title: Use of hydrodistillation and headspace solid-phase microextraction to characterize the volatile composition of different hop cultivars.
abstract: BACKGROUND
  Hop cones, the immature inflorescences of the female plant of Humulus lupulus L., have been used for centuries to improve the flavor of beer and can be also used for a great variety of other products. Four samples of hop, belonging to three different cultivars (Nugget, Saaz and Perle), were studied in the present work. Headspace solid-phase microextraction and hydrodistillation techniques were used to obtain the volatile profiles of the samples.
  
  
  RESULTS
  Independent of the technique employed, over 40 volatile compounds were detected in the hop pellet samples (esters, monoterpenes, monoterpenoids, sesquiterpenes and sesquiterpenoids). Sesquiterpenes and sesquiterpenoids represented the majority of the total aromatic compounds. The main compounds for all cultivars were myrcene, β-caryophyllene and humulene, but the presence of high amounts of β-farnesene in Saaz cultivar was highlighted.
  
  
  CONCLUSIONS
  Both techniques were suitable for studying qualitatively the volatile composition of hop pellets, but some differences were shown when studying the proportion of the main constituents of the volatile profiles. Understanding these differences may help researchers design future studies to advise the industry how to exploit the potential of each hop cultivar.
authors.affiliation: Chemical Engineering Department, Faculty of Sciences, University of Vigo (Campus Ourense), Ourense, Spain. lvazquezara@uvigo.es
authors.forename: Laura
authors.initials: L
authors.lastname: Vázquez-Araújo
authors.forename: Raquel
authors.initials: R
authors.lastname: Rodríguez-Solana
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Cortés-Diéguez
authors.forename: José M
authors.initials: JM
authors.lastname: Domínguez
mesh_terms: D000080462:Acyclic Monoterpenes; D000475:Alkenes / Q000032:analysis; D001515:Beer; D057168:Distillation / Q000379:methods*; D027582:Humulus / Q000737:chemistry* / Q000145:classification; D056626:Inflorescence / Q000737:chemistry*; D000081222:Monocyclic Sesquiterpenes; D039821:Monoterpenes / Q000032:analysis; D009822:Oils, Volatile / Q000737:chemistry*; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes / Q000032:analysis*; D052617:Solid Phase Microextraction / Q000379:methods*; D013045:Species Specificity
chemical_list: D000080462:Acyclic Monoterpenes; D000475:Alkenes; D000081222:Monocyclic Sesquiterpenes; D039821:Monoterpenes; D009822:Oils, Volatile; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes; C062671:beta-farnesene; C509595:myrcene; C042686:humulene; C024714:caryophyllene