Ultrasonic Assisted Aqueous Enzymatic Extraction of Batang Walnut Oil and Its Oxidation Stability

To determine the optimal process for extraction of Batang walnut oil by ultrasonic-assisted aqueous enzymatic methods(pectinase,cellulase,and neutral protease)and the effect of different storage conditions on the oxidation stability of walnut oil,The optimum extraction conditions were obtained by single factor and L₉(3⁴)orthogonal experiment to study the effects of pH value,enzymolysis temperature,enzymolysis time and enzyme dosage on the extraction rate of oil. Using peroxide value and acid value as indicators,the stability of walnut oil under different storage conditions of temperature,light,container materials and antioxidants were studied. The results showed that the optimum extraction process of Batang walnut oil was pH7,the temperature of enzymolysis was 45 ℃,the enzymolysis time was 3.5 h,and the amount of enzyme added was 1.4%. Under these condition,the extraction rate of Batang walnut oil was 78.91%±0.03%. The walnut oil extracted under this condition was filled with iron cans,placed under refrigeration and protected from light,and 0.02% BHT+V_C(mass ratio 1:1)was added as an antioxidant antioxidant,which exhibited better oxidation stability and longer shelf life.