Drying with the help of sun and wind is one of the oldest methods of food preservation known to man, but artificial drying, or dehydration, has been developed and used extensively only during the last two decades. The problem in dehydration is that the water content must be decreased sufficiently to maintain the stability of the product by retarding the rates of deteriorative biochemical, microbiological, and enzymatic reactions during subsequent storage. At the same time irreversible changes should not be brought about.