Solid phase behavior of mixture systems based on tripalmitoyl glycerol and monounsaturated triacylglycerols forming a molecular compound (original) (raw)
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Mixing Phase Behavior of Tripalmitin and Oleic-Rich Molecular Compound-Forming Triacylglycerols
Industrial & Engineering Chemistry Research, 2021
The binary phase behavior of triacylglycerol (TAG) mixtures constituted by PPP (tripalmitin) and either POP (1,3-dipalmitoyl-2-oleoyl-glycerol), OPO (1,3-dioleoyl-2-palmitoyl-glycerol), or MCPOP/OPO (molecular compound formed by POP/OPO at a 1:1 concentration ratio) was determined by differential scanning calorimetry (DSC), synchrotron (SR-) and laboratory-scale X-ray diffraction (XRD). Steric hindrance due to saturated-unsaturated acyl chain interactions and differences in the thermal stability of TAGs seemed to dictate the independent polymorphic crystallization and transformation observed under kinetic conditions, as well as the very asymmetric eutectic-type phase diagrams obtained from the study of thermodynamically stabilized PPP/POP, PPP/OPO, and PPP/MCPOP/OPO mixtures. Moreover, the solid integration determined for MCPOP/OPO in the βPPP crystalline phase (20-25%), halfway between that of OPO (<5%) and POP (30-35%), showed the ability of molecular compounds to tune the thermophysical properties of fat systems. This highlights the impact that molecular compoundforming TAGs may have on the efficient industrial separation of lipids, and suggest their potential applicability in the development of edible fat blends with tailored functionalities.
European Journal of Lipid Science and Technology, 2010
In this study, the crystallization and melting properties of four different fat blends with the same saturated fat content (30%) but with different ratios of symmetric and asymmetric monounsaturated triacylglycerols were investigated using pNMR, DSC and polarized light microscopy. Blends were either palmitic (P) or stearic (S) based, and were combinations of SatOSat-rich (Sat = saturated, O = oleic) and SatSatO-rich vegetable oils with high-oleic sunflower oil. The DSC results demonstrate that there was almost no difference in crystallization mechanism and crystallization rate between the two P-based blends. Both blends showed a two-step crystallization, which can be explained by polymorphism. Stop-and-return DSC results suggested an initial crystallization into an unstable polymorph followed by polymorphic transition during the crystallization. For the S-based blends there was a clear difference between the SOS-rich and the SSO-rich blend, with a slower crystallization for the SSO-rich blend. Possibly, this can be explained by fractional crystallization. The microstructure did not differ greatly between the blends. Directly after crystallization, the crystals of the SSO-rich blend were slightly larger than the crystals of the SOS-rich blend.
Solid−Liquid Equilibrium of Saturated Fatty Acids + Triacylglycerols
Journal of Chemical & Engineering Data, 2010
Phase diagrams of tricaprylin (1,3-di(octanoyloxy)propan-2-yl octanoate) + myristic acid (tetradecanoic acid), commercial triolein + palmitic acid (hexadecanoic acid), and trilinolenin (propane-1,2,3-triyl tris[(9Z,12Z,15Z)-octadeca-9,12,15-trienoate]) + stearic acid (octadecanoic acid) were obtained by differential scanning calorimetry (DSC). The occurrence of an eutectic point very close to the pure triacylglycerol can be assumed in all of the three investigated systems. The liquid phase was modeled using Margules twosuffix, Margules three-suffix, nonrandom two-liquid (NRTL), and universal quasichemical functional group activity coefficient (UNIFAC) Dortmund models. The best modeling results were obtained using the NRTL model. The UNIFAC Dortmund model describes the multicomponent system containing commercial triolein + palmitic acid well.
An Insight into the Solid-State Miscibility of Triacylglycerol Crystals
Molecules, 2020
The crystallization properties of triacylglycerols (TAGs) strongly determine the functional properties of natural lipids. The polymorphic and mixing phase behavior of TAG molecules have long been, and still are, a hot topic of research with special relevance for the cosmetic, pharmaceutical, and food industry. To avoid the difficulties arising from the study of whole real fats, studies at the molecular level on mixtures of a limited number of TAGs has become an indispensable tool to identify the underlying causes of the physical properties in lipid systems. In particular, phase diagrams of binary mixtures of TAGs exhibiting a different degree of heterogeneity (monoacid or mixed fatty acids; molecular symmetry; the presence of cis or trans double bonds) have resulted in a significant breakthrough in our knowledge about structure–interaction–function relationships. The present work aims to provide an overview of the main reports regarding binary and ternary TAG systems, from the early...
