PETpla.net Insider 09 / 2020

INSPECTION 48 PETplanet Insider Vol. 21 No. 09/20 www.petpla.net Ensuring bottled beverage shelf-life Oxygen transmission rate testing by Michelle Stevens, technical expert in the barrier packaging industry, Systech Illinois, brand of Industrial Physics As the beverage industry experiences increased focus on health and wellness products, demand for oxygen transmission rate measurement of bottles has compounded. Many of the new products are diverging from traditional carbonated soft drink recipes to include fruit juices, vitamins, minerals, and other oxygen sensitive ingredients. Traditional methods for deter- mining a bottle’s shelf-life are no longer adequate, if even relevant. O 2 ingress resulting in ingredient deficiency, rancidity and/or off-fla- vours is quickly becoming the limiting factor in beverage bottle shelf-life. Oxygen transmission rate (OTR) testing of the entire bottle as well as the components is now required in both research and development and quality assurance / quality control scenarios. Oxygen transmission greatly influences the shelf-life of a bever- age as the ingress of oxygen can rob the product of flavour, colour, taste, and nutrition. Oxygen can also cause adverse reactions in oxygen-sensitive ingredients found in many health and wellness beverages. By measuring the rate at which O 2 transmits through the package material, one can begin to determine the shelf-life or amount of time the unopened package will still provide ‘good’ product. Oxygen transmission rate testing for R&D and component testing Oxygen transmission rate testing is crucial in both the bottle design/R&D phase as well as QA/QC phase. Bottles are tested for OTR by challenging the outside of the bottle with oxygen (typi- cally either 21% [room air] or 100%) and sweeping the inside with a nitrogen carrier gas. Molecules of O 2 that perme- ate the bottle are picked up by the N 2 carrier gas and analysed at a detector. The concentration of O 2 at the sensor is translated to an OTR with typical units of cc/day, which corresponds to the amount of oxygen entering the entire bottle in one day. From bottle design to QA/QC, a variety of OTR testing variations may be used. In the development phase, mate- rials are tested as flat films. Based on OTR performance and a host of other factors, top-ranking candidate materials are formed into bottles. It is crucial to test the OTR of each candidate again as a bottle because processing condi- tions, thickness variations and other factors can alter the predicted OTR value of the finished product. Because oxygen ingress is not limited to just the bottle, the closure system must also be evaluated for OTR. Finally, the entire bottle and closure system can be tested as a complete, finished package.