普洱茶后发酵过程中多酚类成分生物转化的研究进展

普洱茶产于云南，属于后发酵茶，是我国黑茶的典型代表之一。微生物参与的后发酵过程使晒青毛茶中的多酚类成分发生了一系列复杂的诸如氧化、聚合、缩合、分解等为主的电化学变化，奠定了普洱茶的化学物质基础，赋予了普洱茶特殊的风味品质和保健功效。近年来的研究表明，普洱茶后发酵过程中，在微生物分泌的胞外酶作用下，糖基化、甲基化以及其他类型取代方式的化学结构修饰也是多酚类成分生物转化的重要途径之一，以此形成了众多多酚类成分的化学结构修饰产物。现有研究表明，这些结构修饰产物对普洱茶的风味品质和生物活性产生重要影响，是普洱茶中潜在的重要品质化学成分和标志性成分，具有重要的研究意义。本文综述了普洱茶中多酚类成分化学结构修饰产物的研究进展。

Recent Advances in Research on Biotransformation of Polypheonls during Pu-erh Tea Pile Fermentation

Pu-erh tea is a unique fermented tea produced from the sun-dried leaves of large-leaf tea species (Camellia sinensis (Linn.) var. assamica (Masters) Kitamura) in Yunnan province of China. The special sensory characteristics and beneficial health effects of Pu-erh tea arise from the multitudinous chemical changes and transformations (oxidation, polymerization, condensation and decomposition) of polyphenolic constituents in sun-dried green tea leaves during the pile fermentation process. Recent studies have revealed that structural modification of polyphenols catalyzed by microbial extracellular enzymes during the pile fermentation of Pu-erh tea, such as methylation, glycosylation and other substitution patterns is an important pathway of polyphenol biotransformation in sun-dried green tea leaves, forming a wide variety of derivatives, which have been demonstrated in previous studies for their important influence on the flavor quality and bioactivity of Pu-erh tea. These compounds are marker ingredients and quality constituents in Pu-erh tea, and are of significant research interest. This paper reviews recent advances in research on chemical modification of polyphenols during the pile fermentation of Pu-erh tea.