Food Lipids: Chemistry, Nutrition, and Biotechnology

Figure 6 Schematic representation of the crystal structure of the triclinic form of tricaprin
projected on the bc plane. (Reproduced with permission from Ref. 8.)
stearin. Synthesized, stereospecific 1,2-dioleoyl-3-acyl-sn-glycerides with even carbon-saturated
fatty acyl chains of 14–24 carbons have a trilayer packing structure
[23].
III. POLYMORPHISM AND PHASE BEHAVIOR OF NATURAL FATS
As described earlier, solids with the same composition that exhibit different structural
geometry are said to be polymorphic. The geometry of a particular polymorph confers
unique physical properties beyond that of X-ray diffraction, although the X-ray
diffraction pattern provides for unequivocal polymorph assignment [24]. Intramolecular
and intermolecular conformation can also be inferred from infrared, Raman, and
other forms of vibrational spectroscopy. Dilatometry and melting behavior are also
used to evaluate the polymorphic nature of fats. Most multicomponent fats exhibit
monotropic not enantiotropic polymorphism, and transformations proceed only from
less stable to more stable forms [13].
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