CH634469A5 - Method of upgrading tobacco - Google Patents

Description

The invention relates to a process for refining tobacco by breaking down nitrates, nitrites and other nitrogenous compounds contained in the tobacco.

Many tobacco products, such as Burley, contain nitrates and / or nitrites that can produce toxic nitrogen oxides when smoked. Fermentation processes are known in which these nitrogen salts are degraded enzymatically, but only to a very small extent and only as a side effect to other enzymatic reactions.

The object of the invention is to break down nitrates and nitrites to an acceptable residual content in order to reduce the proportion of nitrogen oxides in the smoke as much as possible. The breakdown of the nitrates and nitrites should take place as selectively as possible, that is to say as far as possible avoiding conversions of the tobacco components accompanying the nitrates and nitrites.

The invention is characterized in that nitrogen-containing and other water-soluble compounds are washed out of the tobacco to be refined with water, that the tobacco extract solution obtained in this way is isolated and with an activated microorganism culture which under nitrogen deficiency conditions or under oxygen deficiency conditions reduces its nitrogen requirement or its oxygen requirement through nitrate and nitrite degradation it can be inoculated that this microorganism culture is kept in its exponential growth phase for eight to twenty-four hours by an added nutrient solution while maintaining the deficiency conditions, until the degradation has taken place and that the action of microorganisms on the now low-nitrate tobacco extract solution is then stopped immediately and that the solution components still present in this tobacco extract solution are added to tobacco that has been washed out beforehand. Under these conditions, the microorganisms remain in their exponential growth phase as long as the required nitrogen or oxygen requirements can be met from the nitrates and nitrites.

When applied, the microorganisms used are forced to cover their nitrogen or oxygen requirements from the nitrates and nitrites to be broken down, as a result of which they are broken down.

In the event of nitrogen deficiency conditions, the microorganisms are forced to meet their nitrogen requirements from the nitrates and nitrites to be broken down. The nitrogen that is in the nitrate or nitrite is used by the microorganisms to build up the organic compounds necessary for their life. These are mainly amino acids and proteins that do not interfere with smoking, on the contrary, they can have a beneficial effect on the taste of smoke. In the event of oxygen deficiency conditions, the microorganisms are forced to cover their oxygen requirements from the nitrates and nitrites to be broken down, as a result of which they are reduced to the level of nitrogen or ammonia. The nitrogen can escape without damage and the nitrogen, in the form of ammonium salts, amino acids and amines, does not form nitrogen oxides when smoked.

The exponential growth of the microorganisms under nitrogen deficiency conditions can be brought about in an aerobic environment by using a nitrogen-poor nutrient solution. The exponential growth of the microorganisms under oxygen deficiency conditions can be brought about in an anaerobic environment by using a solution poor in oxygen sources accessible to the microorganisms.

Since the added microorganism culture is already activated, its microorganisms have a lead of a few hours over other unwanted microorganisms that are still in their latent phase. Such undesirable microorganisms cannot catch up with this advantage within the exposure time limited to a few hours to such an extent that they can have a noticeable effect. To this

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In this way it can be ensured that the effect sought with the invention is selective.

The obtained low-nitrate tobacco extract solution can be added to the washed tobacco from which the tobacco extract solution was obtained. However, this is not always practical in large-scale technology. The same result can be achieved if the low-nitrate tobacco extract solution obtained from a first batch of tobacco is added to a second batch of tobacco that has been washed beforehand. The batches of tobacco should contain the same amount and quality of tobacco as possible.

In the tobacco extract solution, the nitrates and nitrites to be broken down are more accessible to the microorganisms than in tobacco. This is particularly true for tobacco ribs, and therefore the invention is preferably applicable to isolated tobacco ribs. The nitrates and nitrites in the strips can be treated without washing them out beforehand in accordance with the inventive method. The active sludge obtained in the treatment of the tobacco extract solution is expediently used and the treatment can thus begin with a very intensive action. The corresponding procedure is characterized in that the action of the microorganisms on the tobacco extract solution is terminated by withdrawing the active sludge and that this active sludge is sprayed onto tobacco leaves or tobacco strips to be refined and by an added nutrient solution while maintaining the deficient conditions for eight to twenty-four hours in exponential growth phase is held until the degradation is complete and then the action of microorganisms on the tobacco leaves or tobacco strips is then immediately stopped.

If the active sludge is not required for further degradation, it is advisable to add tobacco to it and to inactivate it so that the components contained in the active sludge benefit the tobacco.

Unfermented, air-dried tobacco often has a nitrate content of around 50 g per kg dry weight. In extreme cases, amounts of nitrate up to 80 g per kg dry weight were measured. The desired residual content depends on the reuse of the tobacco. For tobacco varieties that make up a significant part of the ready-to-smoke tobacco mixture, the desired residual content is a maximum of 5 g of the anions nitrate and nitrite per kg dry weight; For tobacco varieties that make up only a small proportion of the ready-to-smoke mixtures, the desired residual content may be somewhat higher. In general, the desired residual content is in the range from 3 to 20%, preferably 5%, of the original content of the tobacco to be refined, based on the total weight of the anions nitrate and nitrite.

