EP0081231B1 - Process for the production of aromatic substances from a tobacco extract - Google Patents

Description

The invention relates to a method for obtaining aroma substances from a tobacco extract according to the patent claims. The new product is a clear tobacco aroma oil, free of polyphenols, resins and waxes, with a reduced (reduced) nicotine content of 5 to 50% relative (based on the tobacco from which the tobacco aroma oil is derived) and with that for Typical tobacco smell used in each case of starting tobacco. The process according to the invention effects the separation of clear tobacco aroma oil from tobacco extract.

The flavoring of tobacco plays a special role in the manufacture of tobacco products. Attempts to partially or wholly obtain the tobacco aroma oil typical of the respective tobacco from aroma-strong tobacco or tobacco waste in order to add it to other, low-aroma tobacco of the same provenance have so far failed because an absolute (clear) tobacco aroma oil free of resins and waxes with reduced nicotine content.

DE-A-2128779 describes a process for obtaining aroma substances and converting the aroma precursors from tobacco by extracting the tobacco with one or more solvents which are in the eluotropic range between trichlorethylene and ethyl acetate and from the extract obtained the aroma precursors are activated by a heat treatment between 110 and 180 ° C. The aroma products obtained by this process represent a wax-like, resinous mass which contains all waxes and resins as well as polyphenols and almost all nicotine of the starting product.

DE-A-2142 205 describes a method for the selective, aroma-preserving extraction of nicotine from tobacco in that in the first stage the aroma is extracted from the dry tobacco by treatment with dry, supercritical gases (e.g. CO2), which is then temporarily remains in the separating container B until the tobacco in the container A has been removed from the nicotine by means of moist CO ₂ by a second process stage, which is then separated out in the container D. In a third stage of the process, the flavorings in container B are mixed with e.g. B. supercritical C0 ₂ solved, returned to container A and deposited there on the tobacco.

This process is expensive in terms of tobacco aroma extraction and exploitation and is inefficient because the product obtained in the first stage is not a clear liquid tobacco aroma oil that can be separated from resins and waxes, but is a paste that contains almost all unwanted waxes and resins of the starting product and undesirable ones Includes polyphenols. In addition, these wax and resinous substances prevent the even distribution and aroma transfer when rearomatizing a tobacco to be loaded. One of the disadvantages of the polyphenols is that they impair the smoky taste.

DE-A-2 844 781 describes a process for the extractive treatment of plant and animal material, including the processing of tobacco using a two-component solvent, such as. B. 93 mole percent CO ₂ + 7 mole percent ethanol or 94 mole percent CO ₂ + 6 mole percent butane. The two-phase mixture is intended to ensure that, for. B. the adducts formed during organic solvent extraction and changes in the processed material can be avoided. Working with C0 ₂ under supercritical pressure conditions alone is required to achieve sufficient degrees of extraction - pressures of over 150 bar. According to the process of DE-A-2 844 781, these disadvantages are to be avoided if the CO ₂ used for the extraction has certain amounts, for. B. alcoholic solvents can be added as entrainer.

According to this process - just like according to the process of DE-A-2142 205 - only a paste-like substance containing little flavorings with all wax and resin contents as well as undesirable polyphenols of the tobacco used for the extraction is obtained as an intermediate product.

None of the known processes made it possible to achieve a tobacco extract or tobacco aroma. that has the typical tobacco smell for the starting tobacco used.

The object of the present invention is to provide a process for obtaining a clear, absolute tobacco aroma oil, which contains almost all the aroma substances of the starting product qualitatively and quantitatively, is free from resins, waxes and polyphenols and whose nicotine content - compared to the starting product - is greatly reduced .

This object is achieved by the method according to the patent claims.

