An Innovative Deacidification Approach for Producing Partial Glycerides-Free Rice Bran Oil

In the present study, an innovative deacidification approach has been established for producing partial glycerides-free rice bran oil (RBO). Partial glycerides (monoacylglycerol (MAG), diacylglycerol (DAG)) in high-acid RBO were firstly hydrolyzed to FAs by immobilized MAG and DAG lipase SMG1-F278N-catalyzed hydrolysis followed by deacidification by immobilized SMG1-F278N-catalyzed esterification. Deacidification efficiency as high as 99.79% was achieved under the optimal conditions. During deacidification, the immobilized SMG1-F278N exhibited excellent reusability. It could be used for 20 cycles without significant loss in activity. After purification by molecular distillation at lower temperature (120 °C), a final product with 99.86% TAG, 0.05% DAG, and 0.09% FAs was obtained. Compared with the previous methods, the new process could effectively remove almost all FAs and partial glycerides. Removal of partial glycerides would favor the downstream refining process and reduce the risk of formation of glycidyl esters during the following deodorization process. Moreover, the by-product (FA ethyl esters) produced during deacidification could be used as biodiesel or as intermediates for the synthesis of other lipids.