Optimization of ultrasonic-assisted extraction conditions of polyphenol from Picea koraiensis Nakai by response surface methodology

The ultrasonic- assisted extraction conditions of polyphenol from Picea koraiensis were optimized by response surface methodology.Based on single factor test, a 3- factor, 3- level Box- Behnken experimental was adopted, including dependent variables ( ratio of material to liquid, ultrasonic wave power and extraction time) and independent variable ( yield of polyphenols) .The results showed that the regression model fit well with experimental data.The optimum conditions were ratio of material to liquid 1∶33, ultrasonic wave power 301W, extraction time 2.4h, ethanol concentration 40%, extraction temperature 60℃. Under these conditions, the yield of polyphenol was 18.92%.