Orthogonal optimization for tea polyphenols from Green Tea based on multi-frequency ultrasound-assisted extraction

The extraction technology of tea polyphenols from Green Tea was studied and optimized. The effect of extracting tea polyphenols on different operating parameters, such as extraction time, extraction temperature, liquid /solid ratio, rate of circulation, ultrasonic power and frequency were investigated, in which green tea was selected as the raw material. Orthogonal array design was elected by optimization of the operating parameters using.The optimal extraction technology was determined as follows: one extraction cycle at 65℃ for 20 min with the ratio of solid to liquid of 1 ∶ 70 g /mL. And the ultrasonic frequency was 28, 33, 40 and 60 kHz respectively, while ultrasonic power was 200 W, the circulation velocity was 1200 r /min. The extraction rate of tea polyphenols was25.69%, compared with the traditional extraction method was improved by 43.68%.