Improved method for producing liquid tobacco extract

Abstract

A method for producing a liquid tobacco extract includes preparing a tobacco material, heating the tobacco material at an extraction temperature of 120°C to 160°C for at least 90 minutes, collecting volatile compounds released from the tobacco material during the heating step, and forming a liquid tobacco extract containing the collected volatile compounds. The method further includes spraying atomized water into an extraction chamber during the heating step.

Description

Technical Field

[0001] The present invention relates to a method for producing a liquid tobacco extract and a liquid tobacco extract produced by such a method.

Background Art

[0002] An aerosol generation system for delivering an aerosol to a user, comprising an atomizer configured to generate an inhalable aerosol from a liquid formulation such as a liquid nicotine formulation, is known. Some known aerosol generation systems include a thermal atomizer, such as an electric heater, configured to heat and vaporize the liquid formulation to generate an aerosol. One popular type of electrically heated aerosol generation system is an electronic cigarette. Other known aerosol generation systems include a non-thermal atomizer configured to generate an aerosol from a liquid formulation using, for example, impinging jets, ultrasonic, or vibrating mesh technology.

[0003] Some methods for generating a liquid tobacco extract from tobacco material are known. The liquid tobacco extract can be produced by a high-temperature extraction process in which nicotine and other volatile flavor compounds are extracted from the tobacco material and collected in a suitable solvent to form a natural liquid tobacco extract.

[0004] A maceration method is also known in which the tobacco material is held in suspension in an extraction liquid for a period of up to several weeks or months. The resulting slurry is then filtered, and the liquid phase thus collected can be used to produce a vaporizable liquid formulation. In one such method, the so-called "cold maceration method", there is generally no way to control the extraction conditions (e.g., temperature and pressure). For example, in a variant of the maceration method described in US Patent No. 2012 / 192880, the slurry is heated to 100 degrees Celsius or more.

[0005] The liquid phase collected during slurry filtration corresponds to the primary product of the maceration process and tends to be highly diluted with a low content of nonpolar tobacco flavor varieties. Furthermore, the liquid phase usually contains little to no nicotine. Therefore, liquid extracts obtained by maceration generally need to be supplemented with additional components such as nicotine salts and glycerin before being used in vaporizable liquid formulations.

[0006] An alternative process is known in which tobacco material is substantially boiled in water for several hours or days to form a vapor phase, and the distillate obtained by the condensation of the vapor phase is continuously collected in a container. Over time, an oily, waxy layer containing a high proportion of nonpolar compounds accumulates on the surface of the distillate.

[0007] Meanwhile, a waxy layer accumulates, and the aqueous portion containing nicotine and other water-soluble compounds is recycled to the boiler. To increase the extraction yield, a nonpolar cosolvent may be optionally supplied to the boiler along with the aqueous portion. Meanwhile, the waxy phase is collected, ultimately forming one of the primary products of such a steam distillation process. These products are often referred to as "tobacco essential oil" and have a high proportion of nonpolar compounds present in tobacco, such as fatty acids and neophytadienes. Tobacco essential oil obtained by one such method typically does not contain nicotine.

[0008] Furthermore, tobacco materials are known to be subjected to extraction processes using volatile, nonpolar solvents. Examples of suitable solvents include cyclic or acyclic short alkanes and chlorinated solvents such as dichloromethane. In one such process, excess solvent can be evaporated by controlled heating under vacuum. Typically, this is done in the presence of ethanol, which has a higher boiling point than the extraction solvent, so that even trace amounts of the extraction solvent can be detected.

[0009] One primary product of such solvent-assisted extraction processes is often called "tobacco absolute" and may contain trace amounts of ethanol. This is a waxy product containing a high concentration mixture of most nonpolar compounds that can be extracted with a particular solvent, and generally contains nicotine, which is present in relatively high concentrations.

[0010] Alternative extraction processes involve contacting tobacco material with a solvent under supercritical conditions, such as supercritical carbon dioxide. One such process, disclosed in U.S. Patent No. 2013 / 160777, relies on the principle that volatile substances in the feed material can be separated into a supercritical phase upon contact with a supercritical fluid. After dissolving any soluble material, the supercritical fluid containing the dissolved substance can be removed, separating the dissolved components of the feed material from the supercritical fluid. The primary product of a supercritical extraction process is substantially similar to a "tobacco absolute" from a solvent-assisted extraction process performed at lower temperatures and pressures, contains no residual solvent, typically has high levels of waxy, nonpolar compounds, and generally contains nicotine, which is present in relatively high concentrations.

[0011] However, all tobacco extracts obtained by methods known in the art tend to have very low levels, if any, of compounds associated with the flavor of heated tobacco, such as furaneol.

[0012] Generally, as discussed above, liquid tobacco extracts obtained by these known extraction processes may contain low levels of nicotine. Furthermore, liquid tobacco extracts obtained by these extraction processes may have low levels and a limited variety of flavors. Liquid tobacco extracts obtained by these extraction processes may also have high levels of undesirable compounds. Generally, the concentrations of nicotine, flavors, and undesirable compounds obtained by these extraction processes can be significantly influenced by the type or combination of tobaccos used as starting materials.

[0013] The object of the present invention is to mitigate one or more drawbacks of liquid tobacco extracts obtained by known processes. In particular, it would be desirable to provide a method for producing novel and improved liquid tobacco extracts. It would be especially desirable to provide a method for producing liquid tobacco extracts that can be carried out more efficiently than existing processes. [Overview of the project]

[0014] This disclosure relates to a method for producing a liquid tobacco extract from tobacco material. The method may include a step of preparing the tobacco material. The tobacco material may be heated in an extraction chamber at an extraction temperature of about 120° to about 160°C. The heating may be carried out for at least 90 minutes. The method may further include a step of collecting volatile compounds released from the tobacco material during the heating step. The method may further include a step of forming a liquid tobacco extract containing the collected volatile compounds. The method may further include a step of spraying atomized water into the extraction chamber during the heating step.

[0015] The present invention provides a method for producing a liquid tobacco extract, the method comprising the steps of: preparing tobacco material; heating the tobacco material in an extraction chamber at an extraction temperature of approximately 120°C to approximately 160°C for at least approximately 90 minutes; collecting volatile compounds released from the tobacco material during the heating step; and forming a liquid tobacco extract containing the collected volatile compounds. The present invention further provides a step of spraying atomized water into the extraction chamber during the heating step.

[0016] According to the present invention, a liquid tobacco extract produced by the method of the present invention as defined above is further provided.

[0017] As used herein in connection with the present invention, the term “liquid tobacco extract” refers to the direct product of an extraction process performed on tobacco material. Therefore, tobacco extracts typically contain a mixture of natural components separated from, removed from, or derived from natural tobacco material using tobacco extraction processing conditions and techniques. Thus, in one such process, extracted tobacco components are removed from natural tobacco material and separated from unextracted tobacco components. According to the present invention, an extraction process for producing a liquid tobacco extract comprises heating tobacco material under specific heating conditions and collecting the resulting volatile compounds. Thus, a liquid tobacco extract consists of a mixture of natural tobacco components derived from tobacco material and extracted or formed during the extraction process, typically combined with one or more materials other than tobacco material, such as a non-aqueous extraction solvent used during the extraction process. As will be described in more detail below, volatile compounds released from the starting tobacco material can be collected using absorption techniques in which the volatile compounds are trapped in the non-aqueous extraction solvent. As an example, an inert gas stream containing the volatile compounds may be directed into a container of the non-aqueous extraction solvent. The non-aqueous extraction solvent is preferably an aerosol-forming agent.

[0018] As used herein in connection with the present invention, the term “atomized water” refers to water reduced to a plurality of small liquid droplets. Thus, atomized water is an aerosolized form having a plurality of water droplets suspended in air or another gas. In connection with the method of the present invention, the term “spray” refers to the process of discharging a stream or flow of atomized water into an extraction chamber at atmospheric pressure or above.

