Effect of temperature and pretreatment on water diffusion during rehydration of dehydrated mangoes

The kinetics associated with rehydrating dehydrated mangoes was studied at three temperatures: 25, 40, and 60 degrees C. Besides, we studied how rehydration was affected by pretreating the fruit with osmodehydration in either sucrose or glucose before it was thermally dehydrated. We show that rehydration can be interpreted by Fickian diffusion and that the effective water diffusion coefficient is larger at 40 degrees C than at either 25 or 60 degrees C. Consequently, during rehydration of untreated samples at 40 degrees C, the weight gain, water gain, and loss of solids attain optimal values. We found that the rehydration kinetics of mango was not affected by osmodehydration pretreatments in sucrose. However, pretreatment in glucose significantly improved rehydration; for example, the effective diffusion coefficients of the glucose-treated samples were about twice as large as those of the untreated samples. (C) 2009 Elsevier Ltd. All rights reserved.