Purification and characterisation of a new antioxidant peptide from chickpea (Cicer arietium L.) protein hydrolysates.

An antioxidant peptide was purified using consecutive chromatographic methods from chickpea protein hydrolysates (CPH). This peptide was designated as Fra.7. It had a molecular weight of 717.37Da, and its amino acid sequence was identified as Asn-Arg-Tyr-His-Glu by an ABI 4700 proteomics analyser. This antioxidant peptide was identified for the first time from food-derived protein hydrolysates. The molar ratio of the five amino acids in the sequence was 1:1:1:1:1. This antioxidant peptide efficiently quenched the free radical sources 1,1-diphenyl-2-pycryl-hydrazyl (DPPH), hydroxyl, and superoxide free radicals. The Cu(2+) and Fe(2+) chelating activities were 76.92% and 63.08% at the peptide concentration of 50μgmL(-1), respectively. Furthermore, the inhibition of the Fra.7 on lipid peroxidation was greater than that of α-tocopherol. The inhibition ratio of the linoleic acid autooxidation was 88.81% at the eighth day of analysis.