Dielectric properties of pumpable food materials at 915 MHz

Dielectric properties of pumpable food materials having a potential to be processed using a continuous flow microwave heating system were measured at 915 MHz and in the temperature range of 10-90 degrees C. The products considered in this study were milk and dairy products (epsilon': 70.0 to 50.8 and epsilon '': 14.7 to 41.3), ready to eat puddings (epsilon': 69.4 to 52.1 and epsilon '': 17.2 to 23.8), soy beverages (epsilon': 75.4 to 60.8 and epsilon'': 9.0 to 19.8), and avocado products (epsilon': 51.6 to 39.0 and epsilon '': 17.7 to 67.5). The results showed that the dielectric constant decreased with an increase in temperature and the dielectric loss factor increased with an increase in temperature. Polynomial correlations for the dependence of dielectric properties on temperature were developed. The dielectric properties measured in this study are important parameters for designing a continuous flow microwave heating system for processing pumpable food materials.