Water absorption in dried beans

Department of Materials Science and Engineering, National Tsing Hua University, Hsin-chu-hsien, Taiwan, Taiwan
Journal of the Science of Food and Agriculture (Impact Factor: 1.71). 04/2005; 85(6):1001 - 1008. DOI: 10.1002/jsfa.2058


Water absorption in dried beans has been investigated. Diffusion equations based on wetting theory are proposed and an analytical solution was obtained using Duhamel's theorem. The green bean, red bean, California small white bean and soybean are considered. Some green beans and red beans were irradiated by gamma-rays. The theoretical predictions are in excellent agreement with the experimental data. The diffusion coefficients of water in green bean and red bean satisfy the Arrhenius equation. The testa wetting was analyzed on a thermodynamic basis. The wetting time of water molecules from water reservoir to embryo of green bean and red bean via testa was found to satisfy a modified Arrhenius equation. The activation energy of diffusion is greater for non-irradiated red bean than for irradiated red bean, but the energy barrier of wetting is smaller for non-irradiated red bean than for irradiated red bean. However, the effects of gamma-rays on diffusion and wetting in green bean are not pronounced. The time to cook the green bean until well done was analyzed and the effect of water uptake on cooking time is discussed. The water transport in hulled green bean was also investigated. The wetting behavior was not observed in the hulled green bean. This is direct evidence of the wetting behavior of the testa. The water uptake in the hulled green bean is greater than that in the coated green bean. Copyright © 2005 Society of Chemical Industry

  • Source
    • "The wetting time follows the wetting theory and the modified Arrhenius equation (Liu et al., 2005) which are described in the Supplementary Material: A1. Wetting theory of Epidermis. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Chlorophyll has long been considered to have health benefits and is widely used as a food additive. The conventional extraction method using organic solvents involves penetration and diffusion through many layers of a leaf structure, making it hard to predict and control. A diffusion equation with boundary conditions based on the wetting theory was proposed. Three kinds of solvent–acetone ethanol, and dimethyl sulfoxide – were used to extract chlorophyll from creeping oxalis. Chlorophyll of three kinds of plants (creeping oxalis, nodalflower synedrella, and broomjute sida) were extracted by 80% acetone. The amounts of extracted chlorophyll were in good agreement with the theoretical prediction. The effective diffusion coefficient of the chlorophyll transport increases with increasing energy barrier of chlorophyll wetting at the epidermis for all solvent types, acetone concentrations, and plant species. The barrier height of chlorophyll wetting increases with surface energy of plants.
    Full-text · Article · May 2014 · Journal of Food Engineering
  • [Show abstract] [Hide abstract]
    ABSTRACT: This work provides a novel view of explaining water uptake behavior commonly observed in legume seeds. A model proposed by Peleg to describe the mechanical changes in biomaterials transitioning from a glassy state to a rubbery state was used to describe water uptake by legume seeds exhibiting a lag during imbibition and to characterize the mechanical changes of the seed coat as affected by soaking time. The seeds characterized by Peleg's model possessed seed coats with a glass transition temperature higher than ambient soaking conditions. Alternatively, the water uptake behavior of legume seeds that did not exhibit a lag phase was characterized by an exponential equation used in polymer science to model solvent sorption by materials above their glass transition. A modified exponential equation was developed to model the mechanical behavior of these seed coats as affected by soaking time. Seeds characterized by the exponential equation possessed seed coats with a glass transition temperature near ambient soaking conditions. This work demonstrates, through the use of two separate models, water uptake behavior of legume seeds can be explained by the glass transition temperature of the seed coat.
    No preview · Article · Jan 2010 · International Journal of Food Engineering
  • Source

    Full-text · Article · Jan 2011
Show more