Optimization of electrochemical treatment of oil‐containing walnut emulsion by response surface contour stacking

Using cold-pressed walnut cake as a raw material, an oil-containing walnut emulsion is prepared and processed in an electrochemical reaction system. The electrochemical treatment conditions are optimized via the superposition of contour lines on the response surface. Under the optimal conditions of 120 min at a temperature of 60°C and a current density of 10 mA/cm2, the iodine value is shown to decrease by 28.12%, the nitrogen solubility index to increase by 9.16%, the content of linoleic acid in unsaturated fatty acids to decrease by 16.71%, and the linolenic acid to decrease by 7.81%. After storage at 25°C for 24 weeks, the peroxide value is only 5.57 meq O2/kg oil. This demonstrates that the solubility and oxidation stability of the oil-containing walnut powder have been improved by the electrochemical treatment, thereby prolonging the shelf life of the walnut powder, and providing a theoretical basis for the market application and industrial promotion of walnut cake. Practical applications In this paper, the electrochemical treatment of oil-containing walnut emulsion is used to improve the solubility of walnut flour and enhance its antioxidant activity. The electrochemical conditions are optimized via the superposition of the response surface contours. During the electrochemical process, the product quality is improved, thus providing a useful outcome for the food industry.