Moisture Determination In Individual Grain Kernels And Nuts By Rf Impedance And Microwave Resonator Measurements

A bstract--The moisture contents of individual field corn, popcorn, and peanut kernels, single in-shell pecan nuts and pecan kernel halives were determined by measurement of the impedance of a small parallel-plate capacitor with the kernel or nut between and in contact with the plates at two frequencies between 1 and 5 MHz. Standard errors of performance ranged from 0.4 to 0.7 percent moisture, and the method appears usefull for practical application. Similar performance was achieved with soybean seeds and corn and peanut kernels by measurements of frequency shift and changes in transmission characterisics of microwave resonant cavities in the 3 to 6 GHz range when the seeds or kernels were inserted into the cavity.