Since according to the known methods of extraction of the tobacco with organic solvents or extraction of the tobacco with supercritical gases, such as. B. C0 ₂ , only a paste-like aroma product with almost all resins and waxes and polyphenols of the starting material was obtained, it is surprising that by a primary extraction with organic solvents or mixtures of these solvents with each other or with carbon dioxide and by a subsequent secondary extraction with C0 ₂ a two-phase resin / aroma oil mixture is obtained, which can easily be separated into a clear tobacco aroma oil and a solid resin / wax mixture without aroma carrier.

The invention is explained in detail below.

Tobacco in the sense of the present invention are fermented tobacco leaves, stems, stems or dust as well as tobacco waste.

For the purposes of the present invention, tobacco primary extract is one with customary organic solvents, in particular benzene, toluene, methanol, ethanol, n-propanol, methyl ethyl acetate, diethyl ether, acetone, n-propane, n-hexane, cyclohexane, petroleum ether, dichloromethane or trichloromethane, or extract prepared with mixtures of these solvents. A primary extract in the sense of the present invention is also a CO ₂ extract, ie extract produced with the help of C0 ₂ as a solvent.

Adsorbents for the purposes of the present invention are all common adsorbents, in particular activated carbon, aluminum oxide, magnesium oxide, sodium aluminum silicate, bleaching earth, bentonite, silica gel, diatomaceous earth, zeolitic molecular sieves etc.

Tobacco aroma oil in the sense of the present invention is a tobacco aromatic, oily liquid which is absolutely clear at normal temperature and free of resins and waxes, free of polyphenols, with a reduced nicotine content of 5 to 50% relative, (in particular 10 to 40% relative) on the tobacco from which the tobacco extract comes - which shows no clouding or precipitation when 95% by weight ethanol is added.

The preparation of the tobacco primary extract used according to the invention consists in particular in extracting the tobacco in one of the abovementioned solvents or (in the case of organic solvents) in a solvent mixture.

1 part by weight of pre-shredded tobacco is preferably extracted with about 3 to 30 parts by weight of one of the solvents mentioned (preferably CO ₂ , n-hexane or dichloromethane). Depending on the efficiency of the extraction devices present, the primary extraction is carried out for at least 10 minutes and at most 10 hours, preferably for 1 to 5 hours.

If organic solvents are used, the primary extraction takes place under normal pressure conditions. If CO _{2 is used} in the primary extraction, the pressure and temperature conditions in the extraction container and separating container, as well as the extraction time and CO ₂ flow rate, are identical to those which are specified below in connection with the (single-stage) secondary extraction.

The undissolved residue in the treatment with these solvents is separated off and the solvent-containing extract is evaporated down until a syrup-like, solvent-free tobacco extract is obtained. If organic solvents are used, the evaporation is preferably carried out under reduced pressure, particularly preferably at about 15 torr. In the case of the use of C0 ₂ , the evaporation takes place in the separating container, as already stated above, under the pressure and temperature conditions as specified below for the (single-stage) secondary extraction.

A tobacco primary extract obtained in this way contains u. a. Polyphenols, resins / waxes, nicotine and, as the inventor has determined, is in an easily accessible form which is particularly suitable for the subsequent secondary extraction (with CO2).

The tobacco primary extract obtained is then intensively mixed according to the invention with an adsorbent until there is a uniform distribution between the extract and the adsorbent. In this case, particularly preferred adsorbent _": sodium aluminum silicate, bentonite, magnesium oxide, or zeolitic molecular sieves The mixing ratio of extract. Adsorbent is variable and can vary depending on the consistency of the extract, the density and particle size of the adsorbent and the desired consistency of the mixed product can be adjusted. In general, a mixture ratio of extract: adsorbent between 1: 0.1 to 1:10 is sufficient; preference is given to a powdery extract mixture with a mixing ratio of extract: adsorbent of 1: 0.3 to 1: 6.

The extract / adsorbent mixture should not fall below the ratio 1: 0.1, because the adsorbent used according to the invention, the dissolving of the aroma substances in the subsequent secondary extraction with CO ₂ (in the extraction container) and the separation in the separation container as easily separable from resins and waxes, clear absolute tobacco aroma oil significantly influenced.

