Carbohydrate consists of three elements: carbon, hydrogen and oxygen. It is the most abundant organic compound with broad-spectrum chemical structure and biological function in nature. It can be represented by the general formula CX (H2O) y. Because it contains two to one hydrogen and oxygen like water, it is called carbohydrate. It can provide heat energy for human body.
Carbohydrates in food are divided into two categories: effective carbohydrates that people can absorb and utilize and ineffective carbohydrates that people can't digest. Carbohydrate is the main source of energy needed by all living things to maintain life activities. It is not only a nutrient, but also some of them have special physiological activities.
Before people knew the chemical properties and composition of carbohydrates, carbohydrates had been well used. Now, plants rich in carbohydrates are used as food to make fermented drinks and animal feed. It was not until the18th century that a German scholar separated pure sugar from beet and glucose from grape that the research on carbohydrates developed rapidly.