Cinéticas de secado y características de oleogeles de aceite de oliva y quitosano.
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Date
2024
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Abstract
En la actualidad, la sustitución de grasas saturadas perjudiciales para la salud por otras opciones más saludables es uno de los principales objetivos de la industria alimentaria. Una alternativa es utilizar aceites vegetales con buenas propiedades nutricionales estabilizados en forma de oleogel para el reemplazo de grasas saturadas y trans. En este trabajo se estudian oleogeles de aceite de oliva empleando como agentes estructurantes quitosano y vainillina. El aceite de oliva se atrapa en una red tridimensional construida mediante una base de Schiff formada entre los grupos funcionales del quitosano y de la vainillina, aplicando un método indirecto (emulsion-template). Se generaron dos tipos de emulsiones con distintas concentraciones de quitosano (0,7 y 0,8% en peso) manteniendo la relación vainillina/quitosano constante (4/3) y una relación másica de fase dispersa (aceite)/fase continua (agua) de 50:50 en peso, que fueron deshidratadas mediante secado convectivo a cuatro temperaturas (50, 60, 70 y 80°C)
Los resultados experimentales obtenidos permitieron determinar las cinéticas de secado de las emulsiones a distintas temperaturas, y su posterior modelización, a través de modelos empíricos y difusionales. Se analizaron las propiedades de textura del producto (dureza, adhesividad, cohesividad, elasticidad), y de calidad (retención de aceite, color y oxidación). Las condiciones óptimas del proceso de secado correspondieron a una temperatura de 70°C, ya que a temperaturas de aire superiores no se aceleró la cinética de secado. Se concluyó que el tiempo de secado y la concentración del gelificante son fundamentales para los parámetros de calidad y textura. La dureza aumentó con la concentración de gelificante y disminuyó con la temperatura, mientras que las demás propiedades lo hacen a la inversa. La retención de aceite es significativamente mejor a medida que aumenta la concentración de quitosano. Por otro lado, se obtuvieron altos valores de oxidación debido a la presencia de aldehídos en el sistema, provenientes de la vainillina, los que interfieren en las metodologías adoptadas.
En futuros trabajos se recomienda buscar alguna otra metodología para poder determinar la oxidación en el sistema. Asimismo, se recomiendo llevar a cabo un análisis reológico de los oleogeles para relacionar ese comportamiento con las propiedades analizadas en el presente trabajo, además de un análisis de estabilidad para comprobar que el oleogel producido sea viable en el tiempo.
The replacement of unhealthy saturated fats with healthier options is currently one of the main objectives of the food industry. One alternative is to use vegetable oils with good nutritional properties stabilized in the form of oleogels for the replacement of saturated and trans fats. In this work, olive oil oleogels are studied using chitosan and vanillin as structuring agents. Olive oil is trapped in a three-dimensional network built by means of a Schiff base formed between the functional groups of chitosan and vanillin, applying an indirect method (emulsion-template). Two types of emulsions were generated with different concentrations of chitosan (0.7 and 0.8% by weight) maintaining a constant vanillin/chitosan ratio (4/3) and a dispersed phase (oil)/continuous phase (water) mass ratio of 50:50 by weight, which were dehydrated byconvective drying at four temperatures (50, 60, 70 and 80°C). The experimental results obtained made it possible to determine the drying kinetics of the emulsions at different temperatures, and their subsequent modeling, through empirical and diffusional models. Product texture properties (hardness, adhesiveness, cohesiveness, springiness) and quality properties (oil retention, color and oxidation) were analyzed. The optimum conditions of the drying process corresponded to a temperature of 70°C, since at higher air temperatures the drying kinetics were not accelerated. It was concluded that the drying time and the concentration of the gelling agent are fundamental for the quality and texture parameters. Hardness increased with gelling agent concentration and decreased with temperature, while the other properties do the reverse. Oil retention is significantly better as chitosan concentration increases. On the other hand, high oxidation values were obtained due to the presence of aldehydes in the system, coming from vanillin, which interfere with the adopted methodologies. In future works, it is recommended to look for some other methodology to determine the oxidation in the system. It is also recommended to carry out a rheological analysis of the oleogels to relate this behavior with the properties analyzed in this work, in addition to a stability analysis to verify that the oleogel produced is viable over time.
The replacement of unhealthy saturated fats with healthier options is currently one of the main objectives of the food industry. One alternative is to use vegetable oils with good nutritional properties stabilized in the form of oleogels for the replacement of saturated and trans fats. In this work, olive oil oleogels are studied using chitosan and vanillin as structuring agents. Olive oil is trapped in a three-dimensional network built by means of a Schiff base formed between the functional groups of chitosan and vanillin, applying an indirect method (emulsion-template). Two types of emulsions were generated with different concentrations of chitosan (0.7 and 0.8% by weight) maintaining a constant vanillin/chitosan ratio (4/3) and a dispersed phase (oil)/continuous phase (water) mass ratio of 50:50 by weight, which were dehydrated byconvective drying at four temperatures (50, 60, 70 and 80°C). The experimental results obtained made it possible to determine the drying kinetics of the emulsions at different temperatures, and their subsequent modeling, through empirical and diffusional models. Product texture properties (hardness, adhesiveness, cohesiveness, springiness) and quality properties (oil retention, color and oxidation) were analyzed. The optimum conditions of the drying process corresponded to a temperature of 70°C, since at higher air temperatures the drying kinetics were not accelerated. It was concluded that the drying time and the concentration of the gelling agent are fundamental for the quality and texture parameters. Hardness increased with gelling agent concentration and decreased with temperature, while the other properties do the reverse. Oil retention is significantly better as chitosan concentration increases. On the other hand, high oxidation values were obtained due to the presence of aldehydes in the system, coming from vanillin, which interfere with the adopted methodologies. In future works, it is recommended to look for some other methodology to determine the oxidation in the system. It is also recommended to carry out a rheological analysis of the oleogels to relate this behavior with the properties analyzed in this work, in addition to a stability analysis to verify that the oleogel produced is viable over time.
Description
Tesis para optar al título de Ingeniero/a Civil Químico/a
Keywords
Cinética química, Aceite de oliva