4.3 Å . The presence of two
subforms of the β′ polymorph could explain the presence of two fractions
with only a slight difference in melting point, observed in the
DSC results before. The two subforms of the β′ polymorph of palm
oil, β′1 and β′2, have a similar acyl chain packing but different thermodynamic
stability and melting point. The subscript used increases
with decreasing thermodynamic stability, so β′1 is the most stable
β′ form while β′2 is less stable. The subform normally found in palm
oil is the β′1 form ).
Based on the results from both DSC and XRD, a potential mechanism
for the crystallization of the 8% MP blend at 15 °C could be proposed.
A schematic representation of this mechanism is shown in
Fig. 11.