## 3 Results and Discussion
### Odor Activity Values
The twenty volatile compounds with the highest OAVs were used to conduct the aroma shape of Taiping Houkui green tea, and the results suggested that these volatiles might be the key odorants in Taiping Houkui green tea [36]. In the present study, the top twenty odorants with OAVs \(\geq 1\) in the final XYMJ green tea were used to construct the aroma shape of each processed sample during the XYMJ green tea manufacturing (Figure 8). The result showed that the seven processed samples could be divided into two groups consistent with PCoA and HCA analyses, suggesting that fixing was the crucial process step for the aroma formation of XYMJ green tea. \begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline
**Compounds \({}^{*}\)** & \
\begin{tabular}{c} **Threshold** \\ **(ug/L) \#** \\ \end{tabular} & **Odor Type \#** &
\begin{tabular}{c} **Tea** \\ **Shools** \\ \end{tabular} & **Spreading** & **Fixing** & **Rolling** & **Scattering** & **Shaping** & **Drying** \\ \hline trans-Nerololidad \({}^{c}\) & 0.25 & Floral & 15,070.2 & 17,689.4 & 10,692.2 & 7875.2 & 9909.2 & 11,838.2 & 10,199.4 \\ Geranylacetone \({}^{d}\) & 0.06 & Floral & 4056.3 & 4197.5 & 2781.8 & 2652.8 & 3355.0 & 3950.2 & 3436.5 \\ Nonanal \({}^{a}\) & 1.0 & Floral & 20,634.3 & 18,717.2 & 2701.0 & 3132.8 & 3065.1 & 3292.8 & 3190.1 \\ (+)-S-d'enance & 1.5 & Woody & 957.2 & 909.6 & 1466.0 & 1397.1 & 1777.6 & 1971.3 & 1881.0 \\ Linalo \({}^{c}\) & 6.0 & Floral & 7564.9 & 605.6 & 710.8 & 863.1 & 813.4 & 908.8 & 838.0 \\ (Z)-Jasmone \({}^{a}\) & 1.9 & Floral & 950.6 & 1752.8 & 528.5 & 494.1 & 458.7 & 523.2 & 465.6 \\ cis-3-Hexenyl butyrate \({}^{a}\) & 0.7 & Fruity & 1917.0 & 1136.6 & 666.8 & 459.8 & 273.9 & 255.9 & 220.6 \\ cis-3-Hexenyl hexanoate \({}^{*}\) & 16 & Green & 431.0 & 298.7 & 333.0 & 223.1 & 217.4 & 219.9 & 189.0 \\ Methyl jasmonate \({}^{a}\) & 3.0 & Floral & 224.5 & 290.3 & 122.4 & 131.3 & 152.3 & 230.2 & 125.1 \\ \(\beta\)-Gcmene \({}^{c}\) & 10 & Floral & 1014.5 & 1066.9 & 57.3 & 76.0 & 82.7 & 96.5 & 92.4 \\ \(\beta\)-Myronene \({}^{c}\) & 42 & Woody & 636.1 & 696.8 & 28.8 & 44.7 & 45.0 & 53.2 & 49.9 \\ Coquene \({}^{c}\) & 7.0 & Floral & 9.5 & 7.0 & 33.3 & 27.0 & 37.9 & 40.4 & 43.2 \\ cis-6-Farmesene \({}^{c}\) & 87 & Floral & 17.4 & 12.0 & 20.9 & 15.8 & 28.8 & 31.7 & 35.0 \\ D-Limonene \({}^{c}\) & 10 & Fruity & 234.2 & 238.9 & 20.6 & 26.1 & 32.4 & 33.6 & 33.8 \\ (+)-G-Colemene \({}^{c}\) & 187 & Floral & 360.7 & 374.0 & 16.0 & 24.4 & 25.6 & 30.3 & 29.5 \\ Dhydrocinolide \({}^{d}\) & 2.1 & Musk & 30.5 & 35.9 & 15.1 & 14.9 & 24.8 & 31.7 & 23.0 \\ M-Cymene \({}^{c}\) & 114 & Floral & 68.5 & 69.1 & 10.6 & 10.9 & 13.4 & 12.9 & 13.2 \\ (Z)-p-e-Farmesene \({}^{c}\) & 87 & Floral & 7.7 & 6.3 & 10.6 & 7.8 & 11.7 & 13.2 & 13.0 \\ Methyl salicylate \({}^{b}\) & 40 & Green & 279.0 & 266.9 & 8.8 & 12.6 & 7.0 & 8.5 & 6.8 \\ Geraniol \({}^{c}\) & 53 & Fruity & 70.9 & 82.5 & 2.5 & 4.7 & 5.3 & 7.4 & 5.5 \\ Phytol acetate \({}^{a}\) & 750 & Floral & 0.9 & 1.8 & 2.0 & 2.8 & 4.0 & 5.7 & 4.4 \\ trans-furan Ianalol oxide \({}^{c}\) & 190 & Floral & 31.5 & 34.9 & 3.0 & 3.5 & 2.9 & 3.6 & 3.1 \\ cis-3-Hexenyl valerate \({}^{a}\) & 60 & Fruity & 11.0 & 4.2 & 4.5 & 3.0 & 3.0 & 3.0 & 2.6 \\ (+)-\(\alpha\)-Terpineol \({}^{c}\) & 330 & Floral & 2.6 & 2.6 & 1.2 & 1.1 & 1.4 & 1.7 & 1.7 \\ \hline \hline \end{tabular}  
* \({}^{a}\): fatty acid derived volatiles (FADVs), \({}^{b}\): amino acid derived volatiles (AADVs), \({}^{c}\): volatile terpenes (VTs), \({}^{d}\): carotenoid derived volatiles (CDVs), and \({}^{e}\): others. # The threshold values and the odor type were based on the previous literature [11,19,29,36,38,39,40].  
\end{table} 
Table 2: Volatile compounds with OAVs \(>1\) in the processed XYMJ green tea samples.