Fluidized-Bed Agglomeration of Milk Protein Isolate–Guar Gum Mixture Powders: Physical, Rheological, and Morphological Properties

This study examined the physical and rheological properties of agglomerated milk protein isolate (MPI)-guar gum (GG) mixtures with different lactose binder concentrations. Agglomerated mixtures (AMs) incorporating a lactose binder exhibited larger particles with irregular and porous structures compared to the non-agglomerated mixture (NAM), leading to an enhancement in powder flowability. Despite an increase in porosity, no significant difference occurred between the solubility of NAM and AM with distilled water (control) due to the formation of strong attractions among casein micelles. However, with an increase in binder concentration, the solubility of AMs was improved. In the NAM, GG aggregation occurred due to depletion interactions between MPI and GG, whereas little GG lumps were observed in the control (AM with 0% lactose binder) with a higher viscoelastic moduli value compared to NAM. However, with an increment in binder concentration, greater and larger aggregation occurred with a longer relaxation time due to relative dehydration. This rise in GG aggregation contributed to a decrease in viscoelastic properties. Collectively, our findings demonstrated that the agglomeration process with lactose binder the improved powder characteristics of MPI-GG mixtures and altered interaction patterns between the polymers. These findings may promote the application of agglomerated protein-gum mixtures in the food industry.