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

• A multi-scale approach is used to study oil-in-water and water-in-oil emulsions.
• Pumping capacity and tip velocity are key variables for emulsion manufacture.
• There is a relationship between droplet size and near infrared spectra.
• There is a relationship between creep compliance modulus and viscoelasticity.

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 and 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) (Zölzer and Eicke, 1993, Ewoldt and McKinley, 2007 and 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, Sjöblom et al., 2003 and 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.