Encapsulation of polyketide colorants in chitosan and maltodextrin microparticles

Abstract

This study aimed to encapsulate Talaromyces amestolkiae colorants in maltodextrin and chitosan microparticles using the spraydrying technique and to evaluate the biopolymers' capacities to protect the fungal colorant against temperature (65 °C) and extreme pH (2.0 and 13.0). The compact microparticles exhibited smooth or indented surfaces with internal diameters ranging between 2.58–4.69 μm and ζ ~ −26 mV. The encapsulation efficiencies were 86 % and 56 % for chitosan and maltodextrin microparticles, respectively. The shifted endothermic peaks of the free colorants indicated their physical stabilization into microparticles. The encapsulated colorants retained most of their absorbance (compared to the 0 h) even after 25 days at 65 °C. Contrary, the free colorant presented almost no absorbance after 1 day under the same conditions. Colorants in chitosan and maltodextrin matrices also partially maintained their colorimetric and fluorometric properties at acidic pH. However, only maltodextrin improved the resistance of the red colorant to alkaline environments. For the first time, the potential of polysaccharide-based microparticles to preserve polyketide colorants was demonstrated using 3D fluorescence. Therefore, this study demonstrated an alternative in developing functional products with natural color additives.