Main Page | See live article | Alphabetical index 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. 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. This article is a stub. You can help Wikipedia by fixing it. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.