Physical Chemistry of Foods

often stick out partly in the one, partly in the other phase. This is not possible at solid interfaces. At a fluid interface (ga ...

FIGURE10.5 Schematic examples of the concentrationcof a solute in water as a function of the distancezin a direction perpendicul ...

of the dividing plane, the same curve holds in this case for the concentration of the water, but at a different vertical scale.) ...

the lowestgattainable. Consequently, it is better to relate surface activity to the concentration at whichPhas half its maximum ...

magnitudes decrease by a factor 28 when going from 12 to 18 C atoms. (As a parameter to characterize the surface activity, the s ...

illustrated in the Question just discussed. Information about Gis also needed when the stability of a dispersion has to be studi ...

net interaction energy between surfactant molecules when in the adsorption layer, which can vary greatly among surfactants. The ...

removal will be larger for a larger molecule. This is the main reason why polymeric substances can be so very surface active (se ...

If thesurface fractioncoveredyis appreciable, large deviations from Eq. (10.4) occur. The discrepancy is especially large for l ...

O–W than at the A–W interface, the reason thatPtends to be higher at the O–W interface. See Figure 10.14 for proteins. At highP ...

Only a limited number are used in foods. These include polar lipids, especially monoacylglycerides and phospholipids. Macromolec ...

A small part of a phase diagram is given in Figure 10.10a. An important characteristic is the temperature at which the apparent ...

FIGURE10.9 Highly schematic examples of some association colloids. (a) Micelles and bilayers. (From E. Dickinson, D. J. McClemen ...

for quite long times, and the monoglycerides do adsorb at interfaces. Once adsorbed, they remain so, even at low temperature. Th ...

The difference decreases as the concentration of the surfactant, hence the value ofG, increases. The plateau values ofGdiffer gr ...

when adding NaCl. From the discussion in Section 2.3, it follows that the activity is given byg+(cþ 6 c
)0.5, whereg+is the ion ...

‘‘adsorb,’’ albeit at some distance from the interface. However, the theory is intricate and there is no complete consensus. Sin ...

10.3.2 Polymers In this section, we will consider only water-soluble polymers adsorbing at homogeneous surfaces, A–W, O–W, or S– ...

FIGURE10.12 Mode of adsorption of various polymers from an aqueous solution. Very approximate. See text. In (c) some nonadsorbed ...

and for the amphiphile of the order of 1kBT. Consequently, the affinity of the protein for the surface is far greater than that ...