PHYSICAL AND FUNCTIONAL PROPERTIES OF JABUTICABA PEEL FLOUR OBTAINED USING DIFFERENT DRYING PROCESSES

The complex mechanism of water diffusion in agricultural products, influenced by both chemical composition and physical structure, requires optimization for functional ingredient development. This study aimed to model the drying kinetics of jabuticaba (Myrciaria cauliflora Berg.) peels and determine their effective diffusivity coefficients, with the goal of producing a functional flour retaining valuable nutritional and bioactive compounds, particularly anthocyanins. Fresh peels were dried in a convective dryer under controlled conditions (40°C, 55°C, 70°C; air speed: 45 m s⁻¹). The resulting flour was characterized for proximate composition, water activity, pH, titratable acidity, soluble solids, total phenolic compounds, and antioxidant activities (DPPH and ABTS methods), and total anthocyanins. Both three-term and five-term mathematical models satisfactorily described the drying kinetics, with the five-term model showing the best fit (R² values consistently near 1.00) across all temperatures. Higher effective diffusivity coefficients were observed at 70°C, indicating faster water removal. The moisture content of the peels decreased significantly with increasing drying temperature, while acidity generally increased. The resulting jabuticaba peel flour demonstrated a remarkable crude fiber content of 61.18 g/100g, highlighting its dietary potential. Regarding bioactive compounds, 50% acetone proved most effective for extracting phenolic compounds from the 70°C dried peel. Antioxidant activity assays showed that the 70°C dried peel exhibited the highest DPPH radical scavenging capacity (e.g., 36243 µmol Trolox g⁻¹ with 50% acetone) and ABTS radical scavenging capacity (e.g., 785.63 µmol Trolox g⁻¹ with acetone + 50% methanol mixture). The 70°C drying temperature also yielded the highest total anthocyanin content in the dried peel and subsequent flour, demonstrating effective compound retention. In conclusion, the optimized drying process at 70°C successfully produced jabuticaba peel flour with high nutritional and functional content. This co-product presents significant potential for incorporation into food products with functional claims, offering a sustainable approach to valorizing agricultural waste.