Charge density of carboxymethyl cellulose affects depletion attraction-stabilized egg yolk Pickering emulsion gels: Rheological and interfacial properties

The depletion attraction is critical for emulsion gel stabilization, but there are fewer studies and inconsistencies in high concentration emulsion gel systems. In this study, carboxymethyl cellulose (CMC) with different charge densities was used to induce depletion to stabilize highly concentrated emulsion gels. The results showed that the depletion of CMC with a high charge density enhanced emulsion gel stabilization. A low-charge-density CMC exhibited a lower depletion force and a wider depletion force weakened in the medium-depletion region. In addition, depletion attraction was divided into three stages with increasing CMC ratio: enhanced interfacial adsorption in the low depletion region, reduced depletion intensity in the medium depletion region, and strong depletion attraction in the high depletion region. The strength and stability of the emulsion gels with NaCl increase with increasing depletion agent concentration. CMC1.2-stabilized emulsion gels exhibit better rheological properties, such as high viscosity, viscoelasticity, shear sensitivity and stress. Especially for the low depletion region, CMC1.2 exhibited viscosity (261 Pa s), G′ value, and stress close to those of the high depletion region. Furthermore, CMC1.2 exhibited greater diffusion (Kd × 102: 158.94 ± 0.67 mN/m/s1/2), permeation and recombination interfacial properties. These findings provide a theoretical basis for stabilizing highly concentrated emulsion gel systems. [Display omitted] •High charge density induces greater depletion attraction.•The medium depletion region showed reduced depletion attraction.•CMC1.2 exhibited strong depletion attraction in the low depletion region.•Effect of depletion attraction in concentrated emulsion systems was illustrated.