Caffeine is a plant alkaloid. Pure caffeine is white, odorless, and has a strong bitter acicular or powdery taste. Caffeine is slightly soluble in water, petroleum ether, ether and benzene, but soluble in ethyl acetate, chloroform, pyrimidine, tetrahydrofuran, alcohol and acetone. Caffeine is found in many plants. The most commonly used caffeinated plants include coffee, tea and cocoa.
Caffeine is a stimulant of the central nervous system and a stimulant of metabolism. Caffeine is not only used as a drink, but also as a drug. Its role is to refresh and relieve fatigue. Eating caffeine does not reduce the amount of sleep required, but temporarily reduces the feeling of sleepy.
GB 2760-2011 "Food Safety National Standards for the Use of Food Additives" specifies the specific use of caffeine as shown in the table below.
Remarks on the maximum use of food names (g/kg)
Cola carbonated drinks 0.15