黑茶中茶多酚的醇水超临界CO2流体联合提取
Solvent- SCF co- extraction of tea polyphenols from black tea
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摘要: 以自制黑茶为研究对象,分别采用超临界CO2萃取法、醇水浸提法及醇水浸提-超临界CO2联合萃取法对茶样中的茶多酚进行提取,用正交实验法优化了提取条件,以没食子酸为标准品,在765nm处用紫外可见分光光度法检测产品中茶多酚的含量,计算了茶多酚的得率及萃取样中产品的纯度,并对三种产品的DPPH·清除率进行了比较。结果表明:3种方法中醇水-超临界CO2联合萃取法的得率和纯度最高。联合浸提最优条件为:先用乙醇浓度80%,料液比1∶10g/m L,60℃下浸提2.0h,然后25MPa,50℃下超临界CO2萃取时间2h。茶多酚的得率为6.36%±0.81%,产品纯度为:41.22%±3.19%。产品对DPPH·的清除率为90.64%±0.0187%。该方法绿色环保,未添加任何有害溶剂,为黑茶饮品的进一步研究开发提供参考。Abstract: Homemade black tea as research object,Supercritical CO2 fluid extraction( SCF),Solvent leaching and SCF- Solvent co- extraction were used to extract tea polyphenols from black tea with orthogonal tests to optimize the extraction technology,then the yields and purities of tea polyphenols in the samples which were calculated after ultraviolet detection at 765 nm with gallic acid as standard sample. And the DPPH· clearance rates were studied between the extraction methods.The results showed that the Solvent- SCF co- extraction was the best method.After Solvent leaching( ethanol concentration 80%,solid to liquid 1 ∶ 10 g / m L,extraction temperature 60℃,extraction time 2h),the solution were extracted with SCF at 25 MPa,50℃ for 2h.Under the best conditions for the Solvent- SCF co- extraction method,high yield and high purity of tea polyphenols can be obtained with yield of6.36% ± 0.81% and purity of 41.22% ± 3.19%.The DPPH·clearance rate of products was 90.64% ± 0.0187%.This method was environmental protection,not adding any harmful solvents,which can provide the reference for the further development of black tea research.