Abstract: Based on single factor test,a 3-factor,3-level Box-Behnken experimental was adopted,including dependent variables (extraction time,liquid-solid ratio and ultrasonic wave power) and independent variable (polyphenol yield).The optimum conditions of ultrasonic-assisted extraction technology for polyphenol from Litsea coreana were determined by using response surface method.The results showed that the regression model fitted well with experimental data.The optimum conditions were 5 g samples,extraction time 22 min,liquid-solid ratio 21:1,ultrasonic wave power 300 W.Under these conditions,the polyphenol yield was 3.76%.

Key words: Litsea coreana, polyphenol, ultrasonic-assisted extraction, response surface optimization