3.4.2. Blends of fats and oils
In order to match the more adequate melting profile for product
formulation, such as for margarine, modified butter, and cocoa
replacers, fats with a high melting point can be blended with oils
(Oliveira, Rodrigues, Bezerra, & Silva, 2017). Taking into account that
MUFA, PUFA, and SFA are present in different ratios in Amazon crude fats
and oils, particular FA profiles can be obtained with their blends.
Table S2 (Supplementary Material) shows the calculated FA compositions,
atherogenicity, and thrombogenicity indexes for the blends prepared
during the course of this study. As expected, addition of oils to the
solid fats reduced AI and TI. Tucuma kernel oil, for instance, had its
AI reduced from 14.31 to 7.97 with the addition of 10% patawa oil and
to 1.89 at 50:50 ratio. Similar results were obtained for murumuru fat
and pracaxi oil blends, in which AI/TI were reduced from 14.60/6.69 to
2.40/1.21 at 50:50 ratio blend. These results are quite important since
the use of these blends in replacement of partially hydrogenated oils in
formulations of spreads, shortenings or margarines, for example, might
present not only technological advantages but also improved nutrition
values.
Figures S1 to S3 (Supplementary Material) show melting curves of the
blends. All blends showed multiple endothermic peaks related to the
variety of TAGs in their compositions. The melting curve of tucuma
kernel oil/patawa oil blend presented two main endothermic peaks in all
ratios. The first probably corresponded to the melting of OOO and OOP
fractions from patawa oil, and the second was probably related to the
melting points of LLL, LLM, and MML fractions, the main saturated TAGs
of tucuma kernel oil. As expected, the enthalpy of the first peak
decreased as the content of patawa oil decreased. The murumuru
fat/pracaxi oil blends at the ratios of 50:50 and 60:40 exhibited two
main peaks. The first was related to the melting of OOBe fractions,
found in pracaxi oil, and the second (around 30 °C) probably
corresponded to the melting of TAG fractions rich in lauric and myristic
acids from murumuru fat. Notably, at ratios from 70:30 to 90:10 only one
main peak was found. This is probably due to the fact that the
decreasing in pracaxi oil content decreased the melting enthalpy of
fractions rich in unsaturated TAGs, promoting an overlapping of the two
main peaks. This could be interesting if one desires a blend without
phase separation considering storage conditions.
The melting behavior of Bacuri fat/Brazil nut oil blend was very close
to the Bacuri fat melting profile. Indeed, one of the TAG fractions of
bacuri fat is rich in oleic acid and presented melting temperatures very
close those of Brazil nut oil fractions. However, when compared to
Bacuri fat, the last melting peak of the blend was slightly decreased,
especially at 50:50 ratio. This means that the fraction which melted
around 53 °C in the pure bacuri fat sample, when blended with Brazil nut
oil tended to melt around 46 °C. These results showed that one might
decrease the melting temperature of bacuri fat and alter its melting
profile by blending it to low melting TAGs, such as those observed in
Brazil nut oil, broadening its range of industrial application.