## 3 Results and Discussion
### Identification of Volatile Compounds in Six Citrus EOs

Table 1: Concentration (mean \(\pm\) standard deviation, mg/mL) of volatile compounds in six citrus essential oils (EOs) by GC-MS.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & **Compounds** & **CAS** & **RI \({}^{1}\)** & \multicolumn{4}{c}{**HYEO**} & \multicolumn{4}{c}{**GFEO**} \\ \cline{3-10}  & & & **CP** & **MADH** & **SCC** & **CP** & **MADH** & **SCC** \\ \hline \multicolumn{2}{c}{Sesquierpenes} & & & & & & & & \\ \hline
1 & \(\delta\)-Elemene & 20307-84-0 & 1339 & 7.339 \(\pm\) 0.37 & 3.396 \(\pm\) 0.371 & 0.457 \(\pm\) 0.065 & - & - & - \\ \hline
2 & \(\alpha\)-Copane & 3856-25-5 & 1376 & 2.214 \(\pm\) 0.061 & 1.358 \(\pm\) 0.158 & 0.263 \(\pm\) 0.049 & 2.489 \(\pm\) 0.082 & 2.065 \(\pm\) 0.018 & 0.324 \(\pm\) 0.028 \\ \hline
3 & \(\beta\)-Cubebene & 13744-15-5 & 1389 & 1.261 \(\pm\) 0.096 & 0.660 \(\pm\) 0.055 & 0.093 \(\pm\) 0.020 & 1.545 \(\pm\) 0.065 & 0.926 \(\pm\) 0.021 & 0.109 \(\pm\) 0.025 \\ \hline
4 & \(\beta\)-Elemene & 515-13-9 & 1391 & 3.687 \(\pm\) 0.257 & 2.164 \(\pm\) 0.346 & 0.216 \(\pm\) 0.035 & - & - & 0.033 \(\pm\) 0.006 \\ \hline
5 & \(\beta\)-Ylangene & 20479-06-5 & 1421 & 0.187 \(\pm\) 0.019 & 0.122 \(\pm\) 0.013 & - & - & - & - \\ \hline
6 & Caryophyllene & 87-44-5 & 1418 & 1.394 \(\pm\) 0.042 & 0.730 \(\pm\) 0.076 & 0.133 \(\pm\) 0.016 & 3.993 \(\pm\) 0.103 & 2.455 \(\pm\) 0.009 & 0.522 \(\pm\) 0.039 \\ \hline
7 & \(\gamma\)-Elemene & 29873-99-2 & 1433 & 1.831 \(\pm\) 0.205 & 1.133 \(\pm\) 0.250 & 0.209 \(\pm\) 0.029 & - & - & - \\ \hline
8 & \(\beta\)-Copane & 18252-44-3 & 1432 & - & - & 0.017 \(\pm\) 0.006 & - & - & 0.007 \(\pm\) 0.001 \\ \hline
9 & \(\alpha\)-Guaiene & 3691-12-1 & 1440 & 0.271 \(\pm\) 0.007 & 0.119 \(\pm\) 0.012 & 0.012 \(\pm\) 0.002 & 0.036 \(\pm\) 0.004 & - & 0.010 \(\pm\) 0.001 \\ \hline
10 & _cis_-\(\beta\)-Farnesene & 28973-97-9 & 1444 & 2.829 \(\pm\) 0.123 & 0.968 \(\pm\) 0.105 & 0.199 \(\pm\) 0.026 & 0.056 \(\pm\) 0.002 & - & 0.009 \(\pm\) 0.001 \\ \hline
11 & Humulene & 6753-98-6 & 1454 & 0.998 \(\pm\) 0.033 & 0.554 \(\pm\) 0.052 & 0.098 \(\pm\) 0.012 & 0.550 \(\pm\) 0.012 & 0.367 \(\pm\) 0.009 & 0.086 \(\pm\) 0.005 \\ \hline
