FREEZE-DRIED Eugenia stipitata PULP: BIOACTIVE PROFILE, ANTIOXIDANT POTENTIAL, AND STRUCTURAL CHARACTERIZATION

Amazonian biodiversity encompasses numerous fruit species with remarkable potential as sources of bioactive compounds, offering valuable opportunities for the development of functional ingredients. Among these species, araçá-boi (Eugenia stipitata) has attracted increasing attention due to its high content of vitamin C and phenolic compounds, which are associated with remarkable antioxidant, anti-inflammatory, and antiproliferative activities. However, its high perishability and limited commercial exploitation restrict its incorporation into higher value-added production chains. In this context, freeze-drying emerges as a promising strategy to improve pulp stability, preserve its bioactive compounds, and expand its potential application as a functional ingredient. Accordingly, this study aimed to characterize the bioactive composition, antioxidant capacity, and structural properties of freeze-dried E. stipitata pulp. Ripe fruits were collected in Ituberá, Bahia, Brazil (13°44′ S, 39°09′ W). After freeze-drying, the pulp was analyzed for total phenolic and total flavonoid contents, as well as antioxidant capacity using the ORAC, DPPH, ABTS, and FRAP assays. Structural properties were evaluated by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The freeze-dried pulp exhibited a relevant bioactive profile, with total phenolic content of 9.94 ± 0.44 mg GAE g⁻¹ dw and total flavonoid content of 4.08 ± 0.66 mg CAE g⁻¹ dw, together with high antioxidant capacity determined by the ORAC (162.80 ± 12.22 μmol TE g⁻¹ dw), DPPH (155.11 ± 4.23 μmol TE g⁻¹ dw), FRAP (148.41 ± 8.80 μmol TE g⁻¹ dw), and ABTS (78.33 ± 0.15 μmol TE g⁻¹ dw) assays. The FTIR spectrum exhibited a broad band at approximately 3400 cm⁻¹, attributed to the stretching vibration of hydroxyl (O–H) groups present in phenolic compounds, polysaccharides, and adsorbed water. The bands observed around 2920 cm⁻¹ were assigned to the C–H stretching of aliphatic groups. A prominent band at approximately 1730 cm⁻¹ indicated carbonyl (C=O) stretching, characteristic of organic acids, esters, and pectins. Absorptions between 1600 and 1510 cm⁻¹ were attributed to vibrations of the aromatic backbone of phenolic compounds. In the 1200–1000 cm⁻¹ region, bands associated with C–O and C–O–C stretching were observed, indicating the presence of structural carbohydrates and cell wall polysaccharides. SEM micrographs revealed a highly porous, rough, and irregular matrix composed of lamellar structures characteristic of the freeze-drying process. This structural organization suggests a high specific surface area, which may enhance the rehydration capacity of the material. Collectively, these findings demonstrate that freeze-drying preserves the key chemical and structural attributes of E. stipitata pulp, yielding a natural ingredient with remarkable antioxidant capacity. This study contributes to the scientific and technological valorization of this underutilized Amazonian species and expands its potential for application in functional food formulations and the development of high value-added products.