What is "acidulant"

n. A food additive used to increase acidity or to give a tart taste

Acidulants are chemical compounds that confer a tart, sour, or acidic flavor to foods. They differ from acidity regulators, which are food additives intended to modify the stability of food or enzymes within it. Typical acidulants are acetic acid, e.g. in pickles. citric acid. Many beverages, such as colas, contain phosphoric acid. Sour candies often are formulated with malic acid.