Anhydrous Goat's Milk Fat:  Thermal and Structural Behaviors Studied by Coupled Differential Scanning Calorimetry and X-ray Diffraction. 2. Influence of Cooling Rate

Abstract

Crystallization and melting properties of triacylglycerols (TGs) in anhydrous goat's milk fat (AGMF) are investigated by X-ray diffraction as a function of temperature (XRDT) coupled with high-sensitivity differential scanning calorimetry (DSC), using synchrotron radiation and Microcalix. The polymorphic behavior of AGMF was monitored by varying the cooling rates between 5 and 1 degrees C/min from 45 to -20 degrees C with their subsequent melting at 1 degrees C/min. Quenching of AGMF at -20 degrees C was also examined to determine the metastable polymorphic form of AGMF. At intermediate cooling rates, TGs in AGMF crystallize, from about 18 degrees C in two different lamellar structures with triple chain length 3Lalpha stacking of 72 A and a double chain length 2Lalpha stacking of 48 A, which are correlated to two overlapped exothermic peaks recorded by DSC. A reversible transition sub alpha <--> alpha was observed. Subsequent heating at 1 degrees C/min shows numerous structural rearrangements before final melting. At fast cooling of AGMF (5 degrees C/min), similar unstable crystalline varieties are formed while three endotherms are recorded. Several new unstable lamellar structures are observed after quenching. All of these data are compared to those previously reported at slow cooling (0.1 degrees C/min) showing a relative stability of the structures formed. In spite of general similitude, the thermal and structural behavior of the goat's milk is more complex than that of the cow's milk.

The Unique Crystallization Behavior of Buffalo Milk Fat

“…The types of TAGs and fatty acids in milk fat depend on the season and the geographical regions where cows are grown, , and these variations, albeit small, can strongly affect crystallization behavior. , Compositional differences in milk fats obtained from different animals (e.g., buffalo vs cow) are more significant than variation within the same species. , Those differences are currently not fully characterized, but they could have a significant effect on the crystallization and melting behavior of milk fat, as shown by a small number of crystallization studies carried out on nonbovine milk fat, such as goat and camel. − …”

Transparent Dispersions of Milk-Fat-Based Nanostructured Lipid Carriers for Delivery of β-Carotene

“…β-Carotene showed several sharp peaks, indicating crystallinity, while AMF possesses smaller and broader peaks, indicating that AMF has mixed morphology at room temperature. It has previously been suggested that amorphous morphology is dominant, but the crystalline structure is also present in AMF at room temperature . For NLCs loaded with β-carotene, because Tween 80 is a noncrystalline compound at ∼20 °C, − the smooth XRD curve of the β-carotene-loaded NLCs and its similarity to the spectrum of AMF suggest that β-carotene was embedded in NLCs .…”

“…It has previously been suggested that amorphous morphology is dominant, but the crystalline structure is also present in AMF at room temperature. 37 For NLCs loaded with β-carotene, because Tween 80 is a noncrystalline compound at ∼20 °C, 38−40 the smooth XRD curve of the β-carotene-loaded NLCs and its similarity to the spectrum of AMF suggest that β-carotene was embedded in NLCs. 41 Detailed structures of AMF crystals however were not studied in the present work, because it requires temperaturecontrolled small-angle XRD.…”

Shea butter solid nanoparticles for curcumin encapsulation: Influence of nanoparticles size on drug loading

“…A). The chain packing is deduced from the repetition distance corresponding to the first reflections observed at small angle (double‐chain length 2L: 40–45 Å and triple‐chain length 3L: ∼60 Å) . These configurations depended on the fatty acid composition of the lipid mixture.…”