Betaxantinas de Opuntia como colorante alimentario natural: caracterización, purificación y proyección tecnológica

[SPA] Debido a las crecientes restricciones en el uso de los colorantes alimentarios, la presente Tesis Doctoral se plantea respondiendo a la necesidad de las empresas de formular y diseñar colorantes alimentarios amarillos naturales de naturaleza hidrosoluble, y que además de aportar color, también posean demostradas propiedades como sustancias bioactivas beneficiosas para la salud. Como alternativa a los colorantes amarillos sintéticos se propone el empleo de un extracto colorante procedente de frutos de Opuntia ficus-indica. Definir el proceso de extracción de los pigmentos, caracterizar el extracto colorante, determinar la presencia de compuestos bioactivos, y conocer su comportamiento ante la acción de factores externos que pueden alterar su actividad deben ser las bases para un correcto diseño de este aditivo alimentario. El análisis de los resultados nos va a permitir conocer las características y propiedades del extracto colorante, y en base a esto vamos a elegir las matrices alimentarias más adecuadas sobre las que ser evaluado su comportamiento. Finalmente, los estudios de estabilidad en alimentos nos van a revelar la proyección tecnológica y viabilidad de este nuevo extracto colorante natural. Se selecciona una mezcla hidroalcoholica para la extracción de las betaxantinas presentes en los frutos de Opuntia. Tras un proceso de concentración a presión reducida se identifican ocho betaxantinas individuales y betanina entre las betacianinas presentes en el extracto. De todas, destaca como mayoritaria indicaxanteno (prolina-betaxantina). El análisis de carotenoides, flavonoides y fenoles totales confirma el potencial bioactivo del extracto colorante obtenido. El estudio de estabilidad al almacenamiento del extracto revela que tanto a 4 ºC como a 25ºC presenta tiempos de vida media similares a los de otros colorantes naturales comerciales. Con el fin de obtener el extracto en polvo se somete a un proceso de atomización y microencapsulacion con maltodextrinas con objeto de incrementar su vida útil, facilitar su comercialización y diversificar sus formatos disponibles. Se estudia su termosensibilidad a 30, 50, 70, y 90 ºC y se compara con la de otros colorantes amarillos naturales presentes en el mercado, como curcumina, β-caroteno, luteina, amarillo gardenia y riboflavina. Los resultados obtenidos confirman que la temperatura es uno de los factores que más afectan su estabilidad, pero a 30º C su comportamiento resulta optimo, por lo que su campo de aplicación esta en alimentos que no precisen elevadas temperaturas durante su preparación como es el caso de yogures, helados, zumos o bebidas refrescantes. Por último el extracto obtenido se incorpora en dos alimentos modelo (yogur y bebida refrescante) y se comprueba su excelente comportamiento durante un periodo prolongado de tiempo sin experimentar degradaciones en su color. [ENG] Due to increasing restrictions on the use of food colorants this Doctoral Thesis arises in response to the needs of the food industries to formulate and design water-soluble natural yellow food colorants. It is also important the bioactive and health-promoting properties of these substances. A new water-soluble colorant extract from Opuntia ficus-indica fruits is proposed as an alternative to synthetic yellow colorants. To establish the extraction process, to characterize the new colorant and to analyse its health-promoting characteristics are some objectives of this work. It is also important to know the effects of external factors in the potential of this colorant. The analysis of the results will allow us to know the main characteristics of this colorant, and then, the most appropriate foods will be chosen to assess its possibilities as new food colorant. Finally, the degradation studies in food model systems will reveal its technological approach and commercial viability. An water/EtOH (60:40, v/v) mixture was selected as extraction solvent to recover the betaxanthins from Opuntia fruits in a sequential extraction procedure. Pigment extract was chemically characterized and individual pigments were identified by HPLC, UV/VIS spectrometry and ESI mass spectroscopy. Proline-betaxanthin (indicaxanthin) was the predominant pigment, while all other betalains were present in comparatively low quantities. A concentrated pigment extract was obtained under rotary evaporation at low pressure. The Opuntia fruit extract was analyzed for determined bioactive constituents: flavonoids, total carotenoids and total phenolics. Pigment stability was checked at 4 º C and 25 º C. A powder extract was obtained by co-current spray drying. Maltodextrin was used as drying aid in order to increase its useful life, facilitate the commercialization and diversify its available formats. The thermosensibility of the Opuntia fruit extract was compared with the thermal stabilities of five natural yellow colorants used in foods —lutein, riboflavin, curcumin, s-carotene and gardenia yellow—over a temperature range 30-90 º C. Spectral properties and visual color were investigated during 6 hours of heat treatment. The results confirm that the temperature is one of the most important factors affecting its stability, but at 30 º C their behavior is optimal, so the Opuntia fruit colorant would be applicate in food that do not require high temperatures during its preparation as is the case of yogurt, ice creams, juices or soft drinks. This colorant was successfully applied in two food model systems: a yogurt and a soft-drink.[ENG] Due to increasing restrictions on the use of food colorants this Doctoral Thesis arises in response to the needs of the food industries to formulate and design water-soluble natural yellow food colorants. It is also important the bioactive and health-promoting properties of these substances. A new water-soluble colorant extract from Opuntia ficus-indica fruits is proposed as an alternative to synthetic yellow colorants. To establish the extraction process, to characterize the new colorant and to analyse its health-promoting characteristics are some objectives of this work. It is also important to know the effects of external factors in the potential of this colorant. The analysis of the results will allow us to know the main characteristics of this colorant, and then, the most appropriate foods will be chosen to assess its possibilities as new food colorant. Finally, the degradation studies in food model systems will reveal its technological approach and commercial viability. An water/EtOH (60:40, v/v) mixture was selected as extraction solvent to recover the betaxanthins from Opuntia fruits in a sequential extraction procedure. Pigment extract was chemically characterized and individual pigments were identified by HPLC, UV/VIS spectrometry and ESI mass spectroscopy. Proline-betaxanthin (indicaxanthin) was the predominant pigment, while all other betalains were present in comparatively low quantities. A concentrated pigment extract was obtained under rotary evaporation at low pressure. The Opuntia fruit extract was analyzed for determined bioactive constituents: flavonoids, total carotenoids and total phenolics. Pigment stability was checked at 4 º C and 25 º C. A powder extract was obtained by co-current spray drying. Maltodextrin was used as drying aid in order to increase its useful life, facilitate the commercialization and diversify its available formats. The thermosensibility of the Opuntia fruit extract was compared with the thermal stabilities of five natural yellow colorants used in foods —lutein, riboflavin, curcumin, s-carotene and gardenia yellow—over a temperature range 30-90 º C. Spectral properties and visual color were investigated during 6 hours of heat treatment. The results confirm that the temperature is one of the most important factors affecting its stability, but at 30 º C their behavior is optimal, so the Opuntia fruit colorant would be applicate in food that do not require high temperatures during its preparation as is the case of yogurt, ice creams, juices or soft drinks. This colorant was successfully applied in two food model systems: a yogurt and a soft-drink.Universidad Politécnica de CartagenaPrograma Oficial de Doctorado en Ingeniería Ambiental y de Procesos Químicos y Biotecnológico