## 3 Results and Discussion
### Volatile Compounds in Foxtail millet Determined by HS-GC-IMS
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**NO.** & **Compound** & **Aroma Description** & **CAS** & **Formula** & **MW** & **RI** & **Rt** & **Dt** \\ \hline
1 & Nonanal & cucumber & 124-19-6 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 142.2 & 1109.2 & 5080.01 & 1.48022 \\
2 & 2-octral & cucumber-like & 2548-870 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 126.2 & 1054.8 & 429810 & 1.33276 \\
3 & Octanal & orange peel, green & 12413-0 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 128.2 & 1003.8 & 356.378 & 1.40870 \\
4 & Hept+2-nell & sweet, margin & 18829-55-55 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 112.2 & 952.9 & 308.696 & 1.25421 \\
5 & Benzaldehyde & bitter diamond, cherry, nut & 100-52.7 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 106.1 & 956.2 & 311.557 & 1.14497 \\
6 & Hex-2-nell & fruity, vegetable & 505-57-7 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 98.1 & 849.3 & 233.917 & 1.18241 \\
7 & Hexanal & green, grassy & 66-25-1 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 100.2 & 796.4 & 205.615 & 1.55543 \\
8 & Butanal & maly & 123-27-8 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 72.1 & 551.7 & 123.388 & 1.27561 \\
9 & Furrural & fragrant, sweet, diamond & 98-01-1 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 96.1 & 820.0 & 221.481 & 1.08335 \\
10 & 2-pentral & grassy, fruity & 17567-0 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 84.1 & 747.6 & 184.218 & 1.10518 \\
11 & Fontanal & fermented broad-like & 110-62-3 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 86.1 & 693.0 & 162.0484 & 1.42118 \\
12 & 2-methylbutanal & masty, nutty & 96-17-3 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 86.1 & 662.8 & 153.322 & 1.16667 \\
13 & 3-methylbutanal & sour, fatty, rancid & 590-86-3 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 86.1 & 662.5 & 143.542 & 1.17384 \\
14 & Oct-1-cn-3-3 & mushroom-like, rubbery & 3191-864 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 128.2 & 980.2 & 332.060 & 1.15994 \\
15 & Hexanol & green, fruity & 111-27-3 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 102.2 & 873.3 & 246.781 & 1.64594 \\
16 & Pentan-1-01 & oil, vanilla, sweet & 71-41-0 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 88.1 & 769.7 & 193.180 & 1.51874 \\
17 & 2-methylbutanal-1-ol & fermented & 137-32-6 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 88.1 & 741.3 & 181.677 & 1.46695 \\
18 & 3-methylbutanal-1-ol & oil, alcoholic, fruity & 30899-19-5 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 88.1 & 729.3 & 176.779 & 1.48937 \\
19 & 1-Propineineineh & onion & 107-03-9 & C\({}_{\rm CH}\)H\({}_{\rm O}\)S & 76.2 & 623.9 & 142.854 & 1.36308 \\
20 & Ethanol & strong alcoholic & 64-17-5 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 46.1 & 405.0 & 96.08 & 1.13026 \\
21 & Methyl+5-hepten-2-one & banana-like, floral & 110-93-0 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 126.2 & 988.6 & 339.213 & 1.17434 \\
22 & 2-Dinybo-2(3)-furanome & & 96-48-0 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 86.1 & 917.27 & 276.655 & 1.06270 \\
23 & 2-heptineh & fruity, spicy swets & 110-43-0 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 114.2 & 985.4 & 259.645 & 1.62881 \\
24 & 2-Butanone & fragrant, fruit, pleasant & 78-93-3 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 72.1 & 572.1 & 128.884 & 1.24438 \\
25 & Acetone & sweet & 67-64-1 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 88.1 & 483.6 & 104.997 & 1.12275 \\
26 & 2-Pentanone & sweety, fruity, woody & 107-87-9 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 86.1 & 681.7 & 158.439 & 1.37050 \\
27 & Buyl acrylate & grassy, fruity & 141-32-2 & C\({}_{\rm CH}\)H\({}_{\rm O}\) & 128.2 & 899.9 & 263.504 & 1.68855 \\
28 & 2-methylbutanoate & fruity, green & 868-57-5 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 116.2 & 782.4 & 198.326 & 1.18853 \\
29 & Buyl acetate & sweet, ripe banana & 123-864 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 116.2 & 802.6 & 208.924 & 1.61840 \\
30 & Enyl Acetate & fruity, sweet & 141-78-6 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 88.1 & 598.4 & 135.960 & 1.33699 \\
31 & Proxyl acetate & raspberry-like & 109-60-4 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 102.1 & 704.6 & 166.771 & 1.16583 \\
32 & 2-pentral from & fruity, grassy & 377-76-93 & C\({}_{\rm CH}\)H\({}_{\rm O}\) & 138.2 & 990.3 & 340.643 & 1.4897 \\
33 & 2-Butylfuran & mild, sweet, spicy & 4466-24-4 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 124.2 & 890.9 & 256.214 & 1.17752 \\
34 & 2-Butoylethanol & fragrance & 111-76-2 & C\({}_{\rm CH}\)H\({}_{\rm O}\)O & 118.2 & 899.4 & 263.075 & 1.20076 \\ \hline \end{tabular} Note MW: molecular mass Rt: retention index; RT: retention time; DT: data time. The aroma description of compounds were referred from The Good Scounts Company: The aroma descriptors, reported in the literature, for each volatile compound were also present.  
\end{table}