## 2 Results and Discussion
### Chemical Changes during the Storage Experiment
Although (\(E\))-2-hexenal concentration was reduced in a range of 1.16-3.33 mg/kg (Table 2), this compound with pleasant sensory descriptor showed an OAV higher than 1 during the entire storage time in all samples (OAV \(>\) 2.84 in all cases). Other compounds showing high correlation coefficients (\(>\)0.70) with median of the fruity attribute in some particular oils were (\(Z\))-3-hexen-1-ol (R = 0.93 and 0.70 in VOO1 and VOO4, respectively) and (\(E\))-2-hexen-1-ol (R = 0.96 in VOO1). The concentration of these two compounds is highly influenced by the stage of ripeness [1]. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{1}{c}{**VOO1**} & \multicolumn{2}{c}{**VOO2**} \\
**Compound** & **RSD\%** & **Compound** & **RSD\%** \\ \hline Octane a & 120.82 & Octane & 119.81 \\ Butan-2-ol & 50.00 & Butanal & 58.59 \\
2-methylpropan-1-ol & 93.90 & 2-methylpropan-1-ol & 75.00 \\ Butan-1-ol & 90.08 & Butan-1-ol & 69.05 \\ (\(E\))-2-hexenal & 82.03 & Heptanal a & 107.53 \\ Octan-3-one & 70.06 & Octan-3-one & 92.07 \\ Pentanol & 78.22 & Octan-2-one & 68.64 \\ Octan-2-one & 74.39 & Octanal a & 56.58 \\ Octanal a & 128.77 & 1-octen-3-one a & 64.17 \\
1-octen-3-one & 59.92 & (\(E\))-2-heptenal a & 99.97 \\ (\(E\))-2-heptenal a & 71.08 & 6-methyl-5-hepten-2-one & 64.13 \\
6-methyl-5-hepten-2-one & 61.66 & Nonanal a & 87.46 \\ (\(E\))-3-hexen-1-ol & 107.40 & Butanoic acid & 51.36 \\ (\(Z\))-3-hexen-1-ol & 59.21 & (\(E\))-2-decenal a & 104.44 \\
1-octen-3-ol & 72.03 & Hexanoic acid a & 50.98 \\ (\(E\))-2-hexen-1-ol & 79.88 & Heptanoic acid & 63.61 \\ (\(Z\))-2-hexen-1-ol & 76.50 & Nonanoic acid a & 78.26 \\ Heptanoic acid a & 56.85 & & \\ Octanoic acid a & 59.30 & & \\ Nonanoic acid a & 94.12 & & \\ \hline \multicolumn{1}{c}{**VOO3**} & \multicolumn{2}{c}{**VOO4**} \\
**Compound** & **RSD\%** & **Compound** & **RSD\%** \\ \hline Octane a & 128.80 & Octane a & 106.09 \\ Butanal & 56.41 & Methyl acetate & 50.03 \\ Butan-2-ol & 64.18 & Butan-2-ol & 80.69 \\
2-methylpropan-1-ol & 71.54 & 2-methylpropan-1-ol a & 64.37 \\ Butan-1-ol & 118.65 & (\(E\))-2-pentenal a & 62.07 \\ Heptanal a & 100.26 & Heptanal a & 94.48 \\
2-methylbutan-1-ol a & 99.86 & (\(E\))-2-hexenal & 53.76 \\ Octan-2-one & 77.44 & Octan-3-one a & 79.59 \\ (\(E\))-2-heptenal a & 95.01 & Pentanol a & 53.96 \\
6-methyl-5-hepten-2-one & 97.30 & (\(E\))-2-heptenal a & 95.28 \\ (\(E\))-3-hexen-1-ol & 58.40 & 6-methyl-5-hepten-2-one & 80.14 \\
1-octen-3-ol & 74.51 & Nonanal a & 66.11 \\ (\(Z\))-2-hexen-1-ol & 63.51 & Heptanoic acid a & 78.27 \\ Hexanoic acid & 88.83 & Octanoic acid a & 49.46 \\ Heptanoic acid & 87.90 & Nonanoic acid a & 80.15 \\ Octanoic acid & 76.55 & & \\ Nonanoic acid & 105.60 & & \\ \hline \hline \end{tabular}  
* Compounds that underwent an increase of their concentrations during the storage.  
\end{table} 
Table 3: Selected volatile compounds that showed statistically significant changes (\(p\)-value \(<\) 0.05) and RSD% higher than 50% during the storage at moderate conditions. The OAV values of hexanal was also highly correlated (>0.70) with medians of the fruity attribute, although only in two oils. Thus, the correlation coefficients were 0.91 and 0.76 for VOO1 and VOO3, respectively, while a negative value (-0.66) was obtained for VOO2 and VOO4. Hexanal was not selected by ANOVA when comparing its concentration in the initial and last months of storage (Table 2) and it did not show a change in its concentration with a RSD% > 50% (Table 3). However, the study of its concentration and OAV during the storage under moderate conditions may provide useful information about the oxidation state of the samples since this compound is also produced during oxidation and it has an evident implication in virgin olive oil rancidity [3; 40]. Figure 4 shows the OAV of hexanal and the medians of the fruity attribute and the defect represented on a double-y graph with respect to the storage time. Two kinds of trends of its OAV during the storage was observed.