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Xanthohumol, a hop-derived flavonoid, has been linked to a number of positive health benefits, which has spurred an interest in the production of xanthohumol-enriched beers. The aim of the present study was to investigate the implications of xanthohumol enrichment on the oxidative stability of wort and beer. The levels of radicals in a model beer (5.8% ethanol, v/v) spiked with xanthohumol were evaluated by electron spin resonance. Xanthohumol exhibited radical scavenging properties at lower concentrations, reducing the formation of spin adducts by around 10% at 0.1 mg L–1. However, a trend toward radical formation was observed for concentrations higher than 5 mg L–1, indicative of a pro-oxidant effect. The influence of xanthohumol on the oxidative stability of the model beer was further determined by measuring the consumption of O2 in the presence of EBC worts made from different malts (pilsner, melano, and black). The addition of 10 mg L–1 of xanthohumol was also responsible for an increase of O2 uptake in the pilsner wort, whereas no effect was observed for black wort because of a possible interaction of xanthohumol with high-molecular-weight compounds generated during roasting. It has thus been demonstrated that xanthohumol-enriched pilsner beers could be prone to oxidation and, therefore, be less stable than xanthohumol-enriched beers brewed from dark malts. Keywords: Beer, Fenton reaction, Malt, Oxidative stability, Radicals, Xanthohumol
