Physical Chemistry of Foods

10.6 CONTACT ANGLES AND WETTING If three different phases are in pairwise contact, thus giving three different phase boundaries, ...

implies that the interfacial tension gASequals the sum of gLS and the projection ofgALon the solid surface. This leads to theYou ...

course impossible. In that case,y¼0 and the solid is said to be fully wetted by the liquid: given enough space, the liquid will ...

an oil layer. Also the solutions of Eqs. (10.10) and (10.11) represent minimum values of the interfacial free energy of the syst ...

the same extent to the triglyceride oil–water interface as to the crystal–water interface, giving the same decrease in interfaci ...

is depicted by the broken line in Figure 10.25b; it applies to solid tristearate, water, and a triacylglycerol oil with various ...

several sweets. The contact angle will then vary with place. Even if the solid is made up of one chemical substance, the surface ...

surfactants, the advancing and receding contact angles are often affected to a different extent; in other words, the hysteresis ...

slower until the maximum height given by Eq. (10.13) is reached. In a horizontal direction, there would be no limit to the liqui ...

thereby reconstituting milk. Most dried soups contain particles that become dispersed and other particles that also dissolve. Fi ...

causescapillary contraction. As illustrated in Figure 10.27c, the surface tension of the water tends to pull the particles towar ...

FIGURE10.28 Interfacial tension gradients in relation to flow of the bordering liquids.v¼linear velocity,g¼interfacial tension. ...

downstream. This implies that ag-gradientis formed. Such a gradient means that there is atangential stress in the interfaceof ma ...

(generally water) between air bubbles will be present. As illustrated in Figure 10.29a, the water will flow downward, and if no ...

g-gradient, hence the A–W interfaces can withstand a tangential stress. Hence the interfaces act like solid walls, so that the d ...

effect will transport wine upward (frame 2), hence a thicker rim of ethanol-depleted wine is formed (frame 3). This rim is subje ...

gives for the ‘‘spreading’’ time tspr&z^4 =^3 Z^1 =^3 r^1 =^3 jDgj
^2 =^3 ð 10 : 19 Þ Some sample calculations: for an O–W i ...

FIGURE10.31 Vessel with a solution of surfactant (denoted by short lines), of which the surface is ‘‘immediately’’ enlarged (fra ...

Question Assume that the experiment illustrated in Figure 10.31 is done with a solution of Na- stearate and with one of Na-myris ...

rheology then is concerned withexcessquantities; in other words, the force needed to deform the bulk materials is somehow subtra ...