茶叶中茶多酚和生物碱的测定及聚类和线性判别分析  

Determination of Polyphenols and Alkaloids in Tea and Cluster-Linear Discrimination Analysis

作　　者：肖俊松[1,2] 袁英髦[1] 张爱雪[1] 曹雁平[1,2] 

机构地区：[1]北京工商大学化学与环境工程学院,北京100048 [2]食品添加剂与配料北京高校工程研究中心,北京100048

出　　处：《食品科学》2010年第22期343-348,共6页Food Science

基　　金："十一五"国家科技支撑计划项目(2006BAD27B03);北京市自然科学基金项目(3062007)

摘　　要：目的:建立一种反相高效液相色谱方法,测定绿茶、乌龙茶、红茶、白茶和普洱茶中儿茶素[(+)-catechin,C]、表儿茶素[(-)-epicatechin,EC]、表儿茶素没食子酸脂[(-)-epicatechin gallate,ECG]、表没食子儿茶素[(-)-epigallocatechin,EGC]、表没食子儿茶素没食子酸脂[(-)-epigallocatechin gallate,EGCG]、没食子酸(gallic acid,GA)、咖啡因(caffeine,CAF)、可可碱(theobromine,THEO)的水平。以这8种组分为指标对茶叶进行聚类分析和线性判别分析,建立区分绿茶、红茶和乌龙茶的方法。方法:茶叶提取后采用HPLC法测定儿茶素和生物碱含量,色谱柱为C18柱,流动相由甲醇(A)、2%的乙酸(B)等度洗脱,A、B相的体积比为25:75,流速为1mL/min,柱温30℃。采用PDA检测器在278nm检测,参考波长为210nm。采用SPSS14.0对实验数据进行了聚类分析和线性判别分析。结果:在选择的分析条件下,样品中的8种组分获得了理想分离,加标回收率在87%～112.8%之间,并采用外标法对8种组分进行定量。以这8种组分的含量为指标,聚类分析和线性判别分析能对39种茶叶样品进较好的区分。Objective： To establish a HPLC method for the determination of （＋）-catechin, （-）-epicatechin （EC）, （-）-epicatechin gallate （ECG）, （-）-epigallocatechin （EGC）, （-）-epigallocatechin gallate （EGCG）, gallic acid （GA）, caffeine （CAF） and theobromine （THEO） in green, oolong and black tea samples, and to develop a discrimination method for green, oolong and black tea by cluster analysis and linear discrimination analysis on the basis of determined chemical components. Methods： Tea samples were extracted by 70% aqueous methanol. Totally 200 mg of grinded tea samples was extracted with 5 mL of 70% aqueous methanol for 10 min in 70 ℃water bath. The extract was centrifuged at 3500 r/min for 10 min, and the supernatant was collected. Then the precipitate was extracted with 5 mL of 70% methanol under the same conditions. The supernatants were combined in a volumetric flask and diluted to 10 mL. A total of 2 mL of such solution was diluted by 5 times with stabilizing solution, filtrated with 0.45 μm membrane, and then used for HPLC analysis. Eight compounds were separated by a C18 column using a mobile phase containing methanol-2% aqueous acetic acid at a ratio of 25：75 （V/V） in an isocratic elution at 30 ℃, and detected using a photodiode array detector at 278 nm with the reference wavelength at 210 nm. The cluster and linear discrimination analyses were performed using SPSS 14.0 software. Results： Eight compounds in all tea samples were well separated under the proposed conditions. The recovery rates of spiked samples were in the range of 87%-112.8%. The contents of 8 compounds determined by an external standard method were used to conduct cluster analysis and linear discrimination analysis. The good differentiation of green, oolong and black tea samples were achieved. Conclusion： This established method is feasible to discriminate green, oolong and black tea.

关 键 词：茶多酚 咖啡碱 茶叶 高效液相色谱 聚类分析 线性判别分析 

分 类 号：TS255.36[轻工技术与工程—农产品加工及贮藏工程]