Fatty acid distillation residues from rice oil bran refining as a source of phytochemicals

Abstract

SummaryThe aim of this work was to develop an extraction method to recover γ‐oryzanol and tocopherols from the distillation residue of the fatty acids generated during the neutralisation step of the rice bran oil refining process. The phytochemicals extraction was performed with different solvents (chloroform, methanol, methyl ethyl ketone and acetone) at a ratio of 10:1 v/w (solvent: sample), by agitating the mixture for 10 min at room temperature (20 °C ± 2 °C), then stored at −18 °C for 15 h. The γ‐oryzanol and tocopherol content in the extracted fractions were concentrated and quantified using reverse phase high‐performance liquid chromatography coupled with UV–vis and fluorescence detector, respectively. It was observed that only one step of extraction with methanol resulted in an increased concentration of tocopherols for about six times, with a recovery of 51.50%. However, using two stages of extraction, the mixture of methanol and methyl ethyl ketone (1:1, v/v) allowed the recovery of 92.15% of tocopherols and 84.12% of γ‐oryzanol, increasing the initial concentration of these phytochemicals in about three times. These results show that there is a great possibility of these phytochemicals recovery from the distillation residue from fatty acid recovery.