The effects of low-molecular-weight emulsifiers in O/W-emulsions on microviscosity of non-solidified oil in fat globules and the mobility of emulsifiers at the globule surfaces.
The effects of low-molecular-weight emulsifiers in O/W-emulsions on microviscosity of non-solidified oil in fat globules and the mobility of emulsifiers at the globule surfaces.
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DOI：
10.1016/j.jcis.2013.12.036
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发表时间：
2014-04
影响因子：
9.9
通讯作者：
M. B. Munk;Henriette R. Erichsen;M. Andersen
中科院分区：
文献类型：
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作者：
M. B. Munk;Henriette R. Erichsen;M. Andersen
电子自旋共振谱（ESR）用于测量自旋探针克里思在O/W-乳液中的迁移率。这允许测定脂质球中液体部分的温度依赖性微粘度。研究了六种氢化棕榈仁油（HPKO）基乳状液，其含有酪蛋白酸盐和乳酸单甘油酯（LACTEM）、不饱和单甘油酯（GMU）或饱和单甘油酯（GMS）的不同组合。用LACTEM + GMU制备的乳液中的非固化油具有高的微粘度，而用GMS制备的乳液具有低的微粘度。此外，克里思在脂质和水相之间的分配被发现是高度温度依赖性的，最有可能是由于固体脂肪含量随温度的变化。这种行为可以模拟乳液中芳香化合物的分配。使用自旋探针5-doxylstearic acid来研究组分在脂质球表面的流动性。在5 °C下，所有乳液具有非常低的表面迁移率。在25 °C下，发现自旋探针的迁移率与表面蛋白质负载相关。具有GMU的乳液具有高蛋白质表面覆盖率和液滴表面上自旋探针的低迁移率。相反，在LACTEM和GMS的存在下，蛋白质表面负载降低，并观察到高的表面迁移率。基于这些结果，认为含有GMU的乳剂的高宏观粘度和脂质团聚是由于脂质球蛋白网络，其中脂质球通过酪蛋白酸盐连接。
Electron Spin Resonance spectroscopy (ESR) was used to measure the mobility of the spin probe TEMPO in O/W-emulsions. This allowed determination of temperature-dependent microviscosity of the liquid fraction in lipid globules. Six hydrogenated palm kernel oil (HPKO) based emulsions containing caseinate and different combinations of lactic acid ester of monoglyceride (LACTEM), unsaturated monoglycerides (GMU) or saturated monoglyceride (GMS) were studied. The non-solidified oil in emulsions made with LACTEM + GMU had a high microviscosity, whereas the emulsion made with GMS had a low microviscosity. Also the partitioning of TEMPO between the lipid and aqueous phases was found to be highly temperature dependent, most likely due to the change of solid fat content with temperature. This behaviour may mimic the partitioning of aroma compounds in emulsions. The spin probe 5-doxylstearic acid was used to study the mobility of the components at the lipid globule surfaces. At 5 °C all emulsions had a very low surface mobility. At 25 °C the mobility of the spin probe was found to be correlated to the surface protein load. Emulsions with GMU had a high protein surface coverage and low mobility of the spin probe on the droplet surfaces. Conversely, in presence of LACTEM and GMS, the protein surface loads decreased and high surface mobilities were observed. Based on these results it is argued that the high macroscopic viscosity and lipid agglomeration of emulsions containing GMU is due to a lipid globule–protein-network where the lipid globules are connected via caseinate.