Composition of solvent-fractionated rice bran oil

Rice bran oil was acetone fractionated at low temperature. Two methods, independent fractionation (-8, -14 and -35C) and sequential fractionation (0, -8 and -14C), were compared for the preparation of triacylglycerol (TG) fraction-enriched unsaturated fatty acids (UFAs). Among all fractions obtained from both methods, the liquid fraction from independent fractionation at -35C referred to as -35L was the best (89.6%) compared to other procedures used for enrichment of UFAs. However, when weight yield was considered, the largest amount of UFAs was obtained from the liquid fraction at 0C (0L) from sequential fractionation. After sequential fractionation at 0C, 87.5 wt % was recovered in the liquid fraction that contained 71.5% total UFAs. In addition, as the fractionation temperature was lowered, the content (%) of gamma-oryzanol in the liquid fractions was increased gradually. Reversed-phase high-performance liquid chromatography showed four regions based on the partition number of TG molecules of the separated peaks.