Starch is a kind of high molecular carbohydrate, which is polymerized by glucose molecules. Its basic unit is α-D- glucopyranose, and its molecular formula is (C6H 10O5? Starch includes amylose and amylopectin. The former is a spiral structure without branches; The latter consists of 24~30 glucose residues connected end to end by α- 1, 4- glycosidic bond, and the branch is α- 1, 6- glycosidic bond.

People divide starch into straight-chain molecules and branched-chain molecules. The straight-chain molecule is composed of D- hexacyclic glucose through α- 1, 4- glycosidic bond, the branching position of the branched molecule is α- 1, 6- glycosidic bond, and the rest are α- 1, 4- glycosidic bond.

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Chemical properties of starch

Many chemical properties of starch are similar to glucose, but because it is a polymer of glucose, it has its own unique properties. In production, two important starch deep-processing products can be obtained by changing starch molecules by using the chemical properties of starch.

The first kind is the hydrolysis product of starch, which is the product of different DP obtained by degrading starch molecules by using the hydrolysis characteristics of starch. The α- 1, 4-glycosidic bond and α- 1, 6-glycosidic bond of starch are hydrolyzed under the action of catalysts such as acid or enzyme, and many products such as dextrin, oligosaccharide, maltose and glucose can be produced.

The second kind of product is modified starch, which is produced by the chemical reaction between starch and some chemical reagents. Under certain conditions, alcohol hydroxyl groups on C2, C3 and C6 of glucose residues in starch molecules can undergo chemical reactions such as oxidation, esterification, etherification, alkylation and crosslinking, resulting in various starch derivatives.