Fabrication of heat-stable composite microparticles from egg and whey proteins and their application in emulsion stabilization

This study investigated the feasibility of egg and whey proteins (WPI-EGG) mixture in developing heat-stable O/W emulsions at high concentrations of proteins (10%). Different pHs of 3, 4, 5, 6, and 7 were applied to fabricate heat-stable protein particles. The composite microparticles of WPI-EGG were prepared by heating at 95 °C for 10 min, followed by homogenization under sonication. Moderate pHs of 4–6 were appropriate for aggregate formation and particles whose size varies from 215 to 1333 nm. According to the results, particles generated at pH 5 and 6 showed the viscosity less than 1000 cp due to spherical morphology contrast to the mix of linear and spherical particles fabricated at pH 4 exhibiting viscosity higher than 2000 cp. The particles were characterized with hydrogen bonds and hydrophobic interactions. The lowest surface hydrophobicity was observed for particles prepared at pH 5. Although the greatest denaturation enthalpy and temperature were observed for particles of pH 6, those obtained at pH 5 were capable to form heat-stable emulsions with appropriate viscosity following thermal pasteurization. The increase of disordered random coil structures in the particles (pH 6) was found as main reason of the increased thermal stability at pH 6.