pH-shifting treatment improved the emulsifying ability of gelatin under low-energy emulsification

The effects of pH-shifting treatments (pH 3, 5, 7, 9, and 11) on the stability of gelatin emulsions made by low-energy stirring were investigated. pH-shifting treatments significantly enhanced the ESI and EAI of the emulsion ( P  < 0.05) and reduced its particle size ( P  < 0.05) under low-energy emulsifying conditions. The pH 11 – 7 shifting treatment significantly increased the degree of depolymerization and the level of ordered structure of gelatin ( P  < 0.05). These transformations resulted in a significant increase in the exposure of hydrophobic and negatively charged residues ( P  < 0.05) on the surface of gelatin, facilitating a faster adsorption rate of gelatin onto the oil-water interface as well as an increase in the amount of gelatin adsorbed at the interface. Moreover, the alkali-shifting treatment promoted the formation of a thin viscoelastic interfacial film, which contributed to the enhanced stability of the emulsion.