Rheology of oil-in-water emulsions stabilised by native cellulose microfibrils in primary plant cells dispersions

We have investigated the rheology of oil-in-water emulsions stabilised in a dispersion of cellulose microfibril – biopolymer hybrid networks. In these systems, Pickering-like stabilisation from individual CMFs and bundles is provided in combination with a viscoelastic fibrillar network that prevents the droplets from coalescing. The complex modulus of emulsions in such dispersions was measured for oil concentrations ranging from 5 to 50 wt%. Models for the complex modulus of a suspension of particles in a viscoelastic matrix are used to predict the modulus of such an emulsion for different oil and microfibril concentrations. It was found that introducing the effect of the influence of the dispersed phase on the deagglomeration of the CMF after a second homogenisation step allows for a good agreement with the experimental data for both models at high concentration of cellulose microfibrils. However, at moderate oil concentrations, the model overpredicts the complex modulus, as the presence of droplet clusters decreases the value of the measured modulus.