Humulus lupulus (hop) cone is a key ingredient of beer, which determines its taste and aroma. Thus, it is necessary to control its cultivation conditions to acquire suitable quality. Here, cultivation conditions, such as pruning, blooming, and harvest timings, were modified for the Saaz hop variety in the Saaz region of Czech Republic. We investigated the correlation between the abovementioned cultivation factors and hop aroma characteristics, chemical components, appearance, yield, and beer quality in four locations and in three years. Harvest timing had a significant impact on the amount of essential oils, especially monoterpenes. Among them, linalool, geraniol and myrcene, which contribute beer hoppy aroma, increased with delay in harvest timing. These impacts caused by harvest timing were confirmed in all 4 locations and in all 3years. Our findings suggest that harvest timing influences the intensity and quality of beer hoppy aroma.

• Klíčová slova
• Beer, Cultivation, Harvest, Hop, Humulus lupulus, Pruning,
• MeSH
• acyklické monoterpeny MeSH
• alkeny analýza   MeSH
• barva MeSH
• chuť MeSH
• čich MeSH
• Humulus chemie   MeSH
• kvalita jídla MeSH
• manipulace s potravinami MeSH
• monoterpeny analýza   MeSH
• odoranty analýza   MeSH
• oleje prchavé analýza   MeSH
• pivo MeSH
• stavba rostlin chemie   MeSH
• terpeny analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• acyklické monoterpeny MeSH
• alkeny MeSH
• geraniol MeSH Prohlížeč
• linalool MeSH Prohlížeč
• monoterpeny MeSH
• myrcene MeSH Prohlížeč
• oleje prchavé MeSH
• terpeny MeSH

An efficient method combining the headspace solid-phase microextraction (HS-SPME) sampling procedure and comprehensive two-dimensional gas-chromatography/time-of-flight mass spectrometry (GC×GC/TOF-MS) was established to study the volatile secretion components of stink bugs (Heteroptera: Pentatomidae). The combined power of this approach is illustrated by the identification of fifty-seven compounds in the secretion of a European stink-bug representative, Graphosoma lineatum. (E)-4-oxohex-2-enal and (E)-dec-2-enal were found to be the major components in the adult bug secretions followed by lower amounts of n-alkenal (C₅-C₁₂), n-alkenyl acetate (C₅-C₁₁), n-alkane (C₁₁-C₁₇) homologs, dienals and other compounds. More than thirty known compounds have been identified that had not been described before in G. lineatum adults. Of these compounds, (E)-4-oxohex-2-enal is of particular interest, since its isolation and identification, while calling some previous reports into question, clearly demonstrates a potential ability of our approach to yield artifact-free secretion profiles.

• MeSH
• aldehydy analýza   MeSH
• alkeny analýza   MeSH
• Heteroptera chemie   fyziologie   MeSH
• mikroextrakce na pevné fázi metody   MeSH
• odoranty analýza   MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí metody   MeSH
• těkavé organické sloučeniny analýza   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• (2E)-decenal MeSH Prohlížeč
• 4-oxo-(E)-2-hexenal MeSH Prohlížeč
• aldehydy MeSH
• alkeny MeSH
• těkavé organické sloučeniny MeSH

Frontal gland contents of soldiers of three Prorhinotermes species, Prorhinotermes canalifrons, Prorhinotermes inopinatus, and Prorhinotermes simplex, consisted of two groups of compounds: nitroalkenes and sesquiterpene hydrocarbons. Analysis by gas chromatography-mass spectrometry revealed (E)-1-nitropentadec-1-ene as the major component of the glands with mean values of 152, 207, and 293 microg/individual for P. canalifrons, P. inopinatus, and P. simplex, respectively. Four other 1-nitroalkenes (C13, C14, C16, and C17), and two nitrodienes (C15 and C17) were also detected in the three species. The C17:1 nitroalkene was identified as (E)-1-nitroheptadec-1-ene. The sesquiterpene composition of the gland was species-specific: P. simplex contained (3Z,6E)-alpha-farnesene (mean of 39 microg/individual), while P. canalifrons and P. inopinatus contained the same compound (means of 0.5 and 1.5 microg/individual, respectively) as well as the (3E,6E) isomer (means of 1.8 and 0.7 microg/individual, respectively). Two other sesquiterpenes, trans-beta-bergamotene and (Z)-gamma-bisabolene, were also found in low quantities in the frontal gland of P. canalifrons.

• MeSH
• alkeny analýza   MeSH
• dusíkaté sloučeniny analýza   MeSH
• exokrinní žlázy metabolismus   MeSH
• feromony analýza   MeSH
• Isoptera metabolismus   MeSH
• seskviterpeny analýza   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• srovnávací studie MeSH
• Názvy látek
• alkeny MeSH
• dusíkaté sloučeniny MeSH
• feromony MeSH
• seskviterpeny MeSH

Liquid column chromatography and thin-layer chromatography were used to determine the total content of hydrocarbons and gas chromatography was used to evaluate composition of hydrocarbons in green algae (Chlorella kessleri, C. vulgaris, Chlorella sp., Scenedesmus acutus, S. acuminatus, S. obliquus) and the blue-green alga (Spirulina platensis) cultivated under autotrophic or heterotrophic conditions. In C. kessleri cultivated under heterotrophic conditions the content of hydrocarbons was found to be about 10(-2)% (per dry mass), whereas under autotrophic conditions it was about 10(-3)% (per dry mass). The highest content of hydrocarbons was detected in species of the genus Scenedesmus cultivated autotrophically (10(-1)%). Heptadecane and hexacosane were found as major alkanes, 1-heptadecene was detected among alkenes.

• MeSH
• alkany analýza   MeSH
• alkeny analýza   MeSH
• Chlorella analýza   MeSH
• Chlorophyta analýza   růst a vývoj   MeSH
• sinice analýza   růst a vývoj   MeSH
• uhlovodíky analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• alkany MeSH
• alkeny MeSH
• uhlovodíky MeSH