Solubility of D-Galactose, D-Talose, and D-Tagatose in Aqueous Ethanol at Low Temperature

Abstract

The solubility of d-galactose, d-tagatose, and d-talose in aqueous ethanol (20 – 80 wt%) was measured in the temperature range of −30°C to 20°C. The solubility of each sugar decreased upon increasing the ethanol concentration and decreasing the temperature. The solubility of d-talose and d-tagatose was higher than that of d-galactose under all conditions. The temperature dependence of the solubility of each hexose can be expressed by the van't Hoff equation. The dissolution enthalpy of each hexose decreased upon increasing the ethanol concentration. The dissolution enthalpy of d-talose was higher than that of d-galactose and d-tagatose.