GB1269959A - Method for treating tobacco - Google Patents

Abstract

1,269,959. Treating tobacco. TANAG BASEL A.G. 13 May, 1969 [13 May, 1968], No. 24296/69. Heading A2C. Tobacco is mellowed and nicotine removed by a process that comprises passing through the tobacco a gaseous treatment medium containing water vapour, and controlling the process as a function of the alkalinity of the treatment medium leaving the tobacco. The process may be carried out at temperatures that are varied between 60 and 100‹C by variation of the degree of vacuum maintained in a container for the tobacco being treated, and ammonia gas may be added to the water vapour during part of the treatment. In an example, saturated water vapour at 60‹C is passed through the tobacco for about 5 min. after which an initial measure of condensate alkalinity is obtained by determining the pH value of a sample and by titration of a sample with sulphuric acid. Ammonia gas is then added to the water vapour until the condensate has a pH value of about 11, and the temperature is subsequently raised in stages, during which the introduction of ammonia is controlled to maintain a predetermined alkalinity of the treatment medium until, after a period at 80‹C, the introduction of ammonia is terminated and the water vapour temperature increased to 85‹C to expel the remaining ammonia, the alkalinity of the condensate being monitored at 5 min intervals so that treatment may be terminated when the condensate has a pH value of e.g. 0.2 less than its initial value. In another example, water vapour is cyclically varied in temperature between 60 and 100‹C until the alkalinity of the condensate, which is continuously monitored, has a desired final value. A modification of this example involves the introduction of ammonia during the low temperature parts only of each cycle.