## 3 Results and Discussion
### Odour-Active Compounds
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Compounds**} & \multirow{2}{*}{**Threshold**} & \multicolumn{3}{c}{**Content (mg/L)**} & \multicolumn{3}{c}{**OAV**} \\ \cline{3-10}  & & & **(mg/kg)** & **SJ** & **SW** & **DL** & **SJ** & **SW** & **DL** \\ \hline al9 & 1–Octanol & 54.000 & 0.098 \(\pm\) 0.050 & 0.026 \(\pm\) 0.002 & 0.070 \(\pm\) 0.008 & 1.8 & 0.5 & 1.3 \\ al12 & 1–Nonanol & 2.000 & 0.120 \(\pm\) 0.072 & 0.067 \(\pm\) 0.005 & 0.306 \(\pm\) 0.042 & 60.0 & 33.3 & 152.8 \\ al17 & Phenylethyl alcohol & 45.000 & 0.448 \(\pm\) 0.132 & 0.936 \(\pm\) 0.118 & — & 10.0 & 20.8 & — \\ e1 & 3–Methyl–butanoic acid ethyl ester & 6.890 & 0.129 \(\pm\) 0.006 & 0.387 \(\pm\) 0.018 & 0.067 \(\pm\) 0.007 & 18.7 & 56.2 & 9.7 \\ e2 & Pentanoic acid ethyl ester & 94.000 & 0.153 \(\pm\) 0.010 & 0.458 \(\pm\) 0.029 & 0.123 \(\pm\) 0.030 & 1.6 & 4.9 & 1.3 \\ e3 & 3–Methyl–1–butanol acetate & 3.000 & — & 0.118 \(\pm\) 0.022 & — & — & 39.3 \\ e11 & Hexanoic acid ethyl ester & 0.500 & 0.103 \(\pm\) 0.001 & 0.309 \(\pm\) 0.003 & 0.335 \(\pm\) 0.005 & 206.0 & 618.0 & 670.0 \\ e14 & Heptanoic acid ethyl ester & 170.000 & 0.067 \(\pm\) 0.020 & 0.201 \(\pm\) 0.060 & 0.270 \(\pm\) 0.053 & 0.4 & 1.2 & 1.6 \\ e19 & Octanoic acid ethyl ester & 0.100 & 0.137 \(\pm\) 0.038 & 0.411 \(\pm\) 0.114 & 1.647 \(\pm\) 0.348 & 1370.0 & 4110.0 & 1646.67 \\ e21 & 3–Methyl–butanoic acid hexyl ester & 0.150 & 0.040 \(\pm\) 0.019 & 0.120 \(\pm\) 0.057 & 0.036 \(\pm\) 0.010 & 266.7 & 800.0 & 240.0 \\ e27 & Decanoic acid ethyl ester & 20.000 & — & — & 1.233 \(\pm\) 0.336 & — & — & 61.7 \\ e37 & Benzenoacetic acid ethyl ester & 100.000 & 0.087 \(\pm\) 0.048 & 0.261 \(\pm\) 0.044 & 0.143 \(\pm\) 0.019 & 0.9 & 2.6 & 1.4 \\ e40 & Dodecanoic acid ethyl ester & 330.000 & — & — & 1.110 \(\pm\) 0.276 & — & — & 3.4 \\ e44 & Benzenpropanoic acid ethyl ester & 0.060 & — & — & 0.029 \(\pm\) 0.004 & — & — & 488.9 \\ c4 & Heptanal & 10.000 & 0.005 \(\pm\) 0.001 & 0.015 \(\pm\) 0.002 & — & 0.5 & 1.5 & — \\ c6 & Nonanal & 15.000 & 0.088 \(\pm\) 0.035 & 0.264 \(\pm\) 0.105 & 0.052 \(\pm\) 0.012 & 5.9 & 17.6 & 3.5 \\ c8 & Furfural & 100.000 & 0.034 \(\pm\) 0.003 & 0.102 \(\pm\) 0.009 & 0.444 \(\pm\) 0.090 & 0.3 & 1.0 & 4.4 \\ c10 & 5–Methyl–2–furanacarboxaldehyde & 50.000 & 0.053 \(\pm\) 0.011 & 0.159 \(\pm\) 0.053 & 0.015 \(\pm\) 0.001 & 1.1 & 3.2 & 0.3 \\ c13 & Tetradecanal & 60.000 & 0.097 \(\pm\) 0.009 & 0.284 \(\pm\) 0.069 & — & 1.6 & 4.7 & — \\ c14 & 6,10–dimethyl–5,9–Undecadien–2– & 100.00 & 0.056 \(\pm\) 0.013 & 0.169 \(\pm\) 0.058 & — & 0.5 & 1.7 & — \\  & 1–(2,6,6–Trimethyl–1,3– & & & & & & \\ c15 & cyclohexadien–1–yl)–2–buten–1– & 0.001 & — & — & 0.133 \(\pm\) 0.029 & — & — & 132,666.7 \\  & & & & & & & & \\ o3 & 4–Ethylphenol & 10.000 & 0.085 \(\pm\) 0.012 & 0.254 \(\pm\) 0.045 & — & 8.4 & 25.4 & — \\ \hline \hline \end{tabular}
\end{table} 
Table 1: OAV of odour-active components in SJ, SW and DL by GC–MS (\(n\) = 3). Five VOCs increased in SW after fermentation, including benzeneacetic acid ethyl ester (OAV 2.610), geranyl acetone (6,10-dimethyl-5,9-undecadien-2-one, OAV 1.690), heptanal (OAV 1.500), heptanoic acid ethyl ester (OAV 1.182) and furufural (OAV 1.020). 4-Ethylphenol (OAV 25.400), phenylethyl alcohol (OAV 20.800) and nonanal (OAV 17.600) were added as important VOCs of SW. Phenylethylhanol with a rose fragrance is commonly found in wine, mangosteen and other fruit wines, and has been identified as a characteristic flavour compound. [PERSON] [33] found that the relative content of phenylethanol in commercially sweet sea buckthorn wine was 7.193%. [PERSON] et al. [34] used _Hanseniaspora vavrum_ yeast fermentation to produce sea buckthorn wine, and phenylethanol accounted for 3.6% of the overall aroma, indicating that phenylethanol is a stable flavour component in sea buckthorn wine. 4-Ethylphenol is usually present in rum and whiskey, and can be used as an essence in the preparation of wine and liquor [35; 36].