ENHANCING FLOWABILITY AND REHYDRATION OF HETERO-AGGREGATES BY BINDER-FREE FLUIDIZED BED AGGLOMERATION

Good rehydration and flowability are desirable properties of powdered ingredients in food formulations. Binder-free fluidized bed agglomeration involves spraying a liquid onto a bed of solid particles fluidized by hot air, where the liquid droplets collide with the moving particles, creating sticky zones on their surfaces by local wetting. Spraying water in the fluidized bed facilitates the transition of solids from the glassy to the rubbery state, thus enhancing agglomeration. When two or more particulate materials are processed simultaneously, effective mixing results in the formation of hetero-aggregates. In the present study, two types of maltodextrins, widely used as carriers and bulking agents in food powders, were combined to investigate the influence of fluidization gas temperature and water spray rate on agglomeration and mixing behaviour. Three mass ratios of maltodextrin DE6 and DE19 (1:1, 1:2, and 2:1) were examined, each optimized through seven experimental trials. Particle size, composition, moisture content, shape, fractal dimension, porosity, flowability, and rehydration were evaluated. The process successfully produced hetero-aggregates under optimal conditions, ensuring larger particles with target composition and low moisture content. The produced material had elongated and irregular shapes with edges and concavities. Agglomerates were classified as free-flowing powders, capable of faster and more homogeneous dispersion compared to the raw materials. Notably, the system with 1:1 mass ratio achieved instantaneous dissolution, less than 30 s against 15 min for the raw materials. Binder-free agglomeration can tailor particle properties for rapid solubilization and easy handling, underscoring its potential for practical applications in instant food systems and formulations requiring fast reconstitution.