included enzyme concentration (0.05 - 0.15% starch), pH (5.0 - 6.0) and hydrolysis time (1.0 - 3.0 h), while the temperature fixed at 95°C. The result showed that the optimum conditions were using enzyme concentration at 0.12%, pH at 5.5 and 2.75 h of the incubation time. Under the optimum conditions, the recovered starch yield was 79.8% and the maltodextrin powder had 15.8 of dextrose equivalent.

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

Glucan, Water Dikinase Activity Stimulates Breakdown of Starch Granules by Plastidial β-Amylases1[W][OA

Science.gov (United States)

Edner, Christoph; Li, Jing; Albrecht, Tanja; Mahlow, Sebastian; Hejazi, Mahdi; Hussain, Hasnain; Kaplan, Fatma; Guy, Charles; Smith, Steven M.; Steup, Martin; Ritte, Gerhard

2007-01-01

Glucan phosphorylating enzymes are required for normal mobilization of starch in leaves of Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum), but mechanisms underlying this dependency are unknown. Using two different activity assays, we aimed to identify starch degrading enzymes from Arabidopsis, whose activity is affected by glucan phosphorylation. Breakdown of granular starch by a protein fraction purified from leaf extracts increased approximately 2-fold if the granules were simultaneously phosphorylated by recombinant potato glucan, water dikinase (GWD). Using matrix-assisted laser-desorption ionization mass spectrometry several putative starch-related enzymes were identified in this fraction, among them β-AMYLASE1 (BAM1; At3g23920) and ISOAMYLASE3 (ISA3; At4g09020). Experiments using purified recombinant enzymes showed that BAM1 activity with granules similarly increased under conditions of simultaneous starch phosphorylation. Purified recombinant potato ISA3 (StISA3) did not attack the granular starch significantly with or without glucan phosphorylation. However, starch breakdown by a mixture of BAM1 and StISA3 was 2 times higher than that by BAM1 alone and was further enhanced in the presence of GWD and ATP. Similar to BAM1, maltose release from granular starch by purified recombinant BAM3 (At4g17090), another plastid-localized β-amylase isoform, increased 2- to 3-fold if the granules were simultaneously phosphorylated by GWD. BAM activity in turn strongly stimulated the GWD-catalyzed phosphorylation. The interdependence between the activities of GWD and BAMs offers an explanation for the severe starch excess phenotype of GWD-deficient mutants. PMID:17631522

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

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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.

Effects of alpha-amylase reaction mechanisms on analysis of resistant-starch contents.

Science.gov (United States)

Moore, Samuel A; Ai, Yongfeng; Chang, Fengdan; Jane, Jay-lin

2015-01-22

This study aimed to understand differences in the resistant starch (RS) contents of native and modified starches obtained using two standard methods of RS content analysis: AOAC Method 991.43 and 2002.02. The largest differences were observed in native potato starch, cross-linked wheat distarch phosphate, and high-amylose corn starch stearic-acid complex (RS5) between using AOAC Method 991.43 with Bacillus licheniformis α-amylase (BL) and AOAC Method 2002.02 with porcine pancreatic α-amylase (PPA). To determine possible reasons for these differences, we hydrolyzed raw-starch granules with BL and PPA with equal activity at pH 6.9 and 37°C for up to 84 h and observed the starch granules displayed distinct morphological differences after the hydrolysis. Starches hydrolyzed by BL showed erosion on the surface of the granules; those hydrolyzed by PPA showed pitting on granule surfaces. These results suggested that enzyme reaction mechanisms, including the sizes of the binding sites and the reaction patterns of the two enzymes, contributed to the differences in the RS contents obtained using different methods of RS analysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Intactness of cell wall structure controls the in vitro digestion of starch in legumes.

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Dhital, Sushil; Bhattarai, Rewati R; Gorham, John; Gidley, Michael J

2016-03-01

Increasing the level of starch that is not digested by the end of the small intestine and therefore enters the colon ('resistant starch') is a major opportunity for improving the nutritional profile of foods. One mechanism that has been shown to be successful is entrapment of starch within an intact plant tissue structure. However, the level of tissue intactness required for resistance to amylase digestion has not been defined. In this study, intact cells were isolated from a range of legumes after thermal treatment at 60 °C (starch not gelatinised) or 95 °C (starch gelatinised) followed by hydrolysis using pancreatic alpha amylase. It was found that intact cells, isolated at either temperature, were impervious to amylase. However, application of mechanical force damaged the cell wall and made starch accessible to digestive enzymes. This shows that the access of enzymes to the entrapped swollen starch is the rate limiting step controlling hydrolysis of starch in cooked legumes. The results suggest that a single cell wall could be sufficient to provide an effective delivery of starch to the large intestine with consequent nutritional benefits, provided that mechanical damage during digestion is avoided.

Starch and alpha-glucan acting enzymes, modulating their properties by directed evolution

NARCIS (Netherlands)

Kelly, Ronan M.; Dijkhuizen, Lubbert; Leemhuis, Hans

2009-01-01

Starch is the major food reserve in plants and forms a large part of the daily calorie intake in the human diet. Industrially, starch has become a major raw material in the production of various products including bio-ethanol, coating and anti-stating agents. The complexity and diversity of these

Engineering Potato Starch with a Higher Phosphate Content.

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Xuan Xu

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

Enzymatic Modification of Corn Starch Influences Human Fecal Fermentation Profiles.

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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.

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....

The effect of dietary faba bean and non-starch polysaccharide degrading enzymes on the growth performance and gut physiology of young turkeys.

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Mikulski, D; Juskiewicz, J; Przybylska-Gornowicz, B; Sosnowska, E; Slominski, B A; Jankowski, J; Zdunczyk, Z

2017-12-01

The aim of this study was to investigate the effect of dietary replacement of soya bean meal (SBM) with faba bean (FB) and a blend of non-starch polysaccharide (NSP) degrading enzymes on the gastrointestinal function, growth performance and welfare of young turkeys (1 to 56 days of age). An experiment with a 2×2 factorial design was performed to compare the efficacy of four diets: a SBM-based diet and a diet containing FB, with and without enzyme supplementation (C, FB, CE and FBE, respectively). In comparison with groups C, higher dry matter content and lower viscosity of the small intestinal digesta were noted in groups FB. The content of short-chain fatty acids (SCFAs) in the small intestinal digesta was higher in groups FB, but SCFA concentrations in the caecal digesta were comparable in groups C and FB. In comparison with control groups, similar BW gains, higher feed conversion ratio (FCR), higher dry matter content of excreta and milder symptoms of footpad dermatitis (FPD) were noted in groups FB. Enzyme supplementation increased the concentrations of acetate, butyrate and total SCFAs, but it did not increase the SCFA pool in the caecal digesta. The enzymatic preparation significantly improved FCR, reduced excreta hydration and the severity of FPD in turkeys. It can be concluded that in comparison with the SBM-based diet, the diet containing 30% of FB enables to achieve comparable BW gains accompanied by lower feed efficiency during the first 8 weeks of rearing. Non-starch polysaccharide-degrading enzymes can be used to improve the nutritional value of diets for young turkeys, but more desirable results of enzyme supplementation were noted in the SBM-based diet than in the FB-based diet.

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

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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

ENZYMATIC DETERMINATION OF STARCH IN DOCE DE LEITE USING DIALYSIS

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DEMIATE Ivo Motim

2001-01-01

Full Text Available The importance of starch for the food industry makes it necessary to develop new, fast, economic and accurate methodologies for its quantification. In the present paper starch hydrolysis using commercial enzymes of industrial grade are studied aiming to develop an easy and cheap analysis, available to a greater number of industries and technicians. The proposed method is simple, divided in a first step where soluble sugars are eliminated from the samples by using dialysis, followed by starch hydrolysis of the retained fraction with a thermoresistent bacterial alfa-amylase (Termamyl 120L® and an amyloglucosidase (AMG 300L®. The hydrolysis conditions were those suggested by the enzyme producer. After the hydrolysis step the material was dialysed again for the extraction of glucose that was quantified by the glucose-oxidase colorimetric reactant. The results allowed the construction of calibration equations for starch determination on the analyzed samples. These samples were produced on a laboratory scale and native and acid-modified corn starches were added in known concentrations. By considering the final dilutions employed for glucose determination on the samples, it was possible to confirm that they were identical to that of the glucose-oxidase reactant calibration.

A titration approach to identify the capacity for starch digeston in milk-fed calves

NARCIS (Netherlands)

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

2015-01-01

Calf milk replacers (MR) commonly contain 40% to 50% lactose. For economic reasons, starch is of interest as a lactose replacer. Compared with lactose, starch digestion is generally low in calves. It is, however, unknown which enzyme limits the rate of starch digestion. The objectives were to

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

NARCIS (Netherlands)

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

Calf milk replacers (MR) commonly contain 40% to 50% lactose. For economic reasons, starch is of interest as a lactose replacer. Compared with lactose, starch digestion is generally low in calves. It is, however, unknown which enzyme limits the rate of starch digestion. The objectives were to

Two-stage in vitro digestibility assay, a tool for formulating non-starch polysaccharide degrading enzyme combinations for commonly used feed ingredients of poultry rations

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Y. Ramana Reddy

2013-05-01

Full Text Available Aim: An attempt was made to assess the effect of pure enzyme combinations with the objective of formulating customized enzyme mixtures based on sugar release when subjected to two-stage in vitro digestion assay. Materials and Methods: A two-stage in vitro digestibility assay was carried out for commonly used feed ingredients for poultry viz., maize, soy bean meal, sunflower cake, and de-oiled rice bran supplemented with three concentrations of xylanase (5000; 7500 and 10000 IU/kg, cellulase (50; 100 and 400 IU/kg and â-D-glucanase (100; 200 and 400 IU/kg were used to formulate various NSP enzymes combinations. In total 27 NSP enzyme combinations (3x3x3 were formulated and the sugar released due to NSP digestion was quantified by phenol sulphuric acid method. Results: The total sugar release was significantly (P<0.05 higher with supplementation of various enzymes combinations for maize, sunflower cake and de-oiled rice bran where as no significant (P<0.05 interaction of various NSP enzymes combinations was observed for soy bean meal. The NSP digestibility was highest in combination (xylanase-5000, cellulase-50 and â-D-glucanase-400 IU/kg, (xylanase-10000, cellulase-50 and â-D-glucanase-200 IU/kg and (xylanase-7500, cellulase- 100 and â-D-glucanase-100 IU/kg for maize, sunflower cake and de-oiled rice bran respectively. In case of sunflower cake, significant (P<0.01 three way interaction was observed among the xylanase, cellulose, and â-D-glucanase enzymes and the two-way interactions between the enzymes were also significant (P<0.01. Conclusion: It is concluded that 'n' number of non-starch Polysaccharide enzymes combinations can be screened for their efficiency to digest non-starch Polysaccharides present in various feed ingredients commonly used in poultry rations by employing two-stage in vitro digestibility assay as a tool. [Vet World 2013; 6(8.000: 525-529

Maltase-glucoamylase modulates gluconeogenesis and sucrase-isomaltase dominates starch digestion glucogenesis

Science.gov (United States)

Six enzyme activities are needed to digest starch to absorbable free glucose; 2 luminal alpha-amylases (AMY) and 4 mucosal maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI) subunit activities are involved in the digestion. The AMY activities break down starch to soluble oligomeric dextrins; mu...

Influence of non starch polysaccharide-degrading enzymes on the ...

African Journals Online (AJOL)

STORAGESEVER

2010-03-08

Mar 8, 2010 ... A total of 195 1-d-old male broiler chicks (Ross 308) were allocated to 5 treatment groups ... by reducing the anti-nutritional effects of non-starch polysaccharides ..... mineral density and weights of the head, neck and back.

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

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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.

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.

Direct evidence for the inactivation of branched-chain oxo-acid dehydrogenase by enzyme phosphorylation

International Nuclear Information System (INIS)

Odessey, R.

1980-01-01

The branched-chain 2-oxo-acid dehydrogenase (BCOAD) from mitochondria of several different rat tissues is inactivated by ATP and can be reactivated by incubation in Mg 2+ -containing buffers. Work carried out on the system from skeletal muscle mitochondria has shown that inactivation requires the cleavage of the γ-phosphate group of ATP and that modification is covalent. The non-metabolized ATP analog, p[NH]ppA, can block the inhibitory effect of ATP when added prior to ATP addition, but cannot reverse the inhibition of the inactivated dehydrogenase. These and other data raise the possibility that BCOAD may be regulated by enzyme phosphorylation. This hypothesis is supported by the finding that various procedures which separate the enzyme from its mitochondrial environment (e.g. detergent treatment, ammonium sulfate precipitation and freeze-thawing) do not alter the degree of inhibition induced by ATP in the mitochondrial preincubation. These experiments suggested the feasibility of labelling the enzyme with 32 P and purifying it. (Auth.)

Purification and properties of amylolytic enzyme from Aspergillus oryzae MIBA316

OpenAIRE

仮屋, 麻紀子; 矢野, めぐむ; 瀧井, 幸男; Makiko, Kariya; Megumu, Yano; Yukio, Takii

2003-01-01

Amylolytic enzyme was purified to electrophoretically homogeneous state from culture broth of Aspergillus oryzae MIBA316. This enzyme hydrolyzed preferentially amylopectin, starch and glycogen. Approaches to complete breakdown of starch to its components and their utilization in food processing were discussed.

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

Science.gov (United States)

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

2015-09-20

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

[Enhancement of photoassimilate utilization by manipulation of the ADPglucose pyrophosphorylase gene]. Progress report, [March 15, 1989--April 14, 1990

Energy Technology Data Exchange (ETDEWEB)

Okita, T.W.

1990-12-31

The long term aim of this project is to assess the feasibility of increasing the conversion of photosynthate into starch via manipulation of the gene that encodes for ADPglucose pyrophosphorylase, a key regulatory enzyme of starch biosynthesis. In developing storage tissues such as cereal seeds and tubers, starch biosynthesis is regulated by the gene activation and expression of ADPglucose pyrophosphorylase, starch synthase, branching enzyme and other ancillary starch modifying enzymes, as well as the allosteric-controlled behavior of ADPglucose pyrophosphorylase activity. During the last two years we have obtained information on the structure of this enzyme from both potato tuber and rice endosperm, using a combination of biochemical and molecular biological approaches. Moreover, we present evidence that this enzyme may be localized at discrete regions of the starch grain within the amyloplast, and plays a role in controlling overall starch biosynthesis in potato tubers.

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

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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

distribution, abundance and properties of restriction enzymes

African Journals Online (AJOL)

DNA of granule-bound starch synthase (GBSS) I and II with a view to ... properties for manipulation of the genes for production of modified starch. .... procurement, storage and handling of the ..... been made on restriction enzymes of potato,.

Effect of Enzyme Preparation with Activity Directed Towards Degradation of Non Starch Polysaccharides on Yellow Lupine Seed Based Diet for Young Broilers

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Bogusław I Olkowski

2010-01-01

Full Text Available This work examined the impact of enzyme preparation with specific activity towards non starch polysaccharides on performance, morphological characteristics of gastrointestinal tract organs, microscopic evaluation of jejunal mucosa, and microbial status of ileum, caeca, and excreta in broilers fed a diet containing a high content of lupine meal. One-day-old chickens (Ross 308, mixed sex were randomly divided into control and experimental groups. Each group consisted of 36 birds, with 6 replications,and with 6 chickens per replication. The control group was fed the basal diet (consisting of maize and 40% of lupine, while the experimental treatment group was fed the basal diet supplemented with 0.06% commercial enzyme (Ronozyme VP. Chickens were fed diets in mash form for 4 weeks. Enzyme preparation significantly (P P P Enterobacteriaceae in caeca and excreta, and coliforms in excreta only (P < 0.01. Appropriate combination of enzyme preparations with activity towards degrading carbohydrates may offer a potential to reduce the deleterious impact of lupine in broilers.

Development of modified starch technology (maltodextrin) from commercial tapioca on semi production scale using oil heater dextrinator

Science.gov (United States)

Triyono, Agus; Cecep Erwan Andriansyah, Raden; Luthfiyanti, Rohmah; Rahman, Taufik

2017-12-01

One way to improve functional starch is by modification of starch into dextrin or maltodextrin. Maltodextrin is used in the food industry as a food substitution. Development of enzymatically modified starch technology has been performed with the use of α-amylase at optimum pH of 5.5, temperature 75-85 °C, with enzyme activity of 135 KNU/g. The maltodextrin produced from commercial tapioca has the quality requirements for food according to SNI 1992. The yield of maltodextrin obtained is about 80%. The use of the optimum amount of the α-amylase enzyme is 0.07 % v/w and the substrate amount of tapioca starch is 35%. Analysis of the feasibility of modified starch with the assumption of production scale of 300 kg per day, the economic value of 10 years business, the price of starch is IDR 8,350/kg, from tapioca starch (tapioca) IDR 4,000 - IDR 4,500/kg.

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.

Encapsulating fatty acid esters of bioactive compounds in starch

Science.gov (United States)

Lay Ma, Ursula Vanesa

Interest in the use of many bioactive compounds in foods is growing in large part because of the apparent health benefits of these molecules. However, many of these compounds can be easily degraded during processing, storage, or their passage through the gastrointestinal tract before reaching the target site. In addition, they can be bitter, acrid, or astringent, which may negatively affect the sensory properties of the product. Encapsulation of these molecules may increase their stability during processing, storage, and in the gastrointestinal tract, while providing controlled release properties. The ability of amylose to form inclusion complexes and spherulites while entrapping certain compounds has been suggested as a potential method for encapsulation of certain molecules. However, complex formation and spherulitic crystallization are greatly affected by the type of inclusion molecules, type of starch, and processing conditions. The objectives of the present investigation were to: (a) study the effect of amylose, amylopectin, and intermediate material on spherulite formation and its microstructure; (b) investigate the formation of amylose and high amylose starch inclusion complexes with ascorbyl palmitate, retinyl palmitate, and phytosterol esters; (c) evaluate the ability of spherulites to form in the presence of fatty acid esters and to entrap ascorbyl palmitate, retinyl palmitate, and phytosterol esters; and (d) evaluate the effect of processing conditions on spherulite formation and fatty acid ester entrapment. Higher ratios of linear to branched molecules resulted in the formation of more and rounder spherulites with higher heat stability. In addition to the presence of branches, it appears that spherulitic crystallization is also affected by other factors, such as degree of branching, chain length, and chain length distribution. Amylose and Hylon VII starch formed inclusion complexes with fatty acid esters of ascorbic acid, retinol, or phytosterols

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

Science.gov (United States)

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

2009-08-12

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

Fermentation of starch by Klebsiella oxytoca P2, containing plasmids with {alpha}-amylase and pullulanase genes

Energy Technology Data Exchange (ETDEWEB)

Santos, V.L. dos; Araujo, E.F.; Barros, E.G. de; Guimaraes, W.V.

1999-12-20

Klebsiella oxytoca P2(pC46), an ethanol-producing recombinant, has been evaluated in fermentation of maltose and starch. The maximum ethanol produced by P2(pC46) was 0.34 g ethanol/g maltose and 0.38, 0.40, or 0.36 g ethanol/g starch in fermentation of 1, 2, or 4% starch, representing 68, 71, and 64% the theoretical yield. The pC46 plasmid transformed to cells of K. oxytoca P2 reduced the ethanol production from maltose and starch. In fermentation of starch after its digestion at 60 C for 24 h, in two-step fermentation, the time for maximum ethanol production was reduced to 12--24 h and the theoretical yield was around 90%. The increase in starch concentration resulted in lower {alpha}-amylase activity but in higher pullulanase activity. The high activity and thermostability of the amylolytic enzymes from this transformant suggest that it has a potential for amylolytic enzymes source.

Effect of DHA supplementation on digestible starch utilization by rainbow trout.

Science.gov (United States)

Tapia-Salazar, M; Bureau, W; Panserat, S; Corraze, G; Bureau, D P

2006-01-01

Rainbow trout has a limited ability to utilize digestible carbohydrates efficiently. Trout feeds generally contain high levels of DHA, a fatty acid known to inhibit a number of glycolytic and lipogenic enzymes in animals. A study was conducted to determine whether carbohydrate utilization by rainbow trout might be affected by dietary DHA level. Two low-carbohydrate (digestible carbohydrate) basal diets were formulated to contain 1 (adequate) or 4 (excess) g/100 g DHA diet respectively. The two basal diets were diluted with increasing levels of digestible starch (0 %, 10 %, 20 % and 30 %, respectively) to produce eight diets. These diets were fed to fish for 12 weeks at 15 degrees C according to a pair-fed protocol that consisted of feeding the same amount of basal diet but different amounts of starch. Live weight, N and lipid gains, hepatic glycogen and plasma glucose values significantly increased, whereas feed efficiency (gain:feed) significantly decreased, with increasing starch intake (Pdigestible N intake) improved with starch supplementation but was not affected by DHA level (P>0.05). Starch increased the activity of glucokinase, pyruvate kinase, glucose 6-phosphate dehydrogenase and fatty acid synthase (P<0.05) but did not affect hexokinase and malic enzyme activity. DHA had no effect on growth but increased plasma glucose and reduced carcass lipid and liver glycogen contents (P<0.05). Glycolytic and lipogenic enzymes were not affected by DHA level, except for pyruvate kinase, which was reduced by increasing DHA level. These results suggest only a marginal effect of dietary DHA on the ability of fish to utilize carbohydrate.

