Department of Food Engineering (DEA), Faculty of Food Engineering (FEA), University of Campinas (UNICAMP), Rua Monteiro Lobato, 80; Campinas-SP; CEP, 13083-862, Brazil.
Department of Food Engineering (DEA), Faculty of Food Engineering (FEA), University of Campinas (UNICAMP), Rua Monteiro Lobato, 80; Campinas-SP; CEP, 13083-862, Brazil.
Food Res Int. 2019 Aug;122:252-262. doi: 10.1016/j.foodres.2019.04.028. Epub 2019 Apr 13.
Water-in-oil high internal phase emulsions (HIPEs) can provide interesting textures that could be used to reduce trans- and/or saturated fat content in food products. On the other hand oil-in-water emulsions can be found in a variety of food and beverages. Moreover, strategies aiming synthetic or semi-synthetic ingredients replacement by natural alternatives for food applications has been pursuit. For these purposes, the effect of partial replacement of PGPR by lecithin on properties of either W/O-HIPEs or O/W emulsions manufactured from the same initial composition but showing different volume fraction of dispersed phase were investigated aiming to understand the behaviour of emulsifiers' mixture in water-oil or oil-water interfaces. Firstly, water-in-oil HIPEs were produced using a rotor-stator device. At fixed total amount of emulsifier (2% w/w), W/O emulsions stabilized with LEC:PGPR ratios of 0.5:1.5 and 1.0:1.0 showed similar droplet size with a better kinetic stability compared to emulsions containing only PGPR. These results indicated good interaction between LEC and PGPR, which was also confirmed by dynamic interfacial tension profile and interfacial dilational rheology. In order to reduce the droplet size of W/O-HIPEs, these emulsions were subsequently subjected to high-pressure homogenization and interestingly phases inversion was observed. Confocal microscopy confirmed the phases inversion attributed to high input of energy leading to the formation of O/W emulsions. Then both W/O-HIPEs and O/W emulsions were investigated regarding LEC:PGPR mixtures as emulsifiers. All W/O-HIPEs showed shear thinning behavior and high viscosity at low shear rate whereas O/W emulsions showed low viscosity and Newtonian behavior. The increase of lecithin content in emulsifier mixture led to more stable O/W emulsions, whereas more stable W/O-HIPEs were produced by lecithin and PGPR mixtures ratio of 0.5:1.5 and 1.0:1.0.
油包水高内相比乳液（HIPEs）可以提供有趣的质地，可用于降低食品中反式和/或饱和脂肪的含量。另一方面，水包油乳液可以在各种食品和饮料中找到。此外，人们一直在追求用天然替代品替代合成或半合成成分的策略，以用于食品应用。出于这些目的，研究了部分用卵磷脂替代 PGPR 对由相同初始组成但分散相体积分数不同的 W/O-HIPEs 或 O/W 乳液的性质的影响，旨在了解乳化剂混合物在油水或油-水界面的行为。首先，使用转子-定子装置制备油包水 HIPEs。在固定的乳化剂总量（2%w/w）下，LEC:PGPR 比例为 0.5:1.5 和 1.0:1.0 的 W/O 乳液的粒径相似，与仅含有 PGPR 的乳液相比具有更好的动力学稳定性。这些结果表明 LEC 和 PGPR 之间存在良好的相互作用，这也得到了动态界面张力曲线和界面扩张流变学的证实。为了减小 W/O-HIPE 的粒径，随后将这些乳液进行高压匀质处理，有趣的是观察到相反转。共聚焦显微镜证实了相反转归因于高能量输入导致形成 O/W 乳液。然后研究了 W/O-HIPE 和 O/W 乳液作为乳化剂的 LEC:PGPR 混合物。所有 W/O-HIPE 都表现出剪切稀化行为和低剪切速率下的高粘度，而 O/W 乳液表现出低粘度和牛顿行为。乳化剂混合物中卵磷脂含量的增加导致更稳定的 O/W 乳液，而卵磷脂和 PGPR 混合物的比例为 0.5:1.5 和 1.0:1.0 时，可制备更稳定的 W/O-HIPE。
