The influence of microwave-assisted drying techniques on the rehydration behavior of blueberries (Vaccinium corymbosum L.)

Abstract

The aim of this study was to determine the effect of: (a) different drying methods, (b) hot air temperature in a convection oven, and (c) the moisture content of fruits dehydrated by multi-stage drying which involves a transition between different stages of drying, on the rehydration kinetics of dry blueberries. Models describing rehydration kinetics were also studied. Blueberries dehydrated by multi-stage microwave-assisted drying, which involved a hot air pre-drying step at 80°C until the achievement of a moisture content of 1.95kgH2Okg−1DM, were characterized by significantly higher rates of initial and successive rehydration as well as smaller initial loss of soluble solids in comparison with the samples dried by other methods. The highest initial rehydration rate and the smallest loss of soluble solids after 30min of soaking were determined at 0.46min−1 and 0.29kgDMkg−1DM, respectively. The Peleg model and the first-order-kinetic model fit the experimental data well.