## 3 Results and Discussion
### Multivariate Statistical Analysis
#### 3.4.3 Analysis of Key Differential Volatile Components
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Volatile Components**} & \multirow{2}{*}{**Thresholds (\(\mu\)g/kg)**} & \multicolumn{3}{c}{**rOAV**} \\ \cline{3-5}  & & **SPBT** & **SUBT** & **AUST** \\ \hline
3,4,5-Trimethyloxazole & - & - & - & - \\ Jasmin lactone & 2000 & \(<\)0.1 & - & \(<\)0.1 \\
5-Methyl-2-hexanol & 330 & \(<\)0.1 & - & \(<\)0.1 \\
2,6,11-Trimethyldodecane & - & - & - & - \\
2,6-Dimethyl-3,7-octadien-2,6-diol & - & - & - & - \\
2-Hexenal & 30 & - & 0.12 \(\pm\) 0.03 & - \\ Benzyl nitrile & 1000 & \(<\)0.1 & - & \(<\)0.1 \\
2,6,10-Trimethyldodecane & - & - & - & - \\ (Z)-3-Hexenate & - & - & - & - \\
2,6-Di-tert-butyl-4-methylphenol & 1000 & \(<\)0.1 & \(<\)0.1 & - \\ \(\beta\)-Ionone & 0.007 & \(263.75\pm 70.63\) & \(639.95\pm 22.18\) & \(215.70\pm 16.87\) \\ _Trans_-neralidol & 0.25 & \(8.18\pm 1.40\) & \(15.23\pm 2.06\) & \(18.83\pm 1.01\) \\ (E)-Citral & 0.5 & \(5.41\pm 1.34\) & - & - \\ Heptadecane & 10,000,000 & \(<\)0.1 & \(<\)0.1 & - \\ \hline \hline \end{tabular} Note: The threshold refers to that of the compound in water; the threshold values are sourced from the VCF website ([[https://www.vcf-online.nl/VcHome.cfm](https://www.vcf-online.nl/VcHome.cfm)]([https://www.vcf-online.nl/VcHome.cfm](https://www.vcf-online.nl/VcHome.cfm)) (accessed on 15 January 2025)) and the relevant literature [39; 40; 50; 52; 61; 62; 63; 64; 65].  
\end{table} 
Table 3: _Cont._difference is that in this study, summer black tea contains more linalool. Some studies have shown that lycopene can be oxidatively degraded into components such as linalool [60]. Lycopene belongs to carotenoids, which play a role as accessory pigments in the photosynthesis of tea plants and can be oxidatively degraded under factors such as light and high temperature [54]. It is speculated that the strong sunlight in summer promotes the oxidative degradation of lycopene, thus producing more linalool. This may be a reasonable explanation for this phenomenon. It is worth noting that [PERSON] et al. research shows that the sharp increase in the content of linalool in autumn black tea is related to the increase in glycosidic aroma precursors with the growth of tea leaves [13], which is contrary to the results of this study. This may be related to differences in tea varieties, processing techniques, and detection methods. \(\beta\)-ionone can also be formed by the degradation of carotenoids. Its high relative content in summer black tea may also be related to the abovementioned reasons. The strong light and high temperature in summer promote the oxidative degradation of carotenoids into \(\beta\)-ionone. Figure 6: Comparison of key differential volatile components in Rucheng Baimao black tea across different seasons. (**A**) Comparison of the relative contents of geraniol in black tea in different seasons; (**B**) comparison of the relative contents of methyl salicylate in black tea in different seasons; (**C**) comparison of the relative contents of nonanal in black tea in different seasons; (**D**) comparison of the relative contents of (\(E\))-citral in black tea in different seasons; (**E**) comparison of the relative contents of linalool in black tea in different seasons; (**F**) comparison of the relative contents of phenylacetaldehyde in black tea in different seasons; (**G**) comparison of the relative contents of benzaldehyde in black tea in different seasons; (**H**) comparison of the relative contents of phenethyl alcohol in black tea in different seasons; (**I**) comparison of the relative contents of benzyl alcohol in black tea in different seasons; (**J**) comparison of the relative contents of \(\beta\)-ionone in black tea in different seasons; (**K**) comparison of the relative contents of _trans_-neroidloid in black tea in different seasons. Different lowercase letters represent significant differences (\(p<0.05\)). The relative content of _trans_-nerolidol in summer and autumn black tea was significantly higher than that in spring (Figure 6K). It has a floral aroma characteristic.