What is "malic acid"

Malic \Ma"lic\, a. [L. malum an apple: cf. F. malique.] (Chem.) Pertaining to, or obtained from, apples; as, malic acid.

Malic acid, (Chem.) a hydroxy acid ( HO.CO.CH2.CH(OH).CO.OH) obtained from unripe fruit (such as green apples, currants, tomatoes or cherries) as a substance which is sirupy or crystallized with difficulty, and has a strong but pleasant sour taste. It is levorotatory or dextrorotatory according to the temperature and concentration; the natural form is of L- conformation. A synthetic variety is a derivative of succinic acid, but as with most simple synthetic compounds, is a racemic mixture of isomers and thus has no rotatory action on polarized light.

n. (context organic compound English) A colourless crystalline dicarboxylic acid, hydroxy-malonic acid, found in wine, apples and other fruit; it is converted to lactic acid by malo-lactic fermentation.

Malic acid is an organic compound with the molecular formula CHO. It is a dicarboxylic acid that is made by all living organisms, contributes to the pleasantly sour taste of fruits, and is used as a food additive. Malic acid has two stereoisomeric forms (L- and D-enantiomers), though only the L-isomer exists naturally. The salts and esters of malic acid are known as malates. The malate anion is an intermediate in the citric acid cycle.