KR20230118138A - An Improved Method for Making Liquid Tobacco Extract - Google Patents

Abstract

A method of preparing a liquid tobacco extract comprises preparing a tobacco material; heating the tobacco material at an extraction temperature of 100°C to 160°C for at least 15 minutes; collecting volatile compounds released from the tobacco material during the heating step; and forming a liquid tobacco extract including the collected volatile compounds. Tobacco material is microwave heated during at least one step of the method.

Description

An Improved Method for Making Liquid Tobacco Extract

The present invention relates to a method for preparing a liquid tobacco extract and a liquid tobacco extract produced by the method.

Aerosol-generating systems for delivering an aerosol to a user are known that include a nebulizer configured to generate an inhalable aerosol from a liquid formulation, such as a liquid nicotine formulation. Some known aerosol-generating systems include thermal sprayers, such as electric heaters, that are configured to heat and evaporate a liquid formulation to generate an aerosol. One popular type of electrically heated aerosol-generating system is the electronic cigarette. Other known aerosol-generating systems include non-thermal atomizers configured to generate an aerosol from a liquid formulation using, for example, impinging jets, ultrasound, or vibrating mesh technology.

Several methods are known for producing liquid tobacco extracts from tobacco material. Liquid tobacco extract may be produced by a hot 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.

Leaching methods are also known, wherein the tobacco material is kept in suspension in the extraction liquid for a period of up to several weeks or even months. The resulting slurry is subsequently filtered, and the liquid phase thus collected can be used to prepare a vaporizable liquid formulation. In one such method - the so-called "cold leaching method" - there is generally no way to control the extraction conditions (eg temperature and pressure). In a variant of the leaching method described for example in US 2012/192880, the slurry is heated above 100 °C.

The liquid phase collected on filtration of the slurry, which represents the primary product of the leaching process, tends to be highly dilute and have a low content of non-polar tobacco flavored species. Also, liquids generally contain little or no nicotine. As such, liquid extracts obtained by the leaching method generally need to be supplemented with additional ingredients such as nicotine salts and glycerin before being used in vaporizable liquid formulations.

An alternative process is known, in which tobacco material is boiled substantially in water over a period of several hours or even days to form a gas phase, and the distillate obtained by condensation of the gas phase is continuously collected in a vessel. Over time, an oily, waxy layer containing a high proportion of non-polar compounds builds up on the surface of the distillate.

Meanwhile, the wax layer builds up and the aqueous portion containing nicotine and other water-soluble compounds is recycled to the boiler. A non-polar co-solvent may optionally be fed into the boiler along with the aqueous portion to increase the extraction yield. Meanwhile, the wax phase is collected and ultimately forms the primary product of one such hydro-distillation process. This product is often referred to as "tobacco essential oil" and contains a high proportion of non-polar compounds found in tobacco, such as fatty acids, neopitadiene, and the like. Tobacco essential oils obtained by one such method are usually nicotine-free.

It is also known to subject tobacco material to an extraction process involving the use of volatile apolar solvents. Examples of suitable solvents are cyclic or acyclic short alkanes, as well as chlorinated solvents such as dichloromethane. In one such process, excess solvent may 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 traces of the extraction solvent can be detected.

The primary product of one such solvent-assisted extraction process is often referred to as "tobacco absolute" and may contain traces of ethanol. It is a wax product and contains a highly concentrated mixture of mostly non-polar compounds, which are usually present in relatively high concentrations and can be extracted with certain solvents, usually containing nicotine.

An alternative extraction process involves contacting the tobacco material with a solvent under supercritical conditions, such as supercritical carbon dioxide. One such process is disclosed in US 2013/160777 and relies on the principle that volatile materials in a feed material contacted with a supercritical fluid can partition into a supercritical phase. After dissolution of any soluble material, the supercritical fluid containing the dissolved material may be removed and the dissolved component of the feed material may be separated from the supercritical fluid. The primary product of the supercritical extraction process is substantially similar to the "tobacco absolute" of the solvent-assisted extraction process run at lower temperatures and pressures, contains no residual solvents, and typically has high levels of waxes, non-polar compounds. , contains nicotine, which is generally present in relatively high concentrations.

However, all tobacco extracts obtainable by methods known in the art tend to have very low levels (if present) of compounds associated with the flavor of heated tobacco, such as furaneol.

Generally, as mentioned above, the liquid tobacco extract obtained by this known extraction process may have low levels of nicotine. Also, the liquid tobacco extract obtained by this extraction process may have low levels and low varieties of flavor species. The liquid tobacco extract obtained by this extraction process may also have high levels of undesirable compounds. In general, the concentrations of nicotine, flavor species and undesirable compounds obtained by this extraction process can be significantly influenced by the type or types of tobacco used as a starting material.

It is an object of the present invention to alleviate one or more of the disadvantages of liquid tobacco extracts obtained by known processes. In particular, it would be desirable to provide a new and improved method for preparing a liquid tobacco extract. It would be particularly desirable to provide such a process for preparing such a liquid tobacco extract that can be performed more efficiently than existing processes.

The present disclosure relates to a method for preparing a liquid tobacco extract from tobacco material. The method may include preparing a tobacco material. Tobacco material may be heated at an extraction temperature of about 100°C to about 160°C. Heating may be performed for at least 15 minutes. The method may further include collecting volatile compounds released from the tobacco material during the heating step. The method may further include forming a liquid tobacco extract comprising the collected volatile compounds. Tobacco material may be microwave heated during at least one step of the method.

According to the present invention, there is provided a method for preparing a liquid tobacco extract, the method comprising preparing a tobacco material; collecting the volatile compounds released from the tobacco material at an extraction temperature of about 100° C. to about 160° C. for at least about 15 minutes; and forming a liquid tobacco extract including the collected volatile compounds. According to the invention, the tobacco material is microwave heated during at least one step of the method.

