Laboratory of Food Proteins and Colloids, School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China.
Laboratory of Food Proteins and Colloids, School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou 510640, China; Overseas Expertise Introduction Center for Discipline Innovation of Food Nutrition and Human Health (111 Center), Guangzhou 510640, China; Department of Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China.
Food Res Int. 2021 Dec;150(Pt A):110733. doi: 10.1016/j.foodres.2021.110733. Epub 2021 Sep 30.
Novel supramolecular nanofibrils assembled from food-grade saponin glycyrrhizic acid (GA) are effective building blocks to make complex multiphase systems, e.g., emulsion foams. In this work, the effects of different oil phases (castor oil, sunflower oil, dodecane, and limonene) on the formation, stability and structural properties of long-lived emulsion foams prepared by GA nanofibrils (GNs) were investigated. The obtained results showed that soft-solid emulsion foams (4 wt% GNs) can be fabricated, independently of oil phase, and their structural properties, viscoelasticity, and tribological properties can be well tuned by oil phase polarity. Compared to the GNs aqueous foams, the presence of jammed emulsion droplets in the liquid channels and at the surfaces of bubbles can provide a higher bubble stability for emulsion foams. For more polar oil phase (castor oil), GNs showed a higher affinity to the oil-water interface with a lower interfacial tension, thus forming smaller oil droplets and bubbles, which leads to the higher mechanical strength, denser network microstructures, and lower friction coefficients of emulsion foams. However, the limonene foam exhibited weak storage stability and rheological properties, as well as the relatively low lubrication, which may be related to the formation of oil droplet aggregates and clusters induced by the volatility of limonene. GN-based emulsion foams are thermoresponsive, independently of oils, and the temperature-switchable process for the destabilization and regeneration of foams can be controlled and repeated. These emulsion foams based on natural saponin nanofibrils with tunable properties have potential sustainable applications in foods, pharmaceuticals, and personal care products.
由食品级皂苷甘草酸（GA）组装而成的新型超分子纳米纤维是构建复杂多相体系（如乳液泡沫）的有效构建块。在这项工作中，研究了不同油相（蓖麻油、葵花籽油、十二烷和柠檬烯）对 GA 纳米纤维（GNs）制备的长寿命乳液泡沫的形成、稳定性和结构性能的影响。结果表明，无论油相如何，都可以制备出软-固乳液泡沫（4wt%GNs），并且可以通过油相极性很好地调节其结构性能、粘弹性和摩擦学性能。与 GNs 水基泡沫相比，在液体通道和气泡表面存在被堵塞的乳液液滴，可以为乳液泡沫提供更高的气泡稳定性。对于更极性的油相（蓖麻油），GNs 对油水界面具有更高的亲和力，界面张力更低，因此形成更小的油滴和气泡，这导致乳液泡沫具有更高的机械强度、更密集的网络微观结构和更低的摩擦系数。然而，柠檬烯泡沫表现出较弱的储存稳定性和流变性能，以及相对较低的润滑性，这可能与柠檬烯的挥发性引起的油滴聚集和团聚有关。基于 GN 的乳液泡沫具有温度响应性，与油无关，并且可以控制和重复泡沫的失稳和再生的温度开关过程。这些具有可调性能的基于天然皂苷纳米纤维的乳液泡沫在食品、制药和个人护理产品中具有潜在的可持续应用。
