ASABE Technical Library - Abstract

Abstract. The typical convective heated air drying method for corn is an energy intensive process not metered to inactivate harmful mold spores. In addition, prolonged drying durations associated with the drying method may allow mold growth in the product leading to development of mycotoxins. The objective of this study was to investigate the effectiveness of utilizing a newly-built continuous-flow infrared (IR) heating system to achieve rapid corn drying and decontamination, and also evaluate the implications of the new process on dried product quality. A newly-built, single-zone, continuous-flow IR heating system, which utilized catalytic IR heaters powered by natural gas, was tested to dry freshly-harvested corn at initial moisture contents (MC) of 24% to 13% (wet basis). The new system with a modular design allowed adjustment of process parameters such as belt speed (10 Hz to 60 Hz), IR intensity (2.39, 3.78 and 5.55 kW/m2 which corresponds to low, medium and high, respectively), belt vibration intensity, air circulation level within the drying zone, and product-to-emitter-gap size. Tests were conducted at three levels of IR intensity (low, medium and high) and three intermittent heating duration (30 s, 50 s, and 180 s) for a set of belt vibration intensity, air circulation level, and product-to-emitter-gap size of 450 mm. The total duration required to dry corn from 24% to 13% MC at high IR intensity and intermittent heating duration of 30 s was 395 s. The microbial load on corn at 24% MC when dried at the high intensity and intermittent heating duration of 180 s to 13% MC were significantly reduced from 4.79 ± 0.15 to 2.03 ± 1.2 log CFU/ g of corn. Compared to the freshly-harvested corn, the treatments did not have any impact on dried product color. Based on the results, IR drying of corn holds promise as a rapid drying method with potential benefits of microbial decontamination which may help the industry prevent mycotoxin development on corn.