Combining analysis of fatty acid composition and δ13C in extra-virgin olive oils as affected by harvest period and cultivar: Possible use in traceability studies

The variability in carbon isotope composition (δ13C) of the main olive oil fatty acids, together with their relative contents, have been measured in 60 monovarietal olive oils, produced from plants grown in the same orchard and harvested at five ripening stages. The fatty acid content was mainly influenced by the cultivar, without significant changes during ripening. On the contrary, the fatty acid δ13C value varied from October to December reflecting physiological responses to environmental variations. ANOVA-Simultaneous Component Analysis (ASCA) was applied to explore the sample variability among factors and interactions. In particular harvest date resulted the main factor affecting our multivariate dataset and OA δ13C resulted the most discriminating parameter related to this factor. On the other side, LA relative content displayed the highest sensitivity to the range of cultivar variability, suggesting that this parameter may be used as a useful tool for studying inter-varietal differences in olive oils. The results find possible application in olive oil authentication and traceability studies.