Fluidized Bed Granulation of Food Powder Using Superheated Steam Containing Water Micro-Droplets as Binder

Abstract

Fluidized bed granulation is widely applied to improve the flowability, dispersibility, and solubility of a variety of powdered food products. In fluidized bed granulation processing of powdered food, water or an aqueous polysaccharide solution is usually sprayed as binder on the powder for granule growth. However, the increased moisture content of granules can result in product spoilage and elongates the successive drying period. To reduce the amount of binder in the granulation process, fluidized bed granulation technology using superheated steam (SHS) containing water micro-droplets (WMD) as binder has been developed. Spraying of SHS accelerated the granule growth by condensing on the powder; however, coarse granules were produced when SHS alone was sprayed. Spraying with an optimal ratio of SHS and WMD produced granules of uniform size, with less binder moisture than conventional processes using polysaccharide solutions.