Use of optical oxygen sensors to monitor residual oxygen in pre- and post-pasteurised bottled beer and its effect on sensory attributes and product acceptability during simulated commercial storage

Disposable optical oxygen sensors were used to non-destructively assess the levels of residual oxygen in the headspace of commercially produced Lager beer in 330 ml clear glass bottles. Monitored before and after pasteurisation, oxygen concentration was observed to drop as oxygen diffused into the beer. Oxygen levels between 0% and 5% were present in the bottle headspace pre-pasteurisation. Oxygen diffusion into the beer was monitored over time under refrigeration (∼4 °C) and a sensory panel was used to determine the effect of residual oxygen on the sensory quality of the beer. The headspace in the bottles was also monitored over time where oxygen increased to a level of ∼0.5% on average over the course of the shelf life. Interestingly, results showed that beer samples possessing higher levels of oxygen present prior to pasteurisation also possessed the most negative sensory attributes associated with the beer, particularly those consistent with beer staling. The developed optical sensor was shown to act as a predictor of sensory quality and may have on-line applications in the beer packaging sector.

► Disposable optical oxygen sensors were used to assess the levels of residual oxygen in the headspace of Lager beer. ► Oxygen diffusion into the beer was monitored. ► A sensory panel was used to determine the effect of residual oxygen on the sensory quality of the beer. ► Beers possessing high initial oxygen prior to pasteurisation were the most negative for sensory derived beer staling. ► The sensor acted as a predictor of sensory quality for on-line applications.