Migration of model contaminants from PET bottles: influence of temperature, food simulant and functional barrier

Abstract

To simulate post-consumer recycled plastics, selected model contaminants were incorporated into PET bottles using a time saving method. Migration into 3% acetic acid, a cola-type beverage and 95% ethanol was followed during 1 year of storage at 20 and 40°C. Aroma compounds previously found in post-consumer PET material were used as model contaminants. Benzaldehyde was found to migrate to the highest extent. Storage at 40°C affected the bottle material and this might be one reason for the high migration values of these bottles. Migration into ethanol was up to 20 times higher than into 3% acetic acid or a cola-type beverage. Bottles with a functional barrier resisted migration into food simulants even when filled with 95% ethanol and stored for 1 year at 40°C. Differential scanning calorimetry measurements showed that ethanol was interacting with the plastic material. This resulted in a lower glass transition temperature of bottles stored with ethanol compared with bottles stored empty or with other food simulants.

Keywords:

• food packaging
• functional barrier
• migration
• model contaminants
• recycling plastics
• poly-(ethylene tetraphthalate) (PET)

Acknowledgements

AB Kulleborn & Stenström, Ullared, Sweden, is greatly acknowledged for its collaboration in the preparation of the bottles. Work was financially supported by the Swedish Council for Forestry and Agricultural Research (Project no. 50.0533/96).