This paper presents a theoretical model to describe liquid drainage of foams prepared from egg white powder with added an additive while reflecting the validity of the model. Having utilized some simplifying assumptions in the non-linear partial differential equation of the foam drainage, an analytical solution for free drainage was obtained. To compare the results of the theoretical model and the experimental approach, a number of experiments were conducted in order to measure the drainage of foams prepared from egg white powder with added sugar (10% and 30%), xanthan gum (0.01% and 0.05%) and Chubak extract (0.01% and 0.05%). First, an analysis was performed on the physical properties of the solutions, i.e. density, viscosity and surface tension so that the influence of the additive’s presence would be examined. Moreover, the image analysis was applied to allow the assessment of the initial bubble size distributions. The experimental and theoretical drainage curves of different foams showed that foam drainage rate decreased due to the influences of the above-mentioned additives. According to the obtained results, the mathematical model can be adopted to estimate foam drainage rate.

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