Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Sciences, 9 Meiling South Road, Hangzhou, Zhejiang 310008, People's Republic of China.
Zhejiang Provincial Center for Disease Control and Prevention, 3399 Binsheng Road, Hangzhou, Zhejiang 310051, People's Republic of China.
Food Res Int. 2018 Apr;106:909-919. doi: 10.1016/j.foodres.2018.01.069. Epub 2018 Jan 31.
Three subtypes of white tea, Silver Needle (SN), White Peony (WP), and Shou Mei (SM), differ in their taste, aroma, bioactivity, and commercial value. Here, a metabolomics investigation on the chemical compositions combining taste equivalent-quantification and dose-over-threshold (DoT) determination on the taste qualities were applied to comprehensively characterize the white tea subtypes for the first time. Significant differences in the contents of catechins, dimeric catechins, amino acids, phenolic acids, flavonol/flavone glycosides, and aroma precursors were observed among these 3 white teas. Metabolite content comparison and partial least-squares (PLS) analysis suggest that theanine, aspartic acid, asparagine, and AMP were positively correlated with the umami taste in white tea, and flavan-3-ols, theasinensins, procyanidin B3, and theobromine had positive correlations with higher bitterness and astringency tastes. In addition, puckering astringent (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG) and theogallin, bitter-tasting caffeine, and the mouth-drying/velvety-like astringent γ-aminobutyric acid (GABA) were identified as key taste compounds of white tea infusion by absolute quantification and DoT factor calculations. This work provided systematic and comprehensive knowledge on the chemical components, taste qualities, and sensory active metabolites for the subtypes of white tea.
白茶的三个品种，银针（SN）、白牡丹（WP）和寿眉（SM），在口感、香气、生物活性和商业价值方面存在差异。在这里，我们首次应用代谢组学研究方法，结合味觉等效定量和阈上因子（DoT）测定对味觉品质的化学组成进行综合分析，全面表征了这三种白茶的特征。结果表明，这三种白茶之间的儿茶素、二聚儿茶素、氨基酸、酚酸、黄酮醇/黄酮苷和香气前体的含量存在显著差异。代谢物含量比较和偏最小二乘（PLS）分析表明，天冬氨酸、天冬酰胺、茶氨酸和 AMP 与白茶的鲜味呈正相关，而黄烷-3-醇、茶黄素、原花青素 B3 和可可碱与更高的苦味和涩味呈正相关。此外，收敛性涩味（-）-表没食子儿茶素没食子酸酯（EGCG）、（-）-表儿茶素没食子酸酯（ECG）和茶鞣酸、苦昧咖啡因以及口干/天鹅绒般涩味γ-氨基丁酸（GABA）被鉴定为白茶浸提液的关键味觉化合物，通过绝对定量和 DoT 因子计算得出。这项工作为白茶的化学组成、口感品质和感官活性代谢物提供了系统而全面的知识。
