Effect of different foliar nitrogen applications on the must amino acids and glutathione composition in Cabernet Sauvignon vineyard

The effect of different foliar nitrogen applications on the must amino acids and glutathione composition in a Cabernet Sauvignon vineyard was studied. Nitrogen treatments applied to the grapevines were urea (Ur), urea plus sulphur (Ur + S) and arginine (Arg). Also, two commercial nitrogen complexes, Basfoliar Algae (BA) and Nutrimyr Thiols (NT), were used. For each treatment, 2 kg N/ha was applied, divided in two applications. The commercial nitrogen complexes (NT and BA) improved the amino acid content. Ur + S treatment had a better assimilation than Ur, increasing the amino acid composition. Arg treatment did not increase the content of any amino acid, however increased the easily extractable anthocyanins, total anthocyanins and total polyphenol index. Organic sources treatments (Arg, NT and BA) increased glutathione concentration. These results can be of oenological interest to improve grape quality enhancing must amino acid and glutathione content in high proline accumulator variety.