Preliminary study on protein isolation process of walnut dregs by single factor experiments and response surface method

The production of protein by alkali-solution and acid-isolation method will lead to the increase of salt in the feed liquid and affect its quality. In order to simplify the production of protein by the alkali acid precipitation process and obtain protein with high content and quality, the cation exchange resin was used to separate the walnut dreg protein. The desalination rate, protein content and recovery rate were used as indicators. Single factor experiments and response surface method were used to optimize the time used to isolate the protein from the cation exchange resin, the speed and temperature of the water bath shaker. Our results showed that the optimal time was determined at 62 min; the optimal speed of the water bath shaker was 120 rpm, and the optimal temperature was 49 °C. Under these conditions, the optimal protein recovery was 95.22% and the optimal protein content was 78.12%.