Influence of accession, maturity stage, and harvest on the bioactive compounds and antioxidant capacity of Sicana odorifera fruits

Sicana odorifera (Vell.) Naudin, known in Paraguay as “kurugua”, is a native edible fruit species with potential as a source of bioactive compounds. However, the influence of biological and environmental factors on its composition and antioxidant properties remains poorly studied. The objective was to evaluate the effect of accession, maturity stage, and harvest year on the total phenolic content (TPC), total carotenoid content, and antioxidant capacity of S. odorifera pulp. Fruits from the black (KN) and red (KR) accessions were analyzed at both mature and immature stages, representing the 2025 and 2026 harvests. TPC was determined using the Folin-Ciocalteu assay, and total carotenoids were measured via spectrophotometry. Antioxidant capacity was assessed using three complementary assays: ABTS, DPPH, and ORAC-FL. Additionally, a principal component analysis (PCA) was performed to explore the relationships among the variables studied. TPC values ​​ranged from 174 to 228 mg GAE/100 g, while carotenoid content varied between 147 and 542 mg/100 g, revealing significant differences among the samples. Mature fruits exhibited higher carotenoid concentrations than immature fruits from the same year, with variations depending on the accession. The mature KN pulp from the 2026 harvest showed the highest values ​​for ABTS (10.78 ± 1.13 µmol TEAC/g) and DPPH (4.35 ± 0.73 µmol TEAC/g). In contrast, the highest antioxidant capacity, as measured by the ORAC-FL assay, was observed in immature KN (accession 2025) (14.42 ± 1.29), followed by mature KN (13.89 ± 1.16) and mature KR (13.72 ± 0.58) from the same harvest. Differences between assays suggest that the antioxidant response depends on the composition of the samples and the specific reaction mechanisms being evaluated. Greater carotenoid accumulation during ripening did not necessarily translate into a stronger antioxidant response across all assays, highlighting the potential contribution of various other metabolites. Principal component analysis (PCA) identified both the accession and the stage of maturity as significant factors in differentiating antioxidant profiles. These findings underscore the importance of selecting specific accessions and maturity stages based on the bioactive compounds of interest; this provides criteria for optimizing the technological utilization of “kurugua” and promoting its valorization as a native food resource with the potential for the development of functional ingredients.

Acknowledgements: The authors gratefully acknowledge the support of the VALSE-Food Network. This work was supported by project PIN01-698 co-financed by the Consejo Nacional de Ciencia y Tecnología (CONACYT) with support from the FEEI.