Analysis of volatile markers of olive oils and flavored oils: quality grade evaluation and study of modification during storage

This thesis presents the main results of a Ph.D. project focused on the analysis of volatile compounds in virgin and flavored olive oils, to enhance quality control and monitor their evolution during storage. The research was conducted within the field of food science and technology, with particular focus on industrial applicability. For virgin olive oils (VOOs), the first objective was the development of chemometric models based on volatile profiles acquired by headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS). Partial Least Squares-Discriminant Analysis (PLS-DA) models, calibrated on 355 samples and externally validated with 154 oils, achieved a 75% correct classification rate in agreement with the Panel test, confirming the potential of HS-GC-IMS as a rapid screening tool. An inter-laboratory study further demonstrated that harmonized analytical protocols generate reproducible datasets, enabling the development of transferable models and representing a crucial step toward system implementation. The influence of agronomical practices and ripening degree on the volatile and phenolic composition of the monovarietal cultivar Nostrana di Brisighella was also investigated. Results highlighted significant effects on sensory and nutritional properties, supporting the definition of production practices oriented toward maximizing quality. Subsequently, the shelf-life of these oils was monitored over 12 months under room temperature and daylight exposure conditions. The integrated application of targeted and untargeted chromatographic techniques (SPME-GC–MS, HS-GC-IMS, Flash-GC), combined with sensory analysis, revealed a progressive decline in freshness-related volatile markers and a concomitant increase in oxidation products (e.g., pentanal, hexanal, nonanal), associated with quality downgrading and relevant for defining an appropriate “best before” date. Finally, flavored olive oils were investigated. Through the integration of SPME-GC-MS and HS-GC-IMS, distinctive volatile markers were identified for each flavoring agent, which could be employed as practical tools for quality control and for ensuring reproducibility in industrial-scale production.