Carbohydrate granules of varying size obtained from roots, bulbs and seeds of most plants. Starch is primarily obtained from rice, wheat, corn, potatoes, cassava (tapioca), sago and arrowroot. The white, powdery granules range in size from 3-150 micrometers. Starch is a mixture of the soluble straight-chain amylose molecules and the insoluble, branched-chain amylopectin molecules. When starch is heated, the granules swell and form a thick, tacky jelly upon cooling. Starchy adhesives have been used since at least 3500 BCE in Egypt. Starch is sensitive to moisture and biodegradation. Paste films become brittle with age. Dextrin is prepared from starch by baking it at 200-2508C until the material becomes completely soluble in cool water. Soluble starch can also be made by hydrolysing the granules with dilute hydrochloric acid followed by neutralisation with an alkali. Soluble starch has been used as a binder in watercolour paints. Synonyms: fecula; wheat; corn; rice; potato; tapioca; arrowroot; sago palm; amylum. Museum of Fine Arts, Boston (2000). [J. Cassar, R. de Angelis]