Emerging Technologies for Food Processing, 2nd Edition

29.3. The Physical Characteristics of Ice

The freezing point of water is 0 °C, which makes this the melting temperature of ice as well. In aqueous solutions, the melting point (equilibrium freezing point) is always depressed colligatively by 1.86 °C/molal solute (see Mazur, 1984). By adding osmolytes to a solution, the vapor pressure is lowered, following Raoult's law. However, this only really has an effect on the liquid phase, because ice formation excludes nearly all foreign molecules. This decrease in the vapor pressure of only one phase is what causes the freezing point depression as a function of the osmolytes. The effect of the osmolytes is often denominated as a decrease in the chemical potential. The phase with the lowest chemical potential ...