A second relatively new design for drying solid-particle foods incorporates the concept of the fluidized bed. In this system, the product pieces are suspended in the heated air throughout the time required for drying. As illustrated in Fig.12.8. The movement of product through the system is enhanced by the change in mass of individual particles as moisture is evaporated. The move of the product created by fluidized particles results in equal drying from all product surfaces. The primary limitation to the fluidized bed process is the size of particles that will allow efficient drying. As would be expected. Smaller particles can be maintained in suspension with lower air velocities and will dry more rapidly. Although these are desirable characteristics, not all products can be adapted to the process.