Response Surface Methodology for Optimization of Enzymatic Preparation of Umami Peptides from Mytilus edulis

For the sake of establishing the technology of enzymatic hydrolysis of Mytilus edulis to prepare umami peptides, improve the added value of Mytilus edulis and develop its application potential. In this paper, Mytilus edulis meat was used as raw material, and hydrolysis degree and sensory score are used as indicators. From the five proteases tested, a composite protease was selected as a suitable hydrolase for hydrolyzing Mytilus edulis meat to prepare umami peptides. The effects of time, pH, solid-liquid ratio, enzyme dosage and the effect of the temperature on the enzymatic hydrolysis were studied by virtue of single factor experiment to determine the range of enzymatic hydrolysis parameters. Then Plackett- Burman test was used to screen the key influencing factors of enzymatic hydrolysis, and response surface analysis is used to optimize the enzymatic hydrolysis process parameters. The results show that the key influencing factors were pH, enzyme dosage, temperature, and time, and the optimum hydrolysis conditions were time of 3.6 h, pH of 6.3, enzyme dosage of 1120 U / g pro, temperature of 54 ℃, solid-liquid ratio 1:2 g/mL. Under these conditions, the predicted degree of hydrolysis was 44.37%, the sensory score was 5.65, the measured degree of hydrolysis was 44.52% ± 0.66%, and the sensory comprehensive score was 5.62 ± 0.12. T test showed that there was no significant difference between the measured value and the predicted value (P>0.05). Through the enzymatic hydrolysis process established in this paper, delicious hydrolysate can be prepared, which can provide theoretical support for the deep processing of Mytilus edulis.The enzymatic hydrolysate is divided into three components by the membrane separation system, and the umami peptides are mainly concentrated in the components with a relative molecular mass of less than 3 kDa.