The structuring of vegetable oils without the use of saturated and trans fatty acids is essential for the food industry, which nowadays faces the challenge of incorporating healthy edible oils in food products. Through the molecular self-assembly of monoglycerides (MGs) we can structure highly unsaturated edible oils, developing oleogels with physical and functional properties that closely mimic those provided by saturated and trans fats. Unfortunately, MG oleogels are metastable and the polymorphic changes that occur during storage result in a deleterious effect of the oleogel's functional properties and, eventually, in oil phase separation. This chapter discusses the basic principles in the use of phase diagrams for the development of MG oleogels and their relationship with the oleogel's rheology. In the same way, this chapter presents results about the synergistic interactions of MGs with lecithin and with ethylcellulose during the development of oleogels. The oleogels formulated with MG–lecithin and MG–ethylcellulose mixtures have excellent rheological and oil-binding properties, with the additional plus of having longer term stability for oil phase separation than the MG oleogels. These results open new alternatives to diversify the use of MG oleogels in food products.
The objective of the present work was to optimize the microencapsulation conditions of neem (Azadirachta indica A. Juss) leaf extracts for the biocontrol of Tenebrio molitor. The complex coacervation method was used for the encapsulation of the extracts. The independent factors considered were the pH (3, 6, and 9), pectin (4, 6, and 8% w/v), and whey protein isolate (WPI) (0.50, 0.75, and 1.00% w/v). The Taguchi L9 (33) orthogonal array was used as the experimental matrix. The response variable was the mortality of T. molitor after 48 h. The nine treatments were applied by immersion of the insects for 10 s. The statistical analysis revealed that the most influential factor on the microencapsulation was the pH (73% of influence), followed by the pectin and WPI (15% and 7% influence, respectively). The software predicted that the optimal microencapsulation conditions were pH 3, pectin 6% w/v, and WPI 1% w/v. The signal-to-noise (S/N) ratio was predicted as 21.57. The experimental validation of the optimal conditions allowed us to obtain an S/N ratio of 18.54, equivalent to a T. molitor mortality of 85 ± 10.49%. The microcapsules had a diameter ranging from 1–5 μm. The microencapsulation by complex coacervation of neem leaf extract is an alternative for the preservation of insecticidal compounds extracted from neem leaves.
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.
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