非靶向代谢组学结合特征分子网络对不同等级抹茶非挥发性化合物的研究

目的 探究不同等级抹茶的非挥发性物质成分，分析影响样品代谢轮廓差异的非挥发性化合物。方法 使用高效液相色谱-质谱仪对抹茶样品中的非挥发代谢物进行检测，结合全范围天然产物社群分子网络对不同等级抹茶的差异化合物定性。结果 本研究在抹茶样品中共检测到784个化合物，其中553个化合物具有二级质谱图。样品等级影响抹茶的化学轮廓，样品依据轮廓相似性可分为两组。影响化学轮廓且有显著变化的差异代谢物共筛选出30个，其中29个化合物在样品3中含量更高，通过标准品和质谱图等方式定性了19个化合物，表儿茶素没食子酸酯、天冬氨酸、茶氨酸、精氨酸等。同时对4个等级抹茶中的儿茶素类进行探究，发现没食子儿茶素、没食子儿茶素没食子酸酯和表没食子儿茶素没食子酸酯的含量随等级的下降而减少。结论 本研究发现并定性了不同等级抹茶之间的差异化合物，为抹茶等级判定及标准化生产提供理论基础。

Nontargeted metabolomics combined with feature-based molecular networking to analyze the non-volatile components of different grades matcha

Objective To explore the non-volatile components of different grades of matcha, and analyze the non-volatile compounds that affect the differences of metabolic profile of samples. Methods The non-volatile metabolites in matcha samples were detected by high performance liquid chromatography-mass spectrometry, and the different compounds of different grades of matcha were identified by combining the whole range of natural product community molecular network. Results A total of 784 compounds were detected in matcha samples, of which 553 compounds had the tandem mass spectrometry. The grade of samples affected the chemical profiles of matcha, and the samples could be divided into two groups according to the profiles similarity. A total of 30 differential metabolites that affected the chemical profile and had significant changes were screened out, of which 29 compounds were higher in sample 3. Nineteen compounds, including epicatechin gallate, aspartic acid, theanine, and arginine, were identified by means of reference substances and mass spectrometry. Besides, the catechins in the four grades matcha were explored, and it was found that the contents of epigallocatechin gallate, epigallocatechin gallate and epigallocatechin gallate decreased with the decrease of grade. Conclusion This study found and characterized the difference compounds among various grades of matcha, and provide a theoretical basis for the grade judgment and normalization production of matcha.