# Difference in Aroma Components of Black Teas Processed on Different Dates in the Spring Season
## 3 Results and Discussion
### Screening of the Key Differential Odorants Based on OAV
In summary, combined with the sensory evaluation and the differences in the total content of volatile compounds, flavor index, and OAVs, it is proposed that black teas \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Volatile Compound**} & \multirow{2}{*}{**Odor Description**} & \multicolumn{5}{c}{**OAV**} \\ \cline{3-8}  & & & **ZYQ-1** & **ZYQ-2** & **ZYQ-3** & **ZYQ-4** & **ZYQ-5** \\ \hline
1 & Naphthalene \({}^{1}\) & Pungent [32] & 6.2 & 2.7 & 6.2 & 6.8 & 4.1 \\
2 & (E)-\(\beta\)-Ocimene \({}^{1}\) & Warm, floral, herbal, sweet [34] & 115.5 & 206.3 & 223.4 & 311.8 & 205.4 \\
3 & Ocimene \({}^{1}\) & Herbal, green [15] & & 1.3 & 1.3 & 1.0 & \\
4 & \(\delta\)-Cadinene \({}^{1}\) & Herbal, woody [32] & 1.0 & 3.5 & 2.2 & 3.7 & 3.0 \\
5 & cis-Linalool oxide (furanoid) \({}^{1}\) & Fruity [15] & & & 1.3 & 1.8 & 2.0 \\
6 & trans-Linalool oxide (furanoid) \({}^{1}\) & Fruity, fresh [15] & & 1.8 & 3.3 & 3.2 & 4.0 \\
7 & Linalool \({}^{1}\) & Floral, sweet [33] & 284.6 & 278.4 & 403.6 & 586.9 & 510.7 \\
8 & Geraniol \({}^{1}\) & Rose-like, sweet [7] & 63.3 & 100.0 & 87.1 & 63.8 & 37.3 \\
9 & Nerolololid \({}^{1}\) & Floral, woody [31] & & & 1.3 & 1.4 \\
10 & 3-Methylbutanal \({}^{1}\) & Malt [31] & 4.4 & 13.1 & 8.7 & 5.7 & 17.7 \\
11 & 2-Methylbutanal \({}^{1}\) & Cocoa, almond [31] & & 3.7 & 3.5 & 2.3 & 7.9 \\
12 & Hexanal \({}^{1}\) & Green, leafy, grassy [10; 33] & 2.0 & & & & \\
13 & Benzene acetaldehyde \({}^{1}\) & Woody, sweet, honey [3; 8; 31] & 1.0 & 2.4 & 2.3 & 3.9 & 5.8 \\
14 & (E)-2-Octenal \({}^{1}\) & Fresh, cucumber-like, fatty, green [10] & 1.1 & & & & \\
15 & Nonanal \({}^{1}\) & Waxy, fresh, orange-like [10] & 13.9 & 6.3 & 6.9 & 6.7 & 15.6 \\
16 & (E)-2-Nonenal \({}^{1}\) & Watermol, cucumber-like [15] & 24.1 & 17.2 & 11.0 & 13.9 & 14.8 \\
17 & Safranal \({}^{1}\) & Woody, spicy, medicinal [33] & & & 1.1 & 1.0 & 2.8 \\
18 & (E,E)-2,4-Nonadenal \({}^{1}\) & Cucumber-like [8] & 95.9 & 56.9 & 52.6 & 40.2 & 64.2 \\
19 & \(\beta\)-Cyclotella \({}^{1}\) & Herbal, clean, rose-like, fruity [33] & & & 1.2 & 0.9 & 1.6 \\
20 & \(\beta\)-Damascenone \({}^{1}\) & Fruity, apple-like [7] & 392.7 & 558.3 & 569.2 & 593.7 & 469.0 \\
21 & \(\alpha\)-Ionone \({}^{1}\) & Woody, violet-like, floral [8; 33] & 4.2 & 2.9 & 2.0 & 1.6 & 1.8 \\
22 & \(\beta\)-Ionone \({}^{1}\) & Woody, violet, floral [7; 33] & 725.5 & 561.1 & 560.0 & 576.8 & 657.9 \\
23 & Methyl salicate \({}^{1}\) & Vanilla flavor [3; 15] & 1.9 & 2.9 & 3.3 & 2.8 & 2.3 \\
24 & cis-3-Heresenyl isovalerate \({}^{1}\) & Fresh, green [15] & 21.7 & 18.2 & 20.2 & 19.0 & 19.8 \\
25 & Dimethyl sulfide \({}^{1}\) & Cabbage, sulfur, corn, molasses [31] & 3.0 & 7.2 & 4.8 & 4.5 & 6.0 \\ Sum & & 1762.1 & 1844.4 & 1975.2 & 2252.5 & 2055.1 \\ Group I & & 145.1 & 86.0 & 80.0 & 70.4 & 101.1 \\ Group II & & 1617.0 & 1758.3 & 1895.2 & 2182.1 & 1954.0 \\ Group II/Group I & & 11.1 & 20.4 & 23.7 & 31.0 & 19.3 \\ \hline \hline \end{tabular} Note: I means that this volatile compound has an adverse affect on black tea aroma, and II means that this volatile compound is beneficial for black tea aroma.  
\end{table} 
Table 3: Odor descriptions and odor active values (OAVs) of identified volatile compounds. produced around April 15 th will have relatively better aroma quality compared with those produced on other dates in the spring season (Table 1).