The highly hydrophilic nature of polysaccharides severely limits their application in oil-in-water emulsion. This work aimed to improve the emulsifying performance of Millettia speciosa Champ polysaccharide (MSCP) by adopting a modification strategy that covalently grafted the acetyl groups to the polysaccharide chains. Three acetylated polysaccharides (AC-MSCP1, AC-MSCP2 and AC-MSCP3) with different degrees of substitution (DS) were successfully prepared and characterized. Acetylation modification led to the degradation of MSCP and decrease in antioxidant ability. Compared with droplet size of MSCP formed emulsion (15.51 μm), a sharp decrease in droplet size of AC-MSCP stabilized emulsion (e.g. 0.24 μm for AC-MSCP2) was observed, which was even smaller than that of gum arabic (GA). Moreover, the emulsifying properties of AC-MSCP was regulated by multi-scale molecular structures. AC-MSCP1, with the lowest DS and molecular weight (MW), formed the largest droplets. AC-MSCP2, with a medium DS and MW, generated the smallest droplets, but droplet size was prone to increase due to low viscosity and electrostatic repulsion. AC-MSCP3, with the highest DS and the largest MW, formed bigger droplets than that of AC-MSCP2, but exhibited better emulsifying stability, owing to strong steric hindrance provided by its highest viscosity and thickest interfacial layer. Altogether, this study confirmed that acetylation modification was a promising method for improving the emulsifying performance of polysaccharide.

多糖的高度亲水性严重限制了它们在水包油乳液中的应用。本工作旨在提高鸡血藤的乳化性能Champ 多糖 (MSCP) 通过采用将乙酰基共价接枝到多糖链上的修饰策略。成功制备并表征了三种不同取代度（DS）的乙酰化多糖（AC-MSCP1、AC-MSCP2和AC-MSCP3）。乙酰化修饰导致 MSCP 降解和抗氧化能力下降。与MSCP形成的乳液的液滴尺寸（15.51μm）相比，观察到AC-MSCP稳定乳液的液滴尺寸急剧减小（例如AC-MSCP2为0.24μm），甚至小于阿拉伯树胶（GA）的液滴尺寸。此外，AC-MSCP 的乳化性能受多尺度分子结构的调控。具有最低 DS 和分子量 (MW) 的 AC-MSCP1 形成了最大的液滴。AC-MSCP2 具有中等 DS 和 MW，产生最小的液滴，但由于低粘度和静电排斥，液滴尺寸容易增加。AC-MSCP3 具有最高的 DS 和最大的 MW，形成比 AC-MSCP2 更大的液滴，但由于其最高的粘度和最厚的界面层提供了强大的空间位阻，因此表现出更好的乳化稳定性。总之，本研究证实乙酰化修饰是一种提高多糖乳化性能的有前途的方法。