Water-in-Oil Pickering Emulsions Stabilized by Synergistic Particle–Particle Interactions

Abstract

Here, we report a novel “double Pickering stabilization” of water-in-oil (W/O) emulsions, where complex formation at the interface between Pickering polyphenol particles adsorbing from the oil side and whey protein microgel (WPM) particles coadsorbing from the aqueous side of the interface is investigated. The interfacial complex formation was strongly dependent on the concentration of WPM particles. At low WPM concentrations, both polyphenol crystals and WPM particles are present at the interface and the water droplets were stabilized through their synergistic action, while at higher concentrations, the WPM particles acted as “colloidal glue” between the water droplets and polyphenol crystals, enhancing the water droplet stability for more than 90 days and prevented coalescence. Via this mechanism, the addition of WPM up to 1 wt % gave a significant improvement in the stability of the W/O emulsions, allowing an increase to a 20 wt % water droplet fraction. The evidence suggests that the complex was probably formed due to electrostatic attraction between oppositely charged polyphenol Pickering particles on the oil side of the interface and WPM Pickering particles mainly on the aqueous side of the interface. Interfacial shear viscosity measurements and monolayer (Langmuir trough) experiments at the air–water interface provided further evidence of this strengthening of the film due to the synergistic particle–particle complex formation at the interface.

New Insights into the Formulation and Polymerization of Pickering Emulsions Stabilized by Natural Organic Particles

“…However, applying the adapted process in the right pH conditions they can self-assemble into particulate shape to act as Pickering emulsifiers. Hence, both plant-based (soy ,, and zein) and animal-based (casein, whey, , lactoglobulin, and BSA , ) protein particles were efficiently used to stabilize both O/W and W/O emulsions. Often, proteins are used in synergy with polysaccharides under the form of complexes .…”

Conjugate microgel-stabilized Pickering emulsions: Role in delaying gastric digestion

“…Interfacial shear viscosity experiments can give powerful insights into structural characteristics of the adsorbed layer, and relate the interfacial properties to aspects of the formation and stability of the emulsion (Murray, Durga, Yusoff, & Stoyanov, 2011;Zembyla, Lazidis, Murray, & Sarkar, 2019;Zembyla, Murray, Radford, & Sarkar, 2019). Figure 6c shows the time-dependent shear viscosity data of adsorbed films of WPN (used as control) (Araiza-Calahorra, et al, 2019b) and WPDx10M particles at the n-tetradecane-water interface (0.5 wt%, pH 7.0, 25°C).…”

Recent Developments in the Formulation and Use of Polymers and Particles of Plant‐based Origin for Emulsion Stabilizations

“…Natural‐based polymers, such as proteins [24,25] or macromolecules like starch and lignin, are polymers with a strong affinity for one of the phases (i. e., soluble in one phase) and can bring electrostatic and steric repulsion or both to oil droplets [26,27] . The emulsions formulated using the above emulsifiers are called non‐Pickering or conventional emulsions.…”