Assessment of Real-Time, In-Shell Kernel Moisture Content Monitoring with a Microwave Moisture Meter during Peanut Drying

Abstract

Abstract. The present-day peanut drying process lacks the capability of in-situ kernel moisture content determination in real-time. Samples of peanut pods have to be taken from the drying trailer, cleaned and shelled by an operator to test for the kernel moisture content. The frequency with which the operator samples the peanuts in the drying trailer to determine kernel moisture content determines the accuracy of the drying process in reaching the targeted kernel moisture content. However, by using a microwave moisture meter, developed within USDA ARS and operating at power levels of a few milliwatts, the moisture content of the peanut kernel can be determined without having to shell the peanut pods. An automated quarter-scale drying system, equipped with the microwave meter, was developed and tested, and it has demonstrated effective control of the drying process and accurate real-time monitoring of kernel moisture content. The objective of this study was to evaluate the performance of the drying system with varying initial kernel moisture contents and atmospheric conditions. Therefore, three trials were run where such conditions were varied. Analysis of variance was performed, and standard errors of prediction were evaluated to compare the kernel moisture content values predicted by the microwave moisture meter to those determined by the oven method. In-shell kernel moisture content was determined in real-time with a standard error of performance ≤ 0.55% moisture when compared to the reference oven-drying method. Overall evaluation demonstrated that the automated drying system is an effective solution for user-independent dryer control and real-time, in-shell kernel moisture content monitoring.