Publication details, including instructions for authors and subscription information:

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 a-and /I-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 b-myrcene, /I-caryophyllene and a-humulene. The extraction parameters also influenced the composition of the mixture of volatiles from the cones and leaves, 40°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.

Capillary GC and GC-MS analysis of the essential oil from the cones of JUNIPERUS COMMUNIS L. grown wild in Greece showed a high content of alpha-pinene (ca 27%), sabinene (13%), germacrene-D (10%), and myrcene (9%). The total oil (yield 2.95%) consisted of almost 105 constituents, 77 of which representing 93.1% were identified. As the main component of the oxygenated monoterpenes was found the terpinen-4-ol (1.37%). Seasonal investigation of the essential oils showed mainly quantitative variations among the constituents.

Mature and immature fruits of a Cretan Vitex agnus-castus L. population were chosen to investigate different parameters such as comminution, maturity, distillation period and extraction method influencing the essential oil yield and composition. The effect of the comminution and the maturity of the plant material showed highly significant differences in yield and composition of the essential oils obtained, as well as the distillation duration from one to five hours and the method applied (hydrodistillation and simultaneous distillation extraction). The variation of 36 essential oil components due to the parameters applied was studied. The results showed that many different essential oil qualities can be obtained from the same plant material according to the parameters employed in its extraction. Entire fruits hydrodistilled for one hour yielded an oil much richer in monoterpene hydrocarbons and oxygenated compounds whereas the best combination to obtain an oil rich in less volatile compounds is by SDE of comminuted fruits for five hours. For mature fruits the main components varied as follows due to the parameters studied: sabinene 16.4-44.1%, 1,8-cineole 8.4-15.2%, beta-caryophyllene 2.1-5.0%, and trans-beta-farnesene 5.0-11.7%.