Mathematical Modeling of Convective Drying Acerola (malpighia Emarginata) Residue in Different Thicknesses

Abstract

The increasing demand and processing capacity of the fruit processing industries generates a huge amount of waste. Brazil stands out as a producer and exporter of acerola (Malpighia emarginata). One of the alternatives to add value to this by-product and contribute to minimizing environmental impacts from its disposal is drying. The drying was carried out with forced air circulation at a speed of 2,20 m s-1 and a temperature of 75 ºC, in thicknesses of 3, 4, 5 and 6 mm. The adjustment of the models to the experimental data was performed with Software Statistica 10.0. The effective diffusion coefficient, in the order of 10-10 m2 s-1, is adequate and did not present a significant difference, among the three major thicknesses. Drying parameters of design and operation were analyzed by mathematical models of Page, Lewis and Midilli, using performance indicators as accuracy (Af) and noise factors (Bf), mean square error (RMSE) and standard error of prediction (% SEP), associated with each model. All the models present a good adjustment. Despite the greater accuracy of the Midilli model, the Page model is considered more appropriate for process purposes, since it is necessary to adjust only two parameters.