Electrostatic complexation of negatively charged polysaccharides with β-lactoglobulin (β-lg) has been shown to bolster the protein films at oil/water interfaces thereby improving emulsion stability. However, recent sub-phase exchange experiments demonstrated that highly charged polysaccharides such as low methyl-esterified pectin are complementary only if sequentially introduced to a pre-formed interfacial β-lg film. In this study, results of transient interfacial shear rheology show that, by using high-methylesterified pectins instead, complexes can be formed in pre-mixed solutions with β-lg at pH 4 that can lead to reinforced protein films at dodecane/water interfaces. Using this one-shot adsorption of such complexes, pectins as well as short chain polysaccharides like homogalacturonan nearly doubled the steady state shear elastic moduli as compared to that of a pure β-lg film. The lag times of film formation were established to be primarily decided by the charge density and pattern on the polysaccharide. Based on the results from mixed solutions of β-lg monomers, it is proposed that the polysaccharide at pH 4 strengthens the resulting interfacial layer by concatenating adsorbed β-lg molecules thereby establishing cross-links in the aqueous phase.

中文翻译：

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β-乳球蛋白和高甲基酯化果胶的复合物作为增强油/水界面的一次性输送系统

带负电荷的多糖与 β-乳球蛋白 (β-lg) 的静电络合已被证明可加强油/水界面处的蛋白质膜，从而提高乳液稳定性。然而，最近的亚相交换实验表明，高电荷多糖（如低甲基酯化果胶）仅在顺序引入预先形成的界面 β-lg 膜时才具有互补性。在这项研究中，瞬态界面剪切流变学的结果表明，通过使用高甲基酯化果胶，可以在 pH 4 的 β-lg 预混合溶液中形成复合物，从而在十二烷/水界面处形成增强的蛋白质膜。使用这种复合物的一次性吸附，与纯 β-lg 膜相比，果胶以及短链多糖（如同型半乳糖醛酸聚糖）的稳态剪切弹性模量几乎翻了一番。确定成膜的滞后时间主要由多糖上的电荷密度和模式决定。根据 β-lg 单体混合溶液的结果，建议 pH 值为 4 的多糖通过连接吸附的 β-lg 分子从而在水相中建立交联来增强所得界面层。