DRYING OF PARTICULATE FOODSTUFFS IN A CONFINED FLUIDIZED-BED

A novel drying apparatus, based on the confined fluidization technique , is presented. It consists of a fixed bed of coarse particles whose i nterparticle voids, filled with the fine powder to be dried, constitut e the fluidization environment. This system, particularly suitable for heat-sensitive products, can be considered as an alternative to fluid bed dryers with immersed heating surfaces. Drying experiments were pe rformed on two food powders, semolina and corn flour, and the effect o f different variables on the drying kinetics was investigated. The exp erimental results obtained show that confined fluidized bed dryers are very efficient units in which the drying time is reduced also with re spect to conventional fluid bed dryers. More work is needed to extend the application of this drying technique to food powders with high ini tial moisture content and small particle size.