Microencapsulation of betanins by spray drying with mixtures of sweet potato starch and maltodextrin as wall materials to prepare natural pigments delivery systems

Abstract

The potential use of Maltodextrin (MD) and Sweet Potato Starch (SPS) mixtures to encapsulate betacyanine from a beetroot extract by the spray drying (SD) process was studied. As the SPS content increased in the mixtures, the powder recovery, moisture content, hygroscopicity, porosity and solubility increased, whereas the values of wettability decreased. The encapsulated betacyanine content increased with the content of SPS in the mixtures, resulting in an increase in antioxidant activity. The reconstituted powders of MD/SPS mixtures in water showed non-Newtonian shear-thinning and a predominant viscous behaviour in the rheological tests, except for the sample with 100% SPS, which showed characteristics of a gel. The morphology of the microparticles was shown to depend on the SPS content with a tendency of the particles to aggregate FTIR analysis showed that the signals of specific groups of betanins were diminished, which is an evidence of the microencapsulation of the betanins, and this was corroborated by transmission electronic microscopy.