The deposition and characterization of starch in Brachypodium distachyon

DEFF Research Database (Denmark)

Tanackovic, Vanja; Svensson, Jan T.; Jensen, Susanne Langgård

2014-01-01

doughnut shaped and bimodally distributed into distinct small B-type (2.5-10 µm) and very small C-type (0.5-2.5 µm) granules. Large A-type granules, typical of cereals, were absent. Starch-bound phosphate, important for starch degradation, was 2-fold lower in Brachypodium compared with barley indicating...... different requirements for starch mobilization. The amylopectin branch profiles were similar and the amylose content was only slightly higher compared with barley cv. Golden Promise. The crystallinity of Brachypodium starch granules was low (10%) compared to barley (20%) as determined by wide-angle X......-ray scattering (WAXS) and molecular disorder was confirmed by differential scanning calorimetry (DSC). The expression profiles in grain for most genes were distinctly different for Brachypodium compared to barley, typically showing earlier decline during the course of development, which can explain the low...

Physical and functional properties of arrowroot starch extrudates.

Science.gov (United States)

Jyothi, A N; Sheriff, J T; Sajeev, M S

2009-03-01

Arrowroot starch, a commercially underexploited tuber starch but having potential digestive and medicinal properties, has been subjected to extrusion cooking using a single screw food extruder. Different levels of feed moisture (12%, 14%, and 16%) and extrusion temperatures (140, 150, 160, 170, 180, and 190 degrees C) were used for extrusion. The physical properties--bulk density, true density, porosity, and expansion ratio; functional properties such as water absorption index, water solubility index, oil absorption index, pasting, rheological, and textural properties; and in vitro enzyme digestibility of the extrudates were determined. The expansion ratio of the extrudates ranged from 3.22 to 6.09. The water absorption index (6.52 to 8.85 g gel/g dry sample), water solubility index (15.92% to 41.31%), and oil absorption index (0.50 to 1.70 g/g) were higher for the extrudates in comparison to native starch (1.81 g gel/g dry sample, 1.16% and 0.60 g/g, respectively). The rheological properties, storage modulus, and loss modulus of the gelatinized powdered extrudates were significantly lower (P extruded at higher feed moisture and lower extrusion temperature, whereas snap force and energy were higher at lower feed moisture and temperature. There was a significant decrease in the percentage digestibility of arrowroot starch (30.07% after 30 min of incubation with the enzyme) after extrusion (25.27% to 30.56%). Extrusion cooking of arrowroot starch resulted in products with very good expansion, color, and lower digestibility, which can be exploited for its potential use as a snack food.

Multi-objective optimization of bioethanol production during cold enzyme starch hydrolysis in very high gravity cassava mash.

Science.gov (United States)

Yingling, Bao; Li, Chen; Honglin, Wang; Xiwen, Yu; Zongcheng, Yan

2011-09-01

Cold enzymatic hydrolysis conditions for bioethanol production were optimized using multi-objective optimization. Response surface methodology was used to optimize the effects of α-amylase, glucoamylase, liquefaction temperature and liquefaction time on S. cerevisiae biomass, ethanol concentration and starch utilization ratio. The optimum hydrolysis conditions were: 224 IU/g(starch) α-amylase, 694 IU/g(starch) glucoamylase, 77°C and 104 min for biomass; 264 IU/g(starch) α-amylase, 392 IU/g(starch) glucoamylase, 60°C and 85 min for ethanol concentration; 214 IU/g(starch) α-amylase, 398 IU/g(starch) glucoamylase, 79°C and 117 min for starch utilization ratio. The hydrolysis conditions were subsequently evaluated by multi-objectives optimization utilizing the weighted coefficient methods. The Pareto solutions for biomass (3.655-4.380×10(8)cells/ml), ethanol concentration (15.96-18.25 wt.%) and starch utilization ratio (92.50-94.64%) were obtained. The optimized conditions were shown to be feasible and reliable through verification tests. This kind of multi-objective optimization is of potential importance in industrial bioethanol production. Copyright © 2011 Elsevier Ltd. All rights reserved.

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)

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)

Hydrolysis of maize starch using amylolytic enzymes extracted from ...

African Journals Online (AJOL)

Amylases, a-amylase (EC 3.2.1.1, α-1, 4-glucan-4-glucanohydrolase) and glucoamylase (EC 3.2.1.3, α-1, 4; α-1, 6-glucan glucohydrolase; amyloglucosidase), extracted and partially purified from sorghum malt were used to hydrolyze maize starch. The process and products of the enzymatic hydrolysis were also compared ...

Lytic Polysaccharide Monooxygenases - Studies of Fungal Secretomes and Enzyme Properties

DEFF Research Database (Denmark)

Nekiunaite, Laura

degradation, were also identified upstream the LPMO genes, providing evidence for a co-regulatory mechanism of LPMOs and amylolytic hydrolases. The second part of the PhD thesis is focused on understanding the binding properties of LPMOs to starch and starch mimic substrate. It was shown that LPMOs possessing...... to different substrates at the protein level. It could help to design better enzyme cocktails that increase efficiency of biomass degradation. The secretomes of A. nidulans revealed differences in growth and secretion of enzymes, depending on the type and properties of starches. A common characteristic...... conversion as they produce a wide diversity of degrading enzymes. In the first part of this PhD thesis, the secretomes of the well-known fungus Aspergillus nidulans grown on cereal and legume starches were analyzed. Secretomics is a powerful tool to unravel secretion patterns of fungi and their response...

Fermentation in the small intestine contributes substantially to intestinal starch disappearance in calves

NARCIS (Netherlands)

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

2015-01-01

Background: The proportion of starch disappearing from the small intestinal lumen is generally lower in ruminants than in monogastric animals, and there are indications that the starch digestion capacity in ruminants is limited. Objectives: Milk-fed calves were used to study the rate-limiting enzyme

Fermentation in the Small Intestine Contributes Substantially to Intestinal Starch Disappearance in Calves

NARCIS (Netherlands)

Gilbert, Myrthe S.; Pantophlet, Andre J.; Berends, Harma; Pluschke, Anton M.; van den Borne, Joost J. G. C.; Hendriks, Wouter H.; Schols, Henk A.; Gerrits, Walter J. J.

Background: The proportion of starch disappearing from the small intestinal lumen is generally lower in ruminants than in monogastric animals, and there are indications that the starch digestion capacity in ruminants is limited. Objectives: Milk-fed calves were used to study the rate-limiting enzyme

The phosphoglucan phosphatase like sex Four2 dephosphorylates starch at the C3-position in Arabidopsis.

Science.gov (United States)

Santelia, Diana; Kötting, Oliver; Seung, David; Schubert, Mario; Thalmann, Matthias; Bischof, Sylvain; Meekins, David A; Lutz, Andy; Patron, Nicola; Gentry, Matthew S; Allain, Frédéric H-T; Zeeman, Samuel C

2011-11-01

Starch contains phosphate covalently bound to the C6-position (70 to 80% of total bound phosphate) and the C3-position (20 to 30%) of the glucosyl residues of the amylopectin fraction. In plants, the transient phosphorylation of starch renders the granule surface more accessible to glucan hydrolyzing enzymes and is required for proper starch degradation. Phosphate also confers desired properties to starch-derived pastes for industrial applications. In Arabidopsis thaliana, the removal of phosphate by the glucan phosphatase Starch Excess4 (SEX4) is essential for starch breakdown. We identified a homolog of SEX4, LSF2 (Like Sex Four2), as a novel enzyme involved in starch metabolism in Arabidopsis chloroplasts. Unlike SEX4, LSF2 does not have a carbohydrate binding module. Nevertheless, it binds to starch and specifically hydrolyzes phosphate from the C3-position. As a consequence, lsf2 mutant starch has elevated levels of C3-bound phosphate. SEX4 can release phosphate from both the C6- and the C3-positions, resulting in partial functional overlap with LSF2. However, compared with sex4 single mutants, the lsf2 sex4 double mutants have a more severe starch-excess phenotype, impaired growth, and a further change in the proportion of C3- and C6-bound phosphate. These findings significantly advance our understanding of the metabolism of phosphate in starch and provide innovative options for tailoring novel starches with improved functionality for industry.

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

DEFF Research Database (Denmark)

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

1992-01-01

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

Effect of gelatinization and hydrolysis conditions on the selectivity of starch hydrolysis with alpha-amylase from Bacillus licheniformis

NARCIS (Netherlands)

Baks, T.; Bruins, M.E.; Matser, A.M.; Janssen, A.E.M.; Boom, R.M.

2008-01-01

Enzymatic hydrolysis of starch can be used to obtain various valuable hydrolyzates with different compositions. The effects of starch pretreatment, enzyme addition point, and hydrolysis conditions on the hydrolyzate composition and reaction rate during wheat starch hydrolysis with ¿-amylase from

The glycogen of Galdieria sulphuraria as alternative to starch for the production of slowly digestible and resistant glucose polymers

NARCIS (Netherlands)

Martinez-Garcia, Marta; Kormpa, Akrivi; van der Maarel, Marc J. E. C.

2017-01-01

Highly branched glucose polymers produced from starch are applied in various products, such as peritoneal dialysis solutions and sports drinks. Due to its insoluble, granular nature, the use of native starch as substrate requires an energy consuming pre-treatment to achieve solubilization at the

Development of enzymes and enzyme systems by genetic engineering to convert biomass to sugars

Science.gov (United States)

TITLE Development of Enzymes and Enzyme Systems by Genetic Engineering to Convert Biomass to Sugars ABSTRACT Plant cellulosic material is one of the most viable renewable resources for the world’s fuel and chemical feedstock needs. Currently ethanol derived from corn starch is the most common li...

Novel Bioengineered Cassava Expressing an Archaeal Starch Degradation System and a Bacterial ADP-Glucose Pyrophosphorylase for Starch Self-Digestibility and Yield Increase

Directory of Open Access Journals (Sweden)

Ayalew Ligaba-Osena

2018-02-01

Full Text Available To address national and global low-carbon fuel targets, there is great interest in alternative plant species such as cassava (Manihot esculenta, which are high-yielding, resilient, and are easily converted to fuels using the existing technology. In this study the genes encoding hyperthermophilic archaeal starch-hydrolyzing enzymes, α-amylase and amylopullulanase from Pyrococcus furiosus and glucoamylase from Sulfolobus solfataricus, together with the gene encoding a modified ADP-glucose pyrophosphorylase (glgC from Escherichia coli, were simultaneously expressed in cassava roots to enhance starch accumulation and its subsequent hydrolysis to sugar. A total of 13 multigene expressing transgenic lines were generated and characterized phenotypically and genotypically. Gene expression analysis using quantitative RT-PCR showed that the microbial genes are expressed in the transgenic roots. Multigene-expressing transgenic lines produced up to 60% more storage root yield than the non-transgenic control, likely due to glgC expression. Total protein extracted from the transgenic roots showed up to 10-fold higher starch-degrading activity in vitro than the protein extracted from the non-transgenic control. Interestingly, transgenic tubers released threefold more glucose than the non-transgenic control when incubated at 85°C for 21-h without exogenous application of thermostable enzymes, suggesting that the archaeal enzymes produced in planta maintain their activity and thermostability.

Control of starch content in potato

International Nuclear Information System (INIS)

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

2010-01-01

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

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.

Process development for gelatinisation and enzymatic hydrolysis of starch at high concentrations

OpenAIRE

Baks, T.

2007-01-01

cum laude graduation (with distinction) Enzymatic hydrolysis of starch is encountered in day-to-day life for instance in the dishwasher during removal of stains with detergents or in our mouth during chewing of starch-based foods in the presence of saliva. The reaction is also important for the (food) industry, for example for the production of beer or bio-ethanol. In industry, it is usually preceded by gelatinisation to make the starch molecules available for the enzymes. Both gelatinisation...

Purification and characterization of extracellular amylolytic enzyme ...

African Journals Online (AJOL)

In the present study, the amylase enzyme producing potential of four different Aspergillus species was analyzed. The extracted amylase enzyme was purified by diethyl amino ethyl (DEAE) cellulose and Sephadex G-50 column chromatography and the enzyme activity was measured by using synthetic substrate starch.

Digestion of starch in a dynamic small intestinal model.

Science.gov (United States)

Jaime-Fonseca, M R; Gouseti, O; Fryer, P J; Wickham, M S J; Bakalis, S

2016-12-01

The rate and extent of starch digestion have been linked with important health aspects, such as control of obesity and type-2 diabetes. In vitro techniques are often used to study digestion and simulated nutrient absorption; however, the effect of gut motility is often disregarded. The present work aims at studying fundamentals of starch digestion, e.g. the effect of viscosity on digestibility, taking into account both biochemical and engineering (gut motility) parameters. New small intestinal model (SIM) that realistically mimics gut motility (segmentation) was used to study digestibility and simulated oligosaccharide bio accessibility of (a) model starch solutions; (b) bread formulations. First, the model was compared with the rigorously mixed stirred tank reactor (STR). Then the effects of enzyme concentration/flow rate, starch concentration, and digesta viscosity (addition of guar gum) were evaluated. Compared to the STR, the SIM showed presence of lag phase when no digestive processes could be detected. The effects of enzyme concentration and flow rate appeared to be marginal in the region of mass transfer limited reactions. Addition of guar gum reduced simulated glucose absorption by up to 45 % in model starch solutions and by 35 % in bread formulations, indicating the importance of chyme rheology on nutrient bioaccessibility. Overall, the work highlights the significance of gut motility in digestive processes and offers a powerful tool in nutritional studies that, additionally to biochemical, considers engineering aspects of digestion. The potential to modulate food digestibility and nutrient bioaccessibility by altering food formulation is indicated.

Physicochemical properties and starch digestibility of Chinese noodles in relation to optimal cooking time.

Science.gov (United States)

Ye, Xiaoting; Sui, Zhongquan

2016-03-01

Changes in the physicochemical properties and starch digestibility of white salted noodles (WSN) at different cooking stage were investigated. The noodles were dried in fresh air and then cooked for 2-12 min by boiling in distilled water to determine the properties of cooking quality, textural properties and optical characteristic. For starch digestibility, dry noodles were milled and sieved into various particle size classes ranging from 0.5 mm to 5.0 mm, and hydrolyzed by porcine pancreatic α-amylase. The optimal cooking time of WSN determined by squeezing between glasses was 6 min. The results showed that the kinetics of solvation of starch and protein molecules were responsible for changes of the physicochemical properties of WSN during cooking. The susceptibility of starch to α-amylase was influenced by the cooking time, particle size and enzyme treatment. The greater value of rapidly digestible starch (RDS) and lower value of slowly digestible starch (SDS) and resistant starch (RS) were reached at the optimal cooking stage ranging between 63.14-71.97%, 2.47-10.74% and 23.94-26.88%, respectively, indicating the susceptibility on hydrolysis by enzyme was important in defining the cooked stage. The study suggested that cooking quality and digestibility were not correlated but the texture greatly controls the digestibility of the noodles. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Immobilized enzymes and cells

Energy Technology Data Exchange (ETDEWEB)

Bucke, C; Wiseman, A

1981-04-04

This article reviews the current state of the art of enzyme and cell immobilization and suggests advances which might be made during the 1980's. Current uses of immobilized enzymes include the use of glucoamylase in the production of glucose syrups from starch and glucose isomerase in the production of high fructose corn syrup. Possibilities for future uses of immobilized enzymes and cells include the utilization of whey and the production of ethanol.

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

DEFF Research Database (Denmark)

Blennow, A.; Svensson, Birte

2010-01-01

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

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.

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.

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.

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.

Milling of rice grains: effects of starch/flour structures on gelatinization and pasting properties.

Science.gov (United States)

Hasjim, Jovin; Li, Enpeng; Dhital, Sushil

2013-01-30

Starch gelatinization and flour pasting properties were determined and correlated with four different levels of starch structures in rice flour, i.e. flour particle size, degree of damaged starch granules, whole molecular size, and molecular branching structure. Onset starch-gelatinization temperatures were not significantly different among all flour samples, but peak and conclusion starch-gelatinization temperatures were significantly different and were strongly correlated with the flour particle size, indicating that rice flour with larger particle size has a greater barrier for heat transfer. There were slight differences in the enthalpy of starch gelatinization, which are likely associated with the disruption of crystalline structure in starch granules by the milling processes. Flours with volume-median diameter ≥56 μm did not show a defined peak viscosity in the RVA viscogram, possibly due to the presence of native protein and/or cell-wall structure stabilizing the swollen starch granules against the rupture caused by shear during heating. Furthermore, RVA final viscosity of flour was strongly correlated with the degree of damage to starch granules, suggesting the contribution of granular structure, possibly in swollen form. The results from this study allow the improvement in the manufacture and the selection criteria of rice flour with desirable gelatinization and pasting properties. Copyright © 2012 Elsevier Ltd. All rights reserved.

VAPOR MIXER FOR GELATINIZATION OF STARCH IN LIQUEFYING STATION

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V. V. Ananskikh

2015-01-01

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

Investigation of digestion Kinetics in commercial starches using in-situ small-angle neutron scattering

International Nuclear Information System (INIS)

Blazek, Jaroslav; Gilbert, Elliot Paul

2009-01-01

Full text: The digestion of starch has been the subject of many investigations, mostly involving in vitro measurement of the susceptibility of starches to attack by different enzymes, rather than measuring actual digestibility in vivo. The rate and extent of amylolytic hydrolysis of granular starches is known to vary according to botanical origin. Granule characteristics considered to influence susceptibility to attack by alpha-amylase include crystallinity, granule size and available specific surface, amylose content, porosity, structural inhomogeneities and degree of integrity. Most in-vitro studies of granular starch digestion have been limited to samples for which aliquots have been removed from the reaction mixture at various time intervals and freeze-dried to be subsequently characterized using a range of techniques. It remains unclear whether sample preparation creates artefacts in the samples. In this study, we have studied the kinetics of starch digestion of several commercial granular starches by time-resolved small-angle neutron scattering using an in-situ digestion chamber allowing, for the first time, to follow structural changes of starch in the course of digestion directly in the digestion mixture. Additionally, samples before and after digestion were studied by x-ray diffraction, small-angle x-ray scattering, differential scanning calorimetry and microscopy. Microscopy revealed that studied starches, which varied in their amylose content and digestion kinetics, followed different modes of attack The multidisciplinary approach allowed the nanostructural changes detected by small-angle scattering in the course of enzymic breakdown to be correlated with changes in crystallinity and functional properties.

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.

DEXTRINIZED SYRUPS OBTAINING THROUGH THE ENZYMATIC HYDROLYSIS OF SORGHUM STARCH

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Leyanis Rodríguez Rodríguez

2015-10-01

Full Text Available The main objective of this work was the production of syrups dextrinized by enzymatic hydrolysis of starch red sorghum CIAPR-132 using α-amylase on solutions at different concentrations, with different concentrations of enzyme and enzyme hydrolysis time. The response variable was the dextrose equivalent in each obtained syrup (ED using the modified Lane-Eynon method. In some of the experiments, we used a full factorial design 23 and in others we worked with intermediate concentration and higher hydrolysis time with different levels of enzyme. The obtained products were syrups dextrinized ED between 10,25 and 33,97% (values we can find within the established ones for these types of syrups, which can be used for their functional properties as intermediates syrups or as raw material for different processes of the food industry. This allows you to set a pattern for the use of sorghum feedstock in unconventional obtaining products from its starch.

Brewing Science in the Chemistry Laboratory: A "Mashing" Investigation of Starch and Carbohydrates

Science.gov (United States)

Pelter, Michael W.; McQuade, Jennifer

2005-01-01

The experiments that mimic the actual brewing process to explain the science to the nonscience majors is performed using malted barley as the source for both the starch and the amylase enzyme. The experiment introduces the concept of monitoring the progress of chemical reaction and was able to show the chemical breakdown of the starch to simple…

Resistant starch: an indigestible fraction of foods

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Saura Calixto, F.

