Altitude-Driven Variations in the Lipid Profile of Extra Virgin Olive Oil: A Chemometric Approach for Geographical Authentication

The influence of altitude on the chemical composition of extra virgin olive oil (EVOO) remains incompletely characterized despite its critical importance for geographical authentication and Protected Designation of Origin (PDO) certification. This study investigated the altitude-driven effects on the fatty acid and triacylglycerol (TAG) profiles of 25 EVOO samples collected across 21 distinct altitudes ranging from 450 to 1045 m above sea level in a mountainous olive-growing region. Chromatographic analyses (GC-FID and HPLC-RID) quantified 37 lipid parameters including 13 individual fatty acids and 24 TAG species. Correlation analysis revealed that higher altitudes were significantly associated with decreased saturated fatty acid (SFA) content (r = −0.417, p = 0.038), increased monounsaturated fatty acid (MUFA) content (r = 0.401, p = 0.047), and an elevated MUFA/polyunsaturated (PUFA) ratio (from 16.3 at 450 m to 22.7 at 1045 m). Palmitoleic acid (C16:1; r = −0.695, p < 0.001) and oleic acid (C18:1; r = 0.434, p = 0.030) exhibited the strongest individual correlations with altitude. Among the TAGs, OOO+PoPP (1,2,3-trioleoylglycerol and 1-palmitoleoyl-2,3-dipalmitoylglycerol; co-eluting fraction) increased with altitude (r = 0.469, p = 0.018), whereas polyunsaturated TAG species decreased significantly. Linear discriminant analysis (LDA) achieved a classification accuracy of 96.0% (24/25 samples correctly classified), with the first two discriminant functions explaining 91.1% of the between-class variance. These findings demonstrate that altitude exerts a systematic and quantifiable effect on EVOO lipid composition, providing an analytical framework for geographical authentication, PDO verification, and quality differentiation of mountain-origin olive oils.