Simple method for the selection of the appropriate food simulant for the evaluation of a specific food/packaging interaction

Knowledge of the extent of food/packaging interactions is essential to provide assurance of food quality and shelf life, especially in migration and sorption processes that commonly reach equilibrium during the lifetime of a commercial packaged foodstuff. The limits of sorption and migration must be measured in the presence of the specific food or an appropriate food simulant. The partition equilibrium of food aroma compounds between plastic films and foods or food simulants (K K,P/L) has been characterized. Two polymers (LLDPE and PET), three organic compounds (ethyl caproate, hexanal and 2-phenylethanol), four food products with varying fat content (milk cream, mayonnaise, margarine and oil) and three simulants (ethanol 95%, n -heptane and isooctane) were selected for study. The results show the effect of the aroma compound volatility and polarity, as well as its compatibility with the polymer and the food or food simulant. Equilibrium constants for the organic compound between the polymers and a gaseous phase (K A,P/V) as well as between the food (or food simulant) and a gaseous phase (K A,L/V) were also determined. An approach is presented to estimate K from the binary equilibrium constants K A,P/L and K A,P/L. Calculated results were shown to describe experimental data very well and indicated that compatibility between the aroma and the food or food simulant is the main contributing factor to the partition equilibrium describing the extent of food/packaging interactions. Therefore, the measurement of liquid/vapour equilibrium can be regarded as a powerful tool to compare the effectiveness of food simulants as substitutes of a particular food product and can be used as a guide for the selection of the appropriate simulant.