Nestlé Research Center, Vers-Chez-Les-Blanc, CH-1000 Lausanne 26, Switzerland.
Langmuir. 2013 Jul 2;29(26):8222-32. doi: 10.1021/la305052q. Epub 2013 Jun 21.
The phase behavior of the ternary unsaturated monoglycerides (UMG)-DL-α-tocopheryl acetate-water system has been studied. The effects of lipid composition in both bulk and dispersed lyotropic liquid crystalline phases and microemulsions were investigated. In excess water, progressive addition of DL-α-tocopheryl acetate to a binary UMG mixture results in the following phase sequence: reversed bicontinuous cubic phase, reversed hexagonal (H(II)) phase, and a reversed microemulsion. The action of DL-α-tocopheryl acetate is then compared to that of other lipids such as triolein, limonene, tetradecane, and DL-α-tocopherol. The impact of solubilizing these hydrophobic molecules on the UMG-water phase behavior shows some common features. However, the solubilization of certain molecules, like DL-α-tocopherol, leads to the presence of the reversed micellar cubic phase (space group number 227 and symmetry Fd3m) while the solubilization of others does not. These differences in phase behavior are discussed in terms of physical-chemical characteristics of the added lipid molecule and its interaction with UMG and water. From an applications point of view, phase behavior as a function of the solubilized content of guest molecules (lipid additive in our case) is crucial since macroscopic properties such as molecular release depend strongly on the phase present. The effect of two hydrophilic emulsifiers, used to stabilize the aqueous dispersions of UMG, was studied and compared. Those were Pluronic F127, which is the most commonly used stabilizer for these kinds of inverted type structures, and the partially hydrolyzed emulsifier lecithin (Emultop EP), which is a well accepted food-grade emulsifier. The phase behavior of particles stabilized by the partially hydrolyzed lecithin is similar to that of bulk sample at full hydration, but this emulsifier interacts significantly with the internal structure and affects it much more than F127.
已研究三元不饱和单甘油脂 (UMG)-DL-α-生育酚乙酸酯-水体系的相行为。研究了在大块和分散溶致液晶相和微乳液中脂质组成的影响。在过量水中，逐步向二元 UMG 混合物中添加 DL-α-生育酚乙酸酯会导致以下相序列：反连续立方相、反六边形 (H(II)) 相和反微乳液。然后将 DL-α-生育酚乙酸酯的作用与其他脂质（如三油酸甘油酯、柠檬烯、十四烷和 DL-α-生育酚）的作用进行比较。这些疏水分子的增溶对 UMG-水相行为的影响显示出一些共同的特征。然而，某些分子（如 DL-α-生育酚）的增溶会导致存在反胶束立方相（空间群数 227 和对称性 Fd3m），而其他分子的增溶则不会。这些相行为的差异是根据添加脂质分子的物理化学特性及其与 UMG 和水的相互作用来讨论的。从应用的角度来看，作为溶质分子（在我们的情况下为脂质添加剂）的增溶含量的函数的相行为是至关重要的，因为诸如分子释放之类的宏观性质强烈依赖于存在的相。研究并比较了两种亲水性乳化剂对 UMG 水相分散体的稳定作用。一种是最常用于这些类型的反转结构的 Pluronic F127，另一种是部分水解的乳化剂卵磷脂 (Emultop EP)，它是一种公认的食品级乳化剂。部分水解卵磷脂稳定的颗粒的相行为与完全水合时的大块样品相似，但这种乳化剂与内部结构相互作用显著，并比 F127 更强烈地影响它。
