Xanthohumol (XN), isoxanthohumol (IX) and 8-prenylnaringenin (8-PN) are important prenylflavonoids present in hops with potential beneficial properties. In this study, we examined differences in the content of XN, IX and 8-PN in hops and beer produced under organic and conventional production regimes. A An ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) method for analysing XN, IX and 8-PN in hops and beer was developed and validated, with LOQ ranging from 0.5 to 10 ng/mL. Finally, we examined 15N/14N and 12C/13C isotope ratios in the hops and beer using isotope ratio mass spectrometry (IRMS). The results show no statistically significant difference in the content of the selected prenylflavonoids between organic and conventionally produced hops and beer-in the whole sample group, as well as between the matched pairs. Stable isotope analysis indicated that only δ15N values are statistically higher in organically produced hops and beer. However, the differentiation according to the type of production could not be made solely based on the δ15N signature, but it could be used to provide supporting evidence.
Keywords: beer; hops; isotope ratio mass spectrometry (IRMS); liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS); organic; phytoestrogen; stable isotopes.