BARU PULP (Dipteryx alata Vog.): PROXIMATE COMPOSITION, EXTRACTION KINETICS, AND MASS TRANSFER MODELING OF ULTRASOUND-ASSISTED BIOACTIVE COMPOUNDS EXTRACTION

The pulp of baru (Dipteryx alata Vog.), a fruit native to the Brazilian Cerrado, contains dietary fiber and other constituents that may support the valorization of this biomass. Ultrasound-assisted extraction (UAE) can enhance mass transfer through acoustic cavitation. This study aimed to characterize baru flour and evaluate the extraction kinetics of overall extraction yield and total reducing capacity during UAE. Dried, seedless fruits were mechanically processed to separate the pulp from the woody endocarp, producing baru flour (BF). Moisture, protein, ash, lipids, fiber, carbohydrates, and starch were determined using AOAC methods. For extraction, 2.5 g of BF was mixed with 50 mL of 50% (w/w) ethanol and treated with a 13-mm titanium probe operating at 20 kHz and a nominal power of 500 W for up to 30 min. Overall extraction yield (X₀) was determined gravimetrically after drying to constant mass. Total reducing capacity (TRC) was measured by the Folin–Ciocalteu method at 765 nm and expressed as mg gallic acid equivalents per gram of flour (mg GAE/g BF). Piecewise linear spline models were fitted to describe the extraction kinetics. Processing 26.975 kg of fruits yielded 8.095 kg of BF. The flour contained 11.42 ± 1.05% moisture, 3.49 ± 0.43% lipids, 5.61 ± 0.14% protein, 2.69 ± 0.01% ash, 41.68 ± 1.48% fiber, 35.11% carbohydrates, and 11.57 ± 1.18% starch. Between 2 and 30 min, X₀ increased from 40.93 ± 2.15% to 53.31 ± 1.10%, while TRC increased from 2.21 ± 0.39 to 30.34 ± 0.49 mg GAE/g BF. The spline models showed good fits, with R² = 0.9889 for X₀ and R² = 0.9921 for TRC. Estimated change points occurred at 2.15 and 13.75 min for X₀ and at 18.72 min for TRC. X₀ and TRC were strongly correlated (r = 0.9863; R² = 0.9728), suggesting that overall solubilization was associated with the recovery of reducing compounds under the conditions tested. The high fiber content indicates potential for further valorization of baru pulp, while the kinetic models identify changes in extraction behavior that may inform process optimization. UAE with 50% ethanol therefore provided a useful basis for characterizing extraction performance and supporting future process development and scale-up.

Funding: Brazilian National Council for Scientific and Technological Development (CNPq), Grant No. 133657/2025-6. The authors also acknowledge the University of São Paulo (USP) for hosting the research.