MGC and SAT of OGs
Table 1 shows the results of fatty acid composition of vegetable oils
and monoglycerides obtained by GC. The difference in the composition of
saturated (SFA), monounsaturated (MFA) and polyunsaturated (PFA) fatty
acids was observed in both oils and MY. CA was found to be rich mostly
in medium-chain MFA and PFA (66.28 and 27.78%), while CN is mainly
composed of short-chain SFA (90.82%). FA composition for these oils is
similar to that reported by other authors (Garcia-Andrade et al., 2020),
however, the FA profile of MY was different from that reported by
Giacomozzi et al. (2021), (C16:0 43.91±0.07% and C18:0 53.65±0.07%).
Even being the gelling agent Myverol, the product used for this
investigation had a higher percentage of C16:0 (palmitate, 58.72±0.10%)
and lower percentage of C18:0 (stearate 39.67±0.11%). However, it is
possible that the degree of saturation of the oils affected the
properties of the oleogel.
The MGC of MY at room temperature was different for each type of oil (CA
= 2.5% w/w, CN = 2% w/w) (Fig. 1), this due to differences in their
chemical composition (Table 1), where a composition mostly saturated in
CN allows MY to retain the liquid phase more easily. However, for
comparative purposes, we continued with 2.5% w/w MY in both oils in the
following evaluations. It is possible that using a lower storage
temperature may require a lower amount of gelator due to reduced
intermolecular Brownian motion, however, a lower temperature also
promotes sub-α crystallization, and consequently there is a greater
likelihood of early polymorphism (Lopez-Martinez et al., 2014). The MGC
values found in this work for CA and CN are lower than those reported by
other authors for oils with high triolein content using a commercial
monoglyceride (~3.5% w/w) (Aguilar-Zárate et al.,
2019). It is known that this concentration depends on the solubility of
the gelling agent in the vegetable oil, as well as the cooling rate and
temperature. However, the solubility is closely linked to the solvent
composition. In addition, a higher concentration of gelant results in
lower solubility, which allows greater molecule-molecule interaction of
the gelant, promoting self-assembly and having higher oil retention
capacity.