Abstract:In this study, based on enzymatic hydrolysis and response surface method, the process of enzymatic hydrolysis of silkworm pupa protein by alkaline protease was optimized by increasing the response value in response surface method. DPPH and ABTS free radical scavenging rates were used as the evaluation indexes of hydrolyzed peptides to screen and find an enzymatic hydrolysis process with strong antioxidant activity. The optimal enzyme was alkaline protease. The optimal conditions were pH 9.0, temperature 48 °C, substrate mass fraction 4.1 %, reaction time 2 h, and enzyme mass fraction 3.0 %. Compared with the existing process, the reaction time and temperature were shortened and reduced, and the antioxidant activity in vitro was improved. The antioxidant activity in vitro reached 89.10% of Vc. On this basis, the antioxidant activity of the silkworm pupa peptide in vivo was evaluated by using the oxidative stress mouse model induced by D-galactose. The low-dose group of silkworm pupa peptide could restore the CK, SOD, T-AOC and GSH-PX factors in serum to 0.31 ± 0.06,105.44 ± 9.82,3.51 ± 0.33,308.36 ± 16.17 U/mL. The MDA and SOD factors in the liver were restored to 0.71 ± 0.33 nmol/mL and 77.40 ± 9.88 U/mL, which were significantly different from the model group ( P < 0.05 ). In summary, the silkworm pupa peptide prepared by the double response surface method not only optimizes the process flow but also improves its antioxidant activity and can exert antioxidant activity in vitro and in vivo, which provides an experimental basis for the development and utilization of silkworm pupa protein peptides.
