Physical Chemistry of Foods

between two parallel glass plates, cells of equal volume can show a regular array of close-packed hexagons, as in a honeycomb. T ...

gravitational pressure. The relation is pL¼ g R ¼rwgH ð 11 : 1 Þ whererwis the density of the aqueous phase (assuming that of ai ...

11.2.2 Drainage It will, of course, take time to obtain a dry foam, since the water has to drain from it, and drainage is greatl ...

protein surfactants can cause the surfaces to be fully stagnant. It is indeed observed that such surfactants cause significantly ...

least about 1 mg of surfactant per ml, or 0.1%. If an overrun of 1000%is desired, with a bubble size of 30mm, a similar calculat ...

concentration was equal and all of the proteins are well soluble. The most likely explanation is the rate of (partial) unfolding ...

caused by denaturation, tends to decrease overrun, simply becauseG?then is much higher, implying that more protein is needed to ...

fluctuations then become large enough to cause sufficient stretching of films between bubbles to induce coalescence. Generally, ...

whereby most of the water is converted into ice; this makes a ‘‘solid foam.’’ Particlesthat adhere to the A–W interface (see Sec ...

on a particle is expressed by a dimensionless Weber number, We: sext ð 1 = 2 ÞpL ¼ sextd 2 g ð 11 : 5 Þ We has to be of order un ...

In this section,g is assumed constant. This means either that no surfactant is present (then single drops are considered) or tha ...

characteristic length equals drop diameterd, and the velocity is that of the drop relative to the adjacent liquid. The transitio ...

O–W emulsions, regime TI ifZCis not much higher than that of water; for a higher viscosity it tends to be regime TV, especially ...

haveD¼We. For larger values of We, the drop is further deformed as depicted, and it breaks if We>Wecr. Values of Wecrare give ...

given size. IfZD> 4 ZC, the drop is not disrupted at all. The magnitude ofD remains small and the slightly elongated drop sta ...

Question How large a velocity gradient would be needed to make an O–W emulsion with droplets of 1mm diameter in plane hyperbolic ...

The eddies have lifetimes given by tðleÞ& le u^0 ðleÞ ¼l^2 e=^3 e
^1 =^3 r^1 =^3 ð 11 : 9 Þ Hence the smaller the eddies, th ...

Regime TV. As mentioned, the relation for regime TI can only hold if Redr>1. Redrcan be obtained by combining Eqs. (11.8) and ...

ratio. The relation for droplet size then becomes dmax&ge
^1 =^2 Z
c^1 =^2 ð 11 : 14 Þ This is again a very simple relation. ...

every small volume unit of emulsion has to pass close to the stirrer tip to allow formation of the smallest droplets obtainable. ...