ANALYSIS OF SUPERCRITICAL CARBON-DIOXIDE EXTRACTS FROM CONES AND LEAVES OF A HUMULUS-LUPULUS L CULTIVAR

Extracts obtained by supercritical carbon dioxide extraction of cones and leaves of hop (Humulus lupulus L) at different combinations of temperature and pressure were analysed for their alpha- and beta-acids and volatiles, using HPLC and GC respectively. The yield and composition of the mixtures of bitter compounds from the cones were largely influenced by the temperature and pressure applied during the extraction. Bitter compounds could not be detected in the extracts from the leaves. The most important volatile components identified were beta-myrcene, beta-caryophyllene and alpha-humulene. The extraction parameters also influenced the composition of the mixture of volatiles from the cones and leaves, 40-degrees-C and 20.0 MPa being optimum for the extraction of both bitter compounds and volatiles, which are thought to be important for the aroma of beer.