What are Carbohydrates
Carbohydrates are a combination of carbon and water. For each atom of carbon, there is one molecule of water. However, the word carbohydrate does not name just one thing. Rather, it identifies a large group of substances, barely understood. The most common carbohydrates of nutritional importance are the sugars, the starches, and dietary fiber.
Sugars and Starches
A large variety of sugar exists in nature, made up of a varying number of carbon atoms to which are attached atoms of hydrogen and oxygen. Those with five carbons are called pentoses, while those with six are termed hexoses. Food sugars, which come from the hexoses, are found singly and in pairs. Starches are long chains of glucose molecules, 30 or more in length. The starches present in different foods differ one from another. In general, the food energy in fruit is in the form of sugar – usually mixtures of sucrose and fructose. In grains and vegetables, it is in the form of starch. Examples include bread, potatoes, cassava, legumes, and cornstarch. The food energy of bananas before they are ripe is starch, which on ripening is converted to sugar, giving ripe bananas their sweeter taste. Immature green peas, on the other hand, are sweet because of their sugar content, whereas on maturing the sugar changes to starch.
After digestion, all carbohydrates enter the blood as glucose, which constitutes the principal source of energy for the body’s muscles, brain, and tissue cells.
