We investigated the shearing effect in the thermo-mechanical properties of candelilla wax (CW) and candelilla wax-tripalmitin (CW-TP) organogels developed using safflower oil as the liquid phase. A shear rate of 600 s −1 was applied during cooling (1°C/min) of 3% CW and 3% CW-1% TP solutions, until reaching nucleation (i.e., 47°C) or metastable conditions (i.e., 52°C) then allowing the development of the organogel under quiescent conditions at 15°C. The thermal and rheological properties of these organogels were compared with the ones of organogels developed under static conditions. The X-ray results showed that under static conditions the CW crystallized in an orthorhombic O ? ð Þ subcell packing with a lateral stacking with a length (L) equivalent to the hydrocarbon chain's length. During organogelation of the 3% CW-1% TP solution, CW and TP co-crystallized in a O ? subcell packing with TP in a 2L stacking organization. The application of shearing did not modify the molecular packing of the crystals or the melting properties of the organogels. However, the CW and CW-TP organogels developed with shearing showed the formation of larger crystals (i.e., fiber-like or plate-like) in comparison with the ones developed under static conditions. The presence of 1% TP increased the solid fat content, and thus the CW-TP organogels showed higher elasticity (G′) than CW organogels. The organogels developed with the application of shearing until reaching metastable conditions (i.e., CW 52°C and CW-TP 52°C) had the highest G′ and yield stress of all organogels investigated. In the same way, creep and recovery analyses showed that CW 52°C and CW-TP 52°C organogels had the highest resistance to deformation, lowest instantaneous recovery, and highest extended recovery of all organogels studied. We concluded that application of shear and the extent of its application as a function of supercooling determine crystal size and the proportion of transient to junction zones throughout the three-dimensional crystal network and, therefore, the organogels' rheological properties.

No abstract

No abstract

Saturated alkyl esters play an important role in determining the functional properties of the vegetable waxes used in the formulations of natural cosmetics and edible oleogels. We studied the relationship between the thermo-mechanical properties and crystal microstructure developed by saturated symmetrical (

We studied the molecular self-assembly of commercial and pure-saturated and pure-unsaturated phosphatidylcholine (PtdCho) in vegetable (VO) and mineral (MO) oils. The PtdCho self-assembly was monitored through rheology, differential scanning calorimtery (DSC), and polarized light microscopy. The results showed that in the presence of just the constituent water, the PtdCho selfassembly occurred through the formation of a "liquid structure" stabilized by electrostatic interactions. The DSC measurements did not evidence the development of the "liquid structure." However, the phase shift angle (δ) measured by rheology closely followed the PtdCho self-assembly in both oils. The kinetics of the PtdCho self-assembly and the crystal habit developed depended on the PtdCho solubility in the oil, the PtdCho purity, and the extent of unsaturation. Thus, the saturated PtdCho crystallized in the VO developing an organization of intertwined crystals that resulted in organogels with a true-gel behavior (G 0 of 12.2 × 10 5 to 16 × 10 5 Pa). In the MO, the saturated PtdCho crystallized in smaller microstructures developing organogels with higher G 0 , particularly with the commercial PtdCho (i.e., G 0 of 32 × 10 5 Pa). With the unsaturated PtdCho, the presence of cis unsaturations favored the formation of inverted micelles in the VO and MO organogels. Thus, in contrast to the saturated PtdCho organogels, the unsaturated PtdCho organogels had lower G 0 (30 × 10 2 to 45 × 10 2 Pa) with a gel-like behavior.