Malic acid

is a white, crystal powder with sour taste, that was found 1785 in apple juice. It is a chemical compound that occurs as left-turning L-malic acid and right-turning D-malic acid. In nature the L-malic acid occurs in unripe fruits to prevent to be eaten. During ripening malic acid is degraded. It is obtained by a chemical process from fumaric acid or maleic acid and is a mixture of D- and L-malic acid. The malic acid is soluble in water and in ethanol. The product results as an intermediate of the energy metabolism of every living cell. For humans it is one kg a day. The esters and salts are called malates.