## 4 Conclusions  
GC-O-MS/AEDA and quantitative experiments with FKBT and 1Y-KBT demonstrated that approximately two-thirds of the aroma volatiles were more abundant in FKBT; these included high-volatility compounds, sulfide compounds, and some floral volatiles. Ap  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Added Compounds a** & **Correct** & **Significant Level d** & **Difference** \\  & **Answers/Panelists b** & \(p\) **Value c** & **Significant Level d** & **Description** \\ \hline
3-Methyl butanal & 11/12 & 0.000 & *** & More fresh, less woody \\ Dimethyl sulfide & 10/12 & 0.001 & ** & More fresh, less woody \\ Benzeneacetaldehyde & 9/11 & 0.001 & ** & More floral, less woody \\ (E,Z)-2,6-Nonadienal & 9/11 & 0.001 & ** & More fresh, less woody \\ (E)-2-Nonenal & 7/10 & 0.020 & * & More fatty, less woody \\ Linalool & 7/11 & 0.039 & * & More floral, less woody \\ \(\beta\)-Damascenone (+50\%) & 7/11 & 0.039 & * & Sweeter, less woody \\ Methional & 7/11 & 0.039 & * & Sweeter, less woody \\ Geraniol & 7/11 & 0.039 & * & More floral, less woody \\
2-Methyl-propanal & 6/12 & 0.178 & - & - \\ Hexanal & 5/10 & 0.213 & - & - \\ Coumarin & 5/10 & 0.213 & - & - \\
2-Methyl butanal & 4/10 & 0.441 & - & - \\ Dimethyl trisulfide & 4/10 & 0.441 & - & - \\ \hline \hline \end{tabular}  
* Aroma volatiles were added in 1Y-KBT infusion individually, same as the concentrations in FKBT infusion, and \(\beta\)-damascenone was added to150% level than original. b Number of correct answers/all addition test participants.
* The statistical significance (_p_ value) of the addition test was evaluated by binomial test tables. d**, very highly significant (_p_ < 0.001); **, highly significant (0.001 \(\leq\)_p_ \(\leq\) 0.01); *, significant (0.01\(<\)_p_ \(\leq\) 0.05); and -, not significant (_p_ > 0.05).  
\end{table}
Table 4: Addition tests’ results to explain woody aroma.  
proximately one-third of the aroma volatiles were more abundant in 1Y-KBT, including benzeneacetic acid, benzoic acid, and raspberry ketone. However, most compounds with an OAV > 1 were more abundant in the FKBT infusion, with the exception of \(\beta\)-damascenone. In addition, we understood the transformation of KBT aroma through additional testing, in which we observed that the additions of several key aroma volatiles (including 3-methylbutanal, dimethyl sulfide, benzeneacetaldehyde, (E,Z)-2,6-nonadienal, and so on) weakened the woody aroma and enhanced the freshness of the KBT aroma, which indicated that controlling the storage environment to prevent the loss of these key aroma volatiles was very important to make KBT fresh.  
Conceptualization, Z.L.; formal analysis, M.T.; data curation, M.T.; writing--original draft preparation, M.T.; writing--review and editing, M.T., W.G. and W.Z. All authors have read and agreed to the published version of the manuscript.  
This study was supported by the National Key Research and Development Program of China (2021 YFD1601103); the National Key Research and Development Program of China (2017 YFD0400800); and Modern Agriculture Tea Industry System of Anhui.  
Data Availability Statement: Data is contained within the article.  
The authors express their appreciation to [PERSON] for generously providing the keeemun black tea samples.  
The authors declare no conflict of interest.