Determination of γ-Oryzanols in Rice Bran

Abstract

The amount of γ-oryzanol in rice bran and its adsorption coefficient (K) can be determined bysolving two simultaneous equations. When di-isopropyl ether is the extraction solvent, the amount ofγ-oryzanol in rice bran is 3.48 mg/g rice bran (dry weight basis), which is very close to the soxhletextraction method (3.67 mg/g rice bran). The adsorption coefficient of γ-oryzanol determined by usingdi-isopropyl ether is 8.48. Due to their high polarities, the amounts of γ-oryzanol are slightly higherthan the classical method when ethanol and iso-propanol are used as the extraction solvents. Thehigher values are not unexpected because ethanol or iso-propanol may extract γ-oryzanol from othercomplex lipids as well as from most part of rice bran.

The proposed method for determination of γ-oryzanol, however, is rapid and economical.

Keywords : γ-Oryzanol / Rice Bran / Adsorption Coefficient / Acid Value