Étude du Polymorphisme et de L'Intersolubilité de Triglycerides Palmito‐Oleiques par Diffraction RX de Poudres et Analyse Calorimétrique Différentielle

Abstract

The study of the polymorphism and the intersolubility of some palmitic P and oleic 0 triglycerider : PPP, OPP and POO, has been performed using differential scanning calorimetry and powder X-ray diffraction. Binary and ternary phase diagrams have been constructed by differential scanning calorimetry; the different polymorphic forms have been verified by variable temperature X-ray powder diffraction. Each system has been studied by two ways : after melting and quenching, and after tempering a few months at room temperature. The construction of those phase diagrams shows the formation of solid solutions, monotectic interactions ..., according to the nature and the polymorphic form of the triclycerides.

Binary Mixtures of Tripalmitoylglycerol (PPP) and 1,3‐Dipalmitoyl‐2‐stearoyl‐sn‐glycerol (PSP): Polymorphism and Kinetic Phase Behavior

“…Bouzidi and Narine found the same phenomenon when they studied the binary mixture of SSS and PSS, in which they concluded that the growth of the β‐phase was primarily prevented by PSS. Because β′ PSP is the most favorable form of PSP and knowing that β PSP is very unlikely to exist, it could be proposed that the PSP is a β′ promoter and also a β suppressor in PPP at relatively low levels, which was supported by XRD data that showed only β′‐form in mixture containing X PSP > 0.3. The polymorphic transitions were influenced by the kinetic effect of both cooling and heating rate, but not to the extent of changing the sequence of the transitions.…”

“…Mixtures X PSP = 0.3–0.4 also showed the same behavior, but the transformation is less pronounced than the mixtures containing higher amounts of PSP. Gibon et al studied the phase behavior and intersolubility of different trisaturated TAGs and mixtures thereof and found that after very long storage period the stable form of PSP was β′ 1 ‐2. At 50 °C, the PPP–PSP system crystallized in the unstable β′ 2 ‐2 form, which transformed, after tempering into β′ 1 ‐2 solid solution.…”

Solid phase behavior of mixture systems based on tripalmitoyl glycerol and monounsaturated triacylglycerols forming a molecular compound

“…These results contrast with previous data on PPP/PPO mixtures quenched from the melt at 25 °C min −1 to −40 °C and subsequently heated at 5 °C min −1 . 20 Accordingly, sub-α solid solutions were formed in mixtures with PPO above 30%, which during heating sequentially transformed into α and β′ solid solutions until phase separation occurred. The divergent behavior of PPP/PPO mixtures in the present study was attributed to the much lower rate applied during the cooling treatment.…”

“…It is worth noting that compared to the extensive research conducted on PPP/POP mixtures under several experimental approaches, 16–19 little data is available on the binary phase behavior of PPP and PPO. 20 Moreover, to the best of our knowledge, no detailed phase behavior studies on ternary mixtures including PPP, POP, and PPO have been carried out yet. A fundamental look into the polymorphism and solid-state miscibility of these systems may help expand the understanding of the mixing interactions that contribute to the crystallization behavior of fats like palm oil, in which the former TAGs represent primary high-melting components.…”

Systematic Investigation of Co-Crystallization Properties in Binary and Ternary Mixtures of Triacylglycerols Containing Palmitic and Oleic Acids in Relation with Palm Oil Dry Fractionation

“…The data available in the literature relating to systems containing palmitic and oleic acids are summarized below. Gibon et al compared PPP/PSP and PPP/POP binary systems, focusing on the influence of fatty acid unsaturation (stearic vs. oleic) [ 19 , 20 , 21 ]. Minato et al reported some structural aspects with the use of synchrotron X-ray radiation [ 22 ]; they claimed that the PPP/POP system shows immiscible monotectic properties in both metastable and stable forms, while Gibon et al reported that the metastable forms were partly miscible.…”