Dehydration of food and pharmaceutical solns - by freezing, separation of ice crystals, and evaporation of the liquid

摘要

Process for dehydrating aqs. food and pharmaceutical prods. in which (a) the prod. is frozen so that the water freezes into crystals or platelets, (b) the residual liq. and ice are sepd. by centrifuging in a thin layer, (c) the liq. is concentrated by heating. The process is suitable for any material of vegetable origin such as fruit juices, and infusions from seeds, leaves and flowers. It is partic, useful for dehydrating tea or coffee infusions. The method does not cause loss of flavour. The process is pref. effected in a non-oxidising atmosphere with the final evapn. taking plate in vacuo esp. with high frequency dielectric or microwave heating.