Malic acid, also known as 2 – hydroxy succinic acid, because have an asymmetric carbon atoms in molecules, there are two stereo isomer. In nature, exist in three forms, namely D – malic acid, DL – L – malic acid and its mixture of malic acid. White crystal or crystalline powder, has the strong moisture absorption, easy to dissolve in water, ethanol. There is a special pleasant acidity. Malic acid is mainly used in food and pharmaceutical industries.