Interfacial,Emulsifying And Digestion Properties Of Sodium Alginate Microgels

The Mickering interface formed by deformable soft particles has a completely different stabilization mechanism.Compared with the Pickering interface,it has wider material selectivity and more flexible environmental response characteristics.At present,the interface and emulsification properties of Mickering particles prepared based on edible materials are rarely studied.In this paper,hydrophilic sodium alginate was used to prepare microgels with different crosslinking densities,and the basic physical and chemical properties of the microgels were characterized.On this basis,the interface adsorption,emulsion formation and lipid digestion behaviors of these microgels were systematically studied.The main results are as follows:1.Sodium alginate microgel can be adsorbed on the oil-water interface without presence of any other surfactants through the"Mickering"mechanism,and form a stable O/W emulsion.The concentration of sodium alginate has no obvious effect on the surface hydrophobicity and interfacial tension of the microgel,but has a significant effect on the surface charge,hardness and emulsification behavior.The emulsification behavior of sodium alginate microgel is not directly related to its interfacial tension,but has obvious correlation with its particle size and hardness.The smaller the microgel,the better the emulsion formation.The emulsion formed by the softer microgel has better p H stability,while the emulsion formed by the harder microgel has better salt tolerance.2.As the crosslinking density increases,the particle size of the sodium alginate microgel tends to be uniform,while the average particle size increases.The increase in crosslink density leads to a corresponding increase in the hardness and surface hydrophobicity of the microgel,while the surface charge and interfacial tension remain unchanged.The surface hydrophobicity and interfacial tension of sodium alginate microgel have no obvious influence on its emulsification behavior,but the particle size and hardness have obvious influence.The smaller the particle size of the microgel,the lower the hardness,which is more conducive to emulsion formation.Under suitable crosslinking density,the emulsion formed by sodium alginate microgel has better p H stability and salt tolerance.3.The cross-linking density of the sodium alginate microgel has a significant effect on the lipid digestion behavior of the emulsion.The interface formed by sodium alginate microgel with moderate cross-linking density(such as Ca²⁺content of 3 m M～5m M)can effectively inhibit the adsorption of bile salts and lipase on the surface of the emulsion,and further inhibit the digestion of fat.The excessively high crosslinking density(10 m M～50 m M Ca²⁺)makes the sodium alginate microgel on the surface of the emulsion droplets easily replaced by bile salts,which leads to fat hydrolysis.