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Modeling Starch Gelatinization Kinetics of Milled Rice Flour

March 2000 Volume 77 Number 2
Pages 145 — 147
Carlos A. Ojeda , 1 Marcela P. Tolaba , 1 and Constantino Suárez 1

Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, (1428) Buenos Aires, Argentina


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Accepted November 29, 1999.
ABSTRACT

Milled long-grain rice samples were evaluated by differential scanning calorimetry (DSC) to determine the kinetics of starch gelatinization. The experiments were conducted with milled rice flour with a 10.6% degree of milling. DSC thermograms were obtained from 35 to 110°C using heating rates between 1°C/min and 15°C/min. The rate constants were evaluated, and two activation energies were found for different temperature ranges. At <70.1°C gelatinization was not completed. It was assumed that at <70.1°C gelatinization would only affect the amorphous regions. During the subsequent phase the crystalline regions destabilized by the amorphous component begin to gelatinize. For moisture content of 70%, wet basis, and a heating rate of 12°C/min, the enthalpy of gelatinization reaches a constant value of 7.3 J/g.



© 2000 American Association of Cereal Chemists, Inc.