Efecto de temperatura y tiempo de calentamiento en variables termodinámicas de cinética de vitamina C en pulpa diluida de caqui (Diospyros caqui L. f.)
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Date
2025
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Universidad Nacional de Trujillo
Abstract
Evaluar la cinética de la vitamina C durante el tratamiento térmico es crucial para optimizar el proceso, preservando su valor nutricional y las propiedades sensoriales de un zumo o jugo. Por tanto, este trabajo de investigación tuvo como objetivo evaluar el efecto de temperatura (75, 80 y 85 °C) y tiempo de calentamiento (5 – 60 min) en variables termodinámicas (constante k, energía de activación, entalpia de activación, energía libre de Gibbs y entropía de activación) de la cinética de vitamina C en pulpa diluida de caqui (Diospyros caqui L. f.). Para ello, la pulpa de caqui fue diluida con agua destilada en proporción 1:2. A continuación se sometió a tratamiento térmico monitoreando cada 5 minutos la concentración de vitamina C, hasta llegar a 60 minutos. Los resultados mostraron que la vitamina C disminuye su concentración en función al tiempo, presentando una cinética de primer orden con valores de constante cinética de deterioro (k) de -4.653, -6.708 y 10.071 x 10-3 min-1, a 75, 80 y 85 °C, respectivamente. La energía de activación (Ea) se calculó en 80.04 kJ/mol, la entalpía de activación (ΔH) en 79.06 kJ/mol y la entropía de activación (ΔS) en -0.062 kJ/mol.K. La energía libre de Gibbs (ΔG) fue de 100.59, 100.9 y 101.21 kJ/mol para 75, 80 y 85 °C respectivamente; estos valores positivos indicaron que la degradación de la vitamina C fue no espontáneo. Al final del proceso, se concluye que la temperatura afecta significativamente (p < 0.05) a la constante k para la vitamina C en el tratamiento térmico de la pulpa diluida de caqui.
ABSTRACT Evaluating the kinetics of vitamin C during heat treatment is crucial to optimize the process, preserving its nutritional value and the sensory properties of a juice. Therefore, this research work aimed to evaluate the effect of temperature (75, 80 and 85 °C) and heating time (5 – 60 min) on thermodynamic variables (k constant, activation energy, activation enthalpy, Gibbs free energy and activation entropy) of the kinetics of vitamin C in diluted persimmon pulp (Diospyros caqui L. f.). For this purpose, the persimmon pulp was diluted with distilled water in a 1:2 ratio. It was then subjected to heat treatment monitoring the concentration of vitamin C every 5 minutes, until reaching 60 minutes. The results showed that vitamin C decreased its concentration as a function of time, presenting a first-order kinetics with values of kinetic constant of deterioration (k) of -4.653, -6.708 and 10.071 x 10-3 min-1, at 75, 80 and 85 °C, respectively. The activation energy (Ea) was calculated at 80.04 kJ/mol, the activation enthalpy (ΔH) at 79.06 kJ/mol and the activation entropy (ΔS) at -0.062 kJ/mol.K. The Gibbs free energy (ΔG) was 100.59, 100.9 and 101.21 kJ/mol for 75, 80 and 85 °C respectively; these positive values indicated that the degradation of vitamin C was non-spontaneous. At the end of the process, it is concluded that temperature significantly affects (p < 0.05) the constant k for vitamin C in the thermal treatment of diluted persimmon pulp.
ABSTRACT Evaluating the kinetics of vitamin C during heat treatment is crucial to optimize the process, preserving its nutritional value and the sensory properties of a juice. Therefore, this research work aimed to evaluate the effect of temperature (75, 80 and 85 °C) and heating time (5 – 60 min) on thermodynamic variables (k constant, activation energy, activation enthalpy, Gibbs free energy and activation entropy) of the kinetics of vitamin C in diluted persimmon pulp (Diospyros caqui L. f.). For this purpose, the persimmon pulp was diluted with distilled water in a 1:2 ratio. It was then subjected to heat treatment monitoring the concentration of vitamin C every 5 minutes, until reaching 60 minutes. The results showed that vitamin C decreased its concentration as a function of time, presenting a first-order kinetics with values of kinetic constant of deterioration (k) of -4.653, -6.708 and 10.071 x 10-3 min-1, at 75, 80 and 85 °C, respectively. The activation energy (Ea) was calculated at 80.04 kJ/mol, the activation enthalpy (ΔH) at 79.06 kJ/mol and the activation entropy (ΔS) at -0.062 kJ/mol.K. The Gibbs free energy (ΔG) was 100.59, 100.9 and 101.21 kJ/mol for 75, 80 and 85 °C respectively; these positive values indicated that the degradation of vitamin C was non-spontaneous. At the end of the process, it is concluded that temperature significantly affects (p < 0.05) the constant k for vitamin C in the thermal treatment of diluted persimmon pulp.
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Keywords
Vitamina C, Deterioro, Cinética, Propiedades termodinámicas, Espontaneidad