According to the present invention, there is further provided a liquid tobacco extract prepared by the method of the present invention, as defined above.

As used herein with reference to the present invention, the term “liquid tobacco extract” describes the direct product of an extraction process performed on tobacco material. Thus, tobacco extract generally comprises a mixture of natural components that have been 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 includes heating tobacco material under specific heating conditions and collecting the resulting volatile compounds. Volatile compounds will be in gaseous form when released from the tobacco material. 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 in combination with one or more substances other than tobacco material, such as non-aqueous extraction solvents used during the extraction process. do. As described in more detail below, volatile compounds released from the starting tobacco material may be collected using absorption techniques in which the volatile compounds are entrapped in a non-aqueous extraction solvent. As an example, an inert gas stream containing volatile compounds may be directed into a vessel of non-aqueous extraction solvent. The non-aqueous extraction solvent is preferably an aerosol former.

The present invention relates to a novel microwave assisted extraction method comprising microwave heating of tobacco material at some stage during the extraction method. As explained in more detail below, the tobacco material may be microwave heated prior to the heating step in which the tobacco material is heated to a temperature between 100°C and 160°C, or microwave heating may occur during the heating step.

The inclusion of a microwave heating step in the extraction method of the present invention has been found to significantly increase the nicotine extraction yield, in some cases by up to 600%, compared to an equivalent extraction method without the microwave heating step. This effect is believed to be due to the way the microwaves heat the tobacco from the inside by rapidly heating the water molecules within the tobacco cells. When the water inside the tobacco cells boils, the volume inside the cells expands rapidly and the cell walls eventually rupture. This increases the permeability of the plant material and, importantly, releases components contained within the cell wall, such as nicotine. Then, these components are more available to be extracted during the heating step so that the yield of these components is increased.

Microwave heating typically provides a higher depth of penetration and faster heating of the tobacco material than conventional resistance heating methods, which may advantageously reduce the time required to perform the extraction process. For example, the inclusion of a microwave heating step has been found by the inventors to result in a reduction of up to 80% in the duration of the heating step. In addition, a reduction in energy use of up to 40% may be provided. Thus, the inclusion of a microwave heating step allows the extraction process as a whole to be performed very efficiently both in terms of energy and time.

As mentioned above, due to the manner in which microwaves heat the tobacco material from inside the tobacco cells, more uniform heating of the tobacco material can also be achieved compared to conventional heating methods, such as resistance heating, which can heat the tobacco material from the outside. can

Microwave heating of tobacco material can be performed using a relatively simple and inexpensive device that can be easily integrated into existing extraction equipment and methods.

In addition to the advantages provided by microwave heating, the extraction method of the present invention advantageously provides an improved liquid tobacco extract having a significantly improved balance of desirable compounds to undesirable compounds and combined with a specifically defined duration of heating. Therefore, an extraction temperature within a certain range is used. In particular, the extraction method of the present invention provides a liquid tobacco extract having a maximum ratio of desired compounds to undesirable compounds for the tobacco material. For example, using a specific combination of extraction temperature and time as defined can optimize levels of nicotine compounds while minimizing levels of undesirable compounds such as furan, carbonyl, phenol and TSNA.

The inventor of the present invention, in contrast to the existing extraction processes discussed above, the method according to the present invention advantageously liquid tobacco having a significantly higher content of compounds associated with the flavor of heated tobacco, such as furaneol for example. It was found that it provides an extract. These compounds are substantially absent or present in trace amounts in tobacco extracts obtained by the maceration process, which usually contain little or no nicotine. These compounds are also generally absent or present in trace amounts in tobacco extracts obtained using solvents, including supercritical conditions. Similarly, tobacco essential oils obtained via distillation processes also have very low levels of these compounds, if any, commonly associated with the flavor of heated tobacco.

The liquid tobacco extract obtained by the method according to the present invention exhibits significant compositional differences with respect to tobacco extracts obtained by conventional extraction processes and, when heated, has a distinct composition and flavor compared to currently available e-liquids. It can be used as an e-liquid or in the preparation of an e-liquid to produce an aerosol with properties. In particular, the liquid tobacco extract obtained by the method according to the invention more closely resembles the aerosol produced by conventional cigarettes compared to available aerosols produced from conventional liquid nicotine compositions, or in devices that do not burn when heated. It can be used to generate an aerosol that provides a heated tobacco taste that heats the tobacco.

The extraction method of the present invention can produce a liquid tobacco extract with optimized levels of nicotine and flavor compounds without the need to add these compounds after extraction. Thus, the final liquid tobacco extract can advantageously be used directly to provide a nicotine composition. The final liquid tobacco extract may also be modified by one or more additional processing steps or mixed with one or more additional ingredients to form a nicotine composition. The nicotine composition may be for use in an electronic cigarette or other aerosol-generating system.

Aerosol-generating systems for delivering an aerosol to a user, including a nebulizer configured to generate an inhalable aerosol from a liquid dosage form, such as a liquid nicotine composition, are known as described above.

The process for producing the liquid tobacco extract of the present invention can be effectively used with all types and grades of tobacco, including Burley tobacco, Yellow tobacco and Oriental tobacco. The method steps can be easily adjusted to provide a consistent liquid tobacco extract for various blends of tobacco types. The extraction method is additionally suitable for various types of tobacco material.

In some cases, the tobacco material can be heated without requiring significant pretreatment steps. Thus, the method can be performed efficiently.

During the process according to the invention, as in many types of prior art extraction processes, the tobacco material is heated directly and is not suspended in a liquid solvent for the heating step. This provides better control over the heating conditions of the tobacco material and also makes the extraction process more efficient. During heating, volatile compounds are released in gaseous form from the tobacco material.

As defined above, in the method according to the invention, the tobacco material is microwave heated in some stages during extraction. Microwave heating is preferably performed before or during the heating step to optimize the effect of microwave heating on extraction yield.

