Freeze-dry
Freeze-dry (frēz"-drī`) , transitive verb
This is a relatively gently drying process used to preserve food or sensitive biological materials. For biochemical materials, the term lyophilize is often used.
to remove the moisture from (for example food) by first freezing and then subjecting to a high vacuum; -- used as a mild method for drying foods or chemicals while causing little decomposition, in contrast to heat-drying.