From global to PDO: sesquiterpene fingerprinting for comprehensive geographical authentication of virgin olive oils

The verification of the geographical origin of extra virgin (EVOO) and virgin olive oil (VOO) is essential to protect consumers from misleading information. Currently, this verification relies solely on documentary reviews, as no official analytical methods have been approved. Developing reliable tools for geographical authentication requires identifying robust markers and analytical techniques. To serve as effective geographical markers, these indicators must primarily reflect climatic and agronomic factors specific to a region, with minimal influence from other variables. Sesquiterpene hydrocarbons (SHs) have proven to be excellent geographical markers for VOO due to their strong association with olive tree cultivars and growing regions, combined with their stability against post-harvest processing and storage conditions. Furthermore, SHs are semi-volatile metabolites that can be analyzed through headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). This method is simple, affordable, and automatable.

Here, we present the results of an SH fingerprinting approach for authenticating the geographical origin of VOO at various levels, including EU-wide, single-country, and Protected Designation of Origin (PDO) labels. Using Partial Least Squares-Discriminant Analysis (PLS-DA), classification models were built with large datasets ( >300 samples) encompassing multiple harvests, cultivars, and origins. External validation of these models demonstrated exceptionally high classification accuracy, highlighting the effectiveness of this approach.

Compared to other established geographical markers, SH fingerprinting consistently exhibited superior classification performance. These results underscore its potential as a reliable and practical screening tool for verifying the geographical origin of VOO.