## 4 Conclusions  
In this study, the sensory characteristics and volatile profiles of white teas harvested in spring and autumn were investigated. Through a sensory evaluation of 'Sanhua1951' and 'Fudingdabai', it was found that spring white teas (SH-S, FD-S) were superior to autumn teas (SH-A, FD-A) in appearance, aroma, and taste. Significant differences were observed in the levels of catechins, caffeine, tea polyphenols, and amino acids between the four groups. Specifically, the contents of EGC, soluble sugar, and amino acids were significantly higher in spring teas compared to autumn teas (\(p<0.05\)). Conversely, the levels of ECG, C,  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**No. **} & \multirow{2}{*}{**Index**} & \multirow{2}{*}{**Odor Description a**} & \multirow{2}{*}{**Threshold**} & \multicolumn{4}{c}{**OAV**} \\ \cline{5-8}  & & & \(\mu\)g/L & & **SH-S** & **SH-A** & **FD-S** & **FD-A** \\ \hline \multirow{2}{*}{10} & \multirow{2}{*}{Oct-1-en-3-ol} & grass, oily, earthy, fungal, vegetative-like, fresh, mushroom-like & 1 [62] & 0.881 a  & 0.909 a  & 1.199 a  & 1.158 a  \\ \hline \multirow{2}{*}{11} & (E)-Linalool oxide & fresh, citrus, fruity & 6 [53] & 0.976 d  & 2.028 b  & 2.014 c  & 4.294 a  \\ \hline \multirow{2}{*}{12} & \multirow{2}{*}{Linalool grape-like, woody} & floral, sweet, grape-like, woody & 0.22 [62] & 348.887 b  & 387.96 d  & 464.531 a  & 409.690 a  \\ \hline \multirow{2}{*}{13} & \multirow{2}{*}{Geraniol} & \multirow{2}{*}{rose-like, sweet, waxy} & 40 [62] & 2.491 a  & 1.302 b  & 2.702 a  & 1.395 b  \\ \hline \multirow{2}{*}{14} & (Z)-Jasmone & floral, Jasmin, woody, herbal & 1.9 [62] & 4.583 b  & 1.120 c  & 6.359 a  & 0.804 c  \\ \hline \multirow{2}{*}{15} & \multirow{2}{*}{\(\alpha\)-Ionone} & sweet, fruity, woody, floral & 0.4 [62] & 8.494 a  & 4.759 b  & 11.499 a  & 4.717 b  \\ \hline \multirow{2}{*}{16} & \multirow{2}{*}{\(\beta\)-ionone} & sweet, fruity, woody, floral & 0.007 [62] & 2406.334 a  & 1439.131 b  & 3375.147 a  & 1475.371 b  \\ \hline \multirow{2}{*}{17} & \multirow{2}{*}{\(\beta\)-Pinene} & pine,turpentine & 6 [62] & 0.000 b  & 0.000 b  & 1.054 a  \\ \hline \multirow{2}{*}{22} & \multirow{2}{*}{2-Pentylfuran} & floral, milk-like, beauty, earthy & 6 [62] & 1.253 a [FOOTNOTE:a]Footnote a: [[https://www.flavornet.org/flavornet.html](https://www.flavornet.org/flavornet.html)]([https://www.flavornet.org/flavornet.html](https://www.flavornet.org/flavornet.html)) (accessed on 15 March and 2 April 2025). caffeine, and total tea polyphenols were significantly lower in spring teas than in autumn teas (\(p<0.05\)). These findings highlight distinct seasonal variations in the biochemical composition of teas. A total of 90 volatile compounds in white teas from two cultivars and harvest seasons were identified through HS-SPME-GC-MS analysis, which were divided into 9 chemical families. Aldehydes, alcohols, hydrocarbons, esters, and ketones were the main types of volatile compounds in white teas, among which aldehydes and alcohols were the most abundant in terms of both number and content. Spring white teas (SH-S, FD-S) contained a higher content of volatile compounds than autumn white teas (SH-A, FD-A). According to the OPLS-DA model, 52 and 57 differential volatile compounds (VIP \(>1\), \(p<0.05\), and fold change \(\geq 2\) or \(\leq\)0.5) were identified in SH-S vs. SH-A and FD-S vs. FD-A, including (\(Z\))-linalo oxide, (\(E\))-linalo oxide, styrene, phenylethyl alcohol, (\(Z\))-citral, etc. The odor active value (OAV) results indicated that 30 key differential volatile compounds (OAV \(>1\)) were determined in four groups, among which \(\beta\)-ionone, 5,6-epoxy-\(\beta\)-ionone, linalool, and (\(E\))-linalool oxide exhibited particularly high OAVs and contributed more to pekoe and floral aroma. Moreover, 18 and 19 compounds were selected as the key volatile compounds (OAV \(>1\), VIP \(>1\), \(p<0.05\), and fold change \(\geq 2\) or \(\leq\)0.5) in SH-S vs. SH-A and FD-S vs. FD-A.