Towards the development of a predictive model of the formulation-dependent mechanical behaviour of edible oil-based ethylcellulose oleogels

Abstract

The functionality of the recently discovered ethylcellulose (EC) oleogel systems are highly dependent on the mechanical strength of these gels. This mechanical strength depends strongly on a variety of different compositional parameters. Here we report on a predicative model relating the mechanical strength of EC oleogels as a function of both gelator and surfactant concentration for a variety of oils, surfactants, and EC molecular weights. Predictive modelling was based on a goodness-of-fit approach achieved in a step-wise fashion. Two-dimensional fits were performed on the experimental data for gel strength as a function of both mass fraction ethylcellulose (0.07–0.15) and surfactant (fixed to three EC/surfactant ratios) to obtain candidate equations for the eventual three-dimensional model. It was discovered that gel strength increases with mass fraction of EC in a power law fashion for all conditions tested. Comparison of mechanical strength determined by back extrusion and texture profile analysis (TPA) showed similar trends in scaling behaviour. In addition, the behaviour of the elastic constant extracted from TPA was also found to follow a power law with increasing gelator concentration. Finally, the validity of the predictive model was investigated through interpolation.