t has been reported that almost all of the drying of biological products takes place in the falling rate period (Madamba et al., 1996). However, Mowlah, Takano, Kamoi and Obara (1983) have found both constant and falling rate periods in dehydration of bananas at 60°C in an air circulated oven. Air in the oven is saturated, by the time, and forms a thick film around the food that prevents effective separation of the evaporated moisture from the food. This may be the reason for existence of a constant rate period in their study. A high initial drying rate, with higher rates at lower thicknesses, was observed (Fig. 3). All the samples tended to dry slowly at the last stages of drying, presumably due to collapse (shrinkage) of the banana structure resulting in low transport rate of water and prolonged drying time (Kostaropoulos & Saravacos, 1995).