Lutz Rachel, Aserin Abraham, Wicker Louise, Garti Nissim
Casali Institute of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Colloids Surf B Biointerfaces. 2009 Nov 1;74(1):178-85. doi: 10.1016/j.colsurfb.2009.07.014. Epub 2009 Jul 21.
W/O/W double emulsions (DEs) stabilized by charged soluble complexes of whey protein isolate (WPI) and modified pectins were investigated in relation to their stability and the release of two types of electrolytes, NaCl and sodium ascorbate. WPI alone cannot properly stabilize the DEs. The droplet size is relatively large (100 microm) and increases with time. However, addition of modified pectin to form a soluble complex with WPI significantly improved the stability. DEs prepared with two types of oils (medium chain triglycerides (MCT) and R(+)-limonene) were studied by measuring droplet size, creaming, viscosity, and electrolyte release. Irrespective of their very different oil phase nature, both emulsions were stable against coalescence, but R(+)-limonene formed smaller droplets (25 microm) than MCT (35 microm). The electrolyte release rate was significantly higher from the R(+)-limonene that formed DEs with much lower viscosity. R(+)-limonene-DE released 75% of the NaCl after 28 days, while MCT-DE released only 50%. NaCl was released more slowly than sodium ascorbate. Apparently, the release mechanism from R(+)-limonene-DE was found to be "thinning the outer interface and release of the entire inner droplets" while it seems that the release from MCT-DE was slower and "diffusion controlled". DEs stabilized by WPI/C63 released 12% of the sodium ascorbate after 1 day in milk and remained stable for at least 8 days. However, DEs stabilized with only WPI released about 50% of the sodium ascorbate after 1 day, and phase separated after 8 days.
研究了由乳清分离蛋白（WPI）和改性果胶的带电可溶性复合物稳定的水包油包水型双重乳液（DEs）的稳定性以及两种电解质（NaCl和抗坏血酸钠）的释放情况。单独的WPI不能很好地稳定DEs。液滴尺寸相对较大（100微米）且随时间增加。然而，添加改性果胶与WPI形成可溶性复合物显著提高了稳定性。通过测量液滴尺寸、乳析、粘度和电解质释放，研究了用两种油（中链甘油三酯（MCT）和R（+）-柠檬烯）制备的DEs。无论它们的油相性质有很大差异，两种乳液都能抵抗聚结，但R（+）-柠檬烯形成的液滴（25微米）比MCT（35微米）小。由粘度低得多的R（+）-柠檬烯形成的DEs的电解质释放速率明显更高。R（+）-柠檬烯-DE在28天后释放了75%的NaCl，而MCT-DE仅释放了50%。NaCl的释放比抗坏血酸钠慢。显然，发现R（+）-柠檬烯-DE的释放机制是“使外部界面变薄并释放整个内部液滴”，而MCT-DE的释放似乎较慢且是“扩散控制”的。由WPI/C63稳定的DEs在牛奶中1天后释放了12%的抗坏血酸钠，并至少稳定8天。然而，仅由WPI稳定的DEs在1天后释放了约50%的抗坏血酸钠，并在8天后发生相分离。
