Improved method for producing liquid tobacco extract

Abstract

This invention provides a method for producing a novel and improved liquid tobacco extract. [Solution] A method for producing liquid tobacco extract includes the steps of: preparing tobacco starting material; heating the tobacco starting material at an extraction temperature of 125°C to 160°C for 90 to 270 minutes; collecting volatile compounds released from the tobacco starting material during the heating process; and forming a liquid tobacco extract containing the collected volatile compounds.

Description

[Technical Field]

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

[0002] Aerosol generating systems for delivering aerosols to a user are known, comprising an atomizer configured to generate an inhalable aerosol from a liquid formulation, such as a liquid nicotine formulation. Some known aerosol generating systems comprise 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 generating system is the e-cigarette. Other known aerosol generating systems comprise a non-thermal atomizer configured to generate an aerosol from a liquid formulation, for example, using impingement jet, ultrasonic, or vibrating mesh technology.

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

[0004] In maceration, the tobacco material is held in a suspension in an extract for 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," there is generally no way to control the extraction conditions (e.g., temperature and pressure). For example, in the maceration variant described in U.S. Patent No. 2012 / 192880, the slurry is heated to over 100 degrees Celsius.

[0005] The liquid phase collected during slurry filtration is 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 optionally be 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] In alternative extraction processes, tobacco material is brought into contact 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, and the dissolved components of the feed material can be separated 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 have low levels of nicotine. Furthermore, liquid tobacco extracts obtained by these extraction processes may have low levels and limited variety of flavor species. Liquid tobacco extracts obtained by these extraction processes may also have high levels of undesirable compounds. Generally, the concentrations of nicotine, flavor species, and undesirable compounds obtained by such extraction processes may be significantly influenced by one or more types of tobacco used as starting material.

[0013] The object of the present invention is to mitigate one or more drawbacks of liquid tobacco extracts obtained by known processes. It is particularly desirable that such novel and improved liquid tobacco extracts be produced using existing equipment and techniques without requiring significant modifications. [Overview of the Initiative]

[0014] This disclosure relates to a method for producing a liquid tobacco extract from tobacco starting material. The method may include a step of preparing tobacco starting material. The tobacco starting material may be heated to an extraction temperature of about 100°C 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 starting material during the heating step. The method may further include a step of forming a liquid tobacco extract containing the collected volatile compounds.

[0015] The present invention provides a method for producing a liquid tobacco extract, the method comprising the steps of: preparing a tobacco starting material; heating the tobacco starting material at an extraction temperature of approximately 100 degrees Celsius to approximately 160 degrees Celsius for at least approximately 90 minutes; collecting volatile compounds released from the tobacco starting material during the heating step; and forming a liquid tobacco extract containing the collected volatile compounds.

[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" represents the direct product of an extraction process performed on a tobacco starting material. Thus, a tobacco extract typically comprises a mixture of natural components separated, removed, or derived from natural tobacco material using tobacco extraction processing conditions and techniques. Thus, in one such process, the extracted tobacco components are removed from the natural tobacco material and separated from the unextracted tobacco components. According to the present invention, an extraction process for producing a liquid tobacco extract comprises heating a tobacco starting material under specific heating conditions and collecting the volatile compounds produced. Thus, a liquid tobacco extract consists of a mixture of natural tobacco components derived from the tobacco starting material and extracted or formed during the extraction process, and typically is combined with one or more materials other than the tobacco starting material, such as a non-aqueous extraction solvent used during the extraction process. As will be described in more detail below, the volatile compounds released from the starting tobacco material can be collected using an absorption technique in which the volatile compounds are trapped in a 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 former.

[0018] The extraction method of the present invention advantageously provides an improved liquid tobacco extract in which the balance between desirable and undesirable compounds is significantly improved by using an extraction temperature within a specific range in combination with a particularly defined heating time. 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 the tobacco starting material is maximized. For example, by using a specific combination of defined extraction temperature and time, it is possible to optimize the level of nicotine compounds while at the same time minimizing the levels of undesirable compounds such as furan, carbonyl, phenol, and TSNA.

[0019] In contrast to the above-described existing extraction processes, the inventors of the present invention have found that the method according to the present invention advantageously provides a liquid tobacco extract having a significantly high content of compounds related to the flavor of heated tobacco, such as frangol. These compounds are substantially absent or present in trace amounts in tobacco extracts obtained by the maceration process and typically contain little or 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 typically have a very low content of such compounds related to the flavor of heated tobacco, if any.

