Physical Chemistry of Foods

many of the properties of natural micelles are significantly changed, but the particles roughly keep their size and shape. Near ...

with the occurrence ofsyneresis, i.e., the expulsion of liquid from the gel, which is undesirable in most gels. On the other han ...

involved. If the junction strength is not too high, it may lead to breaking of a strand; so loose ends are formed, which can for ...

Rheological Properties. We have seen that the permeability of a particle gel is related to the fractal structure in a simple way ...

strands to stretch. We now havea¼2, and the parameterK^0 includes the Young modulus of the primary particles. Its value tends to ...

It is also seen that theproperties of the primary particlesplay a large role. This is borne out by results of dynamic measuremen ...

It may be added that not all variables have been discussed, such as pH, ionic strength, and solvent quality, or the time scale o ...

applied pressure will, of course, speed up the process. Sincepsynis quite small—of the order of 1 Pa—external pressures can have ...

Many proteins form a coarse precipitate rather than a gel if the pH is very close to the isoelectric point, combined with a high ...

An example is given in Figure 17.19. It is seen that a gel was formed after about 30%of the protein had been denatured, i.e., at ...

Presumably, about the same happens during the formation of most heat-set protein gels, although often at a faster rate. (In the ...

As illustrated in Figure 17.14d the value of the modulus increases with decreasingtemperature, once a gel has formed. This is as ...

Polymer–Polymer. The following alternative situations may occur. The two polymers form a homogeneous solution. If now the condi ...

Polymers with Heat-Setting Proteins. Consider a solution of a globular protein at a pH above its isoelectric point that will giv ...

emulsifying oil in a surface active polymer solution, say gelatin, after which the system is allowed to set, e.g., by cooling. B ...

gas bubble, its shear modulus is simply given by the Laplace pressure Gp¼pL¼ 4 g d ð 17 : 19 Þ For a protein-covered oil droplet ...

using a homogenizer at 25 MPa. Earlier experiments gave at this homogenizing pressure droplets ofd 32 & 0 : 6 mm, which woul ...

This concerns especially butter, margarine, shortening, and cocoa butter. The key rheological parameter is mostly the yield stre ...

FIGURE17.21 Values of various crystallization parameters as functions of timet after cooling of a mixture of 12%hydrogenated pal ...

lnb 0 value, the initial crystal size is larger, but not any more at a longer time scale. However, some reservations have to be ...