Malic acid is an organic compound with the formula HO2CCH2CHOHCO2H. It is a dicarboxylic acid which 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.
Malic acid in food
Malic acid was first isolated from apple juice by Carl Wilhelm Scheele in 1785. Antoine Lavoisier in 1787 proposed the name acide malique which is derived from the Latin word for apple, mālum.[3] Malic acid contributes to the sourness of green apples. It is present in grapes and in most wines with concentrations sometimes as high as 5 g/l.[4] It confers a tart taste to wine, although the amount decreases with increasing fruit ripeness. The process of malolactic fermentation converts malic acid to much milder lactic acid. Malic acid occurs naturally in all fruits and many vegetables, and is generated in fruit metabolism.[5]
Malic acid, when added to food products, is denoted by E number E296. Malic acid is the source of extreme tartness in USA-produced confectionery, the so-called extreme candy. It is also used with or in place of the less sour citric acid in sour sweets.
These sweets are sometimes labeled with a warning stating that excessive consumption can cause irritation of the mouth. It is approved for use as a food additive in the EU,[6] USA[7] and Australia and New Zealand[8] (where it is listed by its INS number 296).
Source :
http://en.wikipedia.org/wiki/Malic_acid