12 & \(\alpha\)-Muurrolen & 15747-72-0 & 1463 & - & - & - & - & 0.004 \(\pm\) 0.001 \\ \hline
13 & Isocadinene & 16729-00-3 & 1481 & - & - & - & - & - & 0.007 \(\pm\) 0.002 \\ \hline
14 & \(\gamma\)-Muurrolen & 30021-74-0 & 1477 & - & - & - & - & - & 0.013 \(\pm\) 0.003 \\ \hline
15 & Germacrene D & 029386-74-5 & 1481 & 44.294 \(\pm\) 1.579 & 19.866 \(\pm\) 1.847 & 3.443 \(\pm\) 0.814 & 1.053 \(\pm\) 0.047 & 0.622 \(\pm\) 0.001 & 0.124 \(\pm\) 0.008 \\ \hline
16 & \(\beta\)-Selinene & 17066-67-0 & 1486 & - & - & - & - & - & 0.007 \(\pm\) 0.002 \\ \hline
17 & Valenene & 4630-07-3 & 1492 & - & 0.294 \(\pm\) 0.067 & 0.031 \(\pm\) 0.003 & - & - & 0.008 \(\pm\) 0.007 \\ \hline
18 & Bicyclogermacene & 24703-35-3 & 1495 & 3.865 \(\pm\) 0.134 & 2.000 \(\pm\) 0.198 & 0.298 \(\pm\) 0.028 & 0.432 \(\pm\) 0.017 & 0.319 \(\pm\) 0.005 & 0.068 \(\pm\) 0.004 \\ \hline
19 & \(\alpha\)-Muurrolenen & 10208-80-7 & 1499 & - & - & - & 0.126 \(\pm\) 0.002 & 0.082 \(\pm\) 0.009 & 0.028 \(\pm\) 0.005 \\ \hline
20 & \(\alpha\)-Bulinesene & 3691-11-0 & 1505 & 0.380 \(\pm\) 0.034 & - & - & 0.114 \(\pm\) 0.054 & 0.073 \(\pm\) 0.008 & 0.014 \(\pm\) 0.002 \\ \hline
21 & \(\alpha\)-Farnesene & 502-61-4 & 1508 & - & 0.526 \(\pm\) 0.060 & 0.050 \(\pm\) 0.005 & - & - & - \\ \hline
22 & \(\gamma\)-Cadinene & 39029-41-9 & 1513 & - & - & 0.117 \(\pm\) 0.025 & - & - & 0.009 \(\pm\) 0.003 \\ \hline
23 & \(\beta\)-Cadinene & 523-47-7 & 1518 & 1.743 \(\pm\) 0.062 & 1.034 \(\pm\) 0.192 & 0.276 \(\pm\) 0.012 & 1.893 \(\pm\) 0.108 & 1.200 \(\pm\) 0.030 & 0.322 \(\pm\) 0.061 \\ \hline
24 & Calamenene & 483-77-2 & 1523 & - & - & - & - & 0.016 \(\pm\) 0.005 \\ \hline
25 & \(\beta\)-Sesquierbellandrene & 20307-83-9 & 1524 & 0.237 \(\pm\) 0.021 & 0.103 \(\pm\) 0.023 & 0.013 \(\pm\) 0.002 & - & - & - \\ \hline
26 & 1,4-Cadinadiene & 16728-99-7 & 1532 & - & - & 0.227 \(\pm\) 0.054 & - & - & 0.011 \(\pm\) 0.003 \\ \hline
27 & \(\alpha\)-Cadinene & 24406-05-1 & 1538 & - & - & 0.007 \(\pm\) 0.001 & - & - & 0.003 \(\pm\) 0.001 \\ \hline
28 & \(\alpha\)-Calacorne & 21391-99-1 & 1542 & - & - & - & - & - & 0.004 \(\pm\) 0.002 \\ \hline
