Thermal Conductivity of Gelatinized Starches

Authors

  • Z.B. MAROULIS,

    1. The authors are with the Dept. of Food Science & Center for Advanced Food Technology, Rutgers Univ., New Brunswick, NJ 08903. Authors Maroulis and Saravacos are also affiliated with the Dept. of Chemical Engineering, National Technical Univ., GR-15773 Athens, Greece.
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  • K.K. SHAH,

    1. The authors are with the Dept. of Food Science & Center for Advanced Food Technology, Rutgers Univ., New Brunswick, NJ 08903. Authors Maroulis and Saravacos are also affiliated with the Dept. of Chemical Engineering, National Technical Univ., GR-15773 Athens, Greece.
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  • G.D. SARAVACOS

    1. The authors are with the Dept. of Food Science & Center for Advanced Food Technology, Rutgers Univ., New Brunswick, NJ 08903. Authors Maroulis and Saravacos are also affiliated with the Dept. of Chemical Engineering, National Technical Univ., GR-15773 Athens, Greece.
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  • Presented at the 50th Annual Meeting of the Institute of Food Technologists, Chicago, IL, June 25–29, 1989. New Jersey Agricultural Experiment Station publication No. D–10544–5–89, supported by State funds and the Center for Advanced Food Technology, Rutgers University. The Center for Advanced Food Technology is a New Jersey Commission on Science and Technology Center.

ABSTRACT

The thermal conductivity (k) of gelatinized high-amylose and high-amylopectin starches was determined, using the heated probe method. The granular starches, mixed with distilled water at 1 to 4 kg water/ kg dry solids, were gelatinized at 120°C. Similar k values which varied from 0.434 to 0.548 W/mK in the temperature range 30 to 70°C were obtained for both starch gels. Experimental data were fitted to six structural models, representing various geometries for mixtures of water and dry starch. The perpendicular model, based on heat conduction in series through layers of dry starch and water, yielded best correlations. The predicted thermal conductivity of dry gelatinized starch (ks) increased linearly with temperature T (K) according to the equation:

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