Structural and functional properties of food protein-derived antioxidant peptides

The aim of this work is to provide a timely examination of the structure-activity relationship of antioxidative peptides. The main production approach involves enzymatic hydrolysis of animal and plant proteins to produce protein hydrolyzates, which can be further processed by membrane ultrafiltration into size-based peptide fractions. The hydrolyzates and peptide fractions can also be subjected to separation by column chromatography to obtain pure peptides. Although the structural basis for enhanced antioxidant activity varies, protein hydrolyzates and peptide fractions that contain largely low molecular weight peptides have generally been shown to be potent antioxidants. In addition to having hydrophobic amino acids such as Leu or Val in their N-terminal regions, protein hydrolyzates, and peptides containing the nucleophilic sulfur-containing amino acid residues (Cys and Met), aromatic amino acid residues (Phe, Trp, and Tyr) and/or the imidazole ring-containing His have been generally found to possess strong antioxidant properties.