Formation of Hydrogen Sulfide in Wine: Interactions between Copper and Sulfur Dioxide.
The combined synergistic effects of copper (Cu(2+)) and sulfur dioxide (SO₂) on the formation of hydrogen sulfide (H₂S) in Verdelho and Shiraz wine samples post-bottling was studied over a 12-month period. The combined treatment of Cu(2+) and SO₂ significantly increased H₂S formation in Verdelho wines samples that were not previously treated with either Cu(2+) or SO₂. The formation of H₂S produced through Cu(2+) mediated reactions was likely either: (a) directly through the interaction of SO₂ with either Cu(2+) or H₂S; or (b) indirectly through the interaction of SO₂ with other wine matrix compounds. To gain better understanding of the mechanisms responsible for the significant increases in H₂S concentration in the Verdelho samples, the interaction between Cu(2+) and SO₂ was studied in a model wine matrix with and without the presence of a representative thiol quenching compound (4-methylbenzoquinone, 4MBQ). In these model studies, the importance of naturally occurring wine compounds and wine additives, such as quinones, SO₂, and metal ions, in modulating the formation of H₂S post-bottling was demonstrated. When present in equimolar concentrations a 1:1 ratio of H₂S- and SO₂-catechol adducts were produced. At wine relevant concentrations, however, only SO₂-adducts were produced, reinforcing that the competition reactions of sulfur nucleophiles, such as H₂S and SO₂, with wine matrix compounds play a critical role in modulating final H₂S concentrations in wines.
The Australian Wine Research Institute, P.O. Box 197, Glen Osmond, 5064 South Australia, Australia. marlize.bekker@awri.com.au.
Marlize Z
MZ
Bekker
The Australian Wine Research Institute, P.O. Box 197, Glen Osmond, 5064 South Australia, Australia. mark.smith@awri.com.au.
Mark E
ME
Smith
The Australian Wine Research Institute, P.O. Box 197, Glen Osmond, 5064 South Australia, Australia. paul.smith@awri.com.au.
Paul A
PA
Smith
The Australian Wine Research Institute, P.O. Box 197, Glen Osmond, 5064 South Australia, Australia. eric.wilkes@awri.com.au.
Eric N
EN
Wilkes
D003300:Copper / Q000737:chemistry*; D006862:Hydrogen Sulfide / Q000737:chemistry*; D013458:Sulfur Dioxide / Q000737:chemistry*; D014920:Wine
D013458:Sulfur Dioxide; D003300:Copper; D006862:Hydrogen Sulfide
copper; hydrogen sulfide; quinone; reductive aromas; sulfur dioxide; wine