Concentration of tocopherols by supercritical carbon dioxide with cosolvents

In order to optimize the conditions for enrichment of tocopherols, tocopherol extraction from chemically modified rapeseed deodorizer distillate (RDD) at three levels (2%, 4%, and 6%) of each cosolvent (methanol, ethanol, and mixed ethanol) was carried out by using supercritical carbon dioxide (SC-CO2). After chemical modification, the fatty acid methyl esters (FAME) in RDD were produced and showed improved solubility in SC-CO2. Since FAME were more volatile, they were extracted preferentially over tocopherols and other higher molecular weight compounds. Two steps were applied in the SC-CO2 extraction. First, the FAME mixture was extracted under 120 bar until the weight of extracts did not increase anymore, and then, tocopherols were concentrated under 250 bar. Second, the concentrates from the first step under 250 bar were esterified and then extracted again under 120 bar until the weight of extracts did not increase anymore. Different cosolvents (methanol, ethanol, mixed ethanol) were used for tocopherol isolation under 250 bar in the second step. Tocopherol content, tocopherol recovery and the weight of target extract (those extracts with a concentration of tocopherols above 40%) increased while the extraction time decreased.