In certain embodiments of the present invention, preparing the tobacco material comprises, prior to the heating step, pre-treating the tobacco material by microwave heating to result in disruption of the tobacco cells. Thus, in the method according to this embodiment, microwave heating of the tobacco material is performed as a pretreatment step prior to the main extraction. Microwave heating, as described above, ruptures the cell walls of the tobacco material and releases nicotine from inside the tobacco cells, making more of the nicotine available for the next heating step.

Preferably, during the pretreatment step the tobacco material is microwave heated to a temperature of about 90°C to about 160°C, more preferably about 95°C to about 110°C.

Preferably, during the pretreatment step, microwave heating is performed for about 1 minute to about 5 minutes.

Optionally, in a method according to the invention in which tobacco material is pretreated by microwave heating, the tobacco material may be cooled to ambient temperature (22° C.) before initiation of the heating step, in order to optimize the effectiveness of the main heating step. In some methods according to the present invention, there may be no cooling step between the microwave pretreatment and the heating step. This may improve the efficiency of the process as the tobacco material may enter the main heating stage at elevated temperatures.

Optionally, the tobacco material is microwave heated in a flow of an inert gas such as nitrogen during a pretreatment step. This is believed to keep the humidity at a relatively low level so that microwave propagation can be optimized. Thus, the positive effect of microwaves on the extraction of nicotine and other compounds can be maximized.

In embodiments where the tobacco material is pretreated by microwave heating prior to the main heating step, as described above, heating the tobacco material to a temperature between 100°C and 160°C can be accomplished by conventional heating, such as resistance heating or steam. This can be done by heating. Conventional heating may be performed, for example, in a conventional oven or dryer. In some embodiments, as described in more detail below, the tobacco material may be subjected to additional microwave heating during the heating step, instead of, or in combination with, conventional heating.

Alternatively or additionally to including a pretreatment step comprising microwave heating, heating the tobacco material to a temperature of between 100°C and 160°C may include microwave heating the tobacco material. In this embodiment, microwave heating of the tobacco material takes place during the main extraction step whereby the heating extracts volatile compounds from the tobacco material in gaseous form. Thus, as described above, microwave heating is used not only to elevate the temperature of the tobacco material to volatilize the tobacco compounds, but also to rupture the tobacco cells to release components from the tobacco cells.

In this embodiment, the step of heating the tobacco material to a temperature between 100°C and 160°C may be performed only by microwave heating.

Alternatively and preferably, heating the tobacco material to a temperature between 100°C and 160°C comprises a combination of microwave heating and conventional heating, such as resistance heating or steam heating. In this method, microwave heating is used in addition to a conventional heating step, and the tobacco material is simultaneously heated by microwaves and conventional heating means, such as resistive heating means or steam. This combination of heating methods has been found to be particularly effective in increasing extraction yields (particularly for nicotine) as the effect of microwave heating appears to be optimized. Also, by combining microwave heating with conventional heating in the main heating step, the heating step can advantageously be carried out much faster and with less energy. Thus, the efficiency of the extraction process is optimized. In certain methods, it is useful to maintain conventional heating in combination with microwave heating rather than using microwave heating alone, as it may be easier to perform certain heating steps by conventional heating means. For example, if the tobacco material is heated with a flow of inert gas, it may be necessary to heat the inert gas with resistance heating means.

Preferably, when a combination of heating methods is used, microwave heating preferably provides about 50% to about 90% of the heating power to heat the tobacco material to the desired brewing temperature.

Microwave heating of tobacco material may be performed using any suitable means for generating microwaves. Examples of suitable devices for microwave heating of tobacco material are SAIREM's LABATRON ^™ ES3 integrated reactor and microwave delivery system, which can be used to perform microwave assisted extraction processes using either batch or continuous flow microwave reactors. This device is suitable for embodiments where the tobacco material is heated simultaneously by microwave and conventional heating, as described above.

The microwave power must be controlled to achieve the desired temperature of the tobacco material, depending on the mass of tobacco material to be heated.

Preferably, the tobacco material is continuously circulated or agitated during microwave heating. This can be achieved, for example, by heating the tobacco material inside the tumble dryer. Continuous circulation of the tobacco material improves the uniformity of heating so that the extraction yield can be optimized by avoiding the formation of hot spots in the tobacco material.

Preferably, the moisture content of the tobacco material at the beginning of the microwave heating step is at least about 10% by weight, more preferably at least about 20% by weight. The moisture content of the tobacco material may be at most about 70% by weight, more preferably at most about 50% by weight, more preferably at most about 40% by weight, and more preferably at most about 30% by weight at the start of the microwave heating step. . For example, the moisture content of the tobacco material at the beginning of the microwave heating step is from about 10% to about 70%, or from about 10% to about 50%, or from about 10% to about 40%, or from about 10% to about 20% by weight.

It will be appreciated that "moisture content in the tobacco material" may include both water inherently present in the tobacco material as well as any added water.

The presence of water in the tobacco material is important to optimize the effectiveness of microwave heating on extraction, as it boils water molecules inside the tobacco cells which can cause cell rupture and release of nicotine and other compounds. Accordingly, the moisture content of the tobacco material is preferably maintained at a level of at least 10% by weight. In particular, drying the tobacco material prior to microwave heating is undesirable, as the cell rupture mechanism is found to be more effective if the tobacco material is not dried prior to microwave heating. Eliminating the drying step at this stage during the extraction process is advantageous because it further improves the overall efficiency of the process compared to prior art extraction processes by reducing the time and energy required to prepare the tobacco material for extraction. am.

In certain embodiments, the method according to the present invention may further comprise the step of applying water to the tobacco material prior to the microwave heating step, preferably to increase the moisture content of the tobacco material to at least 10% by weight. . For example, the tobacco material may be sprayed with liquid water or contacted with steam to increase the moisture content prior to microwave heating.

