Deacidification of rice bran oil using a deep eutectic solvent

Abstract

The liquid-liquid extraction (LLE) will be applied in this study using a deep eutectic solvent (DES) of choline chloride and ethylene glycol with a 1:2 molar ratio. The LLE process will compare the results of removing free fatty acids (FFAs) between single and multiple extractions. Rice bran oil (RBO) with various initial FFAs contents (5%, 10%, 20%, 30%, 40%, and 60%, w/w) and γ -oryzanol (2%, w/w) are used in this study. Deacidification is carried out by mixing RBO with a certain level of FFAs and γ -oryzanol, a volume ratio of RBO: solvent (DES) = 1:2, and total extraction time in multiple LLE was 1200 min. (240 min./stage x 5 stage). It was obtained that the removal of FFAs in the single LLE are 10.04%, 23.28%, 13.43%, 17.55%, and 17.49%, respectively, while in the multiple LLE are 48.64%, 60.37%, 63.13%, 63.15%, and 41.79%, respectively, for RBO with an initial FFAs content of 5%, 10%, 20%, 30%, 40% and 60%, respectively. The losses of γ-oryzanol in the single LLE are 48.32%, 61.26%, 73.32%, 74.22%, and 89.59%, respectively, while in the multiple LLE are 87.16%, 95.58%, 99.14%, 99.77%, and 99.77%, respectively, for RBO with an initial FFAs content of 5%, 10%, 20%, 30%, 40% and 60%, respectively. Deacidification of RBO using DES in the multiple LLE removed FFAs 3.63 times higher than that in the single LLE. However, the losses of γ-oryzanol increased in the multiple LLE which is 1.43 times higher than that in the single LLE.