Water (H2O) has three different states, namaly solid、liquid and gas. The three states 
can change and co-exist. When the vapor pressure is above 611 Pa., ice melts into water 
and water will change into vapor. When the temperature is 0.01 centigrade and the water 
pressure is 610.5 Pa(4.58mmHg),water, ice and vapor can co-exist and balance with each 
other. When the vapor pressure is below 611 Pa. ice can sublimate into vapor, making the 
matter become sponge whithout damaging its shape. This is basic theory of freeze-dry.

2、What is freeze-dry food (FD food)?

FD food is made by quickly freeing dried in vacuum containers. In the vacuum, water 
will sublimate into vapor, making the dry food. This kind of food is good in color、
fragrance、flavor and shape and keeping the vitamin and protein in the food. Before 
eating you can change it into the fresh food in some minutes.

3、What is the feature of FD food compared with other foods?

Water will become vapor if it receives enough heat, so do ice. The former is called 
evaporation and the latter is called sublimation. Air-dry is evaporation, Freeze-dry 
is sublimation, FD food is formed in the way of low temperature and vacuum, so that 
its shape, color and flavor remains undamaged. Also he nourishments remains the same. 
It can return to normal appearance easily. It has no restriction for kinds of foods. It can 
make vegetables、meat、milk、juice and so on into freeze-dry foods.It can also make 
fungi and pilose antler into FD medicine.