Physical Chemistry of Foods

the sorption isotherm is thus of importance for deciding under what humidity of the air a food material should be stored. In man ...

led to equilibrium. In a spray-dried product, the particles are for the most part about 0.05 mm in diameter or larger. Given the ...

8.3 ‘‘WATER BINDING’’ The quotation marks in the heading of this section signify that water binding is a questionable term. In t ...

instance with respect to the ‘‘surface’’ of a macromolecule. If there is no net attraction or repulsion between the surface and ...

Immobilized water. This is meant to be water that does not leak out of a solidlike food. It is present in closed cells, in open ...

1 : 8? 10 ^5 =RT& 7? 10 ^9 per Pa at room temperature. If we apply an external pressure of 1 bar (10^5 Pa), it would be eq ...

desorption and adsorption curves, as has been shown for rigid porous materials, say minerals. However, such hysteresis is genera ...

Answer The sucrose solution has anawof 0.94 according to Figure 8.1. A mole fraction of 0.05 implies per 100 moles 5 6342 ¼1710 ...

make quantitative predictions. At very smallw, the system may be in a glassy state; this is further discussed in Section 16.1. B ...

greatly upsets the interpretation of results on diffusivity, since it is not well known what factors cause crack formation; it g ...

then be more important. Nevertheless, reactions involving water, like the various kinds of enzyme-catalyzed hydrolysis, will all ...

function ofwonly, the relation betweenawandwmay vary considerably. This then means that the relation between diffusivity andawva ...

It is generally observed, for heat inactivation of enzymes or killing of bacteria, that at a smallerwboth the (apparent) activat ...

case, water activity would be the determinant variable. Another example may be the curve for chymosin in Figure 8.11. Here,kis a ...

activity. Microorganisms vary widely in the water activity that they can tolerate. Generally, the lowestawfor growth is for Bact ...

Presumably, ethanol then is more damaging for the cytoplasm than glycerol. (It may be noted thataw¼0.973 caused by ethanol corre ...

where an attempt is made to keep foods fresh without intense heat treatment and without adding large concentrations of bacterici ...

solute onto particles or macromolecules and greatly depends on the nature, especially on its molecular size, of the solute. Boun ...

D. Simatos, J. L. Multon, eds. Properties of Water in Foods. Nijhoff. 1985. H. Levine, L. Slade, eds. Water Relationships in Foo ...

9 Dispersed Systems Most foods are dispersed systems; in other words, they are physically heterogeneous. This means that their p ...