Physical Chemistry of Foods

It is often observed that the number of catalytic impurities depends on temperature according to logNcat&A
BT ð 14 : 13 Þ wi ...

be mentioned that macroscopic surfaces (vessel walls, etc.) can catalyze nucleation by the same mechanism as shown in Figure 14. ...

It should be mentioned that frames 3–5 in Figure 14.5b are two- dimensional and the real (three-dimensional) situations will gen ...

14.2.3 Other Aspects The importance of the magnitude of the rate of nucleation is (a) that it determines the supersaturation nee ...

Secondary Nucleation. It is often observed that agitation during crystallization enhances the number of crystals formed, which p ...

diameter 4mm has about that volume. Upon cooling an emulsion of the same milk fat, one would thus predict that droplets of about ...

this case C and E. Between these pointsG^00 <0 and, as illustrated for composition D, any demixing, however small, will lead ...

It should be noted that Figure 14.8 gives just one example and that the relations can be very different. The dependence of solub ...

14.3 NUCLEATION IN A FINELY DISPERSED MATERIAL When a bulk material contains about one catalytic impurity per mm^3 at a given su ...

which is the volume fraction of the material that is in droplets containing crystals. This is not necessarily the fraction froze ...

vNcat>5,ymax&1. The results shown in Figure 14.6a have been obtained in this way; by using emulsions of variousvvalues, t ...

small temperature range all droplets still devoid of crystals then (partially) crystallize. For triglyceride oils, this especial ...

Answer What is first needed is the magnitude ofv¼pd 633 =6. Assuming the emulsion to have been made in a high-pressure homogeniz ...

14.4 FORMATION OF A GAS PHASE Liquid–gas transitions are common during food processing or storage, but they often occur at the b ...

Nucleation in a crevice (as in frames 4 and 5) cannot be ruled out; see, however, the discussion below under ‘‘Seeding.’’ A prac ...

places on the wall. This is because the contact angle at a glass surface is so small (in fact it is zero) that the Laplace press ...

production. This concerns especially puff pastry, and also several types of biscuits (cookies). The gas cells are for the most p ...

less dependent on the degree of supersaturation than is homogeneous nucleation. In some systems, copious secondary nucleation ca ...

instance, considerable hysteresis is observed between cooling and heating curves of the fraction of the fat being solid. Emulsio ...

R. H. Doremus. Rates of Phase Transformations. Academic Press, Orlando, FL, 1985. especially Chapters 5 (nucleation from condens ...