CRYOPROTECTION OF EMULSIONS IN FREEZE-DRYING - FREEZING PROCESS ANALYSIS

We report the effects of different freeze/thawing processes on oil-in- water emulsions. The influence of the oil phase concentration, the coo ling rate and the addition of carbohydrates as cryoprotectors were inv estigated. It appears that a slow cooling rate and the addition of cry oprotectants which do not crystallize during freeze/thawing have the b est stabilizing effects. These stabilizing effects were attributed to the amorphous state of the cryoprotectants and the lower mechanical st ress due to the dow cooling rate. Heat treatment before thawing causes crystallization and decreases the stabilizing effects. These results show the importance of crystalline state of additives used as cryoprot ectants during freeze/thawing.