Immobilization of natural betalain pigments in inorganic hosts

Abstract

In search of new food-grade pH sensitive formulations, red beet extract rich in betacyanin was included in different inorganic matrices based on silica and aluminosilicate to improve the stability of the dye. By the direct method of encapsulation of the pigments in silica support, stabilizing agents such as inclusion complex forming β-cyclodextrin and ascorbic acid were added. The post loading system assumes the synthesis of porous silica and aluminosilicate powders and the adsorption of the beet extract by these supports. The unloaded carriers were structurally and texturally characterized (X-ray diffraction, FTIR, N2-physisorption). The presence of betanin, approved as a red food colorant, was evidenced by UV–Vis spectroscopy in all the hosts. Color properties were investigated as well as the pH generated color variations of the powders exposed to ammonia in the head-space of a sealed vessel. The obtained results could widen the field of applications of beet extract, the prepared ecological formulations could provide added value to edible products packaging.

Keywords

• betanin
• encapsulation
• mesoporous silica
• aluminosilicate
• color parameters