Thermal-assisted stirring as a new method for manufacturing o/w emulsions stabilized by gelatin-arginine complexes

Effects of pH (5, 7, or 9) and arginine level (0, 0.6%, 1.2%, or 1.8%, w/v) on the stabilization of emulsions prepared by a novel thermal-assisted stirring method were evaluated. The results of physical stability showed that thermal-assisted stirring was effective in manufacturing heat-insensitive o/w emulsions. As the arginine level increased, the emulsifying ability and the absolute zeta potential of each pH-treated group first increased significantly and then decreased significantly, reaching a maximum at 1.2% (w/v) addition. When pH increased, the emulsifying ability and the absolute zeta potential of each arginine-treated group increased significantly. The results of particle size, storage modulus, and loss modulus were in accordance with changes in the emulsifying ability and the zeta potential, which were confirmed by the microstructure. As a result, the emulsion prepared at pH 9 with 1.2% (w/v) arginine had the largest levels of emulsion stability and surface protein load (145.69 mg/m2). In conclusion, the major reason for the formation of heat-insensitive emulsions by thermal-assisted stirring might be attributed to a high level of surface protein load, and increasing pH and arginine addition might enhance the adsorption of gelatin-arginine complexes on the surface of oil droplets, thereby improving the stability of emulsions.