[0019] Therefore, the present invention provides a novel heating step in which atomized water is sprayed into the extraction chamber during the process of heating tobacco material to extract volatile compounds. In prior art extraction processes, it is common to dry the tobacco material before the heating step, which was thought to save the drying effort and yield a more concentrated extract. However, the inventors of the present invention have surprisingly found that including the water spraying step defined above significantly improves the extraction yield of specific components and outweighs any dilution effect.

[0020] In particular, it was unexpectedly found that including a water spraying step significantly increased the yield of nicotine and other flavor compounds during extraction. For example, in certain cases, including a water spraying step was found to increase the nicotine extraction yield by up to 130% compared to equivalent extraction performed without water spraying.

[0021] This improvement in extraction yield was found to be particularly related to the use of atomized water spray. As shown in the comparative examples below, a similar improvement in nicotine yield was not observed when water was added directly to the tobacco material before the heating step, or when water or vapor was added to the extraction chamber without atomization. Without being bound by theory, the improvement in extraction yield is thought to be due to the turbulent gas flow generated in the extraction chamber as the droplets of the atomized water spray evaporate, thereby improving heat exchange. In particular, the high gas velocity generated at a microscale level while the atomized water droplets expand into the gas phase is thought to strongly influence the behavior of the tobacco surface, promoting increased mass transfer of volatile compounds such as nicotine. This allows for more effective extraction of nicotine and certain other volatile compounds from the tobacco material, resulting in an improved extraction yield.

[0022] The equipment necessary for the water spray process is readily available and can be incorporated into existing extraction equipment without significant modifications.

[0023] In addition to improving nicotine yield, the extraction method of the present invention, by using an extraction temperature within a specific range in combination with a particularly defined heating time, advantageously provides an improved liquid tobacco extract with a significantly improved balance between desirable and undesirable compounds. In particular, the extraction method of the present invention provides a liquid tobacco extract in which the ratio of undesirable compounds to desirable compounds for tobacco material is maximized. For example, by using a specific combination of defined extraction temperature and time, the level of nicotine compounds can be optimized while simultaneously minimizing the levels of undesirable compounds such as furan, carbonyl, phenol, and TSNA.

[0024] The inventors of the present invention have found that, in contrast to the existing extraction processes described above, the method according to the present invention advantageously provides a liquid tobacco extract with a significantly higher content of compounds associated with the flavor of heated tobacco, such as furaneol. These compounds are substantially absent or present in trace amounts in tobacco extracts obtained by maceration processes and typically contain little to no nicotine. These compounds are also generally absent or present in trace amounts in tobacco extracts obtained using solvents, including under supercritical conditions. Similarly, tobacco essential oils obtained by distillation processes also typically contain very low levels, if any, of such compounds associated with the flavor of heated tobacco.

[0025] The liquid tobacco extract obtained by the method according to the present invention exhibits significant compositional differences compared to tobacco extracts obtained by existing extraction processes and can be used as an electronic liquid or, when heated, to produce an aerosol having a different composition and flavor characteristics from currently available electronic liquids. In particular, the liquid tobacco extract obtained by the method according to the present invention can be used to produce an aerosol that provides a heated tobacco taste more similar to the aerosol produced by conventional tobacco or the aerosol produced when tobacco is heated in a non-combustible heating device, compared to the available aerosol produced from existing liquid nicotine compositions.

[0026] The extraction method of the present invention enables the production of a liquid tobacco extract having an optimized level of nicotine and flavor compounds without adding such compounds after extraction. Thus, the resulting liquid tobacco extract can be advantageously used directly to provide a nicotine composition. The resulting liquid tobacco extract may also be modified by one or more additional processing steps or mixed with one or more additional components to form a nicotine composition. The nicotine composition may be for use in an electronic cigarette or other aerosol generating system.

[0027] As described above, an aerosol generating system for delivering an aerosol to a user is known, comprising an atomizer configured to generate an inhalable aerosol from a liquid formulation such as a liquid nicotine composition.

[0028] The method for producing the liquid tobacco extract of the present invention can be effectively used for all types of tobacco and grades, including Burley tobacco, fire-cured tobacco, and Oriental leaf tobacco. The steps of the method can be easily adjusted to provide a consistent liquid tobacco extract for various blends of tobacco types. The extraction method is further suitable for various forms of tobacco material.

[0029] In some cases, the tobacco material can be heated without requiring significant pre-treatment steps. Thus, the method can be efficiently implemented.

[0030] As defined above, in the method of the present invention, the tobacco material is heated under specific heating conditions to release volatile tobacco components, which are collected and formed into a liquid tobacco extract.

[0031] During the heating process, the tobacco material is heated to an extraction temperature of approximately 120°C to 160°C. Below this range, insufficient concentrations of nicotine and certain flavor compounds are released from the tobacco material, resulting in a liquid tobacco extract lacking the desired flavor characteristics. On the other hand, if the tobacco material is heated to a temperature above this defined range, unacceptably high levels of certain undesirable tobacco compounds may be released.

[0032] Preferably, the extraction temperature is at least 125 degrees Celsius, more preferably about 130 degrees Celsius.

[0033] Preferably, the extraction temperature is less than approximately 155 degrees Celsius, more preferably less than approximately 150 degrees Celsius.

[0034] For example, the extraction temperature may be approximately 125°C to 155°C, or approximately 130°C to 150°C. An extraction temperature of approximately 150°C has been found to provide a particularly optimized ratio of desirable to undesirable compounds in the liquid tobacco extract.

[0035] The tobacco starting material is heated at a certain extraction temperature for at least about 90, more preferably at least about 120 minutes. This extraction time is long enough to efficiently extract the desired tobacco flavor compounds and provide a liquid tobacco extract capable of producing an aerosol having the desired flavor characteristics.

[0036] The tobacco starting material is preferably heated at the extraction temperature for about 270 minutes or less, more preferably for about 180 minutes or less.

[0037] For example, the tobacco starting material may be heated for approximately 90 to 270 minutes, or approximately 120 to 180 minutes.

[0038] The heating time shown above corresponds to the duration of time the tobacco material is heated to the extraction temperature, and does not include the time required to raise the temperature of the tobacco material to the extraction temperature.

[0039] The extraction temperature and heating time may be selected within the range defined above, depending on factors such as the type of tobacco, other possible components of the tobacco material, the desired level of nicotine, or the desired composition of the liquid tobacco extract. By controlling the combination of extraction temperature and time, the composition of the liquid tobacco extract can be adjusted according to the desired properties of the aerosol produced from the liquid tobacco extract. In particular, the proportion of specific tobacco compounds in the liquid tobacco extract can be adjusted to some extent through the selection of extraction parameters in order to maximize the ratio of desirable to undesirable tobacco compounds in the liquid tobacco extract.

[0040] For certain tobacco compounds, the variation in compound release levels with respect to extraction temperature during the extraction process can be easily determined for any given tobacco material. For example, it has been shown that the level of nicotine released from tobacco material typically increases with increasing extraction temperature. The rate of increase has been found to vary depending on the type of tobacco.

[0041] Furthermore, it has been found that the levels of desirable tobacco flavor compounds, such as β-damascenone and β-ionone, released from tobacco material increase as the extraction temperature rises to a specific peak extraction temperature, after which the levels begin to decrease. The peak extraction temperature for such flavor compounds is typically in the range of 120°C to 160°C, so that the extraction method of the present invention can effectively optimize the levels of desirable flavor compounds.

[0042] Many undesirable tobacco compounds have been found to increase slowly as the extraction temperature rises to a threshold temperature, and then rapidly increase beyond that point. This applies, for example, to the levels of phenolic compounds, TSNA, and pyrazines, and to the levels of furan and formaldehyde in the case of bright tobacco. In many cases, the threshold temperature is in the range of 120°C to 160°C, and therefore, the levels of undesirable compounds can be effectively controlled in the extraction method of the present invention.

