Physical Chemistry of Foods

Thenumber of carbon atoms. The higher it is, the higher areTm andDHf. The larger the molecule is, the greater the gain in confo ...

solute, andTmits melting temperature. Figure 15.18 gives a calculated example for a mixture of equal parts of tristearin (SSS) a ...

ternary mixtures, fairly simple equations are available, but the relations are intricate for more components. Natural Fats. Figu ...

with temperature, which points to a very wide compositional range. This is indeed the case, also because simple hydrogenation no ...

15.4.2 Polymorphism Imagine the following experiment: a fat is melted, e.g., at 40 8 C, and a little of the molten material is s ...

Triglyceride molecules have three chains and a glycerol, residue, and— for the same subcell—packing of the moleculescan occur in ...

If one of the chains is an oleic acid residue, a bended (L3) conformation is often assumed for these chains, as illustrated for ...

below theaclear point); this is because the constraints imposed on the molecules upon incorporation in the crystal lattice are l ...

A typical example of the changes occurring upon cooling and heating is given in Figure 15.21 for PPP. Upon cooling (curve 1), on ...

(generally by differential scanning calorimetry). Results are shown in Figure 15.22 (curves marked lnb¼0) for theaandb^0 polymor ...

Six polymorphic forms are generally observed, and some properties are given in Table 15.4. The common notation is from I to VI, ...

Question A company producing olive oil has occasionally a lot that is unfit for normal use owing to off-flavors. Purification pr ...

Note What the investigators should do first is to determine by DSC the needed parameters and check by x-ray diffraction which of ...

crystals can form during crystallization in a less stable polymorph, but they will soon transform into the most stable polymorph ...

may even within a minute be transformed intob^0. Theb^0 -form generally has a longerlifetime. In multicomponent fats,acrystals t ...

a 5. Hence the surface of the crystals will be in local equilibrium with the liquid phase. There is no equilibrium at the interf ...

transitions, since these invariably cause the melting temperature to increase. In the figure we see that the new peak is at a lo ...

whereas crystallizing in steps atT 2 andT 3 would give a 3
a 2 a 5
a 2 þ a 5
a 3 a 5
a 2 6 a 2
a 1 a 4
a 1 ¼ 0 : 23 þ 0 : ...

impurities. Monoglycerides may readily form inversed micelles in the presence of a trace of water, and the micelles are possibly ...

other triglyceride crystals, and presumably also for crystals in another polymorph. The hysteresis at lower temperatures has qui ...