Malic Acid in Fruits

Malic acid is one of two main organic acids that occur in most fruits. The other is citric acid. Malic acid is present in everything from beans to berries to tomatoes, though it is most often associated with apples and plums. You'll also find malic acid in processed foods, although it may or may not be derived from fruit.

Taste

Malic acid has a taste that is somewhat similar to citric acid, says Laszlo P. Somogyi, author of the book "Processing Fruits." Citric acid has a stronger taste "burst" than malic acid does, but you retain the taste of malic acid longer. Malic acid contributes strongly to the taste of green apples, for example, according to the experts at Oregon State University.

Significance

Acidity has an important role in your perception of fruit quality, says Philippe Lobit, lead author for a study published in the Journal of Experimental Botany. It affects a fruit's sweetness as well as the fruit's sour taste. Malic acid enhances your perception of sucrose, a sugar, while citric acid masks your perception of this sugar.

Identification

Fruits have varying levels of malic acid. Malic acid makes up 94 to 98 percent of the acid in apples, 85 to 95 percent of the acid in watermelon, 60 to 70 percent of the acid in bananas, 60 percent of the acid in nectarines, peaches and strawberries, 17 percent of the acid content of mangoes, 9 to 18 percent of the acid in oranges and 8 percent of the acid content in kiwis.

Considerations

Malic acid is used as a flavoring agent in a variety of processed foods. You'll find it in puddings, fruit filling, soft drinks, dry mix beverages jellies, frozen dairy products, baked goods, and confections including hard candy, according to Oregon State University. It's frequently found in fruit-flavored sodas that have a berry or apple flavor. It also can mask the off-taste of sugar substitutes in sugar-free beverages. When you look at a food label, if you see malic acid referred to as L-malic acid this means it occurs naturally. If you see racemic DL-malic acid, it does not occur naturally, according to the U.S. Food and Drug Administration. Malic acid is on the FDA's "generally recognized as safe," or GRAS, list.

Expert Insight

The amount of malic acid in a fruit can be manipulated by growing conditions such as temperature and mineral nutrition, according to Lobit. For example, adjusting the soil pH for peach trees affects malic acid amounts in the fruit. This adjustment produces different effects at different stages of peach tree growth, sometimes increasing content and sometimes lowering it. In contrast, increasing temperature reduces malic acid concentration throughout the fruit's growth cycle. However, the effect that temperature has is strongest at the beginning of the fruit ripening stage.