Viscous, flowable nanoemulsions stabilized with ionic emulsifier can be transformed into repulsively jammed elastic gels that do not flow under gravity by reducing the droplet size and increasing the interfacial repulsive shell layer thickness. However, a high concentration of emulsifier required to achieve nanodroplets could remain in the continuous phase and lead to oscillatory structural forces, thereby reducing repulsive interaction and forming flowable liquid systems. It was hypothesized that the removal of excess emulsifier from a nanoemulsion could lead to the formation of repulsive gels. Canola oil-in-water nanoemulsions, containing 40 wt % oil, were prepared with a citric acid ester of monoglyceride (Citrem) using a high-pressure homogenizer. The excess emulsifier in the aqueous phase was removed by multiple ultracentrifugation cycles, and the droplet size, rheology, and stability of the nanoemulsions were investigated as a function of excess Citrem concentration. Nanoemulsions with average droplet sizes of 222 and 150 nm were obtained with 3 and 5 wt % Citrem, respectively. The removal of excess Citrem did not change the droplet size significantly. However, the viscosity, yield stress, and storage moduli increased significantly with the reduction of excess Citrem and the decrease in droplet size, converting the flowable weak gel nanoemulsion to a strong viscoelastic gel. The calculated values of oscillatory structural forces decreased with the removal of excess emulsifier, leading to an increase in repulsive interactions and the thickness of the electric double layer. Such an increase in interdroplet separation led to an increase in the effective oil volume fraction beyond the maximum random jamming of oil droplets and the formation of a viscoelastic nanoemulsion gel.

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This research aimed to induce repulsive gelation in Citrem-stabilized O/W emulsions by creating a secondary layer of chitosan around the droplets. A range of chitosan concentration (0-0.25wt%) and degree of...

Summary Liquid nanoemulsions are shown to transform into viscoelastic gels by reducing droplet size, increasing interfacial repulsive barrier between the nanodroplets and therefore increasing the effective oil volume fraction. The repulsive gelation in nanoemulsions can be achieved at a significantly lower oil volume fraction compared to conventional emulsion gels, making the nanoemulsion gel an attractive material for various low‐fat food applications. Gelation in nanoemulsions stabilized by anionic small molecule emulsifier and polymeric protein are compared in terms of gel strength, average droplet size, effective oil volume fraction, and long‐term gel stability. It is expected that higher stability and large surface area of nanoscale droplet size can further extend the application of nanoemulsion gels in the field of functional foods, cosmetics and pharmaceuticals.

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