CHEMISTRY OF SORBATES - A BASIC PERSPECTIVE

Sorbic acid and its potassium and calcium salts are used as preservati ves in a large number of foods, feeds, pharmaceuticals, and cosmetics. In the dry and crystalline state, sorbic acid is stable and no degrad ation occurs even if stored at room temperature for a long time. Howev er, in solutions and in foods, it undergoes autoxidation during storag e, forming carbonyls and other compounds. Many factors (e.g., pH, temp erature, packaging, water activity, and composition of food) influence its stability. Degradation of sorbic acid is associated with developm ent of browning in foods. Acetaldehyde and beta-carboxylacrolein have been reported to be the major degradation products of sorbic acid in a queous solutions. beta-Carboxylacrolein is found to be responsible for sorbate-induced browning in foods as it reacts with amino acids and p roteins to form brown pigments. Since sorbic acid mainly degrades by a utoxidation, deoxygenation and vacuum packaging in oxygen impermeable films or laminates have been suggested to reduce its degradation and e nsure adequate shelf-life of sorbate-preserved foods.