Abstract:
Abstract
Food processing by microwave heating has become attractive lately, as it is a volume, uniform, shorter time heating when compared to conventional methods. For example, here can be mentioned pre-cooking of rice, blanching of peas and corn, or enzyme-inactivation of wheat and mustard seeds. The development of this industry has been essentially empirical, as many interacting physical phenomena are involved. When modelling research is carried over, accurate knowledge of dielectric properties of food is required.
The dielectric properties of matériái characterise the wave-material interaction. They are usually represented by the complex number, = ’ - j’’, where the real part, ’, is associated with the ability of a material to store electric-field energy and the imaginary part, ’’,reflects the ability of a material to dissipate electric energy in the formof heat.
In this paper, two waveguide methods for measuring the dielectric constant of non-magnetic materials at 2.45 GHz frequency are reviewed, and experimental results for mustard seeds we are presented as a function of the bulk density and the moisture content.
