The objective of the investigation was to describe changes in the morphology and selected physical properties of protein hydrolysate powders with maltodextrin as a carrier. The powders investigated were obtained in a process of spray drying. Two inlet air temperatures (160 ºC and 200 ºC) and three raw material fluxes (0.9, 1.18, and 1.28 cm3/s) were used. The highest moisture content in powders (4.5 %) was obtained at a temperature of 160 ºC and with a 1.28 cm3/s flux of raw material. Decreasing the drying temperature and increasing the feeding flux of raw material resulted in the manufacturing of powders of a higher moisture value. The increased feeding flux of raw material and the drying temperature did not significantly impact the loose density value obtained. The values obtained ranged from 493 to 518 kg/m3. The drying temperature had a significant impact on the apparent density of particles and its increase caused the apparent density to increase. The drying temperature did not differentiate the density only when the raw material flux was the lowest. Changing the feeding flux of raw material did not show any statistically significant impact on the apparent density values obtained. The bed external porosity of powders ranged from 58 to 63 %. A statistically significant decrease in the bed external porosity was found only at a temperature of 200 ºC, and it occurred along with the increased raw material flux. The photographs taken by a scanning microscope demonstrated that the particles were characterized by a spherical, smooth-faced shape. The performed screen analysis of powders showed the increase in the particle size along with the increase in the feeing flux of raw material and in the drying temperature.
spray drying, maltodextrin, protein hydrolysate, density, porosity