QUANTITATIVE-ANALYSIS OF PURINE NUCLEOSIDES AND FREE BASES IN WORT AND BEER

Low molecular mass compounds containing purine or indole groups exhibit adsorption-based retention characteristics when chromatographed on high performance size exclusion chromatography supports (Superose 12 and Superdex 75). Exploitation of this phenomenon enabled the development of a method for the quantitative analysis of purine nucleosides and free bases in wort and beer. Using this technique, a survey of 18 commercial beers showed the following range of variation of concentrations of these compounds :guanosine + deoxyguanosine 19-110 mg/L, adenosine + deoxyadenosine 3-43 mg/L, xanthine 1-41 mg/L, guanine < 1-11 mg/L and adenine < 1-7 mg/L. Analysis of wort and beer from a commercial brewery demonstrated a decline in both adenine and guanine and an increase in xanthine during the course of a typical fermentation.