[0043] Preferably, the extraction temperature and extraction time are selected to provide a nicotine content in the liquid tobacco extract of at least 0.1 weight percent, more preferably at least about 0.2 weight percent.

[0044] Preferably, the extraction temperature, or the extraction time, or both, is selected to provide a weight ratio of at least about 0.25 (β-ionone + β-damascenone) to (phenol) in the liquid tobacco extract.

[0045] β-Damascenone and β-Ionone are desirable compounds associated with tobacco flavor. It has also been found that the amounts of β-Damascenone and β-Ionone released from tobacco material increase as the extraction temperature rises to a certain peak extraction temperature, after which the levels begin to decrease. The peak extraction temperature for such flavor compounds is typically in the range of 120°C to 160°C, so that the extraction method can effectively adjust and control the levels of the desired flavor compounds.

[0046] Preferably, the extraction temperature, or the extraction time, or both the extraction temperature and extraction time, are at least about 5 x 10 in the liquid tobacco extract. -4 Selected to provide a weight ratio of (furaneol + (2,3-diethyl-5-methylpyrazine)*100) to (nicotine).

[0047] In the method according to the present invention, where the extraction temperature is selected to provide a ratio within the range described above, it has been found that a particularly good sensory profile can be achieved when heating a nicotine composition prepared from a liquid tobacco extract to generate an aerosol.

[0048] Suitable heating methods for heating tobacco materials are known to those skilled in the art and include, but are not limited to, dry distillation, steam distillation, vacuum distillation, flash distillation, and thin-film steam distillation.

[0049] As described above, according to the present invention, atomized water is sprayed into the extraction chamber during the heating process. Preferably, the atomized water is sprayed into the extraction chamber to generate a turbulent gas flow within the extraction chamber.

[0050] It is preferable to start the spraying when the desired extraction temperature, within a predetermined range of 120°C to 160°C, is reached in the extraction chamber.

[0051] A spray of atomized water can be generated using any suitable means and discharged into the extraction chamber. The spray of atomized water can be generated from a single spray nozzle directed into the extraction chamber, or from multiple spray nozzles provided at different locations around the extraction chamber. The spray nozzles can be adapted to provide a desired type of spray, e.g., a jet or mist of atomized water.

[0052] Atomized water can be continuously sprayed into the extraction chamber during the heating process, or it can be intermittently sprayed into the extraction chamber during the heating process. Spraying can be continued for the entire heating process, or performed for only a portion of the heating process. For example, spraying can be stopped when a defined maximum amount of water has been sprayed into the extraction chamber.

[0053] The flow rate at which atomized water is sprayed into the extraction chamber can be adjusted, for example, according to the flow rate of tobacco material in the extraction chamber. For example, the average flow rate at which atomized water is sprayed into the extraction chamber may be about 3 percent to about 30 percent of the flow rate of tobacco material, more preferably about 5 percent to about 20 percent, and more preferably about 7.5 percent to about 15 percent. The flow rate at which atomized water is sprayed into the extraction chamber may also need to be controlled according to other parameters, such as the desired total amount of water sprayed into the extraction chamber during the heating process.

[0054] By maintaining the water flow rate at 30% or less of the tobacco flow rate, it is ensured that the amount of water sprayed into the extraction chamber does not increase, preventing significant energy loss due to the evaporation of atomized water and thus preventing the temperature inside the extraction chamber from being maintained. Furthermore, maintaining the water flow rate sprayed into the extraction chamber at or below this level prevents the tobacco material from becoming too sticky and agglomerating, which would negatively affect extraction efficiency.

[0055] Preferably, the atomized water is sprayed into the extraction chamber at an average flow rate of at least about 0.2 grams / second, more preferably at least about 0.4 grams / second, and more preferably at least about 0.6 grams / second.

[0056] Preferably, the atomized water is sprayed into the extraction chamber at an average flow rate of less than about 1.6 grams / second, more preferably less than about 1.4 grams / second, and more preferably less than about 1.2 grams / second. For example, the atomized water may be sprayed into the extraction chamber at a flow rate of about 0.2 grams / second to about 1.6 grams / second, or about 0.4 grams / second to about 1.4 grams / second, or about 0.6 grams / second to about 1.2 grams / second.

[0057] These flow rate values ​​refer to the average flow rate throughout the duration of the heating process. If atomized water is sprayed intermittently during the heating process, the actual flow rate during intermittent spraying will be higher than the average flow rate.

[0058] Preferably, the atomized water is sprayed at a pressure of at least about 1 bar, more preferably at least about 2 bar, and more preferably at least about 3 bar.

[0059] Preferably, the atomized water is at room temperature (22 degrees Celsius) when it is sprayed into the extraction chamber. Since the temperature inside the extraction chamber is at least 120 degrees Celsius, the atomized water evaporates rapidly inside the extraction chamber.

[0060] The shape of the atomized water spray can be adapted through the selection of a spray nozzle device. Preferably, the atomized water is sprayed in a conical shape to disperse the atomized water as much as possible through the internal space of the extraction chamber. Alternatively, the sprayed water may be sprayed into the extraction chamber as a mist, without a defined shape.

[0061] The direction of the atomized water spray can be adapted through the selection of the position and orientation of the spray nozzle. Preferably, the atomized water is sprayed approximately parallel to the flow of tobacco in the extraction chamber.

[0062] Methods for atomizing water will be known to those skilled in the art. In some embodiments, water can be atomized by a flow of compressed inert gas, such as air. In other embodiments, water can be atomized without a gas flow due to the pressure within the spray nozzle.

[0063] The tobacco material is preferably circulated or agitated during the heating process to optimize the effect of atomized water spraying. This can be achieved, for example, by providing a flow of inert gas through the tobacco material during heating, as described below. Alternatively, or additionally, the heating process may be carried out in an extraction chamber adapted to keep the tobacco material moving, such as a rotary dryer.

[0064] The heating process is preferably carried out in an inert atmosphere. It is preferable that a flow of an inert gas, such as nitrogen, passes through the tobacco material during the heating process. In some cases, a combination flow of an inert gas and water or vapor may be used. Adding water or vapor to the tobacco during extraction has been found to increase the yield of extracted components. However, adding too much water or vapor can lead to processing difficulties such as stickiness of the tobacco material.

[0065] The volatile tobacco compounds are released into a stream of inert gas during the heating step, so that the inert gas acts as a carrier for the volatile components. The flow rate of the inert gas may be optimized based on the size and geometric shape of the extraction chamber. A relatively high flow rate of the inert gas can favorably improve the efficiency of extraction from the tobacco material.

[0066] Generally, when tobacco material is heated, any moisture present in the tobacco material is also released along with volatile compounds in the form of vapor.

[0067] The flow of inert gas helps to remove vapors produced by the evaporation of moisture from the tobacco material, and volatile compounds, particularly nicotine or flavor-related compounds, or both, from the extraction equipment.

[0068] Furthermore, the use of an inert gas (such as nitrogen) flow under slight overpressure within the extraction equipment has the advantage of preventing the presence of oxygen within the equipment. This is desirable in that it prevents the risk of the tobacco material burning, even partially, during the heating process. Uncontrolled combustion of tobacco material is obviously undesirable as it would pose a major safety risk in the manufacturing environment. However, the inventors have found that even limited and partial combustion of tobacco material can lead to a decrease in the quality of the tobacco extract obtainable by this method (which would be undesirable).

[0069] While we do not wish to be bound by theory, it is understood that preventing the combustion of tobacco material also prevents the formation of any undesirable combustion byproducts. Furthermore, by preventing conditions that would promote the combustion of tobacco material, the tobacco material is effectively heated under conditions that, to some extent, mimic the conditions under which tobacco-containing substrates (e.g., homogenized tobacco material) are typically heated in "heated non-combustible" articles. As a result, it is advantageously supported for consumers to selectively extract volatile species that contribute to the flavor associated with heated tobacco.

