Viscosity of protein-stabilized emulsions: Contributions of components and development of a semipredictive model

Abstract

Protein-stabilised emulsions can be seen as mixtures of unadsorbed proteins and of protein-stabilised droplets. To identify the contributions of these two components to the overall viscosity of sodium caseinate o/w emulsions, the rheological behaviour of pure suspensions of proteins and droplets were characterised, and their properties used to model the behaviour of their mixtures. These materials are conveniently studied in the framework developed for soft colloids. Here, the use of viscosity models for the two types of pure suspensions facilitates the development of a semi-empirical model that relates the viscosity of protein-stabilised emulsions to their composition.

Rheology of protein-stabilised emulsion gels envisioned as composite networks 1– Comparison of pure droplet gels and protein gels

“…This indicates that over the range of concentrations studied, the dynamical behaviour of the gels is the same. By contrast, the viscosity of the suspensions increases dramatically over the same range of volume fraction, as discussed in a previous study [34]. The negligible variations of the frequency dependence of the gels seem to indicate that there is no change in regime due to the crowding of the colloidal particles in the solid state, and the gels formed by proteins and droplets suspensions are similar in that respect.…”

“…The first notable result is the similar properties of the two types of gels as a function of volume fraction φ ef f , derived from the viscosity of semidilute suspensions [34]. This result is significant, as the differences seen in the gel properties of proteins and protein stabilised emulsions that have been observed previously [40,12] are accounted for by a careful choice of the composition parameter.…”

“…[12]. Instead, we argue here that a more appropriate scaling to use for comparing protein gels and droplet gels is the volume fraction, despite its definition being non-trivial for complex colloidal particles [34].…”

Self‐Assembly of Nanoparticles in 2D and 3D: Recent Advances and Future Trends

“…Analytical solution of the time‐averaged Navier–Stokes equations elucidates the role of mean hydrodynamic flows and an overall balance of forces in governing the dynamic self‐assembly has been elucidated. Roullet et al have observed that the application of viscosity models for the two types of pure suspensions facilitates the development of a semi‐empirical model that relates the viscosity of protein‐stabilized emulsions to their composition.…”

Rheology of protein-stabilised emulsion gels envisioned as composite networks. 2 - Framework for the study of emulsion gels

“…The oil droplets are part of the network, as they exhibit an attractive interaction between them mediated by the adsorbed proteins at their interface. The protein-stabilised droplets and caseinate assemblies presented here have been thoroughly characterised in a previous study [31].…”