Dynamics of Solidification in 2% Corn Starch-Water Mixtures: Effect of Variations in Freezing Rate on Product Homogeneity |
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| Authors: | STEPHEN J MASHL ROLANDO A FLORES ROHIT TRIVEDI |
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| Affiliation: | Author Mashl is with Ames Laboratory, US-DOE, at Iowa State University. Author Flores is with the Dept. of Agricultural &Biosystems Engineering and the Dept. of Food Science &Human Nutrition, 1535 Food Sciences Bldg., Iowa State University, Ames, IA 50011. Author Trivedi is with the Dept. of Materials Science &Engineering and Ames Laboratory, US-DOE, Iowa State Univ., Ames, IA 50011. Direct inquiries to Dr. R.A. Flores. |
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| Abstract: | Directional solidification studies of gelatinized corn starch-water mixtures were undertaken in order to examine, in situ, the freezing behavior of this food model. The solidification rate was controlled by varying sample cell velocity as it moved from a 25°C hot stage to a -25°C cold stage. While freezing at cell velocities ≤7.5 μm/sec, starch granules were alternately pushed or entrapped by the advancing solid-liquid interface producing a segregated structure consisting of alternating high-starch and low-starch bands. At a cell velocity of 10 μm/sec, the frozen product was homogeneous. The relationship between the solid-liquid interface velocity and segregation behavior was quantified and compared to an existing model of particle-interface interactions. |
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| Keywords: | solidification dynamics corn starch freezing rate product homogeneity directional solidification |
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