As described above, in an embodiment of the invention in which the tobacco material is pretreated by microwave heating prior to the main heating step, the method according to the invention is used to increase the moisture content of the tobacco material, preferably by at least 10% by weight, It may further include applying water to the tobacco material after the microwave heating step and before the main heating step. The microwave pretreatment step has the potential to reduce the moisture content of the tobacco material since water evaporates from the inside of the tobacco cells during heating. To ensure that the subsequent heating step for extracting volatile compounds is optimized and any burning of the tobacco material is avoided, it is advantageous to recover the water lost from the tobacco material and bring the moisture content back to at least 10% by weight.

Optionally, in the method according to the invention, water lost during the microwave pre-treatment step can be captured by subjecting the off-gas produced during the pre-treatment step to a condensation process. It may also advantageously capture valuable volatile components of the tobacco that may be lost during the pretreatment step. The collected water and volatile components can then be used to rehydrate the pretreated tobacco. This can rehydrate the tobacco and reduce potential loss of valuable volatile components.

As defined above, in the method of the present invention, tobacco material is heated under specific heating conditions to release volatile tobacco constituents that collect and form a liquid tobacco extract.

During the heating step, the tobacco material is heated to an extraction temperature of about 100°C to about 160°C. Below this range, insufficient levels of nicotine and certain flavor compounds have been found to be released from the tobacco material such that the resulting liquid tobacco extract lacks the desired flavor properties. On the other hand, unacceptably high levels of certain undesirable tobacco compounds may be released when the tobacco material is heated to a temperature in excess of this defined range.

Preferably, the extraction temperature is at least about 110°C, more preferably at least about 115°C, more preferably at least about 120°C, more preferably at least about 125°C.

Preferably, the extraction temperature is about 150°C or less, more preferably about 145°C or less, more preferably about 140°C or less, and most preferably about 135°C or less.

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

The extraction temperature may be about 110°C to about 130°C, about 115°C to about 125°C, or about 120°C.

The extraction temperature may be from about 125°C to about 155°C, more preferably from about 135°C to about 145°C or about 140°C.

Tobacco material for at least about 15 minutes, preferably for at least about 20 minutes, more preferably for at least about 25 minutes, more preferably for at least about 30 minutes, more preferably for at least about 40 minutes, more preferably for at least about 40 minutes Preferably it is heated at the extraction temperature for at least about 50 minutes, more preferably at least about 60 minutes. This extraction time is long enough to provide a liquid tobacco extract from which the desired tobacco flavor compounds can be efficiently extracted to produce an aerosol with the desired flavor properties. As noted above, the inclusion of a microwave heating step in the extraction method of the present invention allows the heating step to be carried out relatively quickly, with a significantly shorter heating duration than is normally required in conventional extraction processes.

Preferably, the tobacco material is heated at the extraction temperature for about 180 minutes or less, more preferably about 120 minutes or less.

For example, the heating time is from about 15 minutes to about 180 minutes, or from about 15 minutes to about 120 minutes, or from about 20 minutes to about 180 minutes, or from about 20 minutes to about 120 minutes, or from about 25 minutes to about 180 minutes , or between about 25 minutes and about 120 minutes, or between about 30 minutes and about 180 minutes, or between about 30 minutes and about 120 minutes, or between about 40 minutes and about 180 minutes, or between about 40 minutes and about 120 minutes, or about 50 minutes minutes to about 180 minutes, or about 50 minutes to about 120 minutes, or about 60 minutes to about 180 minutes, or about 60 minutes to about 120 minutes.

The heating time indicated above corresponds to the duration for which the tobacco material is heated at the brewing temperature and does not include the time taken to increase the temperature of the tobacco material to the brewing temperature.

The extraction temperature and duration of heating may be selected within the range defined above depending on factors such as the type of tobacco, possible other 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 characteristics of the aerosol generated from the liquid tobacco extract. In particular, the ratio of specific tobacco compounds in the liquid tobacco extract can be adjusted to a certain degree through selection of extraction parameters, in order to maximize the ratio of desirable tobacco compounds in the liquid tobacco extract to undesirable tobacco compounds in the liquid tobacco extract.

For a particular tobacco compound, the change in release level of the compound with extraction temperature during the extraction process can be readily determined for any given tobacco material. For example, it has been found that the level of nicotine released from tobacco material generally increases with increasing extraction temperature. The rate of increase was found to vary for different cigarette types.

It is also found that the levels of desirable tobacco flavor compounds such as β-damacinone and β-ionone released from tobacco material will increase with increasing extraction temperature up to a certain peak extraction temperature, after which the levels will begin to decrease. did Peak extraction temperatures for these flavor compounds are typically in the range of 100 °C to 160 °C, so that the desired flavor compound levels can be effectively optimized in the present extraction method.

Many undesirable tobacco compounds have been found to increase slowly with increasing extraction temperature up to a critical temperature, beyond which rapid increases are observed. This applies, for example, to the levels of phenolic compounds, TSNA and pyrazine, and in the case of bright tobacco, to the levels of furan and formaldehyde. In many cases, the critical temperature is in the range of 100 °C to 160 °C, so the level of undesirable compounds can be effectively controlled in the extraction method of the present invention.

Preferably, the extraction temperature and extraction time are selected to provide the liquid tobacco extract with a nicotine content of at least 0.1% by weight, more preferably at least about 0.2% by weight.

Preferably, the extraction temperature and/or extraction time is selected to provide a weight ratio of (β-ionone + β-damacinone) to (phenol) in the liquid tobacco extract of at least about 0.25.

β-Damacinone and β-ionone are preferred compounds related to tobacco flavor. It has been found that the amount of β-damacinone and β-ionone released from tobacco material will increase as the extraction temperature is increased up to a certain peak extraction temperature, after which the levels will begin to decrease. Peak extraction temperatures for these flavor compounds are typically in the range of 100 °C to 160 °C so that the desired flavor compound levels can be effectively tailored and controlled in the extraction method.

