Title : Designing colloidal microstructures from plant biopolymers for rheology control and fat mimetics
We report on novel structured food colloids for emerging applications in designing healthy foods of the future. Water-in-water emulsions comprising colloidal suspensions of microgel particles have been recently created from plant polysaccharides via physical and enzymatic-induced crosslinks. Gelation kinetics were investigated via small-amplitude shear oscillation, and the elastohydrodynamic lubrication mechanism in oral-mimicking processing conditions described using tribilogical models. A reduced friction coefficient was measured due to entrainment of deformable microgel particles to the tribopair contact zone, similar to oil droplets in oil-in-water emulsions. A range of microgel particle structures and crosslinking densities were designed by controlling gelation kinetics and shear-induced break up during production, allowing the microstructure to be tuned to impart desired rheologies and thus textural properties.
Two distinct oil structuring approaches were also investigated using water-insoluble biopolymer fractions from pulse hulls: (i) increasing particle volume fraction (φ) and
(ii) addition of water to previously formed particle-in-oil dispersion at a constant φ. The particulate oil-continuous dispersions exhibited a viscosity increase as a function of φ, which was modelled using the Krieger-Dougherty equation. At values close to their maximum volume packing (φ ? 0.50), the dispersions displayed a solid-like behaviour; and an elastic material response was obtained by inducing capillary water bridges between the water-swelled particles, giving rise to a reversibly aggregated network.
In this talk, we will discuss novel structuring design principles for controlling bulk rheology and thin film lubrication using plant biopolymers. This comprehensive understanding opens new strategies for: (i) design of water-based colloidal particles with tunable (fat-like) textural attributes and (ii) control the assembly of insoluble plant fractions for structuring liquid oils, thereby creating fat mimetics without chemical gelators.