Emulsions Stabilization and Lipid Digestion Profiles of Sodium Alginate Microgels: Effect of the Crosslink Density

In this research, microgels with different crosslink density were prepared using the hydrophilic sodium alginate (ALG), and the interfacial adsorption, emulsion formation and lipid digestion profiles of these microgels were comparatively analyzed. Results showed that the microgels with different crosslink density exhibited different hardness, particle size, and surface hydrophobicity, but similar interfacial tension. The ALG microgels could stabilize an oil-in-water emulsion through the "Mickering mechanisms", that the particle size and hardness of the microgels have strong effects on their emulsifying behaviors, while the effects from surface hydrophobicity and interfacial tension were unconspicuous. A temperate crosslink density (e. g. 3 mM to 5 mM Ca2+) was benefit to the emulsifying capacity of the microgels at neutral (pH 7.0) and acidic (pH 4.0) environments. Moreover, the temperately crosslinked microgels stabilized oil droplets were more resistant to the displacement of bile salt and the followed lipid digestion. Our results provided important information for the development of polysaccharide-based food emulsifiers.