EGCG氧化聚合物关键呈色物的鉴定及其显色效应研究

夏秋茶资源含有丰富的儿茶素，但缺乏有效的利用途径。儿茶素氧化呈现不同的显色效应，其氧化显色物质是天然食用色素的潜在来源。然而，儿茶素氧化显色物质的结构特征及其显色效应还不清晰。本项目将以儿茶素EGCG的单体氧化为切入点，前期探索表明EGCG的单体溶液在不同温度及pH处理下会发生明显的规律显色反应，后续将构建EGCG单体溶液的梯度氧化显色模型；建立基于LC-MS的非靶向分析方法，结合高分辨质谱的精确质量及裂解规律等技术，挖掘并定性具有显色效应的EGCG呈色聚合物；最后将进一步分析EGCG呈色聚合物在不同条件及不同体系中的显色效应及影响因素。本项目的研究结果不仅可以指导开发天然食用色素，同时可以完善茶叶品质化学理论，为提高夏秋茶资源的利用率提供科学基础。

Summer and autumn tea resources are rich in catechins, but there are no effective ways to use catechins. The oxidation of catechins presents different coloring effects, and the oxidized coloring substances are the potential sources of natural food pigments. However, the structures and coloring effects of catechins oxidized coloring substances are not clear yet. This study will start with the oxidation of EGCG monomer. The preliminary exploration showed that obvious regular coloring reactions occurred in EGCG monomer solution under different temperature and pH treatments. Next, the coloring model of gradient oxidation of EGCG monomer solution will be constructed. Non-targeted analysis method based on LC-MS will be established to discover and identify EGCG oxidized polymers with coloring effects. Finally, the coloring effects and their influencing factors of EGCG oxidized coloring polymers under different conditions and different tea systems will be further analyzed. The research results of this study can not only guide the development of natural food pigments, but also improve the chemical theories of tea quality. Besides, this study will provide a scientific basis for improving the utilization of summer and autumn tea resources.