[0020] The liquid tobacco extract obtained by the method according to the present invention exhibits a significant compositional difference compared to tobacco extracts obtained by existing extraction processes and can be used as an e-liquid or, upon heating, for the preparation of an e-liquid that generates an aerosol having a composition and flavor profile different from currently available e-liquids. In particular, the liquid tobacco extract obtained by the method according to the present invention can be used to generate an aerosol that provides a heated tobacco taste more similar to that of an aerosol generated by conventional tobacco or an aerosol generated when heating tobacco in a heat-not-burn device, compared to an available aerosol generated from an existing liquid nicotine composition.

[0021] The extraction method of the present invention enables the production of a liquid tobacco extract having the desired levels of nicotine and flavor compounds without adding such compounds after extraction. Thus, the obtained 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 e-cigarette or other aerosol-generating system.

[0022] As described above, an aerosol generating system for delivering an aerosol to a user is known, which includes an atomizer configured to generate an inhalable aerosol from a liquid formulation such as a liquid nicotine composition.

[0023] The method for producing liquid tobacco extract according to the present invention can be effectively used with all types and grades of tobacco, including Burley tobacco, roasted dry tobacco, and Oriental tobacco. The steps of this method can be easily adjusted to provide a consistent liquid tobacco extract for various blends of tobacco types. The extraction method is also suitable for various forms of tobacco starting materials.

[0024] In many cases, tobacco starting materials can be heated without requiring significant pretreatment steps. Therefore, this method can be implemented efficiently.

[0025] This method can be advantageously carried out using existing apparatus and techniques that can be easily modified to perform the steps of the present invention.

[0026] As defined above, the method for producing liquid tobacco extract involves heating tobacco starting material under specific heating conditions to release volatile tobacco components, which are then collected and formed into a liquid tobacco extract.

[0027] During the heating process, the tobacco starting material is heated to an extraction temperature of approximately 100°C to 160°C. Below this range, insufficient levels of nicotine and certain flavor compounds are released from the tobacco starting material, resulting in a liquid tobacco extract lacking the desired flavor characteristics. Conversely, if the tobacco starting material is heated above this defined range, unacceptably high levels of certain undesirable tobacco compounds may be released.

[0028] The extraction temperature is preferably at least about 110 degrees Celsius, more preferably at least about 115 degrees Celsius, more preferably at least about 120 degrees Celsius, and more preferably at least 125 degrees Celsius.

[0029] The extraction temperature is preferably about 150 degrees Celsius or lower, more preferably about 145 degrees Celsius or lower, even more preferably about 140 degrees Celsius or lower, and most preferably about 135 degrees Celsius or lower.

[0030] For example, the extraction temperature may be approximately 110°C to 150°C, or approximately 120°C to 140°C, or approximately 125°C to 135°C, or approximately 130°C. An extraction temperature of approximately 130°C has been found to yield a particularly optimized ratio of desirable to undesirable compounds in the liquid tobacco extract.

[0031] The extraction temperature may be approximately 110°C to 130°C, or approximately 115°C to 125°C, or approximately 120°C.

[0032] The extraction temperature may be approximately 125°C to 155°C, more preferably 135°C to 145°C, or 140°C.

[0033] The tobacco starting material is heated at the extraction temperature for at least about 30 minutes, or at least 60 minutes, or at least about 90 minutes, 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 with the desired flavor characteristics.

[0034] 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.

[0035] For example, the tobacco starting material may be heated for approximately 90 to 270 minutes, or approximately 120 to 180 minutes.

[0036] The heating time mentioned above corresponds to the time it takes for the tobacco starting material to be heated to the extraction temperature, and does not include the time it takes to raise the temperature of the tobacco starting material to the extraction temperature.

[0037] 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 starting 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.

[0038] 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 starting material. For example, it has been shown that the level of nicotine released from tobacco starting material typically increases with increasing extraction temperature. The rate of increase has been found to vary depending on the type of tobacco.

[0039] Furthermore, it was found that the levels of desirable tobacco flavor compounds, such as β-damascenone and β-ionone, released from the tobacco material increased as the extraction temperature rose to a specific peak extraction temperature, after which the levels began to decrease. The peak extraction temperature for such flavor compounds is typically in the range of 100°C to 160°C, so that the extraction method of the present invention can effectively optimize the levels of desirable flavor compounds.

