Changes in physicochemical characteristics of rice bran oil during mechanical‐stirring and ultrasonic‐assisted enzymatic degumming

Abstract The current study investigated the comparison of enzymatic (phospholipase A1) degumming of crude rice bran oil on the mechanical‐stirring and ultrasonic‐assisted systems. The effect of process parameters like, water (1.5%, 2%, 2.5%, 3%, and 3.5%) and enzyme dosage (1.2, 1.8, 2.4, 3, and 3.6 ml/kg) and temperature (35, 40, 45, 50, and 55°C) was studied for mechanical‐stirring enzymatic degumming process. The maximum removal of phospholipids by mechanical‐stirring enzymatic degumming was observed with 3% water and 3.6 ml/kg of the enzyme at 40°C. Using the optimized levels of water, enzyme, and temperature, enzymatic degumming was carried out under ultrasonication with different power levels (20%, 30%, 40%, and 50%). The ultrasonic power level of 325 W (50% amplitude) showed maximum phospholipid removal with lesser time. Compared to mechanical‐stirring enzymatic degumming, ultrasonic‐assisted enzymatic degumming had a higher cavitational yield, leading to enhanced enzyme activity and maximum phospholipids removal. The studies on the physicochemical properties showed that ultrasonic‐assisted enzymatic degumming induced hydrolytic rancidity and primary oil oxidation due to the cavitation effect. As a result, more emphasis should be paid to the oxidative stability of the oil in future applications. Practical Applications Degumming is the preliminary and important step in the refining of oil. Chemical degumming approaches don't remove maximum phospholipids and also cause higher neutralized oil loss. Enzymatic degumming results in maximum removal of phospholipids from the oil but also takes a long time to reduce the phosphorus content below the desired level. The application of ultrasound on enzymatic degumming effectively increases the reaction rate in lesser time. The ultrasonic‐assisted enzymatic degumming also results in better oil quality and physio‐chemical parameters. So, ultrasound can be effectively applied to enzymatic degumming of rice bran oil.