Study on the microwave-assisted extraction and antioxidant properities of total flavonoids from Zixing citrus peel

Orthogonal experimental design was employed to study the microwave-assisted extraction process of total flavonoids from the citrus peel of Zixing city.The antioxidant prosperities of total flavonoids extracts were also discussed.The optimum conditions for extracting total flavonoids from the citrus peel of Zixing city were:ethanol concentration 70%,solid to liquid ratio 1 ∶ 40(g/mL),microwave power 600W,extraction temperature 70℃ and extraction time 20 min.Under these optimum conditions,the extraction efficiency of total flavonoids was as high as 21.11mg/g.Solid to liquid ratio had the most important effect on the extraction,followed by ethanol concentration,extraction temperature and microwave power.The total flavonoids from citrus peel exhibited an obvious scavenging effect on free radicals.The antioxidant activity of total flavonoids was a dose-dependent in the certain concentration range.Based on these results,it can be concluded that the flavonoids extracted from citrus peel had strong antioxidant activities,a good antioxidant ingredient in functional foods.The extraction method was suitable for large-quantity industrial production of citrus peel total flavonoids.