Extraction of rice bran oil using microwave-assisted extraction and green solvents

Abstract

Rice bran oil (RBO) is a healthy vegetable oil made from rice bran. A microwave- assisted extraction method (MAE) was developed in this work to produce RBO with greater productivity than the conventional method, i.e., solvent extraction (SXE). Furthermore, green solvents such as ethanol and d-limonene were compared as an alternative to the less environmentally friendly n-hexane. An evaluation of energy consumption and raw material costs was conducted using the MAE method. The 30 mesh bran was stabilized in the oven for 30 min at 100°C followed by MAE extraction, which was performed by mixing 50 g of bran and 300 ml of solvents in a microwave oven set to 450 watts and 60°C for 60 min. Filter paper was used to separate the extract from the bran, and the oil was recovered by solvent evaporation. Finally, the oil was weighed and the fatty acid composition was determined by GC-MS. The results showed that the yield of RBO using d-limonene and MAE was the largest (24.64%) as well as consuming less energy (95Wh/gr oil). Linoleic acid was only found in the extraction with d-limonene and EtOH was successful in obtaining longer-chain saturated fatty acids.