Evaluation of In-Shell Kernel Moisture Content Monitoring with a Microwave Moisture Meter during Peanut Drying

摘要

Present peanut drying processes lack the capability of kernel moisture content determination in realtime. Samples of peanut pods have to be taken from the drying trailer, cleaned and shelled in order to test for the kernel moisture content. By using amicrowave moisture meter, developed within USDA ARS, the moisture content of the peanut kernel can be determined without having to shell the peanut pods. The microwave moisture meter operates at 5.8 GHz at power levels of a few milliwatts. An automatedquarter-scale drying system, using the microwave meter, was developed and tested successfully. The drying system utilizes the microwave meter in a dynamic setting, one in which the moisture content of the peanut pods and kernels is constantly changing. To evaluate the stability of the real-time kernel moisture content monitoring, peanut-drying trials were run with varying initial kernel moisture contents. During each trial, samples were extracted and shelled to conduct moisture tests by the reference oven drying method. Analysis of variance was performed, and standard errors of performance were evaluated to compare the kernel moisture content values predicted by the microwave moisture meter to those determined by the oven method. Results indicate thatthere were no significant differences between kernel moisture content determined by the microwave meter and by the oven method. Overall evaluation showed that the automated drying system, with microwave moisture meter, is an effective solution for real-time in-shell kernel moisture content monitoring during the drying process.