# Analysis of Volatile Components in Different _Ophiocordyceps sinensis_ and Insect Host Products
## 2 Results and Discussion
### Major Compounds in Different Products  
The numbers and percentage contents of volatile compounds in samples are of marked differences. Alkanes are the dominant volatile compounds in all samples. Alkane is also the class with the largest number in all samples (Figure 2). The top five compounds in the concentration of each sample are shown in Table 3.  
Figure 2: The number (**A**) and relative content (**B**) of volatile compounds of each class in different products. Note: For descriptions of W, A, A0, A1, A2, A3, FB, FC20d, FC40d, FC60d, FC80d, FC100d, Tx-LU, Tx-LI, Tx-PU, and Tx-PI, please refer to Table 1). \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{3}{*}{**Sample**} & \multicolumn{4}{c}{**Top Five Compounds**} \\ \cline{2-10}  & \multicolumn{2}{c}{**1**} & \multicolumn{2}{c}{**2**} & \multicolumn{2}{c}{**3**} & \multicolumn{2}{c}{**4**} & \multicolumn{2}{c}{**5**} \\ \cline{2-10}  & **Compound** & **Peak Area** & **Compound** & **Peak Area** & **Compound** & **Peak Area** & **Compound** & **Peak Area** & **Compound** & **Peak Area** \\  & **No.** & **Percentage (\%)** & **No.** & **Percentage (\%)** & **No.** & **Percentage (\%)** & **No.** & **Percentage (\%)** & **No.** & **Percentage (\%)** \\ \hline W & C24 & 11.42 & C19 & 8.24 & C39 & 6.99 & C105 & 6.98 & C17 & 4.78 \\ A & C19 & 21.12 & C34 & 8.16 & C29 & 6.47 & C76 & 5.75 & C25 & 4.31 \\ A0 & C19 & 13.94 & C20 & 10.77 & C29 & 9.82 & C31 & 8.78 & C76 & 6.96 \\ A1 & C19 & 20.95 & C20 & 8.39 & C29 & 8.11 & C76 & 6.91 & C24 & 6.32 \\ A2 & C19 & 17.49 & C29 & 10.91 & C20 & 9.75 & C76 & 7.49 & C31 & 5.90 \\ A3 & C19 & 17.56 & C21 & 7.31 & C76 & 6.84 & C20 & 6.41 & C29 & 5.65 \\ FB & C2 & 10.80 & C19 & 8.18 & C76 & 7.11 & C14 & 5.29 & C34 & 4.23 \\ FC20d & C76 & 7.59 & C24 & 6.73 & C38 & 6.28 & C20 & 5.63 & C29 & 4.54 \\ FC40d & C24 & 9.70 & C19 & 9.40 & C38 & 8.33 & C76 & 6.91 & C61 & 5.94 \\ FC60d & C20 & 9.35 & C24 & 8.54 & C76 & 7.50 & C29 & 7.38 & C59 & 5.81 \\ FC80d & C21 & 7.69 & C19 & 7.63 & C24 & 7.56 & C76 & 6.77 & C38 & 6.72 \\ FC100d & C38 & 7.70 & C76 & 7.64 & C20 & 7.61 & C61 & 6.01 & C24 & 5.38 \\ T-LU & C24 & 56.02 & C16 & 11.27 & C23 & 3.22 & C5 & 1.57 & C34 & 1.48 \\ T-VL & C24 & 61.87 & C116 & 9.14 & C5 & 3.72 & C3 & 2.55 & C1 & 1.22 \\ T-PV & C19 & 14.60 & C29 & 11.44 & C76 & 7.15 & C31 & 5.91 & C34 & 5.71 \\ Tx-PI & C19 & 29.16 & C34 & 7.31 & C76 & 5.78 & C29 & 5.72 & C5 & 5.09 \\ \hline \hline \end{tabular} Note: C1: 3: Top-2: employing:cycle/cycle/cycle/cycle/cycle: C2: 2: methylcyclopentack: C3: eye-plane: C14: 6-ethyl: 2.6-trimethylbenzene: C17: 2.4-trimethylbenzene: C20: 2.6-trimethyladecene: C21: 6-trimethyladecene: C21: 6-trimethyladecene: C22: 2.4-trimethyldodecene: C23: 2.5-trimethyladecene: C24: 2.6-trimethyldodecene: C34: 2.6-dimethyldodecene: C38: 1.2-dimethyldodecene: C38: 1.2-dimethyldodecene: C38: 1.2-dimethyldodecene: C38: 1.2-dimethyldodecene: C39: 3.7.1-trimethyldodecan-1.0-C61: (+)-a-tetpined: C76 2.3-dimethyldodecane: C99: (-)-a-guurpinene: C108: isoledene, C116: 2.4-d-literl-butyl: 6-methyl phenol: The compounds corresponding to the compound numbers are also shown in Table 2.  
\end{table} 
Table 3: Top five compounds in concentration from different products. 2,5,6-trimethyldecane (C19) is the most abundant compound in artificial cultivated Chinese cordyceps (A, A0, A1, A2, A3) and insect pupae (Tx-PU and Tx-PI), and it is also the major compound in W, FB, and FC40d, FC80d, and FC100d (Table 3). This compound is so far detected from beneficial plants such as Irish York cabbage [28], stevia _Stevia rebaudiana_ leaves [29], an aquatic perennial herb _Limnophila indica_ extract [30], plant-based food such as chestnut and jujube honey [31], and from exhaled breath in both children with allergic asthma and control [32]. 5,6-Dihydro-6-pentyl-2\(H\)-pyran-2-one (massoia lactone) is discovered as the dominant volatile component in a fermented mycelial product of _Paecilomyces hepial_ fungus [18]. 2,5,6-trimethyldecane is the first reported dominant volatile compound in \(O\).