Influence of grape-harvesting steps on varietal thiol aromas in Sauvignon blanc wines
Allen, T.; Herbst-Johnstone, M.; Girault, M.; Butler, P.; Logan, G.; Jouanneau, S.; Nicolau, L.; Kilmartin, P. A.; Journal of Agricultural and Food Ch
The intense tropical fruit aroma of Sauvignon blanc wines has been found to be associated with the varietal thiols 3-mercaptohexanol (3MH), derived from odourless precursors in the grape, and 3-mercaptohexyl acetate (3MHA), arising from 3MH during fermentation.
Grapes and juice were sourced from 5 locations in Marlborough, New Zealand, taking hand-picked grapes and samples at 4 stages during the mechanical harvesting process and pressing, which were then fermented in replicated 750 ml bottles.
With each set of juices, the highest concn. of Cys-3MH and Glut-3MH were found in the juices pressed to 1 bar, but these juices produced wines with lower 3MH and 3MHA concn.
With 3 of the juices, there was an increase in varietal thiol content for wines made from juices that had been machine harvested compared with that of wine produced using the hand-picked grapes; these results matched earlier findings of lower 3MH and 3MHA levels in wines made from hand-picked grapes.
Juices that were more oxidized, which showed a higher absorbance at 420 nm, produced wines with lower 3MH and 3MHA concn
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Published on 09/12/2012