Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada.
Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada.
Food Res Int. 2017 Sep;99(Pt 1):355-362. doi: 10.1016/j.foodres.2017.04.008. Epub 2017 Apr 18.
We show that the rigidity and microstructure of water-in-oil (W/O) emulsions depend on the ability of oil-soluble emulsifiers to enhance the crystallization of fats on the surface of dispersed aqueous droplets. In test emulsions consisting of hydrogenated soy oil (HSO) in liquid canola oil (CO) and a dispersed aqueous phase representing up to 20wt% of the emulsion, use of glycerol monooleate (GMO) promoted oil-water interfacial crystallization whereas polyglycerol polyricinoleate (PGPR) resulted in HSO crystallization in the continuous phase only. By removing the confounding effects of droplet size and solid fat content, GMO-covered emulsion droplets were shown to behave as active fillers as they interacted with the surrounding fat crystal matrix and increased emulsion rigidity. By contrast, the PGPR-stabilized droplets only weakly associated with the matrix and did not significantly alter emulsion rheology, hence these were inactive fillers. This study shows that by simply changing emulsifier type, it is possible to alter the magnitude of the association between the dispersed droplets and surrounding fat crystals and, by extension, tailor the texture and rigidity of fat crystal-stabilized water-in-oil emulsions.
我们表明，油包水乳状液的刚性和微观结构取决于油溶性乳化剂增强脂肪在分散的水相液滴表面结晶的能力。在由氢化大豆油（HSO）在液体菜籽油（CO）和占乳液高达 20wt%的分散水相组成的测试乳液中，使用甘油单油酸酯（GMO）促进油水界面结晶，而聚甘油蓖麻醇酸酯（PGPR）则导致 HSO 仅在连续相中结晶。通过消除液滴大小和固体脂肪含量的混杂影响，显示出 GMO 覆盖的乳液液滴作为活性填料与周围的脂肪晶体基质相互作用并增加乳液刚性。相比之下，PGPR 稳定的液滴仅与基质弱相互作用，并且不会显著改变乳液流变学，因此它们是不活跃的填料。本研究表明，通过简单地改变乳化剂类型，有可能改变分散液滴与周围脂肪晶体之间的结合程度，并由此调整脂肪晶体稳定的水包油乳液的质地和刚性。
