Preparation of Antioxidant Peptides by Microwave-assisted Enzymatic Hydrolysis of Moringa Meal Albumin and Process Optimization

Abstract

【Objective】The optimal protease for enzymatic hydrolysis of Moringa meal albumin was screened, and the antioxidant peptides of Moringa meal were prepared by microwave-assisted enzymatic hydrolysis.【Method】With the degree of hydrolysis as an index, alkaline protease, trypsin, flavour protease, complex protease, bromelain and papain was used to carry out primary screening and re-screening, and the best protease was screened out. The optimal enzymatic hydrolysis conditions were screened out by single factor experiments and response surface methodology, and the enzymatic hydrolysis process was further optimized by microwave. The antioxidant activity of Moringa meal albumin was evaluated by measuring DPPH· clearance rate, O2-· clearance rate, ABTS+· clearance rate and reducing capacity.【Result】Moringa meal albumin was the best protein for enzymatic hydrolysis, and flavor protease was the optimal protease. By single factor experiments and response surface methodology, the optimal enzymatic hydrolysis process was obtained as: enzyme volume 7 491.44 U/g, substrate concentration 9.36%, pH 7.50, enzymolysis temperature 45℃, and hydrolysis for 3.88 h. Under this enzymatic hydrolysis condition, the yield of antioxidant peptide was 19.09%, and the degree of hydrolysis was 69.80%. The enzymolysis time was further shortened to 1 h by low-power microwave equipment (0-100W), which could also improve the antioxidant activity of the enzymatic hydrolysates. Furthermore, Moringa oleifera meal hydrolysates had good antioxidant activity, the best mass concentrations for scavenging DPPH·, ABTS+· and O2-· were 10 mg/mL, 50 mg/mL and 50 mg/mL respectively, and the best mass concentration for reducing Fe3+ was 50 mg/mL, which was comparable to the positive control Vc.【Conclusion】Moringa meal has the potential to prepare natural antioxidant peptides, while low-power microwave can improve enzymatic hydrolysis efficiency and antioxidant activity.

Keywords

• moringa meal
• albumin
• response surface analysis
• low-power microwave
• antioxidant peptide