Optimization of Ethanol Extraction of Rutin from of Chinese Jujube Residue by Response Surface Methodology

The effects of ethanol concentration,temperature,extraction time and ratio of material to liquid on the extraction of rutin from Chinese jujube residue were investigated.Subsequently,a central composite design leading to 17 experiments of the other three variables expect ratio of material to liquid at three levels combined with response surface methodology was employed to maximize rutin extraction.The optimum extraction conditions were determined as follows:ratio of liquid to solid 1:40(m/V),ethanol concentration 69%,and temperature 70 ℃ for an extraction duration of 8.5 h,and under these conditions,the maximum extraction rate of 155.46 mg/100 g was obtained.