Assessing the aromatic potential of Cabernet Sauvignon and Merlot musts used to produce rose wine by assaying the cysteinylated precursor of 3-mercaptohexan-1-ol

The development of a method for assaying S-3-(hexan-1-ol)-L-cysteine, the c ysteinylated precursor of 3-mercaptohexan-1-ol (P-3MH), in must has made it possible to study its impact on the aromatic potential of Merlot and Caber net Sauvignon grape varieties used to produce rose wines in Bordeaux. The o riginal feature of this method is the purification of very small volumes of must (500 muL) containing P-3MH by affinity chromatography and gas-phase c hromatography coupled with mass spectrometry of the purified precursor in t rimethylsilylated derivative form. Assays of the cysteinylated precursor in Merlot and Cabernet Sauvignon grapes showed that it was mainly located in the grape skins (60%). Prolonged juice-skin contact increased the must's P- 3MH content, and this phenomenon was more marked at higher temperatures. As sessment of the aromatic potential of must used to produce rose wines by ch emical analysis of an S-cysteine conjugate is mentioned for the first time.