[0070] Therefore, performing the heating process in an inert atmosphere advantageously enhances extraction efficiency, product quality, and manufacturing safety.

[0071] Heating tobacco material in an inert gas flow has the additional benefit that the flow of inert gas containing volatile compounds can be more easily directed towards a container containing an extraction solvent, such as a non-aqueous extraction liquid solvent.

[0072] Optionally, the heating process may be carried out under vacuum. This removes any oxygen present in the extraction chamber, which is advantageous as it can prevent the reaction of the tobacco material or volatile compounds produced during heating of the tobacco material with oxygen. The removal of oxygen also prevents any combustion of the tobacco material, as described above.

[0073] Preferably, as a result of the extraction method of the present invention including a water spraying step, the amount of nicotine extracted from the tobacco material during the heating step corresponds to at least about 2 g per 1 kg of dry tobacco material, and more preferably at least about 2.2 g per 1 kg of dry tobacco material. This amount of extracted nicotine is significantly higher than that obtained using an equivalent extraction method (without the spraying step), as shown in the following example.

[0074] Liquid tobacco extracts can be produced from tobacco material consisting of a single type of natural tobacco. Alternatively, the tobacco material may contain a blend of two or more types of natural tobacco. The ratio of different tobacco types can be adjusted according to the desired characteristics of the aerosol produced from the liquid tobacco extract. For example, if it is desired to provide a relatively high level of nicotine, the proportion of Burley tobacco can be increased.

[0075] The term “natural tobacco” is used herein to describe any part of any plant member of the genus Nicotiana, including but not limited to leaves, midribs, stems, and petioles, in relation to the present invention. In particular, natural tobacco may include fire-dried tobacco material, Burley tobacco material, Oriental leaf tobacco material, Maryland tobacco material, dark tobacco material, dark fire-dried tobacco material, Rustica tobacco material, and other rare or specialty tobacco-derived materials, or blends thereof. As will be described in more detail below, tobacco material may be whole (e.g., whole tobacco leaves), or shredded, cut, or ground.

[0076] If it is desired to produce a liquid tobacco extract from a combination of two or more different types of tobacco, the types of tobacco may be heated separately at different extraction temperatures within a defined range of 100 to 160 degrees Celsius, or the mixture of tobacco types may be heated together at a single extraction temperature within that range.

[0077] The tobacco material may be a solid tobacco material such as powder, leaf scraps or fragments, or intact leaves. Alternatively, the tobacco material may be a liquid tobacco material such as dough, gel, slurry, or suspension.

[0078] The tobacco material may be derived from any suitable tobacco material, including but not limited to tobacco leaves, tobacco stems, reconstituted tobacco, cast tobacco, extruded tobacco, or tobacco-derived pellets.

[0079] In the process of preparing tobacco material, it is preferable that the tobacco be crushed or cut in order to reduce the size of the tobacco particles in the tobacco material. This may be advantageous in that it can improve the homogeneity of heating the tobacco material and the efficiency of extraction.

[0080] The tobacco material may be optionally dried before the heating step to reduce its moisture content. Drying of the tobacco material may be carried out by any suitable chemical or physical drying process. Alternatively, water may be added to the tobacco material before the heating step to increase its moisture content.

[0081] In certain embodiments of the present invention, the step of preparing a tobacco material may include the step of impregnating the tobacco material with an aerosol-forming agent. If this impregnation of the tobacco material is performed before the heating step, this may advantageously increase the amount of certain desirable tobacco compounds released from the tobacco material upon heating. For example, impregnation of the tobacco material with glycerin has been shown to advantageously increase the amount of nicotine extracted from the tobacco material. In another embodiment, impregnation of the tobacco material with a non-aqueous extraction solvent, which is also an aerosol-forming agent such as propylene glycol, vegetal glycerin, 1,3-propanediol, triacetin, or a mixture thereof, has been found to advantageously increase the amount of flavor compounds extracted from the tobacco material.

[0082] Alternatively or additionally, the tobacco material may contain one or more additional components, such as a non-aqueous solvent. An example of a suitable solvent is propylene glycol.

[0083] Therefore, the tobacco material may contain at least about 40 weight percent of natural tobacco material, or at least about 60 weight percent of natural tobacco material, or at least about 80 weight percent of natural tobacco material, or at least about 90 weight percent of natural tobacco material, or at least about 95 weight percent of natural tobacco material.

[0084] The moisture content of the tobacco starting material may be at least about 3 weight percent. Preferably, the moisture content of the tobacco starting material is at least about 5 weight percent. More preferably, the moisture content of the tobacco starting material is at least about 5 weight percent. Naturally, the "moisture content in the tobacco starting material" may include both water that is essentially present in the natural tobacco material and any added water.

[0085] The moisture content of the tobacco starting material may be about 60 weight percent or less. Preferably, the moisture content of the tobacco starting material is about 20 weight percent or less. More preferably, the moisture content of the tobacco starting material is about 12 weight percent or less.

[0086] In some embodiments, the moisture content of the tobacco starting material may be about 3% to about 60% by weight, more preferably about 3% to about 20% by weight, and even more preferably about 3% to about 12% by weight. In other embodiments, the moisture content of the tobacco starting material may be about 5% to about 60% by weight, more preferably about 5% to about 20% by weight, and even more preferably about 5% to about 12% by weight. In further embodiments, the moisture content of the tobacco starting material may be about 8% to about 60% by weight, more preferably about 8% to about 20% by weight, and even more preferably about 8% to about 12% by weight.

[0087] In some embodiments, the non-aqueous solvent content may be at least about 5 weight percent, or at least about 10 weight percent, or at least about 15 weight percent, or at least about 20 weight percent, or at least about 25 weight percent, or at least about 30 weight percent, or at least about 35 weight percent, or at least about 40 weight percent.

[0088] Optionally, the tobacco material may be enzymatically digested before the heating process. This has been shown to provide a significant increase in the yield of certain flavor compounds from the tobacco material.

[0089] In certain embodiments, it is preferable that, in the process of preparing the tobacco material, the tobacco is not subjected to any treatment adapted to change the pH of the tobacco. In particular, in the process of preparing the tobacco material, the tobacco is not subjected to any treatment adapted to significantly increase the pH of the tobacco.

[0090] In other embodiments, the method further includes a step of alkali treatment of the tobacco material prior to the heating step. If the method includes a pretreatment step of the tobacco material before microwave heating, the alkali treatment is preferably carried out before microwave heating. During the alkali treatment, preferably, an alkaline solution is applied to the tobacco material to provide alkalized tobacco material, which is then used for extraction.

[0091] It was found that including an alkaline treatment step before heating the tobacco material resulted in a further significant increase in the yield of nicotine obtained during extraction.

[0092] Preferably, the pH of the alkalized tobacco material is at least about 8.5, more preferably at least about 9.0, and more preferably at least about 9.5. Preferably, the pH of the alkalized tobacco material is 11 or less.

[0093] "pH of alkalized tobacco material" refers to the pH of an aqueous suspension of alkalized tobacco material, formed by suspending the alkalized tobacco material in water at a ratio of 1:20. The pH of the suspension is measured after a 30-minute immersion time.

[0094] As described above, in the alkali treatment step, an alkaline solution is applied to the tobacco material before heating. A suitable alkaline solution may be selected, for example, depending on the desired pH of the tobacco material. The alkaline solution is preferably an aqueous solution of an alkaline agent. A preferred example of an alkaline solution suitable for the alkali treatment step is an aqueous solution of potassium carbonate. Other suitable alkaline solutions for use in the present invention include, but are not limited to, sodium hydroxide, sodium carbonate, and hydrogen peroxide.

[0095] The tobacco material may optionally be analyzed before the heating step to determine its composition, for example, the content of reducing sugars such as alkaloids. This information regarding the composition can be useful in selecting an appropriate extraction temperature.

