Simplified Mechanistic Models for Food Processes-Drying and Chromatography

Mechanistic modeling/simulation is quite important and useful for understanding, designing and operating various food processes. However, the rigorous mathematical/mechanistic models are complicated. It is also difficult and time-consuming to determine the parameter values needed for the simulation. Simplified mechanistic models are useful both for the process understanding and for the parameter value determination. In this paper, simplified mechanistic models for two food processes, drying of liquid foods and chromatography of proteins and food materials, are presented. Both of them are dif fusion-controlled processes. A short-cut method for determining the waterconcentration dependent dif fusion coefficient from isothermal drying rates is described. Factors affecting the drying rates and the inactivation of enzyme are explained based on the simplified model. For chromatography separation processes, a method for determining HETP from linear gradient elution (LGE) curves is explained. Then, how to tune separation performance in LGE is described based on the non-dimensional group (Yamamoto number). The productivity calculation methods based on the simplified model is also explained. The usefulness of a non-dimensional group for describing the dynamic binding capacity of the breakthrough curve for capture chromatography is also discussed.