title: Sensomics analysis of key bitter compounds in the hard resin of hops (Humulus lupulus L.) and their contribution to the bitter profile of Pilsner-type beer.
abstract: Recent brewing trials indicated the occurrence of valuable bitter compounds in the hard resin fraction of hop. Aiming at the discovery of these compounds, hop's ε-resin was separated by means of a sensory guided fractionation approach and the key taste molecules were identified by means of UV/vis, LC-TOF-MS, and 1D/2D-NMR studies as well as synthetic experiments. Besides a series of literature known xanthohumol derivatives, multifidol glucosides, flavon-3-on glycosides, and p-coumaric acid esters, a total of 11 bitter tastants are reported for the first time, namely, 1",2"-dihydroxanthohumol F, 4'-hydroxytunicatachalcone, isoxantholupon, 1-methoxy-4-prenylphloroglucinol, dihydrocyclohumulohydrochinone, xanthohumols M, N, and P, and isoxanthohumols M, N, and P, respectively. Human sensory analysis revealed low bitter recognition threshold concentrations ranging from 5 (co-multifidol glucopyranoside) to 198 μmol/L (trans-p-coumaric acid ethyl ester) depending on their chemical structure. For the first time, LC-MS/MS quantitation of these taste compounds in Pilsner-type beer, followed by taste re-engineering experiments, revealed the additive contribution of iso-α-acids and the identified hard resin components to be truly necessary and sufficient for constructing the authentic bitter percept of beer. Finally, brewing trails using the ε-resin as the only hop source impressively demonstrated the possibility to produce beverages strongly enriched with prenylated hop flavonoids.
authors: †Chair of Food Chemistry and Molecular and Sensory Science, Technische Universität München, Lise-Meitner-Straße 34, D-84354 Freising, Germany.
authors: Michael
authors: M
authors: Dresel
authors: †Chair of Food Chemistry and Molecular and Sensory Science, Technische Universität München, Lise-Meitner-Straße 34, D-84354 Freising, Germany.
authors: Andreas
authors: A
authors: Dunkel
authors: †Chair of Food Chemistry and Molecular and Sensory Science, Technische Universität München, Lise-Meitner-Straße 34, D-84354 Freising, Germany.|‡Bavarian Center for Biomolecular Mass Spectrometry, Gregor-Mendel-Straße 4, 85354 Freising, Germany.
authors: Thomas
authors: T
authors: Hofmann
mesh_terms: D001515:Beer / Q000032:analysis*; D005591:Chemical Fractionation; D002851:Chromatography, High Pressure Liquid; D003373:Coumaric Acids / Q000032:analysis; D005419:Flavonoids / Q000032:analysis; D005960:Glucosides / Q000032:analysis; D027582:Humulus / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D011422:Propionates; D011427:Propiophenones / Q000032:analysis; D012116:Resins, Plant / Q000737:chemistry*; D012677:Sensation; D013649:Taste
chemical_list: D003373:Coumaric Acids; D005419:Flavonoids; D005960:Glucosides; D011422:Propionates; D011427:Propiophenones; D012116:Resins, Plant; C495469:p-coumaric acid; C104536:xanthohumol
keywords: Humulus lupulus L.; bitter; hops; sensomics; taste dilution analysis; xanthohumol