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

摘要

The current study investigated the comparison of enzymatic (phospholipase A1)degumming of crude rice bran oil on the mechanical-stirring and ultrasonic-assistedsystems. 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℃) was studied for mechanical-stirring enzymatic degumming process. Themaximum removal of phospholipids by mechanical-stirring enzymatic degummingwas observed with 3% water and 3.6 ml/kg of the enzyme at 40℃. Using the optimizedlevels of water, enzyme, and temperature, enzymatic degumming was carriedout under ultrasonication with different power levels (20%, 30%, 40%, and 50%). Theultrasonic power level of 325 W (50% amplitude) showed maximum phospholipidremoval with lesser time. Compared to mechanical-stirring enzymatic degumming,ultrasonic-assisted enzymatic degumming had a higher cavitational yield, leading toenhanced enzyme activity and maximum phospholipids removal. The studies on thephysicochemical properties showed that ultrasonic-assisted enzymatic degumminginduced hydrolytic rancidity and primary oil oxidation due to the cavitation effect. Asa result, more emphasis should be paid to the oxidative stability of the oil in futureapplications.