Effect of relative humidity on the migration of benzophenone from paperboard into the food simulant Tenax® and modelling hereof
The aim of this study was to investigate the effect of relative humidity on the migration of benzophenone from paperboard into the food simulant Tenax®. Kinetic migration investigations were carried out with three relative humidities in the interval between 39% and >73%. All investigations were carried out at a constant temperature of 34°C. It was found that the migration of benzophenone after more than 30 days was 4.8 times higher at a relative humidity of 64%–71%, and 7.3 times higher at a relative humidity of >73%, compared with that at a relative humidity of 39%–49%. Diffusion and partition coefficients were derived from the results by using a software for modelling migration in multilayer materials. Both the diffusion coefficient and the partition coefficient, between paperboard and Tenax®, decrease with increasing relative humidity. The experimental results were correctly modelled only when the paperboard was regarded as a one-layer system as compared with a two-layer system: where the main part of the paperboard (B1) has a high diffusion rate and a thin part of the paperboard (B2) in contact with the foodstuff has a lower diffusion rate.
Investigation of Migration Model of Printing Inks on Paper Packaging
The printed packaging was divided into ink layer and paper layer. The migration model was developed based on penetration and Fick's second law. hm and KF,P at the interface of the paper and the food were considered in the model. After the penetration of the ink, the distribution of the contaminant in the paper layer was discrepant for paper with different thickness. The model could be simplified to be single-layer or two-layer packaging model in special cases. Three special cases of the model were validated: (1) special case 1 of the model was a single-layer model just considering hm at the interface. This special model was compared with the classical model; (2) special case 2 of the model was also a single-layer model validated by experimental data in reference; and (3) special case 3 was the two-layer model validated by experimental data in reference. The model was proven to be effective by above validation. 
 
 
 
Practical Applications 
 
The use of migration models to evaluate the safety of plastic food packaging is economical and time-saving compared with the experiments. As the second important packaging material, paper packaging is widely used for its environmental friendliness. However, up until now, there is no general migration model of paper packaging. A migration model of the contaminants from the inks on paper packaging was developed to predict them in different packaged food under certain migration conditions. Diffusion, partition and mass transfer coefficients were introduced to the model for better prediction. The simplified model can be used for other packaging materials and single or multilayer packaging. This model can help to design packages with acceptable migration of the contaminants.
Iustitia Dei: A History of the Christian Doctrine of Justification
Preface Acknowledgements 1. Prolegomena 2. The fountainhead: Augustine of Hippo 3. The development of the doctrine in the medieval period 4. The medieval schools of thought on justification 5. The transition from the medieval to the modern period 6. The development of the doctrine in the Reformation period 7. The Tridentine decree of justification 8. The legacy of the English Reformation 9. The modern period Appendix: a glossary of medieval soteriological terms Abbreviations Notes Bibliography Index.