Microencapsulation of Annatto Seed Extract: Stability and Application

Annatto is the most widely used natural colouring in the food industry, although with a certain degree of difficulty in its applicability due to its lower stability when compared to synthetic colorants. It has as its main component bixin, a substance responsible for its reddish-orange hue and water-insolubility, due to its nonpolar structure. In order to increase stability and the use of natural colorants as food ingredients, this study proposed to encapsulate the annatto seed extract, using maltodextrin and Arabic gum as encapsulating agents by the method of spray drying. The obtained powder was applied to distilled water in order to evaluate the stability, by colorimetry, of the colorant under the influence of light during the storage period. Tests for solubility, water activity and efficiency of microencapsulation were performed to characterize the encapsulated material. The choice of the technique and conditions of microencapsulation was found to be appropriate, given the obtained 75.69 % microencapsulation efficiency and 72 % solubility of the encapsulated material. During the stability test, the final product was subjected to cycles of light and darkness in a eighteen-day period, making it possible to ascertain the deleterious effect of light upon natural colorants, with an observable degradation of the red coloration, and greater bixin stability in the dark.