## 3 Results and Discussion
### Analysis of Baijiu Samples
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Volatile Compounds**} & \multirow{2}{*}{**Odor Thresholds**} & \multirow{2}{*}{**Fenjiu**} & \multirow{2}{*}{**Wuliangye**} & \multirow{2}{*}{**Guotai**} & \multirow{2}{*}{**OAV**} & \multirow{2}{*}{**Concentration**} & \multirow{2}{*}{**OAV**} \\ \cline{3-3} \cline{5-7}  & & **Concentration** & & & & & \\ \hline
**Phenols** & & & & & & \\
4-Methylphenol & \(167\) & \(28.16\pm 0.91\) & 0.17 & \(1530.14\pm 8.94\) & 9.16 & \(127.14\pm 13.81\) & 0.76 \\
3-Methylphenol & \({}^{*}\) & nq & — & \(1.38\pm 0.17\) & — & \(9.61\pm 0.01\) & — \\
4-Ethylphenol & 18,900 & \(73.34\pm 5.76\) & 0.00 & \(539.69\pm 1.39\) & 0.03 & \(235.54\pm 6.55\) & 0.01 \\
4-Ethylphenol & 123 & \(54.51\pm 5.87\) & 0.44 & \(322.84\pm 5.13\) & 2.62 & \(72.88\pm 3.43\) & 0.59 \\
4-Ethyl2-methoxyphenol & 123 & \(108.8\pm 6.39\) & 0.88 & \(161.72\pm 2.08\) & 1.31 & nd & — \\
4-Hydroxy-3-methoxywhere & 209 & \(21.47\pm 0.03\) & 0.10 & nd & — & \(25.98\pm 4.19\) & 0.12 \\
4-Methyl-2-methoxyophenol & 315 & \(6.64\pm 0.18\) & 0.02 & \(43.97\pm 1.04\) & 0.14 & \(82.63\pm 1.1\) & 0.26 \\
**Tergenes** & & & & & & & \\
2-Undecanene & 6 & nq & — & \(12.67\pm 1.98\) & 2.11 & \(9.19\pm 4.05\) & 1.53 \\ \(\upmu\)-Damascenne & 0.12 & \(6.55\pm 1.71\) & 54.58 & \(9.93\pm 0.06\) & 82.75 & \(8.69\pm 0.95\) & 72.42 \\ Farnseed & \({}^{*}\) & nd & — & \(14.87\pm 1.22\) & — & \(20.04\pm 0.86\) & — \\ \(\upalpha\)-Cedrene & 6500 & \(5.88\pm 0.83\) & 0.00 & \(8.86\pm 0.2\) & 0.00 & 6.82 \(0.03\) & 0.00 \\ Carophylene & 130 & \(1.68\pm 0.24\) & 0.01 & \(4.75\pm 0.36\) & 0.04 & \(21.74\pm 0.14\) & 0.17 \\ Resoxide & \({}^{*}\) & \(1.57\pm 0.09\) & — & nd & — & — \\ Citronello & 300 & \(4.34\pm 0.59\) & 0.01 & \(3.42\pm 0.27\) & 0.01 & \(6.22\pm 0.8\) & 0.02 \\ Geramid & 120 & \(8.72\pm 0.75\) & 0.07 & \(4.12\pm 0.05\) & 0.03 & \(10.85\pm 0.31\) & 0.09 \\ Irisone & 1.3 & \(0.59\pm 0.01\) & 0.45 & \(0.69\pm 0.01\) & 0.53 & \(1.11\pm 0.04\) & 0.85 \\ Geranylacetone & 60 & \(11.82\pm 0.9\) & 0.20 & \(23.66\pm 3.94\) & 0.39 & \(46.04\pm 7.22\) & 0.77 \\ \(\upbeta\)-Cyclotetral & 3 & \(4.3\pm 1.1\) & 1.43 & \(9.45\pm 0.73\) & 3.15 & \(2.11\pm 0\) & 0.70 \\ Cineche & 0.55 & \(5.09\pm 0.55\) & 9.25 & nd & — & \(35.48\pm 4.06\) & 64.51 \\ Terpinene-4-ol & 940 & \(3.66\pm 0.13\) & 0.00 & \(3.48\pm 0.38\) & 0.00 & \(2.93\pm 0.11\) & 0.00 \\ Cedrol & 7300 & \(3.41\pm 1.77\) & 0.00 & \(19.99\pm 3.25\) & 0.00 & \(54.48\pm 1.88\) & 0.01 \\ Isophorone & 11 & \(18.09\pm 1.15\) & 1.64 & \(10.74\pm 3.55\) & 0.98 & \(14.52\pm 0.69\) & 1.32 \\ Linalool & 13.1 & \(48.07\pm 1.94\) & 3.67 & \(45.33\pm 6.54\) & 3.46 & \(77.84\pm 3.48\) & 5.94 \\
**Lactones** & & & & & & \\ \(\upgamma\)-Decalactone & 11 & \(32.1\pm 1.01\) & 0.29 & \(0.28\pm 0.03\) & 0.03 & \(9.18\pm 0.37\) & 0.83 \\ \(\upgamma\)-Dodecalactone & 60.68 & \(24.56\pm 3.45\) & 0.40 & \(42.16\pm 6.61\) & 0.69 & \(36.92\pm 1.27\) & 0.61 \\ \(\upgamma\)-Nonolactone & 91 & \(121.36\pm 1.77\) & 1.33 & \(198.03\pm 2.78\) & 2.18 & \(275.61\pm 6.94\) & 3.03 \\ \(\upgamma\)-Hexalactone & 359,000 & \(47.23\pm 1.04\) & 0.00 & \(54.51\pm 20.82\) & 0.00 & nd & — \\ \hline \hline \end{tabular}  
* * The odor threshold of the compound has not been determined or obtained from literature. nd: The compound has not been detected in this sample. nq: The compound has not been quantified in this sample.  
\end{table} 
Table 3: _Cont._In addition, this study also quantified many terpenes with very low content, most of which are below 50 ug/L. There were six types of terpene compounds in different types of Baijiu with OAVs greater than 1, which may contribute to its aroma. In the soy sauce aroma type Baijiu, the OAV of \(\beta\)-damascenone was 72.43, the OAV of eucalyptrol was 64.51, and the OAV of linalool was 5.94. The aroma thresholds were all measured in 46% ethanol/water solution. These three compounds made important aroma contributions to soy sauce aroma type Baijiu. This study quantified farnesol and rosoxide for the first time in Baijiu.