Preferably, the extraction temperature and/or extraction time is such that the liquid tobacco extract has a weight ratio of (furaneol + (2,3-diethyl-5-methylpyrazine)*100) to (nicotine) of at least about 5 x 10 ^-4 is chosen to provide

As described above, the heating step may be performed by conventional heating, microwave heating, or a combination of conventional and microwave heating.

Suitable heating methods for performing conventional heating of tobacco material will be known to those skilled in the art and include, but are not limited to, dry distillation, hydro-distillation, vacuum distillation, flash distillation and thin film hydro-distillation.

The heating step is preferably performed in an inert atmosphere. Preferably, a flow of inert gas such as nitrogen is passed through the tobacco material during the heating step. In some cases, a combination flow of inert gas and water or steam may be used. Adding water or steam to the tobacco during extraction has been found to increase the yield of the extracted components. However, excessive addition of water or steam leads to processing difficulties such as stickiness of the tobacco material.

Volatile tobacco compounds are released into the inert gas stream during the heating step so that the inert gas (or water or a combination of steam and inert gas) acts as a carrier for the volatile components. The inert gas flow rate can be optimized based on the size and geometry of the extraction chamber. A relatively high flow rate of inert gas can advantageously improve the efficiency of extraction from tobacco material.

Generally, when heating the tobacco material, any moisture present in the tobacco material is also released along with the volatile compounds in the form of vapors.

The flow of inert gas helps to deliver the vapors produced by evaporation of the moisture content of the tobacco material and volatile compounds—particularly including nicotine or flavor-related compounds or both—from the extraction equipment. It has also been found that in methods wherein the tobacco material is heated by microwave heating during this step, the flow of inert gas advantageously maintains the humidity within the brewing chamber at a relatively low level to maximize the propagation of microwaves through the tobacco material. .

Additionally, using a flow of an inert gas such as nitrogen under some overpressure in the extraction equipment has the advantage of preventing the presence of oxygen within the extraction equipment. This is advantageous in that it avoids the risk of any, even partial combustion of the tobacco material during the heating step. Uncontrolled burning of tobacco material would obviously be undesirable as it could represent a major safety hazard within a manufacturing environment. However, the inventors have found that even limited partial burning of the tobacco material may lead to a decrease in the quality of the tobacco extract obtainable by the method, which is undesirable.

Without being bound by theory, it is understood that by preventing the burning of tobacco material, the formation of any undesirable combustion by-products is also prevented. In addition, as conditions conducive to combustion of the tobacco material are avoided, the tobacco material mimics to some extent the conditions under which a tobacco-containing substrate (e.g., homogenized tobacco material) is typically heated in a “non-combustion-heat” article. heats up effectively under the conditions As a result, the selective extraction of flavor-bearing volatile species responsible for the taste consumers associated with heated tobacco is favorably favored.

Thus, by carrying out the heating step in an inert atmosphere, extraction efficiency, product quality and manufacturing safety are advantageously improved.

Heating the tobacco material with a stream of inert gas has the additional advantage that the stream of inert gas containing volatile compounds can more easily be directed into a vessel containing an extraction solvent, such as a non-aqueous extraction liquid solvent.

Optionally, the heating step may be performed under vacuum. This removes any oxygen present in the brewing chamber, which can advantageously prevent reaction of the tobacco material or volatile compounds generated when the tobacco material is heated with oxygen. Removal of oxygen will also prevent any combustion of the tobacco material, as described above.

The method according to the present invention may further comprise spraying atomized water into the brewing chamber during the heating step. This has been found to improve heat exchange during the heating step, which is believed to be due to the turbulence established in the extraction chamber as a result of evaporation of the atomized water. As a result of the improved heat exchange, it has been found that including spraying water into the brewing chamber during the heating step provides a further improvement in nicotine yield as well as an increase in the yield of certain desirable flavor compounds from the tobacco material. When the heating step includes microwave heating as described above, the presence of water also optimizes the microwave's effect on the tobacco material.

A jet of atomized water may be created and distributed within the extraction chamber using any suitable means.

The rate at which the atomized water is injected into the brewing chamber can be adjusted according to, for example, the flow rate of tobacco material in the brewing chamber. For example, the average rate at which atomized water is injected into the brewing chamber may be from about 3% to about 30% of the tobacco material flow rate.

Preferably, the atomized water is sprayed at a pressure of at least about 1 atmosphere, more preferably at least about 2 atmospheres, more preferably at least about 3 atmospheres.

Methods of spraying water will be known to those skilled in the art. In some embodiments, water may be atomized into a stream of compressed inert gas such as air. In another embodiment, the water can be atomized without gas flow due to the pressure in the spray nozzle.

A liquid tobacco extract can be prepared from tobacco material consisting of a single type of natural tobacco. Alternatively, the tobacco material may comprise a blend of two or more types of natural tobacco. The proportions of the different tobacco types can be adjusted according to the desired properties of the aerosol generated from the liquid tobacco extract. For example, if it is desired to provide a relatively high level of nicotine, the proportion of Burley cigarettes may be increased.

The term "natural tobacco" is used herein with reference to the present invention to describe any part of any plant component of the genus Nicotiana, including but not limited to leaves, stems, stalks and stems. In particular, natural tobacco may include yellow tobacco material, burley tobacco material, oriental tobacco material, Maryland tobacco material, dark tobacco material, fumigated tobacco material, rustica tobacco material, as well as other rare or specialty tobaccos or blends thereof. can As explained in more detail below, the tobacco material may be whole (eg whole tobacco leaves), shredded, cut or ground.

