The application of a multi-scale approach to the manufacture of concentrated and highly concentrated emulsions

In this work, a multi-scale approach is applied to the emulsification process of concentrated emulsions. Whereas a vast number of studies have focused on either formulation or processing ( Mason et al., 1997 , Pal, 1999 , Dimitrova and Leal-Calderon, 2004 , Derkach, 2009 , Capdevila et al., 2010 ), we propose a transversal study that includes those variables and also covers aspects of the rheological behavior, the droplet size and the near infra-red spectra (NIRS). The analysis on oil-in-water (O/W) and water-in-oil (W/O) emulsions yielded results that depend on the energy incorporated during the emulsification process. First, depending on the tip velocity and pumping capacity of the impeller, a certain amount of energy can be incorporated to a given formulation (i.e., concentration of the dispersed phase). Second, as a consequence, the properties (rheology and droplet size) ( Zolzer and Eicke, 1993 , Ewoldt and McKinley, 2007 , Evans et al., 2009 ) of the resulting emulsion are set and mathematical relationships are established. Finally, it is possible to visualize via NIRS not only the changes in concentration ( Aske et al., 2002 , Sjoblom et al., 2003 , Araujo et al., 2008 ) but also the influence of the changes in droplet size and couple all three aspects. The novelty of these results rests on the treatment of the energy as a transversal variable to the scales studied instead of handling only the formulation variables.