Effects of temperature and concentration on specific volume, vapor pressure and enthalpy of vaporization of fruit juice

The densities and the vapor pressures of two fruit juices (orange juice and apple juice) of concentrations ranging 10%similar to 60% (w/w) were measur ed at temperatures between 10 degrees C similar to 60 degrees C by the pycn ometer method and a static met hod, respectively. On the basis of the measu red results, the effects of concentration and temperature on the specific v olume, which was the reciprocal of density, and on the vapor pressure were investigated. The specific volume and the vapor pressure were written as a function of both temperature and concentration, respectively. These equatio ns were used in conjunction with the Clapeyron equation to calculate the en thalpies of vaporization for two fruit juices. Finally, the obtained result s were compared with the results calculated from an empirical equation, whi ch is convenient to the practical use.