Thermal and Structural Behavior of Palm Oil. Influence of Cooling Rate on Fat Crystallization |
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Authors: | Anaïs Vuillequez Lucy Koza Boulos Youssef Mathilde Bridier Jean Marc Saiter |
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Institution: | 1. Laboratoire PBS Université de Rouen / INSA de Rouen, FRE 3101, LECAP, Institut des Matériaux de Rouen. Université de Rouen, Faculté des Sciences, Avenue de l'Université BP 12, 76801 Saint Etienne du Rouvray, France;2. Nutriset, BP 35, Bois Ricard, 76770 Malaunay, France |
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Abstract: | Summary: The effects of scanning rates (q = −0.5 °C/min to −50 °C/min) on the formation of the different phases occurring at low temperature of a palm oil are investigated by means of calorimetry and optical analysis. It is demonstrated that the cooling rates changed the polymorphism of triacylglycerols (TAGs). The centrifugation is used to separate the two fractions (olein and stearin) of palm oil. We show whereas the rate of centrifugation the separation is not effective. We obtained two fractions, a liquid fraction and a solid fraction which contains some liquid TAGs. It is observed that the solid fraction of palm oil is more sensitive to the effects of the cooling rates. By changing the cooling rate q, it appears threshold behaviour for q = −3 °C/min dividing the data discussion in two parts: for slow cooling rate and for fast cooling rate. At slow cooling rates, TAGs had more time to interact. Contrary at fast cooling rate, TAGs have not the time to be reorganised in more stable conformation. Micrographs revealed that the types of crystals observed were spherolites but some variations in crystal size appeared with the variation of cooling rate. |
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Keywords: | cooling rate differential scanning calorimetry fat crystallization microstructure palm oil |
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