title: 3-Sulfanyl-4-methylpentan-1-ol in Dry-Hopped Beers: First Evidence of Glutathione S-Conjugates in Hop (Humulus lupulus L.).
abstract: Monovarietal dry-hopped beers were produced with the dual-purpose hop cultivars Amarillo, Hallertau Blanc, and Mosaic. The grapefruit-like 3-sulfanyl-4-methylpentan-1-ol was found in all three beers at concentrations much higher than expected on the basis of the free thiol content in hop. Even cysteinylated precursors proved unable to explain our results. As observed in wine, the occurrence of S-glutathione precursors was therefore suspected in hop. The analytical standards of S-3-(4-methyl-1-hydroxypentyl)glutathione, never described before, and of S-3-(1-hydroxyhexyl)glutathione, previously evidenced in grapes, were chemically synthesized. An optimized extraction of glutathionylated precursors was then applied to Amarillo, Hallertau Blanc, and Mosaic hop samples. HPLC-ESI(+)MS/MS revealed, for the first time, the occurrence of S-3-(1-hydroxyhexyl)glutathione and S-3-(4-methyl-1-hydroxypentyl)glutathione in hop, at levels well above those reported for their cysteinylated counterparts. S-3-(1-Hydroxyhexyl)glutathione emerged in all cases as the major adduct in hop. Yet, although 3-sulfanylhexan-1-ol seems relatively ubiquitous in free, cysteinylated, and glutathionylated forms, the glutathione adduct of 3-sulfanyl-4-methylpentan-1-ol, never evidenced in other plants up to now, was found only in the Hallertau Blanc variety.
authors.affiliation: Unité de Brasserie et des Industries Alimentaires, Earth and Life Institute (ELIM), Université catholique de Louvain , Croix du Sud 2, Box L7.05.07, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Marie-Lucie
authors.initials: ML
authors.lastname: Kankolongo Cibaka
authors.affiliation: Unité de Brasserie et des Industries Alimentaires, Earth and Life Institute (ELIM), Université catholique de Louvain , Croix du Sud 2, Box L7.05.07, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Laura
authors.initials: L
authors.lastname: Decourrière
authors.affiliation: Unité de Brasserie et des Industries Alimentaires, Earth and Life Institute (ELIM), Université catholique de Louvain , Croix du Sud 2, Box L7.05.07, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Celso-José
authors.initials: CJ
authors.lastname: Lorenzo-Alonso
authors.affiliation: Unité de Brasserie et des Industries Alimentaires, Earth and Life Institute (ELIM), Université catholique de Louvain , Croix du Sud 2, Box L7.05.07, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Etienne
authors.initials: E
authors.lastname: Bodart
authors.affiliation: Institute of Condensed Matter and Nanosciences (IMCN), Université catholique de Louvain , Place Louis Pasteur 1, Box L4.01.02, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Robiette
authors.affiliation: Unité de Brasserie et des Industries Alimentaires, Earth and Life Institute (ELIM), Université catholique de Louvain , Croix du Sud 2, Box L7.05.07, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Sonia
authors.initials: S
authors.lastname: Collin
mesh_terms: D001515:Beer / Q000032:analysis*; D002208:Caproates / Q000737:chemistry*; D005978:Glutathione / Q000737:chemistry*; D027582:Humulus / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D053719:Tandem Mass Spectrometry
chemical_list: D002208:Caproates; D013438:Sulfhydryl Compounds; C018575:isocaproaldehyde; D005978:Glutathione
keywords: beer; dry-hopping; flavor; glutathione; hop (Humulus lupulus L.); polyfunctional thiols