Evolution of 3-mercaptohexanol, hydrogen sulfide, and methyl mercaptan during bottle storage of Sauvignon Blanc wines. Effect of glutathione, copper, oxygen exposure, and closure-derived oxygen.

The effects of wine composition and postbottling O2 exposure on 3-mercaptohexanol (3-MH), hydrogen sulfide (H2S), and methyl mercaptan (MeSH) were investigated. A Sauvignon Blanc wine with initial Cu concn. of 0.1 mg/l was treated with copper sulfate and/or glutathione (GSH) prior to bottling to give final concn. of 0.3 and 20 mg/l, respectively. The wines were bottled with a synthetic closure previously stored in either ambient air or N to study the effect of the O2 normally present in the closure. Bottled wines were stored for 6 months in either air or N to study the effect of O2 ingress through the closure. Cu addition resulted in a rapid initial decrease in 3-MH. During storage, a further decrease of 3-MH was observed, which was lower with GSH addition and lowered O2 exposure. H2S accumulated largely during the 2nd 3 months of bottle storage, with the highest concn. attained in the wines treated with GSH and Cu. Lower O2 from and through the closure promoted H2S accumulation. The concn. of MeSH was virtually not affected by the experimental variables at 6 months, although differences were observed after 3 months of storage. The implications for wine quality are discussed (We recommend that you consult the full text of this article)