Isolation, Identification and Stability Analysis of Antioxidant Peptides from Moringa oleifera Seeds

Moringa oleifera seed protein was hydrolyzed with alkaline protease to prepare antioxidant peptides, which were purified by ultrafiltration, Sephadex G-15 dextran gel column chromatography. Antioxidant peptide sequence was identified by LC-MS/MS. The effects of pH, metal ions, and temperature on the activity of Moringa oleifera seed antioxidant peptides were analyzed. The results showed that when the concentration of the enzymatic hydrolysate, ultrafiltration product (<3 kDa), and column chromatography separation was 8 mg/mL, the corresponding reduction capacity absorption value were 0.21, 0.75 and 0.83, respectively; when the three concentrations were 0.6 mg/mL, the corresponding free radical scavenging rates were 50%, 65% and 71%, respectively. Five antioxidant peptide sequences were identified by purified column chromatography. Stability studies showed that Moringa oleifera seed antioxidant peptides had good temperature and pH stability, and its activity increased by 4% when heated at 65 ℃ for 30 min. The concentration of K⁺, Cu²⁺, Mg²⁺ and Ca²⁺ at 0.25~2 mmol/L at room temperature could improve the DPPH free radical scavenging rate of Moringa oleifera seed antioxidant peptides. In summary, Moringa oleifera seed antioxidant peptide has antioxidant activity and processing stability, which can provide reference for the development and utilization of Moringa oleifera seed antioxidant peptide.