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Dual Mode Diffusion of NaCl in Japanese Radish under Cooking Conditions
Author(s) -
Hashiba H.,
Komiyama J.,
Nakanishi T.,
Gocho H.
Publication year - 2007
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2007.00304.x
Subject(s) - sorption , diffusion , chemistry , adsorption , thermodynamics , langmuir adsorption model , pectin , langmuir , partition coefficient , freundlich equation , analytical chemistry (journal) , chromatography , physics , biochemistry
Sorption and diffusion of NaCl in Japanese radish have been studied. The sorption isotherm was obtained at 98 °C by the conventional method. The concentration profile by the 1‐dimensional diffusion of NaCl in Japanese radish from the 3.0% solution was measured at 98 °C with the FRITRUC method involving a foodstuff rod in a thin rubber casing. Fick's diffusion coefficient, D , calculated therefrom showed a threefold variation with a maximum. This variation was quantitatively interpreted by applying a dual‐mode sorption and diffusion theory under an assumption that the rate determining step of the diffusion is that in the cell wall. Two thermodynamic diffusion coefficients, D T ( p ) and D T ( L ), where p and L are the species of NaCl sorbed by partition and Langmuir modes, respectively, a parameter, α, derived from the local equilibrium relations between the p and L species, and S , the concentration of the Langmuir adsorption site in the cell wall of the radish, were estimated. D T ( p ) was found to be smaller than D T ( L ). As an explanation of the larger D T ( L ), we invoked the higher hydration state of the adsorption site of the L species, being ascribed to residual anionic pectin in the radish than the local environment of the p species. The sorption isotherm showed a convex upward deviation from the linear relation. By using the parameters for the local equilibrium and some assumed parameters, the isotherm was found to be explainable. We suggest possible applications of the present method and interpretation to the diffusion study on the cooking systems comprising varieties of seasoning components and foodstuffs.