Study on Extraction of Polyphenols from Longan Seed by Response Surface Analysis

The polyphenols were extracted from the longan by ethanol. On the basis of single-factor experiments,the optimal extraction conditions were obtained by using the response surface analysis. The results showed that ethanol concentration reached a significant level on the yield ( P 0. 01) ,extraction time was significant on yield ( P 0. 05) ,while the extraction temperature and solid to liquid ratio was not significant on the yield,the four factors primary and secondary relationship was ethanol concentration,extraction time, extraction temperature,solid to liquid ratio. The practical extraction rate could be well in accordance with the prediction value of the regression model obtained by response surface analysis. And the optimum extraction were as follow: extraction time was 106 min,ethanol concentration was 58 % ,extraction temperature was 64 ℃,liquid rateo was 1∶ 9,and the yield was 42. 690 mg/g.