Preserving Agricultural Diversity: Comprehensive Characterisation of the Local Reineta de Fontanelas Apple Cultivar

The conservation and characterisation of traditional apple cultivars are essential for safeguarding agrobiodiversity and supporting regional economies. Reineta de Fontanelas, a long-established cultivar from the Saloia region of Sintra, Portugal, remains insufficiently described despite its cultural relevance. This study provides the first integrated characterisation of Reineta de Fontanelas apples collected from six local producers, evaluating biometric traits, physicochemical and nutritional composition, free sugars, organic acids, phenolic compounds, antioxidant capacity, colour, texture, and sensory attributes. The multi-site sampling design enabled the assessment of intra-cultivar qualitative variability across different local environments and traditional low-input practices, which constituted the primary objective. A commercial Reineta sample was included solely as a contextual retail benchmark, acknowledging that differences in origin, orchard management, and storage conditions do not allow for strict cultivar-level comparisons. Reineta de Fontanelas apples consistently exhibited high soluble solids (SS), lower titratable acidity (TA), and enriched levels of key phenolic compounds, together with stronger antioxidant activity. Sensory evaluation indicated a sweeter and more aromatic profile for the local apples. Multivariate analysis revealed a coherent compositional fingerprint and identified the main sources of intra-cultivar variability. Overall, the findings show that Reineta de Fontanelas maintains distinctive nutritional, bioactive, and sensory attributes across local environments, supporting ongoing efforts for its conservation and valorization.