Supercritical fluid extraction (SFE) of rice bran oil to obtain fractions enriched with tocopherols and tocotrienols

Parboiled rice bran oil was obtained with supercritical CO2 at temperatures and pressures varying from 25 to 60ºC and from 150 to 250 bar, respectively. This study was divided into two different parts: initially, the experiments were carried out with one separation step. In the second part, experiments were performed with two separators in series. The temperatures and the pressures of the first separator were 25 and 40ºC, and 100 and 150 bar. The second separator was maintained at 2ºC and 25bar. This procedure results in the precipitation of rice bran oil with different concentrations of tocols in the first and second separators. The extracts obtained were analyzed by HPLC to verify the presence of tocopherols and tocotrienols. Unlike other vegetable oils, rice bran oil contains a larger amount of tocotrienols, specially gamma-tocotrienol, than of tocopherols. Finally the extraction curves were modeled by Sovová's method