Influence of the second emulsification step during production of W/O/W multiple emulsions: Comparison of different methods to determine encapsulation efficiency in W/O/W emulsions

As water encapsulation is crucial for most W/O/W emulsion applications, we compare different measurement techniques for its analysis. Therefore, we produce two different W/O/W emulsions that should have different EE, as we change the applied shear rate during the second emulsification step. We use the marker based techniques photometry (with Vitamin B12) and electroconductivity (using NaCl), rheometry as another indirect technique as well as DSC as a direct measurement method. It was found that photometry was not capable to detect differences between the emulsions. As DSC is the only direct technique, we conclude that it is most suitable to measure EE.