[0096] The method according to the present invention may further include a step of microwave heating of tobacco material during at least one step of the method. The tobacco material may be microwave heated before the heating step, during the pretreatment step. Alternatively or additionally, the tobacco material may be microwave heated during the main heating step, in place of or in combination with conventional heating.

[0097] It has been found that including a microwave heating step in the extraction method of the present invention leads to a further improvement in nicotine extraction yield.

[0098] During heating of tobacco material, volatile compounds are released from the tobacco material in gaseous form. These volatile compounds are collected using any suitable technique. If, as described above, the tobacco material is heated in a flow of inert gas, the volatile compounds are collected from the inert gas flow. Different collection methods will be well known to those skilled in the art.

[0099] In certain preferred embodiments, the step of collecting volatile compounds employs an absorption technique to confine the volatile compounds in a non-aqueous extractive liquid solvent. For example, an inert gas stream containing the volatile compounds may be directed into a container of the non-aqueous extractive liquid solvent. The non-aqueous extractive liquid solvent is preferably an aerosol-forming agent such as triacetin, glycerin, 1,3-propanediol, propylene glycol, or a combination thereof. Using an aerosol-forming agent as the liquid solvent is potentially beneficial because the aerosol-forming agent can be retained as a diluent in the final liquid tobacco extract. This means that an additional step to remove the non-aqueous extractive solvent is not necessarily required.

[0100] As used herein in relation to the present invention, the term “aerosol-forming compound” refers to a compound or mixture of compounds that facilitates aerosol formation in use and is preferably substantially resistant to thermal decomposition at the operating temperature of the aerosol-generating article or apparatus. Examples of suitable aerosol-forming compounds include polyhydric alcohols (such as propylene glycol, triethylene glycol, 1,3-propanediol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic acids, dicarboxylic acids, or polycarboxylic acids (such as dimethyl dodecanediate and dimethyl tetradecanediate).

[0101] Non-aqueous liquid solvents are preferably maintained at a temperature below 0 degrees Celsius to optimize the transfer of volatile compounds into the liquid solvent. Non-aqueous extraction solvents are preferably maintained at a temperature of -10 degrees Celsius or higher. Temperatures below these values ​​may result in undesirable freezing.

[0102] In alternative, preferred embodiments, the step of collecting volatile compounds may be carried out using a condensation technique in which the volatile compounds are condensed and the condensate is collected. The condensation of volatile compounds may be carried out, for example, using any suitable apparatus in a cooling column. Preferably, the resulting condensate is added to a liquid aerosol former, preferably propylene glycol.

[0103] The addition of a liquid aerosol-forming agent, particularly propylene glycol, during the collection process can advantageously prevent condensed volatile compounds from separating into two phases or forming emulsions, as is the case with some tobacco components. While not intended to be theoretically bound, the inventors observed that the solubility of tobacco components in aqueous extracts (hydrolates) (i.e., aqueous fractions of naturally derived liquid tobacco extracts) depends primarily on their polarity, concentration, and the pH of the aqueous extract (hydrolate), which can vary depending on the type of tobacco. Consequently, if the amount of aerosol-forming agent is insufficient, an oily layer tends to form on the surface of the naturally derived liquid tobacco extract. Such oily substances can aggregate at different locations in the capture and drying equipment, where the third and subsequent steps of the method are carried out, respectively. The addition of a liquid aerosol-forming agent, such as propylene glycol, helps prevent the formation of such layers and is advantageous for homogenizing the naturally derived liquid tobacco extract. This, in turn, helps prevent the loss of desirable flavor-related compounds during the fourth (drying) step, during which time these compounds may unnecessarily accumulate on the equipment surface.

[0104] Furthermore, the liquid aerosol form, regardless of its polarity and volatility, is advantageous in capturing flavor-related compounds. Moreover, during any subsequent drying process, the liquid aerosol form helps prevent the loss of the most volatile fractions and is advantageous in selectively removing excess water from naturally derived liquid tobacco extracts to obtain concentrated tobacco extracts.

[0105] The use of propylene glycol as an aerosol former in the collection process has the added advantage that propylene glycol exerts antimicrobial activity by reducing the water activity of the aqueous solution. Therefore, by adjusting the propylene glycol content in the liquid tobacco extract, it is possible to ensure that the extract is virtually free from microbial activity.

[0106] As a further alternative, the process of collecting volatile compounds can be carried out using adsorption techniques in which the volatile compounds are adsorbed onto the surface of a solid adsorbent material such as activated carbon. The adsorbed compounds are then transferred into a liquid solvent.

[0107] In the method of the present invention, the next step is to form a liquid tobacco extract from the collected volatile compounds. The nature of this step may depend on the collection method. The "collected volatile compounds" typically include a solution of tobacco-derived volatile compounds in a liquid solvent or carrier.

[0108] As described above, when volatile compounds are collected by absorption in a non-aqueous extraction solvent, the extraction method provides a liquid tobacco extract that may contain more than about 25 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. In some embodiments, the liquid tobacco extract may contain more than about 30 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract, or more than about 35 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract.

[0109] The liquid tobacco extract may contain about 65 percent or less of a non-aqueous extraction solvent based on the weight of the liquid tobacco extract. In some embodiments, the liquid tobacco extract may contain 60 percent or less of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract, or 55 percent or less of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract.

[0110] In some embodiments, the liquid tobacco extract may comprise about 25 weight percent to about 65 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. The liquid tobacco extract may comprise about 25 weight percent to about 60 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. The liquid tobacco extract may comprise about 25 weight percent to about 55 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract.

[0111] In other embodiments, the liquid tobacco extract may comprise about 30 weight percent to about 65 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. The liquid tobacco extract may comprise about 30 weight percent to about 60 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. The liquid tobacco extract may comprise about 30 weight percent to about 55 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract.

[0112] In further embodiments, the liquid tobacco extract may comprise about 35 weight percent to about 65 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. The liquid tobacco extract may comprise about 35 weight percent to about 60 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. The liquid tobacco extract may comprise about 35 weight percent to about 55 weight percent of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. The non-aqueous extraction solvent is preferably triacetin, glycerin, propylene glycol, 1,3-propanediol, or a mixture thereof.

[0113] In a preferred embodiment, the weight ratio of (β-ionone + β-damascenone) to (phenol) in the liquid tobacco extract is at least about 0.25.

[0114] In a preferred embodiment, the weight ratio of (furaneol + (2,3-diethyl-5-methylpyrazine)*100) to (nicotine) in the liquid tobacco extract is at least about 5 x 10 -4 That is the case.

[0115] As described above, when volatile compounds are collected by absorption in a liquid solvent, the step of forming a liquid tobacco extract preferably includes drying the solution of volatile compounds in the liquid solvent to concentrate the solution. This may be done, for example, to reach a desired concentration of nicotine or flavor compounds. Drying may be carried out using any suitable means, including but not limited to desiccation, molecular sieving, freeze-drying, phase separation, distillation, membrane permeation, controlled crystallization and filtration of water, reverse hygroscopicity, ultracentrifugation, liquid chromatography, reverse osmosis, or chemical drying.

[0116] In a preferred embodiment, the solution of the volatile compound in the liquid solvent is concentrated by drying.

[0117] In other words, a concentrated tobacco extract is obtained by heating a solution of volatile compounds in a liquid solvent to evaporate at least some of the water. For this purpose, the solution of volatile compounds in a liquid solvent may be heated to a certain temperature and for a certain period of time such that the water content in the tobacco extract is reduced by at least about 60 percent.

[0118] A partially dried concentrated tobacco extract can be considered a primary product of the method according to the present invention. Depleted tobacco material, from which most of the volatile species and moisture content have been extracted during heating in the second step, can be considered a by-product of the method. Such depleted tobacco material may typically have a moisture content of about 1 to 5 weight percent, preferably about 2 to 3 weight percent.