1991-06-01

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

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

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

Science.gov (United States)

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

2017-10-23

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

Identification and characterization of starch and inulin modifying network of Aspergillus niger by functional genomics

NARCIS (Netherlands)

Yuan, Xiao-Lian

2008-01-01

Aspergillus niger produces a wide variety of carbohydrate hydrolytic enzymes which have potential applications in the baking, starch, textile, food and feed industries. The goal of this thesis is to unravel the molecular mechanisms of starch and inulin modifying network of A. niger, in order to

Effect of Barley and Enzyme on Performance, Carcass, Enzyme Activity and Digestion Parameters of Broilers

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majid kalantar

2016-04-01

Full Text Available Introduction Corn has been recently used for producing ethanol fuel in the major corn-producing countries such as the US and Brazil. Recent diversion of corn for biofuel production along with the increased world's demand for this feedstuff has resulted in unprecedented rise in feed cost for poultry worldwide. Alternative grains such as wheat and barley can be successfully replaced for corn in poultry diets. These cereal grains can locally grow in many parts of the world as they have remarkably lower water requirement than corn. Wheat and barley are generally used as major sources of energy in poultry diets. Though the major components of these grains are starch and proteins, they have considerable content of non-starch polysaccharides (NSPs, derived from the cell walls (Olukosi et al. 2007; Mirzaie et al. 2012. NSPs are generally considered as anti-nutritional factors (Jamroz et al. 2002. The content and structure of NSP polymers vary between different grains, which consequently affect their nutritive value (Olukosi et al. 2007.Wheat and barley are generally used as major sources of energy in poultry diets. The major components of these grains are starch and proteins, they have considerable content of non-starch polysaccharides (NSPs, derived from the cell walls. NSPs are generally considered as anti-nutritional factors. The content and structure of NSP polymers vary between different grains, which consequently affect their nutritive value. The major part of NSPs in barley comprises polymers of (1→3 (1→4-β- glucans which could impede growth factors and consequently carcass quality through lowering the rate and amount of available nutrients in the mucosal surface of the intestinal. Materials and Methods This experiment was conducted to evaluate the effect of corn and barley based diets supplemented with multi-enzyme on growth, carcass, pancreas enzyme activity and physiological characteristics of broilers. A total number of 375 one day old

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

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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

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

Science.gov (United States)

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

2009-04-01

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

HYDROLYSIS OF STARCH BY THERMO-AND PH-STABLE GLUCOAMYLASE AT CHANGE PHYSICO-CHEMICAL FACTORS

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V. S. Grigirov

2013-01-01

Full Text Available Regularity of the change rate of the enzymatic reactions depending on different temperatures, pH values in the formation and decay of the enzyme-substrate complex was investigated. Found that the kinetics of hydrolysis of starch by the action of heat and pH stable glucoamylases is complex as evidenced by the change in the value Km, which is a measure of the affinity of the enzyme to the substrate, active centers studied glucoamylases and starch undergo conformational changes at pH 4,0-5,0; 4,5-5,5 and a temperature of 60-65 °C.

Isolation and characterization of the gene encoding the starch debranching enzyme limit dextrinase from germinating barley

DEFF Research Database (Denmark)

Kristensen, Michael; Lok, Finn; Planchot, Véronique

1999-01-01

with a value of 105 kDa estimated by SDS;;PAGE, The coding sequence is interrupted by 26 introns varying in length from 93 bp to 825 bp. The 27 exons vary in length from 53 bp to 197 bp. Southern blot analysis shows that the limit dextrinase gene is present as a single copy in the barley genome. Gene......The gene encoding the starch debranching enzyme limit dextrinase, LD, from barley (Hordeum vulgare), was isolated from a genomic phage library using a barley cDNA clone as probe. The gene encodes a protein of 904 amino acid residues with a calculated molecular mass of 98.6 kDa. This is in agreement...... expression is high during germination and the steady state transcription level reaches a maximum at day 5 of germination. The deduced amino acid sequence corresponds to the protein sequence of limit dextrinase purified from germinating malt, as determined by automated N-terminal sequencing of tryptic...

Effects of thermo-resistant non-starch polysaccharide degrading multi-enzyme on growth performance, meat quality, relative weights of body organs and blood profile in broiler chickens.

Science.gov (United States)

Mohammadi Gheisar, M; Hosseindoust, A; Kim, I H

2016-06-01

This research was conducted to study the performance and carcass parameters of broiler chickens fed diets supplemented with heat-treated non-starch polysaccharide degrading enzyme. A total of 432 one-day old Ross 308 broiler chickens were allocated to five treatments: (i) CON (basal diet), (ii) E1: CON + 0.05% multi-enzyme, (iii) E2: CON + 0.1% multi-enzyme, (iv) E3: CON + 0.05% thermo-resistant multi-enzyme and (v) E4: CON + 0.1% thermo-resistant multi-enzyme, each treatment consisted of six replications and 12 chickens in each replication. The chickens were housed in three floor battery cages during 28-day experimental period. On days 1-7, gain in body weight (BWG) improved by feeding the diets supplemented with thermo-resistant multi-enzyme. On days 7-21 and 1-28, chickens fed the diets containing thermo-resistant multi-enzyme showed improved (p thermo-resistant multi-enzyme affected the percentage of drip loss on d 1 (p thermo-resistant multi-enzyme did not affect the relative weights of organs but compared to CON group, relative weight of breast muscle increased and abdominal fat decreased (p thermo-resistant multi-enzyme showed higher (p thermo-resistant multi-enzyme improved performance of broiler chickens. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

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

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Kai Zhang

2017-06-01

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

Towards an optimal process for gelatinisation and hydrolysis of highly concentrated starch-water mixtures with alpha-amylase from B. licheniformis

NARCIS (Netherlands)

Baks, T.; Kappen, F.H.J.; Janssen, A.E.M.; Boom, R.M.

2008-01-01

The enzymatic hydrolysis of starch is usually carried out with 30¿35 w/w% starch in water. Higher substrate concentrations (50¿70 w/w%) were reached by using a twin-screw extruder for gelatinisation and for mixing enzyme with gelatinised starch prior to enzymatic hydrolysis in a batch reactor. The

Low-temperature effect on enzyme activities involved in sucrose-starch partitioning in salt-stressed and salt-acclimated cotyledons of quinoa (Chenopodium quinoa Willd.) seedlings.

Science.gov (United States)

Rosa, Mariana; Hilal, Mirna; González, Juan A; Prado, Fernando E

2009-04-01

The effect of low temperature on growth, sucrose-starch partitioning and related enzymes in salt-stressed and salt-acclimated cotyledons of quinoa (Chenopodium quinoa Willd.) was studied. The growth of cotyledons and growing axes in seedlings grown at 25/20 degrees C (light/dark) and shifted to 5/5 degrees C was lower than in those only growing at 25/20 degrees C (unstressed). However, there were no significant differences between low-temperature control and salt-treated seedlings. The higher activities of sucrose phosphate synthase (SPS, EC 2.4.1.14) and soluble acid invertase (acid INV, EC 3.2.1.25) were observed in salt-stressed cotyledons; however, the highest acid INV activity was observed in unstressed cotyledons. ADP-glucose pyrophosphorylase (ADP-GPPase, EC 2.7.7.27) was higher in unstressed cotyledons than in stressed ones. However, between 0 and 4days the highest value was observed in salt-stressed cotyledons. The lowest value of ADP-GPPase was observed in salt-acclimated cotyledons. Low temperature also affected sucrose synthase (SuSy, EC 2.4.1.13) activity in salt-treated cotyledons. Sucrose and glucose were higher in salt-stressed cotyledons, but fructose was essentially higher in low-temperature control. Starch was higher in low-temperature control; however, the highest content was observed at 0day in salt-acclimated cotyledons. Results demonstrated that low temperature induces different responses on sucrose-starch partitioning in salt-stressed and salt-acclimated cotyledons. Data also suggest that in salt-treated cotyledons source-sink relations (SSR) are changed in order to supply soluble sugars and proline for the osmotic adjustment. Relationships between starch formation and SuSy activity are also discussed.

Improvement of raw starch digestibility by ion-beam mutation of Aspergillus awamori

Energy Technology Data Exchange (ETDEWEB)

Amsal, Aryanti [National Atomic Energy Agency, Jakarta (Indonesia); Takigami, Machiko; Ito, Hitoshi

1998-09-01

Aspergillus awamori possess the ability to express raw starch digestibility. For the effective utilization of starchy crops produced in South-Asian countries, it is important to achieve the digestion of raw starchs for industrial fermentation process. In this study, higher ratio of mutant strains of Aspergillus awamori IFO4033 were isolated by irradiation of C{sup 5+} ion-beam on freeze dried spores with improvement of enzyme production for two-to threefold in the extracellular {alpha}-amylase compared with gamma-irradiation. The digestibility of raw starch from cassava, sago and sukun increased remarkably about two-to threefold by some mutant strains obtained from irradiation of C{sup 5+} ion-beam. (author)

Improvement of raw starch digestibility by ion-beam mutation of Aspergillus awamori

International Nuclear Information System (INIS)

Amsal, Aryanti; Takigami, Machiko; Ito, Hitoshi

1998-01-01

Aspergillus awamori possess the ability to express raw starch digestibility. For the effective utilization of starchy crops produced in South-Asian countries, it is important to achieve the digestion of raw starchs for industrial fermentation process. In this study, higher ratio of mutant strains of Aspergillus awamori IFO4033 were isolated by irradiation of C 5+ ion-beam on freeze dried spores with improvement of enzyme production for two-to threefold in the extracellular α-amylase compared with gamma-irradiation. The digestibility of raw starch from cassava, sago and sukun increased remarkably about two-to threefold by some mutant strains obtained from irradiation of C 5+ ion-beam. (author)

The effect of baking and enzymatic treatment on the structural properties of wheat starch.

Science.gov (United States)

Fuentes, Catalina; Zielke, Claudia; Prakash, Manish; Kumar, Puneeth; Peñarrieta, J Mauricio; Eliasson, Ann-Charlotte; Nilsson, Lars

2016-12-15

In this study, bread was baked with and without the addition of α-amylase. Starch was extracted from the baked bread and its molecular properties were characterized using (1)H NMR and asymmetric flow field-flow fractionation (AF4) connected to multi-angle light scattering (MALS) and other detectors. The approach allows determination of molar mass, root- mean-square radius and apparent density as well as the average degree of branching of amylopectin. The results show that starch size and structure is affected as a result of the baking process. The effect is larger when α-amylase is added. The changes include both a decrease molar mass and size as well as an increase in apparent density. Moreover, an increase in average degree of branching and the number of reducing ends H-1(β-r) and H-1(α-r) can be observed. Copyright © 2016. Published by Elsevier Ltd.

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

Science.gov (United States)

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

2016-10-20

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

Modificação enzimática da farinha de arroz visando a produção de amido resistente Enzymatic modification on rice flour seeking the production of resitant starch

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Márcio Garcia Severo

2010-01-01

Full Text Available The aim of this work was to study the enzymatic modification on rice flour using lipase pancreatic and amyloglucosidase to obtain resistant starch. For this, Response Surface Methodology (RSM was used to determine the best operating conditions for each enzyme. For lypase pancreatic, the highest value for resistant starch (45% was achieved within 2 h reaction at pH 7 using an enzyme/substrate ratio of 4% (w/w and Dp= 100/200 tyler. For amyloglucosidase, optima conditions corresponded to an enzyme/substrate ratio of 0,006 mL/g and Dp= 100/200 tyler at 45 ºC, yielding 57% of resistant starch in 2 h reaction. These results show the potential of using both enzymes to modified rice flour, increasing the resistant starch in about 5.7 folds in relation to the flour without treatment (resistant starch=10.6%.

Production of Active Bacillus licheniformis Alpha-Amylase in Tobacco and its Application in Starch Liquefaction

NARCIS (Netherlands)

Pen, J; MOLENDIJK, L; Quax, Wim J.; SIJMONS, PC; VANOOYEN, AJJ; VANDENELZEN, PJM; RIETVELD, K; HOEKEMA, A

As a first example of the feasibility of producing industrial bulk enzymes in plants, we have expressed Bacillus licheniformis alpha-amylase in transgenic tobacco, and applied the seeds directly in starch liquification. The enzyme was properly secreted into the intercellular space, and maximum

Fermentation Results and Chemical Composition of Agricultural Distillates Obtained from Rye and Barley Grains and the Corresponding Malts as a Source of Amylolytic Enzymes and Starch.

Science.gov (United States)

Balcerek, Maria; Pielech-Przybylska, Katarzyna; Dziekońska-Kubczak, Urszula; Patelski, Piotr; Strąk, Ewelina

2016-10-01

The objective of this study was to determine the efficiency of rye and barley starch hydrolysis in mashing processes using cereal malts as a source of amylolytic enzymes and starch, and to establish the volatile profile of the obtained agricultural distillates. In addition, the effects of the pretreatment method of unmalted cereal grains on the physicochemical composition of the prepared mashes, fermentation results, and the composition of the obtained distillates were investigated. The raw materials used were unmalted rye and barley grains, as well as the corresponding malts. All experiments were first performed on a semi-technical scale, and then verified under industrial conditions in a Polish distillery. The fermentable sugars present in sweet mashes mostly consisted of maltose, followed by glucose and maltotriose. Pressure-thermal treatment of unmalted cereals, and especially rye grains, resulted in higher ethanol content in mashes in comparison with samples subjected to pressureless liberation of starch. All agricultural distillates originating from mashes containing rye and barley grains and the corresponding malts were characterized by low concentrations of undesirable compounds, such as acetaldehyde and methanol. The distillates obtained under industrial conditions contained lower concentrations of higher alcohols (apart from 1-propanol) than those obtained on a semi-technical scale.

Fermentation Results and Chemical Composition of Agricultural Distillates Obtained from Rye and Barley Grains and the Corresponding Malts as a Source of Amylolytic Enzymes and Starch

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Maria Balcerek

2016-10-01

Full Text Available The objective of this study was to determine the efficiency of rye and barley starch hydrolysis in mashing processes using cereal malts as a source of amylolytic enzymes and starch, and to establish the volatile profile of the obtained agricultural distillates. In addition, the effects of the pretreatment method of unmalted cereal grains on the physicochemical composition of the prepared mashes, fermentation results, and the composition of the obtained distillates were investigated. The raw materials used were unmalted rye and barley grains, as well as the corresponding malts. All experiments were first performed on a semi-technical scale, and then verified under industrial conditions in a Polish distillery. The fermentable sugars present in sweet mashes mostly consisted of maltose, followed by glucose and maltotriose. Pressure-thermal treatment of unmalted cereals, and especially rye grains, resulted in higher ethanol content in mashes in comparison with samples subjected to pressureless liberation of starch. All agricultural distillates originating from mashes containing rye and barley grains and the corresponding malts were characterized by low concentrations of undesirable compounds, such as acetaldehyde and methanol. The distillates obtained under industrial conditions contained lower concentrations of higher alcohols (apart from 1-propanol than those obtained on a semi-technical scale.

Responses of Landoltia punctata to cobalt and nickel: Removal, growth, photosynthesis, antioxidant system and starch metabolism.

Science.gov (United States)

Guo, Ling; Ding, Yanqiang; Xu, Yaliang; Li, Zhidan; Jin, Yanling; He, Kaize; Fang, Yang; Zhao, Hai

2017-09-01

Landoltia punctata has been considered as a potential bioenergy crop due to its high biomass and starch yields in different cultivations. Cobalt and nickel are known to induce starch accumulation in duckweed. We monitored the growth rate, net photosynthesis rate, total chlorophyll content, Rubisco activity, Co 2+ and Ni 2+ contents, activity of antioxidant enzymes, starch content and activity of related enzymes under various concentrations of cobalt and nickel. The results indicate that Co 2+ and Ni 2+ (≤0.5mgL -1 ) can facilitate growth in the beginning. Although the growth rate, net photosynthesis rate, chlorophyll content and Rubisco activity were significantly inhibited at higher concentrations (5mgL -1 ), the starch content increased sharply up to 53.3% dry weight (DW) in L. punctata. These results were attributed to the increase in adenosine diphosphate-glucose pyrophosphorylase (AGPase) and soluble starch synthase (SSS) activities and the decrease in α-amylase activity upon exposure to excess Co 2+ and Ni 2+ . In addition, a substantial increase in the antioxidant enzyme activities and high flavonoid contents in L. punctata may have largely resulted in the metal tolerance. Furthermore, the high Co 2+ and Ni 2+ contents (2012.9±18.8 and 1997.7±29.2mgkg -1 DW) in the tissue indicate that L. punctata is a hyperaccumulator. Thus, L. punctata can be considered as a potential candidate for the simultaneous bioremediation of Co 2+ - and Ni 2+ -polluted water and high-quality biomass production. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

2015-01-22

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

Production of fructose-containing syrup with enzymes

Energy Technology Data Exchange (ETDEWEB)

Helwiig-Nielsen, B

1981-01-01

A review on enzymic processes used for production of fructose- high syrup from starch including liquefaction by alpha-amylase, saccharification by amyloglucosidase, and isomerization with glucose isomerase.

Effect of thermostable α-amylase injection on mechanical and physiochemical properties for saccharification of extruded corn starch.

Science.gov (United States)

Myat, Lin; Ryu, Gi-Hyung

2014-01-30

In industry, a jet cooker is used to gelatinize starch by mixing the starch slurry with steam under pressure at 100-175 °C. A higher degree of starch hydrolysis in an extruder is possible with glucoamylase. Unfortunately, it is difficult to carry out liquefaction and saccharification in parallel, because the temperature of gelatinization will be too high and will inactivate glucoamylase. Since the temperature for liquefaction and saccharification is different, it is hard to change the temperature from high (required for liquefaction) to low (required for saccharification). The industrial gelatinization process is usually carried out with 30-35% (w/w) dry solids starch slurry. Conventional jet cookers cannot be used any more at high substrate concentrations owing to higher viscosity. In this study, therefore, corn starch was extruded at different melt temperatures to overcome these limitations and to produce the highest enzyme-accessible starch extrudates. Significant effects on physical properties (water solubility index, water absorption index and color) and chemical properties (reducing sugar and % increase in reducing sugar after saccharification) were achieved by addition of thermostable α-amylase at melt temperatures of 115 and 135 °C. However, there was no significant effect on % increase in reducing sugar of extruded corn starch at 95 °C. The results show the great potential of extrusion with thermostable α-amylase injection at 115 and 135 °C as an effective pretreatment for breaking down starch granules, because of the significant increase (P < 0.05) in % reducing sugar and enzyme-accessible extrudates for saccharification yield. © 2013 Society of Chemical Industry.

Degradation and Moisture Absorption Study of Potato-starch Linear ...

African Journals Online (AJOL)

Composite of linear low density polyethylene (LLDPE) and potato-starch was produced and subjected to degradation studies with the agencies of enzymes, exposure to weather and immersion in water. Enzymatic hydrolysis degraded the matrix to an extent greater than 40% loss in strength and about 20% loss in ...

Effect of Multiple Freezing/Thawing Cycles on the Structural and Functional Properties of Waxy Rice Starch

Science.gov (United States)

Tao, Han; Yan, Juan; Zhao, Jianwei; Tian, Yaoqi; Jin, Zhengyu; Xu, Xueming

2015-01-01

The structural and functional properties of non-gelatinized waxy rice starch were investigated after 1, 3, 7, and 10 freezing/thawing cycles. Freezing caused an increasing damaged starch from 1.36% in native waxy rice starch to 5.77% in 10 freezing/thawing-treated starch (FTS), as evidenced by the cracking surface on starch granules. More dry matter concentration was leached, which was characterized by high amylopectin concentration (4.34 mg/mL). The leaching was accompanied by a decrease in relative crystallinity from 35.19% in native starch to 31.34% in 10 FTS. Freezing treatment also led to significant deviations in the functional characteristics, for instance decreased gelatinization temperature range, enthalpy, and pasting viscosities. The resistant starch content of 10FTS significantly decreased from 58.9% to 19%, whereas the slowly digested starch content greatly increased from 23.8% in native starch to 50.3%. The increase in susceptibility to enzyme hydrolysis may be attributed to porous granular surface, amylopectin leaching, and the decrease in the relative crystallinity caused by freezing water. PMID:26018506

Effect of multiple freezing/thawing cycles on the structural and functional properties of waxy rice starch.

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Han Tao

Full Text Available The structural and functional properties of non-gelatinized waxy rice starch were investigated after 1, 3, 7, and 10 freezing/thawing cycles. Freezing caused an increasing damaged starch from 1.36% in native waxy rice starch to 5.77% in 10 freezing/thawing-treated starch (FTS, as evidenced by the cracking surface on starch granules. More dry matter concentration was leached, which was characterized by high amylopectin concentration (4.34 mg/mL. The leaching was accompanied by a decrease in relative crystallinity from 35.19% in native starch to 31.34% in 10 FTS. Freezing treatment also led to significant deviations in the functional characteristics, for instance decreased gelatinization temperature range, enthalpy, and pasting viscosities. The resistant starch content of 10FTS significantly decreased from 58.9% to 19%, whereas the slowly digested starch content greatly increased from 23.8% in native starch to 50.3%. The increase in susceptibility to enzyme hydrolysis may be attributed to porous granular surface, amylopectin leaching, and the decrease in the relative crystallinity caused by freezing water.

