Antioxidative peptides derived from milk proteins

Antioxidants may function by preventing the formation of radicals or by scavenging radicals or hydrogen peroxide and other peroxides. Milk contains several antioxidant factors, like vitamins and enzymes. Possible antioxidant activity of milk proteins and hydrolysates has also been shown. Peptides generated from the digestion of milk proteins are reported to have antioxidative activities. Milk-derived antioxidative peptides are composed of 5-11 amino acids including hydrophobic amino acids, proline, histidine, tyrosine or tryptophan in the sequence. The structure-activity relationship or the antioxidant mechanism of peptides is not fully understood. Antioxidant activity of the hydrolysates seems to be inherent to the characteristic amino acid sequences of peptides derived, depending on the protease specificity. The results suggest that the hydrolysates from milk proteins could be used as natural antioxidants in enhancing antioxidant properties of functional foods and in preventing oxidation reaction in food processing. Further studies are needed to elucidate the role of antioxidative peptides in the protective function in humans. (c) 2006 Elsevier Ltd. All rights reserved.