[0119] In one embodiment, a solution of a volatile compound in a liquid solvent is heated under vacuum, preferably at a temperature of at least about 70 degrees Celsius. In another embodiment, a solution of a volatile compound in a liquid solvent is heated under an airflow, preferably an airflow with relatively low humidity, at a temperature of at least about 35 degrees Celsius. Thus, a concentrated tobacco extract of natural origin can be obtained by the method according to the present invention. One such concentrated tobacco extract of natural origin typically contains less than about 20 percent by weight of water.

[0120] Alternatively, if volatile compounds are collected by condensation, the step of forming a liquid tobacco extract may include adding the condensate to a liquid solvent such as an aerosol-forming agent.

[0121] The process of forming a liquid tobacco extract may optionally include a filtration step.

[0122] Optionally, the process of forming a liquid tobacco extract may include a blending process in which extracts derived from different tobacco materials are combined.

[0123] Optionally, the process of forming a liquid tobacco extract may involve adding one or more additives, such as organic acids, to a solution of volatile compounds. However, in many cases, liquid tobacco extracts are suitable for use without additives.

[0124] The present invention further provides liquid tobacco extracts produced by the method according to the first aspect of the present invention, as described in detail above. As described above, the method of the present invention advantageously produces natural liquid tobacco extracts having a very desirable ratio of desired tobacco compounds, such as nicotine and flavor compounds, to undesirable tobacco compounds.

[0125] Liquid tobacco extracts are particularly suitable for producing nicotine compositions, such as liquid nicotine compositions or gel nicotine compositions, for use in aerosol generating systems. In such aerosol generating systems, the nicotine composition is typically heated within the aerosol generating device.

[0126] As used herein, the term “aerosol generator” refers to a device comprising a heater element that interacts with a nicotine composition incorporating a liquid tobacco extract, such as by the method according to the present invention to produce an aerosol. During use, volatile compounds are released from the nicotine composition by heat transfer and taken into the air drawn through the aerosol generator. As the released compounds cool, they condense to form an aerosol, which is inhaled by the consumer.

[0127] Upon heating of the nicotine composition containing the liquid tobacco extract according to the present invention, an aerosol containing volatile compounds collected from the tobacco material during the extraction process is released. By controlling the composition of the liquid tobacco extract through the control of extraction parameters, it is possible to adjust the composition and properties of the resulting aerosol produced from the liquid tobacco extract and delivered to the consumer.

[0128] The nicotine composition may be a liquid tobacco extract obtained from the extraction process according to the present invention without the addition of further nicotine. The nicotine composition may be a liquid tobacco extract obtained from the extraction process according to the present invention without the addition of further flavor compounds. The nicotine composition may be a liquid tobacco extract obtained from the extraction process according to the present invention without the addition of further furaneol. The nicotine composition may be a liquid tobacco extract obtained from the extraction process according to the present invention without the addition of further solvents.

[0129] Alternatively, the liquid tobacco extract may be subjected to additional processing steps to form a nicotine composition. Even when subjected to such additional steps, the nicotine composition can be formed without the need to add further nicotine or flavoring compounds.

[0130] Preferably, the liquid tobacco extract may be concentrated in the drying step described above to form a concentrated tobacco extract, and the concentrated tobacco extract may be used to form a nicotine composition.

[0131] Preferably, the concentrated tobacco extract contains 8% to 15% by weight of water, based on the weight of the concentrated tobacco extract.

[0132] The drying step provides a concentrated tobacco extract that may have a non-aqueous extraction solvent content of about 65% to about 95% by weight, preferably about 65% to 85% by weight, and most preferably about 75% to about 85% by weight. The non-aqueous extraction solvent is preferably triacetin, glycerin, propylene glycol, 1,3-propanediol, or a mixture thereof.

[0133] The drying process provides a concentrated tobacco extract that may have a nicotine content of at least about 0.2 weight percent of nicotine, preferably about 0.5 weight percent to about 12 weight percent of nicotine, and most preferably about 2 weight percent to about 8 weight percent of nicotine.

[0134] Preferably, an additional non-aqueous solvent may be added to the liquid tobacco extract or concentrated tobacco extract to form a nicotine composition.

[0135] The nicotine composition may be a liquid nicotine composition or a gel nicotine composition.

[0136] The nicotine composition may contain at least about 10 weight percent of liquid tobacco extract. Preferably, the nicotine composition contains at least about 20 weight percent of liquid tobacco extract. More preferably, the nicotine composition contains at least about 30 weight percent of liquid tobacco extract. In a preferred embodiment, the nicotine composition contains at least about 40 weight percent of liquid tobacco extract, more preferably at least about 50 weight percent of liquid tobacco extract, and even more preferably at least about 60 weight percent of liquid tobacco extract. In a particularly preferred embodiment, the nicotine composition contains at least about 65 weight percent of liquid tobacco extract, more preferably at least about 70 weight percent of liquid tobacco extract, even more preferably at least about 75 weight percent of liquid tobacco extract, and most preferably at least about 80 weight percent of liquid tobacco extract.

[0137] In some embodiments, the liquid tobacco extract is a concentrated tobacco extract. The nicotine composition may contain at least about 10 weight percent of concentrated tobacco extract, at least about 20 weight percent of concentrated tobacco extract, at least about 30 weight percent of concentrated tobacco extract, at least about 40 weight percent of concentrated tobacco extract, at least about 50 weight percent of concentrated tobacco extract, preferably at least about 60 weight percent of concentrated tobacco extract, more preferably at least about 70 weight percent of concentrated tobacco extract, even more preferably at least about 75 weight percent of concentrated tobacco extract, and most preferably at least about 80 weight percent of concentrated tobacco extract.

[0138] In some embodiments, the nicotine composition comprises about 40% to about 95% by weight of liquid tobacco extract. More preferably, the nicotine composition comprises about 40% to about 95% by weight of liquid tobacco extract. Even more preferably, the nicotine composition comprises about 50% to about 95% by weight of liquid tobacco extract. Most preferably, the nicotine composition comprises about 60% to about 95% by weight of liquid tobacco extract. In some particularly preferred embodiments, the nicotine composition comprises about 70% to about 95% by weight of liquid tobacco extract, and even more preferably, about 80% to about 95% by weight of liquid tobacco extract.

[0139] In some embodiments, the nicotine composition comprises about 40% to about 90% by weight of liquid tobacco extract. More preferably, the nicotine composition comprises about 40% to about 90% by weight of liquid tobacco extract. Even more preferably, the nicotine composition comprises about 50% to about 90% by weight of liquid tobacco extract. Most preferably, the nicotine composition comprises about 60% to about 90% by weight of liquid tobacco extract. In some particularly preferred embodiments, the nicotine composition comprises about 70% to about 90% by weight of liquid tobacco extract, and even more preferably, about 80% to about 90% by weight of liquid tobacco extract.

[0140] In some embodiments, the nicotine composition comprises about 40% to about 85% by weight of liquid tobacco extract. More preferably, the nicotine composition comprises about 40% to about 85% by weight of liquid tobacco extract. Even more preferably, the nicotine composition comprises about 85% to about 90% by weight of liquid tobacco extract. Most preferably, the nicotine composition comprises about 60% to about 85% by weight of liquid tobacco extract. In some particularly preferred embodiments, the nicotine composition comprises about 70% to about 85% by weight of liquid tobacco extract, and even more preferably about 80% to about 85% by weight of liquid tobacco extract.

[0141] The nicotine composition may contain up to about 100 weight percent of liquid tobacco extract. In some embodiments, the nicotine composition may be formed directly from the liquid tobacco extract without the need for additional non-aqueous solvents, flavorings, or nicotine additions. That is, the nicotine composition may contain 100 weight percent of liquid tobacco extract. In some embodiments, the liquid tobacco extract is a concentrated tobacco extract, and the nicotine composition may contain 100 weight percent of concentrated tobacco extract. In embodiments in which the nicotine composition contains 100 weight percent of liquid tobacco extract or 100 weight percent of concentrated tobacco extract, no additional non-aqueous solvents are present.

