Oleogels prepared from polysaccharide-stabilized aqueous foams: synergistic effect of gum mixtures

Several food-grade polysaccharides exhibit interfacial activity in water, influencing their foaming ability by modulating surface tension, film elasticity, and viscosity, which collectively impact foam stability and structure. Oleogels play a crucial role in structuring liquid oils without trans fats, and their sustainable preparation using oil-adsorbing cryogels derived from aqueous polysaccharide foams offers an eco-friendly and low-cost approach to developing healthier and functional fat replacers. In this sense, this study aimed to investigate the foaming properties of aqueous solutions containing methyl cellulose (MC) mixed with different edible gums, named xanthan gum, gellan gum, Locust bean gum, tara gum, and kappa carrageenan, and their use as templates to obtain cryogels, which were subsequently used to prepare oleogels with sunflower oil. The obtained results indicated that aqueous solutions with relatively low MC concentrations (below 0.1 wt.%) present good foaming ability and that xanthan and gellan gums were the ones that most contributed to foam stability. Such an enhanced stability was more dependent on the formation of highly viscoelastic surface films covering the air bubbles than on a highly viscous aqueous continuous phase. Foams with the highest stability were freeze-dried to obtain highly porous cryogels, which were characterized by scanning electron microscopy (SEM). SEM images indicated the formation of materials with porosity and surface roughness controlled by the polysaccharide nature. These cryogels presented a good ability to adsorb sunflower oil, thus giving rise to oleogels whose rheological properties will be further investigated. Collectively, the results indicate the feasibility of using polysaccharide-based foams as alternatives to produce fat replacers in food formulations.