Physical Chemistry of Foods

Question Consider again Question 2 at the end of Section 11.1. Can you make a rough estimate of the proportion of the liquid us ...

Different surfactants give different results, as illustrated in Figure 11.11. Plateau values are obtained at high surfactant con ...

very fast (say, in 1ms), and it involves a temporary increase of the surface area of the drop, maybe by a factor of 2, which wou ...

The rate of recoalescence presumably depends on the time lapse between mutual drop encounters tenc relative to the time needed f ...

FIGURE 11.12 Schematic illustration of the mechanisms relevant for the prevention of recoalescence of newly formed oil drops dur ...

coalescence in a finished emulsion and during emulsification are due to different mechanisms, at least for many surfactants. Fig ...

modulus at a quite smallGvalue (expressed in mg?m
^2 ), whereas for b-caseinESDwould be very small forG<1mg?m
^2. Hence preve ...

states that the phase in which the surfactant is best soluble becomes the continuous one. The explanation presumably is thatg-gr ...

conditions are equal, except for the phase in which the (small-molecule) surfactant is present. It is seen that the retardation ...

variable oil–water ratio, this way of plotting leads to consistent results (plotting as in Figure 11.15a does not). Results for ...

at a high pressure and the resultingd 32 ¼0.7mm. (a) Why is it beneficial to add NaCl to the aqueous phase? (b) What type of emu ...

11.5 RECAPITULATION Foam bubbles can be made via supersaturation of a gas (generally CO 2 )or by beating in air. Emulsions are g ...

Roles of the Surfactant. Emulsions and foams cannot be made without surfactant being present. The prime function of the surfacta ...

A compilation of papers on foam properties and making is A. J. Wilson, ed. Foams: Physics, Chemistry and Structure. Springer Ver ...

12 Colloidal Interactions In Chapter 3, bonds and interaction forces between species of molecular size were briefly discussed. I ...

between the surfaces over which interaction forces are significant is nearly always much smaller than the particle size. The int ...

than its thicknessh, the interaction free energyVthen should be given per unit surface area of the film, i.e., in J?m
^2. In the ...

newtons, for films in pascals (N?m
^2 ). The net pressure in a film due to interaction forces is called thedisjoining pressure. ...

than about 5 timesh, the result is VvdW;p¼
A 12 ph^2 ð 12 : 2 Þ where VvdW,p is expressed in J?m
^2. Also for some other geomet ...

constant of themediumbetween the two bodies concerned is also involved in the interaction energy. If, moreover, the materials 1 ...