## 2 Results and Discussion
### Key Aroma Compounds Identified of Three Black Teas
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**No**} & \multirow{2}{*}{**Aroma Compounds**} & \multicolumn{2}{c}{**LRI a**} & \multirow{2}{*}{**Odor**} & \multicolumn{2}{c}{**JJM**} & \multicolumn{2}{c}{**KM**} & \multicolumn{2}{c}{**DH**} & \multirow{2}{*}{**ID e**} \\  & & **DP-5 b** & **HP- Innovax c** & **Quality d** & **AI** & **FD** & **AI** & **FD** & **AI** & **FD** & **AI** & **FD** & **ID e** \\ \hline
4 & 3- & & & & & & & & & & & \\ Methylbutanal & 653 & 913 & & & & & & & & & & & \\
5 & 2-Ethylfuran & 717 & 950 & & & & & & & & & \\  & & & & & & & & & & & & \\  & & & & & & & & & & & & \\
6 & Pentanal & 694 & 975 & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & & \\
7 & Hexanal & 803 & 1077 & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & & \\  & & & & & & & & & & & \\
8 & Dimethyl disulfide & 775 & 1081 & & & & & & & & & \\  & & & & & & & & & & & \\
9 & 1-Penten-3-ol & 686 & 1156 & Green, radish & & & & & & & & \\
10 & \(\beta\)-Myrcene & 999 & 1165 & & & & & & & & \\  & & & & & & & & & & & \\
11 & 2-Heptanone & 898 & 1178 & & & & & & & & & \\  & & & & & & & & & & & \\
12 & Methyl & 925 & 1181 & & & & & & & & & \\  & hexanoate & & & & & & & & & & \\
13 & D-limonene & - & 1189 & Citrus, orange & 1.9 & 32 & 1.2 & 32 & 1.8 & 32 & RI, MS, A \\
14 & (E)-2-Hexenal & 848 & 1219 & Green, fruity & 4.2 & 64 & 5.3 & 128 & 3.9 & 32 & RI, MS, A \\
15 & 2-Pentylfuran & 994 & 1226 & & & & & & & & & \\
16 & \(\beta\)-Ocimene & 1030 & 1249 & & & & & & & & \\
17 & Styrene & 898 & 1256 & Sweet, floral & 0.3 & 4 & 0.6 & 8 & 0.5 & 4 & RI, MS, A \\
18 & 2- & & & & & & & & & & \\  & Methylpyrazine & 834 & 1264 & Popcorn, nutty & - & 64 & - & 32 & - & 32 & RI, MS, A \\
19 & 2-Pentenol & 765 & 1324 & & & & & & & & & \\
20 & 2,6- & & & & & & & & & & \\ dimethylpyrazine & 902 & 1335 & Roasted, coffee & - & 16 & - & - & - & - & RI, MS, A \\
21 & 2-Ethyl- & & & & & & & & & & & \\ pyrazine & 914 & 1337 & Nutty, musty & 3.2 & 64 & - & - & 2.9 & 64 & RI, MS, A \\
22 & 6-Methyl-5- & & & & & & & & & & & \\  & hepten-2-one & & & & & & & & & & & \\
23 & 1-Hexanol & 854 & 1346 & Oily, fruity & 3.4 & 16 & 2.1 & 32 & 1.9 & 16 & RI, MS, A \\
24 & (Z)-3-Hexen-1 & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\
25 & 1-Octen-3-ol & 976 & 1444 & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\
26 & Furfural & 831 & 1465 & Sweet, woody & 6.8 & 128 & 6.4 & 256 & 6.1 & 128 & RI, MS, A \\
27 & cis/trans- & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\
32 & 2-ethyl-1 & & & & & & & & & & \\  & hexanol & 1036 & 1481 & Citrus, sweet & 2.5 & 16 & 2.4 & 16 & 2.1 & 32 & RI, MS, A \\
29 & (E,E)-2-4- & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\
30 & Benzaldehyde & 965 & 1527 & Almond, oily & 3.5 & 32 & 5.4 & 64 & 5.3 & 32 & RI, MS, A \\
31 & Linalool & 1112 & 1541 & Citrus, floral & 6.1 & 32 & 6.8 & 64 & 7.9 & 128 & RI, MS, A \\
32 & Longifolence & 1408 & 1546 & Sweet, woody & 1.1 & 8 & - & - & 2.8 & 16 & RI, MS, A \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\
33 & Octalion-2- & 1098 & 1562 & & & & & & & & \\  & one & & & & & & & & & & \\  & & & & & & & & & & & & \\
34 & Isophorone & - & 1570 & Sweet, woody & - & 2.8 & - & - & - & RI, MS, A \\  & & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & & \\
35 & 5-methyl & 982 & 1575 & Sweet, maple & 5.6 & 64 & 4.7 & 32 & 5.1 & 64 & RI, MS, A \\  & & & & & & & & & & & & \\  & & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & & \\  & & & & & & & & & & & & \\
36 & 4-Tepinenol & 1169 & 1599 & Peppery & 1.2 & 32 & 1.9 & 32 & 6.7 & 64 & RI, MS, A \\  & & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & \\  & & & & & & & & & & & & \\  & & & & & & & & & & & & \\
37 & 5-Tepinenol & 1169 & 1599 & Peppery & 1.2 & 32 & 1.9 & 16 & 2.6 & 16 & RI, MS, A \\  & & &