Changes in the flavan-3-ol and polysaccharide content during the fermentation of Vitis vinifera Cabernet-Sauvignon and cold-hardy Vitis varieties Frontenac and Frontenac blanc

Grape variety has a significant impact on wine flavan-3-ol and polysaccharide profile. The main objective of this work was to study differences in flavan-3-ol and polysaccharide diffusion from grape to wine during the fermentative alcoholic maceration of three Vitis sp. varieties: the cold-hardy hybrid varieties Frontenac and Frontenac blanc, and the V. vinifera variety Cabernet-Sauvignon. Polysaccharides from must and wine were precipitated by ethanol and quantified using the phenol-sulfuric method of Dubois. Flavan-3-ol concentration and profile were analysed by HPLC-FLD. Results showed that wines from Frontenac and Frontenac blanc had less oligomeric and polymeric flavan-3-ols than those from V. vinifera Cabernet-Sauvignon. Wines made from Frontenac also had a higher concentration in total polysaccharides. Preliminary results from GPC/SEC analyses suggested that Frontenac wine had a higher content in mannoproteins and rhamnogalacturonan-2 polysaccharides compared to the other studied varieties. Overall, wines of Frontenac showed the highest content in total polysaccharides, and the lowest content in condensed tannins. As polysaccharides are known to negatively impact wine perceived astringency, these results suggest that significant attention should be given to the polysaccharide composition of cold-hardy cultivars in the context of cold climate wine production. Such knowledge may help winemakers from cold climate areas to improve the winemaking processes and final wine composition when working with cold-hardy Vitis sp. varieties. Knowledge on interspecific hybrid polysaccharide and flavan-3-ol kinetic during the alcoholic fermentative maceration may help the winemakers from cold climate areas to improve winemaking processes and final wine composition.