LC-MS/MS Analysis of Hop Flavonoids in Dry-Hopped Beers

Abstract

As a major ingredient during beer brewing, hops give a characteristic bitter taste to the final product. The quantitative analysis as well as the knowledge of the contribution of hop bitter compounds to the overall bitter taste of beer is therefore essential. HPLC-UV analysis of selected bitter substances like alpha-acids or humulinones (oxidized alpha-acids) in dry-hopped beers is feasible. Reliable structure identification and quantification of hop flavonoids like multifidol, kaempferol and quercetin glycosides require the use of HPLC-MS/MS technique. New findings about key bitter compounds from hops (e.g. co-multifidol glucoside) and their contribution to the bitter profile of beer were introduced and discussed in literature recently. To monitor selected hop flavonoids in dry-hopped beers, an in-house HPLC-MS/MS method was developed. Dry-hopped beers produced with different hop varieties showed significant differences in their hop flavonoids pattern.