In vitroand in vivoantioxidant activity and umami taste of peptides (<1 kDa) from porcine bone protein extract

The antioxidant activity in vivoand in vitroof peptides with <1 kDa molecular weight were measured after purification of the enzymatic hydrolysates (FlavourzymeTMand Papain PSM500 together) of porcine bone protein extracts (EH-PBPE). Amino acid sequences of peptides responsible for its characteristic umami taste were identified as Ser-Tyr, Pro-Asn, Gly-Ser, Lys-Pro, and Ala-Pro-His-Arg. The umami compounds were purified using ultrafiltration, gel filtration chromatography, preparative high-performance liquid chromatography, and liquid chromatography-tandem mass spectrometry (LC-MS); and sensory evaluations were done. The in vitroantioxidant activity (as DPPH radical-scavenging activity) of the peptide was 62.9% and umami score (estimated using sensory evaluation) was 8.9 out of 10. Subsequent in vivostudies on antioxidant activities (superoxide dismutase activity and malondialdehyde, glutathione, and protein carbonyl content) of the <1 kDa fraction showed a significant difference from those of the control group, in a dose-dependent manner. In total, 5 peptides were found in the <1 kDa fraction of EH-PBPE using LC-MS. These results suggested that the <1 kDa peptide fraction purified from EH-PBPE might be used as a natural antioxidant to offset oxidative stress.