Surfactant Association Structures, Microemulsions and Emulsions in Food

Surfactant Association Structures, Microemulsions and Emulsions in Food 

From the above discussion, a surfactant/co-surfactant combination for a microemulsion is clearly of little use to stabilize an emulsion. This is a disadvantage when a multiple emulsion of the 5 O/W type is to be formulated, whereby the W/ O system is a microemulsion. This problem has been resolved by Larsson et al. [13], who used a surfactant combination to stabilize the microemulsion and a polymer to stabilize the emulsion. 

The formulation of food systems as microemulsions is not easy, since addition of triglycerides to inverse micellar systems results in a phase change to a lamellar liquid crystalline phase. The latter has to be destabilized by other means than adding co-surfactants, which are normally toxic. An alternative approach to destabilize the lamellar phase is to use a hydrotrope, a number of which are allowed in food products. 

8 Surfactant association structures, microemulsions and emulsions in food 

A typical phase diagram of a ternary system of water, ionic surfactant and long chain alcohol (cosurfactant) is shown in Fig. 5.14. The aqueous micellar solution A solubilizes some alcohol (spherical normal micelles), whereas the alcohol solution dissolves huge amounts of water forming inverse micelles, B. These two phases are not in equilibrium with each other, but are separated by a third region, namely the lamellar liquid crystalline phase. These lamellar structures and their equilibrium with the aqueous 

As discussed above, for emulsion stabihzation in food systems lamellar liquid crystalline structures are ideal. At the interface, the liquid crystals serve as a viscous 

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These systems are widely used in many food products. A section will be devoted to the interfedal phenomena in food colloids, in particular their dynamic properties and the competitive adsorption of the various components at the interlace. The interaction between proteins eind polysaccharides in food colloids will be briefly described. This is followed by a section on the interaction between polysaccharides and surfactants. A short review will be given on surfactant association structures, microemulsions and emulsions in food [3]. Finally, the effect of food surfactants on the interfacial and bulk rheology of food emulsions will be briefly described. The formation of aggregation networks and the application of fractal concepts is then considered. This is followed by a section on applications of rheology in studying food texture and mouth feel. 

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