[0040] 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 100°C to 160°C, and therefore, the levels of undesirable compounds can be effectively controlled in the extraction method of the present invention.

[0041] 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.

[0042] 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. More preferably, the extraction temperature, or the extraction time, or both, is selected to provide a weight ratio of at least about 0.5, even more preferably at least 1, and most preferably at least about 1.5 (β-ionone + β-damascenone) to (phenol) in the liquid tobacco extract. In a particularly preferred embodiment, the extraction temperature, or the extraction time, or both, is selected so that the weight ratio of (β-ionone + β-damascenone) to (phenol) in the liquid tobacco extract is at least about 2, most preferably about 2 to about 10 or about 2 to about 5.

[0043] β - Damascenone and β - Ionone are desirable compounds related to tobacco flavor. It has also been found that the amounts of β - Damascenone and β - Ionone released from tobacco materials increase as the extraction temperature rises to a specific peak extraction temperature and then begin to decrease in level. The peak extraction temperature of such flavor compounds is typically within the range of 100°C to 160°C so that the level of desirable flavor compounds can be effectively adjusted and controlled by the extraction method.

[0044] Preferably, the extraction temperature, or the extraction time, or both the extraction temperature and the extraction time are selected to provide at least about 5x10 -4 of the weight ratio of (furaneol + (2,3 - diethyl - 5 - methylpyrazine) * 100)) to (nicotine) in the liquid tobacco extract. More preferably, the extraction temperature, or the extraction time, or both the extraction temperature and the extraction time are selected to provide at least about 8x10 -4 , even more preferably at least 1x10 -3 of the weight ratio of (furaneol + (2,3 - diethyl - 5 - methylpyrazine) * 100)) to (nicotine) in the liquid tobacco extract. The extraction temperature, or the extraction time, or both the extraction temperature and the extraction time are preferably selected to provide a weight ratio of (furaneol + (2,3 - diethyl - 5 - methylpyrazine) * 100)) to (nicotine) in the liquid tobacco extract of about 9x10 -3 or less, more preferably 5x10 -3 or less. In some preferred embodiments, the extraction temperature, or the extraction time, or both the extraction temperature and the extraction time are about 8x10 -4 to about 9x10 -3 , or about 8x10 -4 to about 5x10 -3 , or about 1x10 -3 to about 9x10 -3 , or about 1x10 -3 to about 5x10 -3 of the weight ratio of (furaneol + (2,3 - diethyl - 5 - methylpyrazine) * 100)) to (nicotine) in the liquid tobacco extract.

[0045] 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.

[0046] 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 starting 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.

[0047] Volatile tobacco compounds are released into an inert gas flow during the heating process so that the inert gas (or a combination of inert gas and water or vapor) acts as a carrier for the volatile components. The inert gas flow rate may be optimized based on the scale and shape of the extraction chamber. Relatively high flow rates of the inert gas can favorably improve the efficiency of extraction from the tobacco starting material.

[0048] Generally, when tobacco starting material is heated, any moisture present in the tobacco starting material is also released along with volatile compounds in the form of vapor.

[0049] The flow of inert gas helps to remove vapors produced by the evaporation of moisture content from the tobacco starting material, and volatile compounds, particularly nicotine or flavor-related compounds, or both, from the extraction device.

[0050] Furthermore, using a flow of an inert gas such as nitrogen under slight overpressure within the extraction apparatus has the advantage of preventing the presence of oxygen within the apparatus. This is desirable in that it prevents the risk of the tobacco starting material burning, even partially, during the heating process. Uncontrolled combustion of tobacco starting material is obviously undesirable as it poses a significant safety risk in the manufacturing environment. However, the inventors have found that even limited and partial combustion of tobacco starting material can lead to a deterioration in the quality of the tobacco extract obtainable by this method, which is undesirable.

[0051] While not intended to be constrained by theory, it is understood that preventing the combustion of tobacco starting materials also prevents the formation of undesirable combustion byproducts. Furthermore, because conditions that promote the combustion of tobacco starting materials are prevented, the tobacco starting materials are effectively heated under conditions that, to some extent, mimic the conditions under which tobacco-containing substrates (e.g., homogenized tobacco materials) are typically heated in "heat-non-combustible" articles. As a result, it is advantageously supported that consumers selectively extract volatile species that contribute to the flavor associated with heated tobacco products.

