# Compositional Analysis and Aroma Evaluation of Feijoa Essential Oils from New Zealand
## 2 Results and Discussion
### Aroma Active Compounds in Feijoa Essential Oil
The aroma active compounds were further subjected to a principle component analysis (PCA) to better evaluate the correlations among the four essential oils, as well as the associations between compounds and cultivars. As shown in Figure 5, the PCA model was successfully established, with a total of 85% variance extracted by the two principle components. The PC-1 and PC-2 expressed 65% and 20% of the variation, respectively. All feijoa cultivars, located on the right side of the plot, show high correlations with those compounds separated to the same side by PC-1. This means 15 of the 24 identified aroma active \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Name**} & \multirow{2}{*}{**CAS**} & \multirow{2}{*}{**Odor Description**} & \multicolumn{4}{c}{**Average Intensity**} \\ \cline{5-8}  & & & & **Apollo** & **Unique** & **Opal Star** & **Wiki Tu** \\ \hline \multicolumn{8}{c}{**Ester**} \\ \hline
**1** & Ethyl hexanoate & 123-66-0 & apple-like & 3.00 & 3.33 & 2.83 & 3.33 \\
**2** & (Z)-3-Hexenyl acetate & 3681-71-8 & banana-like & 2.33 & nd & nd & 2.67 \\
**3** & Methyl benzoate & 93-58-3 & feijoa-like & 5.00 & 2.33 & 3.67 & 3.67 \\
**4** & Ethyl benzoate & 93-89-0 & fresh and fruity & 4.33 & 3.33 & 3.00 & 3.67 \\
**5** & (Z)-3-Hexenyl butanoate & 16491-36-4 & grassy & 2.33 & 1.67 & 3.33 & 3.33 \\
**6** & (Z)-3-Hexenyl hexanoate & 31501-11-8 & honey-like & 3.67 & 4.00 & 4.33 & 4.67 \\
**7** & Octan-4-yl butanoate & 20286-46-8 & herbal & 2.33 & 3.00 & 3.67 & 2.00 \\
**8** & Methyl gernate & 2349-14-6 & bitter & 3.00 & 2.33 & 2.67 & 3.00 \\ \hline \multicolumn{8}{c}{**Alcohol**} \\ \hline
**9** & Linalool & 78-70-6 & floral & 4.33 & 4.00 & 3.00 & 3.67 \\
**10** & \(\alpha\)-Terpineol & 98-55-5 & fresh and minty & 4.00 & 4.00 & 4.67 & 4.33 \\
**11** & (_E_)-geraniol & 106-24-1 & fruity and peach-like & 4.00 & 4.67 & 3.67 & 4.00 \\ \hline \multicolumn{8}{c}{**Ketone**} \\ \hline
**12** & 2-Undecanone & 112-12-9 & bitter and herbal & 3.00 & 3.33 & 3.33 & 3.00 \\
**13** & 3-Octanone & 106-68-3 & mushroom-like & 4.33 & 3.67 & 4.00 & 4.00 \\ \hline \multicolumn{8}{c}{**Terpene**} \\ \hline
**14** & \(\alpha\)-Cubebene & 17699-14-8 & sweet and herbal & 4.00 & 3.33 & 4.33 & 3.67 \\
**15** & Germacrene D & 23986-74-5 & sweet, herbal, floral & 3.00 & 3.67 & 3.33 & 3.33 \\
**16** & \(\beta\)-Seliene & 17066-67-0 & woody & 2.33 & 2.33 & 2.67 & 2.00 \\
**17** & \(\delta\)-Cadineme & 483-76-1 & herbal & 2.00 & 3.33 & 4.33 & 3.67 \\
**18** & \(\beta\)-Myrcene & 123-35-3 & metallic & 5.00 & 3.33 & 2.33 & 4.33 \\
**19** & (_E_)-\(\beta\)-Ocimene & 3779-61-1 & sweet and herbal & nd & 1.67 & 1.67 & 1.67 \\
**20** & \(\beta\)-Ocimene & 13877-91-3 & mushroom-like & 2.33 & nd & 2.00 & 2.00 \\
**21** & (4\(E\),6_Z_)-allo-Ocimene & 7216-56-0 & fresh and minty & nd & nd & 3.33 & 1.67 \\ \hline \multicolumn{8}{c}{**Others**} \\ \hline
**22** & unknown (RI of 1153) & - & bitter and pungent & 4.67 & 3.67 & 3.67 & 4.67 \\
**23** & unknown (RI of 1275) & - & sweet and herbal & 3.00 & 2.67 & 2.67 & 2.33 \\
**24** & unknown (RI of 1367) & - & fruity and honey-like & 3.33 & 3.33 & 4.00 & 3.00 \\ \hline \multicolumn{8}{c}{nd--not detected.} \\ \hline
**22** & unknown (RI of 1153) & - & bitter and pungent & 4.67 & 3.67 & 3.67 & 4.67 \\
**23** & unknown (RI of 1275) & - & sweet and herbal & 3.00 & 2.67 & 2.67 & 2.33 \\
**24** & unknown (RI of 1367) & - & fruity and honey-like & 3.33 & 3.33 & 4.00 & 3.00 \\ \hline \multicolumn{8}{c}{nd—not detected.} \\ \hline
**23** & unknown (RI of 1153) & - & bitter and pungent & 4.67 & 3.67 & 3.67 & 4.67 \\
**23** & unknown (RI of 1275) & - & sweet and herbal & 3.00 & 2.67 & 2.67 & 2.33 \\
**24** & unknown (RI of 1367) & - & fruity and honey-like & 3.33 & 3.33 & 4.00 & 3.00 \\ \hline \multicolumn{8}{c}{nd—not detected.} \\ \end{tabular}
\end{table} 
Table 2: Odor active volatiles in feijoa essential oil from four cultivars. Figure 5: PCA analysis of aroma active compounds in feijoa essential oils from four feijoa cultivars.