Starch: Plants store carbohydrates in the form of starch and it is the main source of nourishment for human race. Cereal grains, seeds, roots like potato, tapioca, yam, colocasia and plantain contain considerable amount of starch. On cooking starch absorbs water and it swells and ruptures. This thickening quality of starch is used in cookery to produce a variety of dishes. Starches from different sources are used in cookery to produce a variety of dishes. Different sources of starch behave differently. Maize starch and corn flour are better ‘thickening agents’ than rice or wheat starch. All cooked starches are broken down into glucose in the digestive system.
Dextrin: When starch is partially broken into fragments either by digestion or by acids the compounds called dextrins are formed. Dextrin on further hydrolysis is broken down into maltose.
Pectin: It is a polysaccharide with no nutritional significance. It has jellying characteristic and is useful in the preparation of jam and jelly. It contributes to the palatability of foods.
Glycogen: Animals store carbohydrate in the body as glycogen. It is stored in the liver and muscles. This is the form of immediate energy for the body. It is also known as animal starch.
Cellulose: It is an insoluble, indigestible polysaccharide. More than 3000 glucose units are there in cellulose but it is not of human utilization. Cattle can digest cellulose. Even though it is not of much food value it provides bulk to the diet and thus helps in movements of the large intestine. It prevents constipation and to an extent, cancer of the bowel. It helps in reducing the cholesterol level in blood as well as body weight. A high fibre diet can help in the treatment of obesity as it delays digestion and contributes satiety to obese people.