Characterization and differentiation of Calabrian extra virgin olive oil: a multivariate study

This study aimed to characterize and discriminate extra virgin olive oils (EVOOs) obtained from three Olea europea traditional Calabrian cultivars Sinopolese, Roggianella, and Ottobratica, through an integrated chemometric approach. A comprehensive analysis was conducted on their physicochemical parameters (free acidity, peroxide value, fatty acids), antioxidant properties evaluated by 1,1 diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS) tests, oxidative stability, tocopherol content, and detailed phenolic profiles determined by high-performance liquid chromatography with diode array detector (HPLC-DAD) method. Significant differences (p < 0.05) were observed among the cultivars for most variables, particularly in total phenols, alpha-tocopherol, and key phenolic markers. Roggianella showed the highest levels of total phenols and tocopherols, while Ottobratica was richer in phenolic acids and lignans. Sinopolese was distinguished by its unique content of secoiridoids and specific flavonoids. To explore data structure and varietal differentiation, multivariate statistical analyses were applied. Principal Component Analysis (PCA) explained 100% of the total variance with the first two components (PC1 = 70.2 and PC2 = 29.8), effectively separating the cultivars. Hierarchical Cluster Analysis (HCA) confirmed this separation, grouping Roggianella and Ottobratica together, while Sinopolese formed an independent cluster. A Partial Least Squares Discriminant Analysis (PLS-DA) further enhanced cultivar discrimination, identifying key compositional markers through Variable Importance in Projection (VIP) scores. The most relevant discriminants (VIP > 1) included hydroxytyrosol acetate, 1-acetoxypinoresinol, 3,4-DHPEA-EDA. These findings confirm that chemometric tools are effective in distinguishing EVOOs based on their compositional profiles, supporting their application in varietal authentication, quality control, and the valorization of regional olive germplasm.