The action can be stopped by not maintaining the living conditions of the microorganisms, for example by sharply lowering the temperature, drying, or else removing the microorganisms, for example by filtering them off as active sludge, if the action takes place in a liquid medium.

The microorganisms used can be bacteria, for example those of the genus Aerobacter, Pseudomonas, Micrococcus or Echerichia, but they can also be fungi, for example those of the genus Rhodutorula or Candida.

The invention can also be used advantageously in connection with a pure culture of the Enterobacter ae-rogenes bacterium, preferably from the standard strain ATCC 13048. Pure cultures of this standard strain are available from the German Collection of Microorganisms, Göttingen, Grise-

Bachstrasse 8, under the DSM admission no. DSM 30053 available.

Properties of Enterobacter aerogenes.

Motile rods 0.3-1.5 µm;

s Gram - gas evolution at 37 ° C

Glycerin +

Inositol 4-

Andonitol +

io Voges-Proskauer +

Methyl red -

Phenylamine deaminase -

Urease -

Catalase +

15 ornithine decarboxylase +

Lysine decarboxylase +

Hydrolysis of aesculin + growth in the presence of KCN + 20 on malonate as the only one

Carbon source +

The microorganism culture is preferably used as a pure culture, the degree of purity having to be sufficient to avoid significant side effects.

The microorganism culture can be stored frozen in liquid nitrogen and is then thawed and reactivated for reuse. For ongoing needs, it can be kept in an active state in a biostat from which 30 servings are constantly being taken.

The invention will now be explained in more detail with the aid of a few exemplary embodiments.

35 Example 1

Refining tobacco leaves under oxygen deficiency conditions

1 kg of Maryland tobacco, in which the nitrates and nitrites are to be reduced, is stripped. That makes 250 g 40 ribs and 750 g strips.

The 250 g ribs are washed with 1250 ml of 70 ° C warm water. Nitrate and nitrite present in the fins are extracted together with other water-soluble components. The rib extract 45 solution obtained in this way is drawn off from the ribs, placed in a 2 liter Erlenmeyer flask which is closed with a porous stopper, cooled to 30 ° C., with 12.5 g of D-gluco- se added and inoculated with 10 ml of an activated pure culture of the bacterium Enterobacter aerogenes ATCC 13048.

The inoculated rib extract solution is incubated at 30 ° C. on a shaker for 16 hours until the anions nitrate and nitrite are broken down to a content of 0.1 g per 1.

ss The resulting low-nitrate rib extract solution is then immediately centrifuged, whereby the microorganisms settle, which are then removed as active sludge. The active sludge can be reused, discarded or sprayed inactivated onto Ta-60 bak to add its ingredients to the tobacco.

The centrifugate from the low-nitrate rib extract solution, which still contains the remaining tobacco components extracted from the ribs, is added to the pre-dried, washed-out ribs, which are then dried to a moisture content of 20%. The tobacco constituents previously released from the ribs with the nitrates and nitrites then get back into the ribs, so that

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the fins then again contain essentially their original components, with the exception of the degraded nitrogen compounds, which are reduced to 1/6 of the original content.

Example 2

As in Example 1, with the only difference that the centrifugate of the low-nitrate rib extract solution is not added back to the ribs from which the extract was obtained, but to other ribs which were treated in the same way.

Example 3 Refinement of tobacco leaves under oxygen deficiency conditions 1 kg of Maryland tobacco, in which the nitrates and nitrites are to be reduced, is stripped. That makes 250 g ribs and 750 g strips. The 250 g ribs are treated as indicated in Example 1. When the active sludge is removed, the microorganisms of the 150 ml active sludge obtained are still in their exponential growth phase and are kept in this phase by this active sludge immediately together with 30 g D-glucose, 12.9 g peptone, 9.6 g NaCl, 6.75 g KH2P04 and 35.25 g Na2HP04 • 2H20 in 1500 ml water. This gives a suspension of active microorganisms, which is then immediately sprayed in a uniform distribution onto the 750 g strips of 20% moisture content. The sprayed strips then have a moisture content of 50% and are stored for 24 hours at 30 ° C with the exclusion of air. The microorganisms in the strips break down nitrates and nitrites down to V20 of the original content. The strips, which are reduced in their nitrate and nitrite content, are then dried to 20% moisture content for further processing. This inactivates the microorganisms remaining on the strips. The strips can now be processed further.

Example 4 Refinement of tobacco leaves under oxygen deficiency conditions 250 g of Burley tobacco leaves are washed with 1250 ml of 70 ° C. warm water. The resulting tobacco extract solution is further treated like the rib extract solution according to Example 1, and the resulting low-nitrate tobacco extract solution is centrifuged off from the active sludge and added to the tobacco leaves.

Example 5 Refining tobacco stems under nitrogen deficiency conditions 1 kg of Maryland tobacco, in which the nitrates and nitrites are to be reduced, is stripped. That makes 250 g ribs and 750 g strips.

