Starch

By far the most important polysaccharide for the cook is starch, the compact, unreactive polymer in which plants store their supply of sugar. Starch is simply a chain of glucose sugars. Plants produce starch in two different configurations: a completely linear chain called amylose, and a highly branched form called amylopectin, each of which may contain thousands of glucose units. Starch molecules are deposited together in a series of concentric layers to form solid microscopic granules. When starchy plant tissue is cooked in water, the granules absorb water, swell, and release starch molecules; when cooled again, the starch molecules rebond to each other and can form a moist but solid gel. Various aspects of starch—the way it determines the texture of cooked rice, its formation into pure starch noodles, its role in breads, pastries, and sauces—are described in detail in chapters 9–11.