The development of a clear monolayer polyethylene terephthalate (PET) with an oxygen-scavenging barrier could be the impetus companies need in deciding whether to make the conversion to plastic containers from glass or metal.

While PET is one of the fastest growing sectors of the beverage bottling market, taking over from glass and cans as the container of choice, its use has been mainly limited to fizzy drinks and water. PET has the practical benefit of being lightweight, shatterproof and recloseable. It is also completely recyclable, giving it an edge under the EU's new regulations on reducing packaging waste.

However PET, and plastic in general, is not very good at keeping oxygen from permeating the container and reducing the shelf life of such products as juices, teas and flavoured water. Oxygen has a degrading effect on flavour, colour and vitamin content for many beverages. Now Philadelphia-based Constar International says it has developed a material that when blended with monolayer PET, binds oxygen, thus preventing the degradation of products such as juices, teas and flavoured water.

The product, called DiamondClear, is currently being tested before being submitted for regulatory approval. Oxygen "scavengers" minimise the permeation of oxygen through the container by chemically binding the molecules. Paul Prinko, Constar's marketing manager, told FoodProductionDaily.com that the company's DiamondClear represents a breakthrough in PET oxygen scavenging technology by offering both the clarity of glass and an economical monolayer structure.

"The economics of the DiamondClear monolayer solution is superior to other barrier methods," he said in an interview. Constar is among a number of container manufacturers who have been searching for a solution to PET's oxygen problem.