starch

Pronunciation: starch

Definition: A high molecular weight polysaccharide made up of d-glucose residues consisting of 20% amylose and 80% amylopectin. amylose contains α-1,4 linkages, differing from cellulose in the presence of α- rather than β-glucoside linkages, and amylopectin contains additional α-1,6 linkages; both amylose and amylopectin exist in most most plant tissues. Starch is converted into dextrin when subject to the action of dry heat, and into dextrin and d-glucose by amylases and glucoamylases in saliva and pancreatic juice; used as a dusting powder, an emollient, and an ingredient in medicinal tablets; is an important raw material for the manufacture of alcohol, acetone, n-butanol, lactic acid, citric acid, glycerine, and gluconic acid by fermentation; is the chief storage carbohydrate in most higher plants.

Synonym(s): amylum

[A.S. stearc, strong]

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