Starch is a natural polysaccharide composed primarily of amylose (linear α-1,4-linked D-glucose) and amylopectin (branched with α-1,6 linkages). It serves as the primary energy storage carbohydrate in plants, found in granules within seeds, roots, and tubers. In food science, starch functions as a thickener, stabilizer, and gelling agent when heated in water, undergoing gelatinization. It is insoluble in cold water but swells and forms viscous pastes upon heating. Chemically inert under normal conditions, starch is biodegradable and widely used in culinary applications, paper manufacturing, and pharmaceuticals. Its polymeric nature results in high molecular weights ranging from 10^5 to 10^7 Da depending on source and processing.