Composition, industrial processing and applications of rice bran γ-oryzanol

Rice bran oil (RBO) (20–25 wt% in rice bran) is a unique rich source of commercially-important bioactive phytochemicals, most of them of interest in nutrition, pharmacy and cosmetics. The unsaponifiable constituents of RBO include mainly tocols (vitamin E, 0.10–0.14%) and γ-oryzanol (esters of trans-ferulic acid with sterols and triterpenic alcohols, 0.9–2.9%). The following topics concerning γ-oryzanol are reviewed: analytical methods for characterisation and determination; influence of genetic and environmental factors on the composition of rice bran; extraction approaches, including supercritical CO2 and subcritical water; and biomedical and industrial applications, including food and pharmaceuticals. Concentration ranges of γ-oryzanol, tocopherols and tocotrienols found in rice bran and RBO from different varieties and geographical areas are summarised. This review focuses on the 2003–2008 period, where an average of 13–14 references per year were published; however, some relevant work reported during the 1998–2002 period is also briefly commented upon.