Analysis of diffusion of L-glutamic acid, sodium ions and D-glucose in agar gel containing xanthan gum

We studied the diffusion processes of seasoning materials (l-glutamic acid, sodium ion and d-glucose) in gels. In the present study, the gel was soaked in a solution containing 0.30%(W/V) monosodium glutamate, 1.0% (W/V) NaCl and/or 3.0%(W/ V) d-glucose, and the apparent diffusion coefficient (D) was determined in 2.0% (W/ W) agar gel containing xanthan gum ( 0 %, 0.20% or 0.50% (W/W)) after 24 hr at 30 °C in a one-dimensional diffusion system. As the results, the D of l-glutamic acid increased in the presence of NaCl in the agar gel containing xanthan gum, but the increasing effect disappeared by the further addition of d-glucose. The increase in D of sodium ion by the addition of xanthan gum was also suppressed by the addition of d-glucose. It was obvious that the dif fusion of sodium ions was facilitated by the carboxyl-group in the xanthan gum, and that the diffusion of l-glutamate increased with the flow of the sodium ions.