Two Strategies for Microbial Production of an Industrial Enzyme-Alpha-Amylase

Science.gov (United States)

Bernhardsdotter, Eva C. M. J.; Garriott, Owen; Pusey, Marc L.; Ng, Joseph D.

2003-01-01

Extremophiles are microorganisms that thrive in, from an anthropocentric view, extreme environments including hot springs, soda lakes and arctic water. This ability of survival at extreme conditions has rendered extremophiles to be of interest in astrobiology, evolutionary biology as well as in industrial applications. Of particular interest to the biotechnology industry are the biological catalysts of the extremophiles, the extremozymes, whose unique stabilities at extreme conditions make them potential sources of novel enzymes in industrial applications. There are two major approaches to microbial enzyme production. This entails enzyme isolation directly from the natural host or creating a recombinant expression system whereby the targeted enzyme can be overexpressed in a mesophilic host. We are employing both methods in the effort to produce alpha-amylases from a hyperthermophilic archaeon (Thermococcus) isolated from a hydrothermal vent in the Atlantic Ocean, as well as from alkaliphilic bacteria (Bacillus) isolated from a soda lake in Tanzania. Alpha-amylases catalyze the hydrolysis of internal alpha-1,4-glycosidic linkages in starch to produce smaller sugars. Thermostable alpha-amylases are used in the liquefaction of starch for production of fructose and glucose syrups, whereas alpha-amylases stable at high pH have potential as detergent additives. The alpha-amylase encoding gene from Thermococcus was PCR amplified using carefully designed primers and analyzed using bioinformatics tools such as BLAST and Multiple Sequence Alignment for cloning and expression in E.coli. Four strains of Bacillus were grown in alkaline starch-enriched medium of which the culture supernatant was used as enzyme source. Amylolytic activity was detected using the starch-iodine method.

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

Science.gov (United States)

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

2018-03-01

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

Some Nutritional Characteristics of Enzymatically Resistant Maltodextrin from Cassava (Manihot esculenta Crantz) Starch.

Science.gov (United States)

Toraya-Avilés, Rocío; Segura-Campos, Maira; Chel-Guerrero, Luis; Betancur-Ancona, David

2017-06-01

Cassava (Manihot esculenta Crantz) native starch was treated with pyroconversion and enzymatic hydrolysis to produce a pyrodextrin and an enzyme-resistant maltodextrin. Some nutritional characteristics were quantified for both compounds. Pyroconversion was done using a 160:1 (p/v) starch:HCl ratio, 90 °C temperature and 3 h reaction time. The resulting pyrodextrin contained 46.21% indigestible starch and 78.86% dietary fiber. Thermostable α-amylase (0.01%) was used to hydrolyze the pyrodextrin at 95 °C for 5 min. The resulting resistant maltodextrin contained 24.45% dextrose equivalents, 56.06% indigestible starch and 86.62% dietary fiber. Compared to the cassava native starch, the pyrodextrin exhibited 56% solubility at room temperature and the resistant maltodextrin 100%. The glycemic index value for the resistant maltodextrin was 59% in healthy persons. Its high indigestible starch and dietary fiber contents, as well as its complete solubility, make the resistant maltodextrin a promising ingredient for raising dietary fiber content in a wide range of foods, especially in drinks, dairy products, creams and soups.

Effect of starch isolation method on properties of sweet potato starch

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A. SURENDRA BABU

2014-08-01

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

Production of saccharifying enzyme using the wastewater of a shochu distillery

Energy Technology Data Exchange (ETDEWEB)

Morimura, S.; Kida, K.; Yakita, Y.; Sonoda, Y. (Kumamoto University, Kumamoto (Japan). Faculty of Engineering); Myoga, H. (Organo Co. LTd., Tokyo (Japan))

1991-05-25

A saccharifying enzyme was produced using wastewater from a shochu distillery. Since the wastewater contained highly concentrated volatile fatty acids and those severely inhibited cell growth at low pH as converted to their free forms, the initial pH ranging from 4.5 to 6.0 was optimum. It was suggested that cell autolysis facilitated the release of the saccharifying enzyme, however, a released protease digested the enzyme with a subsequent decrease in activity. The enzyme was purified easily, and the purified enzyme was homogeneous as analyzed by disc electrophoresis. The enzyme was characterized by a molecular weight of 54,000 Da, an isoelectric point of pH 3.6, and the optimum reaction temperature and pH of 50-55{degree}C and 4.5-5.5, respectively. The enzyme could digest no raw starch, and the hydrolyzate of soluble starch by the enzyme was composed of two to four oligosaccharides. Based on above results and the amino acid sequence in a N-terminal, the enzyme produced was concluded to be {alpha}-amylase. 11 refs., 8 figs., 6 tabs.

Identification and phylogenetic analysis of a novel starch synthase in maize

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Hanmei eLiu

2015-11-01

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

Fragrance Release from the Surface of Branched Poly (Amide S

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T. Youngs

2005-01-01

Full Text Available Enzymes are powerful tools in organic synthesis that are able to catalyse a wide variety of selective chemical transformations under mild and environmentally friendly conditions. Enzymes such as the lipases have also found applications in the synthesis and degradation of polymeric materials. However, the use of these natural catalysts in the synthesis and the post-synthetic modification of dendrimers and hyperbranched molecules is an application of chemistry yet to be explored extensively. In this study the use of two hydrolytic enzymes, a lipase from Candida cylindracea and a cutinase from Fusarium solani pisii, were investigated in the selective cleavage of ester groups situated on the peripheral layer of two families of branched polyamides. These branched polyamides were conjugated to simple fragrances citronellol and L-menthol via ester linkages. Hydrolysis of the ester linkage between the fragrances and the branched polyamide support was carried out in aqueous buffered systems at slightly basic pH values under the optimum operative conditions for the enzymes used. These preliminary qualitative investigations revealed that partial cleavage of the ester functionalities from the branched polyamide support had occurred. However, the ability of the enzymes to interact with the substrates decreased considerably as the branching density, the rigidity of the structure and the bulkiness of the polyamide-fragrance conjugates increased.

The activity of barley alpha-amylase on starch granules is enhanced by fusion of a starch binding domain from Aspergillus niger glucoamylase

DEFF Research Database (Denmark)

Juge, N.; Nøhr, J.; Le Gal-Coëffet, M.-F.

2006-01-01

High affinity for starch granules of certain amylolytic enzymes is mediated by a separate starch binding domain (SBD). In Aspergillus niger glucoamylase (GA-I), a 70 amino acid O-glycosylated peptide linker connects SBD with the catalytic domain. A gene was constructed to encode barley alpha......-amylase 1 (AMY1) fused C-terminally to this SBD via a 37 residue GA-I linker segment. AMY1-SBD was expressed in A. niger, secreted using the AMY1 signal sequence at 25 mg x L(-1) and purified in 50% yield. AMY1-SBD contained 23% carbohydrate and consisted of correctly N-terminally processed multiple forms...... in A. niger). AMY1-SBD showed a 2-fold increased activity for soluble starch at low (0.5%) but not at high (1%) concentration. AMY1-SBD hydrolysed amylose DP440 with an increased degree of multiple attack of 3 compared to 1.9 for rAMY1. Remarkably, at low concentration (2 nM), AMY1-SBD hydrolysed...

Surface-assisted DNA self-assembly: An enzyme-free strategy towards formation of branched DNA lattice

International Nuclear Information System (INIS)

Bhanjadeo, Madhabi M.; Nayak, Ashok K.; Subudhi, Umakanta

2017-01-01

DNA based self-assembled nanostructures and DNA origami has proven useful for organizing nanomaterials with firm precision. However, for advanced applications like nanoelectronics and photonics, large-scale organization of self-assembled branched DNA (bDNA) into periodic lattices is desired. In this communication for the first time we report a facile method of self-assembly of Y-shaped bDNA nanostructures on the cationic surface of Aluminum (Al) foil to prepare periodic two dimensional (2D) bDNA lattice. Particularly those Y-shaped bDNA structures having smaller overhangs and unable to self-assemble in solution, they are easily assembled on the surface of Al foil in the absence of ligase. Field emission scanning electron microscopy (FESEM) analysis shows homogenous distribution of two-dimensional bDNA lattices across the Al foil. When the assembled bDNA structures were recovered from the Al foil and electrophoresed in nPAGE only higher order polymeric bDNA structures were observed without a trace of monomeric structures which confirms the stability and high yield of the bDNA lattices. Therefore, this enzyme-free economic and efficient strategy for developing bDNA lattices can be utilized in assembling various nanomaterials for functional molecular components towards development of DNA based self-assembled nanodevices. - Highlights: • Al foil surface-assisted self-assembly of monomeric structures into larger branched DNA lattice. • FESEM study confirms the uniform distribution of two-dimensional bDNA lattice structures across the surface of Al foil. • Enzyme-free and economic strategy to prepare higher order structures from simpler DNA nanostructures have been confirmed by recovery assay. • Use of well proven sequences for the preparation of pure Y-shaped monomeric DNA nanostructure with high yield.

Physical and biological treatments of polyethylene-rice starch plastic films

Energy Technology Data Exchange (ETDEWEB)

El-Naggar, Manal M.A., E-mail: mmelnaggar@yahoo.com [Microbiology Lab., National Institute of Oceanography and Fisheries, Alexandria (Egypt); Farag, Magdy Gh. [Development Plastic Center, Victoria, Alexandria (Egypt)

2010-04-15

This study aimed to produce an industrial applicable thermo-stable {alpha}-amylase from marine Bacillus amyloliquefaciens which isolated and selected according to its significant enzyme production. The effect of different pH values and temperatures on the bacterial growth and the enzyme production was estimated using an experimental statistical design; maximum amylase production and bacterial growth was obtained at pH 7.0 and 50 deg. C. Some biodegradable polyethylene rice starch plastic films (PERS-P) were manufactured using 0, 2.5, 5, 7.5 and 10% starch concentrations. The biodegradability (reduction in the plastic elongation%) was tested using the exposure to UV radiation at {lambda}{sub 300-400nm} (intensity of about 1000 W/m{sup 2}) and the produced B. amyloliquefaciens thermo-stable {alpha}-amylase. A significant reduction in the elongation% of these biodegradable plastics was observed in both cases especially on testing the 10% PERS-P; they showed a reduction of 26% and 20%, respectively, compared to the untreated plastic films (180 {+-} 5).

Physical and biological treatments of polyethylene-rice starch plastic films

International Nuclear Information System (INIS)

El-Naggar, Manal M.A.; Farag, Magdy Gh.

2010-01-01

This study aimed to produce an industrial applicable thermo-stable α-amylase from marine Bacillus amyloliquefaciens which isolated and selected according to its significant enzyme production. The effect of different pH values and temperatures on the bacterial growth and the enzyme production was estimated using an experimental statistical design; maximum amylase production and bacterial growth was obtained at pH 7.0 and 50 deg. C. Some biodegradable polyethylene rice starch plastic films (PERS-P) were manufactured using 0, 2.5, 5, 7.5 and 10% starch concentrations. The biodegradability (reduction in the plastic elongation%) was tested using the exposure to UV radiation at λ 300-400nm (intensity of about 1000 W/m 2 ) and the produced B. amyloliquefaciens thermo-stable α-amylase. A significant reduction in the elongation% of these biodegradable plastics was observed in both cases especially on testing the 10% PERS-P; they showed a reduction of 26% and 20%, respectively, compared to the untreated plastic films (180 ± 5).

Internal structure of normal maize starch granules revealed by chemical surface gelatinization.

Science.gov (United States)

Pan, D D; Jane, J I

2000-01-01

Normal maize starch was fractionated into two sizes: large granules with diameters more than 5 microns and small granules with diameters less than 5 microns. The large granules were surface gelatinized by treating them with an aqueous LiCl solution (13 M) at 22-23 degrees C. Surface-gelatinized remaining granules were obtained by mechanical blending, and gelatinized surface starch was obtained by grinding with a mortar and a pestle. Starches of different granular sizes and radial locations, obtained after different degrees of surface gelatinization, were subjected to scanning electron microscopy, iodine potentiometric titration, gel-permeation chromatography, and amylopectin branch chain length analysis. Results showed that the remaining granules had a rough surface with a lamella structure. Amylose was more concentrated at the periphery than at the core of the granule. Amylopectin had longer long B-chains at the core than at the periphery of the granule. Greater proportions of the long B-chains were present at the core than at the periphery of the granule.

Kinetic study of enzymatic hydrolysis of potato starch

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Óscar Fernando Castellanos Domínguez

2004-01-01

Full Text Available This article describes the kinetic study of potato starch enzymatic hydrolysis using soluble enzymes (Novo Nordisk. Different assays divided into four groups were used: reaction time (with which it was possible to reduce the 48-72 hour duration reported in the literature to 16 hours with comparable productivity levels; selecting the set of enzymes to be used (different types were evaluated - BAN and Termamyl as alfa-amylases during dextrinisation stage, and AMG, Promozyme and Fungamyl for sacarification reaction- identifying those presenting the best performance during hydrolysis.Reaction conditions were optimised for the process's two stages (destrinisation and sacarification. Enzyme dose, calcium cofactor concentration, pH, temperature and agitation speed were studied for the first stage. Enzyme ratio, pH and agitation speed were studied for sacarification; the latter parameter reported values having no antecedents in the literature (60 rpm and 30 rpm for first and second reactions, respectively. Michaelis Menten kinetics were calculated once conditions had been optimised, varying substrate from 10-50% P/V, obtaining km and Vmax kinetic parameters for each reaction. A kinetic model was found according to local working conditions which was able to explain potato starch conversion to glucose syrup, achieving 96 dextrose equivalents by the end of the reaction, being well within the maximum range reported in the literature (94-98.Laboratory equipment was constructed prior to carrying out assays which was able to reproduce and improve the conditions reported in the literature, making it a useful, reliable tool for use in assays returning good results.

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.

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

African Journals Online (AJOL)

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

Physiological covalent regulation of rat liver branched-chain alpha-ketoacid dehydrogenase

International Nuclear Information System (INIS)

Harris, R.A.; Powell, S.M.; Paxton, R.; Gillim, S.E.; Nagae, H.

1985-01-01

A radiochemical assay was developed for measuring branched-chain alpha-ketoacid dehydrogenase activity of Triton X-100 extracts of freeze-clamped rat liver. The proportion of active (dephosphorylated) enzyme was determined by measuring enzyme activities before and after activation of the complex with a broad-specificity phosphoprotein phosphatase. Hepatic branched-chain alpha-ketoacid dehydrogenase activity in normal male Wistar rats was 97% active but decreased to 33% active after 2 days on low-protein (8%) diet and to 13% active after 4 days on the same diet. Restricting protein intake of lean and obese female Zucker rats also caused inactivation of hepatic branched-chain alpha-ketoacid dehydrogenase complex. Essentially all of the enzyme was in the active state in rats maintained for 14 days on either 30 or 50% protein diets. This was also the case for rats maintained on a commercial chow diet (minimum 23% protein). However, maintaining rats on 20, 8, and 0% protein diets decreased the percentage of the active form of the enzyme to 58, 10, and 7% of the total, respectively. Fasting of chow-fed rats for 48 h had no effect on the activity state of hepatic branched-chain alpha-ketoacid dehydrogenase, i.e., 93% of the enzyme remained in the active state compared to 97% for chow-fed rats. However, hepatic enzyme of rats maintained on 8% protein diet was 10% active before starvation and 83% active after 2 days of starvation. Thus, dietary protein deficiency results in inactivation of hepatic branched-chain alpha-ketoacid dehydrogenase complex, presumably as a consequence of low hepatic levels of branched-chain alpha-ketoacids

Enzymatic digestibility and ethanol fermentability of AFEX-treated starch-rich lignocellulosics such as corn silage and whole corn plant

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Thelen Kurt D

2010-06-01

Full Text Available Abstract Background Corn grain is an important renewable source for bioethanol production in the USA. Corn ethanol is currently produced by steam liquefaction of starch-rich grains followed by enzymatic saccharification and fermentation. Corn stover (the non-grain parts of the plant is a potential feedstock to produce cellulosic ethanol in second-generation biorefineries. At present, corn grain is harvested by removing the grain from the living plant while leaving the stover behind on the field. Alternatively, whole corn plants can be harvested to cohydrolyze both starch and cellulose after a suitable thermochemical pretreatment to produce fermentable monomeric sugars. In this study, we used physiologically immature corn silage (CS and matured whole corn plants (WCP as feedstocks to produce ethanol using ammonia fiber expansion (AFEX pretreatment followed by enzymatic hydrolysis (at low enzyme loadings and cofermentation (for both glucose and xylose using a cellulase-amylase-based cocktail and a recombinant Saccharomyces cerevisiae 424A (LNH-ST strain, respectively. The effect on hydrolysis yields of AFEX pretreatment conditions and a starch/cellulose-degrading enzyme addition sequence for both substrates was also studied. Results AFEX-pretreated starch-rich substrates (for example, corn grain, soluble starch had a 1.5-3-fold higher enzymatic hydrolysis yield compared with the untreated substrates. Sequential addition of cellulases after hydrolysis of starch within WCP resulted in 15-20% higher hydrolysis yield compared with simultaneous addition of hydrolytic enzymes. AFEX-pretreated CS gave 70% glucan conversion after 72 h of hydrolysis for 6% glucan loading (at 8 mg total enzyme loading per gram glucan. Microbial inoculation of CS before ensilation yielded a 10-15% lower glucose hydrolysis yield for the pretreated substrate, due to loss in starch content. Ethanol fermentation of AFEX-treated (at 6% w/w glucan loading CS hydrolyzate (resulting

Enzymatic digestibility and ethanol fermentability of AFEX-treated starch-rich lignocellulosics such as corn silage and whole corn plant

Science.gov (United States)

2010-01-01

Background Corn grain is an important renewable source for bioethanol production in the USA. Corn ethanol is currently produced by steam liquefaction of starch-rich grains followed by enzymatic saccharification and fermentation. Corn stover (the non-grain parts of the plant) is a potential feedstock to produce cellulosic ethanol in second-generation biorefineries. At present, corn grain is harvested by removing the grain from the living plant while leaving the stover behind on the field. Alternatively, whole corn plants can be harvested to cohydrolyze both starch and cellulose after a suitable thermochemical pretreatment to produce fermentable monomeric sugars. In this study, we used physiologically immature corn silage (CS) and matured whole corn plants (WCP) as feedstocks to produce ethanol using ammonia fiber expansion (AFEX) pretreatment followed by enzymatic hydrolysis (at low enzyme loadings) and cofermentation (for both glucose and xylose) using a cellulase-amylase-based cocktail and a recombinant Saccharomyces cerevisiae 424A (LNH-ST) strain, respectively. The effect on hydrolysis yields of AFEX pretreatment conditions and a starch/cellulose-degrading enzyme addition sequence for both substrates was also studied. Results AFEX-pretreated starch-rich substrates (for example, corn grain, soluble starch) had a 1.5-3-fold higher enzymatic hydrolysis yield compared with the untreated substrates. Sequential addition of cellulases after hydrolysis of starch within WCP resulted in 15-20% higher hydrolysis yield compared with simultaneous addition of hydrolytic enzymes. AFEX-pretreated CS gave 70% glucan conversion after 72 h of hydrolysis for 6% glucan loading (at 8 mg total enzyme loading per gram glucan). Microbial inoculation of CS before ensilation yielded a 10-15% lower glucose hydrolysis yield for the pretreated substrate, due to loss in starch content. Ethanol fermentation of AFEX-treated (at 6% w/w glucan loading) CS hydrolyzate (resulting in 28 g/L ethanol

Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic Firmicutes Bacterium Ruminococcus bromii.

Science.gov (United States)

Ze, Xiaolei; Ben David, Yonit; Laverde-Gomez, Jenny A; Dassa, Bareket; Sheridan, Paul O; Duncan, Sylvia H; Louis, Petra; Henrissat, Bernard; Juge, Nathalie; Koropatkin, Nicole M; Bayer, Edward A; Flint, Harry J

2015-09-29

Ruminococcus bromii is a dominant member of the human gut microbiota that plays a key role in releasing energy from dietary starches that escape digestion by host enzymes via its exceptional activity against particulate "resistant" starches. Genomic analysis of R. bromii shows that it is highly specialized, with 15 of its 21 glycoside hydrolases belonging to one family (GH13). We found that amylase activity in R. bromii is expressed constitutively, with the activity seen during growth with fructose as an energy source being similar to that seen with starch as an energy source. Six GH13 amylases that carry signal peptides were detected by proteomic analysis in R. bromii cultures. Four of these enzymes are among 26 R. bromii proteins predicted to carry dockerin modules, with one, Amy4, also carrying a cohesin module. Since cohesin-dockerin interactions are known to mediate the formation of protein complexes in cellulolytic ruminococci, the binding interactions of four cohesins and 11 dockerins from R. bromii were investigated after overexpressing them as recombinant fusion proteins. Dockerins possessed by the enzymes Amy4 and Amy9 are predicted to bind a cohesin present in protein scaffoldin 2 (Sca2), which resembles the ScaE cell wall-anchoring protein of a cellulolytic relative, R. flavefaciens. Further complexes are predicted between the dockerin-carrying amylases Amy4, Amy9, Amy10, and Amy12 and two other cohesin-carrying proteins, while Amy4 has the ability to autoaggregate, as its dockerin can recognize its own cohesin. This organization of starch-degrading enzymes is unprecedented and provides the first example of cohesin-dockerin interactions being involved in an amylolytic system, which we refer to as an "amylosome." Fermentation of dietary nondigestible carbohydrates by the human colonic microbiota supplies much of the energy that supports microbial growth in the intestine. This activity has important consequences for health via modulation of

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.

