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2004
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April
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In the Laboratory
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Kinetics of the Osmotic Hydration of Chickpeas
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Gabriel Pinto
Departmento de Ingeniería Química Industrial y del Medio Ambiente, E.T.S.I. Industriales, Universidad Politécnica de Madrid, 28006 Madrid, Spain
Ali Esin
Department of Food Engineering, Middle East Technical University, Ankara 06531, Turkey
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April 2004
Vol. 81 No. 4
p. 532
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| Abstract |
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An experiment examining the swelling of chickpeas as they are soaked in water is presented to introduce students to topics such as osmotic flow, mass transfer, diffusion, kinetics of hydration, modeling, and estimation of activation energy. The experiment may be performed by students at home, at the laboratory, or directly by the professor. Experimental data are analyzed using an empirical model (Peleg equation) for the description of moisture sorption curves for different foods soaked in water. The proposed experiment needs inexpensive hardware. The equations that fit adequately with experimental data allow the calculation of initial hydration rates at different temperatures, and subsequently, the estimation of the activation energy, Ea, of the process. The obtained value of Ea (19.5 ± 0.9 kJ/mol) shows a process controlled by diffusion and not by chemical reaction. It was also observed that, for a given temperature, the increase in concentration of NaCl in the immersion solution results in the decrease of hydration kinetics.
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| More Information |
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Citation |
Pinto, Gabriel; Esin, Ali. J. Chem. Educ. 2004 81 532.
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Keywords |
Diffusion; Distance Learning; Food Science; General Chemistry; Introductory / High School Chemistry; Kinetics; Laboratory Instruction; Physical Chemistry; Water / Water Chemistry
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History |
Created:
Last Updated: |
3/3/2004
2/2/2007
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| Home > JCE Print > Journal of Chemical Education > Issues >
2004
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April
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532
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