Emulsification properties of proteins extracted from beef lungs in the presence of xanthan gum using a continuous rotor/stator system

The emulsifying properties of beef lung protein concentrate (BLPC) in the presence of xanthan gum were investigated under steady state conditions using a continuous rotor/stator device. Experiments were defined using design of experiments methodology which included formulation and process variables. The influences of xanthan and protein contents were studied first on the properties of the continuous phase, namely viscosity and interfacial tension. Then, emulsion properties, such as average droplet diameter, viscosity and stability against creaming were analyzed using a split-plot design. Experimental results showed that rotation speed played the key role on droplet size reduction, whereas emulsion texture depended slightly on process variables and was governed by the recipe, i.e. by protein and xanthan contents. Conversely, emulsion stability resulted simultaneously from formulation and process factors. Finally, a comparison of BLPC with commercial sodium caseinates in similar recipes under identical operating conditions highlighted the high emulsifying properties of these beef lung proteins.