Preparation, purification, and identification of novel antioxidant peptides from red-bellied pacu (Piaractus brachypomus) fish meat protein hydrolysate

The current study investigates the preparation, purification, and identification of novel antioxidant peptides from Piaractus brachypomus fish (RBPF) meat. Antioxidant peptides from RBPF meat protein hydrolysate (RPMPH) were fractionated by ultrafiltration (3 kDa MWCO membrane). RPMPH-IF (MW < 3 kDa) fraction displayed significantly higher antioxidant activities (P < 0.05) (DPPH, ABTS, FRAP, and Fe2+chelating activity). RPMPH-IF was purified by Sephadex G-25 gel filtration chromatography, and the RPMPH-1 fraction exhibited significantly higher antioxidant activities (P < 0.05). Subsequently, the RPMPH-1 fraction was purified by reversed-phase high-performance liquid chromatography. RPH-8 showed the highest antioxidant activities. The sequence of peptides of the RPH-8 fraction was later identified by LC-MS/MS and MASCOT software. RPH-8 fraction showed the two peptides with MW of 1105.52 Da and 748.25 Da, and the sequence of peptides was identified as His–Asn–Leu–Gly–Leu–Leu–His–Gly–Asp–Met and Asp–Ala–Pro–Ser–Met–Asn–Asp, respectively. Thus, RPMPH or purified antioxidant peptides produced by probiotic Bacillus strain could be a bio-functional ingredient in food and nutraceutical applications.