Influence of Vineyard Location on Physicochemical Properties, Phenolic Content, and Antioxidant Capacity of ‘Touriga Nacional’ Grapes Cultivated in Brazil and Portugal

The use of new grape cultivars is essential for the continued development of Brazilian viticulture. Thus, this study aimed to determine the general physicochemical parameters, global phenolic composition, and antioxidant capacity of grape musts from the Portuguese red variety ‘Touriga Nacional’ during ripening in two Brazilian vineyards (states of Rio Grande do Sul and Santa Catarina). The results were compared with data obtained from the same variety cultivated in a vineyard located in northern Portugal, which is the region of origin of this variety. This research was conducted over three consecutive vintages (2022–2024). Overall, the results indicated that soil and climate conditions at each location were associated with differences in the composition of ‘Touriga Nacional’ grape musts. Grapes from both Brazilian vineyards showed significantly higher berry weight, must volume, and yield compared with grapes collected from the Portuguese vineyard. On the other hand, grapes collected from the vineyard located in the state of Santa Catarina exhibited the highest values of total titratable acidity, malic acid, total phenols, flavonoids, total anthocyanins, and chromatic characteristics. Nevertheless, grapes collected from the Portuguese vineyard showed higher values of total tannins. The results suggest that the ‘Touriga Nacional’ variety shows better adaptation to the conditions of the Santa Catarina vineyard than to those of the Rio Grande do Sul vineyard. These findings help winegrowers, particularly in southern Brazil, to have more options for introducing different grape varieties, thereby contributing to the production of wines with distinctive characteristics, while consumers will have access to a greater diversity of wines available on the market.