Thermal and Structural Behavior of Milk Fat3. Influence of Cooling Rate and Droplet Size on Cream Crystallization

Lopez, Christelle; Bourgaux, Claudie; Lesieur, P.; Bernadou, Sophie; Keller, G.; Ollivon, Michel

doi:10.1016/s0021-9797(02)98548-6

Cited by 78 publications

(174 citation statements)

References 17 publications

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“…ADMF is an essential nutriment in desert areas with a complex fatty acid composition [2,5,8], which has already been discussed in the first article of this series [9]. As observed for other fats and in the previous study [9], the coupling of X-ray diffraction (XRD) as a function of temperature (XRDT) and differential scanning calorimetry (DSC) is the best technique to characterize the structural and thermal behavior of ADMF [14][15][16][17][18][19][20][21]25]. XRD permits the study of the various lamellar structures formed by triacylglycerols (TG).…”

Section: Introductionmentioning

confidence: 84%

“…Experiments were conducted using Microcalix (Centre National de la Recherche Scientifique, Châtenay-Malabry, France), an apparatus allowing simultaneous timeresolved synchrotron X-ray diffraction as a function of temperature (XRDT) and high sensitivity differential scanning calorimetry (DSC) to be carried out on the same sample, as reported previously [4,9,15,19,23]. The recording of XRDT patterns and the calibration of the detectors and the calorimeter were conducted as previously reported [4,9,10,19,23].…”

Section: Combined Xrdt and Dsc Measurementsmentioning

confidence: 99%

“…The recording of XRDT patterns and the calibration of the detectors and the calorimeter were conducted as previously reported [4,9,10,19,23]. The analysis of the XRDT patterns was performed as previously described [9,14].…”

Section: Combined Xrdt and Dsc Measurementsmentioning

confidence: 99%

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Dromedary milk fat: thermal and structural properties 2. Influence of cooling rate

Karray¹,

Lopez

Lesieur

et al. 2005

Lait

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-The crystallization behavior of anhydrous dromedary milk fat (ADMF) was examined using Microcalix (Centre National de la Recherche Scientifique, Châtenay-Malabry, France), an instrument coupling time-resolved synchrotron X-ray diffraction as a function of temperature (XRDT) at both small and wide angles and high-sensitivity differential scanning calorimetry (DSC) at an intermediate (1 °C·min -1 ) and at a fast (5 °C·min -1 ) cooling rate from 60 to -20 °C, together with their subsequent melting at 1 °C·min -1 . Upon cooling at 1 °C·min -1 , the crystallization of ADMF started at about 24 °C with the formation of a lamellar structure with a 46.9 Å period corresponding to a double-chain length molecular stacking and hexagonal chain packing (2L 1 α). From 20 °C, a major crystalline species also with double-chain lengths of 42.5 Å and orthorhombic chain packing (2L 2 β') was observed. The successive crystallizations of varieties 2L 1 and 2L 2 were correlated with the apparition of two large exothermal events recorded simultaneously by thermal analysis (DSC). However, comparison of XRDT and DSC recordings revealed the presence of a third exothermal peak probably related to a transition α → β'. At fast cooling (5 °C·min -1 ) of ADMF, three crystalline varieties were formed: the 2L 1 α (47.6 Å), 2L 2 β' (42.15 Å) and a new crystalline structure with 4 chain lengths: 4L β' of period 84.5 Å, while three endotherms were recorded by DSC. This last crystalline form which had never been characterized until now, likely corresponds to the accumulation of defects in the stable 2L β' form (42.15 Å) resulting from fast cooling and then to a local lack of symmetry in the 4L cell along the c axis of the crystals. This lack of symmetry was released during a transition 4L → 2L observed upon heating. A polymorphic transition α →β' was always observed upon ADMF heating following cooling at either 5 or 1 ° C·min -1 . Compared with the slow cooling at 0.1 °C·min -1 which was studied in the previous paper of this series, ADMF presented different structural and thermal properties. Indeed, the cooling at 1 °C·min -1 and 5 °C·min -1 generated an unstable crystalline form (α) that was not found at slow cooling at 0.1 °C·min -1 . However, the major stable form 2L β' was always observed in the three types of cooling.polymorphism / X-ray diffraction / differential scanning calorimetry / camel's milk * Corresponding author ( ): michel.ollivon@cep.u-psud.frArticle published by EDP Sciences and available at http://www.edpsciences.org/lait or http://dx

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Section: Introductionmentioning

confidence: 84%

Section: Combined Xrdt and Dsc Measurementsmentioning

confidence: 99%

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Dromedary milk fat: thermal and structural properties 2. Influence of cooling rate

