The effect of the presence of KCl on the adsorption behaviour of whey protein and caseinate in oil-in-water emulsions
The effect of the presence of KCl on the adsorption behaviour of whey protein and caseinate in oil-in-water emulsions
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DOI：
10.1016/s0268-005x(96)80030-0
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发表时间：
1996-04-01
影响因子：
10.7
通讯作者：
Dalgleish, DG
中科院分区：
文献类型：
--
作者：
Hunt, JA;Dalgleish, DG
制备含有 20% 大豆油和 2% 蛋白质（酪蛋白酸盐或乳清分离蛋白 (WPI)）的乳液。在 pH 7 时，使用 WPI 制备的乳液中的油滴显示，随着 KCl 浓度在 0-200 mM 范围内的增加，其直径略有增加，但在 pH 3 时，KCl 浓度> 50 mmol/dm(3) 导致颗粒直径大幅增加，并且乳液呈现粘性。 KCl 的这种作用不会通过稀释而逆转。在用蛋白质混合物制备的乳液中，从 WPI 和酪蛋白酸盐吸附的蛋白质比例受到 KCl 存在的影响。这也反映在最初用 WPI 制成并随后重新悬浮在酪蛋白酸盐中的乳液液滴上吸附的蛋白质的组成中。在这些重悬乳液中，所有 α-乳清蛋白都被酪蛋白取代，并且被取代的 β-乳球蛋白的量取决于引入酪蛋白酸盐时 WPI 乳液的老化时间。吸附层的厚度取决于（i）用于制备乳液的蛋白质类型，以及（ii）均质后是否添加更多蛋白质，以及（iii）添加更多蛋白质时乳液的老化时间。这种行为反映了吸附层的不同结构。
Emulsions were prepared containing 20% soya oil and 2% protein, which was either caseinate or whey protein isolate (WPI). At pH 7 oil droplets in emulsions made using WPI showed small increases in the diameter with increasing concentration of KCl in the range 0-200 mM, but at pH 3 concentrations of KCl > 50 mmol/dm(3) caused very large increases in the diameters of the particles and the emulsions appeared viscous. This effect of KCl was not reversed by dilution. In emulsions prepared with mixtures of proteins, the proportions of proteins adsorbing from WPI and caseinate were affected by the presence of KCl. This was reflected also in the composition of adsorbed protein on emulsion droplets made originally with WPI, and subsequently resuspended in caseinate. In these resuspended emulsions all of the alpha-lactalbumin was displaced by caseins, and the amount of beta-lactoglobulin displaced depended on the age of the WPI emulsion when caseinate was introduced. The thickness of the adsorbed layer depended on (i) the type of protein that was used to make the emulsion, and (ii), whether more protein was added after homogenization and (iii), the age of the emulsion when further protein was added. This behaviour reflected different structures of the adsorbed layer.