A mixing ratio of more than 1:10 also gives. a good detachment and separation of the tobacco aroma oil, although a larger pressure vessel volume has to be accepted.

The mixture of primary extract and adsorbent is treated according to the invention in a first pressure vessel (extraction vessel), preferably high-pressure vessel, with CO ₂ under certain pressure and temperature conditions until all the aroma substances in the second pressure vessel (separator vessel) downstream of the extraction vessel are considered to be slightly of resins and waxes separable, oily liquid.

This secondary extraction with CO ₂ according to the method of the invention is achieved by supercritically (> 73 bar and> 31.3 ° C) or in relation to the CO ₂ used for the extraction of the extract / adsorbent mixture with respect to pressure and temperature Pressure and temperature subcritical «73 bar and <31.3 ° C) or with regard to pressure supercritical (> 73 bar) and with regard to temperature subcritical (<31.3 ° C).

When working with supercritical pressure and temperature, pressures from 85 to 250 bar and temperatures from + 35 ° C to + 90 ° C are preferred. When working in the subcritical pressure and subcritical temperature range, pressures from 25 to 70 bar and temperatures from + 5 ° C to + 25 ° C are preferred. When working in supercritical printing and un In the critical temperature range, pressures from 85 to 200 bar and temperatures from + 10 ° C to + 30 ° C are preferred.

If a particularly low nicotine content in the end product (secondary extract) is desired (e.g. from 5 to 10% relative, based on the tobacco that was used for the primary extraction), an additional CO _z - can be used between the claimed primary extraction and the claimed secondary extraction. Extraction step at low temperatures are interposed. For this purpose, the extract obtained in the primary extraction and mixed with the adsorbent is treated in advance at CO _z extraction temperatures of ―25 ° C to + 5 ° C and CO ₂ extraction pressures of about 20 to 25 bar; In this intermediate CO ₂ extraction step, the expansion in the separating tank takes place under subcritical pressure and temperature conditions, with a separation (of nicotine) in the separating tank at temperatures of about + 15 ° C to + 30 ° C and at pressures of about 2 to 15 bar is preferred. An extraction time of 0.5 to 2 hours, preferably about 1 hour, and a CO ₂ flow rate of 5 to 50 kg / hour, preferably 10 to 30 kg / hour, are sufficient. Surprisingly ₂ extraction step are almost exclusively nicotine and other alkaloids in this intermediate C0 (but not other -soluble se CO _Z constituents, such as. For example, flavoring agents, resins, waxes, polyphenols etc.) removed from the Frimärextrakt / adsorbent mixture and excreted in the separation tank. The nicotine obtained is removed from the separation container before the subsequent secondary extraction (aroma extraction) begins with CO ₂ .

In the method according to the invention, in particular in the secondary extraction, the deposition conditions in the expansion tank (separation tank) are decisive for the quality and quantity of the product obtained according to the invention. The relaxation pressures and relaxation temperatures are expediently in the subcritical range of C0 ₂ (subcritical pressure / subcritical temperature). Pressures of 45 to 65 bar and temperatures of 15 to 30 ° C are preferred; pressures of about 50 to 55 bar and temperatures of 20 to 25 ° C. are particularly preferred. The separation in the expansion tank is preferably carried out with simultaneous pressure and temperature lowering than the pressure and temperature conditions prevailing in the extraction tank.

Also, the amount of the extraction vessel by flowing C0 ₂ and the duration of the flow are for the inventive Ver ^f AH rensweise significantly. Treatment times totaling 0.5 to 8 hours, preferably 1 to 5 hours, particularly preferably 2 to 4 hours are expedient; A total amount of CO _{2 is} expedient from 0.3 to 35 kg / hour, preferably 3 to 30 kg / hour, particularly preferably 5 to 15 kg / hour, based on 1 kg of untreated tobacco.