29 & Germacrene B & 15423-57-1 & 1556 & 7.904 \(\pm\) 0.271  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Compounds**} & \multicolumn{2}{c}{**CAS**} & \multicolumn{2}{c}{**RI \({}^{\ddagger}\)**} & \multicolumn{2}{c}{**HYEO**} & \multicolumn{2}{c}{**GFEO**} \\ \cline{3-10}  & & & **CP** & **MADH** & **SCC** & **CP** & **MADH** & **SCC** \\ \hline \multicolumn{10}{c}{Alcohols} \\ \hline
1 & _cis_-3-Heexemel & 928-96-1 & 861 & - & 0.034 \(\pm\) 0.003 & 0.002 \(\pm\) 0.000 & - & - & - \\ \hline
2 & (E)-2-Heexem-1-ol & 928-95-0 & 862 & - & - & - & - & 0.018 \(\pm\) 0.005 & - \\ \hline
3 & 1-Hexanol & 111-27-3 & 870 & - & 0.095 \(\pm\) 0.005 & - & - & 0.054 \(\pm\) 0.009 & - \\ \hline
4 & 1-Octanol & 111-87-5 & 1071 & - & 0.174 \(\pm\) 0.003 & 0.007 \(\pm\) 0.001 & 0.599 \(\pm\) 0.036 & 3.700 \(\pm\) 0.042 & 0.144 \(\pm\) 0.026 \\ \hline
5 & Linalool & 78-70-6 & 1107 & - & 0.327 \(\pm\) 0.040 & 0.028 \(\pm\) 0.004 & 0.918 \(\pm\) 0.038 & 2.403 \(\pm\) 0.020 & 0.198 \(\pm\) 0.015 \\ \hline
6 & (E)-p-2-8-1- & 7212-40-0 & 1123 & - & 0.107 \(\pm\) 0.009 & - & 0.136 \(\pm\) 0.056 & 0.187 \(\pm\) 0.029 & - \\ \hline
7 & 1-Nonanol & 143-08-8 & 1165 & - & - & 0.008 \(\pm\) 0.002 & - & 0.149 \(\pm\) 0.004 & 0.014 \(\pm\) 0.002 \\ \hline
8 & Terpinen-4-ol & 562-74-3 & 1177 & - & 0.235 \(\pm\) 0.042 & 0.011 \(\pm\) 0.002 & - & 0.250 \(\pm\) 0.017 & 0.024 \(\pm\) 0.003 \\ \hline
9 & _a_-Terpineol & 98-55-5 & 1189 & - & 0.192 \(\pm\) 0.024 & 0.013 \(\pm\) 0.002 & 0.494 \(\pm\) 0.010 & 1.515 \(\pm\) 0.019 & 0.124 \(\pm\) 0.015 \\ \hline
10 & _cis_-Carveol & 1197-06-4 & 1229 & - & 0.137 \(\pm\) 0.024 & 0.003 \(\pm\) 0.000 & 0.060 \(\pm\) 0.018 & 0.461 \(\pm\) 0.009 & 0.053 \(\pm\) 0.011 \\ \hline
11 & Nerol & 106-25-2 & 1228 & - & 0.095 \(\pm\) 0.007 & 0.011 \(\pm\) 0.002 & 0.042 \(\pm\) 0.006 & 0.352 \(\pm\) 0.018 & 0.024 \(\pm\) 0.004 \\ \hline
12 & Citronell & 106-22-9 & 1241 & - & 0.257 \(\pm\) 0.032 & 0.020 \(\pm\) 0.003 & - & 0.335 \(\pm\) 0.019 & 0.033 \(\pm\) 0.003 \\ \hline
13 & Geraniol & 106-24-1 & 1255 & - & 0.044 \(\pm\) 0.004 & 0.002 \(\pm\) 0.000 & 0.066 \(\pm\) 0.009 & 0.506 \(\pm\) 0.016 & 0.038 \(\pm\) 0.003 \\ \hline
