Quantitation of Potential Flavoring Compounds in Worts and Beers by HPLC. Asaf A. Qureshi, W. C. Burger, and N. Prentice, USDA-SEA, Barley and Malt Laboratory, 501 N. Walnut Street, Madison, WI 53705, and Department of Agronomy, University of Wisconsin-Madison. J. Am. Soc. Brew. Chem. 37:0153, 1979.

Worts or beers sampled at five stages of brewing were quantitatively analyzed by high-performance liquid chromatography for purines, pyrimidines, nucleosides, nucleotides, polyphenols, and pyrazines. A commercial reverse-phase column to which clarified wort and degassed beer could be applied without prior treatment was used. Fifty-eight compounds were identified, and about 30 additional compounds were resolved. Sweet worts contained relatively low concentrations of nucleotides and pyrazines and higher concentrations of the nucleobases, nucleosides, and polyphenols. Boiling and hopping caused net decreases in total polyphenols. Fermentation increased the levels of uridine 5'-monophosphate (UMP), adenosine 2'-monophosphate (AMP), and 2'-UMP, and induced the formation of many pyrazines. The most abundant compounds in bottled beers were guanosine, cytidine 3'-monophosphate (CMP), 5'-AMP, 2'-UMP, methylpyrazine, catechin, and quercetin. Beers produced from Larker and blue-aleurone 6-rowed barleys had a quercetin to catechin ratio greater than one; beers produced from 2-rowed or Karl-type 6-rowed barleys had a quercetin to catechin ratio of one or less.

Keywords: Beer flavor, Nucleobases, Nucleosides, Nucleotides, Polyphenols, Pyrazines