As already explained above, the conditions for CO ₂ extraction given above for the (single-stage) secondary extraction, such as pressure and temperature in the extraction container, pressure and temperature in the separation container, extraction time and CO ₂ flow rate also apply to the primary extraction, if at you use CO ₂ as a solvent. It is therefore not necessary to list these parameters again, especially in the case of primary extraction.

In the process according to the invention, after the secondary extraction has ended, a solid / oil mixture which is already present in two phases is obtained upon removal from the expansion tank. By simple filtration, this mixture can be separated into a clear, absolute tobacco aroma oil free of polyphenols with a greatly reduced nicotine content and a solid resin / wax mixture with a relatively high nicotine content.

A special characteristic of the tobacco aromatic oil obtained according to the invention is also that it has the tobacco smell typical of the starting tobacco used in each case. This characteristic clearly distinguishes it from all tobacco extracts known to date, because none of the conventional tobacco extracts made it possible to produce the typical smell of the respective starting tobacco. Based on this characteristic feature of the tobacco extract obtained according to the invention, it can be assumed that its material composition is completely new compared to the prior art.

The present invention is the first, starting from a product (tobacco primary extract). which contains flavors, polyphenols, nicotine, resins, waxes and other substances side by side, achieves a separation and recovery of the tobacco flavor as a clear and absolute oil, and this. with measures that are easy to carry out and a particularly efficient result.

No indication of the prior art could be found either for this process as such or for the product obtained. It is remarkable and surprising about the product obtained according to the invention that after the secondary extraction has ended, an easily separable, clear layer of tobacco aroma oil with a greatly reduced nicotine content, free of polyphenols, resins and waxes and a resinous wax-like layer can be removed, which is an essential one Proportion of nicotine in the primary extract.

It was surprising that the tobacco ingredients, which are obtained by primary extraction according to the procedure according to the invention, behave in a mixture with a powdery adsorbent and subsequent secondary extraction (with CO ₂ ) with respect to their viscosity, their solubility and separation ratios very different than the same ingredients that only the primary extraction (also the C0 ₂ 7 Primary extraction), e.g. B. from tobacco leaves.

This is also very clear in the case of the particularly efficient nicotine extraction which may be interposed according to the invention (if appropriate an interposed CO2 extraction step). According to the current teaching, nicotine and polyphenols are only used in the presence of moisture, for. B. extracted from tobacco leaves with the help of C02. In the procedure according to the invention, however, moisture is not added or used in any process step, and nevertheless almost all of the nicotine is dissolved from the primary extract prepared according to the invention and deposited in the separating container. This new finding also results in the inventive process variant (if desired) nearly pure nicotine selectively from the primary extract / adsorbent mixture by (dry) CO ₂ extraction at temperatures from - 25 ⁰ C to + 5 ° C to extract.

Another surprise is based on the productivity and the purity of the smell of the product produced according to the invention and on its smoke-improving effect. Little is known about the aromatic oil, especially tobacco. Aroma oils obtained in a conventional manner were only produced by steam distillation on a laboratory scale. The oils obtained were of numerous foreign smells, such as. B. chamomile, caraway, peppermint, valerian and amyl alcohol, which are probably caused by artifact formation. The yield of such tobacco oils was about 0.1 to 0.2%. As already stated above, the tobacco aroma oil obtained according to the invention, which has the typical and pure smell of the starting tobacco used in each case, is clearly different from this. So smells like B. the Havana tobacco flavored oil obtained from Havana tobacco, Kentucky tobacco flavored oil obtained from Kentucky tobacco. In a similar way, aromatic oils obtained from Virginia, Orient or Burley tobacco show the very typical and pure smell of the respective tobacco type. Because of this particular characteristic, which is clearly different from the prior art, it should be noted that the tobacco aromatic oil obtained according to the invention is completely new in its material composition compared to the products of the prior art.

The tobacco aromatic oil obtained in the manner according to the invention is free from foreign odors, free from polyphenols, resins and waxes, has a reduced nicotine content which is only 5 to 50% relative to the tobacco leaves used, and is obtained in yields of 0.8 to 2%. Get 5% (absolute oil).

