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Molecules 2013, 18(1), 1036-1052; doi:10.3390/molecules18011036
Article

Comparative Analysis of Thermal Behavior, Isothermal Crystallization Kinetics and Polymorphism of Palm Oil Fractions

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Received: 5 November 2012; in revised form: 31 December 2012 / Accepted: 7 January 2013 / Published: 15 January 2013
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Abstract: Thermal behavior of palm stearin (PS) and palm olein (PO) was explored by monitoring peak temperature transitions by differential scanning calorimetry (DSC). The fatty acid composition (FAC), isothermal crystallization kinetics studied by pulsed Nuclear Magnetic Resonance (pNMR) and isothermal microstructure were also compared. The results indicated that the fatty acid composition had an important influence on the crystallization process. PS and PO both exhibited more multiple endotherms than exotherms which showed irregular peak shapes. An increasing in cooling rate, generally, was associated with an increase in peak size. Application of the Avaimi equation to isothermal crystallization of PS and PO revealed different nucleation and growth mechanisms based on the Avrami exponents. PS quickly reached the end of crystallization because of more saturated triacylglycerol (TAG). The Avrami index of PS were the same as PO under the same isothermal condition at lower temperatrue, indicating that the crystallization mechanism of the two samples based on super-cooling state were the same. According to the polarized light microscope (PLM) images, crystal morphology of PS and PO was different. With the temperature increased, the structure of crystal network of both PS and PO gradually loosened.
Keywords: fractional crystallization; thermal behavior; isothermal crystallization kinetics; polymorphism fractional crystallization; thermal behavior; isothermal crystallization kinetics; polymorphism
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Zhang, X.; Li, L.; Xie, H.; Liang, Z.; Su, J.; Liu, G.; Li, B. Comparative Analysis of Thermal Behavior, Isothermal Crystallization Kinetics and Polymorphism of Palm Oil Fractions. Molecules 2013, 18, 1036-1052.

AMA Style

Zhang X, Li L, Xie H, Liang Z, Su J, Liu G, Li B. Comparative Analysis of Thermal Behavior, Isothermal Crystallization Kinetics and Polymorphism of Palm Oil Fractions. Molecules. 2013; 18(1):1036-1052.

Chicago/Turabian Style

Zhang, Xia; Li, Lin; Xie, He; Liang, Zhili; Su, Jianyu; Liu, Guoqin; Li, Bing. 2013. "Comparative Analysis of Thermal Behavior, Isothermal Crystallization Kinetics and Polymorphism of Palm Oil Fractions." Molecules 18, no. 1: 1036-1052.



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