14 & 1-Decanol & 112-30-1 & 1273 & - & 0.126 \(\pm\) 0.010 & 0.018 \(\pm\) 0.002 & - & 0.503 \(\pm\) 0.015 & 0.068 \(\pm\) 0.005 \\ \hline
15 & Elemol & 639-99-6 & 1549 & 0.264 \(\pm\) 0.017 & 0.290 \(\pm\) 0.045 & 0.037 \(\pm\) 0.002 & 0.241 \(\pm\) 0.014 & 0.313 \(\pm\) 0.015 & 0.030 \(\pm\) 0.007 \\ \hline
16 & _trans_-Nerololidid & 40716-66-3 & 1563 & - & - & - & 0.083 \(\pm\) 0.013 & 0.070 \(\pm\) 0.001 & 0.015 \(\pm\) 0.004 \\ \hline
17 & Germacrene & 198991-79-6 & 1574 & 0.513 \(\pm\) 0.023 & 0.190 \(\pm\) 0.018 & - & 0.128 \(\pm\) 0.015 & 0.084 \(\pm\) 0.007 & 0.007 \(\pm\) 0.001 \\ \hline
18 & Isospathuelon & 88395-46-4 & 1638 & 0.144 \(\pm\) 0.015 & 0.291 \(\pm\) 0.031 & 0.018 \(\pm\) 0.000 & - & - & - \\ \hline
19 & _T_-Murorold & 19912-62-0 & 1642 & - & 0.117 \(\pm\) 0.057 & 0.020 \(\pm\) 0.003 & - & - & 0.003 \(\pm\) 0.001 \\ \hline
20 & _a_-Cadinol & 481-34-5 & 1653 & 0.094 \(\pm\) 0.026 & 0.372 \(\pm\) 0.048 & 0.043 \(\pm\) 0.012 & - & - & - \\ \hline
21 & _\(\beta\)_-Eudesmol & 473-15-4 & 1649 & - & - & - & - & - & 0.011 \(\pm\) 0.005 \\ \hline
22 & Intermedeol & 6168-59-8 & 1667 & 0.274 \(\pm\) 0.021 & 0.460 \(\pm\) 0.087 & 0.027 \(\pm\) 0.004 & - & - & - \\ \hline
23 & Shycbunol & 35727-45-8 & 1699 & - & - & - & 0.047 \(\pm\) 0.006 & 0.047 \(\pm\) 0.007 & 0.005 \(\pm\) 0.001 \\ \hline
24 & (2\(\beta\)_6_E)-Farnesol & 4602-84-0 & 1713 & - & - & - & 0.118 \(\pm\) 0.016 & 0.131 \(\pm\) 0.006 & 0.008 \(\pm\) 0.004 \\ \hline Esters & & & & & & & & \\ \hline
1 & Octyl acetate & 112-14-1 & 12111 & 0.309 \(\pm\) 0.002 & 0.246 \(\pm\) 0.027 & 0.023 \(\pm\) 0.009 & 0.361 \(\pm\) 0.012 & 0.495 \(\pm\) 0.003 & 0.037 \(\pm\) 0.008 \\ \hline
2 & Bornyl acetate & 76-49-3 & 1285 & - & - & 0.011 \(\pm\) 0.003 & - & - & - \\ \hline
3 & _cis_-Carryyl acetate & 1134-95-8 & 1337 & 0.074 \(\pm\) 0.006 & 0.324 \(\pm\) 0.054 & 0.008 \(\pm\) 0.003 & - & - & 0.005 \(\pm\) 0.001 \\ \hline
4 & _a_-Terpinyl acetate & 80-26-2 & 1350 & - & - & - & 0.044 \(\pm\) 0.011 & 0.076 \(\pm\) 0.008 & 0.005 \(\pm\Terpenes (>90%) were the most abundant volatile compounds in citrus EOs, including monoterpenes and sesquiterpenes.