Optimization of aqueous enzymatic process of peanut with residual oil in aqueous phase by response surface methodology

Aqueous enzymatic process is a technology for extracting peanut oil and protein simultaneously. However, peanut oil dispersing in aqueous phase stably is not beneficial for the improvement of the oil yield. In this study, the micromorphology of the aqueous phase system was observed by CLSM and biomicroscope through wet grinding of peanuts, and the relationship between aqueous phase oil residual rate and oil droplet distribution were analyzed under different grinding time. The results showed that the aqueous phase obtained by aqueous enzymatic process was a high protein and low oil content system. When the grinding time was 120 s, the lowest aqueous phase residual oil rate was obtained and the content was 10.78%, and the oil droplets in the aqueous phase had the smallest number. Single factor experiment was designed to study the effect of enzymatic hydrolysis conditions on the aqueous phase residual oil rate, and the optimal conditions were obtained through response surface methodology. The optimal conditions were as follows:enzymatic hydrolysis time 1.37 h, temperature 47.92℃, enzyme concentration 1.25%, and liquid-solid ratio 4.89:1 mL/g. Under these conditions, the aqueous phase residual oil rate was 8.79%±0.03%, which had no significant difference with the predicted value of 8.82%. This result would provide a theoretical basis for the improvement of oil yield by aqueous enzymatic process.