| 摘要 |
In a process for producing coffee agglomerates connected by bonds of melted coffee solids, soluble coffee powder is chilled to below 60 DEG F. and contacted with a moistening fluid to wet the surfaces of the particles, the wet particles are agglomerated and fused by heating to a temperature above their surface fusion point, and the agglomerates are cooled to below 80 DEG F. According to an example, spray dried soluble coffee powder having a particle size distribution of between 100 and 200 microns was ground to produce a particle size distribution of 95% between 2 and 50 microns. During the grinding the powder was chilled to a temperature of 15 DEG F. by admission of liquid carbon dioxide to the grinding chamber. The chilled and ground powder, which had a surface moisture content of between 5% and 15% and a total moisture content of between 3% and 6%, was fed through narrow slots in a vibrating distributor box as a series of parallel sheets to be agglomerated and diverted by jets of steam, two for each sheet, into a cylindrical drying chamber; each sheet was contacted with a first jet of steam (nozzle pressure 15 p.s.i.g.) at an angle of about 90 degrees and a second jet (nozzle pressure 8 p.s.i.g.) disposed at an angle of between 95 degrees and 135 degrees with respect to the direction of travel of the powder stream. In the drying chamber the moist agglomerates, having a total moisture content of about 5%-6%, were dried and fused at temperatures in the range 150 DEG -250 DEG F. by a flow of hot air. The warm agglomerates were then chilled by cold air (50 DEG F.) to prevent caking and sticking in storage.
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