Dextrin
Dextrins are a group of low-molecular-weight carbohydrates produced by the hydrolysis of starch. Dextrins are mixtures of linear ?-(1,4)-linked D-glucose polymers starting with an ?-(1,6) bond. Because branched amylopectin and glycogen also contain ?-(1,6) bonds, which ?-amylase cannot hydrolyze in humans, the digest resulting from this action contains a mixture of dextrins. They have the same general formula as carbohydrates but are of shorter chain length. Industrial production is, in general, performed by acidic hydrolysis of potato starch. Dextrins are water-soluble, white to slightly yellow solids that are optically active. Under analysis, dextrins can be detected with iodine solution, giving a red coloration.
The cyclical dextrins are known as cyclodextrins. They are formed by enzymatic degradation of starch by certain bacteria, for example, Bacillus macerans. Cyclodextrins have toroidal structures formed by 6-8 glucose residues.
Dextrins find widespread use in industry, due to their non-toxicity and their low price. They are used as water-soluble glues, as thickening agents in food processing, and as binding agent in pharmaceuticals. In pyrotechnics, they are added to fire formulas, allowing them to solidify as pellets or “stars.” Cyclodextrins find additional use in analytical chemistry as a matrix for the separation of hydrophobic substances, and as excipients in pharmaceutical formulations. Not all forms of dextrin are digestible, and indigestible dextrin is sometimes used in fiber supplements.
Maltodextrin is a polysaccharide that is used as a food additive. It is produced from starch and is usually found as a creamy-white hygroscopic powder. Maltodextrin is easily digestible, being absorbed as rapidly as glucose, and might either be moderately sweet or might have hardly any flavor at all. The CAS registry number of maltodextrin is 9050-36-6.
Maltodextrin can be derived from any starch. In the US, this starch is usually rice, corn or potato; elsewhere, such as in Europe, it is commonly wheat. This is important for coeliacs, since the wheat-derived maltodextrin can contain traces of gluten. There have been recent reports of coeliac reaction to maltodextrin in the United States. This might be a consequence of the shift of corn to ethanol production and its replacement with wheat in the formulation. The fast food chain, Wendy’s, footnotes maltodextrin in its list of gluten-free foods [1], which may be a sign of their receiving reports of this.
Foods containing maltodextrin may contain traces of amino acids, including glutamic acid as a manufacturing by-product. The amino acid traces would be too small to have any dietary significance.
Maltodextrin may contain monosodium glutamate or create MSG during processing.[1]
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In enzymology, a dextrin dextranase (EC 2.4.1.2) is an enzyme that catalyzes the chemical reaction
(1,4-alpha-D-glucosyl)n + (1,6-alpha-D-glucosyl)m (1,4-alpha-D-glucosyl)n-1 + (1,6-alpha-D-glucosyl)m+1
Thus, the two substrates of this enzyme are (1,4-alpha-D-glucosyl)n and (1,6-alpha-D-glucosyl)m, whereas its two products are (1,4-alpha-D-glucosyl)n-1 and (1,6-alpha-D-glucosyl)m+1.
This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is 1,4-alpha-D-glucan:1,6-alpha-D-glucan 6-alpha-D-glucosyltransferase. Other names in common use include dextrin 6-glucosyltransferase, and dextran dextrinase.
In enzymology, a 4-alpha-glucanotransferase (EC 2.4.1.25) is an enzyme that catalyzes a chemical reaction that transfers a segment of a 1,4-alpha-D-glucan to a new position in an acceptor carbohydrate, which may be glucose or a 1,4-alpha-D-glucan.
This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name of this enzyme class is 1,4-alpha-D-glucan:1,4-alpha-D-glucan 4-alpha-D-glycosyltransferase. Other names in common use include disproportionating enzyme, dextrin glycosyltransferase, D-enzyme, debranching enzyme maltodextrin glycosyltransferase, amylomaltase, and dextrin transglycosylase. This enzyme participates in starch and sucrose metabolism.
