## 3 Results and Discussion
### Fatty Acid Profile of the Two Monocultivar Olive Oils  
Fatty acid profile plays an important role in the quality and characterization of an olive oil as its composition reflects the nutritional properties of an olive oil [27]. Several researchers have reported that among other major components, fatty acids composition seems to represent a possible tool for varied characterization and authentication [28; 29; 30; 31; 32; 33]. Table 2 shows the mean fatty acid composition of the analyzed monovarietal olive oils. As it is shown, all fatty acids identified were found in the normal range expected for the extra virgin olive oil category for both monocultivars. With respect to the mono-unsaturated oleic acid (C18:1), olive oils of cv. Koroneiki presented a higher concentration with a mean value of 75.07% compared to cv. Lianolia Kerkyras (69.55%). Moreover, the saturated stearic acid (C18:0) concentration was higher for cv. Koroneiki with a mean value of 2.51% compared to the concentration of 2.04% for cv. Lianolia Kerkyras. On the other hand, olive oils of cv. Lianolia Kerkyras presented a clearly higher concentration of the poly-unsaturated linoleic acid (C18:2) with a mean value of 10.40% compared to the Koroneiki olive oils (6.43%) as well as a higher concentration in palmitic acid (14.46%). Regarding the comparison of the contents of the different lipids in the two varieties, the different flesh to stone ratio is characteristic of the olives themselves. The flesh to stone ratio is 3-4 to 1 in cv. Lianolia Kerkyras and 5 to 1 in cv. Koroneiki, and the stone is relatively large in the latter, according to the catalogue of \"Apulian and Greek Olive Varieties\". This anatomical characteristic combined with the fact that the olive seeds are richer in linoleic acid and beta-sitosterol than the olive pulp [34] could explain the higher content of these components in cv. Lianolia Kerkyras. Moreover, the discrimination of the two varieties can also be aided and explained by the 18:1/18:2 ratio which indicates that the ratio in cv. Koroneiki is double that of cv. Lianolia Kerkyras. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multicolumn{2}{c}{**cv. Koroneiki (N = 44)**} & \multicolumn{2}{c}{**cv. Lianolia Kerkyras (N = 60)**} & \multicolumn{2}{c}{**EEC Limit for Extra Virgin**} \\  & **Mean \(\pm\) SD** & **Min-Max** & **Mean \(\pm\) SD** & **Min-Max** & **Olive Oil (EVOO) Category** \\ \hline Free acidity (\%) & 0.24 \(\pm\) 0.10 & 0.13–0.55 & 0.27 \(\pm\) 0.12 & 0.12–0.75 & \(\leq\)0.80 \\ Peroxide value & 6.64 \(\pm\) 1.26 & 3.81–9.66 & 5.21 \(\pm\) 1.12 & 3.41–8.64 & \(\leq\)20 \\ (meqO\({}_{2}\)/kg) & 1.56 \(\pm\) 0.14 & 1.39–2.04 & 1.61 \(\pm\) 0.15 & 1.25–1.95 & \(\leq\)2.50 \\ K\({}_{268}\) & 0.14 \(\pm\) 0.01 & 0.11–0.19 & 0.14 \(\pm\) 0.02 & 0.11–0.21 & \(\leq\)0.22 \\ \hline \hline \end{tabular} Values are expressed as means \(\pm\) standard deviation (SD). \(N=104\).  
\end{table} 
Table 1: Quality indices for the examined Koroneiki and Lianolia Kerkyras olive oils from the coastline region of Western Greece. Variability in fatty acid composition between the two monocultivar olive oil samples led to the performance of an analysis of variance (ANOVA) in order to assess their differences. Table 2 shows substantial statistical differences between Lianolia Kerkyras and Koroneiki samples in almost all the analyzed fatty acids (\(p<0.05\)). The analysis of variance applied to the 13 GC analyzed variables allowed the variables with the highest discriminant power to be determined. The more discriminant variables are C18:2 (F = 343.19), C18:1 (F = 264.70), C18:0 (F = 149.88), C16:1 (F = 125.54), C16:0 (F = 71.21), C20:0 (F = 65.71), and C18:3 (F = 22.28). The effect of cultivar in the fatty acid profile of the two monocultivar olive oils originating from the coastline region of north-western Greece is depicted from the results of this work proving the usefulness of fatty acid composition for this varietal discrimination.