Effect of composition and process parameters on elasticity and solidity of foamed food

The objective was to investigate the impact of formulation and process parameters on the ability of food emulsions to form stabilized whipped emulsions under steady-state flow conditions using small-deformation rheological analysis. Three kinds of food emulsions were studied; formulation and operating conditions were modified in order to increase foam solidity which was strongly correlated to the stability of food microstructure. Results showed that for a white sauce, foam solidity depended slightly on operating conditions and was similar to the emulsion. Conversely, solidity was higher after foaming and sensitive to operating conditions for unfrozen foams from an ice cream mix, whereas it could decrease drastically after foaming for a fresh cheese. These results were explained using the description of the microstructure of these emulsions. The white sauce presented a polymeric gel behaviour due to stabilizers which was not deeply modified by foaming. Conversely, the ice cream mix corresponded to a viscoelastic fluid that became more solid due to high gas fraction and partial coalescence of fat globules during foaming. Finally, the particle gel structure of foamed cheese was shown to be irreversibly broken by shear, inducing a less solid behaviour after foaming. Solidity was achieved only by improving the recovery rate of the gel structure.