Emulsion Stabilization Techniques in Food Systems

Emulsions—mixtures of two immiscible liquids such as oil and water—are ubiquitous in foods ranging from dressings and beverages to creams and sauces. Stabilisation of these systems relies on preventing droplet coalescence, creaming and flocculation throughout processing and storage. Traditional approaches employ low-molecular-weight surfactants or biopolymers such as proteins and polysaccharides to adsorb at the oil–water interface, lowering interfacial tension and forming protective layers around droplets. More recent strategies exploit particle-stabilised or Pickering emulsions, in which edible micro- or nanoparticles irreversibly attach to interfaces, creating steric and electrostatic barriers to droplet aggregation. Advanced methods also combine proteins and polysaccharides to form complex coacervates or interfacial gels, afford enhanced rheological control and tailor functionality for targeted release of bioactive compounds. High-pressure homogenisation, ultrasound and microfluidisation techniques refine droplet size distributions, further enhancing stability. These innovations underpin the development of low-fat formulations, improved shelf-life and encapsulation of sensitive nutrients, with global significance for healthier, more sustainable food products.

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Recent work has highlighted the potential of food-grade particles to stabilise Pickering emulsions with exceptional resistance to coalescence. A comprehensive review of diverse edible particles demonstrates how cellulose crystals, protein microgels and lipid-based colloids adhere strongly at interfaces, directing droplet packing and jamming mechanisms that inhibit creaming and ensure long-term stability. Applications range from nutrient delivery vehicles to low-fat spreads with tunable texture.

Studies on soy-protein-isolate and sodium alginate microparticles formed by pH-induced self-assembly reveal that electrostatic interactions produce stable complexes with uniform size and enhanced thermal resistance. These microparticles form robust interfacial layers around oil droplets, significantly improving emulsion viscosity and preventing coalescence under acidic and alkaline conditions, thereby expanding their use in acidic beverages and dairy analogues.

Investigations into whey protein isolate and heat-induced whey protein aggregates demonstrate how controlled aggregation affects interfacial layer viscoelasticity. At low protein concentrations, monomeric proteins yield fine droplets and rapid adsorption, while aggregates impart thicker, more elastic films at higher concentrations, optimising creaming stability in whipped creams and recombined dairy products. These findings inform selection of protein forms to match specific processing stresses and textural targets.

Emulsion Stabilization Techniques in Food Systems publication trend

The graph below shows the total number of articles in emulsion stabilization techniques in food systems across all publications each year (not limited to Nature Index journals).

Technical terms

Emulsion: A dispersion of one liquid phase as droplets within another immiscible liquid phase, typically oil-in-water or water-in-oil.

Pickering emulsion: An emulsion stabilised by solid particles that adsorb at droplet interfaces, forming a physical barrier to coalescence.

Surfactant: A surface-active agent that lowers interfacial tension between oil and water, promoting droplet formation and stability.

Interfacial tension: The force per unit length existing at the boundary between two immiscible phases, influencing droplet size and stability.

ζ-potential: The electric potential at the slipping plane of a particle or droplet, indicative of electrostatic stabilisation against aggregation.

References

1. Bulk and interfacial properties of milk fat emulsions stabilized by whey protein isolate and whey protein aggregates. Food Hydrocolloids (2020).
2. Recent Advances on Pickering Emulsions Stabilized by Diverse Edible Particles: Stability Mechanism and Applications. Frontiers in Nutrition (2022).
3. Soy Protein Isolate/Sodium Alginate Microparticles under Different pH Conditions: Formation Mechanism and Physicochemical Properties. Foods (2022).