[0052] Therefore, performing the heating process in an inert atmosphere advantageously enhances extraction efficiency, product quality, and manufacturing safety.

[0053] Heating tobacco starting material in an inert gas flow has the additional benefit that the inert gas flow containing volatile compounds can be more easily directed towards a container containing an extraction solvent, such as a non-aqueous extraction liquid solvent.

[0054] 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 starting material or volatile compounds produced during heating of the tobacco starting material with oxygen. The removal of oxygen also prevents any combustion of the tobacco starting material, as described above.

[0055] Suitable heating methods for heating tobacco starting 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.

[0056] Liquid tobacco extracts can be produced from tobacco starting materials consisting of a single type of natural tobacco. Alternatively, the tobacco starting materials may include 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 may be increased.

[0057] In this specification, the term “natural tobacco” is used in connection with the present invention to describe any part of any plant member of the genus Nicotiana, including, but not limited to, leaves, midribs, stems, and petioles. 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.

[0058] 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.

[0059] The tobacco starting material may be a solid tobacco material such as powder, leaf scraps or fragments, or intact leaves. Alternatively, the tobacco starting material may be a liquid tobacco material such as dough, gel, slurry, or suspension.

[0060] Tobacco starting materials may be derived from any suitable tobacco material, including but not limited to tobacco leaves, tobacco stems, recombined tobacco, cast tobacco, extruded tobacco, or tobacco-derived pellets.

[0061] In the process of preparing tobacco starting material, it is preferable that the tobacco be crushed or cut in order to reduce the size of the tobacco particles in the tobacco starting material. This can advantageously improve the homogeneity of heating and the efficiency of extraction of the tobacco starting material.

[0062] The tobacco starting material may optionally be dried before the heating step to reduce its moisture content. Drying of the tobacco starting material may be carried out by any suitable chemical or physical drying process. Alternatively, water may be added to the tobacco starting material before the heating step to increase its moisture content.

[0063] In certain embodiments of the present invention, the step of preparing a tobacco starting material may include the step of impregnating the tobacco starting material with an aerosol-forming agent. If this impregnation of the tobacco starting material is carried out before the heating step, it is advantageous that the amount of certain desirable tobacco compounds released from the tobacco starting material during heating can be increased. For example, impregnation of the tobacco starting material with glycerin has been found to advantageously increase the amount of nicotine extracted from the tobacco starting material. In another embodiment, impregnation of the tobacco starting 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 starting material.

[0064] In a preferred embodiment, the tobacco starting material consists of natural tobacco. Thus, the moisture content of the tobacco starting material may be about 11 weight percent (the moisture content typically found in natural tobacco material).

[0065] In other embodiments, the tobacco starting material may include one or more additional components, such as a non-aqueous solvent, added water, or both. Examples of suitable solvents include propylene glycol.

[0066] Therefore, the tobacco starting 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] Optionally, the tobacco starting material may be enzymatically digested before the heating step. This has been found to result in a significant increase in the yield of certain flavor compounds from the tobacco starting material.

[0072] In the process of preparing tobacco starting materials, it is preferable that the tobacco is not subjected to any treatment that would alter its pH. In particular, in the process of preparing tobacco starting materials, the tobacco is not subjected to any treatment that would significantly increase its pH. For example, the tobacco starting materials are not brought into contact with aqueous solutions containing alkali or alkaline earth metal salts. Advantageously, it has been found that maintaining the tobacco material in a less modified state can provide a more authentic or more natural flavor profile that can be appreciated by consumers. Furthermore, it has been shown that the absence of any treatment that would alter the pH of the tobacco starting materials results in a liquid tobacco extract having a particularly optimized ratio of desirable to undesirable compounds.

[0073] The tobacco starting 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.

[0074] During heating of tobacco starting material, volatile compounds are released from the tobacco starting material in gaseous form. These volatile compounds are collected using any suitable technique. If, as described above, the tobacco starting material is heated in a flow of inert gas, the volatile compounds are collected from the flow of inert gas. Different collection methods will be well known to those skilled in the art.

[0075] 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.

[0076] 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).

[0077] 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.

[0078] 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. The resulting condensate is preferably added to a liquid aerosol former, preferably propylene glycol.

