ULTRA-BROADBAND CHARACTERISATION SYSTEM FOR THE DIELECTRIC PROPERTIES OF FOOD MATERIALS

The understanding of the dielectric properties of food material is important for electromagnetic-based treatments from reheating in a domestic microwave oven to sterilization processes. This is due to aspects such as the uniformity and rate of heating of the food being highly dependent upon the dielectric constant and dielectric loss of the food material, with both parameters being intrinsically temperature-dependent. In this work, a method for ultra-broadband (1 Hz to 1.6 GHz) characterisation of food materials is described. The ease of use of this system allows for rapid testing of a food standard – in this case, instant mashed potato – with various combinations of moisture and salt content. In addition to the ultra-broadband measurements, the system also allows for automated temperature sweeps (-100℃ to 300℃). By obtaining these ultra-broadband datasets, additional understanding can be gained of the mechanisms behind the variation of the dielectric properties. One measurement system provides dielectric data covering very different heating applications: – e.g. microwave (0.4 – 5.8 GHz), radio frequency (1 – 100 MHz), ohmic (50 Hz) – as well as measurement and imaging applications.