Freeze dryer is to cool the moisture material in advance and freeze it into a solid, and then sublimate the water vapor directly under vacuum conditions, while the material itself remains in the shelf when it is forzen, so it is the same volume after drying, loose and porous.
Since freeze-drying process is carried out in a low temperature and vacuum environment, so the heat-sensitive ingredients in the product such as proteins, microorganisms and other bioactive ingredients can be protected, the volatile ingredients are less lost, and the product is not easy to oxidize.
