Local Impedance Spectroscopy: A Potential Tool to Characterize the Evolution of Emulsions and Foams

The potential of local impedance spectroscopy (IS) to access changes in emulsions and foams has been investigated. As test systems we used the separation of a simple oil/vinegar mixture as well as the whipping process of dairy cream. For the latter, IS data were compared to particle size distribution (PSD) measurements. Our measurements show that local IS is indeed a valuable tool to locally study processes in emulsion. On one hand, it seems to be very sensitive to small water quantities in oil thus being a suitable method for process control in water removing processes. On the other hand, concerning fat foams, it seems to be able to detect the evolution of foam structures. Both examples show that local IS could be a helpful tool for process control.