Se ha desarrollado un sistema modelo de composición heterogénea de triacilglicéridos (TG) donde el componente de mayor temperatura de fusión cristaliza independientemente. Se emplearon, disoluciones de tripalmitina en aceite de ajonjolí (0,98,1,80 y 2,62% p/v) que siguen un comportamiento ideal de cristalización, determinado por calorimetría diferencial de barrido y la ecuación de Hildebrand, Estas disoluciones se emplearon para investigar el efecto del superenfriamiento y la viscosidad (η) en el desarrollo de los estados polimórficos de cristales de TG, su mecanismo de crecimiento, constante de velocidad de cristalización (z) y energia de activación asociada al proceso de cristalización ( E a ). La velocidad de nucleación y de crecimiento de cristales, así como la forma polimórfica desarrollada por los TG dependen predominantemente de la η y del superenfriamiento, que a su vez es función de la concentración del TG de mayor temperatura de fusión en el sistema (ej., tripalmitina). Mediante una regresión multivariable podria evaluarse el efecto conjunto del superenfriamiento, la η del medio y la concentración del componente cristalizable para predecir el tamaño, número y forma polimórfica de los cristales desarrollados durante el proceso industrial de cristalización fraccionada de aceites y grasas vegetales. Asi se establecenán las condiciones de mayor rendimiento y eficacia de separación de la fracción cristalizada.Palabras clave : Aceite de ajonjolí, cristalización, triglicéridos, tripalmitina A model system with a heterogenous composition of triacylglycerides (TG), in which the component with the highest melting temperature crystallized independently, was developed. Thus, tripalmitin solutions in sesame seed oil (0.98, 1.80 and 2.62% w/v) with ideal crystallization behavior, evaluated through differential scanning calorimetry and the Hildebrand equation, were utilized as a model system to investigate the effect of supercooling and viscosity (η) on the development of polymorph states of TG crystals, their crystal growth mechanism, crystal growth rate constant (z), and activation energy associated with the crystallization process ( E a ). Results indicated that a modification of the Avrami equation, as suggested by Khanna and Taylor, provides reliable values of z and, subsequently, correct estimates of E a . This was not the case when the original Avrami equation was used. Subsequent analysis indicated that nucleation and crystal growth, as well as the polymorph states developed by the TG, depend mainly on η and the extent of supercooling. The latter is a function of the concentration of the TG with the highest melting temperature in the system (e.g. tripalmitin). In conclusion, it is feasible to model the combined effect of supercooling, the viscosity of the liquid phase, and the concent...
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