The Strategy for Screening of Antioxidant Constituents in Protein Hydrolysates

Abstract

More than 100 antioxidant peptides have been identified recently in protein hydrolysates and fermented foodstuffs. Antioxidant activity of peptides is essential both for their application as functional food ingredients or biopharmaceuticals and technological application as antioxidant additives. Most of known antioxidant peptides contain redox amino acids residues. However, structure–activity relationships for antioxidant peptides have not been established yet in particular the preferential positions of redox amino acid residues (a.a.r.) in peptides and their superposition. The study was aimed to develop a knowledge-based strategy for screening of antioxidant peptides in protein hydrolysates using the structural descriptors of antioxidant peptides. Antioxidant capacity (AOC) of amino acids and tyrosine-containing peptides was determined by Trolox Equivalent AOC assay. The following structural descriptors of tyrosine-containing antioxidant peptides were disclosed: preferred N-terminal Y position, presence of sequences (YH, MY) with intermolecular synergistic effects between neighboring redox-active a.a.r., presence of KY sequence with positive effect of positively charged K residue on antioxidant properties of tyrosine residue. Based on those descriptors, 16 novel antioxidant peptides were identified in poultry protein hydrolysates (PH) obtained by enzymatic conversion of meat and bone trimmings. Further in vivo experiments indicated essential role of antioxidant peptides for maintaining of antioxidant status in central nervous system. Overall, the findings demonstrated the feasibility of the strategy proposed for screening of antioxidant peptides in protein hydrolysates.