Influence of pasteurization and high pressure processing on the antioxidant activity of filtered and unfiltered lager beer

The aim of this study was to assess the impact of various final stabilization methods on the antioxidant activity of filtered and unfiltered lager beers, as well as to evaluate further changes during storage at various temperatures. Beers were processed by thermal pasteurization and by high pressure processing. The antioxidant activity was measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and by ferric ion reducing antioxidant power (FRAP) assay. The concentration of total polyphenols was also evaluated. Changes observed in the antioxidant activity during the storage period of 8 weeks were not associated with the type of the applied stabilization method. Increased storage temperature had negative impact on the antioxidant activity. Filtered beers exhibited lower values of antioxidant activity and lower concentration of total polyphenols in comparison to unfiltered samples. The results indicate that both thermal pasteurization and high pressure processing can preserve oxidative stability of beer and are, therefore, applicable methods for its shelf-life extension.