title: Identification and quantification of the oxidation products derived from α-acids and β-acids during storage of hops ( Humulus lupulus L.).
abstract: α-Acids and β-acids, two main components of hop resin, are known to be susceptible to oxygen and degraded during hop storage, although the oxidation products in stored hops have not been fully identified. In this study, we developed a high-performance liquid chromatography (HPLC) analysis method suitable for separation and quantification of the oxidation products. This HPLC analysis clearly proved, for the first time, that humulinones and hulupones are major products in oxidized hops. We are also the first to identify novel 4'-hydroxy-allohumulinones, suggested to be oxidative products of humulinones, by means of NMR spectroscopy and high-resolution mass spectrometry. Using the developed analytical method, changes in α- and β-acids and their oxidation products during hop storage were clearly revealed for the first time.
authors.affiliation: Research Laboratories for Health Science & Food Technologies, Research & Development Division, KIRIN Company, Ltd. , 1-13-5, Fukuura, Kanagawa 236-0004, Japan. Yoshimasa_Taniguchi@kirin.co.jp
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Taniguchi
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Matsukura
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ozaki
authors.forename: Koichi
authors.initials: K
authors.lastname: Nishimura
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Shindo
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D053138:Cyclohexenes / Q000032:analysis; D005519:Food Preservation; D027582:Humulus / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D012116:Resins, Plant / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013729:Terpenes / Q000032:analysis
chemical_list: D053138:Cyclohexenes; D012116:Resins, Plant; D013729:Terpenes; C007966:humulon