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

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Original languageEnglish
Pages (from-to)878-887
Number of pages10
JournalJournal of Colloid and Interface Science
Volume579
Early online date5 Jul 2020
DOIs
Publication statusE-pub ahead of print - 5 Jul 2020

Abstract

Hypothesis
Protein-stabilised emulsion gels can be studied in the theoretical frame-work of colloidal gels, because both protein assemblies and droplets may be considered as soft colloids. These particles differ in their nature, size and softness, and these differences may have an in uence on the rheological properties of the gels they form.
Experiments
Pure gels made of milk proteins (sodium caseinate), or of sub-micron protein-stabilised droplets, were prepared by slow acidiffication of suspensions at various concentrations. Their microstructure was characterised, their vis-coelasticity, both in the linear and non-linear regime, and their frequency dependence were measured, and the behaviour of the two types of gels was compared.
Findings
Protein gels and droplet gels were found to have broadly similar mi-crostructure and rheological properties when compared at fixed volume frac-tion, a parameter derived from the study of the viscosity of the suspensions formed by proteins and by droplets. The viscoelasticity displayed a power law behaviour in concentration, as did the storage modulus in frequency. Additionally, strain hardening was found to occur at low concentration. These behaviours diered slightly between protein gels and droplet gels, showing that some specic properties of the primary colloidal particles play a role in the development of the rheological properties of the gels.

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