Preservation of Biological Materials by Freezedrying

摘要

The feasibility of freeze-dehydrating biological materials by extracting frozen moisture with dry cryogenic liquids in the presence of dessicants was investigated. Freeze-dehydration of hydrated gelatin capsules in liquid nitrogen and liquid nitrous oxide proceeded too slowly to be evaluated. Dehydration was feasible in ethyl ether and ethyl alcohol at dry ice-alcohol temperature (-78.5C). The presence of a dessicant in the de hydration system was found to be essential for complete drying. A sequential vacuum freeze drying-nitrous oxide critical point dehydration technique was used to obtain porous dehydrated meat tissue. Dehydration of partially freeze dried meat tissue (10% residual moisture) was also carried to completion (