Olive leaves are a rich source of polyphenols with healthful properties and represent one of the most abundant waste products of olive oil production. The aims of this study were to explore the phenolic composition of olive leaves from the three main Tuscan cultivars (Leccino, Moraiolo and Frantoio) collected in Siena and Grosseto provinces and to investigate the possible use of these compounds as varietal and geographic origin markers. Discriminant factorial analysis (DFA) was used for distinguishing between different cultivars and locations. Apigenin and caffeoyl-secologanoside showed significant differences between cultivars. DFA showed that ligstroside, apigenin and luteolin have the most influence in determining the differences between sites, whereas total polyphenols, olacein and hydroxytyrosol acetate allowed for separation between leaves from the same province. The results of the present study indicate that concentrations of phenolic compounds, measured through high-resolution mass spectrometry, can be used as a marker for both the cultivar and of geographical origin of olive leaves, and possibly of olive-related products, as well as across small geographic scales (less than 50 km distance between sites).

The oxidative stability of extra virgin olive oil (EVOO) is a key quality parameter influenced by its composition and antioxidant content. The determination of EVOO oxidative stability under stress conditions will help to address its nutritional properties and shelf life. This study investigates the oxidative behaviour of Tuscan EVOOs by combining Electron Paramagnetic Resonance (EPR), detailed compositional profiling and multivariate analysis. Significant variability in both radical generation and antioxidant capacity was observed among samples. Multivariate analyses (PCA, PLS), integrating chemical data, revealed that tocopherols, phenolic compounds, and fatty acid profiles, particularly MUFA/PUFA ratios, strongly influence oxidative resistance. In particular, given that oil samples have all an oleic acid content higher than 72 %, the polyphenol/tocopherol ratio is the main responsible of the oxidative stability of EVOOs. This study highlights the interplay between composition and oxidative stability with the aim, once a greater number of dataset will be available, to build a predictive model to define EVOOs oxidative stability.

A HPLC-HRMS method was developed and validated to analyze the polyvinylimidazole/polyvinylpyrrolidone (PVI/PVP) monomers (N-vinylimidazole, N-vinyl-2-pyrrolidone, imidazole, and 2-pyrrolidone) in wines. The use of a C30 column and HRMS allowed to obtain high selectivity, excluding several interferents. The lower limit of quantification was 10 ng/mL for the targeted molecules and the method was linear from 10 to 1000 ng/mL. Matrix effect (ME) was detected for all compounds, except for N-vinylimidazole and a correction function to overcame ME was suggested with the use of a calibration curve in hydroalcoholic solution. Migration tests demonstrated that imidazole reveals the oenological use of PVI-based products, whereas 2-pyrrolidone represents a very questionable marker for PVPP fining agents since all analyzed wines showed levels of this compound higher than the limit defined by OIV. Further investigations are necessary to test commercial products using both model and real wines in order to find new markers of PVPP treatment.