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Properties of Starch and Modified Starches
Published in Jean-Luc Wertz, Bénédicte Goffin, Starch in the Bioeconomy, 2020
Jean-Luc Wertz, Bénédicte Goffin
Common enzymes used in starch processing include α-amylase, β-amylase, glucoamylase, pullulanase, and isoamylase.41 During the hydrolysis process, enzymes attack α-(1→4) and/or α-(1→6) linkages, depolymerizing starch into glucose, maltose, and/or oligosaccharides. Starch is capable of forming inclusion complexes with hydrophobic molecules; however, native starch displays limited capability because of its tendency to retrograde and the highly branched structure of amylopectin. Efforts to enhance starch complexing ability have been carried out through chemical and enzymatic modifications. Enzymatic modification of starch has been used to increase the linear starch content, thus increasing its complexing ability.
Produced by Recombinant Bacteria
Published in Yoshikatsu Murooka, Tadayuki Imanaka, Recombinant Microbes for Industrial and Agricultural Applications, 2020
Debranching enzymes hydrolyze the α-l,6-glucosidic linkages of starch and are present in higher plants and microorganisms. Isoamylase (EC 3.2.1.68; glycogen 6-glucanohydrolase), pullulanase (EC 3.2.1.41; pullulan 6-glucanohydrolase), and amylo-1,6-glucosidase (EC 3.2.1.33) belong to this group of enzymes. They are useful for structural analysis of starch, glycogen, pullulan, and other saccharides. Isoamylase and pullulanase are used industrially to produce glucose or maltose from starch in combination with glucoamylase or β-amylase, respectively.
Pullulan-Degrading Enzymes and Their Biochemical Features
Published in Shakeel Ahmed, Aisverya Soundararajan, Pullulan, 2020
Earlier starch hydrolysis was carried out by traditional acid hydrolysis method. Since the 1960s, almost all processes to convert starch to glucose have changed to the enzymatic hydrolysis method. Today, much of the starch hydrolysates available in the market are enzyme-converted products of higher dextrose equivalent (DE) value [33]. DE is a measure of reducing sugar on a dry basis, pure dextrose (glucose) being DE 100 and starch being close to DE 0. The enzymatic conversion of starch into glucose, maltose, and fructose for use as food sweeteners is a rapidly growing area in industrial enzyme usage. The primary application of pullulanase is in starch saccharification, and the most important industrial use of pullulanase is in the production of high-glucose (30% to 50% glucose; 30% to 40% maltose) or high-maltose (30% to 50% maltose; 6% to 10% glucose) syrups [34, 35]. In the saccharification process, pullulanase is normally used in combination with glucoamylase or β-amylase [14, 35]. In the hydrolysis of starch, pullulanase and isoamylase play important roles in living cells too because they are the only enzymes that selectively hydrolyze α-1,6 linkages in glucans. Both enzymes are endo acting and produce α-1,4 glucan chains or malto-oligosaccharides. Pullulanase hydrolyzes pullulan and amylopectin completely or nearly completely; however, it can hydrolyze glycogen only to a limited extent. On the other hand, isoamylase hydrolyzes amylopectin and glycogen completely; however, it cannot act on pullulan. Isoamylase is used as a powerful tool in the analysis of the fine structure of amylopectin, whereas pullulanase, in combination with β-amylase, is widely used in the starch saccharification industry to produce maltose. Enzymatic properties of isoamylase from Pseudomonas amyloderamosa have been extensively studied, and an enzyme preparation from Pseudomonas sp. is commercially available. Pullulanase preparations from Klebsiella sp., Bacillus brevis, B. licheniformis, and Bacillus acidopulluliticus are available from several enzyme manufacturers. The enzyme prepared from B. acidopulluliticus is thermostable and thus widely used in the starch industry.
Bio characterization of purified isoamylase from Rhizopus oryzae
Published in Preparative Biochemistry & Biotechnology, 2020
Banita Ghosh, Dibyajit Lahiri, Moupriya Nag, Sudipta Dash, Rina Rani Ray
Isoamylases play an important role in determining the formation of food ingredients from various sources such as trehalose, maltitol, resistant starch and cyclodextrin. Carbohydrate sources like glucose and maltose is widely being used as sweetener in food and pharmaceutical and food industry whereas maltitol is used as non-calorigenic sugar substituent. Isoamylase plays an important role in the mechanism of saccharification that helps in isolating polypeptide having isoamylolytic activity on substances which are amylaceous and having high amount of maltose content thus increases its importance in industry.[6]