## 3 Results
### Identification of Volatile Organic Compounds by HS-SPME-GC-Ms
#### 3.4.1 Characterization of VOCs in Different Fermentation Groups
The ester content in the SY, ET008-c54, EC-1118, and NM-8 fermentation groups was 2640.94 ug/L-1, 2345.69 ug/L-1,  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Compound** & **RI \({}^{\bullet}\)** & **Identification \({}^{\bullet}\)** & \multicolumn{4}{c}{**Concentration (ug L-1) \({}^{\bullet}\)**} & **Threshold** & **Aroma** \\ \cline{3-8}  & & & **SY** & **EC-1118** & **NM-8** & **ET008-c54** & **(ug L-1) \({}^{\bullet}\)** & **Description \({}^{\circ}\)** \\ \hline \multirow{2}{*}{Phenyllehenyl Alcohol} & \multirow{2}{*}{1894} & \multirow{2}{*}{MS, RI} & 678.27 \(\pm\) 40.71 & 617.67 \(\pm\) 36.58 b & 367.15 \(\pm\) 7.5 c & 714.4 \(\pm\) 6.66 a & 564.23 & floral, fruit, \\   Isobutanol & 1076 & MS, RI & 40.73 \(\pm\) 2.57b & 49.65 \(\pm\) 3.25 b & 67.85 \(\pm\) 60.2 a & 61.82 \(\pm\) 1.23 a & 250,000 & alcohol, apple \\  2-Ethylehanol & 1474 & MS, RI & 16.85 \(\pm\) 0.52d & 23.16 \(\pm\) 0.24 c & 24.92 \(\pm\) 0.16b & 44.12 \(\pm\) 0.92 a & 300 & citrus, green, \\   Nerchildot & 2025 & MS, RI & 13.37 \(\pm\) 0.96a & 10.22 \(\pm\) 1.24 b & 5.68 \(\pm\) 0.12 c & 13.82 \(\pm\) 0.28 a & 250 & oil, flower, wood \\   Benzyl Alcohol & 1860 & MS, RI & 12.44 \(\pm\) 0.81b & 10.56 \(\pm\) 0.71 c & 1.569 \(\pm\) 0.33 a & 12.11 \(\pm\) 0.27 b & 159,000 & floral, fruit \\  1-Propanol & 1019 & MS, RI & 8.68 \(\pm\) 0.67 a & 5.87 \(\pm\) 0.38 b & 4.99 \(\pm\) 0.53b & 7.62 \(\pm\) 0.19 a & 250,000 & plastic \\  1-Dodecanol & 1948 & MS, RI & 6.58 \(\pm\) 1.79 a & 4.78 \(\pm\) 1.36 a & 5.13 \(\pm\) 0.35 a & 5.7 \(\pm\) 0.57 a & 1000 & fat, wax \\  1-Otanol & 1542 & MS, RI & 4.58 \(\pm\) 0.06 a & ND & 5.27 \(\pm\) 0.68 a & ND & 820 & citrus, fruit, \\  1-Ottanol & 1595 & MS, RI & 5.03 \(\pm\) 0.26 b & 4.64 \(\pm\) 0.11 b & 5.63 \(\pm\) 0.12 a & 4.89 \(\pm\) 0.09 b & NF & fresh, xenon, \\  (R)+(c)irondl & 1748 & MS, RI & ND & ND & ND & 1.95 \(\pm\) 0.49 a & 40 & floral \\ \hline \multirow{2}{*}{1-Nounenol} & \multirow{2}{*}{1643} & \multirow{2}{*}{MS, RI} & 1.85 \(\pm\) 0.99 b & 2.05 \(\pm\) 0.06 ab & 1.68 \(\pm\) 0.14 b & 2.35 \(\pm\) 0.31 a & 310 & fat, floral, green \\   Lininol & 1533 & MS, RI & 1.09 \(\pm\) 0.24 b & 1.05 \(\pm\) 0.12 b & ND & 2.23 \(\pm\) 0.07 a & 6 & floral, flower, \\  1-Headaned & 2351 & MS, RI & ND & 2.97 \(\pm\) 0.61 a & 3.98 \(\pm\) 0.94 a & 3.93 \(\pm\) 0.62 a & 1100 & flower, wax \\   Cs-OtConnell & 1638 & MS, RI & 2.39 \(\pm\) 0.05 b & 2.07 \(\pm\) 0.70 c & ND & 3.15 \(\pm\) 0.15 a & NF & ND \\  1-Butanol & 1129 & MS, RI & 1.11 \(\pm\) 0.08 ab & 1.07 \(\pm\) 0.08 b & 1.29 \(\pm\) 0.09 a & 0.73 \(\pm\) 0.02 c & 459.2 & alcohol, fermented, fruit \\  1-Octeno-3-OI & 1426 & MS, RI & 0.83 \(\pm\) 0.01 a & ND & 0.77 \(\pm\) 0.03 c & 0.64 \(\pm\) 0.4 d & 20 & floral, green, herb \\  2208 & MS, RI & 2.59 \(\pm\) 0.03 a & 2.81 \(\pm\) 0.76 a & 1.03 \(\pm\) 0.03 b & 2.82 \(\pm\) 0.1 a & 20 & floral, oil, wet \\  1-Ottaface & 2351 & MS, RI & 2.49 \(\pm\) 0.01 a & ND & 1.06 \(\pm\) 0.01 b & ND & NF & oil \\  (2)-2-Dinelonly-5,7- & \multirow{2}{*}{1638} & \multirow{2}{*}{MS, RI} & \multirow{2}{*}{ND} & \multirow{2}{*}{ND} & \multirow{2}{*}{2.78 \(\pm\) 0.04 a} & ND & NF & NF \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & \\  & & & & & & & & & & \\  &2120.21 \(\mathrm{\SIUnitSymbolMicro g}\)\(\cdot\)L\({}^{-1}\), and 1796.53 \(\mathrm{\SIUnitSymbolMicro g}\)\(\cdot\)L\({}^{-1}\), respectively, accounting for 35.30%-38.40% of the total VOCs. Among the esters, ethyl esters were predominant, constituting 95.20%-96.31% of the ester compounds. Compounds such as ethyl octanoate (apricot, banana aroma), ethyl laurate (floral, green apple aroma), and ethyl hexanoate (banana aroma) were present in significantly higher concentrations in the SY fermentation group than in the other groups. This likely contributed to a more pronounced fruity and floral aroma in the GAB fermented with SY, compared to the samples fermented with the other three _S.