17G-5 |
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O. SIPAHIOGLU, Department of Food Sciences, United Arab Emirates University, Al Maqam Campus, Department of Food Sytems, P.O.Box 17555, Al Ain, United Arab Emirates, C. Bircan, Department of Food Science, Adnan Menderes University, Gida Bilimi Bolumu, Ziraat Fakultesi, Aydin, Turkey, and S. A. Barringer, Dept. of Food Science & Technology, Ohio State Univ., 2015 Fyffe Ct., 317 Parker Food Science Bldg., Columbus, OH 43210-1007. Dielectric properties of a food, together with its thermal properties determine how efficiently it can be heated in a microwave oven. Dielectric constant is a measure of the ability of a material to store electromagnetic radiation. Dielectric loss factor is a measure of the ability of a material to dissipate electrical energy into heat. Dielectric properties are effected by food composition (mainly moisture and ash content), temperature and frequency of the microwave energy. Dates are the major agricultural commodity in the Gulf countries. Currently, there is a growing interest in using microwaves for processing dates. Date paste and syrup are the major products manufactured from dates. The objectives are determining the temperature and composition dependence of the dielectric properties of date paste and syrup, and developing equations as a function of temperature, moisture and ash content. Dielectric constant and dielectric loss factor of date paste and syrup with varying moisture and ash contents were measured from 20 to 100C using a network analyzer from 915 to 2450MHz. Dielectric constant of date paste and syrup increased with moisture content and decreased with ash content. Dielectric constant increased with temperature. Dielectric loss factor increased with moisture and ash content. Dielectric loss factor increased with temperature. Modeling date paste and syrup separately increased accuracy of the predictive equations for both dielectric constant and dielectric loss factor. The equations can be used for calculating energy absorption by date products with different moisture and ash contents at varying temperatures.
Session 17G, Food Engineering: Physical, chemical and electrical properties
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