Optimization of ultrasound-assisted extraction of polyphenols from kiwifruit peel using response surface methodology

The polyphenol was extracted by ultrasonic assisted method, and the extraction process was optimized by response surface method.On the basis of single factor experiment, the response surface experiment with four factors and three levels was used to study the effect of ultrasonic power, extraction time, extraction temperature and liquid-solid ratio on the extraction rate of polyphenols.The results showed that the optimal extraction conditions were ultrasonic powder of 384.00 W, extraction time of30.00 min, extraction temperature of 65.00 ℃ and liquid to solid ratio of 23.00 m L/g, under these conditions, the experimental TPY was ( 28.10 ± 0.38) mg GAE/g, which was well matched with the predicted values ( 28.14 mg GAE/g) . In addition, the antioxidative activity of the polyphenols was investigated by measuring its scavenging ability on 1, 1-diphenyl-2-picryl-hydrazyl ( DPPH) in vitro, and EC50 value of extracted kiwifruit peel polyphenols was 0.13 mg/m L.The results indicated that the extracted polyphenols had good antioxidant activity.