Modeling of banana convective drying by the drying characteristic curve (DCC) method

Experimental convective drying tests of banana have been carried out for different air conditions to show the influence of air temperature, absolute humidity and speed on the drying rate. The analysis of the drying rate evolution as a function of product water content enables the identification of fourth drying phases: temperature rising (phase 1), exponentially decreasing drying rate (phase 2), linearly decreasing drying rate (phase 3) and very low drying rate (phase 4). The temperature rising phase I being very short and the last phase 4 being not reached during typical drying, the drying characteristic curve (DCC) has been represented by two different mathematical functions fitting phases 2 and 3. Their parameters have been determined by minimization of the quadratic errors between experimental and theoretical curves. It leads to a unique curve (the DCC) representing all air drying conditions the integration of which enables the calculation of the product water content with a maximum error of 0.09 between experimental and simulated values.