低共熔溶剂提取绿茶总黄酮及其抗氧化活性

Research on extraction of total flavonoids from green tea with deep eutectic

目的:优化低共熔溶剂提取绿茶总黄酮工艺,并评价其抗氧化活性。方法:以总黄酮提取率为考察指标,以低共熔溶剂种类、液料比、提取温度和提取时间为影响因素,采用正交试验优化低共熔溶剂提取绿茶总黄酮工艺参数,并对其抗氧化活性进行评价。结果:绿茶总黄酮的最优提取工艺为以80%乙酰胆碱—乳酸(n_(乙酰胆碱)∶n_(乳酸)=1∶1)水溶液为低共熔溶剂,液料比(V_(溶剂)∶m_(绿茶))30∶1(mL/g),提取温度90℃,提取时间75 min,此条件下绿茶总黄酮提取率为1.84%,总黄酮质量浓度为65.8 mg/mL。一定质量浓度范围内,绿茶总黄酮提取液对DPPH自由基和OH自由基的清除能力强于维生素C。结论:以80%乙酰胆碱—乳酸(n_(乙酰胆碱)∶n_(乳酸)=1∶1)水溶液为低共熔溶剂提取的绿茶总黄酮具有一定的抗氧化活性。

Objective:This study aimed to optimize the extraction technology of total flavonoids from green tea with Deep Eutectic Solvents(DESs)and evaluate the antioxidant activity of total flavonoids extracted from green tea under optimal conditions.Methods:The extraction rate of total flavonoids was taken as the index,with the ratio of liquid to solid,extraction temperature and extraction time taken as the influencing factors,and the extraction process parameters were optimized by orthogonal test,followed by the antioxidant activity evaluating with DPPH free radical inhibition.Results:The optimal extraction conditions for extraction of total flavonoids from green tea with DESs were 80% acetylcholine-lactic acid solution(acetylcholine∶lactic acid=1∶1),with ratio of liquid to solid 30∶1(mL/g),extraction at 90℃ for 75 min.Under the control of these conditions,the extraction yield of total flavonoids was 1.84%,and the concentra-tion of total flavonoids was 65.8 mg/mL.The research on antioxidant activity showed that in a certain concentration range,the antioxidant activity of total flavonoids extract from green tea was stronger than that of vitamin C.Conclusion:Under the control of the optimal technological conditions,the total flavonoids extracted from green tea with 80%acetylcholine-lactic acid solution as eutectic solvent had certain antioxidant activity.