ISHS Acta Horticulturae 668: I International Humulus Symposium
CONTENTS OF PRENYLFLAVONOIDS IN CZECH HOPS AND BEERS |
| Authors: | K. Krofta, J. Poustka, K. Nováková, J. Hajšlová |
| Keywords: | hops, Humulus lupulus, prenylflavonoids, xanthohumol, bitter acids, beer brands, isoxanthohumol, liquid chromatography |
| Abstract:
The contents of prenylflavonoids (xanthohumol, desmethylxanthohumol, isoxantho-humol) were investigated in all Czech hop culůtivars during the period 2000-2003. The concentrations of xanthohumol varried between 0.2 and 1.1% (w/w) with the highest amounts found in the new Czech high-alpha hop cultivar, Agnus. The highest ratio of xanthohumol/alpha acids, greater than 10-1, was determined for Sladek. A positive correlation was observed for the xanthohumol and alpha acids. Fresh hops contain also small amount of isoxanthohumol (up to 2.10-2 %(w/w). Desmethylxanthohumol was present in Czech hop cultivars in the range of 0.50 to 0.20% (w/w). The contents of prenylflavonoids, predominantly isoxanthohumol, in Czech beers were usually between 0.3 and 1.9 mgL-1. Low isoxanthohumol levels were found if hop CO2 extracts were used. While prenylflavonoids were very minor constitients in draught or diet beers. Losses of isoxanthohumol on beer production were highest during wort cooling and trub removal. | |
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