Author(s): J.A. Solis-Fuentes | M.R. Hernandez-Medel | M.C. Duran-de-Bazua
Journal: Journal of Applied Sciences
ISSN 1812-5654
Volume: 7;
Issue: 11;
Start page: 1538;
Date: 2007;
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Keywords: Avrami equation | fat crystallization | mango almond fat | isothermal crystallization | Crystallization kinetics | Khanna and Taylor equation
ABSTRACT
In this study, the kinetics of isothermal crystallization of mango (Mangifera indica) almond seed fat var. Manila (MAF) was analyzed, within the theoretical context of the Sestak-Berggren model, the Avrami Equation and its modification by Khanna and Taylor. The results showed that the induction times for the formation of crystalline nuclei increased with the crystallization temperature (3.3 min at 8�C and 10.9 min at 12�C). The supercooling level notably influenced the MAF crystallization rate, since the global constant of crystallization rate, Z, grew 3.3 times from 12 to 8�C (for fractions of fat solids between 0.25 and 0.75, Z was 0.2904, 0.1584 and 0.0879 min-1 at 8, 10 and 12�C, respectively) and the Avrami parameter r was higher than 4; this demonstrates the effect of fat system complexity due to its multi-component nature and the heterogeneous character of this crystallization process, which includes additional participation of nucleation sites. The modified model by Khanna and Taylor provided better parametral values than the other two studied for explaining MAF crystallization kinetic.
Journal: Journal of Applied Sciences
ISSN 1812-5654
Volume: 7;
Issue: 11;
Start page: 1538;
Date: 2007;
VIEW PDF
DOWNLOAD PDF Original pageKeywords: Avrami equation | fat crystallization | mango almond fat | isothermal crystallization | Crystallization kinetics | Khanna and Taylor equation
ABSTRACT
In this study, the kinetics of isothermal crystallization of mango (Mangifera indica) almond seed fat var. Manila (MAF) was analyzed, within the theoretical context of the Sestak-Berggren model, the Avrami Equation and its modification by Khanna and Taylor. The results showed that the induction times for the formation of crystalline nuclei increased with the crystallization temperature (3.3 min at 8�C and 10.9 min at 12�C). The supercooling level notably influenced the MAF crystallization rate, since the global constant of crystallization rate, Z, grew 3.3 times from 12 to 8�C (for fractions of fat solids between 0.25 and 0.75, Z was 0.2904, 0.1584 and 0.0879 min-1 at 8, 10 and 12�C, respectively) and the Avrami parameter r was higher than 4; this demonstrates the effect of fat system complexity due to its multi-component nature and the heterogeneous character of this crystallization process, which includes additional participation of nucleation sites. The modified model by Khanna and Taylor provided better parametral values than the other two studied for explaining MAF crystallization kinetic.