[0079] 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 apparatus, 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, while these compounds may unnecessarily accumulate on the surface of the apparatus.

[0080] Furthermore, liquid aerosol forms, regardless of their polarity and volatility, are advantageous in capturing flavor-related compounds. Moreover, during any subsequent drying process, liquid aerosol forms help prevent the loss of the most volatile fractions and are advantageous in selectively removing excess water from naturally derived liquid tobacco extracts to obtain concentrated tobacco extracts.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] In preferred embodiments, the weight ratio of (β-ionone + β-damascenone) to (phenol) in the liquid tobacco extract is at least about 0.25. More preferably, the weight ratio of (β-ionone + β-damascenone) to (phenol) in the liquid tobacco extract is at least about 0.5, even more preferably at least about 1, and most preferably at least about 1.5. In particularly preferred embodiments, the weight ratio of (β-ionone + β-damascenone) to (phenol) in the liquid tobacco extract is at least about 2, most preferably about 2 to about 10, or about 2 to about 5.

[0090] 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 More preferably, the weight ratio of (furaneol + (2,3-diethyl-5-methylpyrazine)*100) to (nicotine) in the liquid tobacco extract is at least about 8 x 10 -4 More preferably, the weight ratio of (furaneol + (2,3-diethyl-5-methylpyrazine)*100) to (nicotine) in the liquid tobacco extract is at least about 1 x 10⁻¹⁰ -3 That is the case.

[0091] Preferably, the weight ratio of (furaneol + (2,3-diethyl-5-methylpyrazine)*100) to (nicotine) in the liquid tobacco extract is approximately 9 x 10 -3 The following is more preferable: The weight ratio of (furaneol + (2,3-diethyl-5-methylpyrazine)*100) to (nicotine) in the liquid tobacco extract is approximately 5 x 10 -3 The following applies:

[0092] In some preferred embodiments, the weight ratio of (furaneol + (2,3-diethyl-5-methylpyrazine)*100) to (nicotine) in the liquid tobacco extract is approximately 8 x 10 -4 ~approximately 9x10 -3 , or approximately 8x10 -4 ~about 5x10 -3 , or approximately 1x10 -3~approximately 9x10 -3 , or approximately 1x10 -3 ~about 5x10 -3 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.

[0093] In a preferred embodiment, the solution of the volatile compound in the liquid solvent is concentrated by drying.

[0094] 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 the liquid solvent may be heated for a certain period of time to a temperature such that the water content in the tobacco extract is reduced by at least about 60 percent.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] The process of forming a liquid tobacco extract may optionally include a filtration step.

[0099] Optionally, the process of forming a liquid tobacco extract may include a blending process in which extracts derived from different tobacco starting materials are combined.

[0100] 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.

[0101] 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.

[0102] 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 generator.

[0103] 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 in through the aerosol generator. As the released compounds cool, they condense to form an aerosol, which is inhaled by the consumer.

[0104] 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 starting 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] Preferably, the concentrated tobacco extract contains 8% to 15% by weight of water, based on the weight of the concentrated tobacco extract.

[0109] 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.

[0110] 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.

[0111] Preferably, an additional non-aqueous solvent may be added to the liquid tobacco extract or concentrated tobacco extract to form a nicotine composition.

[0112] The nicotine composition may be a liquid nicotine composition or a gel nicotine composition.

[0113] 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. Most 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] The additional non-aqueous solvent may be an aerosol-forming agent. The additional non-aqueous solvent is preferably triacetin, glycerin, propylene glycol, 1,3-propanediol, or a mixture thereof.

[0121] In embodiments in which the nicotine composition contains an additional non-aqueous solvent, the nicotine composition may contain 90 weight percent or less of the additional non-aqueous solvent. Preferably, the nicotine composition contains 80 weight percent or less of the additional non-aqueous solvent. More preferably, the nicotine composition contains 70 weight percent or less of the additional non-aqueous solvent. In preferred embodiments, the nicotine composition contains about 60 weight percent or less of the additional non-aqueous solvent, more preferably about 50 weight percent or less of the additional non-aqueous solvent, and even more preferably about 40 weight percent or less of the additional non-aqueous solvent. In particularly preferred embodiments, the nicotine composition contains about 35 weight percent or less of the additional non-aqueous solvent, more preferably about 30 weight percent or less of the additional non-aqueous solvent, even more preferably about 25 weight percent or less of the additional non-aqueous solvent, and most preferably about 20 weight percent or less of the liquid tobacco extract.