[0142] Alternatively, in some embodiments, the nicotine composition containing the liquid tobacco extract may contain an additional non-aqueous solvent. The additional non-aqueous solvent is a non-aqueous solvent added after the extraction step. The additional non-aqueous solvent is a solvent that supplements the non-aqueous extraction solvent present in the liquid tobacco extract. In embodiments where the liquid tobacco extract is a concentrated tobacco extract, the nicotine composition containing the concentrated tobacco extract may contain an additional non-aqueous solvent.

[0143] The additional non-aqueous solvent may be an aerosol-forming agent. Preferably, the additional non-aqueous solvent is triacetin, glycerin, propylene glycol, 1,3-propanediol, or a mixture thereof.

[0144] In embodiments in which the nicotine composition contains an additional non-aqueous solvent, the nicotine composition may contain 90% by weight or less of the additional non-aqueous solvent. Preferably, the nicotine composition contains 80% by weight or less of the additional non-aqueous solvent. More preferably, the nicotine composition contains 70% by weight or less of the additional non-aqueous solvent. In preferred embodiments, the nicotine composition contains about 60% by weight or less of the additional non-aqueous solvent, more preferably about 50% by weight or less of the additional non-aqueous solvent, and even more preferably about 40% by weight or less of the additional non-aqueous solvent. In particularly preferred embodiments, the nicotine composition contains about 35% by weight or less of the additional non-aqueous solvent, more preferably about 30% by weight or less of the additional non-aqueous solvent, even more preferably about 25% by weight or less of the additional non-aqueous solvent, and most preferably about 20% by weight or less of the liquid tobacco extract.

[0145] In a nicotine composition prepared by means of the method according to the present invention, at least 50 weight percent of the nicotine content in the nicotine composition, based on the total weight of the nicotine composition, can be obtained from a tobacco extract rather than being added after extraction. In a preferred embodiment, at least 80 weight percent of the nicotine content in the nicotine composition, based on the total weight of the nicotine composition, can be obtained from a tobacco extract rather than being added after extraction. More preferably, at least 90 weight percent of the nicotine content in the nicotine composition, based on the total weight of the nicotine composition, can be obtained from a tobacco extract rather than being added after extraction.

[0146] In a nicotine composition prepared by means of the method according to the present invention, at least 50% by weight of the non-aqueous extraction solvent content in the nicotine composition, based on the total weight of the nicotine composition, can be obtained from a tobacco extract rather than being added after extraction. In a preferred embodiment, at least 80% by weight of the non-aqueous extraction solvent content in the nicotine composition, based on the total weight of the nicotine composition, can be obtained from a tobacco extract rather than being added after extraction. More preferably, at least 90% by weight of the non-aqueous extraction solvent content in the nicotine composition, based on the total weight of the nicotine composition, can be obtained from a tobacco extract rather than being added after extraction.

[0147] In a nicotine composition prepared by means of the method according to the present invention, at least 50 weight percent of the water content in the nicotine composition, based on the total weight of the nicotine composition, can be obtained from a tobacco extract rather than being added after extraction. In a preferred embodiment, at least 80 weight percent of the water content in the nicotine composition, based on the total weight of the nicotine composition, can be obtained from a tobacco extract rather than being added after extraction. More preferably, at least 90 weight percent of the water content in the nicotine composition, based on the total weight of the nicotine composition, can be derived from a tobacco extract rather than being added after extraction.

[0148] In a nicotine composition prepared by means of the method according to the present invention, at least 50 weight percent of the desired tobacco flavor content in the nicotine composition, based on the total weight of the nicotine composition, can be obtained from a tobacco extract rather than being added after extraction. In a preferred embodiment, at least 80 weight percent of the desired flavor content in the nicotine composition, based on the total weight of the nicotine composition, can be obtained from a tobacco extract rather than being added after extraction. More preferably, at least 90 weight percent of the desired flavor content in the nicotine composition, based on the total weight of the nicotine composition, can be obtained from a tobacco extract rather than being added after extraction.

[0149] The total content of non-aqueous solvents in the nicotine composition includes the non-aqueous extraction solvent and, if present, additional non-aqueous solvents. The nicotine composition may contain a total non-aqueous solvent content of about 10% to about 95% by weight. Preferably, the nicotine composition contains a total non-aqueous solvent content of about 50% to about 95% by weight, for example, about 65% to about 95%, more preferably about 70% to about 90%, and most preferably about 80% to about 90%. The non-aqueous solvent is preferably triacetin, glycerin, propylene glycol, 1,3-propanediol, or a mixture thereof.

[0150] The nicotine composition may contain a total propylene glycol content of about 10% to about 95% by weight. The nicotine composition may contain a total propylene glycol content of about 20% to about 95% by weight, for example, about 50% to about 95% by weight, or about 65% to about 95% by weight, about 70% to about 90% by weight, or about 80% to about 90% by weight.

[0151] The nicotine composition may contain a total triacetin content of about 10% to about 95% by weight. The nicotine composition may contain a total triacetin content of about 20% to about 95% by weight, for example, about 50% to about 95% by weight, about 70% to about 90% by weight, or about 65% to about 95% by weight, or about 80% to about 90% by weight.

[0152] The nicotine composition may contain a total glycerin content of about 10% to about 95% by weight. The nicotine composition may contain a total glycerin content of about 20% to about 95% by weight, for example, about 50% to about 95% by weight, or about 65% to about 95% by weight, about 70% to about 90% by weight, or about 80% to about 90% by weight.

[0153] The nicotine composition may contain a total 1,3-propanediol content of about 10% to about 95% by weight. The nicotine composition may contain a total 1,3-propanediol content of about 20% to about 95% by weight, for example, about 50% to about 95% by weight, or about 65% to about 95% by weight, or about 80% to about 90% by weight.

[0154] The nicotine composition of the present invention contains at least 0.2 weight percent of nicotine. More preferably, the nicotine content in the nicotine composition liquid tobacco extract is at least about 0.4 weight percent. The nicotine composition may have a nicotine content of about 12 weight percent or less, for example, about 10 weight percent or less, preferably about 8 weight percent or less, more preferably about 5 weight percent or less, and preferably about 3.6 weight percent or less. Most preferably, the nicotine composition contains about 0.4 weight percent to 3.6 weight percent of nicotine based on the weight of the nicotine composition.

[0155] The nicotine composition may contain 1% to 85% by weight of water. The nicotine composition may contain 2% to 50% by weight of water. The nicotine composition may contain 3% to 30% by weight of water. The nicotine composition may contain 5% to 25% by weight of water. The nicotine composition may contain 8% to 20% by weight of water. The nicotine composition preferably contains 10% to 15% by weight of water.

[0156] In some embodiments, the nicotine composition may contain one or more water-soluble organic acids. As used herein in connection with the present invention, the term "water-soluble organic acid" refers to an organic acid having water solubility of about 500 mg / ml or more at 20°C.

[0157] One or more water-soluble organic acids can, advantageously, bind to nicotine in the liquid tobacco extract by forming one or more nicotine salts. These one or more nicotine salts can, advantageously, be dissolved and stabilized in water present in the liquid tobacco extract or in a non-aqueous solvent. This can, advantageously, reduce nicotine adsorption in the upper airways and enhance nicotine delivery and retention in the lungs, as discussed above.

[0158] Preferably, the water-soluble organic acid content of the nicotine composition is about 2% by weight or more. More preferably, the water-soluble organic acid content of the nicotine composition is about 3% by weight or more.

[0159] The water-soluble organic acid may be acetic acid.

