Starches in food
Plant cells store glucose as starches – long branches or unbranched chains of hundreds or thousands of glucose molecules linked together.
It is a plant polysaccharide stored in roots and seeds of plants and is in the endosperm of a grain kernel. It provides humans with energy 4 cal per gram and is hydrolyzed to glucose.
It occurs in the form of granules, which are usually an irregular rounded shape, ranging in size from 2 to 100um. Both the shapes and sizes of the granules are characteristics of the species of plant and can help to identify the origin of a starch or flour.
Starch from plants is used to produce various foods such as bread and pasta. Many vegetables such as corn and potatoes also contain starch.
Starch is made up to two molecules, amylose and amylopectin, whose parts are connected by glycosidic linkages. Amylose molecules typically make up approximately one-quarter of starch.
Most starches have 20-25% amylose. However, pea starch is 60% amylose.
In foods products, modified starch thickens readymade sauces; adds a sheen to cake frostings, jelly beans and wine gums; and improves the texture, or ‘mouth feel’, of puddings, pie fillings and even baby foods.
