| 摘要 |
1,265,206. Evaporators, film type; treatment of coffee extract. PROCTER & GAMBLE CO. 18 July, 1969 [19 July, 1968], No. 36272/ 69. Heading BIB. [Also in Division A2] Volatile flavours are removed from aqueous coffee extract by forming the extract into a film in an evaporation zone maintained at an absolute pressure of 6-15" Hg, supplying heat to the film to maintain it at boiling point, maintaining the film in the zone for 5-30 seconds to evaporate therefrom volatile flavours and 5-30% by weight of its water content and recovering the evaporated flavour laden water fraction. In a process of making coffee powder, roasted ground coffee is steam distilled to give a flavour-laden distillate and then extracted to give an extract containing 10-40% by weight coffee solids. The extract is then subjected to the above mentioned flavour stripping process to form an aqueous coffee concentrate and an evaporated flavourladen water fraction which is condensed: The aqueous coffee concentrate is subjected to a film evaporation process comprising one or more evaporating steps, to remove 40-90% by weight water therefrom. In the latter evaporating step(s) the absolute pressure is maintained at 0.5-15" Hg and the temperature is 60-180‹F. The resultant concentrated extract is mixed with the flavour-laden distillate and the flavour-laden water fraction and the mixture is dried e.g. by spray-drying, freeze-drying or foam drying. The coffee powder may be subjected to the processes described in U.K. Specification No. 1,165,656 and Specification 1,265,205. The film evaporators may be falling film or rising-falling film evaporators in which the extract is moved through evaporating tubes mounted in a shell through which heat exchange fluid is passed. |
