## 4 Conclusions  
Regarding the evaluation of extractability, the PEF device has proved to be very efficient on olive pastes, and significantly increased the quantity of oil extracted compared to the control. The PEF system, when applied downstream of the crushing stage, did not alter the concentrations of the primary legal quality parameters and did not increase the quantitative variability of total phenols and of the main volatile compounds responsible for freshly cut grass and floral sensory \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Heading**} & \multicolumn{2}{c}{**Nocellara Del Belice**} \\ \cline{2-3}  & **Control** & **PEF-Treated** \\ \hline
**Aldehydes** & & \\ \hline Pentanal & \(51.8\pm 16.6\)\(b\) & \(206.5\pm 13.4\)\(a\) \\ (\(E\))-2-Pentenal & \(40.0\pm 2.8\)\(a\) & \(19.0\pm 2.1\)\(b\) \\ Hexanal & \(468.0\pm 53.7\)\(b\) & \(871.5\pm 24.0\)\(a\) \\ (\(E\))-2-Hexanal & \(5647.0\pm 618.0\)\(a\) & \(5878.3\pm 1258.3\)\(a\) \\ (\(E\),\(E\))-2-4-Hexadienal & \(274.3\pm 23.0\)\(a\) & \(199.3\pm 19.4\)\(b\) \\
24-Hexadienal (i) & \(575.8\pm 54.1\)\(a\) & \(426.3\pm 37.8\)\(b\) \\ \(\Sigma\)Aldehydes & \(7056.8\pm 623.3\)\(a\) & \(7600.8\pm 1259.3\)\(a\) \\ \hline
**Alcohols** & & \\ \hline
1-Pentanol & \(30.8\pm 0.4\)\(b\) & \(71.8\pm 9.5\)\(a\) \\
1-Penten-3-ol & \(223.0\pm 30.4\)\(a\) & \(198.3\pm 11.0\)\(a\) \\ (\(E\))-2-Penten-1-ol & \(110.8\pm 8.1\)\(a\) & \(91.5\pm 9.9\)\(b\) \\ (\(Z\))-2-Penten-1-ol & \(211.8\pm 30.8\)\(a\) & \(127.8\pm 7.4\)\(b\) \\
1-Hexanol & \(1052.8\pm 188.4\)\(a\) & \(792.3\pm 148.1\)\(a\) \\ (\(E\))-2-Hexen-1-ol & \(1000.5\pm 127.3\)\(a\) & \(961.8\pm 117.0\)\(a\) \\ (\(Z\))-2-Hexen-1-ol & \(0.0\pm 0.0\)\(a\) & \(0.0\pm 0.0\)\(a\) \\ (\(E\))-3-Hexen-1-ol & \(106.8\pm 26.5\)\(a\) & \(55.0\pm 8.5\)\(b\) \\ (\(Z\))-3-Hexen-1-ol & \(3735.8\pm 22.3\)\(a\) & \(2558.5\pm 383.3\)\(b\) \\ \(\Sigma\)Alcohols & \(6472.0\pm 305.2\)\(a\) & \(4856.8\pm 437.2\)\(b\) \\ \hline
**Esters** & & \\ \hline Hexyl acetate & \(921.5\pm 106.8\)\(a\) & \(850.3\pm 151.0\)\(a\) \\ (\(Z\))-3-Hexenyl acetate & \(3423.3\pm 308.7\)\(a\) & \(3282.8\pm 264.8\)\(b\) \\ (\(E\))-2-Hexenyl acetate & \(35.8\pm 1.1\)\(a\) & \(17.0\pm 2.1\)\(b\) \\ \(\Sigma\)Esters & \(4380.5\pm 326.6\)\(a\) & \(4150.0\pm 304.8\)\(a\) \\ \hline \hline \end{tabular} Different letters in rows denote significant statistical differences at \(p<0.05\) (Tukey’s test).  
\end{table} 
Table 4: Volatile compounds detected in EVOOs (\(\mathrm{\SIUnitSymbolMicro g}\)/kg). \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Phenolic Compounds**} & \multicolumn{2}{c}{**Nocellara del Belice**} \\ \cline{2-3}  & **Control** & **PEF-Treated** \\ \hline
3,4-DHPEA & \(2.6\pm 2.6\)\(a\) & \(1.5\pm 0.3\)\(a\) \\ \(p\)-HPEA & \(2.1\pm 2.1\)\(a\) & \(1.3\pm 0.3\)\(a\) \\ Vanillic acid & \(0.0\pm 0.0\)\(a\) & \(0.0\pm 0.0\)\(a\) \\
3,4-DHPEA-EDA & \(97.8\pm 9.8\)\(b\) & \(114.8\pm 22.2\)\(a\) \\ \(p\)-HPEA-EDA & \(27.8\pm 0.5\)\(b\) & \(30.1\pm 1.5\)\(a\) \\ (+)-1-acetoxypinoresinol & \(3.1\pm 0.2\)\(a\) & \(3.0\pm 0.3\)\(a\) \\ (+)-pinoresinol & \(5.7\pm 1.7\)\(a\) & \(4.4\pm 0.4\)\(a\) \\
3,4-DHPEA-EA & \(40.0\pm 4.4\)\(a\) & \(41.8\pm 9.5\)\(a\) \\ Ligstroside aglycone & \(4.8\pm 0.7\)\(a\) & \(5.4\pm 0.3\)\(a\) \\ Total phenols & \(184.0\pm 11.4\)\(a\) & \(202.3\pm 9.9\)\(a\) \\ \hline \hline \end{tabular} Different letters in rows denote significant statistical differences at \(p<0.05\) (Tukey’s test).  
\end{table} 
Table 3: Phenolic composition of EVOOs (\(\mathrm{\SIUnitSymbolMicro g}\)/kg). notes. Qualitatively, significant differences were detected in the concentrations of some oleupopein and ligstroside derivatives, and of the sum of alcohols. From a plant engineering perspective, a PEF device used during experimental tests demonstrated easy assembly and implementation inside the mill without substantially modifying the basic layout.