## 2 Results
### PCA Analysis at Different Ripening Stage of Two Banana Varieties
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Compounds**} & \multirow{2}{*}{**Fenjiao**} & \multirow{2}{*}{**Brazilian**} & \multirow{2}{*}{**Fenjiao**} & \multirow{2}{*}{**Brazilian**} & \multirow{2}{*}{**Fenjiao**} & \multirow{2}{*}{**Brazilian**} & \multirow{2}{*}{**Fenjiao**} & \multirow{2}{*}{**Brazilian**} \\ \hline Total (Esters) & 0.68 \({}^{\text{c}}\) & 0.26 \({}^{\text{c}}\) & 5.56 \({}^{\text{b}}\) & 72.32 \({}^{\text{a}}\) & 90.01 \({}^{\text{a}}\) & 74.14 \({}^{\text{a}}\) \\ Acetate & 0.20 \({}^{\text{d}}\) & – & 1.77 \({}^{\text{c}}\) & 18.17 \({}^{\text{b}}\) & 32.75 \({}^{\text{a}}\) & 18.69 \({}^{\text{b}}\) \\ Methyl-acetate & – & – & – & 7.10 \({}^{\text{a}}\) & 3.41 \({}^{\text{b}}\) & 6.48 \({}^{\text{a}}\) \\ Propionate & – & – & – & – & – & – \\ Methylpropionate & – & – & – & – & 6.53 \({}^{\text{a}}\) & 0.05 \({}^{\text{b}}\) \\ Butyrate & – & 0.26 \({}^{\text{d}}\) & 0.87 \({}^{\text{d}}\) & 20.95 \({}^{\text{c}}\) & 30.37 \({}^{\text{a}}\) & 23.46 \({}^{\text{b}c}\) \\ Methylbutyrate & – & – & – & 20.62 \({}^{\text{a}}\) & 8.8 \({}^{\text{b}}\) & 18.94 \({}^{\text{a}}\) \\ Pentanoate & – & – & – & 1.13 \({}^{\text{a}}\) & 1.04 \({}^{\text{a}}\) & – \\ Hexanoate & 0.30 \({}^{\text{c}}\) & – & 2.80 \({}^{\text{a}}\) & – & 2.46 \({}^{\text{a}}\) & 1.14 \({}^{\text{b}}\) \\ Octoate & – & – & – & – & 2.67 \({}^{\text{a}}\) & – \\ Decanoate & – & – & – & – & 0.77 \({}^{\text{a}}\) & – \\ Others & 0.18 \({}^{\text{c}}\) & – & 0.12 \({}^{\text{c}}\) & 4.35 \({}^{\text{a}}\) & 1.21 \({}^{\text{b}}\) & 5.38 \({}^{\text{a}}\) \\ \hline Total (Aldehydes) & 58.50 \({}^{\text{a,b}}\) & 69.31 \({}^{\text{a}}\) & 51.12 \({}^{\text{b}}\) & 10.37 \({}^{\text{c}}\) & 4.44 \({}^{\text{d}}\) & 1.52 \({}^{\text{e}}\) \\ Hexanal & 22.50 \({}^{\text{b}}\) & 35.92 \({}^{\text{a}}\) & 17.25 \({}^{\text{b}}\) & 2.03 \({}^{\text{c}}\) & – & – \\
2-Hexenal & 11.16 \({}^{\text{a}}\) & 0.76 \({}^{\text{c}}\) & 10.5 \({}^{\text{b}}\) & – & – & – \\ (\(E\))-2-Hexenal & 25.08 \({}^{\text{a,b}}\) & 31.17 \({}^{\text{a}}\) & 23.13 \({}^{\text{b}}\) & 8.34 \({}^{\text{c}}\) & 4.44 \({}^{\text{d}}\) & 1.52 \({}^{\text{e}}\) \\ Others & 0.06 \({}^{\text{b}}\) & 1.46 \({}^{\text{a}}\) & 0.22 \({}^{\text{b}}\) & – & – & – \\ \hline Total (Alcohols) & 21.12 \({}^{\text{b}}\) & 21.47 \({}^{\text{b}}\) & 39.95 \({}^{\text{a}}\) & 0.27 \({}^{\text{e}}\) & 2.45 \({}^{\text{d}}\) & 6.85 \({}^{\text{c}}\) \\
1-Hexanol & 21.12a & 21.47 \({}^{\text{a}}\) & 12.33 \({}^{\text{b}}\) & – & – & – \\ Others & – & – & 27.62 \({}^{\text{a}}\) & 0.27 \({}^{\text{d}}\) & 2.45 \({}^{\text{c}}\) & 6.85 \({}^{\text{b}}\) \\ \hline \hline \end{tabular}  
\(-\): not detectable. \({}^{\text{i}}\) Statistical analysis was performed by [PERSON]’s multiple range test. Means with different letters (\({}^{\text{a,b,c,d,e}}\)) within a row are significantly different at \(p<0.05\).  
\end{table} 
Table 4: Comparison of the main volatiles compounds in Brazilian and Fenjiao banana fruit at various stages of ripening. The k-means clustering analysis showed that two main group were distinguished for the volatiles production in Brazilian fruit. One group situated in the origin of the coordinate, which including most of the esters anddehydes components. Volatiles in this group were mainly produced at the fruit turning and full ripening stage (Figure 2A). The second group located in the middle part of the coordinate, including _trans_-2-hexenal, hexanal and 1-hexanol etc., which accumulated during both stage of green and turning stage. For the cv. Fenjiao (Figure 2B), the first two components could explain 96.5% of the variability among the samples, i.e., 63.1% (PC1) and 33.4% (PC1). As shown in Figure 2B, Fenjiao banana fruit showed quite different volatiles characters from Brazilian fruit. The volatiles at green and turning stage grouped together, which both situated on the _x_-axis. Aldehydes and alcohols were the predominance of volatiles at the turning and green stage for Fenjiao fruit, which mainly presented the PC1.