External factors, as thermal variation, shear, and additives,
applicable in crystallization processes also influence the functionality
of vegetable oils and the organization of the TAGs. A
small disturbance in these properties will change the kinetics of
polymorphic transformations and hence can affect the crystallization and melting behavior of oils and fats. As an alternative
to improve and/or modify these attributes, it is possible to
use crystallization promoters, such as hard fats, additives obtained
by total catalytic hydrogenation of liquid oils. Hard fats
present homogeneous saturated TAG composition, high melting
point (>40 C) and can act as modifiers of the crystallization
process. Furthermore, they can act as preferential nuclei in the
crystal lattice ordering and induce specific polymorphic habits.
Sato et al. (2013) reported that the relative rates and the extent of
crystallization of a, b0 and b polymorphs are influenced by the rate
of nucleation, which increases with the increase of supercooling
and is governed by the activation free energy for nucleation,
temperature, mass and heat transfer rates, and attachment/
detachment rates of lipid molecules between cluster and liquid.