[0122] 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.

[0123] 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.

[0124] In a nicotine composition prepared by means of the method according to the present invention, at least 50% by weight 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% by weight 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% by weight 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.

[0125] 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.

[0126] For example, in a nicotine composition prepared by means of the method according to the present invention, at least 50% by weight of the furaneol 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 furaneol 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 furaneol 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.

[0127] As another example, in a nicotine composition prepared by means of the method according to the present invention, at least 50 weight percent of the 2,3-diethyl-5-methylpyrazine 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 2,3-diethyl-5-methylpyrazine 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 2,3-diethyl-5-methylpyrazine 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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. Preferably, the nicotine composition contains 10% to 15% by weight of water.

[0135] 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.

[0136] 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 described above.

[0137] The water-soluble organic acid content of the nicotine composition is preferably 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.

[0138] The water-soluble organic acid may be acetic acid.

[0139] 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.

[0140] 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%.

[0141] The water-soluble organic acid content of the nicotine composition is preferably 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.

[0142] The water-soluble organic acid content of the nicotine composition is preferably 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.

[0143] The water-soluble organic acid content of the nicotine composition is more preferably 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.

[0144] 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.

[0145] The nicotine composition preferably 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.

[0146] 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.

[0147] The nicotine composition comprising a 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 produce an aerosol. The thermal atomizer may comprise, for example, a heater and a liquid transport element configured to transport the nicotine composition to the heater. The liquid transport element may comprise a capillary core. 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.

[0148] 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 generator having a housing configured to receive at least a portion of the cartridge. The aerosol generator may include a battery and control electronics.

[0149] One embodiment of the present invention will be explained further here, although only as an example. [Examples]

[0150] Example 1 The tobacco starting material is prepared from fire-dried bright tobacco material. The tobacco material is cut to form tobacco strips with dimensions of 2.5 mm x 2.5 mm, and the tobacco strips are loaded into the extraction chamber without compression. The tobacco starting material is heated in the extraction chamber to a temperature of 130 degrees Celsius for 3 hours. During heating, a flow of nitrogen passes through the extraction chamber at a flow rate of approximately 40 liters / minute.

[0151] Volatile compounds released from the tobacco starting material during the heating process are collected by being absorbed into a liquid solvent formed from propylene glycol under stirring at 750 rpm at minus 10 degrees Celsius.

[0152] The nicotine composition of Example 1 is a liquid tobacco extract obtained directly from an extraction process at a temperature of 130 degrees Celsius for 3 hours. The nicotine composition provides optimized levels of desirable flavor compounds such as β-damascenone and β-ionone, against undesirable compounds such as phenol, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, (R,S)-N-nitrosoanatabine, (R,S)-N-nitrosoanabasine, N-nitrosonornicotine, and 2-furan methanol. The nicotine composition further provides a certain level of desirable flavor compounds, for example, furaneol and 2,3-diethyl-5-methylpyrazine, to nicotine.

[0153] The propylene glycol solution containing the collected volatile compounds is concentrated through a drying process to reduce the moisture level of the liquid tobacco extract to approximately 15 percent.

[0154] Example 2 This example provides two nicotine compositions according to this specification, both of which are liquid tobacco extracts obtained directly from an extraction process at a temperature of 130 degrees Celsius for 3 hours.

[0155] Example 2a Example 2a relates to a liquid tobacco extract derived from heat-dried bright tobacco material. The content of the concentrated liquid tobacco extract in Example 2a is as follows: Nicotine: 0.53% w / w • Propylene glycol: 91.8% w / w Water: 6.3% w / w • Balance (including flavorings detailed in Table 1 below): 1.57% w / w

[0156] Example 2b Example 2b relates to a liquid tobacco extract derived from Burley tobacco material. The content of the concentrated liquid tobacco extract in Example 2b is as follows: Nicotine: 1.82% w / w • Propylene glycol: 89.6% w / w Water: 5.7% w / w • Balance (including flavorings detailed in Table 1 below): 2.88% w / w [Table 1]

[0157] The nicotine compositions of Examples 2a and 2b according to the present invention contain undesirable compounds at acceptable levels, such as phenol, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, (R,S)-N-nitrosoanatabine, (R,S)-N-nitrosoanabasin, N-nitrosonornicotine, and 2-furan methanol.

