Grape and wine amino acid composition from Carignan noir grapevines growing under rainfed conditions in the Maule Valley, Chile: Effects of location and rootstock.

Nitrogen compounds play a key role on grape and wine quality. Their composition in grapes depends mainly on variety, viticultural management, and terroir, and affects fermentation kinetics and the volatile compound formation. The aim of this work was to study grape and wine amino acid composition of ungrafted or grafted onto cv. País Carignan grapevines growing under rainfed conditions in ten sites of the Maule Valley (Chile). The results showed that proline was the most abundant amino acid in grapes and wines. In general, Carignan noir grapevines grafted over País showed lower grape amino acid content respect to ungrafted vines. Cool night index (CI) was inversely correlated to several amino acids, showing that their plant synthesis or accumulation increased with lower minimum temperatures during the last month before harvest. Truquilemu (Tru) and Ciénaga de Name (Cdn) sites showed the highest concentration for several amino acids and total amino acid content in grapes, which led to a faster alcoholic fermentation.

Influence of the use of fungicides on the volatile composition of Monastrell red wines obtained from inoculated fermentation.

The influence of six fungicides (famoxadone, fenhexamid, fluquinconazole, kresoxim-methyl, quinoxyfen and trifloxystrobin) on the volatile composition of red wines obtained from inoculated fermentation was studied. Although treatments were carried out under critical agricultural practices (CAP), the residues in the wines were below their maximum residue limit (MRL). Ethyl decanoate was the compound most influenced by these fungicides, while diethyl succinate, decanoic acid, ß-ionone, and citronellol concentration were not changed with any of the treatments. The treatment of grapes with trifloxystrobin induced changes in only one volatile compound, and the variation in volatile composition of wines from grapes treated with fenhexamid, fluquinconazole and quinoxyfen compared to control wines was almost negligible invaluable. The treatment with famoxadone influenced more volatile compounds than the other ones, except for wine from grapes treated with kresoxim-methyl, which was the only wine that showed a big change in its aromatic composition.