Research On Enzymolysis Optimization And Decoloring Process Of The Antioxidant Silkworm Chrysalis Protein

Abstract:Silkworm chrysalis is considered as a new food resource approved by The Ministry of Health of the People’s Republic of China. It has been indicated that the protein hydrolysate of Silkworm chrysalis has prominent antioxidant activity. However, the unwelcome browning reaction in the protein hydrolysate greatly limited its further processing in food manufacture. To solve this problem, a purification process was established to remove the color without influencing the anti-oxidative property of the hydrolysate. More precisely, this dissertation included three aspects:1) Protein hydrolysis. With papain as hydrolase, the parameters for hydrolysis was evaluated by DPPH inhibition rate and optimized via response surface methodology. The optimized conditions for hydrolysis are:reaction temperature 49℃, pH 7.0, substrate concentration 2.1%; enzyme concentration 2.0%. With the optimized conditions, the DPPH clear rate of the hydrolysate can achieve 84.0%.2) Decolourization. With the mixed adsorbents composed by activated clay, alkaline Ca-bentonite, and bentonite, the parameters of decolourization process were investigated by decolourization rate and DPPH inhibition rate through response surface methodology. The optimized conditions are:amount of adsorbent 1.9%; concentration of hydrolysate solution 9.61 mg-mL"1; pH 7.2; temperature 60℃; stirring speed 150 rpm; stirring time 1h. Under the optimized conditions, the DPPH inhibition rate is 84.5% and the decolourization ratio is 94.5%.3) Scale-up. On the basis of the optimized parameters obtained in lab trial, a 20-fold scale-up experiment was conducted as a preliminary test for industrial application.