Response Surface Optimization of Proteolytic Process and Protein Peptide Composition Analysis of Antarctic Krill

Abstract:

The amino nitrogen content in the antarctic krill hydrolysate was used as an indicator. The hydrolysis results of trypsin, papain, alkaline protease, pepsin, flavor protease and subtilisin were evaluated by formaldehyde potentiometric titration. The enzymatic hydrolysis of Antarctic krill protein was optimized for the enzymatic hydrolysis of Antarctic krill. On the basis of single factor experiment, the amino acid content in the enzymatic hydrolysate was used as the response value, and the enzymatic hydrolysis temperature, time and pH were selected as independent variables. The three-factor and three-level Box-Bohnken response surface analysis method was used to screen the bio-enzymatic solution. The process is optimized. Based on the optimized enzymatic hydrolysis process, the molecular weight distribution range of Antarctic krill enzymatic protein peptide and Antarctic krill protein was analyzed by SDS-PAGE gel electrophoresis. The results showed that trypsin was the ideal protease for enzymatic hydrolysis of Antarctic krill protein; the response surface analysis method was used to establish a quadratic multiple regression equation: Y=51.07-0.83A+1.72B-2.06C+0.25AC+1.15BC-3.06A2-2.77B2-3.69C2, the model p<0.0001, and the missing term p>0.05, indicating that the model is extremely significant and stable, the best condition obtained by model analysis is: Enzymatic hydrolysis temperature was 44.48 ℃, the enzymatic hydrolysis time was 8.52 h, and the pH was 7.88. Considering the practical application feasibility, the amino nitrogen content of the experiment was 50.96±1.07 mg/g under the conditions of enzymatic hydrolysis temperature of 45.0 ℃, hydrolysis time of 8.5 h and pH 7.9, which is basically consistent with the theoretical prediction value of 51.57 mg/g. The molecular weight of Antarctic krill protein was over 15 ku by electrophoresis analysis, and the main molecular weight range was 15 ku~45 ku. The molecular weight of trypsin peptide was below 25 ku, and the main molecular weight distribution was below 5 ku.