Spray drying stages

Manufacturing Processing and Uses. In commercial production, aqueous urea solution is mixed with acetaldehyde in 1 1 molar ratios. An acid catalyst is introduced into the reaction mixture which is staged at various process temperatures. After neutralization with a base, the CDU is separated from the mother hquor by filtration or spray drying. 

After hardening, UF-resins consist of insoluble, more or less three-dimensional networks and cannot be melted or thermoformed again. At their application stage, UF-resins are still soluble or dispersed in water or are spray dried powders, which in most cases are redissolved and redispersed in water for application. 

In order then to determine what influences flavor retention during drying, one must focus attention on the very early stages of dehydration. In fact, it has been shown that the major fraction of total volatiles lost during nozzle-atomized spray drying occurs within ten centimeters of the pressure nozzle (17, 33, 35). 

The recovery of whole cells is best explained by the manufacturing procedure for baker s yeast. This process is almost identical to the early stage of protein recovery, except that the final product is the cell instead of the filtrate. After fermentation, the cells are spun out with a centrifuge, washed with water, and recentrifuged to yield a yeast cream with a solids concentration of approximately 18 percent. Cream yeast can be loaded directly into tanker trucks and delivered to customers equipped with an appropriate cream yeast handling system. Alternatively, the yeast cream can be pumped to a plate and frame filter press or an RDVF and dewatered to a cakelike consistency with 30-32 percent yeast solids content. The press cake yeast is crumbled into pieces and packed or spray-dried for dry products. After packaging, the yeast is ready for shipping to retail. 

Spray drying consists of four process stages ... 

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