Elucidation of the 1,3-sulfanylalcohol oxidation mechanism: an unusual identification of the disulfide of 3-sulfanylhexanol in sauternes botrytized wines

J Agric Food Chem. 2010 Oct 13;58(19):10606-13. doi: 10.1021/jf102022s.

Abstract

A four-step purification method was developed to isolate a citrus odorant detected by gas chromatography-olfactometry (GC-O), which was apparently specific to Sauternes botrytized wines. A fragmentation pattern of the odorant was obtained by multidimensional gas chromatography-mass spectrometry-olfactometry (MDGC-MS-O). The exact mass measurement was used to determine its elemental formula as C(6)H(12)OS. On the basis of these data, the unusual structure of 3-propyl-1,2-oxathiolane was synthesized and characterized for the first time. This confirmed its identification. Its occurrence in Sauternes wine extracts was demonstrated to result from the thermal oxidative degradation of 3-sulfanylhexanol disulfide (3,3'-disulfanediyldihexan-1-ol) in the GC injector. This disulfide was synthesized and then firmly identified for the first time in Sauternes wine. Although the presence of 3-sulfanylhexanol oxidation products had previously been reported in natural extracts (but not wine), the full oxidation pathway from 3-sulfanylhexanol to 3-propyl-γ-sultine via 3,3'-disulfanediyldihexan-1-ol was clearly established for the first time. Because the disulfide has mainly been detected in Sauternes botrytized wines, this finding suggested a singular reactivity of 3-sulfanylhexanol in botrytized wines, thus opening up a wide range of new opportunities in wine chemistry.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, Gas
  • Disulfides / analysis*
  • Gas Chromatography-Mass Spectrometry
  • Hexanols / analysis*
  • Hexanols / chemistry
  • Hot Temperature
  • Odorants / analysis
  • Oxidation-Reduction
  • Smell
  • Sulfhydryl Compounds / analysis*
  • Sulfhydryl Compounds / chemistry
  • Wine / analysis*

Substances

  • Disulfides
  • Hexanols
  • Sulfhydryl Compounds
  • 3-mercaptohexanol