ACACIA GUM AGGLOMERATION IN FLUIDIZED BED: INFLUENCE OF OPERATIONAL PARAMETERS ON PARTICLE GROWTH RATE AND PRODUCT QUALITY

Acacia gum is a food additive, that acts as an emulsifier and stabilizer, and can enrich the nutritional value of food. However, its spray dried particles present poor instant properties and dispersion in liquids and moderate flowability properties. These characteristics can be improved by fluidized bed agglomeration process. The aim of this work was to investigate the effects of the fluidizing air temperature (65 ºC and 85 ºC) and binder flow rate (1.5 mL / min and 3.0 mL / min) at system stability, at the granule growth kinetics, at process yield and at the product characteristics: final particle size and wettability. Acacia gum solution (20.0 % w / w) was used as binder. Particle size was monitored in-line in real time by the spatial filter velocimetry technique. Both the binder flow rate and fluidizing air temperature influenced the particle growth rate, it was also observed that the rapid increase in particle size impaired fluidization stability. The wetter conditions presented higher process yield and the better flow properties were obtained for the lower binder flow conditions. The wetting time of the material has been reduced from 600 s to less than 3 s for all operating conditions use.