Microwave-assisted extraction technique of apple polyphenols in apple pomace

In order to make full use of agricultural waste materials——apple pomace, and increase the extraction rate of apple polyphenols from apple pomace. Microwave extraction technique of apple polyphenols from apple pomace was studied by quadratic general spinnins design, the optimum conditions were determined. Results showed that the volume of ethanol had a very significant effect on the extraction rate of apple polyphenols. Microwave radiation, ethanol concentration and the interaction between extraction time and microwave radiation also had significant effects on the extraction rate. Extraction time had no significant effect on the extraction rate. The optimum conditions are extraction time 60 s, microwave radiation 750 W, ethanol concentration 60%, ethanol volume 25 mL(the ratio of material to liquid is 1∶50); the extraction rate of apple polyphenols is 11.93 mg/g(DW) in theory(retest result is 11.41 mg/g), which is higher than that extraction methods of refluxing and ultrasonic.