## 3 Results and Discussion
### Volatile Compound Analysis of Black Tea Under Different Shaking Combinations  
#### 3.2.1 Qualitative and Quantitative Analysis of Volatile Compounds  
A total of 53 volatile components were identified across different black tea samples (Table S1), including fourteen alcohols, twelve olefins, eleven esters, nine aldehydes, two ketones, one ether, one organosulfur compound, one aromatic compound, one heterocyclic compound, and one acid. The addition of shaking or shaking combinations during withering increased the number of volatile substances in black tea, with the YLS treatment group showing the highest number of volatile compounds (Figure 2A). Venn diagram analysis revealed 30 common volatile compounds across all samples, with six overlapping volatiles in four shaking-involved treatments, including benzyl alcohol, cis-3-hexenyl isovalerate, cedryl acetate, \(\beta\)-copaene, D-limonene, and 2-pentyl-furan (Figure 2B). Five components, such as \(\beta\)-guaiene, \(\alpha\)-alaskene, 10-undecenyl-3-phenylpropanoate, 2-ethyl-1-hexanol, and geranyl vinyl ether, were unique to YLS, while geranyl isovalerate and trans-2-hexenoic acid were unique to HTS. No unique substances were detected in S and HYS. These findings suggest that shaking increases the variety of volatile compounds, and additional withering \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample** & **Appearance** & **Infusion Color** & **Aroma** & **Taste** & **Infused Leaf** & **Total Score** \\ \hline CK & 90.00 \(\pm\) 0.00 a & 90.23 \(\pm\) 0.21 a & 85.00 \(\pm\) 0.41 d & 88.23 \(\pm\) 0.21 c & 90.00 \(\pm\) 0.00 a & 88.24 \(\pm\) 0.13 d \\ S & 90.00 \(\pm\) 0.00 a & 90.32 \(\pm\) 0.13 a & 88.23 \(\pm\) 0.21 b & 90.17 \(\pm\) 0.12 b & 90.00 \(\pm\) 0.00 a & 89.64 \(\pm\) 0.06 b \\ YLS & 90.00 \(\pm\) 0.00 a & 90.67 \(\pm\) 0.24 a & 90.57 \(\pm\) 0.33 a & 92.23 \(\pm\) 0.21 a & 90.00 \(\pm\) 0.00 a & 90.88 \(\pm\) 0.09 a \\ HTS & 90.00 \(\pm\) 0.00 a & 88.50 \(\pm\) 0.41 b & 87.33 \(\pm\) 0.24 c & 90.07 \(\pm\) 0.09 b & 90.00 \(\pm\) 0.00 a & 89.20 \(\pm\) 0.11 c \\ HYS & 90.00 \(\pm\) 0.00 a & 84.23 \(\pm\) 0.21 c & 88.07 \(\pm\) 0.09 b & 87.13 \(\pm\) 0.09 d & 90.00 \(\pm\) 0.00 a & 88.08 \(\pm\) 0.07 d \\ \hline \hline \end{tabular}  
* The numerical values presented in this table represent the evaluation scores (mean \(\pm\) SD, n = 5 panelists),, which are graded on a 100-point scale. The total scores were computed with the following weightings: appearance constitutes 20%, infusion color accounts for 10%, aroma makes up 30%, taste represents 30%, and infused leaves contribute 10% [21]. Treatments: CK represents indoor natural withering, S represents shaking, YLS represents yellow light plus shaking, HTS represents high temperature plus shaking, HTS represents high temperature plus shaking, HTS represents high temperature with yellow light plus shaking. Different letters in the same column indicate a significant difference between different withering treatments (\(p<0.05\)).  
\end{table} 
Table 1: Sensory evaluation of black tea under different shaking combinations. ing treatments (YLS and HTS) can further enhance this effect, thus changing the volatile composition of black tea. Quantitative analysis showed that different shaking combinations improved the content of various volatile categories (Figure 2C). YLS had the highest content of alcohols, aldehydes, olefins, esters, and other compounds, leading to the highest level in total volatile content (Figure 2D). Compared to CK, S and HTS also promoted the accumulation of these categories, while HTS only significantly increased alcohol content. Major alcohols such aslinal, cedrol, and trans-linaloid oxide (furanoid) increased significantly after shaking combinations, contributing to the overall increase in alcohol content. Similarly, S, YLS, and HTS increased the content of main aldehydes (e.g., 3-methylbutyrate), olefins (e.g., \(\beta\)-cedrene and \(\alpha\)-cedrene), esters (e.g., \(\alpha\)-terpinyl acetate), and other compounds (e.g., dimethyl sulfide).