# The Potential of Apulian Olive Biodiversity: The Case of Oliva Rossa Virgin Olive Oil
## 3 Results
### VOOs Characteristics
In the 2017/2018 crop season, the mean temperatures registered during fruits ripening were actually lower than those registered in the 2019/2020 season (Figure S1) and could justify the differences observed in terms of fatty acids composition. From a technological point of view, it is a fact that the different composition in fatty acids could in turn influence the oxidative stability of the product. In particular, values of O/L equals or higher than 7 have been suggested as an indication of good stability [45]. From Table 1, it could be observed that the ratio was different between the years and, in 2017/2018, it was always higher than 7. The results of the basic chemical analyses of the VOOs are reported in Table 2.  
FFA is commonly the benchmark parameter for the vertical differentiation of olive oils into a specific product class (extra, virgin and lampante) [9]. The mean oil acidity ranged from 0.61% to 0.34%, being on average higher in the harvest season 2017/2018. The observed values could be considered quite high for freshly extracted oils. During maturation, a significant decrease in FFA was observed in 2019/2020. This decreasing \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Harvest Season** & **Pi \({}^{*}\)** & **Sampling** & **FFA (g 100 g\({}^{-1}\))** & **PV (mEq O\({}_{2}\) kg\({}^{-1}\))** & **K\({}_{232}\)** & **K\({}_{270}\)** \\ \hline  & 1.92 & S2 & 0.61 \(\pm\) 0.06 \({}^{\text{a}}\) & 7.49 \(\pm\) 0.28 \({}^{\text{c}}\) & 1.94 \(\pm\) 0.08 \({}^{\text{c}}\) & 0.21 \(\pm\) 0.03 \({}^{\text{a}}\)b \\
2017/2018 & 1.93 & S3 & 0.58 \(\pm\) 0.07 \({}^{\text{a}}\) & 7.15 \(\pm\) 0.23 \({}^{\text{c}}\) & 1.80 \(\pm\) 0.12 \({}^{\text{d}}\) & 0.20 \(\pm\) 0.06 \({}^{\text{a}}\)b \\  & 3.12 & S4 & 0.58 \(\pm\) 0.06 \({}^{\text{a}}\) & 6.05 \(\pm\) 0.28 \({}^{\text{d}}\) & 1.76 \(\pm\) 0.02 \({}^{\text{d}}\) & 0.23 \(\pm\) 0.04 \({}^{\text{a}}\) \\ \hline  & 2.43 & S2 & 0.52 \(\pm\) 0.04 \({}^{\text{a,b}}\) & 8.92 \(\pm\) 0.22 \({}^{\text{b}}\) & 2.34 \(\pm\) 0.05 \({}^{\text{b}}\) & 0.17 \(\pm\) 0.02 \({}^{\text{a,b}}\) \\
2019/2020 & 3.57 & S3 & 0.43 \(\pm\) 0.06 \({}^{\text{b,c}}\) & 11.02 \(\pm\) 0.48 \({}^{\text{a}}\) & 2.46 \(\pm\) 0.10 \({}^{\text{a,b}}\) & 0.18 \(\pm\) 0.03 \({}^{\text{a,b}}\) \\  & 3.83 & S4 & 0.34 \(\pm\) 0.07 \({}^{\text{c}}\) & 11.03 \(\pm\) 0.67 \({}^{\text{a}}\) & 2.52 \(\pm\) 0.04 \({}^{\text{a}}\) & 0.16 \(\pm\) 0.03 \({}^{\text{b}}\) \\ \hline \end{tabular}  
* \({}^{\text{a}}\) Pi (mean, \(n=3\)) of the drupes at the moment of oil extraction; FFA, free fatty acids; PV, peroxide value; K\({}_{232}\) and K\({}_{270}\), specific absorption at 232 and 270 nm, respectively. Different letters for each parameter indicate significant differences according to two-way ANOVA followed by [PERSON]’s LSD post-hoc test (\(\alpha=0.05\)). S2–S4: three subsequent samplings.  
\end{table} 
Table 2: Basic quality parameters of the Oliva Rossa VOOs extracted during fruit ripening in two different harvest seasons (mean \(\pm\) SD, \(n=3\)). trend was also reported by other authors [16]. Moving to the oxidation assessment, PV and K\({}_{232}\) are generally considered markers of primary oxidation, while K\({}_{270}\) is a marker of secondary oxidation products. Differences were highlighted considering both the harvest season and the sampling time. A specular trend was observed between the years. The oils extracted in 2019/2020 were affected by a higher extent of primary oxidation (PV and K\({}_{232}\)) but, on the average, by a less pronounced secondary oxidation (K\({}_{270}\)). This might be linked to the significantly higher amount of PUFA in oils from 2019/2020 and to the significantly lower value of O/L (Table 1), indices of a higher susceptibility to oxidation. On the whole, from Table 2, it could be stated that the Oliva Rossa VOOs still were classified as extra virgin olive oil (based on the reported parameters) till S3, which, in turn, corresponded to the maximum oil content (Figure 2).