Publication Date: 2011-Sep-08
The IP.com Prior Art Database
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This invention relates to scavenging oxygen and particularly, although not exclusively, relates to the scavenging of oxygen in containers, for example food or beverage containers.
WO2008/090354A describes a container comprising a hydrogen generating means for generating molecular hydrogen in a chemical reaction involving an active substance incorporated in the container. A catalyst is associated with the container for catalyzing a reaction between the molecular hydrogen and molecular oxygen which enters the container, thereby to scavenge the oxygen and protect the contents of the container against degradation
due to and/or associated with the presence of oxygen. Thus, the shelf life of foods and beverages packaged in plastics, for example polyethylene terephthalate containers, can be extended. The specific examples in WO2008/090354A demonstrate the efficacy of the invention, with reference to PET bottles blown from a mixture of PET and palladium catalyst so the catalyst is distributed throughout the bottle wall. Hydrogen is produced from plaques
containing sodium borohydride. The bottles are filled with tap water. Results show that there is no measurable increase in oxygen concentration over a test period of two months (Example 12).
WO2010/115992 also relates to the scavenging of oxygen in containers. In this case, a
wide range of closures for containers are described. No data is presented on the efficacy of the various closure designs described.
Whilst scavenging oxygen from containers containing foods or beverages which are not very oxygen sensitive is challenging, scavenging oxygen sufficiently quickly from containers
which contain very oxygen sensitive consumables (e.g. wine or fruit juices) is even more challenging - oxygen must be scavenged and/or reacted away at a rate which is quicker than the rate of reaction of oxygen with the consumable.
Juices contain vitamin C (ascorbic acid) which is very sensitive to oxygen and to extend
the shelf life (before and after initial opening) of packaged juice requires rapid scavenging of oxygen.
Figure 1 is a schematic representation of a juice bottle incorporating oxygen scavenging technology of the type described in WO2008/090354A and WO2010/115992A. The bottle 2
includes a closure 4 and body 6 containing juice 8 which contains ascorbic acid. The closure 4 incorporates a hydride which generates hydrogen on contact with moisture which fills headspace 9 and the body 6 comprises PET incorporating palladium catalyst. As illustrated, oxygen (O2) permeates the body 6 and hydrogen is generated in the closure. The hydrogen
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enters the headspace and some dissolves in the juice, which result in hydrogen permeating throughout the entire body 6, whereupon the hydrogen associates with the palladium catalyst, thereby to activate the catalyst. When oxygen permeates the body 6, at any point, it is then close to hydrogen activated catalyst, result...