Changes in the volatile profile, fruity flavor, and rancidity in virgin olive oils during storage by targeted and untargeted analytical approaches

The changes in monovarietal extra virgin olive oils (EVOOs), produced with olives grown under different agronomic conditions, were investigated by targeted and untargeted analytical approaches. Specifically, volatile molecules were monitored in oils just produced and stored for 6 and 12 months with two different packaging solutions. The targeted SPME-GC–MS method showed an increase in volatile markers of lipid oxidation. Moreover, more rapid analytical approaches, namely targeted HS-GC–IMS and untargeted FGC, were used to investigate volatile organic compounds (VOCs). These chromatographic methods, respectively, returned heatmaps and fingerprint profiles that were elaborated on by multivariate analysis. Exploratory principal component analysis performed on the data from VOCs allowed the clustering of samples based on the storage time. The quality of samples was also determined by a panel test. Furthermore, this study employed previously built models using partial least squares discriminant analysis to confirm the sensory classification of the stored samples. Based on these predictive models, all samples were confirmed as EVOO, except for one categorized as virgin (rancid according to the panel test). This classification was further supported by the SPME-GC–MS analysis, which revealed higher concentrations of lipid oxidation markers in this specific sample, in particular the (E)-2-heptenal reached a concentration twenty times higher than its odor threshold. In addition, five oils were inconsistently classified by the models and considered at risk of downgrading the commercial category after 12 months of storage.