## 3 Results and Discussion
### Analysis of Volatile Components in Black Tea from Different Seasons  
The volatile components of Rucheng Baimao black tea in different seasons were detected by HS-SPME-GC-MS. The results are presented in Table S1. A total of 140 volatile components were identified. Among them, 83 were detected in spring black tea, 88 in summer black tea, and 75 in autumn black tea. By comparing the relative contents of volatile components in black tea from spring, summer, and autumn, it was found that the relative content of produced black tea was the highest (286.45 \(\upmu\)g/kg), followed by that of spring black tea (259.68 \(\upmu\)g/kg), and the relative content of autumn black tea was the lowest (177.60 \(\upmu\)g/kg). The relative content of black tea was significantly lower than that of spring and summer black tea (Figure 1A). The 140 volatile components can be classified into seven categories according to functional groups: alcohols (27 types), aldehydes (14 types), esters (28 types), ketones (6 types), alkanes (41 types), alkenes (13 types), and others (11 types). By comparing the proportion of different categories of volatile components in Rucheng Baimao black tea in different seasons (Figure 1B-D), it was found that alcohols, esters, and alkanes had the highest proportion in each respective season. Alkanes have no distinct odor, and alcohols and esters may be the main contributors to the aroma quality of Rucheng Baimao black tea in different seasons. The formation of alcohols is mainly related to the hydrolysis of glycosidic aroma precursor substances and the biosynthetic pathways of volatile terpenoids. Most of these substances have floral and fruity scents and have a significant impact on the aroma quality of tea [53; 54]. Esters can be produced through the degradation of amino acids and fatty acids and play a crucial role in the formation of tea aroma. In particular, esters with C6-C9 carbon chains can exhibit pleasant floral, fruity, and fresh scents [10]. [PERSON] et al. proposed that alcohols, aldehydes, and esters are the main substances contributing to the formation of the aroma of 'Baimaocha black tea', which is consistent with the results of this study [7]. In addition, this study also statistically analyzed the top 10 volatile components in terms of relative content in black tea from different seasons (Figure 2). Geraniol had the highest relative content in spring black tea (66.34 \(\upmu\)g/kg), which was significantly higher than that in summer (10.25 \(\upmu\)g/kg) and autumn (9.99 \(\upmu\)g/kg). The volatile component with the highest relative content in both summer and autumn black tea was linaolo \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Tea Samples** & **Seasons** & **Aroma** & **Score** \\ \hline Spring & Floral–fruity aroma, refreshing sensation, with sweet fragrance & 90.20 \(\pm\) 1.17 a \\ Summer & Possesses a floral aroma & 82.40 \(\pm\) 0.80 c \\ Autumn & The floral fragrance is pure and harmonious & 86.60 \(\pm\) 1.36 b \\ \hline \hline \end{tabular} Note: Different lowercase letters indicate significant differences (\(p<\) 0.05).  
\end{table} 
Table 1: Sensory aroma evaluation of Rucheng Baimao black tea in different seasons. values of 51.83 \(\upmu\)g/kg and 32.22 \(\upmu\)g/kg, respectively. Methyl salicate ranked second among the volatile components in spring, summer, and autumn black tea. It has a fresh ascent similar to wintergreen and mint and may be a major contributor to the fresh aroma quality of Rucheng Baimao black tea [54]. Previously published research indicates that a high content of methyl salicate is associated with a high degree of freshness in Rucheng Baimao black tea, which is consistent with the results of this study [7]. It was also found that geraniol, linalool, methyl salicate, and phenethyl alcohol were common among the top 10 volatile components in black tea from different seasons, suggesting that these volatile components play important roles in the aroma quality of Rucheng Baimao black tea in all three seasons.