Structural formula of malic acid

Malic acid is a tart-tasting organic acid that plays a role in many sour or tart foods. The chemical structure of malic acid is HO₂C-CH₂-CH(OH)-CO₂H. Its chemical formula is C₄H₆0₅

Malic acid has melting point 128°C to 130°C and molecular weight of 134.09.

Apples contain malic acid, which contributes to the sourness of a green apple.

Malic acid can make a wine taste tart, although the amount decreases with increasing fruit ripeness. The process of malolactic fermentation converts malic acid to much milder lactic acid.

Malic acid, when added to food products, is denoted by E Number E296.

There is another dicarboxylic acid with the similar name maleic acid , which has the formula cis-HOOC-CH=CH-COOH . Maleic acid is the cis stereoisomer of fumaric acid, which is the trans version. These compounds are also not to be confused with malonic acid which is a dicarboxylic acid with the formula HOOC-CH₂-COOH.