Calibration Algorithm for Rapid and Nondestructive Moisture Sensing in In-Shell Nuts

A new calibration algorithm is presented for instantaneous and nondestructive determination of moisture contents of in-shell nuts and kernels from measurement of the dielectric properties of in-shell nuts at a single microwave frequency. The new calibration algorithm relies on the use of a density-independent function, expressed in terms of the dielectric properties, and the existence of a direct relationship between the in-shell nut oven moisture content and kernel oven moisture content. Results of measurement by using a microwave moisture sensor operating at 5.8 GHz are presented, and kernel moisture calibration equations are established for peanuts and almonds.