Mathematical Simulation of the Effective Diffusivity of Water during Drying of Papaya

A simplified equation for drying kinetics has been used to determine an expression for the effective moisture diffusivity of papaya (Carica papaya L.). The mathematical description of moisture diffusivity includes exponential and Arrhenius type terms to express its dependence on moisture and temperature, respectively. Moreover, product shrinkage is considered during the model coefficients estimation. Experimental parts included the moisture and temperature measurements in papaya slabs with a thicknesses of 0.005, 0.01, and 0.015 m during drying at various air temperatures (50, 60, and 70°C) and 1.0 m·s−1 of air velocity. Results showed that the proposed methodology allows obtaining reliable values for effective moisture diffusivity. Additionally, it was demonstrated that the obtained moisture diffusivity expression is able to accurately reproduce the experimental behavior, including the bends on the drying curves, when used jointly with a detailed model.