Drying kinetics and the effect of blanching pretreatment on banana

Resumo

The aim of this study was to estimate and select the drying kinetic model of thin-layer drying of banana slices and the effect of blanching pretreatment. In order, 16 semi-theoretical and/or empirical models were applied to the experimental data and compared according their coefficients of determination (R²), sum squared errors (SSE), and root mean square error (RMSE), which were predicted by non-linear regression analysis. Banana slices were subjected to the thermal blanching treatment, and then the samples were dried at 50 °C and 60°C for a period of 630 min. Chromatic characterization and shrinkage analysis were performed. Among the thin-layer drying models considered to determine the kinetic drying parameters, the semitheorical Two-term model gave the best fit for all drying conditions. Effective moisture diffusivity varied from 8.25 × 10⁻¹¹ m²s^-1 to 2.26 × 10⁻¹⁰ m²s^-1 over the temperature range of the study. The increase in temperature led to a 60% average volume reduction. For color, the parameters L* and b* decreased, and a* increased in relation to the temperature increase, and blanching had a positive effect.