Microscopic Analysis of Corn Fiber Using Corn Starch- and Cellulose-Specific Molecular Probes

Energy Technology Data Exchange (ETDEWEB)

Porter, S. E.; Donohoe, B. S.; Beery, K. E.; Xu, Q.; Ding, S.-Y.; Vinzant, T. B.; Abbas, C. A.; Himmel, M. E.

2007-09-01

Ethanol is the primary liquid transportation fuel produced from renewable feedstocks in the United States today. The majority of corn grain, the primary feedstock for ethanol production, has been historically processed in wet mills yielding products such as gluten feed, gluten meal, starch, and germ. Starch extracted from the grain is used to produce ethanol in saccharification and fermentation steps; however the extraction of starch is not 100% efficient. To better understand starch extraction during the wet milling process, we have developed fluorescent probes that can be used to visually localize starch and cellulose in samples using confocal microscopy. These probes are based on the binding specificities of two types of carbohydrate binding modules (CBMs), which are small substrate-specific protein domains derived from carbohydrate degrading enzymes. CBMs were fused, using molecular cloning techniques, to a green fluorescent protein (GFP) or to the red fluorescent protein DsRed (RFP). Using these engineered probes, we found that the binding of the starch-specific probe correlates with starch content in corn fiber samples. We also demonstrate that there is starch internally localized in the endosperm that may contribute to the high starch content in corn fiber. We also surprisingly found that the cellulose-specific probe did not bind to most corn fiber samples, but only to corn fiber that had been hydrolyzed using a thermochemical process that removes the residual starch and much of the hemicellulose. Our findings should be of interest to those working to increase the efficiency of the corn grain to ethanol process.

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

Effect of endogenous proteins and lipids on starch digestibility in rice flour.

Science.gov (United States)

Ye, Jiangping; Hu, Xiuting; Luo, Shunjing; McClements, David Julian; Liang, Lu; Liu, Chengmei

2018-04-01

The composition and structure of the food matrix can have a major impact on the digestion. The aim of this work was to investigate the effects of endogenous proteins and lipids on starch digestibility in rice flour, with an emphasis on establishing the underlying physicochemical mechanisms involved. Native long-grain indica rice flour and rice flour with the lipids and/or proteins removed were subjected to a simulated digestion in vitro. A significant increase in starch digestibility was observed after removal of proteins, lipids, or both. The starch digestibility of the rice flour without lipids was slightly lower than that without proteins, even though the proteins content was about 10-fold higher than the lipids content. Microstructural analysis suggested that the proteins and lipids were normally attached to the surfaces of the starch granules in the native rice flour, thus inhibiting their contact with digestive enzymes. Moreover, the proteins and lipids restricted the swelling of the starch granules, which may have decreased their digestion by reducing their surface areas. In addition, amylose-lipid complex was detected in the rice flour, which is also known to slow down starch digestion. These results have important implications for the design of foods with improved nutritional profiles. Copyright © 2018 Elsevier Ltd. All rights reserved.

Aroma interactions with starch

DEFF Research Database (Denmark)

Jørgensen, Anders Dysted

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

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

Science.gov (United States)

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

2015-05-05

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

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

Science.gov (United States)

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

2011-05-11

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

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

Science.gov (United States)

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

2014-11-04

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

Prebiotic properties of potato starch dextrins

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Renata Barczyńska

2015-09-01

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

Monitoring of soluble starch hydrolysis induced by α-amylase from Aspergillus oryzae using ultrasonic spectroscopy

Science.gov (United States)

Sierra, Carlos; Resa, Pablo; Buckin, Vitaly; Elvira, Luis

2012-05-01

The online monitoring of enzymatic starch hydrolysis is an important issue for several industrial sectors, mainly in the alimentary industry. Ultrasonic non-invasive methods based on the detection of wave velocity and amplitude changes can be used to study this enzymatic reaction. These wave propagating changes are result of physicalchemical modifications produced in the media by the starch hydrolysis. In this work the starch hydrolysis induced by the enzyme α-amylase from Aspergillus oryzae is studied. This biochemical reaction has been monitored using a high-resolution ultrasonic spectroscopy (HR-US) which is non-invasive and nondestructive. The measured time profiles o of ultrasonic velocity are explained in terms of the starch hydrolysis and the subsequent production of oligosaccharides as a consequence of the enzymatic action. The obtained results have been compared to a conventional off-line technique used in biochemistry, the iodine-starch reaction, a spectrophotometric method to quantify the amount of starch remaining in the medium. The combination of these two types of measurement provides more complete information about the biochemical processes occurred during hydrolysis.

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

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D'Hulst Christophe

2008-09-01

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

Biological studies on albino rats fed with Sorghum bicolor starch ...

African Journals Online (AJOL)

Partially purified amylase was extracted from the culture medium of Rhizopus sp. grown in potato dextrose broth for 48 h at room temperature by precipitation with 96.9% ethanol. The enzyme was used to hydrolyze sorghum starch. The hydrolyzed product was afterwards formulated into rat feed, which was fed to albino rats ...

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

Directory of Open Access Journals (Sweden)

Ingkasuwan Papapit

2012-08-01

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

Conversion of Cassava Starch to Produce Glucose and Fructose by Enzymatic Process Using Microwave Heating

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Sumardiono Siswo

2018-01-01

Full Text Available In this study, variation of glycosidase enzyme concentration and saccharification time on enzymatic hydrolysis using microwave have been investigated. Concentration and kinetic parameters rate of glucose and fructose were analyzed. Cassava starch was liquefied and gelatinized by microwave at 80°C. The gelatinized starch was saccharified at 60°C using (0.2;0.4;0.6;0.8;1% (w/v glycosidase enzyme for 24, 48 and 72 hours. The glucose which has been saccharified with 1% glycosidase enzyme for 72 hours gave highest conversion 66.23 %. The optimization process by multilevel reaction gave the highest conversion at enzyme concentrations 0.88 %and saccharification time 29 hours that 68.82%. The highest conversion of glucose was isomerized to fructose. The fructose which has been isomerized for 180 minutes gave highest conversion 20.05 %. The kinetics enzymatic reaction was approached and determined by Michaelis - Menten equation, Km and Vmax of reaction for glucose 22.94 g/L; 2.70 g/L hours and for fructose 3.39 g/L; 0.38 g/L. min respectively.

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

Science.gov (United States)

Slade, Louise; Levine, Harry

2018-04-13

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

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

Association mapping of starch chain length distribution and amylose content in pea (Pisum sativum L.) using carbohydrate metabolism candidate genes.

Science.gov (United States)

Carpenter, Margaret A; Shaw, Martin; Cooper, Rebecca D; Frew, Tonya J; Butler, Ruth C; Murray, Sarah R; Moya, Leire; Coyne, Clarice J; Timmerman-Vaughan, Gail M

2017-08-01

Although starch consists of large macromolecules composed of glucose units linked by α-1,4-glycosidic linkages with α-1,6-glycosidic branchpoints, variation in starch structural and functional properties is found both within and between species. Interest in starch genetics is based on the importance of starch in food and industrial processes, with the potential of genetics to provide novel starches. The starch metabolic pathway is complex but has been characterized in diverse plant species, including pea. To understand how allelic variation in the pea starch metabolic pathway affects starch structure and percent amylose, partial sequences of 25 candidate genes were characterized for polymorphisms using a panel of 92 diverse pea lines. Variation in the percent amylose composition of extracted seed starch and (amylopectin) chain length distribution, one measure of starch structure, were characterized for these lines. Association mapping was undertaken to identify polymorphisms associated with the variation in starch chain length distribution and percent amylose, using a mixed linear model that incorporated population structure and kinship. Associations were found for polymorphisms in seven candidate genes plus Mendel's r locus (which conditions the round versus wrinkled seed phenotype). The genes with associated polymorphisms are involved in the substrate supply, chain elongation and branching stages of the pea carbohydrate and starch metabolic pathways. The association of polymorphisms in carbohydrate and starch metabolic genes with variation in amylopectin chain length distribution and percent amylose may help to guide manipulation of pea seed starch structural and functional properties through plant breeding.

EFFECT OF DIETARY SUPPLEMENTATION OF NON-STARCH POLYSACCHARIDE DEGRADING ENZYMES ON GROWTH PERFORMANCE OF BROILER CHICKS

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M. A. Nadeem, M. I. Anjum, A. G. Khan and A. Azim

2005-10-01

Full Text Available An experiment was conducted to study the performance and carcass parameters of broilers chicks fed diets with and without supplementing non-starch polysaccharide degrading enzymes (NSPDE at the rate of 0.5 g/kg diet. A total of 300 day-old broiler chicks were randomly divided into 12 sets (replicates each comprising 25 chicks and three sets per treatment group, reared on deep litter from 1-42 days post-hatch. Group A was fed diets without NSPDE supplementation, while group B was fed diets supplemented with NSPDE (0.5 g/kg. Group C was fed diets containing 50 kcal/kg less metabolizable energy (ME without NSPDE and group D was fed diets having 50 kcal/kg less ME with NSPDE (0.5 g/kg supplementation. Feed and water were provided ad libitum. Feed intake and feed conversion ratio (FCR from 1-28 days and 1-42 days was significantly (p<0.05 improved in chicks fed NSPDE supplemented diets (groups B and D compared to non-supplemented diets (groups A and C. However, during 29-42 days of growing period enzymes supplementation did not influence feed intake and FCR. Body weight gain, dressing percentage and relative weights of heart, gizzard and shank at 42 days of age was found to be non-significantly different among all groups. However, liver weight reduced significantly (p<0.05 in NSPDE supplemented groups. The study suggested that NSPDE supplementation was beneficial in enhancing feed utilization during the starter phase, while its effects on weight gain, dressing percentage and weights of organs, except liver weight, were found to be non-significant.

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)

Overcoming hydrolysis of raw corn starch under industrial conditions with Bacillus licheniformis ATCC 9945a α-amylase.

Science.gov (United States)

Šokarda Slavić, Marinela; Pešić, Milja; Vujčić, Zoran; Božić, Nataša

2016-03-01

α-Amylase from Bacillus licheniformis ATCC 9945a (BliAmy) was proven to be very efficient in hydrolysis of granular starch below the temperature of gelatinization. By applying two-stage feeding strategy to achieve high-cell-density cultivation of Escherichia coli and extracellular production of BliAmy, total of 250.5 U/mL (i.e. 0.7 g/L) of enzyme was obtained. Thermostability of amylase was exploited to simplify purification. The hydrolysis of concentrated raw starch was optimized using response surface methodology. Regardless of raw starch concentration tested (20, 25, 30 %), BliAmy was very effective, achieving the final hydrolysis degree of 91 % for the hydrolysis of 30 % starch suspension after 24 h. The major A-type crystalline structure and amorphous domains of the starch granule were degraded at the same rates, while amylose-lipid complexes were not degraded. BliAmy presents interesting performances on highly concentrated solid starch and could be of value for starch-consuming industries while response surface methodology (RSM) could be efficiently applied for the optimization of the hydrolysis.

Concomitant production of detergent compatible enzymes by Bacillus flexus XJU-1.

Science.gov (United States)

Niyonzima, Francois N; More, Sunil S

2014-01-01

A soil screened Bacillus flexus XJU-1 was induced to simultaneously produce alkaline amylase, alkaline lipase and alkaline protease at their optimum levels on a common medium under submerged fermentation. The basal cultivation medium consisted of 0.5% casein, 0.5% starch and 0.5% cottonseed oil as an inducer for protease, amylase, and lipase, respectively. The casein also served as nitrogen source for all 3 enzymes. The starch was also found to act as carbon source additive for both lipase and protease. Maximum enzyme production occurred on fermentation medium with 1.5% casein, 1.5% soluble starch, 2% cottonseed oil, 2% inoculum size, initial pH of 11.0, incubation temperature of 37 °C and 1% soybean meal as a nitrogen source supplement. The analysis of time course study showed that 24 h was optimum incubation time for amylase whereas 48 h was the best time for both lipase and protease. After optimization, a 3.36-, 18.64-, and 27.33-fold increase in protease, amylase and lipase, respectively was recorded. The lipase was produced in higher amounts (37.72 U/mL) than amylase and protease about 1.27 and 5.85 times, respectively. As the 3 enzymes are used in detergent formulations, the bacterium can be commercially exploited to secrete the alkaline enzymes for use in detergent industry. This is the first report for concomitant production of 3 alkaline enzymes by a bacterium.

Thermo-Responsive Starch-g-(PAM-co-PNIPAM) : Controlled Synthesis and Effect of Molecular Components on Solution Rheology

NARCIS (Netherlands)

Fan, Yifei; Boulif, Nadia; Picchioni, Francesco

2018-01-01

A series of highly branched random copolymers of acrylamide (AM) and N-isopropylacrylamide (NIPAM) have been prepared from a waxy potato starch-based macroinitiator by aqueous Cu-0-mediated living radical polymerization (Cu-0-mediated LRP). The NIPAM intake in the copolymer was varied between 0% and

Optimization of Extrusion Process of Directly Expanded Snacks Based on Potato Starch in a Single Step for the Formation of Type IV Resistant Starch.

Science.gov (United States)

Calvo-López, Amira Daniela; Martínez-Bustos, Fernando

2017-09-01

Resistant starch type IV (RSIV) can be produced by chemical modifications (etherized or esterified) such as conversion, substitution, or cross-linking, which can prevent its digestion by blocking enzyme access and forming atypical linkages. In this research, the effects of barrel temperature (145.86-174.14 °C), the screw speed (42.93-57.07 Hz) and derivatization (esterification) in the formation of RSIV content of directly expanded snacks (second generation snacks) were studied. Potato starch was chemically modified by phosphorylation and succinylation, and expanded by using the extrusion cooking process. Snacks with phosphorylated starch showed expansion index from 2.57 to 3.23, bulk density from 306.19 to 479.00 kg/m 3 and RSIV from 43.27 to 55.81%. Snacks with succinylated starch had expansion index from 3.52 to 3.82, bulk density from 99.85 to 134.51 kg/m 3 and RSIV from 23.17 to 35.01%. The results found in this work showed that it is possible to manufacture extruded directly expanded snacks (second-generation snacks) such as a ready-to-eat (RTE) with good physicochemical properties and without substantial loss of extrusion functionality, which could bring a healthy benefit due to the presence of RSIV.

Enzyme Technology for Shipboard Waste Management

Science.gov (United States)

1976-12-01

sucrose to the sweeter invert sugar by the enzyme invertase is a well established process, as is the conversion of starch to glucose by the enzyme...aspects of our health and daily lives. Recent advances in fundamental and applied enzymology indicate that we have already started in that direction. At a...Chemtech, p. 677 (Nov 1973) 11 - Bungay, H. P., "Applied Enzymology ," Worthington, Biochemical Corp., Notes for an AIChE Lecture, Washington, D. C. (Dec

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

Application of enzymes in the textile industry: a review

OpenAIRE

Mojsov, Kiro

2011-01-01

The use of enzymes in textile industry is one of the most rapidly growing field in industrial enzymology. The enzymes used in the textile field are amylases, catalase, and laccase which are used to removing the starch, degrading excess hydrogen peroxide, bleaching textiles and degrading lignin. The use of enzymes in the textile chemical processing is rapidly gaining globally recognition because of their non-toxic and eco-friendly characteristics with the increasinly important requirements for...

Phase behaviour and in vitro hydrolysis of wheat starch in mixture with whey protein.

Science.gov (United States)

Yang, Natasha; Liu, Yingting; Ashton, John; Gorczyca, Elisabeth; Kasapis, Stefan

2013-04-15

Network formation of whey protein isolate (WPI) with increasing concentrations of native wheat starch (WS) has been examined. Small deformation dynamic oscillation in shear and modulated temperature differential scanning calorimetry enabled analysis of binary mixtures at the macro- and micromolecular level. Following heat induced gelation, textural hardness was measured by undertaking compression tests. Environmental scanning electron microscopy provided tangible information on network morphology of polymeric constituents. Experiments involving in vitro starch digestion also allowed for indirect assessment of phase topology in the binary mixture. The biochemical component of this work constitutes an attempt to utilise whey protein as a retardant to the enzymatic hydrolysis of starch in a model system with α-amylase enzyme. During heating, rheological profiles of binary mixtures exhibited dramatic increases in G' at temperatures more closely related to those observed for single whey protein rather than pure starch. Results from this multidisciplinary approach of analysis, utilising rheology, calorimetry and microscopy, argue for the occurrence of phase separation phenomena in the gelled systems. There is also evidence of whey protein forming the continuous phase with wheat starch being the discontinuous filler, an outcome that is explored in the in vitro study of the enzymatic hydrolysis of starch. Copyright © 2012. Published by Elsevier Ltd.

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

An enzyme complex increases in vitro dry matter digestibility of corn and wheat in pigs.

Science.gov (United States)

Park, Kyu Ree; Park, Chan Sol; Kim, Beob Gyun

2016-01-01

Two experiments were conducted to determine the effects of enzyme complex on in vitro dry matter (DM) digestibility for feed ingredients. The objective of experiment 1 was to screen feed ingredients that can be effective substrates for an enzyme complex, mainly consisted of β-pentosanase, β-glucanase and α-amylase, using in vitro digestibility methods. In experiment 1, the test ingredients were three grain sources (barley, corn and wheat) and six protein supplements (canola meal, copra expellers, cottonseed meal, distillers dried grains with solubles, palm kernel expellers and soybean meal). In vitro ileal and total tract digestibility (IVID and IVTTD, respectively) of DM for test ingredients were determined. In vitro digestibility methods consisted of two- or three-step procedure simulating in vivo digestion in the pig gastrointestinal tracts with or without enzyme complex. As the enzyme complex added, the IVID of DM for corn and wheat increased (p digestibility, corn grains were selected to determine the in vitro digestibility of the fractions (starch, germ, hull and gluten) that maximally respond to the enzyme complex in experiment 2. The IVID of DM for corn starch, germ and hull increased (p digestibility of corn and wheat, and the digestibility increments of corn are mainly attributed to the increased digestibility of corn starch.

Enzyme technology for precision functional food ingredient processes

DEFF Research Database (Denmark)

Meyer, Anne S.

2010-01-01

modification of potato starch processing residues. Such targeted enzyme-catalyzed reactions provide new invention opportunities for designing functional foods with significant health benefits. The provision of well-defined naturally structured compounds can, moreover, assist in obtaining the much...

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

NARCIS (Netherlands)

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

1994-01-01

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

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

Science.gov (United States)

Nguyen Vu, Hoang Phuong; Lumdubwong, Namfone

2016-12-10

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

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

Science.gov (United States)

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

2013-07-25

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

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

Directory of Open Access Journals (Sweden)

Luís Fernando Polesi

2018-01-01

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

Enzyme-Linked Immunosorbent Assay Specific for (1→6) Branched, (1→3)-β-d-Glucan Detection in Environmental Samples

OpenAIRE

Milton, Donald K.; Alwis, K. Udeni; Fisette, Leslie; Muilenberg, Michael

2001-01-01

(1→3)-β-d-Glucans have been recognized as a potential causative agent responsible for bioaerosol-induced respiratory symptoms observed in both indoor and occupational environments. A specific enzyme immunoassay was developed to quantify (1→6) branched, (1→3)-β-d-glucans in environmental samples. The assay was based on the use of a high-affinity receptor (galactosyl ceramide) specific for (1→3)-β-d-glucans as a capture reagent and a monoclonal antibody specific for fungal cell wall β-d-glucans...

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.

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

Degradation of the starch components amylopectin and amylose by barley α-amylase 1: Role of surface binding site 2

DEFF Research Database (Denmark)

Nielsen, Jonas Willum; Kramhøft, Birte; Bozonnet, Sophie

2012-01-01

Barley α-amylase isozyme 1 (AMY1, EC 3.2.1.1) contains two surface binding sites, SBS1 and SBS2, involved in the degradation of starch granules. The distinct role of SBS1 and SBS2 remains to be fully understood. Mutational analysis of Tyr-380 situated at SBS2 previously revealed that Tyr-380...... is required for binding of the amylose helix mimic, β-cyclodextrin. Also, mutant enzymes altered at position 380 displayed reduced binding to starch granules. Similarly, binding of wild type AMY1 to starch granules was suppressed in the presence of β-cyclodextrin. We investigated the role of SBS2 by comparing...... kinetic properties of the wild type AMY1 and the Y380A mutant enzyme in hydrolysis of amylopectin, amylose and β-limit dextrin, and the inhibition by β-cyclodextrin. Progress curves of the release of reducing ends revealed a bi-exponential hydrolysis of amylopectin and β-limit dextrin, whereas hydrolysis...

