抄録
In order to get useful information regarding the freeze drying process, macroscopic appearance during freezing and drying were observed on solutions of amino acids exhibiting eutectic behavior. The eutectic crystal structures were observed to take the form of white, densely opaque spots. The velocity of the eutectic crystallization was roughly estimated from the increase of the spots' size and number. The electrical resistance of the solution during freezing was also measured. There existed an optimum temperature range to promote the eutectic crystallization for each solute. Freeze drying of these substances produced very characteristic surfaces and interiors leaving behind the solute crystal portion of the eutectic crystal mixtures. The dried sample had a more concentrated shell, namely, considerable differences in concentration occured between the surface layer and the bulk.