Where it is desired to produce a liquid tobacco extract from a combination of two or more different tobacco types, the tobacco types may be separately heated at different extraction temperatures within a defined range of 100°C to 160°C, or a mixture of tobacco types may be They can be heated together at a single extraction temperature within the range.

Tobacco material may be solid tobacco material such as powder, leaf scraps or shreds, or whole leaves. Alternatively, the tobacco material may be a liquid tobacco material such as a dough, gel, slurry or suspension.

The tobacco material may be derived from any suitable tobacco material including, but not limited to, tobacco leaves, tobacco sacks, reconstituted tobacco, cast tobacco, extruded tobacco or tobacco derived pellets.

Preferably, in the step of preparing the tobacco material, the tobacco is ground or shredded to reduce the size of the tobacco particles in the tobacco material. This may advantageously improve the heating homogeneity and extraction efficiency of the tobacco material.

The tobacco material may optionally be dried prior to the heating step to reduce the water content of the tobacco material. Drying of the tobacco material may be effected by any suitable chemical or physical drying process. Alternatively and preferably, water may be added to the tobacco material prior to the heating step to increase the moisture content of the tobacco material, especially if microwave heating is used during this step.

In certain embodiments of the invention, preparing the tobacco material may include impregnating the tobacco material with an aerosol former. If such impregnation of the tobacco material is performed prior to 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 tobacco material with glycerin has been found to advantageously increase the amount of nicotine extracted from the tobacco material. In another example, impregnating the tobacco material with a non-aqueous extraction solvent that is also an aerosol former, such as propylene glycol, vegetable glycerin, 1,3-propanediol, triacetin, or mixtures thereof, improves flavor extraction from the tobacco starting material. It has been found to advantageously increase the amount of compound.

In some embodiments, the tobacco material consists of natural tobacco that has not undergone any pre-treatment step, for example to control the moisture content. As such, the water content in the tobacco material may be between about 10 and 20% by weight (water content is typically found in natural tobacco material). In another embodiment, the tobacco material may include added water, as described above.

Alternatively or additionally, the tobacco material may include one or more additional ingredients, such as, for example, non-aqueous solvents. One example of a suitable solvent is propylene glycol.

Thus, the tobacco material comprises at least about 40% natural tobacco material, or at least about 60% natural tobacco material, or at least about 80% natural tobacco material, or at least about 90% natural tobacco material, or at least about 95% natural tobacco material, by weight. of natural tobacco material.

In some embodiments, the non-aqueous solvent content is at least about 5% by weight or at least about 10% by weight or at least about 15% by weight or at least about 20% by weight or at least about 25% by weight or at least about 30% by weight or at least about 35% by weight weight percent or at least about 40 weight percent.

Optionally, the tobacco material may be enzymatically degraded prior to the heating step. This has been found to significantly increase the yield of certain flavor compounds from tobacco material.

In certain embodiments, in the step of preparing the tobacco material, the tobacco is not subjected to any treatment adapted to alter the pH of the tobacco. In particular, at the stage of preparing the tobacco material, the tobacco is not subjected to any treatment adapted to significantly increase the pH of the tobacco.

In another embodiment, the method further comprises an alkali treatment of the tobacco material prior to the heating step. When the method includes a pretreatment step of microwave heating the tobacco material, the alkali treatment is preferably carried out prior to microwave heating. During alkali treatment, an alkali solution is preferably applied to the tobacco material to provide an alkalized tobacco material, which is then used for extraction.

Inclusion of an alkali treatment step prior to heating of the tobacco material has been found to provide a further significant increase in the yield of nicotine obtained during extraction.

Preferably, the pH of the alkalized tobacco material is at least about 8.5, more preferably at least about 9.0, even more preferably at least about 9.5. Preferably, the alkalized tobacco material has a pH of 11 or less.

“pH of alkalized tobacco material” refers to the pH of an aqueous suspension of alkalized tobacco material formed by preparing a suspension of alkalized tobacco material in water in a ratio of 1:20. The pH of the suspension is measured after a 30 minute soak time.

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

The tobacco material may optionally be analyzed prior to the heating step to determine the composition, eg the content of reducing sugars of the alkaloids. This information about the composition can be beneficially used to select an appropriate extraction temperature.

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

In certain preferred embodiments, collecting the volatile compounds uses an absorption technique in which the volatile compounds are entrapped in a non-aqueous extraction liquid solvent. For example, an inert gas stream containing volatile compounds may be directed into a vessel of non-aqueous extraction liquid solvent. The non-aqueous extraction liquid solvent is preferably an aerosol former such as triacetin, glycerin, 1,3-propanediol, propylene glycol or combinations thereof. The use of an aerosol former as a liquid solvent is potentially beneficial because the aerosol former can be retained as a diluent in the final liquid tobacco extract. This means that the additional step of removing the non-aqueous extraction solvent is not necessarily necessary.

As used herein with reference to the present invention, the term 'aerosol former' refers to any suitable material that, when in use, facilitates the formation of an aerosol and is preferably substantially resistant to thermal degradation at the operating temperature of the aerosol-generating article or device. refers to a known compound or mixture of compounds. Examples of suitable aerosol formers include polyhydric alcohols such as propylene glycol, triethylene glycol, 1,3-propanediol and glycerin; esters of polyhydric alcohols such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

Preferably, the non-aqueous liquid solvent is maintained at a temperature below 0°C to optimize the transfer of volatile compounds into the liquid solvent. The non-aqueous extraction solvent is preferably maintained at a temperature of -10 °C or higher. Temperatures below these values may lead to undesirable freezing phenomena.

In a preferred alternative embodiment, collecting the volatile compounds may be performed using a condensation technique in which the volatile compounds are condensed and the condensate is collected. Condensation of the volatile compounds can be carried out using any suitable apparatus, for example in a refrigerated column. Preferably, the obtained condensate is added to a liquid aerosol former, preferably propylene glycol.