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.

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.

High resolution melting analysis for the detection of EMS induced mutations in wheat SbeIIa genes

Directory of Open Access Journals (Sweden)

Botticella Ermelinda

2011-11-01

Full Text Available Abstract Background Manipulation of the amylose-amylopectin ratio in cereal starch has been identified as a major target for the production of starches with novel functional properties. In wheat, silencing of starch branching enzyme genes by a transgenic approach reportedly caused an increase of amylose content up to 70% of total starch, exhibiting novel and interesting nutritional characteristics. In this work, the functionality of starch branching enzyme IIa (SBEIIa has been targeted in bread wheat by TILLING. An EMS-mutagenised wheat population has been screened using High Resolution Melting of PCR products to identify functional SNPs in the three homoeologous genes encoding the target enzyme in the hexaploid genome. Results This analysis resulted in the identification of 56, 14 and 53 new allelic variants respectively for SBEIIa-A, SBEIIa-B and SBEIIa-D. The effects of the mutations on protein structure and functionality were evaluated by a bioinformatic approach. Two putative null alleles containing non-sense or splice site mutations were identified for each of the three homoeologous SBEIIa genes; qRT-PCR analysis showed a significant decrease of their gene expression and resulted in increased amylose content. Pyramiding of different single null homoeologous allowed to isolate double null mutants showing an increase of amylose content up to 21% compared to the control. Conclusion TILLING has successfully been used to generate novel alleles for SBEIIa genes known to control amylose content in wheat. Single and double null SBEIIa genotypes have been found to show a significant increase in amylose content.

Structure and function of α-glucan debranching enzymes

DEFF Research Database (Denmark)

Møller, Marie Sofie; Henriksen, Anette; Svensson, Birte

2016-01-01

α-Glucan debranching enzymes hydrolyse α-1,6-linkages in starch/glycogen, thereby, playing a central role in energy metabolism in all living organisms. They belong to glycoside hydrolase families GH13 and GH57 and several of these enzymes are industrially important. Nine GH13 subfamilies include α......-glucan debranching enzymes; isoamylase and glycogen debranching enzymes (GH13_11); pullulanase type I/limit dextrinase (GH13_12–14); pullulan hydrolase (GH13_20); bifunctional glycogen debranching enzyme (GH13_25); oligo-1 and glucan-1,6-α-glucosidases (GH13_31); pullulanase type II (GH13_39); and α-amylase domains......_39 enzymes could represent a “missing link” between the strictly α-1,6-specific debranching enzymes and the enzymes with dual specificity and α-1,4-linkage preference....

Characterization of the Paenibacillus beijingensis DSM 24997 GtfD and its glucan polymer products representing a new glycoside hydrolase 70 subfamily of 4,6-α-glucanotransferase enzymes.

Directory of Open Access Journals (Sweden)

Joana Gangoiti

Full Text Available Previously we have reported that the Gram-negative bacterium Azotobacter chroococcum NCIMB 8003 uses the 4,6-α-glucanotransferase GtfD to convert maltodextrins and starch into a reuteran-like polymer consisting of (α1→4 glucan chains connected by alternating (α1→4/(α1→6 linkages and (α1→4,6 branching points. This enzyme constituted the single evidence for this reaction and product specificity in the GH70 family, mostly containing glucansucrases encoded by lactic acid bacteria (http://www.CAZy.org. In this work, 4 additional GtfD-like proteins were identified in taxonomically diverse plant-associated bacteria forming a new GH70 subfamily with intermediate characteristics between the evolutionary related GH13 and GH70 families. The GtfD enzyme encoded by Paenibacillus beijingensis DSM 24997 was characterized providing the first example of a reuteran-like polymer synthesizing 4,6-α-glucanotransferase in a Gram-positive bacterium. Whereas the A. chroococcum GtfD activity on amylose resulted in the synthesis of a high molecular polymer, in addition to maltose and other small oligosaccharides, two reuteran-like polymer distributions are produced by P. beijingensis GtfD: a high-molecular mass polymer and a low-molecular mass polymer with an average Mw of 27 MDa and 19 kDa, respectively. Compared to the A. chroooccum GtfD product, both P. beijingensis GtfD polymers contain longer linear (α1→4 sequences in their structure reflecting a preference for transfer of even longer glucan chains by this enzyme. Overall, this study provides new insights into the evolutionary history of GH70 enzymes, and enlarges the diversity of natural enzymes that can be applied for modification of the starch present in food into less and/or more slowly digestible carbohydrate structures.

Design of starch functionalized biodegradable P(MAA-co-MMA) as carrier matrix for l-asparaginase immobilization.

Science.gov (United States)

Ulu, Ahmet; Koytepe, Suleyman; Ates, Burhan

2016-11-20

We prepared biodegradable P(MAA-co-MMA)-starch composite as carrier matrix for the immobilization of l-asparaginase (l-ASNase), an important chemotherapeutic agent in acute lymphoblastic leukemia. Chemical characteristics and thermal stability of the prepared composites were determined by FT-IR, TGA, DTA and, DSC, respectively. Also, biodegradability measurements of P(MAA-co-MMA)-starch composites were carried out to examine the effects of degradation of the starch. Then, l-ASNase was immobilized on the P(MAA-co-MMA)-starch composites. The surface morphology of the composite before and after immobilization was characterized by SEM, EDX, and AFM. The properties of the immobilized l-ASNase were investigated and compared with the free enzyme. The immobilized l-ASNase had better showed thermal and pH stability, and remained stable after 30days of storage at 25°C. Thus, based on the findings of the present work, the P(MAA-co-MMA)-starch composite can be exploited as the biocompatible matrix used for l-ASNase immobilization for medical applications due to biocompatibility and biodegradability. Copyright © 2016 Elsevier Ltd. All rights reserved.

Starch granules size distribution in superior and inferior grains of wheat is related to enzyme activities and their gene expressions during grain filling

DEFF Research Database (Denmark)

Zhang, Chuanhui; Jiang, Dong; Liu, Fulai

2010-01-01

with the temporally change patterns of starch synthase activities and relative gene expression levels. For instance, activities of soluble and granule-bound starch synthases (designated SSS and GBSS) peaked at 20 and 24 DAF. Genes encoding isoforms of starch synthases expressed at different grain filling periods...

Characterization of an organic solvent-tolerant thermostable glucoamylase from a halophilic isolate, Halolactibacillus sp. SK71 and its application in raw starch hydrolysis for bioethanol production.

Science.gov (United States)

Yu, Hui-Ying; Li, Xin

2014-01-01

A halophilic bacterium Halolactibacillus sp. SK71 producing extracellular glucoamylase was isolated from saline soil of Yuncheng Salt Lake, China. Enzyme production was strongly influenced by the salinity of growth medium with maximum in the presence of 5% NaCl. The glucoamylase was purified to homogeneity with a molecular mass of 78.5 kDa. It showed broad substrate specificity and raw starch hydrolyzing activity. Analysis of hydrolysis products from soluble starch by thin-layer chromatography revealed that glucose was the sole end-product, indicating the enzyme was a true glucoamylase. Optimal enzyme activity was found to be at 70°C, pH 8.0, and 7.5% NaCl. In addition, it was highly active and stable over broad ranges of temperature (0-100°C), pH (7.0-12.0), and NaCl concentration (0-20%), showing excellent thermostable, alkali stable, and halotolerant properties. Furthermore, it displayed high stability in the presence of hydrophobic organic solvents. The purified glucoamylase was applied for raw corn starch hydrolysis and subsequent bioethanol production using Saccharomyces cerevisiae. The yield in terms of grams of ethanol produced per gram of sugar consumed was 0.365 g/g, with 71.6% of theoretical yield from raw corn starch. This study demonstrated the feasibility of using enzymes from halophiles for further application in bioenergy production. © 2014 American Institute of Chemical Engineers.

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

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.

Production of high-amylose maize lines using RNA interference in ...

African Journals Online (AJOL)

amylose maize lines with a low T-DNA copy number, demonstrating that RNAi is an efficient method for the production of high-amylose maize lines. Key words: Maize, high-amylose, RNA interference, starch branching enzyme gene sbe2a.

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

Science.gov (United States)

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

2014-05-10

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

Effects of dietary supplementation of Ulva pertusa and non-starch polysaccharide enzymes on gut microbiota of Siganus canaliculatus

Science.gov (United States)

Zhang, Xinxu; Wu, Huijuan; Li, Zhongzhen; Li, Yuanyou; Wang, Shuqi; Zhu, Dashi; Wen, Xiaobo; Li, Shengkang

2018-03-01

Fishes represent the highest diversity of vertebrates; however, our understanding of the compositions and functions of their gut microbiota is limited. In this study, we provided the first insight into the gut microbiota of the herbivorous fish Siganus canaliculatus by using three molecular ecology techniques based on the 16S rRNA genes (denaturing gradient gel electrophoresis, clone library construction, and highthroughput Illumina sequencing), and the Illumina sequencing technique is suggested here due to its higher overall coverage of the total 16S rRNA genes. A core gut microbiota of 29 bacterial groups, covering >99.9% of the total bacterial community, was found to be dominated by Proteobacteria and Firmicutes in fish fed three different diets with/without the supplementation of Ulva pertusa and non-starch polysaccharide (NSP) enzymes (cellulase, xylanase, and β-glucanase). Diverse potential NSP-degrading bacteria and probiotics (e.g., Ruminococcus, Clostridium and Lachnospiraceae) were detected in the intestine of the fish fed U. pertusa, suggesting that these microorganisms likely participated in the degradation of NSPs derived from U. pertusa. This study supports our previous conclusion that U. pertusa-based diets are suitable for the production of S. canaliculatus with lower costs without compromising quality.

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.

Branched nanotrees with immobilized acetylcholine esterase for nanobiosensor applications

DEFF Research Database (Denmark)

Risveden, Klas; Dick, Kimberly A; Bhand, Sunil

2010-01-01

A novel lab-on-a-chip nanotree enzyme reactor is demonstrated for the detection of acetylcholine. The reactors are intended for use in the RISFET (regional ion sensitive field effect transistor) nanosensor, and are constructed from gold-tipped branched nanorod structures grown on SiN(x)-covered w......A novel lab-on-a-chip nanotree enzyme reactor is demonstrated for the detection of acetylcholine. The reactors are intended for use in the RISFET (regional ion sensitive field effect transistor) nanosensor, and are constructed from gold-tipped branched nanorod structures grown on Si......N(x)-covered wafers. Two different reactors are shown: one with simple, one-dimensional nanorods and one with branched nanorod structures (nanotrees). Significantly higher enzymatic activity is found for the nanotree reactors than for the nanorod reactors, most likely due to the increased gold surface area...

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.

The Effect of Different Starch Liberation and Saccharification Methods on the Microbial Contaminations of Distillery Mashes, Fermentation Efficiency, and Spirits Quality

Directory of Open Access Journals (Sweden)

Katarzyna Pielech-Przybylska

2017-09-01

Full Text Available The aim of this study was to evaluate the influence of different starch liberation and saccharification methods on microbiological contamination of distillery mashes. Moreover, the effect of hop α-acid preparation for protection against microbial infections was assessed. The quality of agricultural distillates was also evaluated. When applying the pressureless liberation of starch (PLS and malt as a source of amylolytic enzymes, the lactic acid bacteria count in the mashes increased several times during fermentation. The mashes obtained using the pressure-thermal method and malt enzymes revealed a similar pattern. Samples prepared using cereal malt exhibited higher concentrations of lactic and acetic acids, as compared to mashes prepared using enzymes of microbial origin. The use of hop α-acids led to the reduction of bacterial contamination in all tested mashes. As a result, fermentation of both mashes prepared with microbial origin enzyme preparations and with barley malt resulted in satisfactory efficiency and distillates with low concentrations of aldehydes.

The Effect of Different Starch Liberation and Saccharification Methods on the Microbial Contaminations of Distillery Mashes, Fermentation Efficiency, and Spirits Quality.

Science.gov (United States)

Pielech-Przybylska, Katarzyna; Balcerek, Maria; Nowak, Agnieszka; Wojtczak, Maciej; Czyżowska, Agata; Dziekońska-Kubczak, Urszula; Patelski, Piotr

2017-09-30

The aim of this study was to evaluate the influence of different starch liberation and saccharification methods on microbiological contamination of distillery mashes. Moreover, the effect of hop α-acid preparation for protection against microbial infections was assessed. The quality of agricultural distillates was also evaluated. When applying the pressureless liberation of starch (PLS) and malt as a source of amylolytic enzymes, the lactic acid bacteria count in the mashes increased several times during fermentation. The mashes obtained using the pressure-thermal method and malt enzymes revealed a similar pattern. Samples prepared using cereal malt exhibited higher concentrations of lactic and acetic acids, as compared to mashes prepared using enzymes of microbial origin. The use of hop α-acids led to the reduction of bacterial contamination in all tested mashes. As a result, fermentation of both mashes prepared with microbial origin enzyme preparations and with barley malt resulted in satisfactory efficiency and distillates with low concentrations of aldehydes.

Determination of dietary starch in animal feeds and pet food by an enzymatic-colorimetric method: collaborative study.

Science.gov (United States)

Hall, Mary Beth

2015-01-01

Starch, glycogen, maltooligosaccharides, and other α-1,4- and α-1,6-linked glucose carbohydrates, exclusive of resistant starch, are collectively termed "dietary starch". This nutritionally important fraction is increasingly measured for use in diet formulation for animals as it can have positive or negative effects on animal performance and health by affecting energy supply, glycemic index, and formation of fermentation products by gut microbes. AOAC Method 920.40 that was used for measuring dietary starch in animal feeds was invalidated due to discontinued production of a required enzyme. As a replacement, an enzymatic-colorimetric starch assay developed in 1997 that had advantages in ease of sample handling and accuracy compared to other methods was considered. The assay was further modified to improve utilization of laboratory resources and reduce time required for the assay. The assay is quasi-empirical: glucose is the analyte detected, but its release is determined by run conditions and specification of enzymes. The modified assay was tested in an AOAC collaborative study to evaluate its accuracy and reliability for determination of dietary starch in animal feedstuffs and pet foods. In the assay, samples are incubated in screw cap tubes with thermostable α-amylase in pH 5.0 sodium acetate buffer for 1 h at 100°C with periodic mixing to gelatinize and partially hydrolyze α-glucan. Amyloglucosidase is added, and the reaction mixture is incubated at 50°C for 2 h and mixed once. After subsequent addition of water, mixing, clarification, and dilution as needed, free + enzymatically released glucose are measured. Values from a separate determination of free glucose are subtracted to give values for enzymatically released glucose. Dietary starch equals enzymatically released glucose multiplied by 162/180 (or 0.9) divided by the weight of the as received sample. Fifteen laboratories that represented feed company, regulatory, research, and commercial feed

Variation of Enzyme Activities and Metabolite Levels in 24 Arabidopsis Accessions Growing in Carbon-Limited Conditions1[W

Science.gov (United States)

Cross, Joanna M.; von Korff, Maria; Altmann, Thomas; Bartzetko, Linda; Sulpice, Ronan; Gibon, Yves; Palacios, Natalia; Stitt, Mark

2006-01-01

Our understanding of the interaction of carbon (C) metabolism with nitrogen (N) metabolism and growth is based mainly on studies of responses to environmental treatments, and studies of mutants and transformants. Here, we investigate which metabolic parameters vary and which parameters change in a coordinated manner in 24 genetically diverse Arabidopsis (Arabidopsis thaliana) accessions, grown in C-limited conditions. The accessions were grown in short days, moderate light, and high nitrate, and analyzed for rosette biomass, levels of structural components (protein, chlorophyll), total phenols and major metabolic intermediates (sugars, starch, nitrate, amino acids), and the activities of seven representative enzymes from central C and N metabolism. The largest variation was found for plant weight, reducing sugars, starch at the end of the night, and several enzyme activities. High levels of one sugar correlated with high levels of other sugars and starch, and a trend to increased amino acids, slightly lower nitrate, and higher protein. The activities of enzymes at the interface of C and N metabolism correlated with each other, but were unrelated to carbohydrates, amino acid levels, and total protein. Rosette weight was unrelated or showed a weak negative trend to sugar and amino acid contents at the end of the day in most of the accessions, and was negatively correlated with starch at the end of the night. Rosette weight was positively correlated with several enzyme activities. We propose that growth is not related to the absolute levels of starch, sugars, and amino acids; instead, it is related to flux, which is indicated by the enzymatic capacity to use these central resources. PMID:17085515

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.

The effect of rolled barley, sodium hydroxide-treated wheat or maize cob silage on digestive enzymes activity in the alimentary tract of dairy cows

DEFF Research Database (Denmark)

Moharrey, A.; Hymøller, Lone; Weisbjerg, Martin Riis

2017-01-01

In the present study digestive enzyme activities were studied in the rumen, intestine and faeces of dairy cows fed rations differing in starch source. Three total mixed rations were prepared for dairy cows with maize cob silage (MCS), sodium hydroxide-treated wheat (SHW) or rolled barley as starch...... DM (2.61 vs 2.91 and 3.15%) and a higher ash content (30.99 vs 29.24 and 24.31%) in the ruminal fluid without affecting enzyme activities. Positive correlation between lipolytic and amylolitic activities in ruminal fluid was stated, which supported the hypothesis that amylolytic bacteria provide...... energy for lipolytic bacteria. So, the enzymes activities in the different parts of the digestive tract were not affected by the different starch sources....

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.

Lactobacillus reuteri Strains Convert Starch and Maltodextrins into Homoexopolysaccharides Using an Extracellular and Cell-Associated 4,6-α-Glucanotransferase.

Science.gov (United States)

Bai, Yuxiang; Böger, Markus; van der Kaaij, Rachel Maria; Woortman, Albert Jan Jacob; Pijning, Tjaard; van Leeuwen, Sander Sebastiaan; van Bueren, Alicia Lammerts; Dijkhuizen, Lubbert

2016-04-13

Exopolysaccharides (EPS) of lactic acid bacteria (LAB) are of interest for food applications. LAB are well-known to produce α-glucan from sucrose by extracellular glucansucrases. Various Lactobacillus reuteri strains also possess 4,6-α-glucanotransferase (4,6-α-GTase) enzymes. Purified 4,6-α-GTases (e.g., GtfB) were shown to act on starches (hydrolysates), cleaving α1→4 linkages and synthesizing α1→6 linkages, yielding isomalto-/maltopolysaccharides (IMMP). Here we report that also L. reuteri cells with these extracellular, cell-associated 4,6-α-GTases synthesize EPS (α-glucan) from starches (hydrolysates). NMR, SEC, and enzymatic hydrolysis of EPS synthesized by L. reuteri 121 cells showed that these have similar linkage specificities but generally are much bigger in size than IMMP produced by the GtfB enzyme. Various IMMP-like EPS are efficiently used as growth substrates by probiotic Bifidobacterium strains that possess amylopullulanase activity. IMMP-like EPS thus have potential prebiotic activity and may contribute to the application of probiotic L. reuteri strains grown on maltodextrins or starches as synbiotics.

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

Science.gov (United States)

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

2016-06-01

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

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

Science.gov (United States)

Charoenrein, Sanguansri; Preechathammawong, Nutsuda

2012-10-01

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

Thermomechanical treatment of starch

NARCIS (Netherlands)

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

2006-01-01

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

Finding Biomass Degrading Enzymes Through an Activity-Correlated Quantitative Proteomics Platform (ACPP)

Science.gov (United States)

Ma, Hongyan; Delafield, Daniel G.; Wang, Zhe; You, Jianlan; Wu, Si

2017-04-01

The microbial secretome, known as a pool of biomass (i.e., plant-based materials) degrading enzymes, can be utilized to discover industrial enzyme candidates for biofuel production. Proteomics approaches have been applied to discover novel enzyme candidates through comparing protein expression profiles with enzyme activity of the whole secretome under different growth conditions. However, the activity measurement of each enzyme candidate is needed for confident "active" enzyme assignments, which remains to be elucidated. To address this challenge, we have developed an Activity-Correlated Quantitative Proteomics Platform (ACPP) that systematically correlates protein-level enzymatic activity patterns and protein elution profiles using a label-free quantitative proteomics approach. The ACPP optimized a high performance anion exchange separation for efficiently fractionating complex protein samples while preserving enzymatic activities. The detected enzymatic activity patterns in sequential fractions using microplate-based assays were cross-correlated with protein elution profiles using a customized pattern-matching algorithm with a correlation R-score. The ACPP has been successfully applied to the identification of two types of "active" biomass-degrading enzymes (i.e., starch hydrolysis enzymes and cellulose hydrolysis enzymes) from Aspergillus niger secretome in a multiplexed fashion. By determining protein elution profiles of 156 proteins in A. niger secretome, we confidently identified the 1,4-α-glucosidase as the major "active" starch hydrolysis enzyme (R = 0.96) and the endoglucanase as the major "active" cellulose hydrolysis enzyme (R = 0.97). The results demonstrated that the ACPP facilitated the discovery of bioactive enzymes from complex protein samples in a high-throughput, multiplexing, and untargeted fashion.

