Characterization of proteins in Soy Sauce Residue and its hydrolysis by enzymes

摘要

To reveal the biochemical characteristics, proteins in Soy Sauce Residues (SSR) was prepared by centrifugation in combination with lyophilization. The proteins in SSR were identified by SDS-PAGE and MALDI-TOF-MS. Results showed that acidic polypeptides (Ala, A2, Alb, A4) and basic polypeptides (B2, Bla, Blb, B3, B4) of glycinin from soybean proteins were the predominant proteins in SSR. In order to make better use of the residual protein in SSR, the optimal conditions of the cellulase and alcalase were analyzed. The optimal conditions for two-step enzymatic hydrolysis of soy sauce residue were as follows: pre-treatment by 0.01% Celluclast 1.5 L at pH 5.0, 55°C for 1 h, together with treatment by 0.05% Alacase 2.4 L at pH 8.0, 65°C for 2 h. The hydrolysis yield of protein (Soluble nitrogen index) could reach 62.45%. The analysis of the crude protein dissolution rate indicated that enzyme combinations could hydrolyze the proteins of SSR effectively.