Aquafaba as an egg white substitute in food foams and emulsions: Protein composition and functional behavior

The ability of aquafaba to act as an egg white substitute was tested as effect of change in the level of pH and conductivity of aquafaba. The properties of aquafaba and egg white were analyzed by protein composition, dry matter content and protein concentration. Moreover, the zeta potential of aquafaba was analyzed. Foaming properties were studied by a hand shaken foam test. Emulsions were prepared by mixing either egg white or aquafaba with sunflower oil. Foam produced by either aquafaba or egg white showed distinct properties in foam capacity, foam volume and the liquid ratio in foam as function of time. However, the test of liquid drainage as function of time showed no difference between the two protein sources. Test of emulsifying properties showed more stable emulsions produced by centrifugated aquafaba compared to egg-while based emulsions. The measurements of emulsion stability were based on UV absorbance, emulsion particle size as well as rheological analyses. Aquafaba properties were not affected by increased level of NaCl in the foam and emulsifying tests conducted, however, changes in the level of pH affected all tests with exception of the foam capacity. The stability of emulsions based on aquafaba increased with increasing pH level evaluated by UV-absorbance and emulsion particle size opposite to the yield stress (Pa), which in general decreased with increasing pH level.