三种广西不同地区绿茶中总黄酮的提取及其抗氧化活性研究

Extraction and antioxidant activities of total flavonoids in green tea from 3 different regions in Guangxi

为研究广西不同地区绿茶的总黄酮提取工艺及其抗氧化活性,该试验以三种广西不同地区(桂北、桂中、桂南)绿茶为原料,采用微波辅助提取法提取总黄酮,在单因素试验的基础上,通过正交试验对三种绿茶总黄酮的微波辅助提取条件进行优化,并根据1,1-二苯基-2-三硝基苯肼(DPPH)、羟基自由基清除能力评价其抗氧化活性。结果表明,桂北地区绿茶最佳提取条件为乙醇体积分数为60%、料液比为1∶60(g∶mL)、微波功率为600 W;桂中地区绿茶最佳提取条件为乙醇体积分数为50%、料液比为1∶50(g∶mL)、微波功率为500 W;桂南地区绿茶最佳提取条件为乙醇体积分数为50%、料液比为1∶50(g∶mL)、微波功率为600 W。在此优化条件下,三种绿茶的总黄酮得率分别为(12.29±0.56)%、(12.51±0.39)%、(14.32±0.42)%。体外抗氧化试验结果表明,三种绿茶总黄酮清除DPPH自由基能力较强,对羟基自由基有一定的清除能力。

In order to study the extraction process and antioxidant activity of total flavonoids in green tea from 3 different regions in Guangxi,using 3 kinds of green tea from different regions of Guangxi(northern Guangxi,central Guangxi,southern Guangxi)as raw materials,the total flavonoids were extracted by microwave-assisted extraction method.On the basis of single factor tests,the microwave-assisted extraction conditions of total flavonoids in 3 kinds of green tea were optimized by orthogonal tests,and their antioxidant activities were evaluated according to 1,1-diphenyl-2-picrylhydrazyl(DPPH)and hydroxyl radicals scavenging ability.The results showed that the optimum extraction conditions of green tea in northern Guangxi was ethanol volume fraction 60%,solid and liquid ratio 1:60(g∶mL),and microwave power 600 W.The optimum extraction conditions of green tea in central Guangxi were ethanol volume fraction 50%,solid and liquid ratio 1∶50(g∶mL),and microwave power 500 W.The optimum extraction conditions of green tea in southern Guangxi were ethanol volume fraction 50%,solid and liquid ratio 1∶50(g∶mL),and microwave power 600 W.Under the optimized conditions,the yields of total flavonoids were(12.29±0.56)%,(12.51±0.39)%and(14.32±0.42)%,respectively.The results of in vitro antioxidant tests showed that the total flavonoids in 3 kinds of green tea had stronger DPPH radicals scavenging ability and certain hydroxyl radicals scavenging ability.