title: Novel technological strategies to enhance tropical thiol precursors in winemaking by-products.
abstract: Grape pomace is a winemaking by-product that can be used to extract oenological tannins. Recently, some grape skin tannins were shown to contain very high amounts of two polyfunctional thiol precursors (3-S-glutathionylhexan-1-ol, 3-S-cysteinylhexan-1-ol) whose free forms are responsible for appreciated tropical-like flavours. This study shows that an oxidative treatment (no SO2) of white grape pomace and the presence of grape leaves and stems can increase the content of the above mentioned precursors. Moreover, it shows significant differences between Sauvignon Blanc, Gewuerztraminer and Mueller-Thurgau grape pomace for the 3-mercaptohexan-1-ol precursors and 4-S-cysteinyl-4-methylpentan-2-one. The grape cultivar is crucial, but the technological ability of enhancing the level of the volatile thiol precursors simply by treating the grape marc in different ways is a promising and powerful tool for the production of potentially flavouring tannins intended for food and beverage industry.
authors.affiliation: FEM-IASMA Fondazione Edmund Mach - Istituto Agrario di San Michele all'Adige, via E. Mach 1, 38010 San Michele all'Adige (TN), Italy.
authors.forename: Tomás
authors.initials: T
authors.lastname: Román Villegas
authors.affiliation: FEM-IASMA Fondazione Edmund Mach - Istituto Agrario di San Michele all'Adige, via E. Mach 1, 38010 San Michele all'Adige (TN), Italy.
authors.forename: Loris
authors.initials: L
authors.lastname: Tonidandel
authors.affiliation: Wine Science Programme, School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Bruno
authors.initials: B
authors.lastname: Fedrizzi
authors.affiliation: FEM-IASMA Fondazione Edmund Mach - Istituto Agrario di San Michele all'Adige, via E. Mach 1, 38010 San Michele all'Adige (TN), Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Larcher
authors.affiliation: FEM-IASMA Fondazione Edmund Mach - Istituto Agrario di San Michele all'Adige, via E. Mach 1, 38010 San Michele all'Adige (TN), Italy. Electronic address: giorgio.nicolini@fmach.it.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Nicolini
mesh_terms: D006801:Humans; D010084:Oxidation-Reduction; D013439:Sulfhydryl Reagents / Q000737:chemistry*; D013634:Tannins / Q000378:metabolism*; D027843:Vitis / Q000737:chemistry*; D014920:Wine / Q000032:analysis*
chemical_list: D013439:Sulfhydryl Reagents; D013634:Tannins
keywords: Grape skin; Leaves; SO(2); Stems; Tannin; Varietal thiols