皮克林乳液以其极好的稳定性和低毒性吸引了越来越多的关注。多年来，Pickering 乳液的乳化剂已从合成和无机颗粒演变为可食用的蛋白质、多糖、脂肪晶体等。在本研究中，我们使用酪蛋白酸钠 (SC) 作为 Pickering 乳化剂。通过亲核攻击和亲核取代与酪蛋白的伯氨基反应的京尼平交联后，原来的柔性亚胶束结构重新组装形成软蛋白颗粒。不同数量的交联剂产生从聚合物状到颗粒状的 SC 颗粒。结果发现，SC 的交联破坏了它们降低油水界面界面张力的能力，表明界面活性降低。还，具有不同交联密度的 SC 颗粒都可以稳定具有高储存稳定性的高内相乳液 (HIPE)，表明交联对水包油 (O/W) 乳液稳定性的影响很小。当谈到双乳液时，交联密度的影响就显露出来了。使用具有更高交联密度的 SC 可以获得更高的乳液稳定性。然而，在模拟消化过程中，SC 的交联被证明对乳液稳定性有不利影响。低 pH 值和高盐浓度导致高度交联的 SC 严重聚集，破坏了形成的双乳液的稳定性。另一方面，松散交联的 SC 及其保留的空间排斥力对双重乳液具有更好的保护作用。鉴于 Pickering 乳液在食品和药品领域的潜力，这项工作强调，简单地用 Pickering 乳化剂替代传统乳化剂并不能消除实际应用中的稳定性问题。可能有必要进一步研究颗粒状乳化剂与聚合物状乳化剂的结合或共轭。

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Pickering emulsions are attracting increasing attention with their superb stability and low toxicity. Over the years, the emulsifiers for Pickering emulsions have evolved from synthetic and inorganic particles to edible ones like protein, polysaccharides, fat crystals, etc. In this study, we utilized sodium caseinate (SC) as Pickering emulsifiers. Upon crosslinking with genipin which reacts with the primary amino groups of casein via the nucleophilic attack and nucleophilic substitution, the original flexible sub-micelle structure reassembled to form soft protein particles. Different amount of crosslinkers gave SC particles ranging from polymer-like to particle-like ones. It was found that crosslinking of SC undermined their ability to decrease the interfacial tension of the oil-water interface, indicating reduced interfacial activity. Also, SC particles with different crosslinking density could all stabilize high internal phase emulsions (HIPEs) with high storage stability, indicating little effect of crosslinking on the stability of oil-in-water (O/W) emulsions. When it comes to double emulsions, the effect of crosslinking density was revealed. A higher emulsion stability was achieved using SC with a higher crosslinking density. However, during simulated digestion, crosslinking of SC turned out to have an adverse effect on the emulsion stability. The low pH and the high salt concentration caused severe aggregation of highly crosslinked SC, undermining the stability of the formed double emulsions. On the other hand, loosely crosslinked SC with its preserved steric repulsion showed better protection for the double emulsions. Given the potential of Pickering emulsions in the field of foods and pharmaceuticals, this work emphasized that simply replacing conventional emulsifiers with Pickering emulsifiers would not eliminate the stability problem for practical applications. Further studies on the combination or conjugation of particle-like emulsifier with polymer-like ones might be necessary.