Modulation of stability, rheological properties, and microstructure of heteroaggregated emulsion: Influence of oil content

Abstract The impact of oil content on the stability, shear rheology, microrheology and microstructure of heteroaggregated emulsions with 40% whey protein isolate (WPI)-coated droplets and 60% flaxseed gum (FG)-coated droplets at pH 3.0 was studied. The mean particle size, zeta-potential, physical stability, the mean square displacement (MSD), solid liquid balance (SLB), viscosity and Cryo-SEM microstructure of the heteroaggregated emulsions as a function of oil contents ranging from 10% to 30% were measured. It was found that the physical stability and viscosity of the heteroaggregated emulsion was decreased with increasing oil content. MSD curves showed that the particle motion of heteroaggregated emulsions with increasing oil contents was obviously accelerated at a shorter decorrelation time, which indicated that elastic behavior would be dominated with higher oil content (20% & 30%). Cryo-SEM microstructure proved that the specific three-dimensional network of the heteroaggregated emulsion could be formed at low oil content (10% & 15%) by the strong electrostatic and steric interactions between droplets and free WPI and FG. It proved that heteroaggregates formed by WPI-coated droplets and FG-coated droplets may be useful for creating specific food structures that lead to desirable viscosity at low fat content.