The copigmentation effect between malvidin-3--glucoside and caffeic acid was comprehensive inquiry on the model wine solution, theoretical simulation and real wine. Thermodynamic parameters were determined by UV/Visible spectroscopy and Isothermal titration calorimetry (ITC). Theoretical data were obtained employing a dispersion-corrected density functional approach. The effects in real wines were investigated by adding the caffeic acid during different fermentation periods. Results shown that the copigmentation reaction between caffeic acid and malvidin-3--glucoside is a spontaneous exothermic reaction driven by hydrogen bonding and dispersions forces. Computations show that the polyhydroxyl sugar moiety and phenolic hydroxyl groups are the key active sites. The addition of caffeic acid in post-alcohol fermentation samples evidences an improving color characteristics in the wine.

中文翻译：

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malvidin-3-O-葡萄糖苷和咖啡酸之间的分子间相互作用：结构和热力学表征及其对真实葡萄酒颜色品质的影响


通过模型酒溶液、理论模拟和真实酒对锦葵素-3-葡萄糖苷与咖啡酸的辅色效果进行了综合探究。热力学参数通过紫外/可见光谱和等温滴定量热法（ITC）测定。理论数据是采用色散校正密度泛函方法获得的。通过在不同发酵时期添加咖啡酸来研究对真实葡萄酒的影响。结果表明，咖啡酸与锦葵素-3-葡萄糖苷之间的辅助色素化反应是由氢键和分散力驱动的自发放热反应。计算表明多羟基糖部分和酚羟基是关键的活性位点。在酒精发酵后样品中添加咖啡酸证明了葡萄酒颜色特性的改善。