# Effects of Different Extraction Methods on Vanilla Aroma
## 2 Results
### Investigation of the Effect of Different Extraction Methods on the Aroma Components of Vanilla Pods
#### 2.1.4 Alcoholic Extraction  
In this experiment, 35, 75 and 95% alcohol were used to extract vanilla pods, and 10, 14 and 19 volatile compounds were identified, which consisted of only aldehydes, esters, carboxylic acids, alcohols, ketones and phenols. According to Table 2, the contents of guaiacol, \(p\)-hydroxybenzaldehyde and vanillin extracted from vanilla pod with 35% alcohol were lower than those in the other two ethanolic extracts. Moreover, esters and carboxylic acids were only identified in the 75% and 95% ethanolic extractions but not in the 35% ethanolic extraction. However, only the 35% ethanolic extracts contained  
\begin{table} \begin{tabular}{l c c c c} \hline \hline \multicolumn{1}{c}{**Compounds 1**} & **RI 2** & **RI 3** & **Concentration (mg/kg) 4** & **References** \\ \hline ethyl acetate & 603 & 601 & 1.39 \(\pm\) 0.26 & [19] \\ furfural & 799 & 790 & 2.39 \(\pm\) 0.33 & [22] \\ benzaldehyde & 931 & 922 & 1.52 \(\pm\) 0.24 & [27; 28] \\ phenol & 949 & 947 & 8.86 \(\pm\) 1.37 & [29] \\ 2-pentylfuran & 975 & 968 & 0.92 \(\pm\) 0.11 & [22] \\ hexanoic acid & 955 & 975 & 3.13 \(\pm\) 1.34 & [30] \\ benzyl alcohol & 1011 & 992 & 1.27 \(\pm\) 0.09 & [28] \\ phenylacetaldehyde & 1002 & 996 & 2.28 \(\pm\) 0.39 & [31] \\ 3-octen-2-one & 1015 & 999 & 0.90 \(\pm\) 0.07 & [19] \\ limonene & 1017 & 1010 & 0.75 \(\pm\) 0.03 & [31; 32] \\ \(p\)-cresol & 1043 & 1037 & 2.90 \(\pm\) 0.28 & [22] \\
1-octanol & 1048 & 1041 & 6.76 \(\pm\) 0.69 & [31] \\ guaiacol & 1056 & 1052 & 101.58 \(\pm\) 13.92 & [22] \\ nonanal & 1074 & 1070 & 1.79 \(\pm\) 0.19 & [22] \\
2-phenylethanol & 1080 & 1073 & 1.01 \(\pm\) 0.12 & [22] \\
3,5-dimethylphenol & 1139 & 1131 & 0.40 \(\pm\) 0.21 & [33; 34] \\ octanoic acid & 1150 & 1144 & 11.21 \(\pm\) 1.14 & [19] \\ creosol & 1161 & 1157 & 5.01 \(\pm\) 0.66 & [22] \\ methyl salicate & 1166 & 1163 & 1.51 \(\pm\) 0.13 & [22; 31] \\
3-phenyl-1-propanol & 1201 & 1193 & 0.42 \(\pm\) 0.03 & [19] \\ methyl nonanoate & 1205 & 1195 & 0.69 \(\pm\) 0.32 & [19] \\ anisaldehyde & 1212 & 1210 & 0.98 \(\pm\) 0.04 & [22] \\ chavicol & 1223 & 1218 & 0.54 \(\pm\) 0.02 & [19] \\ cinnmaldehyde & 1239 & 1229 & 0.85 \(\pm\) 0.09 & [19] \\ nonanoic acid & 1247 & 1255 & 58.74 \(\pm\) 7.10 & [19] \\ (\(E\))-methyl cinnamate & 1281 & 1268 & 1.39 \(\pm\) 0.04 & [33; 34] \\ \(p\)-vinylguaiacol & 1280 & 1280 & 9.91 \(\pm\) 2.42 & [22] \\
2,4-decaional & 1288 & 1284 & 4.10 \(\pm\) 0.81 & [33; 34] \\ \(p\)-hydroxybenzaldehyde & 1315 & 1313 & 1.98 \(\pm\) 0.22 & [19; 22] \\ methyl anisate & 1336 & 1337 & 1.41 \(\pm\) 0.15 & [33; 34] \\ decaponic acid & 1344 & 1341 & 7.43 \(\pm\) 2.91 & [19] \\ (\(Z\))-methyl cinnamate & 1356 & 1349 & 12.45 \(\pm\) 3.14 & [30] \\ vanillin & 1354 & 1358 & 196.36 \(\pm\) 40.91 & [28] \\ \(\alpha\)-copenae & 1373 & 1380 & 1.46 \(\pm\) 0.33 & [35; 36] \\ undecanoic acid & 1445 & 1434 & 3.41 \(\pm\) 0.74 & [33; 34] \\
2,4-di-tert-butylphenol & 1494 & 1484 & 2.10 \(\pm\) 0.14 & [33; 34] \\ butylated hydroxytoluene & 1488 & 1491 & 2.64 \(\pm\) 0.23 & [33; 34] \\ lauritz acid & 1566 & 1535 & 16.59 \(\pm\) 5.68 & [19] \\ hexadecane & 1600 & 1600 & 1.54 \(\pm\) 0.60 & [19] \\ trideanoic acid & 1645 & 1629 & 2.57 \(\pm\) 0.65 & [33; 34] \\ cadalene & 1653 & 1660 & 2.51 \(\pm\) 0.52 & [19] \\ heptadecane & 1700 & 1700 & 3.12 \(\pm\) 0.19 & [19] \\ myristic acid & 1739 & 1731 & 21.56 \(\pm\) 4.89 & [33; 34] \\
1-octadecene & 1788 & 1757 & 3.49 \(\pm\) 2.35 & [33; 34] \\ octadecane & 1800 & 1800 & 4.03 \(\pm\) 0.31 & [19] \\
6,10,14- & & & & \\ trimethylpentadecan-2- & 1817 & 1817 & 7.08 \(\pm\) 0.86 & [33; 34] \\ one & & & & \\ pentadecanoic acid & 1823 & 1823 & 16.00 \(\pm\) 3.85 & [33; 34] \\ nonadecane & 1900 & 1900 & 24.01 \(\pm\) 11.20 & [19] \\ methyl palmitate & 1909 & 1926 & 3.81 \(\pm\) 0.99 & [19] \\ palmitic acid & 1968 & 1962 & 90.12 \(\pm\) 28.34 & [33; 34] \\ eicosane & 2000 & 2000 & 7.04 \(\pm\) 2.43 & [28] \\ \hline \hline \end{tabular}  1
[FOOTNOTE:1]Footnote 1: footnotetext: Tentatively identification of components based on GC-MS library ([PERSON] 7\(\mathsf{n_{h}}\)).