Vegetable and Mineral Oil Oleogels Developed at different Monoglyceride
to Lecithin Molar Ratios
Abstract
We studied the thermomechanical and microstructural properties of
oleogels developed with 2.1 to 15.7 Moles of monoglycerides/Mole of
lecithin (MG/LC). The oleogels were developed (15°C) in vegetable (VO)
and mineral (MO) oils using at each MG/LC 2% or 4% total mass of
gelator. During oleogelation a synergistic MG-LC interaction existed
deriving in the development of MG-LC cocrystals even below the gelators’
minimum gelling concentration. The cocrystals delayed the Lα→β
polymorphic transition and worked as an active filler of the oleogels’
crystal network. In the VO, the oil with the highest relative polarity,
the oleogels were structured by a network of β crystals where the
cocrystals acted as an active filler. In the MO, the oil with the lowest
relative polarity, the cocrystals’ development was favored while the
Lα→β transition occurred just in the 15.7 MG/LC oleogels. Then, at all
MG/LC the VO oleogels with 2% or 4% total gelator concentration
achieved higher G’ than MO oleogels. However, the presence of β crystals
will produce deleterious effects in shorter time in the VO oleogels than
in the MO oleogels. In both oils the oleogels with the highest G’ and
gel-like rheological behavior were achieved at 8.1 MG/LC, particularly
at 4% total gelator concentration. Under these conditions the β
polymorph was limited developed in the VO oleogels and completely absent
in the MO oleogels. Then, we might tailoring the rheology of MG-LC
oleogels with storage stability using as design variables the MG/LC, the
total gelator concentration, and the polarity of the oil.