Development of Radiant Heating System and Methods for Drying and MicrobialDecontamination of Corn

摘要

Convective heated air drying of corn is energy intensive and not metered to inactivate harmful mold spores, especially those responsible for development of mycotoxins. The objective of this study was to investigate the effectiveness of infrared (IR) heating of corn on a vibrating conveyor belt to achieve rapid and simultaneous corn drying and microbial decontamination. A newly-built, single-zone, continuous IR heating system, which utilized catalytic IR heaters powered by natural gas, was tested to dry freshly-harvested corn at initial moisture contents (IMCs) of 16%, 20%, and '26% to 13% (wet basis).Tests were conducted at three levels of IR intensities (herein designated as low, medium and high intensities) regulated by gas supply, three intermittent heating durations (30, 50, and 90 seconds), product-to-emitter-gap size of 450 mm, and at set belt vibration intensity and air circulation levels. The implications of the treatments on drying duration and microbial load reduction were determined. Thedurations to dry corn from 16%, 20%, and 26% IMCs to final MC of 13% at the low IR intensity and intermittent heating duration of 90 s were 300, 840 , 870 s, while the corresponding microbial log reductions were 1.1 ,0.3 and 0.3 respectively. The duration to dry corn from 16%, 20%, and 26% IMCs to final MC of 13% at the high IR intensity and intermittent heating duration of 90 s were 210, 510 and 570 s, while the corresponding microbial log reductions were 1.3, 0.7, and 2.6, respectively. Based on theresults, IR heating of corn holds promise as a rapid drying method with potential benefits of microbial decontamination.