Drying with the microwave method under vacuum is a modern, efficient method of food preservation.
During vacuum-microwave (VM) drying the energy of microwaves is absorbed by water located in the
whole volume of the material being dried. This creates a large vapour pressure in the centre of the
material, allowing rapid transfer of moisture to the surrounding vacuum and preventing structural
collapse. As a consequence, the rate of drying is considerably higher than in traditional methods of
dehydration. A decisive factor enhancing drying rate is the wattage of microwaves. The puffing
phenomenon, that accompanies the rapid process of dehydration, creates a porous texture of the food and
facilitates obtaining a crispy and delicate texture, and in this way it reduces the product’s density as well
as shrinkage [5].