Physical Chemistry of Foods

FIGURE10.32 Interfacial rheology. Schematic illustration of various types of deformation of a square surface element and the app ...

10.8.1 Surface Shear Application of a two-dimensional shear stress can be done in various ways, for instance as depicted in Figu ...

The prime cause of the surface shear viscosity is friction between surfactant molecules; the cause of surface shear elasticity i ...

determination of other surface properties is generally needed for a reasonable interpretation of the results. 10.8.2 Surface Dil ...

whereD¼diffusion coefficient,t¼time scale of the deformation, andcis bulk surfactant concentration (mol?m
^3 );Gshould be in mol ...

lowest value ofc, because transport of surfactant by diffusion is slower, as it has to occur over a greater distance. The depend ...

wheredis the film thickness. The factor of 2 arises because a film has two surfaces. Some results are given in Figure 10.35. It ...

deformation and whatg-gradient can be formed. The latter determines the magnitude of the tangential stress that an interface can ...

insoluble monolayer at the interface: on dilatation the interface reacts in a fully elastic manner. In most cases, however, the ...

solid provides the stress needed to arrest the surface. Something similar must happen for some adsorbates at afluid interface. P ...

varying among surfactants. Additional surfactant added above the CMC forms micelles; this means that the surfactant activity doe ...

thereby the cleaning action of detergents, the occurrence of capillary displacement, the wetting by and the dispersion of powder ...

for polymeric surfactants, especially proteins. Interpretation of the results is not easy. A high surface shear modulus probably ...

Also interesting is E. Dickinson, D. J. McClements. Surfactant micelles in foods. In: Advances in Food Colloids, Blackie, Glasgo ...

11 Formation of Emulsions and Foams There are two main methods of making dispersions. One issupersaturation of the continuous ph ...

Many aerated foods are dispersions of air (e.g., whipped egg white) or carbon dioxide (e.g., a head on beer) in water. Emulsions ...

can lead to the formation of bubbles or drops—and from the continuous phase to these particles—whereby they can be disrupted int ...

An important point to be made is that processes occurring during formation and changes in the system at rest (‘‘instability’’) s ...

Question 1 A company wants to make O–W emulsions by means of membrane emulsification. They decide to use a ‘‘membrane’’ with por ...

11.2 FOAM FORMATION AND PROPERTIES When a foam is made in a vessel containing a low-viscosity liquid, either by injection of air ...