With regard to the yield in the aromatization of tobacco, 50 ppm of the product obtained according to the invention already show z. B. from Havana tobacco the same yield and intensity in the aroma as about 250 ppm of an aroma product obtained by known methods of steam distillation from Havana tobacco.

The tobacco aroma oil obtained according to the invention can be used to aromatize tobacco or tobacco products, this aromatization being able to be carried out either directly by tobacco or by aromatizing porous carrier material or tobacco adhesive material.

In the case of direct exposure to tobacco, the tobacco aromatic oil obtained according to the invention is not only suitable for flavoring weak-flavored tobacco or reconstituted tobacco by means of sauces (“casing”), but is also particularly suitable as a “top flavor”.

Another type of flavoring is that the tobacco aromatic oil is applied to porous carrier materials which are in contact with tobacco or tobacco products. Such porous support materials can e.g. B. in the form of pieces of paper or clay, dummies. inner packaging material (e.g. boxes, bags, etc.).

A further embodiment of flavoring using the tobacco aromatic oil according to the invention is also the addition to adhesive material for tobacco products. Examples of these are adhesives as are commonly used for tobacco products, e.g. B. Adhesives for cigar wrappers, cigarette paper, etc.

The tobacco aroma oil obtained according to the invention can be used to decisively influence any fluctuations that occur during production (quality differences or other differences in the smoky taste) of the tobacco.

The amount of tobacco aromatic oil used to flavor tobacco or tobacco products can vary depending on the nature of the tobacco and the desired flavoring. In the case of z. B. Havana tobacco aroma oil obtained according to the invention is preferably used for loading 25 to 100, particularly preferably 40 to 60 mg of tobacco aroma oil per kg of tobacco, ie. H. 25 to 100 ppm, preferably 40 to 60 ppm.

The high productivity and intensity that can be achieved with the product obtained according to the invention is particularly promoted by the fact that a tobacco aromatic oil that is free of resin, polyphenol and wax is present. This particular quality of the tobacco aroma oil also represents a particularly characteristic and novel feature compared to the prior art.

A device which is particularly suitable for carrying out the secondary extraction according to the invention is described below (see attached drawing):

Liquid C0 ₂ is removed from the tank 1 in the subcritical pressure and temperature state. Through the heat exchanger 2, the C0 _{2 is set} to the desired subcritical or supercritical temperature and, with the aid of the high pressure pump 3, the desired supercritical or subcritical pressure. Through the flow meter 16, the CO ₂ enters the extraction container 4, where the extraction of the mixture of primary extract and adsorbent takes place. The extraction container 4 is filled and emptied with product discontinuously by opening and closing the head opening after each extraction. The pressure prevailing in the extraction container is determined with the pressure sensor 14. The liquid or fluid CO ₂ , which contains the dissolved tobacco constituents, is led via the throttle valve 6 to the pressure control valve 8 (= expansion valve) and introduced into the expansion tank 10 through the heat exchanger 9. The separation of the tobacco constituents dissolved in the CO ₂ is initiated by the pressure control valve 8 and supported by lowering the temperature in the heat exchanger 9. In the expansion tank 10, the extracted tobacco components separate into a clear tobacco aroma oil and a waxy, resinous nicotine product, which are either removed continuously through the valve 17 or after the extraction has ended by opening the tank 10. At the end of each extraction, opening the valve 5 also relieves the pressure of the extraction side of the device. The C0 ₂ emerging from the expansion tank 10 during the extraction is recirculated via line 11. The device can be controlled by hand or by means of the electrical control device 12, the inputs of which are the temperature measured with a temperature sensor 13 in the extraction container 4, the pressure measured with pressure sensors 14 and 15, and the CO _Z streams emerging from the pressure containers 4 and 10 as well as the flow rate measured with the flow meter 7. The pressure control valve 8 and also the cooling capacity in the heat exchanger 9 are set as a function of these measured values.

