Effect of pH on Physicochemical Properties of Egg Yolk-Sodium Alginate Emulsion Cold-Set Gel and Its Mechanism Analysis
Emulsion cold-set gel shows tremendous advantages and broad application prospects due to its unique structure and functional properties.With egg yolk protein(EYP)and sodium alginate(SA)as the substrates,an O/W type EYP-SA emulsion cold-set gel is formed by mixing with sunflower seed oil through high-speed shear homogenizer(oil phase:water phase is 3:7).The thermal stability,moisture distribution,rheology,solubility,surface hydrophobicity,intermolecular force and secondary structure of EYP-SA are analyzed by changing the pH of EYP-SA,and the effect and mechanism of pH on the physicochemical properties of EYP-SA emulsion cold-set gel are explored.The results show that pH significantly influences the properties of EYP-SA emulsion cold-set gel.With the increase of pH,the water-binding ability of EYP-SA is enhanced,and a uniform and dense network structure is gradually formed,showing good thermal stability.In the frequency scanning test,the increase of pH reduces the G'and G"of the sample,and the elasticity and rigidity of EYP-SA decrease.Solubility is significantly correlated with surface hydrophobicity,which may be due to the increase of pH,the increase of electrostatic repulsion force leading to the depolymerization of egg yolk particles.With the increase of solubility,the protein structure unfolds,exposing the hydrophobic groups originally embedded in the protein molecules to the surface of the protein molecules.Hydrophobic interaction and hydrogen bonding are the main molecular forces in the formation of EYP-SA emulsion cold-set gel.When pH is 9.0,the droplets in EYP-SA emulsion are small and uniformly dispersed,which is more conducive to the encapsulation of substances.These findings have provided an important theoretical basis for the application of EYP-SA emulsion cold-set gel in food gel delivery systems.
万方数据
维普
