# Effects of Three Different Withering Treatments on the Aroma of White Tea
## 4 Conclusions  
The effects of SWT, IWT, and WWT on the aroma of white tea were investigated. The results of QDA and statistical analysis revealed significant differences in the aroma characteristics. The floral aroma was more pronounced in SWT, and the grassy flavor was more pronounced in WWT. A total of 202 volatile compounds were extracted by SAFE and HS-SPME and were subsequently analyzed with GC-MS. AEDA and OAV were used to select 35 key odor-active compounds. Nine odorants meeting FD factor \(\geq\) 4 and OAV \(\geq\) 1, _dimethyl sulfide_, _2-methyl-butanol_, _1-penten-3-one_, _hexanal_, _(Z)-4-heptenal_, linalool, geraniol, and trans-\(\beta\)-ionone, were identified as the main components affecting the aroma of white tea. By comparing the concentrations of odor-active compounds, the pronounced floral aroma in SWT can be primarily attributed to the action of geraniol, linalool, and _\(\beta\)-myrrene_; the pronounced grassy aroma in WWT was primarily attributed to the action of _hexanal_ and _(Z)-3-hexanol_. Geraniol, linalool, and _hexanal_ play a major role as potent odorants. The reasons for these differences were also investigated. SWT may result in the upregulation of key genes related to the synthesis and enhanced synthetase activity of GBVs, resulting in increased VTs content and a more pronounced floral aroma. WWT may have caused changes in the activity of enzymes that accelerate the synthesis and retard the degradation of certain compounds, resulting in an increase in FADVs. In white tea, sunlight withering can improve the floral aroma, and withering tank withering can enhance the grassy aroma. The experimental results provide a theoretical basis for selecting the withering method according to the flavor of white tea. This study reveals the effect of withering on the aroma of white tea. In the future, we can demonstrate the reasons for the differences more comprehensively by further studying the changes in key components, such as key genes and aroma precursors, during withering.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/foods11162502/s1](https://www.mdpi.com/article/10.3390/foods11162502/s1)]([https://www.mdpi.com/article/10.3390/foods11162502/s1](https://www.mdpi.com/article/10.3390/foods11162502/s1)), Table S1: Moisture content of the finished withering; Table S2: Volatile compounds in the three white teas produced in this study.  
Conceptualization, J.N.; formal analysis, H.W.; methodology, H.W., Y.C., W.F. and S.S.; investigation, H.W., Y.C., W.F. and S.S.; data curation, [PERSON], [PERSON] ([PERSON]) and [PERSON]; writing--original draft preparation, [PERSON]; writing--review and editing, [PERSON], [PERSON] ([PERSON]), [PERSON] ([PERSON]) and [PERSON]; visualization, [PERSON] ([PERSON]) and [PERSON]; funding acquisition, [PERSON] All authors have read and agreed to the published version of the manuscript.  
This work was supported by the National Key Research and Development Program of China (2021 YFD1601102).  
Not applicable.  
Data Availability Statement: Data is contained within the article.  
The authors declare no conflict interest.