Pancreatic ?-amylase randomly cleaves the ?(1-4) glycosidic linkages of amylose to yield dextrin, maltose or maltotriose. It adopts a double displacement mechanism with retention of anomeric configuration.
Vegetable gum fiber supplements are relatively new to the market. Often sold as a powder, vegetable gum fibers dissolve easily with no aftertaste. They are effective for the treatment of irritable bowel syndrome (Parisi, 2002).[verification needed] Examples of vegetable gum fibers are guar gum (example brand Benefiber reformulated to wheat dextrin in 2006)[45] and acacia gum.
In enzymology, a cyclomaltodextrinase (EC 3.2.1.54) is an enzyme that catalyzes the chemical reaction
cyclomaltodextrin + H2O linear maltodextrin
Thus, the two substrates of this enzyme are cyclomaltodextrin and H2O, whereas its product is linear maltodextrin.
This enzyme belongs to the family of hydrolases, specifically those glycosidases that hydrolyse O- and S-glycosyl compounds. The systematic name of this enzyme class is cyclomaltodextrin dextrin-hydrolase (decyclizing). Other names in common use include cycloheptaglucanase, cyclohexaglucanase, and cyclodextrinase. This enzyme participates in starch and sucrose metabolism.
(EC 3.2.1.1 ) (CAS# 9014-71-5) (alternate names: 1,4-?-D-glucan glucanohydrolase; glycogenase) The ?-amylases are calcium metalloenzymes, completely unable to function in the absence of calcium. By acting at random locations along the starch chain, ?-amylase breaks down long-chain carbohydrates, ultimately yielding maltotriose and maltose from amylose, or maltose, glucose and "limit dextrin" from amylopectin. Because it can act anywhere on the substrate, ?-amylase tends to be faster-acting than ?-amylase. In animals, it is a major digestive enzyme and its optimum pH is 6.7-7.0. [1]
In human physiology, both the salivary and pancreatic amylases are ?-Amylases. They are discussed in much more detail
Amylase is found in saliva and breaks starch down into maltose and dextrin. This form of amylase is also called ptyalin. It will break large, insoluble starch molecules into soluble starches (amylodextrin, erythrodextrin, achrodextrin) producing successively smaller starches and ultimately maltose. Ptyalin acts on linear ?(1,4) glycosidic linkages, but compound hydrolysis requires an enzyme which acts on branched products. Salivary amylase is inactivated in the stomach by gastric acid. In gastric juice adjusted to pH 3.3, ptyalin was totally inactivated in 20 minutes at 370C. In contrast, 50% of amylase activity remained after 150 minutes of exposure to gastric juice
Amylase is found in saliva and breaks starch down into maltose and dextrin. This form of amylase is also called ptyalin. It will break large, insoluble starch molecules into soluble starches (amylodextrin, erythrodextrin, achrodextrin) producing successively smaller starches and ultimately maltose. Ptyalin acts on linear ?(1,4) glycosidic linkages, but compound hydrolysis requires an enzyme which acts on branched products. Salivary amylase is inactivated in the stomach by gastric acid. In gastric juice adjusted to pH 3.3, ptyalin was totally inactivated in 20 minutes at 370C. In contrast, 50% of amylase activity remained after 150 minutes of exposure to gastric juice
Hydrogenated starch hydrosylate (HSH) is a mixture of several sugar alcohols (a type of sugar substitute). Hydrogenated starch hydrolysates were developed by a Swedish company in the 1960's. In the United States, Hydrogenated starch hydrolysates are provided by three manufacturers The HSH family of polyols is an approved food ingredient in Canada, Japan, and Australia. HSH sweeteners provide 40 to 90 percent of the sweetness of sugar.
Hydrogenated starch hydrolysates are produced by the partial hydrolysis of starch - most often corn starch but also potato starch or wheat starch. This creates dextrins (glucose and short glucose chains). The hydrolyzed starch
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