乳脂球的表面性质决定了它们与酪蛋白的相互作用：均质化和通过AFM力谱探测pH的作用。,Colloids and Surfaces B: Biointerfaces

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乳脂球的表面性质决定了它们与酪蛋白的相互作用：均质化和通过AFM力谱探测pH的作用。
Colloids and Surfaces B: Biointerfaces ( IF 5.4 ) Pub Date : 2019-07-14 , DOI: 10.1016/j.colsurfb.2019.110363
Sameh Obeid ₁ , Fanny Guyomarc'h ₁ , Grégory Francius ₂ , Hervé Guillemin ₃ , Xiaoxi Wu ₁ , Stéphane Pezennec ₁ , Marie-Hélène Famelart ₁ , Chantal Cauty ₁ , Frédéric Gaucheron ₄ , Christelle Lopez ₁

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乳脂球的表面由富含极性脂质和糖蛋白的生物膜组成。但是，均质化过程中施加的高剪切应力会破坏膜并导致酪蛋白胶束作为牛奶的主要蛋白质组分吸附。界面特性的这些变化可能会影响中性pH值和酸化条件下天然或均质乳脂小球与周围蛋白质基质之间的相互作用。在这项研究中，宏观流变学，显微镜观察，纳米级基于AFM的力谱和理化分析相结合，以检查乳脂球的界面组成和结构，并评估它们与酪蛋白胶束的相互作用。我们证明了乳脂小球的表面特性（生物膜vs. 酪蛋白）和pH值控制它们与酪蛋白胶束的相互作用。均质化后，单个脂肪球与酪蛋白胶束之间的粘附力更高，尤其是在酸性pH值下，天然和均质脂肪球的粘附力分别从3.3 x 10-18增至14 x 10-18J。因此，酪蛋白包被的均质脂肪小球可产生较硬的牛奶酸凝胶。这些发现揭示了胶体颗粒的表面特性和pH值在与周围基质之间的连通性的重要性，从而调节了整体的微观结构和流变特性，并可能产生功能性后果，例如乳脂消化。特别是在酸性pH下，天然脂肪球和均质脂肪球的粘附功分别从3.3 x 10-18增加到14 x 10-18J。因此，酪蛋白包被的均质脂肪小球可产生较硬的牛奶酸凝胶。这些发现揭示了胶体颗粒的表面特性和pH值在与周围基质之间的连通性的重要性，从而调节了整体的微观结构和流变特性，并可能产生功能性后果，例如乳脂消化。特别是在酸性pH下，天然脂肪球和均质脂肪球的粘附功分别从3.3 x 10-18增加到14 x 10-18J。因此，酪蛋白包被的均质脂肪小球可产生较硬的牛奶酸凝胶。这些发现揭示了胶体颗粒的表面特性和pH值在与周围基质之间的连通性的重要性，从而调节了整体的微观结构和流变特性，并可能产生功能性后果，例如乳脂消化。

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The surface properties of milk fat globules govern their interactions with the caseins: Role of homogenization and pH probed by AFM force spectroscopy.

The surface of milk fat globules consists of a biological membrane rich in polar lipids and glycoproteins. However, high shear stress applied upon homogenization disrupts the membrane and leads to the adsorption of casein micelles, as the major protein fraction of milk. These changes in the interface properties could affect the interactions between native or homogenized milk fat globules and the surrounding protein matrix, at neutral pH and upon acidification. In this study, macroscale rheometry, microscopic observations, nanoscale AFM-based force spectroscopy and physico-chemical analysis were combined to examine the interfacial composition and structure of milk fat globules and to evaluate their interactions with casein micelles. We showed that the surface properties of milk fat globules (biological membrane vs. caseins) and pH govern their interactions with casein micelles. The adhesion between individual fat globules and casein micelles was higher upon homogenization, especially at acid pH where the work of adhesion increased from 3.3 x 10-18 to 14 x 10-18 J for native and homogenized fat globules, respectively. Consequently, casein-coated homogenized fat globules yield stiffer milk acid gels. These findings cast light on the importance of colloidal particle's surface properties and pH on their connectivity with the surrounding matrix, which modulates the bulk microstructure and rheological properties with potential functional consequences, such as milk lipid digestion.

更新日期：2019-07-14

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