反式儿茶素类与表儿茶素类浸提规律的比较研究

利用HPLC分析技术,测定茶叶儿茶素中8种单体在沸水浸提过程中的浓度-时间变化,结合浸提动力学基本模型,对表儿茶素类与反式儿茶素类单体的沸水浸提动态进行系统研究,分析EGCG/总儿茶素、GCG/总儿茶素的动态变化。结果表明,表儿茶素类的浸提速率显著快于反式儿茶素类,浸提率于5min时达到最大值,之后随着时间延长而下降;反式儿茶素类的浸提率则一直处于明显增长状态,浸提结束时达到最高值。根据浸提速率常数K_obs,8种单体的浸出快慢顺序为：EC>EGC>EGCG>ECG> GC>C>GCG >CG。

Comparative Research on the Extraction Regularity of Trans-Catechins and Epicatechins

Using the HPLC technique,changes of concentration of eight catechin monomers versus time in boiling infusion were measured.Extraction kinetics of epicatechins and trans-catechins were systematically studied by applying a two-phase model in determining the kinetic and equilibrium data.Dynamic changes of ratios of EGCG and GCG to total catechin were studied,too.The results showed that epicatechins infused faster than trans-catechins dramaticlly,the former reached its maximum at 5 min,then the value declined w...