Université Bordeaux 1, TREFLE UMR CNRS 8508, ENSCBP, 16 avenue Pey Berland, 33607 Pessac, France.
Langmuir. 2010 Jun 15;26(12):9250-60. doi: 10.1021/la100078b.
Water-in-oil-in-water (W/O/W) double emulsions were prepared and the rate of release of magnesium ions from the internal to the external aqueous phase was followed. Sodium caseinate was used not only as a hydrophilic surface-active species but also as a chelating agent able to bind magnesium ions. The release occurred without film rupturing (no coalescence). The kinetics of the release process depended on the location (in only one or in both aqueous compartments) and on the concentration of sodium caseinate. The rate of release increased with the concentration of sodium caseinate in the external phase and decreased when sodium caseinate was present in the inner droplets. The experiments were interpreted within the frame of a mean-field model based on diffusion, integrating the effect of ion binding. The data could be adequately fitted by considering a time-dependent permeation coefficient of the magnesium ions across the oil phase. Our results suggested that ion permeability was influenced by the state of the protein interfacial layers which itself depended on the extent of magnesium binding.
制备了油包水包水（W/O/W）双重乳液，并跟踪了镁离子从内部水相向外部水相释放的速率。酪蛋白酸钠不仅可用作亲水表面活性剂，还可用作螯合剂，能够结合镁离子。释放过程没有膜破裂（没有聚结）。释放过程的动力学取决于位置（仅在一个或两个水相中）和酪蛋白酸钠的浓度。当外部相中的酪蛋白酸钠浓度增加时，释放速率增加，而当内部液滴中存在酪蛋白酸钠时，释放速率降低。实验结果在基于扩散的平均场模型的框架内进行了解释，该模型整合了离子结合的影响。通过考虑镁离子穿过油相的时变渗透系数，可以很好地拟合数据。我们的结果表明，离子渗透性受蛋白质界面层状态的影响，而蛋白质界面层状态本身又取决于镁结合的程度。
