基于亲水相互作用液相色谱-三重四极杆质谱法研究白茶萎凋过程中代谢物的变化

采用亲水相互作用液相色谱-三重四极杆质谱法,对白茶鲜叶(F)和室内萎凋处理29 h(W)、53 h(P)的2个萎凋样进行了代谢物靶向检测,Quality control(QC)样本中共检测到111个代谢物,主要包括47种氨基酸及其衍生物、29种核酸类代谢物、12种维生素和辅酶、17种糖代谢物和6种甘油磷脂代谢物。与鲜叶F相比,萎凋叶W和P中显著增加的代谢物分别有39种和41种,其中共有代谢物35种;显著降低的代谢物分别有9种和11种,其中共有代谢物8种。显著变化代谢物分析结果表明,萎凋叶的细胞膜受损、DNA和RNA降解、氨基酸衍生物显著增加、糖代谢异常。根据代谢物含量的变化幅度和组成特异性,筛选了表征萎凋叶细胞膜生理状态和核酸、糖代谢的标志代谢物。此外,针对代谢物中氨基酸和核苷酸的组成特点,提出了研究氨基酸衍生物滋味特性的必要性和应用代谢谱分析建立萎凋工艺适度标准的可能性。

The Changes of Metabolites during the Withering Process of White Tea Based on HILIC LC-QqQ MS Method

In this study, the metabolic profiles of fresh leaves (F), two indoor withered samples for 29 h (W) and 53 h (P) respectively were investigated by HILIC-QqQ MS based targeted metabolomics. Totally 111 metabolites were detected in the QC sample, including 47 amino acids and their derivatives, 29 nucleic acid metabolites, 12 vitamins and coenzymes, 17 sugar metabolites and 6 glycerophospholipid metabolites. Compared with the fresh leaves (F), 39 and 41 metabolites were significantly increased in withered samples W and P, with 35 overlapped metabolites. On the other hand, 9 and 11 metabolites were dramatically reduced, with 8 overlapped metabolites. The metabolite changes suggested that the cell membranes were damaged, DNA and RNA were degraded, amino acids derivatives were significantly increased and glucose metabolism was abnormal. Furthermore, according to the variations of metabolite contents and compositions, the marker metabolites of the withered leaves were identified which could reflect the physiological states of cell membrane, nucleic acid and glucose metabolism. Eventually, based on the characteristic changes in amino acids and nucleotides, the necessities of characterizing the flavor properties of amino acids and their derivatives as well as exploring the possibility of using metabolic profiling as white tea withering standards were proposed.