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, anthocyanins and other polyphenols 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. Furthermore, the content of total phenols and total anthocyanins increased by 36% and 28%, respectively. Thermodynamic analysis revealed that the interaction between sinapic acid and malvidin-3- O -glucoside was spontaneous and exothermic. Theoretical studies identified hydrogen bonding and dispersion forces as the main contributors to binding, with the carboxyl group of sinapic acid playing a critical role, while the anthocyanin backbone also influenced the interaction.