Vacuum microwave puffing is a technology that is based on the fact that if water inside a product cell evaporates faster than it can escape from that cell through the cellular wall, the pressure inside the cell will increase and that increasing pressure will create a puffing effect It happens under low pressure because low pressure generates more pressure difference. The end-product will have a porosity close to that of freeze-dried products.  It will have a rehydration capacity close to that of freeze-dried products. And it will have a color and taste that is much better than most freeze-dried products, because the puffing time is just a matter of minutes, while freeze drying can take from 8 up to 24 hours.