Rehydration Behavior of Vacuum-Microwave-Dried Potato Cubes

Rehydration properties and microstructure of vacuum-microwave and hot air-dried potato cubes were examined. Two kinds of models were considered to describe the hydration kinetics: a diffusion model for a cube and two empirical equations, Peleg and Weibull. The values of the effective moisture diffusivity of soaked potatoes were in the range 1.1710-9 to 4.7310-9m2/s. The vacuum-microwave drying technique resulted in puffed potato particles characterized by porous microstructure with a network of open cavities and the hot air drying gave the potato particles containing compacted cells with the low amount of open micro-caves. Higher rehydration ability was observed for the samples dried with microwaves under low pressure. Vacuum-microwave drying at 6kPa seems to be the optimal drying condition for potato cubes, ensuring porous microstructure of dried material and low shrinkage of dried potato particles as well as their high recovery properties and rehydration.