The Collaborative International Dictionary of English v.0.48:

Malic \Ma"lic\, a. [L. malum an apple: cf. F. malique.] (Chem.)
   Pertaining to, or obtained from, apples; as, malic acid.
   [1913 Webster]

   Malic acid, (Chem.) a hydroxy acid
      (HO.CO.CH2.CH(OH).CO.OH) obtained from unripe fruit
      (such as green apples, currants, tomatoes or cherries) as
      a substance which is sirupy or crystallized with
      difficulty, and has a strong but pleasant sour taste. It
      is levorotatory or dextrorotatory according to the
      temperature and concentration; the natural form is of L-
      conformation. A synthetic variety is a derivative of
      succinic acid, but as with most simple synthetic
      compounds, is a racemic mixture of isomers and thus has no
      rotatory action on polarized light.
      [1913 Webster +PJC]