What Is The Composition Of Starch?

Starch is the storage food of plants (potatoes, yams, cereals).It is an important constituents of food for animals including humans. Many countries of the world9 such as those of Africa, South America and Asia) have foods rich in starch, such as rice , potatoes, yams, cereal products and vegetables 9legumes).

Starches in different plants differ somewhat from each other in the nature of their granules. Two types of starch molecules exist:
Amylose a straight chain glucose polymer or glucosan.

Amylopectin a highly branched glucose polymer consisting of many more glucose molecules. It is somewhat more soluble in water.

Starch can be decomposed by hydrolysis into its constituents glucose molecules, with the aid of inorganic acids or enzymes 9diastases). The diastases in the digestive tract, called amylases, catalyze the hydrolysis of starch into simpler substance dextrin, maltose and then, finally, glucose.

When bread is toasted, the starch is changed into dextrin, which gives the bread a different taste and texture. Dextrin and maltose are much more readily digested. They are, therefore, used infant feeding formula, where they prevent the milk from forming large, heavy curds in the infant's stomach.

Starch forms an intense as a test for starch. Most dextrin produces a red color with iodine, while maltose produces no color.