the first type, the whole drying process takes place under vacuum environment and a microwave field is applied to
supply the heat of sublimation required for freeze drying. In the second type, the drying process was divided into two stages, (i) freeze drying followed by (ii) microwave/vacuum microwave drying (Duan et al.,2010a). Freeze drying combined with microwaves offers advantageslike reduced processing time and better product quality (Zhang et al.,2006).