[0158] Example 3 This example provides three nicotine compositions according to this specification, each of which is a liquid tobacco extract obtained directly from an extraction process at a temperature of 130 degrees Celsius for 3 hours.

[0159] Example 3a Example 3a relates to a liquid tobacco extract derived from Oriental Leaf Bright tobacco material. The content of the liquid tobacco extract in Example 3a is as follows: Nicotine: 0.4% w / w • Propylene glycol: 84% w / w • Acetic acid: 1.0% w / w Water: 12.5% ​​w / w • Balance (including flavorings): 2.1% w / w

[0160] Example 3b Example 3b relates to a liquid tobacco extract derived from heat-dried bright tobacco material. The content of the liquid tobacco extract in Example 3b is as follows: Nicotine: 1.2% w / w • Propylene glycol: 84% w / w • Acetic acid: 1.0% w / w Water: 12.5% ​​w / w • Balance (including flavorings): 1.3% w / w

[0161] Example 3c Example 3c relates to a liquid tobacco extract derived from Burley tobacco material. The content of the liquid tobacco extract in Example 3c is as follows: Nicotine: 2.6% w / w • Propylene glycol: 84% w / w • Acetic acid: 0.5% w / w Water: 12.5% ​​w / w • Balance (including flavorings): 0.4% w / w

[0162] The nicotine composition of Example 3 provides optimized levels of desirable flavor compounds such as β-damascenone and β-ionone, as opposed to undesirable compounds such as phenol, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, (R,S)-N-nitrosoanatabine, (R,S)-N-nitrosoanabasine, N-nitrosonornicotine, and 2-furan methanol. The nicotine composition further provides a certain level of desirable flavor compounds, for example, furaneol and 2,3-diethyl-5-methylpyrazine, to nicotine.

[0163] Example 4 The liquid tobacco extract from Example 1 was concentrated using a drying process to reduce the moisture level of the liquid tobacco extract to approximately 15 percent.

[0164] Glycerin was added to the resulting concentrated liquid tobacco extract to form a nicotine composition, which, based on the weight of the nicotine composition, contained 20% by weight glycerin and 80% by weight liquid tobacco extract.

[0165] Example 5 Example 4 relates to a nicotine composition in gel form according to the present invention. The gel nicotine composition is formed from the liquid tobacco extract of Example 1. The content of the gel nicotine composition is as follows: • Liquid tobacco extract in Example 1: 99.0% w / w Agar: 1.0% w / w

[0166] Example 6 Three tobacco starting materials are prepared from heat-dried bright tobacco material (6A), Burley tobacco material (6B), and Oriental tobacco material (6C), respectively.

[0167] Each of the three tobacco materials is cut to form tobacco strips having dimensions of 2.5 mm x 2.5 mm, and the tobacco strips are loaded into the extraction chamber without compression.

[0168] Each tobacco starting material is heated in the extraction chamber to a temperature of 130 degrees Celsius for 120 minutes. During heating, a stream of nitrogen passes through the extraction chamber at a flow rate of 2 liters / minute.

[0169] The volatile compounds released from each tobacco starting material during the heating process are collected by being absorbed into a liquid solvent formed from polypropylene glycol at 0 degrees Celsius.

[0170] Liquid tobacco extracts are obtained directly from these extraction processes. Each liquid extract obtained from each of the three tobacco starting materials is then concentrated under vacuum (50 mbar) at 55 degrees Celsius until a moisture content of 12 percent ± 2 percent is reached. [Table 2]

[0171] In all three liquid extracts according to Invention 6A, 6B, and 6C, the weight ratio of (β-ionone + β-damascenone) to (phenol) is consistently and significantly greater than 2.0. Furthermore, in all three liquid extracts according to Invention 6A, 6B, and 6C, the weight ratio of (furaneol + (2,3-diethyl-5-methylpyrazine)*100) to (nicotine) is consistently and significantly greater than 1 × 10⁻⁶. -3 Furthermore, in all three liquid extracts according to Invention 6A, 6B, and 6C, the weight ratio of (β-ionone + β-damascenone) to (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone + (R,S)-N-nitrosoanatabine + (R,S)-N-nitrosoanabasin + N-nitrosonornicotine + ((2-furan methanol) / 600)) is consistently and significantly greater than 3.

