Antioxidant activity of fermented meat sauce and isolation of an associated antioxidant peptide

The present study was carried out to investigate the radical scavenging and antioxidant activities of fermented meat sauce (FMS) against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the hydroxyl radical (OH-radical), as well as to isolate substances in FMS related to its antioxidant activity. FMS was prepared by mixing ground pork, koji (rice fermented with koji mold such as Aspergillus), and salt, and fermenting for 24 weeks. High antioxidant activities against the DPPH radical and the OH-radical in FMS were observed as about 0.55 mu mol Trolox eq./ml and 61.2%, respectively. DPPH radical scavenging activities were related to time-dependent changes in proteolysis and antioxidant peptides could be generated in FMS by proteolysis. Liquid chromatography-mass spectrometry analysis detected a substance of molecular weight 406.26 g/mol from the purified peptide fraction, which showed an extremely high antioxidant activity against the OH-radical that was greater than 90%. This substance was anticipated to be the tripeptide Gln-Tyr-Pro. (C) 2015 Elsevier Ltd. All rights reserved.