Pham Anna C, Peng Kang-Yu, Salim Malinda, Ramirez Gisela, Hawley Adrian, Clulow Andrew J, Boyd Ben J
Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Parkville, VIC 3052, Australia.
SAXS/WAXS Beamline, Australian Synchrotron, ANSTO, Clayton, VIC 3168, Australia.
ACS Appl Bio Mater. 2020 May 18;3(5):3087-3098. doi: 10.1021/acsabm.0c00131. Epub 2020 May 4.
Lipids in mammalian milks such as bovine milk and human breast milk have been shown to self-assemble into various liquid crystalline materials during digestion. In this study, the direct correlation between the composition of the lipids from three types of mammalian milk, three brands of infant formulas (IFs), and soy milk and the liquid crystalline structures that form during their digestion was investigated to link the material properties to the composition. The self-assembly behavior was assessed using digestion coupled with small-angle X-ray scattering (SAXS). Lipid composition was determined during digestion using liquid chromatography-mass spectrometry. All tested milks self-assembled into ordered structures during digestion, with the majority of milks displaying nonlamellar phases. Milks that released mostly long-chain fatty acids (>95 mol % of the top 10 fatty acids released) with more than 47 mol % unsaturation predominantly formed a micellar cubic phase during digestion. Other milks released relatively more medium-chain fatty acids and medium-chain monoglycerides and produced a range of ordered liquid crystalline structures including the micellar cubic phase, the hexagonal phase, and the bicontinuous cubic phase. One infant formula did not form liquid crystalline structures at all as a consequence of differences in fatty acid distributions. The self-assembly phenomenon provides a powerful discriminator between different classes of nutrition and a roadmap for the design of human milklike systems and is anticipated to have important implications for nutrient transport and the delivery of bioactives.
诸如牛乳和人乳等哺乳动物乳汁中的脂质在消化过程中已被证明会自组装成各种液晶材料。在本研究中，研究了三种类型的哺乳动物乳汁、三个品牌的婴儿配方奶粉（IFs）以及豆奶中的脂质组成与它们在消化过程中形成的液晶结构之间的直接关联，以将材料特性与组成联系起来。使用消化结合小角X射线散射（SAXS）来评估自组装行为。在消化过程中使用液相色谱 - 质谱法测定脂质组成。所有测试的乳汁在消化过程中都自组装成有序结构，大多数乳汁呈现非层状相。在消化过程中，释放出大部分长链脂肪酸（释放的前10种脂肪酸中>95摩尔%）且不饱和脂肪酸含量超过47摩尔%的乳汁主要形成胶束立方相。其他乳汁释放出相对较多的中链脂肪酸和中链甘油单酯，并产生一系列有序的液晶结构，包括胶束立方相、六方相和双连续立方相。由于脂肪酸分布的差异，一种婴儿配方奶粉根本没有形成液晶结构。自组装现象为区分不同类别的营养物质提供了有力的鉴别方法，并为设计类人乳系统提供了路线图，预计对营养物质运输和生物活性物质的递送具有重要意义。
