Comparison of extraction technology of total flavonoids from citrus peels by two microwave extraction systems

The microwave chemical reaction system and microwave digested/extraction system for total flavonoids(TF) from citrus peels were optimized and compared.The solvent quantum to citrus peel(g:mL),ethanol content(%),extraction time(min),microwave power(W)(in microwave chemical reaction system) or extraction temperature(℃)(in microwave digested/extraction system) were reviewed using the L9(34) orthogonal design.The extraction conditions of the microwave extraction methods were both optimized.The optimum ethanol extraction process conditions were as follows:adding 30 fold of 70% ethanol,extracting for 2.0 min under 240 W power in microwave chemical reaction system,the extraction yield was 4.72 mg/g;adding 20 fold of 70% ethanol,extracting for 3.0 min at 160 ℃ in microwave digested/extraction system with extraction yield 9.15 mg/g.As a result,the extraction yield for TF from citrus peels was almost two times than the former.The reason was discussed.Three different samples of citrus peels were determined and compared with the optimal extraction conditions using these two microwave methods,respectively.The microwave digested/extraction system can be used in rapidly and simply extracting active components from natural products,for it has higher extraction yield than the general microwave-assisted extraction.