不同pH条件下TSs的形成机理及其与TFs的竞争性形成研究  

Formation Mechanism of TSs and Competitive Formation Between TSs and TFs under Various pH

作　　者：徐斌[1,2] 江和源[1] 张建勇[1] 杨刘艳 刘千录 

机构地区：[1]中国农业科学院茶叶研究所农业部茶树生物学与资源利用重点实验室浙江省茶叶加工工程重点实验室,浙江杭州310008 [2]中国农业科学院研究生院,北京100081

出　　处：《茶叶科学》2015年第3期281-289,共9页Journal of Tea Science

基　　金：国家茶叶产业技术体系(CARS-23);农业技术试验示范项目(A8289);浙江省三农六方科技协作计划项目(2011006)

摘　　要：采用液态发酵的方式,结合不同的p H条件,通过酶促氧化儿茶素生成相应聚酯型儿茶素(Theasinensins,TSs)或茶黄素(Theaflavins,TFs)的单体物质来深入探讨TSs的形成机理及其与TFs的竞争性形成。结果表明,酸性条件下,TSs的单体物质能够持续生成,而且一直积累;中性和碱性条件下生成的TSs单体物质达到最大值的时间很短,稳定性较差。不同p H条件下,由于自身氧化还原电位值的高低,各个儿茶素单体之间被氧化而消耗的速率有所差别,而且基于生成TSs和TFs需要共同的儿茶素底物,因此两者的形成具有竞争性。p H=6和中性条件下EGCG和EGC转化形成TSs单体的量高于形成TFs的量,而p H=5水平下则相反。To illustrate the formation mechanism of thea sinensins（TSs） and the competitive formation between TSs and theaflavins（TFs）, catechins（（EGCG, EGC, EC and ECG） were oxidized to form TSs monomers or TFs monomers by enzymatic oxidation and the experiments were performed by liquid fermentation under dif ferent p H values. The results showed that the TSs monomers were synthesized and accumulated continuously under acidic conditions, while the peaks of TSs monomers appeared in a short time but showed poor stability under neutral or alkaline conditions. Due to the magnitudes of the oxidation reduction potential（ORP） are variable for catechin s, the enzymatic oxidative rates of catechin s are different under different p H conditions. For the reason that there was a competition between the formation of TSs and TFs ： the content of TSs monomers transformed by EGCG and EGC was higher than TFs monomers under the neutral condition or p H=6, however, conversely under the condition p H=5.

关 键 词：儿茶素 聚酯型儿茶素 茶黄素 形成机理 竞争性 

分 类 号：Q946[生物学—植物学]