Phenolic composition of skins and pulps of grapes for traditional sparkling wines in the Northeast of Brazil

Abstract

Among the compounds contributing to the grape and wine qualities, phenolics play an important role. Therefore, the objective of this study was to determine the phenolic compounds of skins and pulps of white and red grapes at harvest, destined to traditional sparkling wines, from two winegrowing regions producing tropical wines in the Northeast of Brazil. Chenin Blanc and Syrah were harvested in June 2015 in the São Francisco Valley, at 350 m of altitude, while Chardonnay and Pinot Noir grapes were harvested in September 2015 in the Chapada Diamantina-Bahia State, at 1,100 m of altitude. Twenty phenolics were determined by HPLC in skins and pulps separated manually and extracted using ethanol, each sample composed by 50 berries in triplicate. In the pulps of the white grapes, quercetin-3-glucoside (flavonol) was the most concentrated compound in Chardonnay (2.73 mg Kg^-1), while in Chenin Blanc was the galic acid (0.25 mg Kg^-1). In the red cultivars, the most concentrated compound determined in the pulps of Pinot Noir was quercetin-3-glucoside (1.89 mg Kg^-1), while in Syrah was epigallocatechin gallate (flavanol) (0.31 mg Kg^-1). In Chenin Blanc and Chardonnay skins, the most concentrated compound was quercetin-3-glucoside (9.20 and 129.30 mg Kg^-1, respectively). In the red grapes, the most concentrated compound was also the same for Pinot Noir and Syrah, the malvidin-3-glucoside anthocyanin (254.13 and 649.13 mg Kg^-1, respectively). It is interesting to highlight that not only cultivar effect collaborated to the phenolic profiles, but also the geographic localization of the winegrowing areas.