School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China.
School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310018, China.
Food Chem. 2022 Mar 1;371:131077. doi: 10.1016/j.foodchem.2021.131077. Epub 2021 Sep 15.
Egg yolk granules are supramolecular assembly of high-density lipoproteins and phosvitin driven by calcium bridges. However, applications of granules are severely restricted by the large particle size and poor water dispersibility. This study revealed the Janus effects of NaCl on structure of granules at varied pH values. Addition of 0.3-0.5 M NaCl led to the dissociation of at pH 5.0-7.0. At pH 5.0-10.0, dissociated granules demonstrated good colloidal stability with NaCl because of the adsorption of highly hydrated Na and Ca, which provided strong hydration repulsion when electrostatic repulsion was screened. In contrast, at pH 2.0 and 3.0, dissociated granules were positively charged with adsorption of poorly hydrated Cl as counterions. Cl failed to give sufficient hydration repulsion, leading to the phase separation with 0.3-0.5 M NaCl. Similar effects have been also found in LiCl, KCl, and CsCl, but Li might be less effective to disrupt calcium bridges.
蛋黄颗粒是由高密度脂蛋白和卵黄高磷蛋白通过钙离子桥形成的超分子组装体。然而，颗粒的应用受到其较大的粒径和较差的水分散性的严重限制。本研究揭示了 NaCl 在不同 pH 值下对颗粒结构的双面影响。在 pH 值为 5.0-7.0 时，添加 0.3-0.5 M NaCl 会导致颗粒解离。在 pH 值为 5.0-10.0 时，由于高度水合的 Na 和 Ca 的吸附，解离后的颗粒在 NaCl 存在下具有良好的胶体稳定性，因为静电排斥被屏蔽时，高度水合的 Na 和 Ca 提供了强烈的水化斥力。相比之下，在 pH 值为 2.0 和 3.0 时，解离后的颗粒带正电荷，吸附了较少水合的 Cl 作为抗衡离子。Cl 不能提供足够的水化斥力，导致与 0.3-0.5 M NaCl 发生相分离。在 LiCl、KCl 和 CsCl 中也发现了类似的效应，但 Li 可能对破坏钙离子桥的效果较小。
