13-10 |
Exploring the disinfection of fungal spores in corn meal using selective IR heating technique |
S. JUN and J. M. K. Irudayaraj. Dept. of Agricultural & Biological Engineering, Pennsylvania State Univ., 107 Agricultural Engineering Bldg., University Park, PA 16802 Selective Infrared (IR) is a novel method to enable the differential heating of various food components, which has never been reported in food processing field. It was applied to corn meal in order to disinfect fungal spores of Aspergillus niger and Fusarium proliferatum. Controlled radiation was shown to stimulate the specific optical response of the targeted object, based upon the coincidence between the IR spectral distribution and the IR absorptivity of food. Discrepancy of absorptivities between pure and infected corn meal was examined using FTIR spectrometer and applied for determination of the IR spectral range. It was observed that for infected corn meal, the peak magnitude increased in the spectral range between 5.88 and 6.66 mm, which relates to the protein band (amide II region). Hypothesizing that selective heating would be able to denature the protein component relevant to spore growth, the optical filter to satisfy this spectral range was chosen and installed to the IR heating system. At the same energy basis filtered IR radiation, whose spectral range is more specific for protein denaturation, inactivated the growth of fungal spores more than the normal IR radiation by about 0.4 log reduction in 5 min. The sample temperature measured was even lower than those previously reported by about 50 oC. The statistical analysis using MANOVA verified that there were significant differences between filtered and normal IR heating, with F values of 7.38 and 7.92 for Aspergillus niger and Fusarium proliferatum, respectively. Selective IR heating technique has great potential for use in food industry to minimize microbial infection by specifically targeting the microorganism with minimal impact on the functional quality of foods.
Session 13, Food Engineering: Thermal processes
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