Copigmentation effect of three phenolic acids on color and thermal stability of Chinese bayberry anthocyanins

The copigmentation effects of three phenolic acids (ferulic acid, sinapic acid, and syringic acid) on the color and thermal stability of Chinese bayberry anthocyanins were investigated. The three copigments of ferulic acid, sinapic acid, and syringic acid were found to have significant effects on the color enhancement of bayberry anthocyanins (p < .05). The maximum absorption wavelength of the anthocyanin aqueous solution exhibited a bathochromic shift, L* decreased, and a* increased with the increase in the molar ratio of copigments. The thermal stability of bayberry anthocyanins was significantly improved after copigmentation. No new anthocyanin derivatives appeared after copigmentation. The thermodynamic parameters (ΔG, ΔH, ΔS) of the three processes were all negative, indicating the three copigmentations were generally spontaneous and exothermic. The equilibrium constant (K) of the sinapic acid group was the greatest among the three phenolic acids, indicating that sinapic acid was more effective in stabilizing the anthocyanins.