Influence of drying air temperature and carrier agent concentration on the physicochemical properties of acai juice powder

The objective of this work was to study the influence of inlet air temperature and maltodextrin concentration on the physicochemical properties of acai juice powder produced by spray drying. The process was carried out in a mini spray dryer and the maltodextrin 10DE was used as carrier agent. Inlet air temperature varied from 138 to 202 degrees C and maltodextrin concentration varied from 10 to 30%. The characteristics analyzed were: moisture content, hygroscopicity anthocyanin retention, color, particle size distribution, and morphology. The increase in the temperature resulted in particles with larger size, less moisture content, more hygroscopy and with lower anthocyanin retention, besides promoting a reduction in the color parameter L* and in the hue angle H*. The increase of maltodextrin concentration resulted in less hygroscopy, particles with larger size, , with higher luminosity (L*), lower C* values and higher H* values. With respect to morphology, the increase in the temperature led to the formation of a great number of particles with smooth surface, which is due to the higher heat transfer and, consequently, to the faster formation of a membrane around the atomized drop.