Molecular Arrangement in Glycerides

Larsson, Karl-Johan

doi:10.1002/lipi.19720740302

Cited by 180 publications

(117 citation statements)

References 24 publications

Supporting

Mentioning

110

Contrasting

Unclassified

Order By: Relevance

“…Evolutions of XRD patterns with time allow the determination of the phase transitions occurring in the sample. For instance, in both cream and AMF samples the first diffraction peak formed at wide angles at q = 1.52 Å -1 (4.13 Å), on the top of a broad peak centered at q = 1.43 Å -1 (4.4 Å) corresponding to the lateral packing of TG chains in the liquid state [12], is the unstable polymorphic variety α (Figs. 1a, 1b, inserts).…”

Section: Isothermal Evolution At 4 O C After Quenchingmentioning

confidence: 99%

Crystalline structures formed in cream and anhydrous milk fat at 4 °C

Lopez

Bourgaux

Lesieur

et al. 2002

Lait

View full text Add to dashboard Cite

-Crystallization and polymorphic evolutions of triacylglycerols (TG), at 4 o C, in cream and anhydrous milk fat (AMF) samples were studied using high-sensitivity differential scanning calorimetry (DSC), time-resolved synchrotron X-ray diffraction (XRD) and density measurement, and compared as a function of time after quenching from 60 to 4 o C. The evolution of the two crystalline structures initially formed in both samples, corresponding to a metastable 2L (47 Å) and a 3L (70.5 Å) lamellar organization with hexagonal chain packings (α form), were monitored in isothermal conditions at 4 o C as a function of time t. For t > 15 min, short spacings showed the formation of a β' packing of the chains in coexistence with the α form. In AMF, the occurrence of some β form was also recorded. For long spacings, a 2L (39 Å) structure was formed in cream with the 3L (70.5 Å) structure still being preponderant after conditioning for 30 min at 4 o C. In AMF samples, a TG polymorphic transition 3L (70.5 Å) → 2L (39 Å) + 3L (66 Å), correlated with an exothermic peak recorded simultaneously by DSC, was clearly visible. At t > 100 h conditioning at 4 o C, the same crystalline structures were found in cream and AMF with the coexistence of at least a 2L (40.5 Å) and a 3L (54.2 Å) longitudinal organization, associated with α, β' 2 , β' 1 and β packings of the chains. The melting behaviors of cream and AMF were monitored on heating at 2 o C . min -1 by coupled XRD as a function of temperature and DSC experiments. The absence of further structural evolution and polymorphic transition until final melting demonstrates the relative stability of the structure formed. The evolution of cream density after quenching to 4 o C revealed two transitions, the amplitudes, rates and duration of which coincided with DSC and XRD experiments. All data are in agreement in demonstrating that two transitions, a fast and a slow one, occur in dairy products after fast cooling to 4 o C. Cristallisation / polymorphisme / triacylglycérol / diffraction des rayons X / calorimétrie

show abstract

Section: Isothermal Evolution At 4 O C After Quenchingmentioning

confidence: 99%

Crystalline structures formed in cream and anhydrous milk fat at 4 °C

Lopez

Bourgaux

Lesieur

et al. 2002

Lait

View full text Add to dashboard Cite

show abstract

“…For example, the smectic model by Larsson and the nematic one by Cebula are representative. [12][13][14][15]17 The former suggests the existence of a para-lamellar conformation based on XRD, DSC and Raman measurements. The latter suggests that no lamellar conformation is present based on neutron scattering.…”

Section: Resultsmentioning

confidence: 99%

“…ordered structures of molecules in melts. [12][13][14][15][16] Such melts are important to control the polymorphs as well as the speed and quality of the crystallization toward a desired crystalline form. However, due to a general difficulty to determine the local structures in melts under a phase transition between crystalline phases, clarifying the local structures in melts remains a challenging issue to be solved for various types of TAGs.…”

Section: Introductionmentioning

confidence: 99%

α-Melt Structure of l,3-Dipahnitoyl-2-oleoyl-sn-glycerol (POP) under a Thermal Thawing Process Studied by Infrared Spectroscopy

Yui

Morisaku

2017

ANAL. SCI.

View full text Add to dashboard Cite

“…The three main types of polymorphic crystal forms in TG are the alpha (D), beta prime (E') and beta (E) forms, in the order of their increasing stability. They have been related to different subcells some of them have been described in detail [14][15][16][17][18][19][20][21][22][23] Transitions between these three major polymorphic varieties are irreversible. Monotropism implies that they are only possible via a liquid and when leading to the formation of more stable species.…”

Section: -P2mentioning

confidence: 99%

Characterization of Lipid Nanostructures using DSC coupled to SAXS and WAXS

Kalnin¹

2009

XXXV JEEP – 35th Conference on Phase Equilibria

View full text Add to dashboard Cite

Lipids are self-assembling molecules responsible for compartment formation in animal cells. Beside bilayer membranes, they also form all kind of aggregates and mesophases thank to their aptitude to modulate interface curvature. The characterization of the internal structure of such systems is complex and requires the use of combined techniques. Up to recently, droplet size, dilution and complexity prevented any direct identification of the crystalline varieties formed by triacylglycerols inside emulsion globules. Crystallization within this submicron droplets can now be conveniently monitored using Synchrotron X-ray diffraction coupled with DSC. Crystal forms and polymorphism can be influenced by different factors and here we focus on influence factors for crystallization kinetics of emulsified lipids.

show abstract

Molecular Arrangement in Glycerides

Abstract: Die Wichtigkeit einer mechanischen Bearbeitung der MCT-Margarine wahrend der Herstellung wird aus Abb. 4 deutlich.

Cited by 180 publications

References 24 publications

Crystalline structures formed in cream and anhydrous milk fat at 4 °C

Crystalline structures formed in cream and anhydrous milk fat at 4 °C

α-Melt Structure of l,3-Dipahnitoyl-2-oleoyl-sn-glycerol (POP) under a Thermal Thawing Process Studied by Infrared Spectroscopy

Characterization of Lipid Nanostructures using DSC coupled to SAXS and WAXS

Contact Info

Product

Resources

About