Properties and functions of stabilizing agents in food emulsions

Abstract

This review outlines the state of knowledge concerning the basic processes which underlie the behavior of food stabilizers in practical applications. The stability of emulsions is discussed in terms of the forces acting between macroscopic colloidal particles. These forces include the van der Waals force of attraction, which is always present, and the electrostatic, steric, and hydration forces which may stabilize an emulsion since they can be repulsive. The adsorption behavior at the liquid/liquid interface of classes of typical food stabilizers and the influence of the absorbed layer on the droplet-droplet interactions in emulsions are discussed. Finally, the important effects of the surface-active properties of stabilizers on the mechanisms involved in emulsion formation are described.

Effects of different oils on the properties of soy protein isolate emulsions and gels

“…This could explain the larger decrease in the emulsifying stability of the palm stearin emulsion at higher fat concentration. The results also indicate that ESI decreased in parallel with the protein to oil ratio, implying that stability of the emulsions decreased with decreasing protein concentrations, which agrees with Parker's (1987) explanation. Fig.…”

“…Sourdet, Relkin, and César (2003) reported formation of larger D 3,2 with decreasing protein concentrations for milk protein emulsions. Parker (1987) stated that, by increasing the concentration of proteins, a reduction in the interfacial tension of the droplets was facilitated, which resulted in their breakdown into smaller droplets.…”

Effect of salt content on the rheological properties of salad dressing-type emulsions stabilized by emulsifier blends

“…Interfacial films made with native granules usually present a lesser viscoelasticity than those made with constituents liberated from granules. Moreover, the effective reduction of interfacial tension during emulsification requires unfolding of adsorbed proteins at the interface to allow their non-polar segments to come into contact with the oil (Parker, 1987). Native granules are likely to have a poor efficiency to decrease interfacial tension because large particles evidently would not spread over the interface as individual proteins do.…”

Surface activity, film formation, and emulsifying properties of milk proteins

“…The forces involved in stabilizing and destabilizing emulsion include van der Waals attractive forces, electrostatic interaction, and steric factors related to the surface-active agents' osmotic effects, hydration forces, and viscosity of the continuous medium. 9 The stability of emulsions reflect an energy barrier to the close approach of individual droplets, the dynamics of which depend upon the combination of these forces. In most cases, the free energy of an emulsion is higher than that of respective liquid phases because of the energy associated with the large interfacial area of an emulsion.…”