Recent advances in the stabilization of emulsions and foams by particles of nanoscale and microscopic dimensions are described. Ongoing research in this highly active field is providing insight into (i) the molecular factors controlling particle wettability and adsorption, (ii) the structural and mechanical properties of particle-laden liquid interfaces, and (ii) the stabilization mechanisms of particle-coated droplets and bubbles. There is much potential for exploiting the emerging knowledge in new food product applications. The preparation of cheap and effective colloidal particles based on food-grade ingredients, especially proteins, is the key technological challenge.

Food emulsions and foams: Stabilization by particles

Protein/polysaccharide complexes and coacervates in food systems

Improving emulsion formation, stability and performance using mixed emulsifiers: A review.

The exploitation of protein–polysaccharide interactions offers opportunities for the design of new ingredients and interfacial structures with applications in the food and pharmaceutical industries. Association of protein and polysaccharide molecules may occur chemically through covalent bonds or physically through electrostatic interactions. Theoretical and experimental studies indicate that various molecular and thermodynamic factors can be adjusted to optimize the effectiveness of covalent conjugates and electrostatic complexes in the stabilization of interfaces, gels and emulsions. Maillard-type protein–polysaccharide conjugates have excellent emulsifying and steric stabilizing properties, especially under conditions where the protein alone is poorly soluble. Charged polysaccharides form soluble complexes or coacervates with proteins depending on pH, ionic strength, and biopolymer charge distribution. The structure and stabilizing properties of the mixed protein + polysaccharide layer depends on the sequence of adsorption of the biopolymers to the interface. There is good potential for use of interfacial protein–polysaccharide complexes in the nanoscale engineering of delivery vehicles for nutrient encapsulation and in the protection of adsorbed proteins and emulsified lipids against enzymatic breakdown during digestion.

Interfacial structure and stability of food emulsions as affected by protein–polysaccharide interactions

Solid particles of nanoscale and microscale dimensions are becoming recognized for their potential application in the formulation of novel dispersed systems containing emulsified oil or water droplets. This review describes developments in the formation and properties of food-grade emulsion systems based on traditional edible dispersed particles (fat crystals), commercial nanoparticles (silica nanoparticles), and novel particles of biological origin (starch microparticles, chitin nanocrystals). The special features characterizing the properties of particle-stabilized droplets are highlighted in comparison with those of conventional protein-stabilized emulsions. Complexities arising from synergistic interactions of particles with other surface-active ingredients are discussed.

Use of nanoparticles and microparticles in the formation and stabilization of food emulsions

Abstract Recent advances on protein–polysaccharide electrostatic complex and coacervates' formation, structure and properties are presented. The first section emphasises on the thermodynamics of complexes formation, the contribution of enthalpic and entropic effects is specifically discussed. Then, their structure is described at different length scales and recent findings on the phase-ordering dynamics of complex and coacervates formation are covered. Finally, the most relevant functional properties of protein–polysaccharide complexes and coacervates for food applications are described.

L. Aberkane

Papers

Protein-polysaccharide complexes and coacervates.