Abstract:In order to make efficient use of protein resources in Moringa oleifera leaves, bioactive peptides from Moringa oleifera leaves were prepared by solid-state fermentation. Firstly, the optimal strains were selected from Aspergillus oryzae and Aspergillus niger with enzyme activity and peptide content as indexes. Then, the effects of fermentation time, water content, initial pH and inoculum amount on peptide content were studied. The fermentation process was optimized by response surface methodology. The antioxidant activity and amino acid composition of Moringa oleifera leaves bioactive peptides were studied. The results showed that the optimum conditions were as follows: Aspergillus oryzae was the best strain, fermentation temperature was 30 ℃, fermentation time was 72 h, medium moisture content was 52.39%, inoculum volume was 14.71%, pH was 5. Under the optimal fermentation conditions, the Moringa oleifera leaves bioactive peptides had good DPPH free radical scavenging rate (EC50=1.0927 mg/mL), ABTS free radical scavenging rate (EC50=0.059 mg/mL) and Fe2+ chelating rate (EC50=9.76 mg/mL). Seventeen kinds of amino acids were detected in the bioactive peptides of Moringa oleifera leaves, and the contents of acid amino acids (Glu and Asp) and hydrophobic amino acids (Tyr) with antioxidant function were abundant. The results provide basic research data for the high value utilization of Moringa oleifera leaves and the research and development of natural antioxidant food.
