Measurement of the wet-mass, moisture content, volume and density of single wheat grain kernels

The development of microwave techniques and a separate gas displacement method to measure the wet-mass, moisture content, volume and hence density of single wheat grain kernels are described. The perturbation of the circularly symmetric TM₀₁₀ mode inside a cylindrical cavity is used with a linear model to determine the single grain moisture content and wet-mass. A bellows loading mechanism is used with a calibrated gas-displacement pressure transducer to produce the volume data and hence grain density. Initially, a waveguide cell is used to evaluate the complex permittivity of compressed wheat and this data is used together with the finite element method to design the microwave cavity.