The addition of liquid aerosol formers, in particular propylene glycol, in the collection step can advantageously prevent the condensed volatile compounds from splitting into two phases or forming emulsions, as some tobacco ingredients tend to do so. . Without being bound by theory, the inventors have observed that the solubility of a tobacco component in the hydroxide (i.e. liquid, aqueous fraction of naturally occurring tobacco extract) depends primarily on its polarity, its concentration and the pH of the hydrolate, which is It can vary depending on the type. As a result, an oily layer tends to form on the surface of the liquid, naturally occurring tobacco extract, if the amount of aerosol former is not sufficient. These oily substances can agglomerate at different locations on the trapping and drying equipment, where the third and further steps of the method are carried out, respectively. The addition of a liquid aerosol former such as propylene glycol helps to prevent the formation of such a layer and favors the homogenization of the liquid, naturally occurring liquid tobacco extract. This, in turn, helps prevent any loss of desired flavor related compounds during the fourth (drying) step, where such compounds may undesirably deposit on equipment surfaces.

In addition, liquid aerosol formers advantageously help entrap flavor-related compounds regardless of their polarity and volatility. In addition, during any subsequent drying step, the liquid aerosol former not only helps to prevent loss of the most volatile fraction, but also optionally removes excess water from the liquid, naturally occurring tobacco extract to obtain a concentrated tobacco extract. help to remove

The use of propylene glycol as an aerosol former for the collection step has the additional advantage that propylene glycol exerts anti-microbial activity by reducing the water activity of the aqueous solution. Thus, by adjusting the content of propylene glycol in the liquid tobacco extract, it is also possible to ensure that the extract does not suffer substantially from any microbial activity.

As another alternative, collecting the volatile compounds may be performed using an adsorption technique in which the volatile compounds are adsorbed onto the surface of a solid adsorbent material such as activated carbon. Then, the adsorbed compound is transferred to a liquid solvent.

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 vary depending on the method of collection. “Collected volatile compounds” will typically include a solution of tobacco-derived volatile compounds in a liquid solvent or carrier.

As described above, where the volatile compounds are collected by absorption in the non-aqueous extraction solvent, the extraction method may include greater than about 25% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. Tobacco extract is provided. In some embodiments, the liquid tobacco extract may comprise greater than about 30% non-aqueous extraction solvent by weight based on the weight of the liquid tobacco extract, or greater than about 35% non-aqueous extraction solvent based on the weight of the liquid tobacco extract. An extraction solvent may be included.

The liquid tobacco extract may include up to about 65% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. In some embodiments, the liquid tobacco extract may comprise 60% or less of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract, or 55% or less of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. can include

In some embodiments, the liquid tobacco extract may comprise from about 25% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract to about 65% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. The liquid tobacco extract may comprise from about 25% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract to about 60% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. The liquid tobacco extract may comprise from about 25% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract to about 55% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract.

In another embodiment, the liquid tobacco extract may comprise from about 30% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract to about 65% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. . The liquid tobacco extract may comprise from about 30% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract to about 60% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. The liquid tobacco extract may comprise from about 30% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract to about 55% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract.

In a further embodiment, the liquid tobacco extract may comprise from about 35% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract to about 65% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. there is. The liquid tobacco extract may comprise from about 35% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract to about 60% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract. The liquid tobacco extract may comprise from about 35% by weight of the non-aqueous extraction solvent based on the weight of the liquid tobacco extract to about 55% by weight 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 mixtures thereof.

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

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 .

Where the volatile compounds are collected by absorption in a liquid solvent as described above, forming the liquid tobacco extract preferably includes drying the solution of the volatile compounds in the liquid solvent to concentrate the solution. This can be done, for example, to reach a desired concentration of nicotine or flavor compound. Drying can be any method including, but not limited to, drying, molecular sieves, freeze drying, phase separation, distillation, membrane permeation, controlled crystallization and filtration of water, reverse hygroscopicity, ultracentrifugation, liquid chromatography, reverse osmosis, or chemical drying. This can be done using any suitable means.

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

That is, a solution of a volatile compound in a liquid solvent is heated to evaporate at least a portion of the water and obtain a concentrated tobacco extract. To this end, a solution of the volatile compound in a liquid solvent may be heated to a temperature and for a time period such that the moisture content in the tobacco extract is reduced by at least about 60%.

Partially dried and concentrated tobacco extract can be considered as the primary product of the process according to the invention. Depleted tobacco mass, in which most of the volatile species and moisture content is extracted upon heating during the second step, can be considered a by-product of the process. Such depleted tobacco material may typically have a moisture content of about 1 to 5% by weight, preferably about 2 to 3% by weight.

In one embodiment, the solution of the volatile compound in a liquid solvent is heated under vacuum, preferably at a temperature of at least about 70°C. In another embodiment, the solution of the volatile compound in a liquid solvent is heated under a flow of air, preferably at a temperature of at least about 35° C., and with a relatively low humidity. Thus, a concentrated tobacco extract of natural origin can be obtained by the method according to the present invention. These naturally derived tobacco concentrate extracts typically contain less than about 20% water by weight.

Alternatively, where volatile compounds are collected by condensation, forming the liquid tobacco extract may include adding the condensate to a liquid solvent, such as an aerosol former.

Optionally, forming the liquid tobacco extract includes a filtration step.

Optionally, forming the liquid tobacco extract includes a blending step in which extracts derived from different tobacco materials are combined.

Optionally, forming the liquid tobacco extract includes adding one or more additives, such as organic acids, to a solution of volatile compounds. However, in many cases, the liquid tobacco extract is suitable for use without additives.

The invention further provides a liquid tobacco extract produced by the method according to the first aspect of the invention, as detailed above. As described above, the process of the present invention advantageously produces a natural liquid tobacco extract having a highly desirable ratio of desired to undesirable tobacco compounds, such as nicotine and flavor compounds.

