Evolution of aroma compounds from orange juice stored in polyethylene terephthalate (PET)

Abstract

The evolution of aroma compounds from orange juice made from concentrate and stored in glass, standard monolayer polyethylene terephthalate (PET 1), multilayer PET (PET 2) and plasma-treated PET (internal carbon coating) (PET 3) was investigated. Bottles were stored at room temperature (20°C) under artificial light. Volatile compounds in orange juice samples and corresponding packaging materials were analysed at zero time and after 2, 3 and 5 months of storage. After 5 months of storage, from 0.2 to 0.3% of the initial amounts of limonene and β-myrcene in the orange juice had been absorbed by the plastic packaging materials. Statistical analyses showed that the evolution of aroma compounds was strongly correlated to the duration of storage, but not to the type of packaging material. Indeed, whatever the stored orange juice samples, the same evolutions were observed, with a decrease in aldehydes and ketones, esters, aliphatic alcohols, sesquiterpene and monoterpene alcohols, and an increase in two aliphatic and monoterpene alcohols (i.e. furfural and 4-vinylguaicol). The results suggest that the losses of aroma compounds from the juice could be attributed to the high acidity of the matrix, implying acid-catalysed reactions. Finally, PET packaging materials and their corresponding oxygen permeabilities showed no correlation with the loss of aroma compounds.

Keywords:

• Orange juice
• polyethylene terephthalate (PET)
• glass
• volatile compounds
• packaging
• absorption

Acknowledgements

The authors thank Sidel (Octeville sur Mer, France) for the ACTIS Lite™ technology and for measuring the oxygen permeability of plastic materials; and Amcor for the Bindox® technology. Thanks also to the French Ministry of Research (CANAL-ARLE project) and to Délifruits (St-Donat sur l’Herbasse, France) for grants that supported this study. The authors also thank Tatiana Rodrigues Lima for technical support, and Perla Relkin for helpful advice and assistance in use of the DSC technique.