## 3 Results and Discussion
### Volatile Compounds Identified by GC-MS
In addition, benzeneacetaldehyde, homocarbhenilol, and \(\beta\)-ionone account for floral odors; (E,E)-2,4-hexadienal, benzeneacetaldehyde, and 2-pentyl-furan contribute to green odors; and some other ester compounds impart fruity odors [32] in FTL. Alcohols and esters were the major categories in the BT sample, and 16 alcohol and 11 ester volatiles were identified. The proportions of alcohols and esters from FTL to BT both increased twofold. However, the proportion of aldehydes in BT decreased to 6.69%, less than half of that in FTL. The GT sample contained aldehydes, alcohols, and ketones as the major category. Compared with FTLs, GT showed higher amounts of ketones and esters, including 11 and 10 volatiles, respectively. The proportion of ketones from FTLs and GT increased twofold, but the proportion of alkenes in GT decreased to 3.56%, about a quarter of that in FTLs. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Volatile Compounds**} & \multicolumn{2}{c}{**Relative Content (\%)**} & \multirow{2}{*}{**Odor Description \#**} \\  & & **FTL** & **BT** & **GT** \\ \hline
4 & \multicolumn{1}{c}{Carene} & ND & 0.04 & ND & Woody \\
5 & 3-[(2-methylpropan-2-yl)oxybicyclo [3.2.1]oct-3-ene & ND & ND & 0.33 & — \\
6 & Dipentene dioxide & ND & 0.13 & ND & — \\
7 & \multicolumn{1}{c}{Guadiene} & 0.79 & 0.19 & ND & — \\
**sum** & \multicolumn{1}{c}{**14.89**} & **8.42** & **3.56** \\
**Acids** & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \\
1 & Oleic Acid & 0.92 & 0.58 & 0.31 & — \\
2 & 3-Hydroxydodecanoic acid & 0.02 & ND & 0.09 & — \\
3 & cis-7-Hexadecenoic acid & 0.13 & ND & ND & — \\
4 & cis-4-(Hydrooxymethyl) cyclohexanearboxyl Acid & 0.32 & ND & ND & — \\
5 & trans-13-Oadecenoicacid & 0.22 & ND & 0.04 & — \\
6 & \multicolumn{1}{c}{Ricinoleic acid} & ND & 0.06 & ND & — \\
7 & \multicolumn{1}{c}{Linoleic acid} & ND & ND & 0.09 & Oily \\
8 & cis-5,8,11,14,17-Eicosapentaenoic acid & ND & ND & 0.02 & — \\
9 & 2-(3-acetoxy-4,4,14-trimethyl landrost-8-en-17-yl)- & 0.13 & 0.11 & 0.29 & — \\
**sup** & \multicolumn{1}{c}{**1.74**} & **0.75** & **0.84** & \\
**Alkanes** & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \\
1 & octyl-Oxirane & ND & 0.24 & ND & — \\
2 & 2-ethyl-1,1-dimethyl-Cyclopentane & ND & 0.01 & ND & — \\
3 & 1,2-15,16-Diepoxyheadcane & ND & 0.09 & ND & — \\
4 & 4-(Hexadecoxy)-2-pentadecyl-1,3-dioxane & ND & ND & 0.01 & — \\
5 & 2,6,10-trimethyl-Tetradecane & ND & ND & 0.02 & — \\
**sum** & \multicolumn{1}{c}{**0**} & \multicolumn{1}{c}{**0.34**} & **0.03** & \\
**Heterocyclics** & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \\
1 & 2-amino-5-[(2-carboxy)vinyl]-Imidiazole & 2.89 & 0.33 & 0.04 & — \\
2 & 2-pentyl-Furan & 0.87 & 0.4 & 0.34 & Bean, fruity, earthy, green, vegetable \\
**sum** & \multicolumn{1}{c}{**3.76**} & **0.73** & **0.38** & \\
**Others** & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \\
1 & \(p\)-Cymene & 1.87 & ND & ND & Aromatic \\
2 & Geranyl vinyl ether & ND & 0.6 & ND & — \\
3 & Caffeine & 4.24 & 2.18 & 0.33 & Caffeine \\
4 & 1,2-Dimristotyp-sn-glycero-3-phosphocholine & 0.09 & ND & 0.05 & — \\
**sum** & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} & \\ \hline \hline \end{tabular} \# Odor description found in the literature (Flavornet; The LRI and Odour Database); —, no odor description information was found in the literature; ND, not detectable. Others, the volatile compounds were not from aldehydes, alcohols, ketones, esters, acids, hydrocarbons, and alkenes compounds. The bold part represents the kind of the compound and the total relative content of each class.  
\end{table} 
Table 2: \(Cont.\)The content of aldehydes increased in GT, and decreased significantly in BT, because it was mainly produced by the degradation and oxidation of amino acids and reducing sugars [30].