# The Potential of Apulian Olive Biodiversity: The Case of Oliva Rossa Virgin Olive Oil
## 3 Results
### VOOs Characteristics
Less ripe drupes (S2) gave oils with less total volatile compounds, whose profile was dominated by (_E_)-2-hexenal, 3-ethyl-1,5-ocadiene, C5 compounds (1-penten-3-one, (_Z_)-2-penten-1-ol, 1-penten-3-ol) and (_Z_)-3-hexen-1-ol. In particular, (_Z_)-3-hexen-1-ol, which was significantly higher at S2 with respect to the other stages, was already reported as one of the indicators of the early stage of ripeness [4]. At the technological optimum (i.e., S3), the highest amount of total volatile compounds was observed. In detail, the oils were characterized by the significantly higher content of pentanal, 3-ethyl-1,5-ocadiene, 1-penten-3-one, (_E_)-2-hexenal and (_Z_)-2-penten-1-ol. It is reported that the maximum content of (_E_)-2-hexenal is reached when the drupes' pigmentation changes from green to purple and then decrease with ripening [4,5]. However, this trend could be even cultivar dependent. At S3, a noticeable content of acetic acid was found, too. Acetic acid could originate from the fermentation process and might be linked to some organoleptic defects such as wine-vinegarty [55]. However, the detection of such defects involves many other volatile compounds [55]. At S4, a decrease in the total volatile compounds was observed with respect to S3. The oils were characterized by an increase in the acetate esters, which was associated with a decrease in the acetic acid content. A significantly higher content of \begin{table}
\begin{tabular}{l c c c} \hline
**Compound** & **S2** & **S3** & **S4** \\ \hline Methyl acetate & 2.28 \(\pm\) 0.58 b  & 1.82 \(\pm\) 0.89 b  & 5.25 \(\pm\) 0.29 a  \\ Ethyl acetate & 0.40 \(\pm\) 0.05 b  & 1.25 \(\pm\) 0.49 a  & 1.47 \(\pm\) 0.03 a  \\
2-Methyl butanal & 1.83 \(\pm\) 0.43 b  & 1.65 \(\pm\) 0.22 b  & 5.18 \(\pm\) 0.54 a  \\
3-Methyl butanal & 2.53 \(\pm\) 0.57 b  & 2.07 \(\pm\) 0.18 b  & 7.84 \(\pm\) 0.44 a  \\
3-Pentanone & 1.25 \(\pm\) 0.29 a  & 1.64 \(\pm\) 0.29 a  & 1.69 \(\pm\) 0.20 a  \\ Pentanal & 1.07 \(\pm\) 0.12 c  & 13.78 \(\pm\) 1.73 a  & 4.00 \(\pm\) 0.79 b  \\
3-Ethyl-1,5-ocadiene & 15.81 \(\pm\) 3.00 b  & 37.05 \(\pm\) 9.52 a  & 16.60 \(\pm\) 2.21 b  \\
1-Penten-3-one & 6.23 \(\pm\) 0.67 c  & 16.34 \(\pm\) 0.84 a  & 8.42 \(\pm\) 0.78 b  \\ Hexanal & 2.72 \(\pm\) 0.44 b  & 4.81 \(\pm\) 0.42 a  & 4.29 \(\pm\) 0.85 a  \\ (_E_)-2-Pentenal & 0.82 \(\pm\) 0.19 a  & 1.32 \(\pm\) 0.24 a  & 0.65 \(\pm\) 0.32 b  \\
1-Penten-3-ol & 2.95 \(\pm\) 0.34 c  & 4.85 \(\pm\) 0.42 b  & 10.52 \(\pm\) 0.15 a  \\ (_E_)-2-Hexenal & 70.37 \(\pm\) 9.18 b  & 111.88 \(\pm\) 14.16 a  & 86.69 \(\pm\) 7.13 a  \\ (_Z_)-3-Hexen-1-yl acetate & 0.84 \(\pm\) 0.20 b  & 0.10 \(\pm\) 0.03 b  & 11.42 \(\pm\) 1.11 a  \\ (_Z_)-2-Penten-1-ol & 4.51 \(\pm\) 0.46 c  & 18.16 \(\pm\) 1.30 a  & 9.94 \(\pm\) 1.07 b  \\ Acetic acid & 3.69 \(\pm\) 0.36 b  & 8.48 \(\pm\) 1.19 a  & 3.59 \(\pm\) 1.44 b  \\ Hexanal-1-ol & 1.49 \(\pm\) 0.92 a  & 1.10 \(\pm\) 0.30 a  & 1.99 \(\pm\) 0.69 a  \\ (_Z_)-3-Hexen-1-ol & 4.47 \(\pm\) 0.31 a  & 1.71 \(\pm\) 0.09 c  & 3.41 \(\pm\) 0.44 b  \\ \hline Total & 123.25 \(\pm\) 9.81 b  & 228.00 \(\pm\) 17.31 a  & 182.95 \(\pm\) 7.97 a  \\ \hline \end{tabular}
\end{table}   
* OE, 1-ocanol equivalents. Different letters for each parameter indicate significant differences according to one-way ANOVA followed by [PERSON]’s LSD post-hoc test (\(\alpha\) = 0.05). S2-S4: three subsequent samplings. \begin{table}
\begin{tabular}{l c c} \hline
**Compound** & **S2** & **S3** & **S4** \\ \hline Methyl acetate & 2.28 \(\pm\) 0.58 b  & 1.82 \(\pm\) 0.89 b  &2-methyl butanal, 3-methyl butanal and 1-penten-3-ol was reported, too. The correlation among the volatile compounds and sensory features of the VOOs is well known [4; 5; 56]. Based on this, and considering the data reported in Table 5, it could be supposed that Oliva Rossa oils have notes of fruity, green, cut-leaves and almond, which is in accordance with the few data available in the literature [24].