Blend wines made of Syrah, Marselan and Tannat, had better color and more phenolic diversity than varietal wines

Abstract

Background: Elaborating red-wines from grape cultivars with different polyphenolic profiles could improve wine color and its phenolic-dependent characteristics. Aim: the aim of this research was to study the effect of elaborating blend wines from grape-cultivars with different phenolic profiles on, copigmentation, promotion of stable pigments, color, and contents of phenolic compounds. The time of blending, before-fermentation blends of musts (BFB) or after-fermentation blends of wines (AFB) was also evaluated. Material and Methods: During 2020 vintage, blend wines were made from grapes (m/m) or wines (v/v), in proportion of 1/2-1/2 of Tannat-Marselan, Tannat-Syrah, Syrah-Marselan, and 1/3-1/3-1/3 of Tannat-Syrah-Marselan. The varietal wines (VW) were also elaborated, all by triplicate at experimental scale. Spectrophotometric analysis (including total phenols, wine color, and antioxidant capacity measurements) were performed right-after wine stabilization, and a year later together with LC-DAD-MS/MS determinations (analysis of pigments, flavonols, flavan-3-ols, hydroxycinnamic acids and stilbenes). Wines and samples of the grape skin and seed used in the experiments were also analyzed. Results: Tannat wines had pigments with low proportion of malvidin and acylated derivatives, high contents of hydroxycinnamic acids, flavan-3-ols, and relative low contents of flavonols (mainly based on myricetin). Syrah wines had high proportion of malvidin and the highest of acylated derivatives, low contents of hydroxycinnamic acids, medium concentrations of flavan-3-ols, and high contents of flavonols, particularly based on quercetin and isorhamnetin. Marselan, showed high contents of anthocyanins, with the highest proportion of malvidin, high concentrations of hydroxycinnamic acids, flavan-3-ol and flavonols, with high proportion of syringetin. Thus, each cultivar expressed its characteristic phenolic profile. Copigmentation was significantly higher in Marselan than in Syrah, and in Syrah than in Tannat wines, but the blended wines that included Tannat and Marselan had the highest proportion of copigmentation, possibly due to a better relationship between pigments and copigments like flavonols. The BFB wines had higher and more bluish color than AFB wines, mainly due to BFB wines had significant lower pH that AFB (e.g. Marselan_Tannat CI 13.93 and 12.77 in BFB and AFB respectively). The BFB wines had higher color due to polymers than BAF and VW wines. Tri-varietal blends presented a more bluish hue than bi-varietal blends, maybe because of the better balance among pigments and compigments found in the formers. The wines made BFB had higher content of phenols in the wines after a year than the expected considering the proportion of each cultivar in the blend. Blend red-wines made considering grape-cultivar phenolic characteristics may improve wine quality.