Matrix effect of hydroxycinnamic acids on chromatic properties and phenolic profile of Cabernet Sauvignon dry red wine

The effect of adding hydroxycinnamic acids (caffeic acid, sinapic acid, p-coumaric acid and chlorogenic acid) in Cabernet Sauvignon dry red wine before and after fermentation was investigated, taking into account the color parameters, anthocyanin content, and overall polyphenol levels in the wine samples. The copigmentation effect of malvidin-3-O-glucoside and sinapic acid was further explored in model solution and through theoretical calculations. The results indicated that the addition of hydroxycinnamic acids significantly enhanced the wine's color with sinapic acid (before the fermentation) showing the most pronounced color protection effect. Compared to control samples, the addition of hydroxycinnamic acids resulted in a 36% increase in total phenolic content and a 28% increase in total anthocyanin content. Thermodynamic analysis revealed that the interaction between sinapic acid and malvidin-3-O-glucoside was spontaneous and exothermic. Theoretical studies identified hydrogen bonding (HB) and dispersion forces as the main primary stabilizing forces, with the carboxyl group of sinapic acid playing a critical role while the anthocyanin backbone also influenced the interaction.