Anhydrous Goat's Milk Fat: Thermal and Structural Behaviors Studied by Coupled Differential Scanning Calorimetry and X-ray Diffraction. 2. Influence of Cooling Rate
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- 作者：Wafa Ben Amara-Dali ; Pierre Lesieur ; Franck Artzner ; Nadia Karray ; Hamadi Attia ; Michel Ollivon
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2007
- 出版时间：June 13, 2007
- 年：2007
- 卷：55
- 期：12
- 页码：4741 - 4751
- 全文大小：754K
- 年卷期：v.55,no.12(June 13, 2007)
- ISSN：1520-5118
文摘
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-sensitivitydifferential scanning calorimetry (DSC), using synchrotron radiation and Microcalix. The polymorphicbehavior of AGMF was monitored by varying the cooling rates between 5 and 1 
C/min from 45 to-20 C with their subsequent melting at 1 C/min. Quenching of AGMF at -20 C was also examinedto determine the metastable polymorphic form of AGMF. At intermediate cooling rates, TGs in AGMFcrystallize, from about 18 C in two different lamellar structures with triple chain length 3L
stackingof 72 Å and a double chain length 2L stacking of 48 Å, which are correlated to two overlappedexothermic peaks recorded by DSC. A reversible transition sub 
was observed. Subsequentheating at 1 C/min shows numerous structural rearrangements before final melting. At fast coolingof AGMF (5 C/min), similar unstable crystalline varieties are formed while three endotherms arerecorded. Several new unstable lamellar structures are observed after quenching. All of these dataare compared to those previously reported at slow cooling (0.1 C/min) showing a relative stability ofthe structures formed. In spite of general similitude, the thermal and structural behavior of the goat'smilk is more complex than that of the cow's milk.
C/min from 45 to-20 C with their subsequent melting at 1 C/min. Quenching of AGMF at -20 C was also examinedto determine the metastable polymorphic form of AGMF. At intermediate cooling rates, TGs in AGMFcrystallize, from about 18 C in two different lamellar structures with triple chain length 3L stackingof 72 Å and a double chain length 2L stacking of 48 Å, which are correlated to two overlappedexothermic peaks recorded by DSC. A reversible transition sub was observed. Subsequentheating at 1 C/min shows numerous structural rearrangements before final melting. At fast coolingof AGMF (5 C/min), similar unstable crystalline varieties are formed while three endotherms arerecorded. Several new unstable lamellar structures are observed after quenching. All of these dataare compared to those previously reported at slow cooling (0.1 C/min) showing a relative stability ofthe structures formed. In spite of general similitude, the thermal and structural behavior of the goat'smilk is more complex than that of the cow's milk.