[0160] Exogenous acetic acid is acetic acid added from a source other than tobacco plant material and is not naturally occurring acetic acid in tobacco plants that is separated, removed, or derived from tobacco plant material using extraction conditions and techniques.

[0161] When acetic acid is added to a liquid tobacco extract to form a nicotine composition, the total content of acetic acid in the nicotine composition, including both exogenous and endogenous acetic acid, is preferably about 0.01% to about 8% by weight, for example, about 0.03% to about 8%, about 0.3% to about 8%, about 2% to about 8%, or about 3% to about 8%. More preferably, the total content of acetic acid is about 0.01% to about 6% by weight, for example, about 0.03% to about 6%, about 0.3% to about 6%, about 2% to about 6%, or about 3% to about 6%.

[0162] Preferably, the water-soluble organic acid content of the nicotine composition is about 8% by weight or less. More preferably, the water-soluble organic acid content of the nicotine composition is about 6% by weight or less.

[0163] Preferably, the water-soluble organic acid content of the nicotine composition is about 2% to about 8% by weight. For example, the water-soluble organic acid content of the nicotine composition may be about 2% to about 6% by weight.

[0164] More preferably, the water-soluble organic acid content of the nicotine composition is about 3% to about 8% by weight. For example, the water-soluble organic acid content of the nicotine composition may be about 3% to about 6% by weight.

[0165] The nicotine composition may contain one or more non-tobacco flavoring agents. A suitable non-tobacco flavoring agent is, but is not limited to, menthol.

[0166] Preferably, the nicotine composition contains about 4% by weight or less of non-tobacco-derived flavoring agents. More preferably, the nicotine composition contains about 3% by weight or less of non-tobacco-derived flavoring agents. For example, using the liquid tobacco extract produced by the method of the present invention, a nicotine composition containing 10 to 20 mg of nicotine per milliliter can be prepared without the need for nicotine addition.

[0167] A nicotine composition suitable for use in an aerosol generating system may include a liquid tobacco extract produced by the method according to the present invention, in combination with water and an additional aerosol-forming agent. The nicotine composition may, for example, contain about 10% to about 20% by weight of water.

[0168] The nicotine composition containing the liquid tobacco extract according to the present invention may be provided in a cartridge for use in an aerosol generating system. The cartridge may comprise an atomizer configured to generate an aerosol from the nicotine composition. The atomizer may be a thermal atomizer configured to heat the nicotine composition to generate an aerosol. The thermal atomizer may comprise, for example, a heater and a liquid transport element configured to move the nicotine composition to the heater. The liquid transport element may include a capillary wick. Alternatively, the atomizer may be a non-thermal atomizer configured to generate an aerosol from the nicotine composition by means other than heating. The non-thermal atomizer may be, for example, an impingement jet atomizer, an ultrasonic atomizer, or a vibrating mesh atomizer.

[0169] A cartridge containing a nicotine composition formed from the liquid tobacco extract of the present invention may be used in conjunction with any suitable aerosol generating device, which includes a housing configured to receive at least a portion of the cartridge. The aerosol generating device may include a battery and control electronics.

[0170] One embodiment of the present invention will be explained further here, although only as an example.

[0171] Comparative Example In the method according to the present invention, tobacco material is cut to form tobacco fragments having dimensions of 2.5 mm × 2.5 mm, and the tobacco fragments are loaded into an extraction chamber without compression. The tobacco material is heated to a temperature of 140 degrees Celsius in the extraction chamber for 120 minutes. During heating, a flow of nitrogen passes through the extraction chamber at a flow rate of approximately 20 liters / minute. The tobacco flow rate is 30 kg per hour, and the extraction chamber is rotated at a speed of 1 rpm to circulate the tobacco.

[0172] During the heating process, atomized water was continuously sprayed into the extraction chamber at a pressure of 1 bar and a temperature of 22 degrees Celsius, at a rate of approximately 0.5 grams per second.

[0173] The volatile compounds released from the tobacco material during the heating process were collected by condensation at 0 degrees Celsius and dissolved in polypropylene glycol.

[0174] Nicotine composition 1 shown in the table below is a liquid tobacco extract obtained directly from the extraction process according to the present invention, and comprises a water spraying step.

[0175] In the second comparative extraction method, the tobacco material was extracted under the same conditions as above, except that the moisture content was maintained at approximately 10% ov (oven volatile matter) and the water spraying step was omitted. Therefore, the second extraction method is not in accordance with the present invention. Nicotine composition 2 shown in the table below is a liquid tobacco extract obtained directly from this second extraction method.

[0176] In the third comparative extraction method, the tobacco material was extracted under the same conditions as above, except that the tobacco material was humidified to a moisture content of 20% ov (oven volatile matter) before the heating step, and the water spray step was omitted. Therefore, the third extraction method is not according to the present invention. Nicotine composition 3 shown in the table below is a liquid tobacco extract obtained directly from this third extraction method.

[0177] Each nicotine composition was analyzed to measure its nicotine content, and the nicotine yield was calculated based on the total dry weight of the tobacco material. The extraction yield of specific flavor compounds was also measured. The results are shown in the table below. [Table 1]

[0178] As clearly shown in the table above, when the method according to the present invention includes a water spraying step, a significant increase in nicotine extraction yield is obtained compared to the method in which the water spraying step is omitted. A comparison of nicotine yields for nicotine compositions 1 and 3 also demonstrates that the improvement in nicotine yield is particularly provided by the atomized water spraying, as no increase in nicotine yield is observed when the tobacco material is moistened before heating, similar to the third comparative method described above. As also shown in the table above, including the water spraying step results in a significant improvement in the extraction yield of specific flavor compounds, including sotolon 68%, 2-phenylethanol 16%, 3-methylbutanoic acid 15%, and 2-methylbutanoic acid 3%.

Claims

1. A method for producing liquid tobacco extract, wherein the method is The process of preparing tobacco materials, The process involves heating the tobacco material in an extraction chamber at an extraction temperature of 120 to 160 degrees Celsius for at least 90 minutes. A step of collecting volatile compounds released from the tobacco material during the heating step, and The process includes forming a liquid tobacco extract containing the collected volatile compounds, The method further comprises a step of spraying atomized water into the extraction chamber during the heating step.

2. The method according to claim 1, wherein the atomized water spray generates a turbulent gas flow in the extraction chamber.

3. The method according to claim 1 or 2, wherein atomized water is continuously sprayed into the extraction chamber during the heating step.

4. The method according to any one of claims 1 to 3, wherein the atomized water is sprayed into the extraction chamber at a rate of at least 0.2 grams / second.

5. The method according to any one of claims 1 to 4, wherein the average flow rate of the water sprayed into the extraction chamber during the heating step is 3 percent to 30 percent of the flow rate of the tobacco material passing through the extraction chamber.

6. The method according to any one of claims 1 to 5, wherein the atomized water is atomized in a stream of compressed inert gas.

7. The method according to any one of claims 1 to 6, wherein the atomized water is sprayed into the extraction chamber at a pressure of at least 1 bar.

8. The method according to any one of claims 1 to 7, wherein the tobacco material is continuously circulated in the extraction chamber during the heating step.

9. The method according to any one of claims 1 to 8, wherein the amount of nicotine extracted from the tobacco material during the heating step corresponds to at least 2 grams per kilogram of dried tobacco material.

10. The method according to any one of claims 1 to 9, wherein the tobacco material is heated in a flow of inert gas during the heating step.

11. The method according to any one of claims 1 to 10, wherein the tobacco material is heated at an extraction temperature of 130 degrees Celsius to 150 degrees Celsius.

12. The method according to any one of claims 1 to 11, further comprising the step of subjecting the tobacco material to alkaline treatment before the heating step.

13. The method according to any one of claims 1 to 12, wherein the tobacco material is microwave-heated during at least one step of the method.

14. The method according to any one of claims 1 to 13, further comprising the step of drying or concentrating the collected volatile compounds.

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