Novel fractionation method for squalene and phytosterols contained in the deodorization distillate of rice bran oil

Abstract

Since deodorization distillate, a by-product of rice bran oil production, contains squalene (ca. 8%) and phytosterols (ca. 4%) as unsaponifiable components, the concentration of those materials for their use in the cosmetics and food industries is desirable. In the present work, a novel fractionation method of concentrating squalene and phytosterols from deodorization distillate or the unsaponifiable components of the deodorization distillate without oxidative deterioration was examined. Supercritical fluid extraction (SFE) with supercritical carbon dioxide was investigated under the following conditions: temperature, 30 degrees C; pressure, 100 kg/cm(2); flow rate of carbon dioxide, 7 mL/min. Under these conditions, squalene was effectively concentrated to 25% with nearly quantitative recovery, and then a more highly concentrated squalene (ca. 50% purity) was obtained by using a supercritical fluid chromatography (SFC) with silica gel packed into the extraction vessel. In addition, squalene with ca. 68% purity could be obtained by repeating the SFC twice. After the saponification of the deodorization distillate, followed by solvent fractionation with hexane, highly purified phytosterols (97% purity) could be obtained, and highly purified squalene (81% and 100% purity) could be also obtained by using SFC combined with the solvent fractionation technique for the unsaponifiable materials. Therefore, it is considered that the present fractionation method combined with SFC and solvent fractionation is an effective means of concentrating squalene and phytosterols.