INFLUENCE OF RIPENING STAGE ON THE PHENOLIC CONTENT AND ANTIOXIDANT CAPACITY OF ‘PALMER’ MANGO PEEL FLOUR

Mango (Mangifera indica L.) is one of the most widely produced and consumed fruits in Brazil, and its processing generates substantial amounts of by-products, particularly peel, which represents a valuable source of phenolic compounds with antioxidant potential. However, ripening induces metabolic changes that may alter the chemical composition and bioactive profile of mango peel, thereby influencing its suitability for various food applications. Understanding these variations is essential to establishing strategies for the sustainable valorization of mango processing by-products. This study aimed to evaluate the effect of ripening stage on total phenolic content and antioxidant capacity of flours produced from mango peels from Palmer cultivar. Unripe and ripe fruits rejected for commercialization, which represent losses in the mango production chain, were used as raw materials. After the fruit was sanitized, it was peeled manually and the peels were dried, milled, and characterized regarding total phenolic content (Folin–Ciocalteu method), antioxidant capacity by the ABTS assay, and free radical scavenging activity by the DPPH assay (IC₅₀). Significant differences (p < 0.05) were observed between ripening stages. Green mango peel flour exhibited approximately fivefold higher total phenolic content than ripe mango peel flour (12 587.41 and 2 574.71 mg GAE 100 g⁻¹, respectively), along with greater antioxidant capacity determined by the ABTS assay (417.86 and 262.54 µmol TE g⁻¹, respectively). Similarly, green peel flour showed a lower IC₅₀ value in the DPPH assay (0.49 mg mL⁻¹) compared with ripe peel flour (3.64 mg mL⁻¹), indicating higher efficiency in scavenging free radicals. The higher accumulation of phenolic compounds in green peel is consistent with the protective role attributed to these metabolites during the early stages of fruit development, when they contribute to defense mechanisms against environmental stresses. The reduction observed during ripening may be associated with metabolic transformations and oxidative processes that affect phenolic stability, thereby decreasing antioxidant capacity. Nevertheless, the phenolic content and antioxidant activity detected in both flours demonstrate that green and ripe mango peels have potential for valorization, differing mainly in the intensity of their bioactive properties. In conclusion, the ripening stage significantly influences the phenolic content and antioxidant capacity of Palmer mango peel. Although both materials represent promising agro-industrial by-products, green peel flour exhibited superior bioactive potential and may be prioritized for applications focused on maximizing phenolic recovery and antioxidant functionality. These findings highlight the ripening stage as an important criterion for selecting mango peel as a raw material according to the intended application, contributing to the development of value-added ingredients and the sustainable valorization of mango processing residues.

Acknowledgments: CAPES (Grant No. 88887.992642/2024-00) and CNPq (Grant No. 302848/2021-5).