If CO _{2 is used} as the solvent in the primary extraction according to the claims, the device described and explained in the drawing can also be used here.

The following examples illustrate the invention without restricting its application.

The nicotine was determined spectrophotometrically in accordance with the method of H. Kuhn known from «Handbuch der Lebensmittelchemie Bd. VI, (1970), pages 321 to 325.

example 1

1,000 g of Havana tobacco (water content 6.5%, nicotine content 1.27%) are crushed in a knife mill and exhaustively extracted in 10 liters of dichloromethane and the solvent is evaporated off under a vacuum of 15 torr.

75 g of solvent-free, dark, syrup-like dichloromethane extract (primary extract) were obtained, which was mixed intensively with 90 g of Na aluminum silicate (Na-Al zeolite) in a kneading apparatus (mixing ratio 1: 1.2).

The mixture was treated with CO ₂ in a closed high-pressure extraction container at a pressure of 230 bar and a temperature of 65 ° C. for 120 minutes. The pressure on the relaxation side was 50 bar, the temperature 24 ° C.

The flow rate of C0 ₂ is 6 kg / hour.

After the end of the experiment, 40.1 g of a two-phase mixture were removed from the flash tank, which was separated by simple filtration into 22.5 g of clear, oily tobacco aroma oil and 17.6 g of a resin / wax precipitate.

The yield of clear, absolute tobacco aroma oil was 2.25% of the tobacco used. The nicotine content was 19.92%, which is 35% relative to the nicotine present in the tobacco.

The yield of the resin / wax deposit was 1.76%, the nicotine content 43% absolute, which is 60% relative to the nicotine present in the tobacco.

The tobacco aroma oil obtained was free from resins and waxes and showed no precipitation and no clouding when 95% by weight ethanol was added.

Example 2

1,000 g of Kentucky tobacco (water content 8.0%, nicotine content 1.7%) are crushed in a cutting mill and extracted in a CO ₂ high-pressure extraction system (according to the drawing) with C0 ₂ as solvent:

• Druck im Extraktionsbehälter : 250 bar
• Temperatur im Extraktionsbehälter : 40⁰ C
• Druck im Entspannungsbehälter : 55 bar
• Temperatur im Entspannungsbehälter : 22° C
• Dauer der Behandlung : 3 Stunden.
• Durchflußmenge CO₂: 8 kg/Stunde.

Extraction conditions:

• Pressure in the extraction container: 250 bar
• Temperature in the extraction container: 40 ⁰ C.
• Pressure in the expansion tank: 55 bar
• Temperature in the relaxation tank: 22 ° C
• Treatment duration: 3 hours.
• Flow rate CO ₂ : 8 kg / hour.

After the extraction is complete, 70 g of a brown, solid paste (primary extract) are removed from the flash tank and mixed intensively with 140 g of bentonite.

Analogously to the conditions mentioned in Example 1, this mixture is subjected to a secondary extraction with CO ₂ .

After the secondary extraction had ended, 38 g of a two-phase mixture were removed from the flash tank, which was separated by pressure filtration (filter pressure 5 bar) into 29 g of a resin / wax mixture and 9 g of clear tobacco aroma oil.

The tobacco aromatic oil obtained was free from resins, waxes and polyphenols and had the smell typical of Kentucky tobacco. No turbidity occurred when 95% by weight ethanol was added.

Example 3

1,000 g Burley tobacco (water content 7%, Niko tin content 2.85%), were ground in a knife mill, exhaustively extracted in 6 liters of n-hexane and the solvent used was completely evaporated at a vacuum of 20 torr.

65 g of solvent-free, dark, syrup-like primary extract were obtained, which was mixed intensively with 260 g of magnesium oxide (mixing ratio 1: 4).

