Stability comparison of lager with dark and nonalcoholic beers using epr spin trapping technique

Abstract

The spin trapping technique test effectively used in the characterisation of the flavour stability of lager beers was applied to dark and non-alcoholic beers. The induction period for the formation of free radicals as indicated by spin trapping during thermally initiated staling is determined by antioxidants naturally occurring in beer, and its length is taken as a measure of the stability of the beer (lag time). This induction period is not evident in dark and non-alcoholic beers, suggesting lower stability as compared to lager beers, although ABTS•+ tests assigned a comparable antioxidant activity to the dark beers as was found for lager beers. A possible explanation for the missing induction period in the dark and non-alcoholic beers is the presence of more effective antioxidants in lager beers, able to rapidly terminate the initially-formed reactive free radicals. Caramel used in the production of dark beers showed relatively high scavenging activity of free radicals.