Ripening Crossroads: How Cultivar and Harvest Timing Shape the Extremadura Virgin Olive Oils

Virgin olive oil (VOO) quality is strongly influenced by olive cultivar and fruit maturity stage, yet their combined effects remain insufficiently characterized in many traditional olive-growing regions. This study evaluated the physicochemical parameters, phenolic compounds content, antioxidant activity, fatty acid profile, volatile compounds, and sensory attributes of VOOs obtained from five autochthonous cultivars of Extremadura (Spain)—‘Corniche’, ‘Manzanilla Cacereña’, ‘Morisca’, ‘Pico Limón’, and ‘Verdial de Badajoz’—harvested at three ripening stages (Green, Verging-on-ripe, and Ripe). Early harvest oils exhibited significantly higher total phenolic content (up to 478 mg/kg expressed by caffeic acid equivalent, CAE), oxidative stability (up to 188 h), intense green-fruity notes dominated by (E)-2-hexenal and (Z)-3-hexenal, and stronger bitterness and pungency. As ripening progressed, phenolic compounds and LOX-derived C6 volatiles markedly decreased, while oil yield, linoleic acid, saturated aldehydes, and oxidation markers increased in most cultivars. Cultivar-specific responses were evident: ‘Corniche’ and ‘Manzanilla Cacereña’ maintained higher oleic acid and stability, whereas ‘Morisca’ and ‘Pico Limón’ were more prone to phenolic compound loss and sensory deterioration at full ripeness. Multivariate analysis confirmed strong genotype × maturity interactions shaping oil quality. Optimal harvest timing must therefore be tailored to each cultivar to maximize phenolic content, oxidative stability, and sensory excellence while balancing industrial yield.