| 摘要 |
A process for expanding tobacco is provided which employs liquid carbon dioxide as the expansion agent. Tobacco is contacted with liquid carbon dioxide to thoroughly impregnate the tobacco with the liquid carbon dioxide. The carbon dioxide impregnated tobacco is maintained at a temperature no lower than -2 DEG C. and under conditions of temperature and elevated pressure such that all or substantially all of the carbon dioxide which is in contact with the tobacco is in liquid form. After the impregnation has been completed, any excess liquid carbon dioxide which may be present with the tobacco may be removed from the tobacco. The elevated pressure is then reduced in order to convert the liquid carbon dioxide to solid carbon dioxide within the tobacco structure. The resulting solid carbon dioxide-containing tobacco is then subjected to conditions of temperature and pressure, preferably by rapid heating at atmospheric pressure, such that the solid carbon dioxide is vaporized and the tobacco is thereby expanded. Apparatus for carrying out the above described process is also provided. |
