Sulfur Aroma Precursor Present inS-glutathione Conjugate Form: Identification ofS-3-(Hexan-1-ol)-glutathione in Must fromVitis viniferaL. cv. Sauvignon Blanc

When Sauvignon blanc or Gros Manseng grape must was percolated through an immobilized γ-glutamyltranspeptidase column, there was a significant increase in the concentration of S-3-(hexan-1-ol)-l-cysteine, the precursor of 3-mercaptohexan-1-ol, a compound that contributes to the varietal aroma of wines made from these grapes. Low- and high-resolution liquid secondary ion mass sepectrometry (LSIMS) analyses established the presence of S-3-(hexan-1-ol)-glutathione in Sauvignon blanc must. The identification of this compound suggests that the S-3-(hexan-1-ol)-l-cysteine in grapes is produced by the catabolism of S-3-(hexan-1-ol)-glutathione. As is the case in other plant or animal organisms, S-glutathione conjugates may be involved in certain detoxification systems in vines. Keywords: Vitis vinifera; Sauvignon blanc; varietal aroma precursors; S-cysteine conjugate; S-glutathione conjugate; aroma potential; tryptophanase; γ-glutamyltranspeptidase; LSIMS