Simplified Physical Upgrading of High-Acid Adlay Bran Ethanol Extracts by Supercritical CO2

Abstract

Abstract Deacidification is one of the key steps in oil-refining processes. This study reported a simple approach for upgrading high-acid adlay bran oil by supercritical carbon dioxide (SC-CO2) extraction. The high-acid adlay bran oil was obtained by three-stage countercurrent ethanol extraction of adlay bran, with high free fatty acids (34 % FFAs). The FFA content in adlay bran oil reduced to 10.6 % by SC-CO2 extraction under optimized conditions. Interestingly, the SC-CO2 deacidification process also markedly reduced oil color value from 11.5 (Red) to 0.3 (Red) and acetone-insoluble matters in the oil from 1.56 % to 0.17 %. The results indicated solvent extraction combined with SC-CO2 deacidification method could be a feasible approach to significantly upgrade high-acid adlay bran oil and simplify refining process of adlay bran oil.