Enhanced physical and rheological properties of skim milk powder enriched with milk protein isolate via guar gum-assisted fluidized-bed agglomeration

Abstract

This study investigated the influence of fluidized-bed agglomeration using guar gum (GG) binder on the physical, thermal, and rheological properties of skim milk powder (SMP) mixed with milk protein isolate (MPI). Increasing the GG concentration (0-0.3%) generated larger particles and a more porous structure in the SMP-MPI mixture, leading to enhanced wettability and solubility, and decreased the Carr index and Hausner ratio values, suggesting improved powder flowability with reduced particle cohesiveness. After the agglomeration process using GG binder, color analysis revealed that the SMP-MPI powder became darker and more reddish-yellowish, while differential scanning calorimetry indicated a change in their thermal transition behavior. While all SMP-MPI mixtures exhibited pseudoplastic and thixotropic flow behavior, the agglomerated sample solutions exhibited higher apparent viscosity than the non-agglomerated mixture, which increased with an increase in GG concentration. In addition, increasing the GG concentration alleviated the temperature sensitivity of the SMP-MPI mixture viscosity.