Malic acid includes D-malic acid, DL-malic acid and L-malic acid. L-malic acid, also known as 2-hydroxybutanedioic acid, is a cyclic intermediate of tricarboxylic acids in organisms and is easily absorbed by the human body. Therefore, it is widely used as an excellent food additive and functional food in the fields of food, cosmetics, medical care and health products. Malic acid, also known as 2-hydroxybutanedioic acid, has two stereoisomers due to the presence of an asymmetric carbon atom in the Chemicalbook molecule. In nature, it exists in three forms, namely D-malic acid, L-malic acid and its mixture DL-malic acid. Malic acid is a white crystalline or crystalline powder with strong hygroscopicity and is readily soluble in water and ethanol. It has a particularly pleasant sour taste. L-malic acid is mainly used in the food and pharmaceutical industries.