Study on preparation and antioxidant activity of Maca peptide

The degree of hydrolysis used as response value,the enzymatic hydrolysis condition of Maca protein which prepare for Maca peptide was optimized with orthogonal test experiment,and·OH,DPPH and O₂^-·scavenging activities were tested for antioxidant activity evaluation.The results showed that the most suitable enzyme was alkaline protease,alkaline protease optimal preparation conditions of Maca peptide were as follow:time 4 h,pH10.5,temperature 55℃,the amount of enzyme 1.6×10⁴ U/g. Under this condition, the preparation of Maca polypeptide hydrolysis was(31.55%±0.74%). Scavenging radicals ability of double dilution of maca alcohol was maximum, the scavenging rate of DPPH was 94.44%, the scavenging rate of·OH was 85.05%,the scavenging rate of O₂^-·was 53.85%.IC₅₀ values of Maca peptide scavenged DPPH,·OH and O₂^-·were 0.85, 0.44,0.86 mg/mL,and its antioxidant capacity increased with the concentration.In addition,the four amino acid compositions of Maca peptide:Tyr, his, Lys, Pro, their contents were 16.98%, the amino acid composition have a certain relationship with antioxidant activity.The results showed that both of Maca alcohol and Maca peptide have antioxidant activity.