Preferential extractability of γ-oryzanol from dried soapstock using different solvents

Abstract

Background: γ-Oryzanol from rice bran has lately gained potential importance because of its proven health benefits. Thus the extractability of γ-oryzanol from the soapstock of crude rice bran oil is important from the perspective of future large-scale production, which would give value addition to this by-product obtained from the rice bran oil industry. The aim of the present study was to investigate the extraction of γ-oryzanol from the drum-dried soapstock of rice bran oil using various solvents. Results: It was found that γ-oryzanol could be extracted most effectively using ethyl acetate, followed by dichloromethane and ethyl methyl ketone. All components of γ-oryzanol have an alcohol group in the ferulate portion giving rise to relatively high polarity, thereby increasing the extraction in more polar solvents efficiently. Ethyl acetate showed maximum extractability of γ-oryzanol by the Soxhlet method. To quantify γ-oryzanol, reverse phase high-performance liquid chromatography (RP-HPLC) was used for fingerprinting the γ-oryzanol analogues with respect to standard γ-oryzanol. Conclusion: A new RP-HPLC method for determining the individual components of γ-oryzanol has been reported that can be used for performing an online characterisation of γ-oryzanol analogues by liquid chromatography/mass spectrometry.