Study on extraction of total flavonoids from citrus peel with microwave

The total flavonoids in citrus peel were extracted by microwave treatment. Ultraviolet spectrophotometry method was used to determine the content of flavonoids in extracting solution of citrus peel. The effects of average microwave output power, ratio of solvent to material, treatment time, pH value and extraction frequency on the extraction yield were investigated. And the orthogonal test design L16(44) was used to optimize the conditions of microwave treatment. The optimum conditions of microwave treatment were as follows: microwave output power 400 W, extraction circle 180 seconds, ratio of solvent to material by weight 50∶1, pH value 5. Under the best extraction conditions whose frequency of extraction was 2, the total content of flavonoids was 3.37%. The extraction time of microwave was 1/20 of supersonic extraction and extraction rate of microwave was higher than supersonic.