Migration study of carvacrol as a natural antioxidant in high-density polyethylene for active packaging

Abstract

The migration behaviour of low molecular weight compounds from food packaging materials is one of the key issues in assessing the possibility of use in such applications. The aim of this work was to study the migration of carvacrol (1% and 2% w/w) when added to high-density polyethylene. All materials were exposed to the food simulants olive oil and distilled water separately at 40°C and 25°C. Three significant variables influencing the migration process were considered: incubation temperatures, the initial concentration of antioxidant, and the type of simulant (oil and aqueous). The amount of carvacrol migrating to olive oil was significantly higher than in water because of the higher solubility of this antioxidant in oil. Experimental results agreed reasonably well with those obtained by the application of a simple model derived from Fick's Second Law. Carvacrol could therefore be used in active packaging formulations as its release from the polymer matrix can be controlled.

Keywords:

• migration
• active packaging
• carvacrol
• high-density polyethylene

Acknowledgements

The authors wish to thank the Department of Civil and Environmental Engineering, University of Perugia in Terni (Professor José M. Kenny and Dr Antonio Iannoni), the Department of Materials Science and Engineering (Polytechnic University of Valencia) for their support in the samples preparation and testing, and Dr M. Carmen Garrigós for useful discussion and the University of Alicante (SICyT UAUSTI08-04) for financial support. In addition, the authors thank Repsol-YPF for supplying the material. Mercedes Peltzer was granted by Alban Programme (European Union) (Grant Number E04D031633AR).