Abstract: In this study, two co-pigments, caffeic acid and chlorogenic acid, were added separately during the fermentation of Cabernet Sauvignon red wine using two strategies: single addition and two-step addition. To systematically compare the effects of different types and strategies of co-pigment addition on the color and phenolic profile of wine, we performed sensory evaluation triangle tests and quantitative analyses of phenolic components including co-pigments, anthocyanins and their derivatives. Meanwhile, CIELab color parameters and co-pigmentation ratios were measured. In addition, a simulated maceration trial was conducted to validate the fermentation results. The results showed that the addition of both caffeic acid and chlorogenic acid during fermentation improved the color quality of wine, resulting in visually distinguishable differences from the control (ΔE*ab = 3.91–8.08). Caffeic acid resulted in a greater increase in red hue (higher a* value) and a stronger reduction in yellow hue (lower b* value and hab angle). Compared with the single addition, the two-step addition of caffeic acid resulted in a significantly higher average concentration of hydroxycinnamic acid (13.39 mg/L vs. 10.42 mg/L), leading to a higher ratio of co-pigmented anthocyanins (59.25% vs. 55.26%), as well as higher concentrations of anthocyanins and their derivatives (82.28 mg/L vs. 71.99 mg/L), flavan-3-ols (115.50 mg/L vs. 104.58 mg/L), and flavonols (28.31 mg/L vs. 24.67 mg/L). Overall, wines with split addition of caffeic acid and chlorogenic acid exhibited superior color quality. This study provides a theoretical basis for the scientific and efficient application of co-pigments in red wine production.

Key words: co-pigmentation; wine; fermentation; color; anthocyanins