Influence of internal water phase gelation on the shear- and osmotic sensitivity of W/O/W-type double emulsions

Double Emulsions Relevant to Food Systems: Preparation, Stability, and Applications

“…The consensus of accumulated evidence would therefore seem to indicate that gelation of the W1 phase of a W1/O/W2 emulsion leads to a significant improvement in initial yield of the W1 phase (Sapei and others ; Carrillo‐Navas and others ), in the DE storage stability (Scherze and others ; Surh and others ), in the thermal stability (Oppermann and others ), and also in the shear stability (Mun and others ; Balcaen and others ). Furthermore, a DE system with a gelling agent in the W1 phase appears to be rather less sensitive to the concentration of electrolytes in the W2 phase (Perez‐Moral and others ) or to other sources of imbalance in osmotic pressure (Balcaen and others ). Another beneficial consequence of W1 phase gelation is that it allows the investigator to reduce the amount of PGPR that is required to form the primary W1/O emulsion (Mun and others ; Perez‐Moral and others ).…”

“…During the physical characterization of a DE system, the investigator needs to be aware of the possibility of measurement errors arising from induced osmotic gradients. In particular, the necessity for dilution under close to iso‐osmotic conditions has been well documented in relation to the reliability of microscopy observations (Balcaen and others ) and particle size analysis (Bonnet and others ; Andrade and Corredig ). The phenomenon of osmotic imbalance is also pertinent to the influence on emulsion stability of the aqueous phase conditions present in in vitro DE digestion studies involving simulated duodenal and gastric fluids.…”

“…Under hypo‐osmotic conditions (low pressure in W2 phase, high pressure in W1 phase), the swelling of individual droplets may be observed in the depression of a light microscope slide (Yan and Pal ), enabling DE formulation conditions to be optimized with respect to osmotic gradient sensitivity. Conversely, in order to avoid any droplet swelling due to osmotic differences during measurement, the DE system should be dispersed in an electrolyte solution such as 0.1 M KCl (Balcaen and others ). Since droplet stability on a microscope slide can be affected by the pressure of the coverslip, a microscope slide with a shallow depression has long been recommended (Matsumoto ); nowadays a “diagnostic slide” is commercially available for this purpose.…”

W/O/W Multiple Emulsions as the Functional Component of Dairy Products

“…Especially high-field NMR methods permit descriptions of emulsions at the molecular level [168]. By NMR T 2 -relaxometry with the Carr-Purcell-Meiboom-Gill (CPMG) sequence it is possible to prove whether internal water phases of w/o and w/o/w emulsions are gelled [160]. NMR also supports measurements of droplet size.…”

Fat crystals: A tool to inhibit molecular transport in W/O/W double emulsions

“…[4,8] Four assisted transport mechanisms have been defined in case of water transport, that is, transport through spontaneous emulsification, reversed micelles, thinned lamellae, and hydrated surfactants. [1,4,8,12,[15][16][17][18][19] Most of the studies regarding quantification of the (water) transport kinetics illustrate the importance of the W/O/W formulation and focus mainly on osmotic regulation, emulsifier characteristics and concentrations, or on the physical state of matter of the internal water droplets (e.g., gelation of the internal water [20,21] ). Apart from the viscosity of the oil phase, [4,11,22] the impact of the nature of the oil phase is largely unexplored considering exchange kinetics.…”