Flavan-3-ol compositional changes in grape berries (Vitis vinifera L. cv Cabernet Franc) before veraison, using two complementary analytical approaches, HPLC reversed phase and histochemistry

The interest and the limits of these approaches are described and discussed. Moreover, it is shown that the linking of these two analytical techniques which associates quantitative data and the spatializing of the tannins in cellular tissue could improve the understanding of the setting of the proanthocyanidins content. Finally, this original approach pointed out the importance of the period previous ripening in the synthesis of flavan-3-ols in the skin; the heterogeneity among berries was in relation with the stage of development but some other factors, as light exposition could also play a role.