ABSTRACT The aim of this work is to improve the knowledge concerning moisture mobility in gelatin slabs, through the evaluation of moisture diffusivity (function of temperature and moisture content) by modeling of drying kinetics The first part of this work is devoted to the determination of the gel characteristics needed for a good modeling. Drying experiments were then carried out on a pilot drier according to a central composite design with 3 factors (temperature, moisture content and pH). Moisture diffusivity was finally calculated by fitting a model to the drying experiments. The chosea model (a conventional diffusive model with variable diffusion coefficient, solved by finite difference calculations in a solid-related frame of coordinates) did not perfectly fit the experimental results. It especially under-estimates moisture gradients at the surface of the gel
[1]
J. Crank,et al.
An evaluation of the diffusion coefficient for chloroform in polystyrene from simple absorption experiments
,
1949
.
[2]
Vaios T. Karathanos,et al.
Comparison of Two Methods of Estimation of the Effective Moisture Diffusivity from Drying Data
,
1990
.
[3]
C. Michon,et al.
Concentration dependence of the critical viscoelastic properties of gelatin at the gel point
,
1993
.
[4]
Z. Maroulis,et al.
Moisture Diffusivity Data Compilation in Foodstuffs
,
1996
.
[5]
K. Nijenhuis.
Investigation into the ageing process in gels of gelatin/water systems by the measurement of their dynamic moduli
,
1981
.
[6]
A. Lebert,et al.
The drying kinetics of mint (Mentha spicata Huds.)
,
1992
.