malic acid, one of the two principal organic acids of grapes and wines (see also tartaric acid). Its name comes from malum, Latin for apple, the fruit in which it was first identified by early scientists. Present in nearly all fruits and berries, malic acid is now known to be one of the compounds involved in the complicated cycles of reactions by which plants and animals obtain the energy necessary for life. One of these cycles of reactions is known as the citric acid, Krebs, or tricarboxylic acid cycle and its elucidation was one of the outstanding triumphs of biochemistry.
