Controlling textural attributes of plant-based emulsions using heteroaggregation of cationic and anionic potato protein-coated oil droplets

There is a need for semi-solid food matrices constructed from plant-derived ingredients to formulate plant-based foods, like egg, cheese, meat, and mayonnaise analogs. This study showed that heteroaggregation could be used to create plant-based semi-solid matrices by blending cationic and anionic droplets together. Heteroaggregation was induced by mixing 10 wt% olive oil-in-water emulsions containing either cationic potato protein-coated oil droplets (PPI300E) or anionic potato protein-coated oil droplets (PPI200E). Extensive droplet aggregation occurred at intermediate mixing ratios (25-75 wt%) because of electrostatic attraction between the oppositely charged oil droplets. Heteroaggregation led to a large increase in shear viscosity and elastic modulus, which was attributed to the formation of a network of protein-coated oil droplets held together by electrostatic attraction. The highest viscosity and elastic modulus were observed in the emulsions containing 75 wt% PPI200E and 25 wt % PPI300E. When the mixed emulsions were heated from 25 to 90 degrees C and then cooled back to 25 degrees C, there were pronounced changes in their rheological properties. The shear modulus of the mixed emulsions tended to increase when they were heated above their thermal denaturation temperature, which was attributed to strengthening of hydrophobic attractions between the droplets. In contrast, the shear modulus tended to decrease steeply during cooling, which suggested that the network of aggregated oil droplets partially collapsed. Rearrangement and consolidation of the oil droplets in the particle network during storage led to gravitational separation. Our results show that semi-solid emulsified foods can be formed from plant-derived ingredients using relatively low concentrations of protein and oil using heteroaggregation. These emulsions may be useful as structuring agents in some plant-based foods.