Karray¹,

Lopez

Lesieur

et al. 2005

Lait

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“…Understanding of the functionality of ADMF in food products necessitates the knowledge of its physical properties. As observed for other fats, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) are the best techniques to characterize, respectively, the structural and thermal properties of ADMF [18][19][20][21][22][23][24][25]32]. Extensive descriptions of TG polymorphism based on data obtained using these techniques can be found in the literature [9,29].…”

mentioning

confidence: 99%

“…The coupling of XRD as a function of temperature (XRDT) and DSC was used to characterize the structural and thermal behaviors of pure TG [10,16], fats [15, 17, 19, 21-23, 25, 32] and dispersed systems such as natural bovine milk fat globules [18,20,23,24].…”

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confidence: 99%

Dromedary milk fat: thermal and structural properties 1. Crystalline forms obtained by slow cooling

Karray¹,

Lopez²,

Lesieur

et al. 2004

Lait

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-The thermal and structural behavior of anhydrous dromedary milk fat (ADMF) was studied by a technique that allowed simultaneous time-resolved synchrotron X-ray diffraction as a function of temperature (XRDT) and high sensitivity differential scanning calorimetry (DSC). As the camel probably represents the mammalian species best adapted to the hottest temperatures on earth as well as to harsh climatic conditions, the fatty acid composition of ADMF and its thermal properties are of special interest. In this paper, the first of a series, the crystalline organizations made by the triacylglycerols (TG) of ADMF during a slow cooling rate at |dT/dt| = 0.1 °C·min -1 are addressed. The crystalline form obtained from about 29.5 °C corresponds to a lamellar structure with a double-chain length longitudinal organization of the TG molecules (2L = 42.3 Å) associated with a β' lateral packing of the chains. The crystallization range which spreads over about 75-80°C, is similar to that observed for bovine milk fat, although the final melting temperature is higher by about 5-8 °C. DSC scans revealed the existence of up to 6 exotherms on slow cooling. A similar complex behavior was also observed on heating. PEAKFIT analysis of the XRDT individual patterns and their evolutions observed at small angles also showed the existence of additional molecular packings. However, XRDT analysis was unable to resolve individual structures. A possible epitaxy phenomenon during crystallization is discussed. Polymorphism / X-ray diffraction / differential scanning calorimetry / solid fat content / epitaxyRésumé -Propriétés thermiques et structurales de la matière grasse de lait de dromadaire. 1. Formes cristallines obtenues lors d'un refroidissement lent. Les propriétés thermiques et structurales de la matière grasse anhydre extraite du lait de dromadaire (ADMF) ont été étudiées par une nouvelle technique qui permet des mesures simultanées, sur un même échantillon, des signaux de microcalorimétrie différentielle à balayage (DSC) et de diffraction des rayons X en fonction du temps et de la température. L'étude des propriétés thermiques de la matière grasse du lait de chamelle, en relation avec sa composition, revêt un intérêt particulier si l'on considère les conditions

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The influence of pretreatment on pork fat crystallization

Svenstrup¹,

Brüggemann²,

Kristensen³

et al. 2005

Euro J Lipid Sci & Tech

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Melting points of two types of pork fat, lard and leaf fat, were studied in three different products: extracted fat, raw fat, and fat as an ingredient in liver pâté. The number of melting points and the temperature of melting were found, by differential scanning calorimetry, to correlate with the cooling rate for all of the products: Rapid cooling led to lowering of the melting point, assigned to the presence of unstable β crystals. The melting points varied also with the treatment of the fat, as the melting point of lard made by slow cooling and assigned to mainly β' crystals was different in the three products and found to be 39, 45, and 48 °C for extracted fat, raw fat, and fat as an ingredient in liver pâté, respectively, while slowly cooled leaf fat was found to have melting points at 48, 50, and 51 °C for the same three products, respectively. The fraction of unsaturated fatty acids present in the fat was important for both crystallization rate and melting points of α and β' crystals in extracted lard, an effect which was found less pronounced in liver pâté because of the presence of diverse components such as proteins.

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Thermal and Structural Behavior of Milk Fat3. Influence of Cooling Rate and Droplet Size on Cream Crystallization

Cited by 78 publications

References 17 publications

Dromedary milk fat: thermal and structural properties 2. Influence of cooling rate

Dromedary milk fat: thermal and structural properties 2. Influence of cooling rate

Dromedary milk fat: thermal and structural properties 1. Crystalline forms obtained by slow cooling

The influence of pretreatment on pork fat crystallization

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