Influence of Temperature and Total Soluble Solids on Thermo-Physical Properties of Pomegranate Juice

摘要

Determination of thermo-physical properties of pomegranate (Punica granatum L.) juice is essential for examining, controlling, and developing numerical models of processes such as drying and concentrating. These properties are affected by changing the percentage of soluble solid content (oBrix) and temperature. Thermophysical properties of pomegranate juice including density, specific heat and thermal conductivity at temperature range from 25 to 70oC and at the three levels of soluble solid content (12, 40 and 65 oBrix) were investigated in this research. Thermal conductivity, density, and specific heat were measured by co-axial cylinder, volumetric pycnometer and differential scanning calorimeter (DSC), respectively. Results from regression analysis of output data showed that both temperature and solid content affected the thermo-physical properties of pomegranate juice; however, the soluble solid content exhibited a greater effect. By increasing soluble solid content and decreasing temperature, thermals conductivity and specific heat have been reduced linearly but density increased during augment of soluble solid content or decrease of temperature.