A substance belonging to that group of carbohydrate known as the amyloses. It is the form in which utilisable CARBOHYDRATE is stored in granules within the seeds and roots of many plants.
Starch is converted into sugar when treated with heat in presence of a dilute acid. It is changed largely into dextrin when exposed to a considerable degree of dry heat, as in toasting bread; and a similar change into dextrin and malt-sugar takes place under the action of various enzymes (see ENZYME) such as the PTYALIN of the SALIVA. Starch forms a chief constituent of the carbohydrate foods (see DIET); and in the process of digestion, the above-mentioned change takes place to prepare it for absorption. It is also slowly broken down in the process of cooking.
Starch is used as a constituent of dusting powders for application to chafed or irritable areas of the skin.
n. the form in which *carbohydrates are stored in many plants and a major constituent of the diet. Starch consists of linked glucose units and occurs in two forms, ?-amylose and amylopectin. In ?-amylose the units are in the form of a long unbranched chain; in amylopectin they form a branched chain. The presence of starch can be detected using iodine: ?-amylose gives a blue colour with iodine; amylopectin a red colour. Starch is digested by means of the enzyme *amylase. See also dextrin.
Along with DEXTRAN and GELATIN, this is a substance with a large molecular structure used to treat shocked patients with burns (see BURNS AND SCALDS) or SEPTICAEMIA in order to expand and maintain their blood volume. Like other plasma substitutes, this form of starch can be used as an emergency, short-term treatment for severe bleeding until blood for transfusion is available. Plasma substitutes must be used with caution in patients who have heart disease or impairment of their kidney function. Patients should be monitored for hypersensitivity reactions and for changes in their BLOOD PRESSURE (see SHOCK).... etherified starch
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