基于电子舌和代谢组学分析揉捻转速对工夫红茶品质的影响

为探索揉捻转速(35、45、55、60r/min)对工夫红茶风味品质及内质成分的影响，采用鸠坑群体种开展不同揉捻转速的制茶实验。通过感官分析与电子舌分析、色差分析相结合，探究不同揉捻转速对工夫红茶滋味、汤色等风味品质的影响；采用系统分析法和高效液相色谱法对茶色素和总茶黄素组分开展定量分析；利用基于超高效液相色谱-四极杆-静电场轨道阱高分辨质谱的代谢组学技术对4种揉捻转速所制得工夫红茶中非挥发性成分进行检测；并结合偏最小二乘判别分析及单因素方差分析，探究不同揉捻转速对工夫红茶内质成分的影响。结果显示，45r/min揉捻所制得的工夫红茶感官品质最佳，滋味和香气品质较优，电子舌和色差分析验证了45r/min揉捻制得的工夫红茶滋味和汤色品质较佳。不同揉捻转速制得的工夫红茶中有16种差异化合物，主要是原花青素C₁、牡荆素、异牡荆素、天冬酰胺、天冬氨酸、没食子酸、苹果酸、琥珀酸和葡萄糖酸等，揉捻转速对酚酸类、有机酸类、茶黄素、茶红素和茶褐素等影响相对较大，对其他成分影响相对较小。45r/min揉捻制得的工夫红茶中茶红素、品质指数、糖类、天冬氨酸等含量较高，而有机酸类、酚酸类和...

Analysis of the Effect of Rolling Speed on the Congou Black Tea Quality Using Electronic Tongue and Metabolomics

This research was undertaken to explore the effects of different rolling speeds (35, 45, 55 and 60 r/min) on the flavor quality and internal quality components of Congou black tea from the Jiukeng cultivar. Flavor attributes including taste and color were determined by sensory evaluation, color difference analysis and electronic tongue analysis. Quantitative analysis of tea pigments and theaflavin components were performed by systematic analysis and high-performance liquid chromatography (HPLC). In addition, metabolomics based on ultra-high performance liquid chromatography-quadrupole orbitrap high resolution-mass spectrometry (UPLC-Q-Orbitrap-MS) was used to determine the non-volatile compounds in Congou black tea. Partial least squares discriminant analysis (PLS-DA) and one-way analysis of variance (ANOVA) were used to investigate the effect of different rolling speeds on the internal quality components of Congou black tea. The results showed that a rolling speed of 45 r/min resulted in the best sensory quality of Congou black tea, especially in taste and aroma, as verified by color difference and electronic tongue analysis. Sixteen significantly differential metabolites were identified among the four tea samples, including procyanidin C1, vitexin, isovitexin, asparagine, aspartic acid, gallic acid, malic acid, succinic acid, and gluconic acid. It was found that rolling speed showed a significant influence on phenolic acids, organic acids and tea pigments (theaflavins, thearubigins, and theabrownins), but had little effect on other metabolites. The contents of thearubigins, carbohydrates and aspartic acid and quality index were highest in Congou black prepared with a rolling speed of 45 r/min, and the contents of organic acids, phenolic acids and theabrownins were lowest, which indicated that this rolling speed was more favorable for the formation of the flavor quality of Congou black tea. This study is expected to provide a theoretical basis and technical guidance for the improvement of Congou black tea quality and the precise production of Congou black tea.