Changes in nutraceutical lipid components of rice at different degrees of millingThe concentrations of several nutraceutical lipid components [tocol (i.e. tocopherol 1 tocotrienol) phytosterol, g-oryzanol, octacosanol, and squalene] in milled rice and brown rice were determined. The lipid content decreased significantly (p ,0.05) as the degree of milling increased, as did the total tocol content. Significant differences (p ,0.05) were observed in the relative percentages of a-tocopherol, a-tocotrienol, and g-tocotrienol in brown rice and milled rice. b-Sitosterol was the most abundant sterol, representing 50-56% of the total sterol content of all samples analyzed. There were no significant differences in the relative percentages of the sterol isomers as the degree of milling increased. The concentrations of g-oryzanol, squalene, and octacosanol in rice decreased significantly (p ,0.05) as the degree of milling increased.

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An efficient process was developed for enrichment of tocols from rice germ oil (RGO) using supercritical carbon dioxide (SC-CO 2 ). Tocols were efficiently enriched in residue by removal of fatty acid methyl ester from the esterified RGO using SC-CO 2 . The enrichment of tocols was carried out at an operating pressure of 12.4-15.8 MPa, an operating temperature of 40-60°C and a carbon dioxide flow rate of 5.0 L min )1 . The combination of 13.8 MPa pressure and 60°C temperature was selected as the most suitable for efficient enrichment of tocols. The level of tocols (1270 mg ⁄ 100 g) in the residue obtained at these operating conditions was six times higher than the tocols level (192 mg ⁄ 100 g) of the starting material, namely esterified RGO. There were no significant differences in relative percentages of tocols homologues between esterified RGO and the residue obtained by SC-CO 2 extraction.