Hydration Kinetics of Red Kidney Beans (Phaseolus vulgaris L.)

Authors

  • NISSREEN ABU-GHANNAM,

    1. Author McKenna is affiliated with the Dept. of Food Science, University College Dublin, Belfield Dublin 4, Ireland. Author Abu-Ghannam's present address: Dublin Institute of Technology, Cathal Brugha Street, Dublin 1, Ireland.
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  • BRIAN McKENNA

    1. Author McKenna is affiliated with the Dept. of Food Science, University College Dublin, Belfield Dublin 4, Ireland. Author Abu-Ghannam's present address: Dublin Institute of Technology, Cathal Brugha Street, Dublin 1, Ireland.
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ABSTRACT

Soaking of dry red kidney beans was studied at 20, 30 40 and 60°C by the method of weight gain until equilibrium conditions were attained. Water absorbed during soaking was a function of both soaking time and temperature. Soaking at high temperatures increased the hydration rate constant and decreased soaking time to achieve equilibrium. Compared to unblanched beans, the application of a pre-blanching step considerably reduced hydration times of blanched beans. Due to the plasticity effect acquired upon blanching, blanched beans showed a significantly high hydration rate constant and exhibited a more constant equilibrium moisture content regardless of soaking temperature. Activation energy values (Ea) of the hydration process were 6.48 Kcal/mole for blanched and 14.25 for unblanched beans.

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