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.

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

Directory of Open Access Journals (Sweden)

Hongxia Miao

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

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

Science.gov (United States)

Liu, Weixin; Xu, Biyu; Jin, Zhiqiang

2014-01-01

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

Functional properties of irradiated starch

International Nuclear Information System (INIS)

Laouini, Wissal

2011-01-01

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

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

Science.gov (United States)

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

2015-10-01

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

Diurnal fluctuations in cotton leaf carbon export, carbohydrate content, and sucrose synthesizing enzymes.

Science.gov (United States)

Hendrix, D L; Huber, S C

1986-06-01

In fully expanded leaves of greenhouse-grown cotton (Gossypium hirsutum L., cv Coker 100) plants, carbon export, starch accumulation rate, and carbon exchange rate exhibited different behavior during the light period. Starch accumulation rates were relatively constant during the light period, whereas carbon export rate was greater in the afternoon than in the morning even though the carbon exchange rate peaked about noon. Sucrose levels increased throughout the light period and dropped sharply with the onset of darkness; hexose levels were relatively constant except for a slight peak in the early morning. Sucrose synthase, usually thought to be a degradative enzyme, was found in unusually high activities in cotton leaf. Both sucrose synthase and sucrose phosphate synthetase activities were found to fluctuate diurnally in cotton leaves but with different rhythms. Diurnal fluctuations in the rate of sucrose export were generally aligned with sucrose phosphate synthase activity during the light period but not with sucrose synthase activity; neither enzyme activity correlated with carbon export during the dark. Cotton leaf sucrose phosphate synthase activity was sufficient to account for the observed carbon export rates; there is no need to invoke sucrose synthase as a synthetic enzyme in mature cotton leaves. During the dark a significant correlation was found between starch degradation rate and leaf carbon export. These results indicate that carbon partitioning in cotton leaf is somewhat independent of the carbon exchange rate and that leaf carbon export rate may be linked to sucrose formation and content during the light period and to starch breakdown in the dark.

Starch Bioengineering in Barley

DEFF Research Database (Denmark)

Shaik, Shahnoor Sultana

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

Future cereal starch bioengineering

DEFF Research Database (Denmark)

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

2013-01-01

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

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

NARCIS (Netherlands)

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

1996-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1969-01-01

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

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

Branched nanotrees with immobilized acetylcholine esterase for nanobiosensor applications

Energy Technology Data Exchange (ETDEWEB)

Risveden, Klas; Bhand, Sunil; Danielsson, Bengt [Department of Pure and Applied Biochemistry, Center for Chemistry and Chemical Engineering, Lund University, PO Box 124, SE-22100 Lund (Sweden); Dick, Kimberly A; Samuelson, Lars [Solid State Physics, Lund University, Box 118, S-22100 Lund (Sweden); Rydberg, Patrik, E-mail: Kimberly.Dick@ftf.lth.se [Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen (Denmark)

2010-02-05

A novel lab-on-a-chip nanotree enzyme reactor is demonstrated for the detection of acetylcholine. The reactors are intended for use in the RISFET (regional ion sensitive field effect transistor) nanosensor, and are constructed from gold-tipped branched nanorod structures grown on SiN{sub x}-covered wafers. Two different reactors are shown: one with simple, one-dimensional nanorods and one with branched nanorod structures (nanotrees). Significantly higher enzymatic activity is found for the nanotree reactors than for the nanorod reactors, most likely due to the increased gold surface area and thereby higher enzyme binding capacity. A theoretical calculation is included to show how the enzyme kinetics and hence the sensitivity can be influenced and increased by the control of electrical fields in relation to the active sites of enzymes in an electronic biosensor. The possible effects of electrical fields employed in the RISFET on the function of acetylcholine esterase is investigated using quantum chemical methods, which show that the small electric field strengths used are unlikely to affect enzyme kinetics. Acetylcholine esterase activity is determined using choline oxidase and peroxidase by measuring the amount of choline formed using the chemiluminescent luminol reaction.

Starch Biosynthesis in Crop Plants

Directory of Open Access Journals (Sweden)

Ian J. Tetlow

2018-05-01

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

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

Science.gov (United States)

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

2015-01-01

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

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

Directory of Open Access Journals (Sweden)

Anne Mößeler

2015-01-01

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

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

Science.gov (United States)

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

2010-06-01

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

Inhibition by natural dietary substances of gastrointestinal absorption of starch and sucrose in rats and pigs: 1. Acute studies.

Science.gov (United States)

Preuss, Harry G; Echard, Bobby; Bagchi, Debasis; Stohs, Sidney

2007-08-06

Rapid gastrointestinal absorption of refined carbohydrates (CHO) is linked to perturbed glucose-insulin metabolism that is, in turn, associated with many chronic health disorders. We assessed the ability of various natural substances, commonly referred to as "CHO blockers," to influence starch and sucrose absorption in vivo in ninety-six rats and two pigs. These natural enzyme inhibitors of amylase/sucrase reportedly lessen breakdown of starches and sucrose in the gastrointestinal tract, limiting their absorption. To estimate absorption, groups of nine SD rats were gavaged with water or water plus rice starch and/or sucrose; and circulating glucose was measured at timed intervals thereafter. For each variation in the protocol a total of at least nine different rats were studied with an equal number of internal controls on three different occasions. The pigs rapidly drank CHO and inhibitors in their drinking water. In rats, glucose elevations above baseline over four hours following rice starch challenge as estimated by area-under-curve (AUC) were 40%, 27%, and 85% of their internal control after ingesting bean extract, hibiscus extract, and l-arabinose respectively in addition to the rice starch. The former two were significantly different from control. L-Arabinose virtually eliminated the rising circulating glucose levels after sucrose challenge, whereas hibiscus and bean extracts were associated with lesser decreases than l-arabinose that were still significantly lower than control. The glucose elevations above baseline over four hours in rats receiving sucrose (AUC) were 51%, 43% and 2% of control for bean extract, hibiscus extract, and L-arabinose, respectively. Evidence for dose-response of bean and hibiscus extracts is reported. Giving the natural substances minus CHO challenge caused no significant changes in circulating glucose concentrations, indicating no major effects on overall metabolism. A formula combining these natural products significantly

Regulation of adipose branched-chain amino acid catabolism enzyme expression and cross-adipose amino acid flux in human obesity

Science.gov (United States)

Lackey, Denise E.; Lynch, Christopher J.; Olson, Kristine C.; Mostaedi, Rouzbeh; Ali, Mohamed; Smith, William H.; Karpe, Fredrik; Humphreys, Sandy; Bedinger, Daniel H.; Dunn, Tamara N.; Thomas, Anthony P.; Oort, Pieter J.; Kieffer, Dorothy A.; Amin, Rajesh; Bettaieb, Ahmed; Haj, Fawaz G.; Permana, Paska; Anthony, Tracy G.

2013-01-01

Elevated blood branched-chain amino acids (BCAA) are often associated with insulin resistance and type 2 diabetes, which might result from a reduced cellular utilization and/or incomplete BCAA oxidation. White adipose tissue (WAT) has become appreciated as a potential player in whole body BCAA metabolism. We tested if expression of the mitochondrial BCAA oxidation checkpoint, branched-chain α-ketoacid dehydrogenase (BCKD) complex, is reduced in obese WAT and regulated by metabolic signals. WAT BCKD protein (E1α subunit) was significantly reduced by 35–50% in various obesity models (fa/fa rats, db/db mice, diet-induced obese mice), and BCKD component transcripts significantly lower in subcutaneous (SC) adipocytes from obese vs. lean Pima Indians. Treatment of 3T3-L1 adipocytes or mice with peroxisome proliferator-activated receptor-γ agonists increased WAT BCAA catabolism enzyme mRNAs, whereas the nonmetabolizable glucose analog 2-deoxy-d-glucose had the opposite effect. The results support the hypothesis that suboptimal insulin action and/or perturbed metabolic signals in WAT, as would be seen with insulin resistance/type 2 diabetes, could impair WAT BCAA utilization. However, cross-tissue flux studies comparing lean vs. insulin-sensitive or insulin-resistant obese subjects revealed an unexpected negligible uptake of BCAA from human abdominal SC WAT. This suggests that SC WAT may not be an important contributor to blood BCAA phenotypes associated with insulin resistance in the overnight-fasted state. mRNA abundances for BCAA catabolic enzymes were markedly reduced in omental (but not SC) WAT of obese persons with metabolic syndrome compared with weight-matched healthy obese subjects, raising the possibility that visceral WAT contributes to the BCAA metabolic phenotype of metabolically compromised individuals. PMID:23512805

Chemical Composition of Sea Buckthorn Leaves, Branches and Bark

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Gradt Ina

2017-06-01

Full Text Available Sea buckthorn leaves and branches presently create waste-/by-products of harvesting after pruning the plants. It is already known that sea buckthorn berries are important for their chemical composition and based on this occupy a wide field in nutrition. We raised the idea that sea buckthorn leaves, branches, and especially the bark, have also an extraordinary chemical composition like the berries. The aim of this study was to describe these by-products. For this purpose, detailed full analyses of corresponding samples from Russia (seven varieties and Germany (four varieties were performed. Especially the dry mass, fat content, proteins, carbohydrates, starch content, and crude fiber were investigated to obtain an overview. Minor components like total phenol content, metals, and water- and fat-soluble vitamins were also studied. All analytical parameters were based on an official collection of analysis methods (German ASU - amtliche Sammlung von Untersuchungsverfahren. The results of the full analysis of leaves and branches show some interesting aspects about the differences between male and female plants. Furthermore, we observed differences between Russian and German sea buckthorn varieties. Investigation of minor components showed that vitamins were present in very low amount (< 0.1 %.

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

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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.

The effect of alpha amylase enzyme on quality of sweet sorghum juice for chrystal sugar

Science.gov (United States)

Marwati, T.; Cahyaningrum, N.; Widodo, S.; Astiati, U. T.; Budiyanto, A.; Wahyudiono; Arif, A. B.; Richana, N.

2018-01-01

Sweet sorghum juice (Sorghum bicolor L. Moench) has characteristics similar to sugar cane juice and potentially used for sugar substitutes that can support food security. Nevertheless the sweet sorghum juicecontain starch which impede sorghum sugar crystallization. Therefore, research on the enzymatic process is needed to convert starch into reducing sugar. The experimental design used was the Factorial Randomized Design with the first factor was alpha amylase enzyme concentration (0, 20, 40, 60, 80, 100, 120 μL/100 mL) and second factor was incubation time (0, 30, 60, 90 minute) at temperature 100°C. The experiment was conducted on fresh sweet sorghum. The results showed that the addition of the alpha amylase enzyme increased the content of reducing sugar and decreased levels of starch. Elevating concentration of alpha amylase enzyme will increase the reducing sugar content in sweet sorghum juice. The optimum alpha amylase enzyme concentration to produce the highest total sugar was 80 μL/100 mL of sweet sorghum juice with the optimum incubation time was 90 minutes. The results of this study are expected to create a new sweetener for sugar substitution. From the economic prospective aspect, sorghum is a potential crop and can be relied upon to support the success of the food diversification program which further leads to the world food security

Simultaneous saccharification of inulin and starch using commercial glucoamylase and the subsequent bioconversion to high titer sorbitol and gluconic acid.

Science.gov (United States)

An, Kehong; Hu, Fengxian; Bao, Jie

2013-12-01

A new bioprocess for production of sorbitol and gluconic acid from two low-cost feedstocks, inulin and cassava starch, using a commercially available enzyme was proposed in this study. The commercial glucoamylase GA-L NEW from Genencor was found to demonstrate a high inulinase activity for hydrolysis of inulin into fructose and glucose. The glucoamylase was used to replace the expensive and not commercially available inulinase enzyme for simultaneous saccharification of inulin and starch into high titer glucose and fructose hydrolysate. The glucose and fructose in the hydrolysate were converted into sorbitol and gluconic acid using immobilized whole cells of the recombinant Zymomonas mobilis strain. The high gluconic acid concentration of 193 g/L and sorbitol concentration of 180 g/L with the overall yield of 97.3 % were obtained in the batch operations. The present study provided a practical production method of sorbitol and gluconic acid from low cost feedstocks and enzymes.

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

Science.gov (United States)

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

2017-07-19

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

Branched-Chain Aminotransferases Control TORC1 Signaling in Saccharomyces cerevisiae.

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Joanne M Kingsbury

2015-12-01

Full Text Available The conserved target of rapamycin complex 1 (TORC1 integrates nutrient signals to orchestrate cell growth and proliferation. Leucine availability is conveyed to control TORC1 activity via the leu-tRNA synthetase/EGOC-GTPase module in yeast and mammals, but the mechanisms sensing leucine remain only partially understood. We show here that both leucine and its α-ketoacid metabolite, α-ketoisocaproate, effectively activate the yeast TORC1 kinase via both EGOC GTPase-dependent and -independent mechanisms. Leucine and α-ketoisocaproate are interconverted by ubiquitous branched-chain aminotransferases (BCAT, which in yeast are represented by the mitochondrial and cytosolic enzymes Bat1 and Bat2, respectively. BCAT yeast mutants exhibit severely compromised TORC1 activity, which is partially restored by expression of Bat1 active site mutants, implicating both catalytic and structural roles of BCATs in TORC1 control. We find that Bat1 interacts with branched-chain amino acid metabolic enzymes and, in a leucine-dependent fashion, with the tricarboxylic acid (TCA-cycle enzyme aconitase. BCAT mutation perturbed TCA-cycle intermediate levels, consistent with a TCA-cycle block, and resulted in low ATP levels, activation of AMPK, and TORC1 inhibition. We propose the biosynthetic capacity of BCAT and its role in forming multicomplex metabolons connecting branched-chain amino acids and TCA-cycle metabolism governs TCA-cycle flux to activate TORC1 signaling. Because mammalian mitochondrial BCAT is known to form a supramolecular branched-chain α-keto acid dehydrogenase enzyme complex that links leucine metabolism to the TCA-cycle, these findings establish a precedent for understanding TORC1 signaling in mammals.

Evolution of the biosynthesis of the branched-chain amino acids

Science.gov (United States)

Keefe, Anthony D.; Lazcano, Antonio; Miller, Stanley L.

1995-01-01

The origins of the biosynthetic pathways for the branched-chain amino acids cannot be understood in terms of the backwards development of the present acetolactate pathway because it contains unstable intermediates. We propose that the first biosynthesis of the branched-chain amino acids was by the reductive carboxylation of short branched chain fatty acids giving keto acids which were then transaminated. Similar reaction sequences mediated by nonspecific enzymes would produce serine and threomine from the abundant prebiotic compounds glycolic and lactic acids. The aromatic amino acids may also have first been synthesized in this way, e.g. tryptophan from indole acetic acid. The next step would have been the biosynthesis of leucine from alpha-ketoisovalerc acid. The acetolactate pathway developed subsequently. The first version of the Krebs cycle, which was used for amino acid biosynthesis, would have been assembled by making use fo the reductive carboxylation and leucine biosynthesis enzymes, and completed with the development of a single new enzyme, succinate dehydrogenase. This evolutionary scheme suggests that there may be limitations to inferring the origins of metabolism by a simple back extrapolation of current pathways.

Effect of heat–moisture treatment on digestibility of different cultivars of sweet potato (Ipomea batatas (L.) Lam) starch

Science.gov (United States)

Senanayake, Suraji; Gunaratne, Anil; Ranaweera, K K D S; Bamunuarachchi, Arthur

2014-01-01

Different heat–moisture levels were applied to native starches from different cultivars of sweet potatoes available in Sri Lanka (Wariyapola red, Wariyapola white, Pallepola variety, Malaysian variety and CARI 273) to study the digestibility level. Samples were treated with 20, 25, and 30% moisture at 85°C and 120°C for 6 h and in vitro starch digestibility was tested with porcine pancreatin enzyme. A range of 19.3–23.5% digestibility was shown by the native starches with no significant difference (P digestibility level of the hydrothermally modified starches and the moisture content showed a positive impact on the digestibility. Heat–moisture treatment at 85°C brought an overall increase in digestibility and temperature beyond 85°C had a negative impact. No significant difference (P digestibility was observed with 20% and 25% moisture at 85°C and increased level were seen at 85°C and 30% moisture. PMID:25473497

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

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

EMF radiations (1800 MHz)-inhibited early seedling growth of maize (Zea mays) involves alterations in starch and sucrose metabolism.

Science.gov (United States)

Kumar, Arvind; Singh, Harminder Pal; Batish, Daizy R; Kaur, Shalinder; Kohli, Ravinder Kumar

2016-07-01

The present study investigated the impact of 1800-MHz electromagnetic field radiations (EMF-r), widely used in mobile communication, on the growth and activity of starch-, sucrose-, and phosphate-hydrolyzing enzymes in Zea mays seedlings. We exposed Z. mays to modulated continuous wave homogenous EMF-r at specific absorption rate (SAR) of 1.69±0.0 × 10(-1) W kg(-1) for ½, 1, 2, and 4 h. The analysis of seedlings after 7 days revealed that short-term exposure did not induce any significant change, while longer exposure of 4 h caused significant growth and biochemical alterations. There was a reduction in the root and coleoptile length with more pronounced effect on coleoptile growth (23 % reduction on 4-h exposure). The contents of photosynthetic pigments and total carbohydrates declined by 13 and 18 %, respectively, in 4-h exposure treatments compared to unexposed control. The activity of starch-hydrolyzing enzymes-α- and β-amylases-increased by ∼92 and 94 %, respectively, at an exposure duration of 4 h, over that in the control. In response to 4-h exposure treatment, the activity of sucrolytic enzymes-acid invertases and alkaline invertases-was increased by 88 and 266 %, whereas the specific activities of phosphohydrolytic enzymes (acid phosphatases and alkaline phosphatases) showed initial increase up to ≤2 h duration and then declined at >2 h exposure duration. The study concludes that EMF-r-inhibited seedling growth of Z. mays involves interference with starch and sucrose metabolism.

Chemical Modifications of Starch: Microwave Effect

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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.

Immobilised enzymes in biorenewable production

OpenAIRE

Franssen, M.C.R.; Steunenberg, P.; Scott, E.L.; Zuilhof, H.; Sanders, J.P.M.

2013-01-01

Oils, fats, carbohydrates, lignin, and amino acids are all important raw materials for the production of biorenewables. These compounds already play an important role in everyday life in the form of wood, fabrics, starch, paper and rubber. Enzymatic reactions do, in principle, allow the transformation of these raw materials into biorenewables under mild and sustainable conditions. There are a few examples of processes using immobilised enzymes that are already applied on an industrial scale, ...

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 ...

The Importance of Surface-Binding Site towards Starch-Adsorptivity Level in α-Amylase: A Review on Structural Point of View

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Umi Baroroh

2017-01-01

Full Text Available Starch is a polymeric carbohydrate composed of glucose. As a source of energy, starch can be degraded by various amylolytic enzymes, including α-amylase. In a large-scale industry, starch processing cost is still expensive due to the requirement of high temperature during the gelatinization step. Therefore, α-amylase with raw starch digesting ability could decrease the energy cost by avoiding the high gelatinization temperature. It is known that the carbohydrate-binding module (CBM and the surface-binding site (SBS of α-amylase could facilitate the substrate binding to the enzyme’s active site to enhance the starch digestion. These sites are a noncatalytic module, which could interact with a lengthy substrate such as insoluble starch. The major interaction between these sites and the substrate is the CH/pi-stacking interaction with the glucose ring. Several mutation studies on the Halothermothrix orenii, SusG Bacteroides thetaiotamicron, Barley, Aspergillus niger, and Saccharomycopsis fibuligera α-amylases have revealed that the stacking interaction through the aromatic residues at the SBS is essential to the starch adsorption. In this review, the SBS in various α-amylases is also presented. Therefore, based on the structural point of view, SBS is suggested as an essential site in α-amylase to increase its catalytic activity, especially towards the insoluble starch.

