The primary acid found in apples is malic acid.
Malic acid is a dicarboxylic acid that contributes to the tart or sour taste of apples. The concentration of malic acid varies depending on the apple variety and ripeness. Unripe apples contain higher concentrations of malic acid, resulting in a more sour flavor. As apples ripen, the amount of malic acid decreases, leading to a sweeter taste.
Besides contributing to the flavor profile, malic acid plays a role in the metabolic processes of the apple fruit. It's involved in energy production and the synthesis of other organic compounds.
While malic acid is the predominant acid, other acids, such as citric acid, are also present in smaller amounts in apples. However, malic acid is the characteristic acid that defines the flavor of apples.
