Effect of vine nitrogen status on grape aromatic potential : flavor precursors (S-cysteine conjugates) glutathione and phenolic content in Vitis vinifera L.cv.Sauvignon blanc grape juice
Effet de la nutrition azotée de la vigne sur le potentiel aromatique du raisin : précurseurs d'arômes (S-conjugués à la cystéine), glutathion et composés phénoliques dans le moût de Vitis vinifera L.cv.Sauvignon blanc
Résumé
Vine nitrogen status influence on S-cysteine conjugate precursors of volatile thiols, glutathione and phenolic content of the berries of Vitis vinifera L. cv. Sauvignon blanc have been assessed. Despite an increase in berry weight, the increase in nitrogen supply in the vine leads to higher cysteine precursor levels in grape juice. We also show that a late addition of nitrogen at berry set leads to a lower level of phenolic compounds in white grapes and to higher glutathione levels. Therefore, in white varieties, and particularly Sauvignon blanc, improving the nitrogen supply of the vine clearly increases its aromatic potential. However, an excess of nitrogen supply would increase the grape sensitivity to Botrytis cinerea and therefore decrease its quality.