The mixture was then subjected to an intermediate CO2 extraction step in a closed high-pressure extraction container and only then subjected to the secondary extraction:

1st stage :

• CO ₂ extraction temperature: ―17 ° C
• CO ₂ extraction pressure: 20 bar
• Temperature in the expansion tank: + 18 ° C
• Pressure in the relaxation tank: 8 bar Treatment time: 40 minutes

The flow rate of C0 ₂ is 25 kg / hour.

After the treatment time has expired, 25 g of an almost colorless and odorless oil are removed from the relaxation tank. The nicotine level of this oil was 94.1% absolute, which is 82.5% relative to the nicotine present in the tobacco.

2nd stage (secondary extraction):

• CO₂-Extraktionstemperatur: + 15⁰ C
• CO₂-Extraktionsdruck : 60 bar
• Temperatur im Entspannungsbehälter : + 20° C
• Druck im Entspannungsbehälter : 50 bar
• Behandlungsdauer der 2. Stufe : 200 Minuten

The same material that was still in the extraction container was further treated as follows by increasing the pressure and temperature:

• CO ₂ extraction temperature: + 15 ⁰ C.
• CO ₂ extraction pressure: 60 bar
• Temperature in the relaxation tank: + 20 ° C
• Pressure in the expansion tank: 50 bar
• Second stage treatment time: 200 minutes

The flow rate of CO ₂ was 15 kg / hour.

At the end of the treatment period, 29.7 g of a two-phase mixture were removed from the flash tank, which was separated into 15.5 g of clear tobacco aroma oil and 14.2 g of resin / wax precipitate by simple filtration.

The yield of clear tobacco aroma oil was 1.55% of the tobacco used, the nicotine content was 9.55% absolute, which is 5.2% relative to the nicotine present in the tobacco. The tobacco aroma oil obtained was free from resins and waxes and showed no precipitation and no clouding when 95% by weight ethanol was added.

Example 4

1,000 g of oriental tobacco (Izmir) (water content 7.2%, nicotine content 1.45%) were extracted exhaustively in 8 liters of petroleum ether and the solvent was evaporated off completely at a negative pressure of 15 torr.

58 g of solvent-free, dark, syrup-like primary extract were obtained, which was mixed intensively with 23.2 g of diatomaceous earth (mixing ratio 1: 0.4). The mixture was treated with CO ₂ in a closed high-pressure container for 180 minutes at a pressure of 180 bar and a temperature of + 20 ° C.

The pressure on the relaxation side was 50 bar, the temperature + 20 ° C. The flow rate of CO ₂ is 10 kg / hour.

After the end of the experiment, 20 g of a two-phase mixture were removed from the flash tank, which was separated into 12 g of clear, absolute tobacco aroma oil and 8 g of resin / wax precipitate by simple filtration.

The yield of clear tobacco aroma oil was 1.2% of the tobacco used, the nicotine content was 23.2% absolute, which is 19.17% relative to the nicotine present in the tobacco.

The resin / wax precipitate had a nicotine content of 57.2% absolute, which is 31.5% relative to the nicotine present in the tobacco.

The tobacco aroma oil obtained was free from resins and waxes and showed no precipitation and no clouding when 95% by weight ethanol was added.

Example 5

The yield of the tobacco aromatic oil obtained according to the invention was demonstrated as follows:

With the help of known methods of steam distillation, tobacco aroma oil was obtained from the same Havana tobacco - as used in Example 1 ―0.14% clear and in 95% by weight - ethanol which is not cloudy. The nicotine content of the aromatic oil was 0%.

