State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China; International Joint Laboratory on Tea Chemistry and Health Effects of Ministry of Education, Anhui Agricultural University, Hefei 230036, China.
State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei 230036, China; International Joint Laboratory on Tea Chemistry and Health Effects of Ministry of Education, Anhui Agricultural University, Hefei 230036, China.
Food Chem. 2025 Jan 15;463(Pt 2):141222. doi: 10.1016/j.foodchem.2024.141222. Epub 2024 Sep 12.
While key aroma and taste compounds of Keemun Congou black teas (KCBT) form during aeration and thermal stages, it is still unknown whether these processing stages also produce non-volatile color-contributing metabolites. Through integrating metabolomics with correlation and ridge regression analyses, 190 metabolites were identified as marker compounds that reclassified 15 KCBT samples collected from five processing stages into four groups. Meanwhile, the results of quantification and heatmap analysis showed that the concentrations of theaflavins and theasinensins significantly increased, as catechin decreased, after rolling, while flavonoid aglycones and polyunsaturated fatty acids increased throughout drying. Regression analysis between marker compound levels and total color difference values (∆E) revealed that the major color contributors were 3,5-dicaffeoylquinic acid, glucosyl-dehydrodigallic acid, theacitrin A, kaempferol-O-robinobioside, and (-)-epigallocatechin, with regression coefficients (absolute value) exceeding 4 × 10. Overall, the present study confirmed that rolling and drying were the two vital stages responsible for the color formation of KCBT.
虽然祁门工夫红茶（KCBT）的关键香气和滋味化合物是在充气和热阶段形成的，但这些加工阶段是否也会产生非挥发性的颜色贡献代谢物仍不清楚。通过将代谢组学与相关和岭回归分析相结合，鉴定出 190 种代谢物作为标记化合物，将来自五个加工阶段的 15 个 KCBT 样品分为四组。同时，定量和热图分析的结果表明，揉捻后茶黄素和茶红素的浓度显著增加，儿茶素含量降低，而在整个干燥过程中，类黄酮糖苷和多不饱和脂肪酸的浓度增加。标记化合物水平与总色差值（∆E）之间的回归分析表明，主要的颜色贡献者是 3,5-二咖啡酰奎宁酸、葡萄糖基-脱氢二没食子酸、茶黄素 A、山奈酚-O-槐糖苷和（-）-表儿茶素，其回归系数（绝对值）超过 4×10。总的来说，本研究证实了揉捻和干燥是 KCBT 形成颜色的两个重要阶段。