Phase behaviour of model triglyceride ternary blends: triolein, tripalmitin and tristearin
Physical Chemistry Chemical Physics, 2022
We investigate the phase behavior of model ternary triacylglycerol blends, comprising triolein (C 57 H 104 O 6 , OOO), tripalmitin (C 51 H 98 O 6 , PPP) and tristearin (C 57 H 110 O 6 , SSS), building upon extensive characterisation of single and binary mixtures, in order to rigorously map the thermal transitions of model natural 'fats'. A combination of calorimetry, X-ray diffraction, and FTIR spectroscopy, is employed to determine crystallisation and melting temperatures and identify corresponding phases in the complex ternary systems. We recover the eutectic behaviour of SSS-PPP blends and the invariability of OOO neat transitions, and resolve the complex β ′ + β ternary surface, reflecting the roles of unsaturation and polymorphism of its constituents. Our results provide a representation of the OOO:PPP:SSS:temperature phase behaviour into a triangular prism, consistent with binary pair-wise data, which can inform a range of food science, cosmetic, pharmaceutical and cleaning applications that depend strongly on the physical-chemistry of such multicomponent 'triglycerides'.
Grasas y Aceites
A calculation procedure for formulating lauric and palmitic fat blends has been developed based on grouping TAG melting points. This procedure offered more flexibility in choosing the initial fats and oils and eventually gave deeper insight into the existing chemical compositions and better prediction on the physicochemical properties and microstructure of the fat blends. The amount of high, medium and low melting TAGs could be adjusted using the given calculation procedure to obtain the desired functional properties in the fat blends. Solid fat contents and melting behavior of formulated fat blends showed particular patterns with respect to ratio adjustments of the melting TAG groups. These outcomes also suggested that both TAG species and their quantity had a significant influence on the crystallization behavior of the fat blends. Palmitic fat blends, in general, were found to exhibit higher SFC values than those of Lauric fat blends. Instead of the similarity in crystal microstru...
2016
Complex pseudo-ternary phase diagrams based on sucrose monolaurate (SE), propylene glycol (PG) and various phospholipids (PL) as the ?surfactant phase?; triacetin (TA) and decaglycerol ester (10G1CC) as the ?oil phase? and water as the aqueous phase were constructed into which we solubilized water insoluble bioactives. In this study we examined the relationship between the chemical characteristics of the drugs and the type of the PL using DLS, viscosity, electrical conductivity, SAXS, SD-NMR and cryo-TEM measurements. It was found that: 1) the system remains micellar after aqueous dilution but with higher polydispersity and shapes. We concluded that the structures in the absence of water (but in the presence of PG) were of direct spherical micelles (~4 nm) mixed with elongated cylindrical micelles (12?120 nm); 2) the aqueous dilution causes fragmentation of the cylinders into smaller spherical micelles; 3) solubilization of NaDFC behaving like kosmotropic agent or ?structure-maker? ...
On the solid–liquid equilibrium of binary mixtures of fatty alcohols and fatty acids
Fluid Phase Equilibria, 2014
Fatty alcohols and fatty acids are used in the cosmetic, pharmaceutical and food industries as surfactants. They are also considered phase change materials for thermal storage processes. Information on their thermal properties is required for optimizing production processes as well as for improving their industrial and home use. In the present study, the solid-liquid phase diagrams of three binary systems of 1-tetradecanol + dodecanoic acid, 1-hexadecanol + tetradecanoic acid and 1-octadecanol + hexadecanoic acid were determined by differential scanning calorimetry. The phase-transition phenomena were further investigated by optical micrographs and X-ray diffraction patterns. The experimental data showed that the systems present eutectic transitions and some of them exhibit partial solid phase miscibility. The liquid phase activity coefficients were calculated by Margules 2 and 3-suffix and by UNIFAC and UNIFAC-Dortmund methods. The modeling approach resulted in an accurate prediction, with average absolute deviations from experimental data lower than 1.16 K. The values of excess Gibbs free energy present an unusual behavior, with positive deviations at very low alcohol concentrations and negative ones at high concentrations of this component. This occurs due to changes in the H-bonding interactions along the concentration range of the mixture.
2011
Thermal properties for pure fatty acids and its mixtures were analyzed by differential scanning calorimetry (DSC). Solid-liquid and liquid-solid phase transitions were observed on heating and cooling curves. Results of melting temperature and enthalpy of melting for pure palmitic acid were in good agreement with the majority of the published values. For pure oleic acid, a reversible solid-solid phase transition from γ to α phase was observed on the heating curve. For ternary mixtures containing palmitic acid, oleic acid and n-decane, solid-liquid and liquid-solid phase transitions result from the quantities of fatty acids in the mixtures, while n-decane dose not affect the phase transition at the analyzed temperature range. Keyword: Differential scanning calorimetry, Palmitic acid, Oleic acid, Phase transition, Melting temperature, Crystallization temperature, Fatty acids
X-ray diffraction study of cholesterol-cholesteryl oleate binary mixtures
1987
The phase transitions for binary mixtures of cholesteryl oleate (CO) and cholesterol (CH) have been investigated by X-ray diffraction, differential scanning calorimetry and optical microscopy. The phase diagrams on heating, involving the solid-solid and solid-isotropic liquid transitions, and on cooling, involving the cholesterie and smectic mesophases, have been derived. In particular, a strong supercooling effect of liquid cholesterol and a progressive decrease of the isotropic liquid-cholesterie and cholesterie-smectic transition temperatures were observed. Moreover, some structural modifications induced in the smcctic A and in the cholesteric phase by the presence of CH in CO were detected. Finally the dependence of intermolecular distance in the isotropic liquid phase was studied as a function of temperature and mixture composition.