LAUSR

The goals of this study were to determine antioxidant activities of water soluble fractions of a Loma fermented fish extract and identify the novel antioxidant peptides by HPLC connected to the tandem mass spectrometry (LC/MS/MS). The antioxidant activities of Loma fermented fish (LFF) were measured by evaluating 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activities. Antioxidant peptides from LFF were separated using ultrafiltration, size exclusion chromatography and HPLC. Purified fraction (FIII 3), which exhibited the strongest ABTS radical scavenging activity, with the IC50 value of 0.636 mg/ml, had higher antioxidant activity than the LFF sample without fractionation (with IC50 of 2.24 mg/ml). Two novel peptides were identified as Ala-Ile-Pro-Pro-His-Pro-Tyr-Pro (AIPPHPYP) and Ile-Ala-Glu-Val-Phe-Leu-Ile-Tre-Asp-Pro-Lys (IAEVFLITDPK). The IAEVFLITDPK peptide demonstrated higher antioxidant activity than the AIPPHPYP. The presence of hydrophobic amino acids (Ile, Ala and Pro), and basic amino acids, (Lys) in the peptide sequences is believed to contribute to the high antioxidant activity of the LFF. Therefore, these peptides may have the potential as a natural functional ingredient in food and pharmaceutical industries.