Effect of carrier agents on the physical properties and morphology of spray-dried Monascus pigment powder

Spray drying is an economic technique used in preservation and production of Monascus pigment powder. This study was performed to encapsulate the Monascus pigment with maltodextrin using spray drying technique with three types of carrier agents: propylene glycol, mannitol and polyglycerol ester at different concentrations (0.5%, 1% and 1.5%). Analyses of particle size, the spattering behavior, microstructure, color value, and thermal profile were performed on the obtained powder. The addition of propanediol, mannitol and polyglycerol ester in combination with maltodextrin led to an increase of 17.5%, 45.8%, and 23.5% in the volume mean diameter of Monascus pigment powder, respectively. The decrease of spattering of Monascus pigment with maltodextrin was clearly evident in the case of formulations containing 1.5% polyglycerol ester. Scanning electronic microscopy analyses showed that Monascus pigment particle treated with maltodextrin exhibited microstructures that were smooth and dented, while the particles treated with carriers exhibited rough, irregular surface and adherence of smaller particles on their surfaces. UV-visible spectroscopy proved that the addition of carriers did not influence the molecular structure of Monascus pigment compared to the powder without carrier treatment. Differential scanning calorimeter analysis revealed that mannitol enhanced water vaporization during spray drying process as lower enthalpy change was observed in thermogram. The addition of an appropriate carrier (0.5%, 1.5% propanediol or 1% mannitol) improved the color values of Monascus pigment.