The 250 g ribs are washed with 1250 ml of 70 ° C warm water. Water-soluble nitrogen compounds present in the fins are dissolved out together with other water-soluble constituents. The rib extract solution thus obtained is drawn off from the ribs, placed in a 2 liter Erlenmeyer flask which is sealed with a porous stopper, cooled to 30 ° C., mixed with 12.5 g of D-glucose and with 10 ml of one activated pure culture of the bacterium Enterobacter aerogenes ATCC 13048 inoculated.

The inoculated rib extract solution is aerated at 30 ° C on a shaker under sterile conditions with an air throughput of 1300 ml / min ~ and thereby incubated for 16 hours until the anions nitrate and nitrite break down to a content of 0.1 g per 1 are. Other nitrogen compounds are also broken down.

The resulting low-nitrate rib extract solution is then immediately centrifuged, whereby the microorganisms settle, which are then removed as active sludge. The active sludge can continue to be used, can be discarded, and can be sprayed inactivated onto tobacco to add its ingredients to tobacco.

The centrifugate from the low-nitrate rib extract solution, which still contains the remaining tobacco components loosened from the ribs, is added to the pre-dried, washed-out ribs, which are then dried to a moisture content of 20%. The tobacco components previously released from the ribs with the nitrates and nitrites then return to the ribs, so that the ribs then essentially again contain their original components, except for the degraded nitrogen compounds, which are reduced to 1/6 of the original content.

Example 6

As in Example 5, with the only difference that the inoculated rib extract solution is incubated for as long as 20 hours until 50% of the nicotine originally contained in the rib extract solution has been broken down. The rib extract solution then contains at most traces of nitrate and nitrite, because the microorganisms used only start to break down nicotine when there is no longer any nitrite or nitrate available.

Example 7 Refining tobacco leaves under nitrogen deficiency conditions

1 kg of Maryland tobacco, in which the nitrates and nitrites are to be reduced, is stripped. That makes 250 g ribs and 750 g strips. The 250 g ribs are treated as indicated in Example 5. The 750 g strips are individually immersed in 1250 ml of 50 ° C. warm water for 20 seconds. This removes the water-soluble compounds present in the superficial areas of the strips. Since the nitrates and nitrites contained in the strips are mainly contained in the superficial areas, they largely get into the water. In the strip extract solution obtained in this way, which also contains other nitrogen compounds, the nitrogen compounds are degraded microbiologically until the anions nitrate and nitrite are broken down to a content of 0.1 g per liter.

The strip extract solution is then concentrated and the strips are added again by spraying. For this purpose, the strip extract solution is treated like the rib extract solution according to Example 5.

Example 8 Refinement of tobacco leaves under nitrogen deficiency conditions

250 g of Burley tobacco leaves are washed with 1250 ml of 50 ° C warm water. The resulting tobacco extract solution is further treated like the rib extract solution according to Example 5 and the low-nitrate tobacco extract solution finally obtained is centrifuged off from the active sludge and added to the tobacco leaves again.

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Claims (7)

634 469 PATENT CLAIMS 1. A process for refining tobacco by breaking down nitrates, nitrites and other nitrogenous compounds contained in the tobacco, characterized in that nitrogenous and other water-soluble compounds are washed out of the tobacco to be refined with water, that the tobacco extract solution obtained in this way is isolated and activated with an activated one Microorganism culture, which under nitrogen deficiency conditions or under oxygen deficiency conditions can cover their nitrogen requirement or their oxygen requirement through nitrate and nitrite degradation, is inoculated that this microorganism culture is kept in its exponential growth phase for eight to twenty-four hours by maintaining an added nutrient solution while maintaining the deficiency conditions, until the degradation takes place and that the action of microorganisms on the now low-nitrate tobacco extract solution is then immediately stopped and that the solution still present in this tobacco extract solution Components are added to tobacco that was previously washed out. 2. The method according to claim 1, characterized by the application to isolated tobacco ribs. 3. The method according to claim 1 or 2, characterized in that the action of the microorganisms on the tobacco extract solution is stopped by withdrawing the active sludge and that this active sludge is sprayed onto tobacco leaves or tobacco strips to be refined and by an added nutrient solution while maintaining the deficiency conditions, eight to twenty-four Hours in exponential growth phase until the degradation is complete and then the action of microorganisms on the tobacco leaves or tobacco strips is then immediately stopped. 4. The method according spoke 1 or 2, characterized in that the action of the microorganisms on the tobacco extract solution is terminated by withdrawing the active sludge and that the removed active sludge is added to tobacco and inactivated. 5. The method according to any one of the preceding claims, characterized in that exponential growth of the microorganisms is brought about under nitrogen deficiency conditions in an aerobic environment by using a low-nitrogen nutrient solution. 6. The method according to any one of claims 1 to 4, characterized in that exponential growth of the microorganisms is brought about under oxygen deficiency conditions in an anaerobic environment by using a nutrient solution poor in oxygen sources accessible to the microorganisms. 7. The method according to any one of the preceding claims, characterized in that a pure culture of the bacterium Enterobacter aerogenes from the strain ATCC 13 048 is used