The vacuum contact‐plate dehydration of foodstuffs. II.—equipment

Abstract

Abstract On account of the lower temperatures of vaporization at reduced pressures, vacuum evaporators and vacuum dryers have for long been in use for the drying of thermally unstable materials. During the Second World War attempts were made to dehydrate foodstuffs using vacuum‐drying equipment of the types then available but, except in the case of finely divided materials, the results were unsatisfactory. The equipment described in this article comprises a large steel vacuum cabinet accommodating 21 trays enabling about a ton of material to be dried per batch. The movable heating plates, arranged in such a manner as to maintain good thermal contact with foodstuff undergoing dehydration, are responsible, more than any other feature of the plant, for the successful drying of meat steaks, fish fillets, sliced root vegetables and certain whole fruits.