Effect of two gums on the development, rheological properties and stability of egg albumen foams

Egg albumen foams (8%) with and without added propylene glycol alginate or xanthan gum (both at 0.2% concentration on wet weight basis) formed after 1-5 min whipping were tested for their consistency using squeezing flow viscometry and stability. The apparent stress at two specimen heights (1.5 and 1.0 min) and the residual stresses after 60 and 120 s relaxation, at I min height, served as measures of the foams consistency and degree of solidity, respectively. The drainage rate and changes in the air bubbles size distribution with time served as indicators of the foams' physical stability. The two gums had a dramatic effect on both the foams consistency and degree of solidity and to a lesser extent on their stability. In most cases though, the effects were clearly noticeable in foams beaten for 3 min or longer. Since the two gums' effects on the foams properties could not be attributed to stoichiometric considerations, it is suggested that they were primarily due to strengthening the cells walls, an observation that is supported by the relatively small differences in the foams general structure.