Starch is a kind of high molecular carbohydrate, which is a polysaccharide polymerized by glucose molecules. Its basic unit is α-D- glucopyranose, and its molecular formula is (C6h10o5) n.

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.

physical features

1, adsorption characteristics

Starch can adsorb a variety of organic and inorganic compounds, and amylose and amylopectin have different adsorption properties due to different molecular morphology. Amylose molecules have good molecular ductility in solution, and are easy to associate with some polar organic compounds such as n-butanol and fatty acids through hydrogen bonds to form crystalline complexes and precipitate.

2. Solubility

The solubility of starch refers to the mass fraction of starch sample molecules dissolved after heating in water for 30min at a certain temperature. Starch granules are insoluble in cold water, and damaged starch or chemically modified starch can be soluble in cold water, but the dissolved swollen starch is irreversible. The swelling degree and solubility of starch increase with the increase of temperature.