A density-independent microwave moisture meter for heterogeneous foodstuffs

Abstract Experiments on unground fish meal have been performed using a prototype microwave moisture meter: This device, which was claimed to be density-independent for loose materials such as fibres and powders, measures two microwave parameters simultaneously. A full examination of its performance over a wide range of density and moisture content whilst not entirely justifying this claim shows that it is considerably better than any instrument based on single parameter measurement. For very heterogeneous materials the moisture content could be determined to within ±0·6% moisture content or better-depending on the range of density variation experienced in practice.