Spray bulk density

Spray Drying and Agglomeration. Most instant coffee products are spray-dried. Stainless steel towers with a concurrent flow of hot ak and atomized extract droplets are utilized for this purpose. Atomization, through pressure nozzles, is controUed based on selection of the nozzles, properties of the extract, pressures used, bulk density, and capacity requkements. Low inlet ak temperatures (200—280°C) are preferred for best flavor quaHty. The spray towers must be provided with adequate dust coUection systems such as cyclones or bag filters. The dried particles are coUected from the conical bottom of the spray drier through a rotary valve and conveyed to bulk storage bins or packaging lines. Processors may screen the dry product to... 

The physical properties of spray-dried materials are subject to considerable variation, depending on the direction of flow of the inlet gas and its temperature, the degree and uniformity of atomization, the solids content of the feed, the temperature of the feed, and the degree of aeration of the feed. The properties of the product usually of greatest interest are (1) particle size, (2) bulk density, and (3) dustiness. The particle size is a function of atomizer-operating conditions and also of the solids content, liquid viscosity, liquid density, and feed rate. In general, particle size increases with solids content, viscosity, density, and feed rate. 

Table 7.7 Particle Size and Bulk Density Characteristics of Some Spray-Dried Ceramic Pressing Powders...

Instantized milk powder normally exhibits low bulk density but higher water dispersibility than conventionally spray-dried powder. However, the extra heat exposure from the agglomeration and redrying treatments causes additional Maillard reaction, whey protein denaturation, and related chemical and physicochemical reactions that tend to lower product quality. 

ASOs are synthesized as complex mixtures of diastereomers. In the solid state, they are amorphous, electrostatic, hygroscopic solids with low-bulk densities, possessing very high surface areas, and poorly defined or no melting points. Their good chemical stability allows them to be stored as lyophilized or spray-dried powders, or as concentrated, sterile solutions. For example, the 21-mer ASO Vitrave-ne (fomivirsen sodium intravitreal injectable) is approved in the USA for a storage condition from 2 to 25 °C [2]. 

Spray-dried lactose, starch, Diluent or Bulk density, tapped density,... 

Spray dried products, in general, are expected to meet a number of requirements. Properties of interest include size and size distributions, bulk density, moisture content, friability, appearance, reactivity and, with food products, aroma and flavour. Control of these properties requires close attention to all four unit processes described in Section 1.1. 

MacCarthy, D.A. 1985. Effect of temperature and bulk density on thermal conductivity of spray-dried whole milk powder. J. Food Eng. 4, 249-263. 

The heat cycle is followed by the cooling cycle. Because EPS is an excellent thermal insulator, it takes a relatively long time to remove the heat before demolding. If the heat was to remain, the product would distort. Cooling is usually by water spray over the mold. To facilitate removal, particularly for complex shapes mold release agents are used. The final density is about 0.7 to 10 lb/ft3 (II to 160 kg/m3) or in normal molding the density of the product will closely approximate the bulk density of the unheated beads. 

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