Secagem híbrida convectiva-infravermelha para a produção de banana-passas

Abstract

The production of dried bananas can reduce post-harvest losses and add value to the product. This study investigated the drying kinetics of bananas by combining infrared radiation at different power levels (140, 160, and 180 W) and heated air convection at different temperatures (50, 60, and 70 °C), along with three intermittence levels (0, 0.333, and 0.667). The final moisture content of the samples ranged from 17% (P = 180 W and T = 70 °C, α = 0) to 57.4% w.b. (P = 160 W, T = 50 °C, α = 0.667). Specific energy consumption (SEC) varied from 23.62 kWh/kgH2O (P = 180 W, T = 70 °C, α = 0.333) to 74.49 kWh/kgH2O (P = 140 W, T = 50 °C), while CO2 emissions (qCO2) ranged between 0.121 and 0.213 mgCO2. The effective diffusivity was estimated between 5.47∙10⁻⁴ and 1.37∙10⁻³ mm²/s, and activation energy ranged from 13.69 to 17.63 kJ/mol. The thermodynamic properties in continuous drying, ΔH (11.95 to 13.41 kJ/mol), ΔS (-259.14 to -258.56 J/mol K), and ΔG (83.65 to 89.89 kJ/mol) were also calculated. The quality of the dried product was evaluated in terms of pH (4.33 to 4.79), soluble solids (28 to 83 °Brix), water activity (0.43 to 0.52), and hardness (2.02 to 39.77 N). The optimal condition (P = 180 W, T = 60 °C, and α = 0.389) achieved an overall desirability of 0.83, indicating a high-quality product within specification limits (Mf, Aw, TSS, and firmness), while maximizing process performance (Def and SEC) and reducing environmental impact (qCO2).