appeared and corresponded to a β′1 polymorph. A similar result was
obtained at 25 °C. It can thus be concluded that palm oil exhibited a direct
crystallization from the melt into a β′1 polymorph above a certain
cut-off temperature, while at lower temperatures formation of α crystalswas
followed by a polymorphic transition into β′1 crystals. The crystallization
mechanism of palm oil is schematically shown in Fig. 11.
In this study, the cut-off temperature is situated between 20 and
25 °C. Several authors demonstrated that the isothermal crystallization
behavior of palm oil depends on the crystallization temperature
but have found different cut-off temperatures ranging from 22 to
25 °C . Fredrick et al. still observed a two-step crystallization
at 25 °C. These differences can probably be attributed to a difference
in experimental conditions on the one hand and a difference in
palm oil composition
on the other hand.