Stability of emulsions containing sodium caseinate and dextran sulfate: Relationship to complexation in solution
Stability of emulsions containing sodium caseinate and dextran sulfate: Relationship to complexation in solution
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DOI：
10.1016/j.foodhyd.2007.01.007
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发表时间：
2008-06-01
影响因子：
10.7
通讯作者：
Dickinson, Eric
中科院分区：
文献类型：
--
作者：
Jourdain, Laureline;Leser, Martin E.;Dickinson, Eric
研究了在不同pH和离子强度条件下添加阴离子多糖硫酸葡聚糖(DS)对含有酪蛋白酸钠(CN)的水包正十四烷乳液性能的影响。使用两种方法制备乳液（20 vol%油、0.5 wt% CN、0.1-1 wt% DS）。在“双层乳液”中，乳化后将 DS 添加到 CN 稳定的乳液中；在“混合乳液”中，油直接乳化到混合生物聚合物溶液中。在 pH = 6 时，发现 DS 吸附在 CN 涂层液滴上，并且在 0.1 wt% DS 时由于桥接絮凝而发生广泛聚集。在较高的多糖浓度（1 wt% DS）下观察到聚合物稳定化。在混合乳液中，在任何 DS 浓度下均未观察到桥连絮凝。两种制备方法的这些对比结果表明，当pH值高于蛋白质的等电点时，就已经存在强烈的相互作用，并且两组系统在油水界面处的吸附层的结构是不同的。当含有 0.5 wt% DS 或更少的乳液的 pH 值降低至酸性值时，观察到沉淀。发现含有 1 wt% DS 的混合双层乳液在 pH = 2 时比不含 DS 的乳液更稳定。含有 1 wt% DS 的混合乳液在静态储存 3 周后表现出良好的保质期稳定性，特别是在低 pH 条件下制备乳液时。当 0.1 或 0.5 M NaCl 存在时，复合物被发现解离，这表明 CN 和 DS 之间的缔合相互作用主要是静态的。 (c) 2007 Elsevier Ltd. 保留所有权利。
The effect of addition of the anionic polysaccharide dextran sulfate (DS) on the properties of n-tetradecane-in-water emulsions containing sodium caseinate (CN) has been Studied under different pH and ionic strength conditions. Two methods were used for preparation of the emulsions (20 vol% oil, 0.5 wt% CN, 0.1-1 wt% DS). in 'bilayer emulsions', the DS was added to a CN-stabilized emulsion after emulsification; in 'mixed emulsions', the oil was directly emulsified into the mixed biopolymer solution. At pH = 6, DS Was found to adsorb onto CN-coated droplets, and extensive aggregation due to bridging flocculation occurred at 0.1 wt% DS. Polymeric stabilization was observed Lit higher polysaccharide concentration (1 wt% DS). In the mixed emulsions, no bridging flocculation was observed Lit any DS concentrations. These contrasting results for the two preparation methods indicate that strong interactions are present already Lit a pH value above the isoelectric point of the protein, and that the structure of the adsorbed layer at the oil-water interface is different for the two sets of systems. When the pH of emulsions containing 0.5 wt% DS or less was lowered towards acidic Values, precipitation was observed. The mixed and bilayer emulsions containing 1 wt% DS were found to be more stable at pH = 2 than the emulsion without DS. Mixed emulsions containing 1 wt% DS exhibited good shelf-life stability on quiescent storage for 3 weeks, especially when the emulsion was prepared Lit low pH. Complexes were found to dissociate when 0.1 or 0.5 M NaCl was present, suggesting that associative interactions between CN and DS are mainly clectrostatic. (c) 2007 Elsevier Ltd. All rights reserved.