Preparation of antioxidant peptides from oat globulin

Abstract

In order to isolate antioxidant peptides from oats globulin hydrolyzed alcalase, an antioxidant peptide was isolated and purified using ultra-filtration and ion-exchange chromatography. Hydroxyl and 1,1-diphenyl-2-pycrylhydrazyl (DPPH) radical scavenging capacity was analyzed to evaluate the antioxidant activity of peptide. Five fractions were obtained after ultra-filtration, fraction with molecular weight >10KDa showed the strongest hydroxyl and DPPH radical scavenging ability of 58.38 ± 0.87% and 24.53 ± 0.53% (p < 0.05). Fraction C which was purified via ion-exchange chromatography, exhibited the maximum antioxidant activity (IC50 of hydroxyl and DPPH radical scavenging ability was 1.83 ± 0.03 mg mL−1 and 4.11 ± 0.07 mg mL−1) among other fractions (p < 0.05). Subsequently, five antioxidant peptides were identified by electrospray ionization mass spectrometry (ESI-MS/MS), with the amino acid sequence of IRIPIL, FLKPMT, NSKNFPTL, LIGRPIIY, and FNDILRRGQLL, with a molecular weight of 723.50, 735.40, 919.48, 943.59, and 1343.76 Da, respectively.

Keywords

• antioxidant activity
• oats globulin
• hydrolysis
• purification
• amino acid sequence