Purification, molecular cloning, and expression of 2-hydroxyphytanoyl- CoA lyase, a peroxisomal thiamine pyrophosphate-dependent enzyme that catalyzes the carbon-carbon bond cleavage during à-oxidation of 3- methyl-branched fatty acids

CERN Document Server

Foulon, V; Croes, K; Waelkens, E

1999-01-01

Purification, molecular cloning, and expression of 2-hydroxyphytanoyl- CoA lyase, a peroxisomal thiamine pyrophosphate-dependent enzyme that catalyzes the carbon-carbon bond cleavage during à-oxidation of 3- methyl-branched fatty acids

Continuous Production of Ethanol from Starch Using Glucoamylase and Yeast Co-Immobilized in Pectin Gel

Science.gov (United States)

Giordano, Raquel L. C.; Trovati, Joubert; Schmidell, Willibaldo

This work presents a continuous simultaneous saccharification and fermentation (SSF) process to produce ethanol from starch using glucoamylase and Saccharomyces cerevisiae co-immobilized in pectin gel. The enzyme was immobilized on macroporous silica, after silanization and activation of the support with glutaraldehyde. The silicaenzyme derivative was co-immobilized with yeast in pectin gel. This biocatalyst was used to produce ethanol from liquefied manioc root flour syrup, in three fixed bed reactors. The initial reactor yeast load was 0.05 g wet yeast/ml of reactor (0.1 g wet yeast/g gel), used in all SSF experiments. The enzyme concentration in the reactor was defined by running SSF batch assays, using different amount of silica-enzyme derivative, co-immobilized with yeast in pectin gel. The chosen reactor enzyme concentration, 3.77 U/ml, allowed fermentation to be the rate-limiting step in the batch experiment. In this condition, using initial substrate concentration of 166.0 g/1 of total reducing sugars (TRS), 1 ml gel/1 ml of medium, ethanol productivity of 8.3 g/l/h was achieved, for total conversion of starch to ethanol and 91% of the theoretical yield. In the continuous runs, feeding 163.0 g/1 of TRS and using the same enzyme and yeast concentrations used in the batch run, ethanol productivity was 5.9 g ethanol/1/h, with 97% of substrate conversion and 81% of the ethanol theoretical yield. Diffusion effects in the extra-biocatalyst film seemed to be reduced when operating at superficial velocities above 3.7 × 10-4 cm/s.

Bioethanol production by inherent enzymes from rye and wheat with addition of organic farming cheese whey

DEFF Research Database (Denmark)

Kádár, Zsófia; Christensen, Anne Deen; Thomsen, Mette Hedegaard

2011-01-01

. Throughout our studies, wheat and rye grain was used as raw material in bioethanol production with the purpose of producing in situ enzymes (during germination) for the hydrolysis of starch in the grains and compared with commercial amylase enzyme preparations. Whey permeate was incorporated into the grain...

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.

Investigating the Hydrolysis of Starch Using "a"-Amylase Contained in Dishwashing Detergent and Human Saliva

Science.gov (United States)

Munegumi, Toratane; Inutsuka, Masato; Hayafuji, Yukitaka

2016-01-01

Although saliva has commonly been used to teach about digestion by organisms, the phenomenon of digestion is actually caused by enzymes as catalytic substances. This activity explores the hydrolysis of starch by "a"-amylase in cleaning materials as well as a comparison with the similar reaction using human saliva. The fact that the…

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

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Juliane Mascarenhas Pereira

2016-01-01

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

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

Science.gov (United States)

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

2015-08-01

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

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

Determination of carbon isotope ratios in plant starch via selective enzymatic hydrolysis

International Nuclear Information System (INIS)

Schimmelmann, A.; DeNiro, M.J.

1983-01-01

A method for the determination of the carbon isotope ratios in bipolymers hydrolyzed by enzymatic action consists of separating the monomer by passage through a dialysis membrane and then combusting the monomer prior to isotopic analysis. The method is described for application to the analysis of starch, but it should find application for polymers than can be degraded quantitatively to monomers and/or oligomers using specific hydrolytic enzymes

Resistant starch: promise for improving human health.

Science.gov (United States)

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

2013-11-01

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

Plant-crafted starches for bioplastics production

DEFF Research Database (Denmark)

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

2016-01-01

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

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

Science.gov (United States)

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

2018-03-21

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

Kinetic modeling and exploratory numerical simulation of chloroplastic starch degradation

Directory of Open Access Journals (Sweden)

Nag Ambarish

2011-06-01

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

EVOLUTIONARY TRANSITIONS IN ENZYME ACTIVITY OF ANT FUNGUS GARDENS

DEFF Research Database (Denmark)

De Fine Licht, Henrik H; Schiøtt, Morten; Mueller, Ulrich G

2010-01-01

an association with a monophyletic clade of specialized symbionts. In conjunction with the transition to specialized symbionts, the ants advanced in colony size and social complexity. Here we provide a comparative study of the functional specialization in extracellular enzyme activities in fungus gardens across...... the attine phylogeny. We show that, relative to sister clades, gardens of higher-attine ants have enhanced activity of protein-digesting enzymes, whereas gardens of leaf-cutting ants also have increased activity of starch-digesting enzymes. However, the enzyme activities of lower-attine fungus gardens...... are targeted primarily towards partial degradation of plant cell walls, reflecting a plesiomorphic state of non-domesticated fungi. The enzyme profiles of the higher-attine and leaf-cutting gardens appear particularly suited to digest fresh plant materials and to access nutrients from live cells without major...

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

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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 .

Surface binding sites in amylase have distinct roles in recognition of starch structure motifs and degradation

DEFF Research Database (Denmark)

Cockburn, Darrell; Nielsen, Morten M.; Christiansen, Camilla

2015-01-01

degrading enzymes and critically important for their function. The affinity towards a variety of starch granules as well as soluble poly- and oligosaccharides of barley alpha-amylase 1 (AMY1) wild-type and mutants of two SBSs (SBS1 and SBS2) was investigated using Langmuir binding analysis, confocal laser...

Co-conjugation vis-à-vis individual conjugation of α-amylase and glucoamylase for hydrolysis of starch.

Science.gov (United States)

Jadhav, Swati B; Singhal, Rekha S

2013-10-15

Two enzymes, α-amylase and glucoamylase have been individually and co-conjugated to pectin by covalent binding. Both the enzyme systems showed better thermal and pH stability over the free enzyme system with the complete retention of original activities. Mixture of individually conjugated enzymes showed lower inactivation rate constant with longer half life than the co-conjugated enzyme system. Individually conjugated enzymes showed an increase of 56.48 kJ/mole and 38.22 kJ/mole in activation energy for denaturation than the free enzymes and co-conjugated enzymes, respectively. Km as well as Vmax of individually and co-conjugated enzymes was found to be higher than the free enzymes. SDS-polyacrylamide gel electrophoresis confirmed the formation of conjugate and co-conjugate as evident by increased molecular weight. Both the enzyme systems were used for starch hydrolysis where individually conjugated enzymes showed highest release of glucose at 60 °C and pH 5.0 as compared to free and co-conjugated enzyme. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

Structural biology of starch-degrading enzymes and their regulation

DEFF Research Database (Denmark)

Møller, Marie Sofie; Svensson, Birte

2016-01-01

disproportionating enzyme and a self-stabilised conformation of amylose accommodated in the active site of plant α-glucosidase. Important inhibitor complexes include a flavonol glycoside, montbretin A, binding at the active site of human pancreatic α-amylase and barley limit dextrinase inhibitor binding...

Acetylation and characterization of banana (Musa paradisiaca) starch.

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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.

Granular starch hydrolysis for fuel ethanol production

Science.gov (United States)

Wang, Ping

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

The role of Aspergillus flavus veA in the production of extracellular proteins during growth on starch substrates.

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Duran, Rocio M; Gregersen, Scott; Smith, Timothy D; Bhetariya, Preetida J; Cary, Jeffrey W; Harris-Coward, Pamela Y; Mattison, Christopher P; Grimm, Casey; Calvo, Ana M

2014-06-01

The aflatoxin-producer and opportunistic plant pathogenic, filamentous fungus Aspergillus flavus is responsible for the contamination of corn and other important agricultural commodities. In order to obtain nutrients from the host A. flavus produces a variety of extracellular hydrolytic enzymes. Interestingly, A. flavus amylase and protease activity are dependent on the global regulator veA, a gene known to regulate morphogenesis and secondary metabolism in numerous fungi. Analysis of starch degradation by fungal enzymes secreted into broths of starch- or corn kernel-based media showed a notable accumulation of glucose in samples of the A. flavus control strain while the deletion veA sample accumulated high levels of maltose and maltotriose and only a small amount of glucose. Furthermore, SDS-PAGE and proteomics analysis of culture broths from starch- or corn kernel-based media demonstrated differential production of a number of proteins that included a reduction in the amount of a glucoamylase protein in the veA mutant compared to the control strain, while an alpha-amylase was produced in greater quantities in the veA mutant. Quantitative real-time PCR and western blot analyses using anti-glucoamylase or alpha-amylase antisera supported the proteomics results. Additionally, an overall reduction in protease activity was observed in the veA mutant including production of the alkaline protease, oryzin, compared to the control strain. These findings contribute to our knowledge of mechanisms controlling production of hydrolases and other extracellular proteins during growth of A. flavus on natural starch-based substrates.

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 ...

Influence of non starch polysaccharide-degrading enzymes on the ...

African Journals Online (AJOL)

enzymes on the performance, meat yield, water intake, litter moisture and jejunal digesta viscosity of chicks fed wheat/barley based diet. A total of 195 1-d-old male broiler chicks (Ross 308) were allocated to 5 treatment groups, with 3 replicates per ...

A phylogenetic analysis of normal modes evolution in enzymes and its relationship to enzyme function.

Science.gov (United States)

Lai, Jason; Jin, Jing; Kubelka, Jan; Liberles, David A

2012-09-21

Since the dynamic nature of protein structures is essential for enzymatic function, it is expected that functional evolution can be inferred from the changes in protein dynamics. However, dynamics can also diverge neutrally with sequence substitution between enzymes without changes of function. In this study, a phylogenetic approach is implemented to explore the relationship between enzyme dynamics and function through evolutionary history. Protein dynamics are described by normal mode analysis based on a simplified harmonic potential force field applied to the reduced C(α) representation of the protein structure while enzymatic function is described by Enzyme Commission numbers. Similarity of the binding pocket dynamics at each branch of the protein family's phylogeny was analyzed in two ways: (1) explicitly by quantifying the normal mode overlap calculated for the reconstructed ancestral proteins at each end and (2) implicitly using a diffusion model to obtain the reconstructed lineage-specific changes in the normal modes. Both explicit and implicit ancestral reconstruction identified generally faster rates of change in dynamics compared with the expected change from neutral evolution at the branches of potential functional divergences for the α-amylase, D-isomer-specific 2-hydroxyacid dehydrogenase, and copper-containing amine oxidase protein families. Normal mode analysis added additional information over just comparing the RMSD of static structures. However, the branch-specific changes were not statistically significant compared to background function-independent neutral rates of change of dynamic properties and blind application of the analysis would not enable prediction of changes in enzyme specificity. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

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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

Acha ( Digitaria exilis ) Malt as a Source of Enzyme for Bio-Ethanol ...

African Journals Online (AJOL)

... exilis ) Malt as a Source of Enzyme for Bio-Ethanol Production from Starchy Materials. ... Incubating a mixture of raw starch and acha malt at 50oC for 30 minutes ... has great potential application in brewery and ethanol production industries.

POTENTIAL USE OF AN EXTRACELLULAR ENZYME OF a-AMYLASE FROM INDIGENOUS INDONESIAN MESOPHILIC BACTERIA

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Puji Lestari

2013-04-01

Full Text Available Amylase enzyme has a great significance for industrial usages in  Indonesia. However, this enzyme is still imported. The use of bacteria in biotechnological process of industrial products such as enzyme production has stimulated the exploration of extracellular amylase producing  bacteria. This study aimed to identify and analyze the potential use of amylolytic bacterial enzymes for hydrolyzing cassava starch. Two bacterial isolates, i.e. MII-10 and DKW-8 originated from Indonesia soil were identified based on their morphological, physiological and biochemical properties according to the standard protocol. The isolates were then  cultivated on fermentation medium and their growth pattern and  enzymatic assays were observed. The acetone-precipitated crude enzyme harvested based on predetermined cultivation time was used for  enzymatic hydrolysis product characterization on cassava starch using thin layer chromatography (TLC. The results showed that the mesophilicbacteria isolates (MII-10 and DKW-8 were belonged to Bacillus licheniformis. The maximum bacterial cell growth and enzyme activity were reached at 48 hours after incubation. The MII-10 isolate was found more stable than DKW-8 in producing amylase enzyme. Amylase produced by the MII-10 and DKW- 8 isolates was identified to be an endo-a-amylase as confirmed by oligosaccharides and dextrin of the random hydrolysisproducts. Relatively high dextrose equivalence (DE value of a-amylase of MII-10 (DE of 9.96 suggests that the enzyme is prospective for  saccharification of starchy material in glucose syrup industry.

Physiochemical properties and kinetics of glucoamylase produced from deoxy-d-glucose resistant mutant of Aspergillus niger for soluble starch hydrolysis.

Science.gov (United States)

Riaz, Muhammad; Rashid, Muhammad Hamid; Sawyer, Lindsay; Akhtar, Saeed; Javed, Muhammad Rizwan; Nadeem, Habibullah; Wear, Martin

2012-01-01

Glucoamylases (GAs) from a wild and a deoxy-d-glucose-resistant mutant of a locally isolated Aspergillus niger were purified to apparent homogeneity. The subunit molecular mass estimated by SDS-PAGE was 93 kDa for both strains, while the molecular masses determined by MALDI-TOF for wild and mutant GAs were 72.876 and 72.063 kDa, respectively. The monomeric nature of the enzymes was confirmed through activity staining. Significant improvement was observed in the kinetic properties of the mutant GA relative to the wild type enzyme. Kinetic constants of starch hydrolysis for A. niger parent and mutant GAs calculated on the basis of molecular masses determined through MALDI-TOF were as follows: k cat = 343 and 727 s -1 , K m = 0.25 and 0.16 mg mL -1 , k cat / K m (specificity constant) = 1374 and 4510 mg mL -1 s -1 , respectively. Thermodynamic parameters for soluble starch hydrolysis also suggested that mutant GA was more efficient compared to the parent enzyme.

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

Enzyme clustering accelerates processing of intermediates through metabolic channeling

Science.gov (United States)

Castellana, Michele; Wilson, Maxwell Z.; Xu, Yifan; Joshi, Preeti; Cristea, Ileana M.; Rabinowitz, Joshua D.; Gitai, Zemer; Wingreen, Ned S.

2015-01-01

We present a quantitative model to demonstrate that coclustering multiple enzymes into compact agglomerates accelerates the processing of intermediates, yielding the same efficiency benefits as direct channeling, a well-known mechanism in which enzymes are funneled between enzyme active sites through a physical tunnel. The model predicts the separation and size of coclusters that maximize metabolic efficiency, and this prediction is in agreement with previously reported spacings between coclusters in mammalian cells. For direct validation, we study a metabolic branch point in Escherichia coli and experimentally confirm the model prediction that enzyme agglomerates can accelerate the processing of a shared intermediate by one branch, and thus regulate steady-state flux division. Our studies establish a quantitative framework to understand coclustering-mediated metabolic channeling and its application to both efficiency improvement and metabolic regulation. PMID:25262299

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

Catalytic Properties of Amylolytic Enzymes Produced by Gongronella butleri Using Agroindustrial Residues on Solid-State Fermentation

Science.gov (United States)

Cavalheiro, Gabriéla Finoto; Sanguine, Isadora Stranieri; Santos, Flávia Regina da Silva; da Costa, Ana Carolina; Fernandes, Matheus; da Paz, Marcelo Fossa; Fonseca, Gustavo Graciano

2017-01-01

Amylases catalyze the hydrolysis of starch, a vegetable polysaccharide abundant in nature. These enzymes can be utilized in the production of syrups, alcohol, detergent, pharmaceutical products, and animal feed formulations. The aim of this study was to optimize the production of amylases by the filamentous fungus Gongronella butleri by solid-state fermentation and to evaluate the catalytic properties of the obtained enzymatic extract. The highest amylase production, 63.25 U g−1 (or 6.32 U mL−1), was obtained by culturing the fungus in wheat bran with 55% of initial moisture, cultivated for 96 h at 25°C. The enzyme presented optimum activity at pH 5.0 and 55°C. The amylase produced was stable in a wide pH range (3.5–9.5) and maintained its catalytic activity for 1 h at 40°C. Furthermore, the enzymatic extract hydrolyzed starches from different vegetable sources, presenting predominant dextrinizing activity for all substrates evaluated. However, the presence of glucose was observed in a higher concentration during hydrolysis of corn starch, indicating the synergistic action of endo- and exoamylases, which enables the application of this enzymatic extract to produce syrups from different starch sources. PMID:29376074

Catalytic Properties of Amylolytic Enzymes Produced by Gongronella butleri Using Agroindustrial Residues on Solid-State Fermentation

Directory of Open Access Journals (Sweden)

Gabriéla Finoto Cavalheiro

2017-01-01

Full Text Available Amylases catalyze the hydrolysis of starch, a vegetable polysaccharide abundant in nature. These enzymes can be utilized in the production of syrups, alcohol, detergent, pharmaceutical products, and animal feed formulations. The aim of this study was to optimize the production of amylases by the filamentous fungus Gongronella butleri by solid-state fermentation and to evaluate the catalytic properties of the obtained enzymatic extract. The highest amylase production, 63.25 U g−1 (or 6.32 U mL−1, was obtained by culturing the fungus in wheat bran with 55% of initial moisture, cultivated for 96 h at 25°C. The enzyme presented optimum activity at pH 5.0 and 55°C. The amylase produced was stable in a wide pH range (3.5–9.5 and maintained its catalytic activity for 1 h at 40°C. Furthermore, the enzymatic extract hydrolyzed starches from different vegetable sources, presenting predominant dextrinizing activity for all substrates evaluated. However, the presence of glucose was observed in a higher concentration during hydrolysis of corn starch, indicating the synergistic action of endo- and exoamylases, which enables the application of this enzymatic extract to produce syrups from different starch sources.

Preparation, characterization and utilization of starch nanoparticles.

Science.gov (United States)

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

2015-02-01

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

Cassava starch in the Brazilian food industry

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Ivo Mottin Demiate

2011-06-01

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

Starch digestibility and predicted glycemic index in the bread fortified with pomelo (Citrus maxima) fruit segments.

Science.gov (United States)

Reshmi, S K; Sudha, M L; Shashirekha, M N

2017-12-15

The aim of this study was to evaluate the starch digestibility and predicted glycemic index in breads incorporated with pomelo fruit (Citrus maxima) segments. Volume of the white and brown breads supplemented with pomelo fresh segments increased, while the crumb firmness decreased. Bread with 20% fresh and 5% dry pomelo segments were sensorily acceptable. Bioactive components such as phenolics, flavonoids, naringin and carotenoids were retained to a greater extent in bread containing dry pomelo segments. The pomelo incorporated bread had higher levels of resistant starch fractions (3.87-10.96%) with low predicted glycemic index (62.97-53.13%), despite their higher total starch (69.87-75.47%) content compared to control bread. Thus pomelo segments in the product formulations lowered the glycemic index probably by inhibiting carbohydrate hydrolyzing enzyme activity which could be attributed to naringin. Hence fortified bread prepared from pomelo fruit segment is recommended to gain nutritional value and to decrease the risk of diabetes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of a novel debranching enzyme from Nostoc punctiforme possessing a high specificity for long branched chains

International Nuclear Information System (INIS)

Choi, Ji-Hye; Lee, Heeseob; Kim, Young-Wan; Park, Jong-Tae; Woo, Eui-Jeon; Kim, Myo-Jeong; Lee, Byong-Hoon; Park, Kwan-Hwa

2009-01-01

A novel debranching enzyme from Nostoc punctiforme PCC73102 (NPDE) exhibits hydrolysis activity toward both α-(1,6)- and α-(1,4)-glucosidic linkages. The action patterns of NPDE revealed that branched chains are released first, and the resulting maltooligosaccharides are then hydrolyzed. Analysis of the reaction with maltooligosaccharide substrates labeled with 14 C-glucose at the reducing end shows that NPDE specifically liberates glucose from the reducing end. Kinetic analyses showed that the hydrolytic activity of NPDE is greatly affected by the length of the substrate. The catalytic efficiency of NPDE increased considerably upon using substrates that can occupy at least eight glycone subsites such as maltononaose and maltooctaosyl-α-(1,6)-β-cyclodextrin. These results imply that NPDE has a unique subsite structure consisting of -8 to +1 subsites. Given its unique subsite structure, side chains shorter than maltooctaose in amylopectin were resistant to hydrolysis by NPDE, and the population of longer side chains was reduced.

Physicochemical Properties of Gamma-Irradiated Corn Starch

International Nuclear Information System (INIS)

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

2006-01-01

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

Plant-crafted starches for bioplastics production.

Science.gov (United States)

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

2016-11-05

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

Green starch conversions : Studies on starch acetylation in densified CO2

NARCIS (Netherlands)

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

2010-01-01

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

Starch Characteristics Linked to Gluten-Free Products