Analysis using effective two fick's diffusion coefficients for the diffusion profiles of NaCl and D-glucose in non-heated and heated food materials

Abstract

Mass transfer in food substrates is impor tant for understanding the cooking processes. In classical studies for the diffusion processes of seasoning materials in the substrates, it has been typical to assume a single Fick's diffusion coefficient D for the interpretation. In the present study, the concentration profiles of NaCl in konjac, sweet potato and apple, whether they were preheated or raw, were measured by soaking the materials in a solution for several periods 30-180 min at 85 . As the results of konjac 180 min and sweet potato raw and preheated, 30 min , the profiles were found to be successfully reproduced by assuming two D's under their changing contributions with the NaCl concentration. The diffusion behaviors of glucose in konjac and sweet potato were also studied. The concentration profile for konjac was well reproduced with a single D, but the profile for sweet potato preheated, 60 min needed to use the two coef ficients for the reproduction. The use of two D's also reasonably approximated the predictions by the dual mode diffusion theor y. It is expected that the present interpretation will provide a useful method leading to understanding the molecular processes involving the diffusion of small molecules in food substrates. ［論 文］