Effect of drying conditions on rehydration kinetics of microwave dried spinach

In the present work, it was aimed to understand the effect of drying conditions (microwave output powers and sample amounts) and rehydration temperature on rehydration kinetics of microwave dried spinach. To determine the kinetic parameters, the rehydration data were fitted to two models, Peleg's and Weibull model. Between these two models proposed, Peleg's model gave a better fit for all rehydration conditions applied. The relationships between the kinetic rate constant of the Peleg's model and the ratio of microwave output power to sample amount; and equilibrium moisture content and the ratio of microwave output power to sample amount were estimated; and gave exponential equations. On the other hand, the activation energy for rehydration kinetic was also calculated using Arrhenius equation and found as 23.84 kJ mol(-1). (C) 2008 Published by Elsevier B.V on behalf of The Institution of Chemical Engineers.