Antioxidant activities against hypochlorite ions and peroxyl radicals of a chicken dark meat hydrolysate digested with pepsin were examined with the myoglobin method based on the structure change of myoglobin due to redox reaction with reactive oxygen species (ROS). A peptide that showed strong antioxidant activity against the peroxyl radical was isolated from the hydrolysate using HPLC equipped with a hydrophobic-interacting column. The sequence of the first five amino acid residues of the peptide was determined as YASGR (Tyr-Ala-Ser-Gly-Arg), and this sequence matched with the amino acid residues 143-147 of chicken β-actin (GenBank: CAA25004.1). The synthetic peptide YASGR showed very high antioxidant activity against the peroxyl radical. Antioxidant activities of the free amino acids, confirmed that the tyrosine residue of this peptide was possibly responsible for antioxidant activity.
Keywords: Antioxidant; Chicken meat; Myoglobin; Peptide; Peroxyl radical.