Mathematical modelling of chemical migration from food contact materials

Mathematical modelling of chemical migration from food contact materials 

Interaction between packaging and food consists of the transfer of substances from the environment as well as from the packaging into the food and vice versa. Chemical reactions inside the packaging or food are also possible. Not only can the quality of the packed food change due to such interactions, but the properties of the packaging may change as well, leading to further loss 

Mixing by convection in viscous and solid packed products have very little or no practical significance. A special case is the mixing of particulate products by shaking, which gives results similar to convection. The most 

In addition to mass and energy, other quantities can also experience transfer. Flowing layers with different flow rates in a convection stream can influence one another. The slower flowing layer acts as a brake on the faster layer, while at the same time the faster layer acts to accelerate the slower one. The cause of this behaviour is the iimer friction of the liquid appearing as a viscosity difference, which is a consequence of the attractive forces between the molecules. Viscosity can be explained as the transport of momentum. The viscosity of different media can be very different and thus plays an important role in transport processes. 

For the mathematical description and understanding of transport processes, it is advantageous for their descriptions to have several common characteristics, regardless of the nature of the transport quantity, to allow them to be treated in a similar manner. Without knowledge of their fundamental causes at the molecular level, which corresponds to their historical development, transport processes can be described with help from quantities that can be quantitatively measured on a macroscopic level. One such quantity is that of flux. 

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