The main functional components of coffee are caffeine, tannic acid and acidic fat. Caffeine can stimulate the central nervous system, heart and respiratory system. Moderate caffeine can also reduce muscle fatigue and promote the secretion of digestive juice, but excessive intake will lead to caffeine poisoning. Each 100g coffee bean contains 6g of protein, 6g of fat 16g, 7g of sugar, 9g of cellulose, 8g of tannin and 3g of caffeine. Caffeine, also known as caffeine, is an alkaloid commonly found in tea or coffee. Its main function is to excite the central nervous system, and it is often used as pharmaceutical raw materials.