Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
Institute of Fruit and Tea, Hubei Academy of Agricultural Science, Wuhan 430064, China.
Food Chem. 2019 Jan 30;272:313-322. doi: 10.1016/j.foodchem.2018.08.013. Epub 2018 Aug 4.
Withering is an indispensable process for improving flavors in green, black and white teas during their manufacturing. The effects of the withering process on the formation of tea flavors were investigated using transcriptome and metabolite profiling in withered tea leaves. A total of 3268, 23,282 and 25,185 differentially expressed genes (DEGs) were identified at 3 h (68%, water content), 12 h (61%) and 24 h (48%) of the withering process, respectively. The DEGs, involved in flavonoid biosynthesis were significantly downregulated, which could be correlated with the reduction of catechins. Enhancement of terpenoids and alpha-linolenic acid metabolism could trigger an increase in the total content and number of volatiles. The increase in free amino acid-content could be related to 261 DEGs. Our study suggests that dehydration stress during withering induced significant changes in the gene transcription and content of the tea flavor compounds, which promoted the special flavors in various teas.
萎凋是绿茶、黑茶和白茶在制作过程中改善风味不可或缺的一道工序。本研究采用转录组和代谢组学方法研究了萎凋过程对茶叶风味形成的影响。在萎凋过程的 3 h（含水量 68%）、12 h（含水量 61%）和 24 h（含水量 48%），分别鉴定到 3268、23282 和 25185 个差异表达基因（DEGs）。参与类黄酮生物合成的 DEGs 显著下调，这与儿茶素的减少有关。萜烯和α-亚麻酸代谢的增强可能引发挥发性物质总量和数量的增加。游离氨基酸含量的增加可能与 261 个 DEGs 有关。本研究表明，萎凋过程中的脱水胁迫诱导了茶叶风味化合物基因转录和含量的显著变化，从而促进了各种茶叶具有独特的风味。
