title: Antioxidant properties of peptide fractions from silver carp (Hypophthalmichthys molitrix) processing by-product protein hydrolysates evaluated by electron spin resonance spectrometry.
abstract: Silver carp processing by-product protein is usually discarded as an industrial solid waste. In this study the protein was recovered using a pH-shift method, after which seven commercial proteases were separately employed to prepare antioxidative hydrolysates. Among the hydrolysates, pepsin hydrolysates, which had the highest free radical-scavenging activity, were further separated into five peptide fractions, SCPH-I (>10kDa), SCPH-II (5-10kDa), SCPH-III (3-5kDa), SCPH-IV (1-3kDa), and SCPH-V (<1kDa), by using ultrafiltration. The antioxidative properties of the peptide fractions were investigated, using a free radical-scavenging assay, by electron spin resonance. The results show that SCPH-V had the highest scavenging effects on DPPH (1,1-diphenyl-2-picrylhydrazyl), hydroxyl and superoxide anion radicals. SCPH-V had potent antioxidant activity in the prevention of the peroxidation of linoleic acid and alleviation of H2O2-induced oxidative stress in human intestinal epithelial caco-2 cells. The results indicated that the antioxidant capacity of silver carp by-product hydrolysates could be enhanced by ultrafiltration.
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Saiyi
authors.initials: S
authors.lastname: Zhong
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China. Electronic address: chwma@cau.edu.cn.
authors.forename: Changwei
authors.initials: C
authors.lastname: Ma
authors.affiliation: Laboratory of Reproductive and Molecular Endocrinology, College of Veterinary Medicine, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210, USA; OSU Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA.
authors.forename: Young C
authors.initials: YC
authors.lastname: Lin
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Yongkang
authors.initials: Y
authors.lastname: Luo
keywords: Antioxidant activity; Electron spin resonance; Peptide fractions; Protein hydrolysates; Silver carp by-product