ABSTRACT
d-Limonene, a safe agricultural by-product, was used to extract rice bran oil and compared against hexane, a petroleum product widely used as a solvent for extracting edible oil. The yield of crude rice bran oils extracted with both solvents in percentage by weight was obtained. The quality of crude rice bran oil was analyzed. The yield and quality of crude rice bran oil from the limonene-based solvent extraction were almost equivalent to those from the hexane-based operation. The optimum solvent-to-rice bran ratio and extraction time required for d-limonene extraction of oil, based primarily on crude rice bran oil yield, have been determined to be 5:1 and 0.5 hr, respectively. Despite the absence of antioxidants during the limonene recovery step with vacuum evaporation, the quantity of the oxidation products in the recovered limonene was <1% (wt) of the original limonene solvent. The application of d-limonene solvent as an alternative to hexane in edible oil extraction could potentially eliminate the safety, environmental, and health issues associated with the use of hexane.
