Exploration of the link between processing methods and product stability

摘要

The impact on flavour and foam stability of tunnel pasteurisation, flash pasteurisation and sterile filtration was investigated. The study found that consumers were unable to detect flavour differences between fresh samples of pasteurised and unpasteurised beer. Examination of staling over time with a professional taste panel showed that differences between pasteurised (tunnel, flash) and unpasteurised samples were detectable but small. In an additional study the impact of oxygen on pasteurised beers was examined. Results confirmed that low oxygen concentrations are important for flavour stability. The results also indicated that changes to oxygen concentrations above 0.3 ppm can be detected in increased perception of staleness. Below 0.3 ppm oxygen reductions in concentration could not be shown to offer a reduction in perception of stale. A foam stability study showed that pasteurised beer has more stable foam at the end of shelf life than unpasteurised samples. The difference may be explained by the activity of yeast derived proteases in unpasteurised beer.