An Tingting, Chen Mengxue, Zu Zhongqi, Chen Qi, Lu Hengqian, Yue Pengxiang, Gao Xueling
State Key Laboratory of Tea Plant Biology and Utilization, Key Laboratory of Food Nutrition and Safety, Anhui Engineering Laboratory for Agro-products Processing, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei 230036, Anhui, China.
School of Life Sciences, Anhui University, Hefei 230601, Anhui, China.
Food Res Int. 2021 Oct;148:110623. doi: 10.1016/j.foodres.2021.110623. Epub 2021 Jul 21.
Instant green tea powder was used as raw material to prepare an instant dark tea via liquid-state fermentation by Eurotium cristatum. To understand how the chemical constituents present in fermented green tea develop during fermentation, samples were collected on different days during fermentation for qualitative analyses by ultra-performance liquid chromatography-Q Exactive Orbitrap/Mass spectrometry. Untargeted metabolomics analyses revealed that the levels of original secondary metabolites in the instant green tea changed significantly from day 3 to day 5 during fermentation. Targeted metabolomics indicated that the levels of galloylated catechins (GCs) and free amino acids (FAAs) significantly decreased, but the nongalloylated catechins (NGCs), alkaloids, thearubigins and theabrownins increased dramatically after fermentation. The changes in the contents of catechins, gallic acid and free amino acids in the instant dark tea samples were positively related to the DPPH radical scavenging activities in vitro, and the phenolic acids and FAAs were positively related to the inhibitory effects towards α-glucosidase. These results showed that fermentation by Eurotium cristatum is critical to the formation of certain qualities of instant dark tea.
以速溶绿茶粉为原料，通过冠突散囊菌液态发酵制备速溶黑茶。为了解发酵绿茶中化学成分在发酵过程中的变化情况，在发酵的不同天数采集样品，采用超高效液相色谱 - Q Exactive Orbitrap/质谱进行定性分析。非靶向代谢组学分析表明，速溶绿茶中原有的次生代谢产物水平在发酵第3天到第5天期间发生了显著变化。靶向代谢组学表明，发酵后，没食子酰化儿茶素（GCs）和游离氨基酸（FAAs）水平显著降低，但非没食子酰化儿茶素（NGCs）、生物碱、茶红素和茶褐素大幅增加。速溶黑茶样品中儿茶素、没食子酸和游离氨基酸含量的变化与体外DPPH自由基清除活性呈正相关，酚酸和FAAs与对α - 葡萄糖苷酶的抑制作用呈正相关。这些结果表明，冠突散囊菌发酵对速溶黑茶某些品质的形成至关重要。
