Desarrollo de un método analítico óptimo para determinar ácido galacturónico como indicador de pectina en pulpas de fruta
Fecha
2023
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Universidad de Guayaquil. Facultad de Ciencias Químicas
Resumen
El alcance del presente estudio reside en el desarrollo de un método instrumental que abarque las condiciones analíticas óptimas para la determinación de ácido galacturónico como indicador del análisis de pectina en muestras de pulpa de frutas, siendo más específico para pulpa de cacao. Para ello, se llevó a cabo la selección de dos tipos de matrices, entre ellas el mesocarpio de manzana y, el mucílago de cacao considerado este último como residuo del proceso agroindustrial de la especie Theobroma cacao. Los tipos de muestras fueron seleccionados con el objetivo de demostrar el funcionamiento del método en matrices de diferentes texturas, propiedades y composición. Para la evaluación de la metodología desarrollada se estudiaron variables como cantidad de muestra, temperatura de extracción y reacción, tiempo de medición, mediante diversos ensayos que proporcionaron resultados satisfactorios (precisión < 1% y exactitud 104.89%) para la determinación de ácido galacturónico en mucílago de cacao, a partir del tratamiento directo de muestra (1 g) frente a tetraborato de sodio en ácido sulfúrico concentrado, a 80 °C durante 10 minutos, y medición del producto coloreado (5-formil-2-furancarboxílico) frente al m- hidroxidifenil (compuesto cromóforo) a 520 nm. Los resultados de concentración de ácido galacturónico en las muestras analizadas reportaron valores de 62.72% en pectina extraída de mucilago, 68.31% en mucílago fresco, mientras que se obtuvo 36.56% en pulpa fresca de manzana, y 38.48% en pectina extraída de la pulpa de manzana. Este estudio permite concluir con el desarrollo de un procedimiento rápido, reproducible y efectivo para la identificación de pectina en base al contenido de ácido galacturónico en muestras frescas o procesadas de pulpa de manzana y de cacao.
The scope of this study relies on the development of an instrumental method that includes the optimal analytical conditions for the determination of galacturonic acid as an indicator of pectin analysis in fruit pulp samples, being more specific for cocoa pulp. For this purpose, the selection of two types of matrices was carried out, among them the apple mesocarp and the cocoa mucilage, the latter considered as a residue of the agroindustrial process of the species Theobroma cacao. The types of samples were selected with the objective of demonstrate the operation of the method in matrices of different textures, properties and composition. For the evaluation of the developed methodology, variables such as sample quantity, extraction and reaction temperature, measurement time, were studied through various tests that provided satisfactory results (precision < 1% and accuracy 104.89%) for the determination of galacturonic acid in mucilage. cocoa, from the direct treatment of the sample (1 g) against sodium tetraborate in concentrated sulfuric acid, at 80 °C for 10 minutes, and measurement of the colored product (5-formyl-2-furancarboxylic) against m-hydroxydiphenyl (chromophore compound) at 520 nm. The results of galacturonic acid concentration in the analyzed samples reported values of 62.72% in pectin extracted from mucilage, 68.31% in fresh mucilage, while 36.56% was obtained in fresh apple pulp, and 38.48% in pectin extracted from apple pulp. This study led conclude with the development of a fast, reproducible and effective procedure for the identification of pectin based on the galacturonic acid content in fresh or processed samples of apple and cocoa pulp.
The scope of this study relies on the development of an instrumental method that includes the optimal analytical conditions for the determination of galacturonic acid as an indicator of pectin analysis in fruit pulp samples, being more specific for cocoa pulp. For this purpose, the selection of two types of matrices was carried out, among them the apple mesocarp and the cocoa mucilage, the latter considered as a residue of the agroindustrial process of the species Theobroma cacao. The types of samples were selected with the objective of demonstrate the operation of the method in matrices of different textures, properties and composition. For the evaluation of the developed methodology, variables such as sample quantity, extraction and reaction temperature, measurement time, were studied through various tests that provided satisfactory results (precision < 1% and accuracy 104.89%) for the determination of galacturonic acid in mucilage. cocoa, from the direct treatment of the sample (1 g) against sodium tetraborate in concentrated sulfuric acid, at 80 °C for 10 minutes, and measurement of the colored product (5-formyl-2-furancarboxylic) against m-hydroxydiphenyl (chromophore compound) at 520 nm. The results of galacturonic acid concentration in the analyzed samples reported values of 62.72% in pectin extracted from mucilage, 68.31% in fresh mucilage, while 36.56% was obtained in fresh apple pulp, and 38.48% in pectin extracted from apple pulp. This study led conclude with the development of a fast, reproducible and effective procedure for the identification of pectin based on the galacturonic acid content in fresh or processed samples of apple and cocoa pulp.
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ÁCIDO GALACTURÓNICO, PECTINA, MUCÍLAGO DE CACAO, MALUS DOMESTICA GALA (MANZANA)