ABSTRACT
The discussion in the previous chapters concerned gaseous systems, but in food science the reactions take place primarily in liquid solutions. It is thus necessary to give some attention to the peculiarities of the thermodynamic behavior of solutions. As mentioned in the previous paragraph, the motion of a liquid molecule is restricted by means of bonds with other molecules in its proximity. Such molecules cannot be readily released from their liquid matrix to become gaseous. In this respect, the transition from liquid to gas for a group of molecules is an interplay between the reduction in enthalpy ΔH due to the formation of bonds (which favors the liquid state) and the increase in entropic contribution TΔS due to the increase in temperature (which favors maximization of entropy, thus spreading the molecules in their gas form). As temperature increases, so does TΔS, driving the system toward volatilization.