• (Versuch A) 200 mg, in einem weiteren Versuch (Versuch B) 250 mg

dieses Aromaöls in einer ethanolischen Lösung auf je 1 kg zuvor entaromatisierten Tabak aufgesprüht. In einem weiteren Versuch

• (Versuch C) wurden 50 mg

des nach dem erfindungsgemäßen Beispiel 1 gewonnenen Tabak-Aromaöls in einer ethanolischen Lösung ebenfalls auf 1 kg zuvor entaromatisierten Tabak aufgesprüht.To assess the fertility were in an experiment

• (Experiment A) 200 mg, in another experiment (Experiment B) 250 mg

this aromatic oil is sprayed in an ethanolic solution onto 1 kg of previously dearomatized tobacco. In another attempt

• (Experiment C) became 50 mg

of the tobacco aroma oil obtained according to example 1 according to the invention is also sprayed onto 1 kg of tobacco which has previously been de-aromatized in an ethanolic solution.

The sensory comparison brought the following result:

The tobacco from trial A:

This stood out due to its low aroma intensity and was also not very expressive in terms of its overall aroma, even in the smoky taste.

The tobacco from experiment B:

It was a little more expressive in the aroma, accompanied by foreign smells, and a disadvantageous sharpness in the smoky taste was also found.

The tobacco from experiment C:

It had an intense, pure, rounded aroma with no foreign smell and was in the Rauchge taste full of heartiness. Tobacco C was clearly preferred and is best suited for flavoring.

Claims (12)

1. Process for the extraction of aromatic substances from a tobacco extract, known as primary extract, which is obtainable with a solvent, this solvent being selected from benzene, toluol, methanol, ethanol, n-propanol, methylethylace- tate, diethylether, acetone, propane, n-hexane, cyclohexane, petroleum ether, dichloromethane, trichloromethane or mixtures of these solvents or carbon dioxide, characterized in that the primary extract is mixed with an adsorbing agent, this mixture with C0₂ is subjected in a closed pressure tank, known as an extraction tank, to a secondary extraction, and in a second closed pressure tank, known as a separating tank, a clear tobacco aromatic oil with reduced nicotine content is extracted which is easily separated from resins and waxes.

2. Process according to one of the above claims, characterized in that magnesium oxide, activated charcoal, aluminium oxide, sodium aluminium silicate, fuller's earth, bentonite, silica gel, infusorial earth or zeolitic molecular sieves are used as adsorbing agent in the secondary extraction.

3. Process according to one of the above claims, characterized in that a mixture ratio primary extract :adsorbing agent of 1 : 0.1 to 1 : 10 is used.

4. Process according to one of the above claims, characterized in that with the secondary extraction with C0₂ in the extraction tank one works in supercritical pressure and temperature conditions, in subcritical pressure and temperature conditions or in supercritical pressure and subcritical temperature conditions.

5. Process according to one of the above claims, characterized in that with the secondary extraction with C0₂ in the separating tank the tension is relieved in subcritical pressure and temperature conditions.

6. Process according to one of the above claims, characterized in that a tobacco aromatic oil is extracted of which the nicotine content is reduced to 5 to 50 % relatively as compared with the nicotine content of the tobacco leaves prior to the primary extraction.

7. Process according to one of the above claims, characterized in that for the reduction of nicotine in the tobacco aromatic oil to 5 to 10 % relatively in comparison with the nicotine content of the tobacco leaves prior to the primary extraction, the secondary extraction with C0₂ is carried out in two stages :

a. A first extraction stage with C0₂ at a temperature of - 25 °C to + 5 °C and a pressure of approx. 20 to 25 bars in the extraction tank,

b. A second extraction stage with C0₂ by subsequent increase in pressure and temperature to over 25 bars and over 5 °C in the extraction tank.

8. Process according to Claim 7, characterized in that the tension is relieved in the separating tank in subcritical pressure and temperature conditions.

9. Process according to one of the above claims, characterized in that the secondary extraction with C0₂ is carried out for 0.5 to 8 hours.

10. Process according to one of the above claims, characterized in that with the secondary extraction CO₂ is used in a quantity of 0.3 to 35 kg/hour, corresponding to 1 kg tobacco from which the tobacco extract originates.

11. Process according to one of the above claims, characterized in that the product extracted with the secondary extraction in the separating tank is separated by filtration into resins and waxes on the one hand and clear tobacco aromatic oil on the other.

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