Olive oil quality is shaped by genetic factors, environmental conditions, and the fruit’s maturation stage. This study evaluated the chemical composition and quality of virgin olive oils obtained from two principal Tunisian olive varieties: Chemlali Sfax from central Tunisia and Chetoui from the north. The results indicate that olive oil characteristics are impacted by both cultivar and fruit maturity stages. In both varieties, total oil content and fatty acid composition were assessed at different ripening stages, with oil content reaching up to 30% of fresh weight at full ripeness. During maturation, the free acidity increased from 0.2% to 0.4%, and linoleic acid content rose by approximately 15%, especially in both varieties’ later ripening stages. The fatty acid profile revealed higher oleic acid levels in Chetoui (up to 68%) compared to Chemlali Sfax (60%). Antioxidant content, such as carotens, decreased from 6.79 to 2.34 for the Chetoui variety and 7.83 to 5.53. The Chemlali Sfax variety and its related parameters, such as phenols and pigments (chlorophyll), tended to decline with fruit ripening, resulting in distinct compositional profiles that can serve as varietal and maturity indicators.
These findings underline the importance of cultivar selection and harvest timing in optimizing olive oil quality and resilience to changing environmental conditions.