| 摘要 |
The invention relates to the treatment of tobacco in order to cause its expansion by a process comprising the steps of subjecting it, in a treatment chamber to a reduced pressure, not greater than 7 kPa, impregnating the cell structure of the tobacco with isopentane vapours at a temperature ranging from 70 to 100 C and maintaining the tobacco in contact with the vapours at a pressure of at least 400 kPa, removing excess vapours of isopentane from the treatment chamber, contacting the impregnated tobacco with steam in order to expand the tobacco cell structure, reducing the pressure in the treatment chamber at a rate of at least 10 kPa/min, preferably 30 kPa/min, and then bringing the pressure in the treatment chamber back to the atmospheric pressure. The final filling value of the tobacco treated according to the claimed process is directly proportional to the rate at which the pressure in the treatment chamber is reduced following to the steam treatment of the tobacco.
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