## 3 Results
### Volatile Aroma Compound Profiles
#### 3.1.3 Aldehydes  
Among unsaturated aldehydes formed in the so-called LOX pathway, Buza, followed by Rosinjola and Oblica EVOOs, contained the highest concentrations of (_E_)- and (_Z_)-3-hexenal, respectively (Table 1). The same monovarietal EVOOs, with sporadic exceptions, were also distinguished by high levels of pentenals, hexadienals, and (_E_)-2-ocneal. Oblica EVOO had high concentration of decadienals. Leccino was clearly distinguished from the other monovarietal EVOOs by the highest level of the major EVOO volatile, (_E_)-2-hexenal, as well as that of (_E_,_E_)-2,4-heptdiagnal. Leccino EVOO had the lowest concentration of (_Z_)-3-hexenal, although not statistically different from that found in I. bjelica and Lastovka EVOOs. Lastovka EVOO was characterized by rather low levels of particular LOX-derived hexenals, as well as pentenals, octanal, and hexadienals. Istarska bjelica contained low concentrations of (_Z_)-3-hexenal and decadienals. Among saturated aldehydes originating from the processes other than LOX, 3-methylbutanal turned out to be an exclusive marker of I. bjelica, while abundance in 2-methyl-2-pentenal was observed in Rosinjola EVOO (Table 1). Higher levels of hexanal clearly discriminated Dalmatian (Oblica and Lastovka) from Istrian monovarietal EVOOs. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Compound** & **ID** & **LRI** & \multicolumn{6}{c}{**Variety**} \\ \cline{5-10}  & & & **Buza** & **L. bijelica** & **Rosinjola** & **Oblica** & **Lastovka** & **Leccino** \\ \hline _Influcarbons_ & & & & & & & & \\ propane & MS & \(\sim\)700 & 6.64 \({}^{\rm hc}\) & 14.91 \({}^{\rm a}\) & 1.12 \({}^{\rm c}\) & 11.49 \({}^{\rm a}\) & 12.51 \({}^{\rm a}\) & 5.43 \({}^{\rm c}\) \\ (Z)-2-pentene & MS & \(\sim\)700 & 61.19 \({}^{\rm b}\) & 80.27 \({}^{\rm a}\) & 60.31 \({}^{\rm b}\) & 33.98 \({}^{\rm c}\) & 43.63 \({}^{\rm c}\) & 83.09 \({}^{\rm a}\) \\
1,4-pentadiene (mg/kg) & LRLMS & \(\sim\)700 & 0.17 \({}^{\rm a}\) & 0.16 \({}^{\rm a}\) & 0.15 \({}^{\rm a}\) & 0.10 \({}^{\rm c}\) & 0.09 \({}^{\rm c}\) & 0.12 \({}^{\rm b}\) \\
1,3-pentadiene & LRLMS & \(\sim\)700 & 81.73 \({}^{\rm a}\) & 75.36 \({}^{\rm b}\) & 71.98 \({}^{\rm b}\) & 53.80 \({}^{\rm c}\) & 48.98 \({}^{\rm c}\) & 62.92 \({}^{\rm b}\) \\
1-heptene & LRLMS & 731 & 5.42 & 16.64 & 3.25 & 9.76 & 5.72 & 6.13 \\
3.5-dimethyl/heptane & MS & 753 & 1.61 & 3.59 & 3.63 & 2.38 & 0.33 & 2.86 \\ propanal & LRLMS & 778 & 7.00 & 5.23 & 7.36 & 5.10 & 5.68 & 7.04 \\ octane & SLLRMS & 800 & 31.03 & 35.33 & 27.29 & 30.78 & 40.92 & 27.11 \\
2,6-dimethyl-3-heptene & MS & 821 & 0.20 \({}^{\rm b}\) & 0.58 \({}^{\rm b}\) & 6.17 \({}^{\rm a}\) & 0.00 \({}^{\rm b}\) & 0.00 \({}^{\rm b}\) & 0.19 \({}^{\rm b}\) \\ (\(E\))-2-octene & LRLMS & 822 & 3.50 & 4.60 & 3.81 & 3.36 & 5.62 & 3.60 \\ branched-chain alkene I (n.i.) & MS & 953 & 94.32 \({}^{\rm a}\) & 63.73 \({}^{\rm a}\) & 85.98 \({}^{\rm a}\) & 47.29 \({}^{\rm a}\) & 38.96 \({}^{\rm a}\) & 74.97 \({}^{\rm b}\) \\ branched-chain alkene II (n.i.) & MS & 960 & 84.13 \({}^{\rm a}\) & 56.70 \({}^{\rm c}\) & 71.63 \({}^{\rm a}\) & 41.67 \({}^{\rm a}\) & 35.22 \({}^{\rm a}\) & 65.24 \({}^{\rm b}\) \\ decane & SLLRMS & 997 & 31.53 \({}^{\rm a}\) & 19.98 \({}^{\rm b}\) & 39.92 \({}^{\rm a}\) & 9.49 \({}^{\rm c}\) & 7.39 \({}^{\rm c}\) & 14.67 \({}^{\rm c}\) \\
3-ethyl-1,5-octadiene I (mg/kg) & LRLMS & 1006 & 0.36 \({}^{\rm a}\) & 0.26 \({}^{\rm c}\) & 0.34 \({}^{\rm a}\) & 0.18 \({}^{\rm a}\) & 0.15 \({}^{\rm a}\) & 0.31 \({}^{\rm b}\) \\
3-ethyl-1,5-octadiene II (mg/kg) & LRLMS & 1020 & 0.40 \({}^{\rm a}\) & 0.25 \({}^{\rm c}\) & 0.35 \({}^{\rm a}\) & 0.20 \({}^{\rm d}\) & 0.16 \({}^{\rm d}\) & 0.31 \({}^{\rm b}\) \\
3-ethyl-1,5-octadiene III & LRLMS & 1033 & 2.99 & 12.91 & 3.19 & 1.24 & 0.79 & 2.60 \\ branched-chain alkene II (n.i.) & MS & 1067 & 0.37 & 10.08 \({}^{\rm a}\) & 0.45 & 0.06 & 0.01 & 0.48 \\
3,7-decadiene I (n.f.)