Efecto de la adición de goma arábiga en la actividad antioxidante y antiinflamatoria de extractos de acerola y kiwi liofilizados

Abstract

[ES] Las frutas, especialmente las tropicales, presentan un gran interés en la nutrición humana por su elevado valor nutritivo y funcional, derivado de la presencia de vitaminas, minerales, fibra y otras sustancias bioactivas. El consumo regular de estas frutas está relacionado con la prevención y el tratamiento de diversas enfermedades. Sin embargo, por tratarse de productos perecederos, la llegada en condiciones óptimas a los países receptores está comprometida por el deterioro debido al transporte y al almacenamiento durante largos períodos de tiempo. La eliminación de agua mediante la técnica de liofilización es un medio para estabilizar el alimento sin provocar grandes pérdidas funcionales y de nutrientes. Para este trabajo se ha seleccionado como frutas de estudio la acerola y el kiwi. Ambas se caracterizan principalmente por su elevada actividad antioxidante debido a su contenido en vitaminas y compuestos fenólicos. Se estudiará el posible efecto sobre los principales compuestos fitoquímicos y sobre la actividad antioxidante del secado por liofilización y de la incorporación de goma arábiga como agente encapsulante y antihumectante. Se realizarán extracciones con distintos disolventes para obtener la mayor cantidad de compuestos bioactivos liposolubles (carotenoides) e hidrosolubles (vitamina C y compuestos fenólicos) y se evaluará la actividad antioxidante. Además se realizará un screening in vitro de la posible actividad antiinflamatoria de los extractos obtenidos de acerola y kiwi estudiando la inhibición de la producción de ácido nítrico en una línea celular de macrófagos de ratón.

[EN] Fruits, especially the tropical ones, are of great interest in human nutrition due to their high nutritional and functional benefits, which are provided by the presence of vitamins, minerals, fiber and other bioactive components. Moreover, it has been demostrated that regular consumption of these fruits is related to the prevention and treatment of various diseases. However, fruits are seasonal and perishable products and its quality is influenced by the deterioration suffered by transport and storage. Previous studies have shown that the removing of the water in fruits by freeze drying technique stabilizes the product without causing major alterations of their functional or nutritional benefits. In the present work, kiwi and acerola were selected to find out how important the influence of freeze drying could be in these products and also, if arabic gum could be used as an appropiated encapsulating agent. Therefore, our aim is to know the viabilitiy of the use of this technique to obtain neutraceutical products with high antioxidant properties. To reach this aim, extractions were performed with different solvents to obtain the larger amount of lipophilic bioactive compounds (carotenoids) and hydrophilic (phenolic compounds) and the antioxidant activity was evaluated by the use of three different methods: DPPH, FRAP and ABTS. Furthermore, a screening in vitro of the anti-inflammatory activity was performed by examining the inhibition of nitric acid in mouse macrophages. The results showed that acerola had higher amount of phytochemicals and greater antioxidant activity than kiwi. When comparing hydrophilic and lipophilic extracts, we found that both fruits showed higher antioxidant activity in the hydrophilic extract. Besides, the freeze drying affected differently the functional quality of both fruits, since the process improved the antioxidant activity of acerola, but decreased in kiwi. In relation with the encapsulation, in general, the incorporation of arabic gum improved both the stability of the phytochemicals studied and the antioxidant activity of the powders. Finally, the in vitro assays results show a single cell inhibition in the freeze dried kiwi extract which reachs 75%.