Effect of ultrasound on banana cv Pacovan drying kinetics

The aim of this work was to study and to model the drying kinetics of fresh and ultrasonic pretreated banana cv Pacovan using the diffusional model (Fick's second law) and an empirical two parameters model (Page model). The pretreatment was carried out in an ultrasonic bath at 30 degrees C. The drying process was carried out in a fixed bed dryer at two different temperatures (50 and 70 degrees C) and 3.0 m/s air velocity. Page empirical model provided the best simulation of the drying curves. The diffusional model was used to describe the moisture transfer and the effective diffusivities of water were determined and were in the order of 10(-9) m(2)/s. These diffusivities increased with increasing temperature and with the application of ultrasound, while the process time reduced, which can represent an economy of energy, since air drying is cost intensive. (C) 2009 Elsevier Ltd. All rights reserved.