Adzuki beans often suffer from the inclusion of "stony beans" which lack the ability to absorb water. These beans can reduce the overall quality of an entire bean lot. At present, no nondestructive technique exists for separating these beans from their moisture-absorbing counterparts. There have, however, been reports that the moisture content of such "stony beans" is lower than that of normal beans. This study thus attempted to measure adzuki bean moisture content using a microwave sensor and a cavity resonator. Adzuki beans were placed in the center of the cavity resonator, and their moisture content was measured by determining the resonant frequency and the level of reflected waves from the cavity. both of which are a function of the bean's dimensions and moisture content.

Using this method, moisture content for adzuki beans containing moisture levels between 8% and I8% was determined with an uncertainty of 1.2% at the 95% confidence level.