Optimization of ethanol extraction technique of polyphenols from rice bran by response surface methodology

The aim of this paper was to optimize the extraction technique of polyphenols from rice bran by ethanol extraction.Based on the single factor experimental analysis, central composite design of response surface analysis was used to explore the optimal processing conditions to extract polyphenols from rice bran including the concentration of ethanol, extraction temperature and solid to liquid ratio.The results showed that the optimal extraction conditions were the concentration of ethanol57%, extraction temperature of 65 ℃, solid to liquid ratio of 1∶ 25 ( g/m L) , extraction duration of 2 h and extraction times of2 times. Under these conditions, the highest yield of polyphenols from defatted rice bran was ( 4.75 ± 0.16) mg/g, the predicted value of the regression equation was 4.82 mg/g, and the relative error was about 1.47%.In conclusion, the optimized extraction process was reliable and could be utilized to develop products based on rice bran.