Freezing and Eutectic Points of an Aqueous Amino Acid Solution Containing Ethanol, and the Effect of Ethanol Addition on the Freeze Concentration Process

Abstract

The freezing point curves and solubility curves for an aqueous solution of glycine or sodium glutamate with or without ethanol were measured, and the eutectic points of these solutions were estimated by the intersection of both curves. The addition of ethanol lowered the freezing point, the solubility, the eutectic temperature and the concentration of each amino acid solution. On the basis of these results, the freeze concentration of an aqueous solution of glycine was attempted on a pilot plant scale. The addition of ethanol greatly reduced the loss of glycine which was carried over during the separation of ice crystals by centrifuging.