Pickering Emulsions Stabilized by Protein Nanoparticles

Pickering emulsions represent a class of multiphase systems in which solid particles, rather than conventional surfactants, adsorb irreversibly at oil–water interfaces to impart kinetic stability. Protein nanoparticles have emerged as versatile stabilisers due to their biocompatibility, tunable surface properties and potential for sustainable sourcing. These particles can be engineered from plant or animal proteins via methods such as heat treatment, pH shifting or enzymatic hydrolysis, yielding sub-100 nm colloids that assemble at the interface and form elastic interfacial films. The wettability of the protein nanoparticle, as indicated by the three-phase contact angle, dictates droplet morphology and stability. Interfacial rheological characteristics and particle–particle interactions govern resistance to coalescence, flocculation and Ostwald ripening. Practical applications span food-grade delivery systems for lipophilic bioactives, nutraceutical carriers, cosmetic formulations and environmentally benign emulsions for pesticide or pharmaceutical delivery. The shift towards plant proteins and agro-industrial by-products underpins a drive for circular economy solutions, while advances in interfacial characterisation shed light on mechanisms of stabilisation and controlled release.

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Pickering Emulsions Stabilized by Protein Nanoparticles publication trend

The graph below shows the total number of articles in pickering emulsions stabilized by protein nanoparticles across all publications each year (not limited to Nature Index journals).

Technical terms

Pickering emulsion: An emulsion stabilised by solid particles adsorbed at the oil–water interface rather than by surfactant molecules.
Protein nanoparticle: Colloidal particles, typically under 100 nm, formed from proteins and used to stabilise emulsions through interfacial adsorption.
Three-phase contact angle: The angle at which a particle meets the oil, water and air phases, indicating its wettability and tendency to stabilise oil-in-water or water-in-oil emulsions.
Quartz crystal microbalance with dissipation (QCM-D): A technique that measures changes in frequency and energy dissipation of an oscillating crystal to quantify mass adsorption and viscoelastic properties of interfacial films.
Zeta potential: The electrostatic potential at the slipping plane of a colloidal particle, indicative of its propensity to repel neighbouring particles and resist aggregation.
Flocculation: The process by which dispersed droplets or particles aggregate loosely under attractive forces, influencing the rheology and stability of emulsions.

References

1. Properties of Heat-Assisted pH Shifting and Compounded Chitosan from Insoluble Rice Peptide Precipitate and Its Application in the Curcumin-Loaded Pickering Emulsions. Foods (2023).
2. Pickering Emulsion Stabilized by Tea Seed Cake Protein Nanoparticles as Lutein Carrier. Foods (2022).
3. Pickering Emulsions Stabilized by Tea Water-Insoluble Protein Nanoparticles From Tea Residues: Responsiveness to Ionic Strength. Frontiers in Nutrition (2022).