Fig. 1b shows the hardness of the industrial fats and their mixtures
with sucrose behenate at 20 and 25 C. At 20 C, the addition
of sucrose behenate increased the hardness of palm oil (from
1.30 ± 0.07 to 4.13 ± 0.18 N) and of the palm mid fractions (from
13.77 ± 1.08 to 25.34 ± 0.90 N), while for the interesterified fats, a
small reduction was observed (from 3.12 ± 0.19 to 2.25 ± 1.03 N).
At 25 C, palm oil showed the smaller hardness (0.31 ± 0.03 N),
although it has a solid content similar to interesterified fat and
to PMF. Palm oil containing sucrose behenate showed a hardness
of 1.39 ± 0.21 N at 25 C, indicating an almost fivefold increase in
the hardness of the palm oil. On the other hand, a slighter difference
in hardness was observed when sucrose behenate was added
to the interesterified fat (from 1.0 ± 0.02 to 1.15 ± 0.11 N), indicating
that, despite contributing to the change in the solid fat content,
sucrose behenate did not change the hardness of the interesterified
fat, which maintained its softness. Interestingly, the addition of
sucrose behenate caused a large increase in the hardness of the
palm mid fraction at 25 C, although no effect on their solid fat content
was observed. These results can be explained from the different
crystal network morphologies formed by the addition of
sucrose behenate, as shall be seen later.