Identification and characterization of antioxidant peptides from hydrolysate of blue-spotted stingray and their stability against thermal, pH and simulated gastrointestinal digestion treatments.

Affiliation

Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman, 31900 Kampar, Malaysia; Centre for Biodiversity Research, Universiti Tunku Abdul Rahman, 31900 Kampar, Malaysia. Electronic address: [Email]

Abstract

This study was conducted to identify and characterize antioxidant peptides from the alcalase hydrolysate of the blue-spotted stingray. Purification steps guided by ABTS cation radical (ABTS+) scavenging assay and de novo peptide sequencing produced two peptides, WAFAPA (661.3224 Da) and MYPGLA (650.3098 Da). WAFAPA (EC50 = 12.6 µM) had stronger antioxidant activity than glutathione (EC50 = 13.7 µM) and MYPGLA (EC50 = 19.8 µM). Synergism between WAFAPA and MYPGLA was detected. WAFAPA and MYPGLA surpassed carnosine in their ability to suppress H2O2-induced lipid oxidation. The peptides protected plasmid DNA and proteins from Fenton's reagent-induced oxidative damage. Thermal (25-100 °C) and pH 3-11 treatments did not alter antioxidant activity of the peptides. MYPGLA maintained its antioxidant activity after simulated gastrointestinal digestion, whereas WAFAPA showed a partial loss. The two peptides may have potential applications as functional food ingredients or nutraceuticals, whether used singly or in combination.

Keywords

Antioxidant peptide,DNA oxidation,Lipid peroxidation,Protein oxidation,Purification,Simulated gastrointestinal digestion,Thermal treatment,pH stability,