The concentration of tocols from rice bran oil deodorizer distillate using solvent

Abstract

Tocols (tocopherols + tocotrienols) have been concentrated efficiently from rice bran oil (RBO) deodorizer distillate using solvent at low temperature. The levels of total tocols, total tocopherols, and total tocotrienols in RBO deodorizer distillate (starting material) were 31.5, 14.9, and 16.6 mg/g, respectively. Nine different solvents were tested, and acetonitrile was selected as the optimal solvent for concentrating tocols from the RBO deodorizer distillate. There was a significant (p < 0.05) increase in the tocol level of the liquid fractions with decreasing temperature, for incubation temperatures up to -20 degrees C. In addition, significant differences (p < 0.05) were observed in the relative percentages of alpha-tocopherol, gamma-tocopherol, alpha-tocotrienol, and gamma-tocotrienol between the raw sample and liquid fractions obtained at different temperatures using acetonitrile as the solvent. The concentration of the tocols from the RBO deodorizer distillate was temperature dependent, and a maximum of 89.9 mg/g was attained in the liquid fraction at - 40 degrees C. The relative percentage of tocotrienol homologs in the liquid fraction obtained at - 40 degrees C was approximately 80%. With acetonitrile as the solvent, the optimal temperature for concentrating the tocols from RBO deodorizer distillate was -20 degrees C when yield was considered.