What's the technology behind Freeze Dried Foods ?

The bacteria and molds that make food foul or downright toxic can't live without water. Freeze-drying food or drink are freezed firstly at a temperatures in the range of -60 to - I I 0°F  turning its water content to ice and stunning germs in the bargain.The food is heated in a low-pressure chamber,which forces the solid ice molecules to break apart into a gaseous state, skipping the liquid phase. The water vapour is condensed and  pumped from the chamber. This  process is called as sublimation.This process take hours.

What's left is the intact structure of the food, with airy pores where the water was. The lack of water even stops enzymes from rotting. To prevent the food from absorbing more moisture from air ,its packed in airtight container.After some years later, just add water and stir. It's the technology behind instant coffee, dried soup mix, powdered drink and dried-fruit snacks.Freeze -dried foods are compact and light weight as it is emptied of water