Optimization of ultrasonic assisted alkali peeling process of walnut kernel

This study took walnut kernel as raw material and the technology of ultrasonic assisted alkali peeling was adopted.On the basis of single factor tests, the concentration of Na OH solution, ultrasonic temperature, alkali hot time and ultrasonic power were selected as the test factors, and peeling rate as examine index.The optimum process of walnut kernel peeling was optimized by using the response surface method. The test results showed that when the concentration of Na OH solution was 0.8%, ultrasonic temperature was 64 ℃, alkaline hot time was 4.5 min, ultrasonic power was 380 W, the average peeling rate of three tests was 5.46% ± 0.02%, and that the walnut peeling effect was the best, almost all of the skin could fall off after rinsing with water and the walnut had crisp texture and white color and no alkali flavor, which indicated that the optimized process was feasible.