Modeling of the water absorption during the steeping of yellow peas

• A mechanistic model coupling mass transfer and mechanical deformation was developed.
• The model was validated for steeping of yellow peas at five temperatures.
• The model was more accurate than empiric or simplified mechanistic models.
• The surface resistance to mass transfer most affected the model predictions.

The aim of this work was to develop a model of the water uptake by yellow peas during the steeping step of a malting process to serve for the selection of most appropriate time–temperature conditions. Two empirical (Peleg and lag phase equations) and three mechanistic models (Fick law analytical solution with and without consideration of the surface resistance to mass transfer and a comprehensive model coupling mass transfer and mechanical deformation) were developed. The coupled mass transfer and mechanical deformation model (RMSE = 0.025, R2 = 0.98), the Peleg equation (RMSE = 0.025, R2 = 0.97) and Fick law analytical solution with consideration of the surface resistance to mass transfer (RMSE = 0.026, R2 = 0.97) provided the best description of the water uptake of peas measured at five temperatures. The coupled mass transfer and mechanical deformation model provided accurate estimate of the volume of peas at saturation. A sensitivity analysis indicated that the mechanical deformation has negligible effect on the water absorption while the most important model components for appropriate estimation of the water content of peas during steeping were the rate constant for the Peleg equation and the surface mass transfer coefficient for the mechanistic models.