The Impact of a Xanthohumol-Enriched Hop Product on the Behavior of Xanthohumol and Isoxanthohumol in Pale and Dark Beers: A Pilot Scale Approach

Paulo J. Magalhães^1,4, Pavel Dostalek², José M. Cruz³, Luís F. Guido¹ and Aquiles A. Barros¹
¹ REQUIMTE – Departamento de Química da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal.
² Department of Fermentation Chemistry and Bioengineering, Institute of Chemical Technology, Technicka 5, 166 28 Prague, Czech Republic.
³ IBESA – Instituto de Bebidas e Saúde, Apartado 1044, 4466-955,S. Mamede de Infesta, Portugal.
⁴Corresponding author: E-mail: pauloxenon@gmail.com

J. Inst. Brew. 114(3), 246–256, 2008 | VIEW ARTICLE

ABSTRACT
Based on the health-promoting properties of xanthohumol (XN), the production of an enriched beer in this substance would be of interest to the brewing industry, from the perspective of pointing out the benefits that beer could bring consumer health. For that purpose, in this work efforts were applied to produce a beer enriched in XN. Also investigated was the influence of a XNenriched hop product on the content of XN and isoxanthohumol (IXN) in pale and dark beers. It was verified that XN was largely converted into IXN during wort boiling. However, the use of dark malts revealed a positive effect on the thermal isomerisation of XN. These results are indicative of the isomerisationinhibiting effect of the stout production process, which resulted in high levels of XN in the beer. Further losses of XN were due to incomplete extraction from the hops into the wort, adsorption to insoluble malt proteins and adsorption to yeast cells during fermentation. It was possible to produce a dark beer enriched in XN (3.5 mg/L) by using coloured malt (caramel malt, roasted malt and roasted malt extract) and a special XN hop extract combined with late hop usage during wort boiling.

Key words:
beer, health, hop, isoxanthohumol, polyphenols, xanthohumol.