Nanoparticles of carotenoids by supercritical antisolvent of an emulsion

FACUNDO MATTEA; ÁNGEL MARTÍN; MARÍA JOSÉ COCERO

Valle Hermoso

Workshop; I Reunión Interdisciplinaria de Tecnología y Procesos Químicos; 2008

Carotenoids are natural pigments responsible for the red, orange and yellow color of many vegetables and other aliments. Some of the most abundant carotenoids are ß-carotene, lycopene, lutein and zeaxanthin. Because of the growing concern on replacing synthetic colorants in the food and pharmaceutical industry new technologies have been proposed to obtain better carotenoid colorant products. One of the main drawbacks of carotenoid substances is their low solubility in aqueous solutions. In order to extend the use of carotenoids in water based products the dissolution rate of these compounds in water could be enhanced by two different approaches, lowering the particle size and thus increasing the superficial area of the carotenoids, or coating the carotenoid particles with a hydrophilic polymer. Supercritical fluids are completely suitable for the processing of such labile compounds as carotenes. The use of mild temperatures, and the possibility of carrying out the whole process in an inert atmosphere are great incentives together with the high and fast super saturations that can be achieved in supercritical fluid methods. However with usual methods like supercritical antisolvent and gas antisolvent, only particles with sizes above 1μm have been produced. In this work a combination of two known technologies is proposed to obtain a better control in the particle size of carotene based colorants. The process consists in the use of nano-emulsions containing in its dispersed phase the substance going to be precipitated, and the use of supercritical fluids to produce the precipitation inside the droplets. With this method, the particle size is determined by the original droplet size in the emulsion, and it is possible to take advantage of the excellent properties of the supercritical fluids like their low diffusivity, and high solubility in the organic solvents employed to solubilize carotenes. However, some conditiions must be achieved in order to ensure the factibility of the process. The emulsion must remain stable in the pressence of the supercritical fluid, and the final product must be completley free of the organic solvent. A combination of emulsion technology and supercritical antisolvent has been used in this work, different surfactants where tested for the preparation of the nano-emulsion and a emulsion with droplet sizes below 1μ was obtained. Supercritical CO2 was used as antisolvent and the particle size obtained was compared with the original droplet sizes. Also the organic solvent content was measured to ensure the factibility of the process.