Evaluation of Antioxidant Activity on Flavor Stability of Beer and Beer-Like Beverages

Abstract

The relationships among flavor stability, antioxidant activity, and aging-related indices of beer were examined in traditional all-malt and adjunct beer, Happoshu (a beer-like beverage with less than 67% malt content), and New-genre (a beer-like beverage without malt, or Happoshu diluted with spirit) beverages. Flavor stability was evaluated by assessing flavor-staling degree using sensory analysis after an accelerated storage test at 30°C. Hydroxyl radical, the most reactive oxygen species, is considered a major determinant for flavor stability of beer. However, the staling degree measure exhibited a more significant correlation with 1,1′-diphenyl-2-picrylhydrazyl (DPPH)-scavenging activity than the hydroxyl radical-scavenging activity. The lag time of the hydroxyl radical generation analyzed by electron spin resonance spectroscopy is now used as an index of flavor stability of beer; it is thought that longer lag times indicate higher antioxidant activity of beer. However, a markedly longer lag time was observed in Happoshu and New-genre than in beer, although Happoshu and New-genre showed lower antioxidant activities than beer. Lag time did not appear to be applicable as an index of flavor stability for Happoshu and New-genre. DPPH-scavenging activity was found to be a more suitable and a common index for assessing flavor stability in not only traditional all-malt and adjunct beers but also Happoshu and New-genre, depending mostly on polyphenol-mediated antioxidant activity. In a brewing fermentation test, changes in DPPH-scavenging activity during fermentation were not observed, which suggests that the antioxidant activity of casting wort could be critical to the flavor stability of not only beer but also beer-like beverages.