29D-5 |
Characterization of radiant energy sources used for food processing |
B. J. LLOYD, B. E. Farkas, and K. M. Keener. Dept. of Food Science, North Carolina State Univ., Schaub Hall, Box 7624, Raleigh, NC 27695-7624 Radiant heating of food products is commonly used in home appliances as well as in large-scale industrial processes. Radiant energy intensity and spectral power distribution are important parameters in the design of a radiant heating system. These parameters indictate the depth of energy penetration into the product as well as its absorption by individual food components, both mechanisms that contribute to the final success of the heating process. The objective of this research was to measure the intensity and spectral distribution of radiant energy emitters common to food processing. An incandescent heat lamp, quartz halogen lamp, metal sheath, and woven quartz fabric painted surface were selected for the study. The intensity of each emitter was measured over a range of radial positions and distances from the emitter's surface using a radiometer. The spectral distribution was determined using two methods: surface temperature assuming Plank's blackbody distribution and FTIR emission spectroscopy for the range of 0.8 to 100+ mm. This approach allowed comparison of theoretical verses measured spectral curves. Results for measured energy intensity showed strong dependence on radial position and distance from the emitter surface with a range of 0 to 5.4 W/m2. The spectral curves from the FTIR analysis closely followed the theoretical spectral curves from Plank's blackbody distribution. This work provides users of radiant food processing equipment spectral curves of the energy impinging on the food material's surface. Manipulation of emitter intensity, spectral distribution, and food composition may then be achieved to optimize radiant energy absorption.
Session 29D, Food Engineering: Thermal processes
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