The effect of irradiation on the functional properties of spray-dried egg white protein

The foaming properties of spray-dried egg white powder were examined as a function of dosage with ionizing radiation. Foam stability was studied by a micro-conductimetric method. A marked increase in foam stability was observed in all the irradiated samples examined (2–16 kGy) when compared to a non-irradiated control. The drainage rate and minimum thickness of air-suspended thin liquid films stabilised with egg white protein was measured interferometrically. The rate of film thinning decreased with increasing dose suggesting a dose related change in the bulk viscosity. There were minor changes in the secondary and tertiary structure of the irradiated protein determined by circular dichroism, which may account for the observed changes in functionality.