[0172] 1. A method for producing liquid tobacco extract, The process of preparing tobacco starting materials, The process involves heating the aforementioned tobacco starting material at an extraction temperature of 125°C to 160°C for 90 to 270 minutes, The process includes collecting volatile compounds released from the tobacco starting material during the heating process, A method comprising the step of forming a liquid tobacco extract containing the collected volatile compounds. 2. The method according to 1, wherein the tobacco starting material is heated to an extraction temperature of approximately 125 degrees Celsius to approximately 140 degrees Celsius. 3. The method according to 1 or 2, wherein the tobacco starting material is heated at the extraction temperature for at least 120 minutes. 4. The method according to any one of 1 to 3, wherein the extraction temperature is selected to provide a liquid tobacco extract having a nicotine content of at least 0.2 weight percent based on dry mass. 5. The method according to any one of 1 to 4, wherein the extraction temperature is selected to provide a weight ratio of at least about 0.25 for (β-ionone + β-damascenone) to (phenol). 6. The extraction temperature is at least about 5 × 10 -4 The method according to any one of 1 to 5, selected to provide a weight ratio of (furaneol + (2,3-diethyl-5-methylpyrazine)*100) to (nicotine). 7. The method according to any one of 1 to 6, wherein the tobacco starting material is heated with a flow of inert gas. 8. The method according to any one of 1 to 7, wherein the tobacco starting material is impregnated with an aerosol forming body before the heating step. 9. The method according to any one of 1 to 8, wherein the volatile compound is collected by condensation. 10. The method according to any one of 1 to 8, wherein the volatile compound is collected by absorption into a liquid carrier, preferably an aerosol-forming body. 11. The method according to 10, wherein the aerosol forming body comprises glycerin, propylene glycol, or a combination thereof. 12. The method according to any one of 1 to 11, further comprising the step of drying or concentrating the collected volatile compounds. 13. The method according to any one of 1 to 12, wherein the step of preparing the tobacco starting material includes grinding the tobacco material to form tobacco powder. 14. The method according to any one of 1 to 13, wherein in the step of preparing the tobacco starting material, the tobacco is not subjected to any treatment adapted to change the pH of the tobacco. 15. Liquid tobacco extract produced by any of the methods described in 1-14.

Claims

1. A method for producing liquid tobacco extract, A step of preparing tobacco starting material containing natural tobacco material, wherein the tobacco starting material is not subjected to any treatment adapted to change the pH of the tobacco starting material. The process involves heating the aforementioned tobacco starting material in a flow of inert gas at an extraction temperature of 125 to 160 degrees Celsius for 90 to 270 minutes, The process includes collecting volatile compounds released from the tobacco starting material during the heating process, A method comprising the step of forming a liquid tobacco extract containing the collected volatile compounds.

2. The method according to claim 1, wherein the tobacco starting material is heated at an extraction temperature of 125 degrees Celsius to 140 degrees Celsius.

3. The method according to claim 1 or 2, wherein the tobacco starting material is heated at the extraction temperature for at least 120 minutes.

4. The method according to any one of claims 1 to 3, wherein the extraction temperature is selected to provide a liquid tobacco extract having a nicotine content of at least 0.2 weight percent based on dry mass.

5. The method according to any one of claims 1 to 4, wherein the extraction temperature is selected to provide a weight ratio of at least 0.25 (β-ionone + β-damascenone) to (phenol).

6. The extraction temperature is at least 5 × 10 -4 The method according to any one of claims 1 to 5, selected to provide a weight ratio of (furaneol + (2,3-diethyl-5-methylpyrazine) * 100) to (nicotine).

7. The method according to any one of claims 1 to 6, wherein the tobacco starting material is impregnated with an aerosol forming body before the heating step.

8. The method according to any one of claims 1 to 7, wherein the volatile compound is collected by condensation.

9. The method according to any one of claims 1 to 7, wherein the volatile compound is collected by absorption into a liquid solvent containing an aerosol-forming body.

10. The method according to claim 9, wherein the aerosol-forming body comprises glycerin, propylene glycol, or a combination thereof.

11. The method according to any one of claims 1 to 10, further comprising the step of drying or concentrating the collected volatile compounds.

12. The method according to any one of claims 1 to 11, wherein the step of preparing the tobacco starting material includes crushing the tobacco starting material to form tobacco powder.

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