Chemical typicity of tropical tannat red wines from sub-middle São Francisco Valley, Brazil

Tannat is a Vitis vinifera cultivar with typically high phenolic compound contents, showing intense coloration, well-bodied, and great aging potential. However, even with this great potential, this variety is still commercially underexplored in the Sub-middle São Francisco Valley (SSFV). This work aimed to characterize the typicity of Tannat red wines from Sub-middle São Francisco Valley (SSFV), Brazil. In addition, the present work represents the first study featuring phenolic compounds quantification and antioxidant activity of Tannat in tropical climate wine-producing regions. Considering the condition of a short-applied maceration time during the winemaking, the tropical Tannat wine showed significant antioxidant activity and high phenolic contents. Trans-caftaric, malvidin-3-O-glucoside, and procyanidin B1 stood out among the phenolic compounds quantified, presenting Tannat with the potential to be an important grape variety to tropical wine-producing regions in Brazil, containing high contents of bioactive compounds. Previously results to compounds (-)-epigallocatechin gallate, procyanidin B2, quercetin-3-β-D-glucoside, pelargonidin-3-O-glucoside, chlorogenic acid, and piceatannol were not found in Tannat wines. Further studies are necessary to make the Tannat grape's adaptation better in tropical climate conditions, including investigating the phenolic profile and antioxidant activity of Tannat red wines with longer maceration times during the winemaking.

Graphical abstract

Effect of the cold pre-fermentative maceration and aging on lees times on the phenolic compound profile, antioxidant capacity and color of red sparkling wines

This was the first study evaluating the impact of cold pre-fermentative maceration using refrigeration on the nutraceutical quality and color of red sparkling wines elaborated with the cultivar Syrah, and the evolution of these variables with different autolysis times. The sparkling wines were elaborated using the traditional method with different maceration times (NM, 24 and 72 h) and aging on lees (3 and 18 months of autolysis). In the sequence, it was conducted the characterization of the phenolic compound profile by HPLC–DAD (n = 21), the antioxidant capacity (ABTS, DPPH, and FRAP assays), and the color (CIELab and CIEL*C*h systems). The total phenolic content (TPC) and antioxidant capacity (AOX) were higher with longer maceration (M72) and autolysis (18 months) times, reaching 453.54 mg L⁻¹ of TPC, and AOX above 2.11 mmol TEAC L⁻¹ by the three in vitro assays conducted. Cis-resveratrol, kaempferol-3-O-glucoside, quercetin-3-β-d-glucoside, isorhamnetin-3-O-glucoside, and petunidin-3-O-glucoside showed a good correlation (r > 0.8; P < 0.05) with the antioxidant capacity and were found in higher concentrations in the sparkling wines elaborated with maceration. In addition, maceration promoted a more intense red (a*) and saturated (C*) color. Thus, the results indicated that cold pre-fermentative maceration and autolysis positively influenced the bioactive potential and the color of the red sparkling wines. This practice should be better explored through the elaboration of this product.