The liquid tobacco extract is 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.

As used herein, the term “aerosol-generating device” refers to a device comprising a heater element that interacts with a nicotine composition comprising a liquid tobacco extract such as obtained by the method according to the present invention to produce an aerosol. refers to In use, the volatile compounds are released from the nicotine composition by heat transfer and are entrained in the air drawn through the aerosol-generating article. The released compounds condense as they cool, forming an aerosol that is inhaled by the consumer.

Upon heating of a nicotine composition comprising a 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 control of the parameters of the 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.

The nicotine composition may be a liquid tobacco extract resulting from an extraction process according to the present invention, without the addition of additional nicotine. The nicotine composition may be a liquid tobacco extract resulting from the extraction process according to the present invention, without the addition of additional flavor compounds. The nicotine composition may be a liquid tobacco extract resulting from the extraction process according to the present invention, without the addition of additional furaneol. The nicotine composition may be a liquid tobacco extract resulting from the extraction process according to the present invention, without the addition of additional solvent.

Alternatively, the liquid tobacco extract may be subjected to further processing steps to form a nicotine composition. Even with these additional steps, a nicotine composition can be formed without the need to add additional nicotine or flavor compounds.

Preferably, the liquid tobacco extract can be condensed in a drying step as described above to form a condensed tobacco extract, and the condensed tobacco extract can be used to form a nicotine composition.

Preferably, the concentrated tobacco extract comprises 8% to 15% water by weight based on the weight of the concentrated tobacco extract.

The drying step may have a non-aqueous extraction solvent content of about 65% to about 95% by weight, preferably about 65% to about 85% by weight, most preferably about 75% to about 85% by weight. A concentrated tobacco extract is provided. The non-aqueous extraction solvent is preferably triacetin, glycerin, propylene glycol, 1,3-propanediol or mixtures thereof.

The drying step is concentrated tobacco which may have a nicotine content of at least about 0.2% nicotine, preferably from about 0.5% to about 12% nicotine, most preferably from about 2% to about 8% nicotine. provide an extract.

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

The nicotine composition may be a liquid nicotine composition or a gel nicotine composition.

The nicotine composition may include at least about 10% by weight of liquid tobacco extract. Preferably, the nicotine composition includes at least about 20% by weight of liquid tobacco extract. More preferably, the nicotine composition comprises at least about 30% liquid tobacco extract by weight. In a preferred embodiment, the nicotine composition comprises at least about 40% liquid tobacco extract by weight, more preferably at least about 50% liquid tobacco extract by weight, and even more preferably at least about 60% liquid tobacco extract by weight. . In a particularly preferred embodiment, the nicotine composition comprises at least about 65% liquid tobacco extract, more preferably at least about 70% liquid tobacco extract, even more preferably at least about 75% liquid tobacco extract, most preferably at least about 75% liquid tobacco extract. preferably at least about 80% by weight of liquid tobacco extract.

In some embodiments, the liquid tobacco extract is a condensed tobacco extract. The nicotine composition comprises at least about 10% by weight of concentrated tobacco extract, at least about 20% by weight of concentrated tobacco extract, at least about 30% by weight of concentrated tobacco extract, at least about 40% by weight of concentrated tobacco extract, at least about 50% concentrated tobacco extract, preferably at least about 60% concentrated tobacco extract, more preferably at least about 70% concentrated tobacco extract, even more preferably at least about 75% concentrated tobacco extract. concentrated tobacco extract, most preferably at least about 80% by weight concentrated tobacco extract.

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

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

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

The nicotine composition may include up to about 100% by weight of liquid tobacco extract. In some embodiments, the nicotine composition can be formed directly from the liquid tobacco extract without the need to add additional non-aqueous solvents, flavors or nicotine. That is, the nicotine composition may include 100% by weight of liquid tobacco extract. In some embodiments, the liquid tobacco extract is a condensed tobacco extract, such that the nicotine composition can include 100% by weight of the condensed tobacco extract. In embodiments where the nicotine composition comprises 100% liquid tobacco extract or 100% condensed tobacco extract by weight, no additional non-aqueous solvent is present.

Alternatively, in some embodiments, a nicotine composition comprising a liquid tobacco extract may include an additional non-aqueous solvent. Additional non-aqueous solvents are non-aqueous solvents 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 condensed tobacco extract, the nicotine composition comprising the condensed tobacco extract may include an additional non-aqueous solvent.

Additional non-aqueous solvents may be aerosol formers. Preferably, the additional non-aqueous solvent is triacetin, glycerin, propylene glycol, 1,3-propanediol or mixtures thereof.

In embodiments where the nicotine composition includes an additional non-aqueous solvent, the nicotine composition may include up to 90% by weight of the additional non-aqueous solvent. Preferably, the nicotine composition contains no more than 80% by weight of an additional non-aqueous solvent. More preferably, the nicotine composition contains no more than 70% by weight of an additional non-aqueous solvent. In a preferred embodiment, the nicotine composition contains no more than about 60% by weight of the additional non-aqueous solvent, more preferably no more than about 50% by weight of the additional non-aqueous solvent, even more preferably no more than about 40% by weight of the additional non-aqueous solvent. Contains an aqueous solvent. In a particularly preferred embodiment, the nicotine composition comprises no more than about 35% by weight of the additional non-aqueous solvent, more preferably no more than about 30% by weight of the additional non-aqueous solvent, and even more preferably no more than about 25% by weight of the additional non-aqueous solvent. solvent, most preferably up to about 20% by weight liquid tobacco extract.

In the nicotine composition prepared by the method according to the present invention, a nicotine content in the nicotine composition of at least 50% by weight, based on the total weight of the nicotine composition, can be obtained from the tobacco extract, as opposed to being added after extraction. In a preferred embodiment, at least 80% by weight of the nicotine content of the nicotine composition, based on the total weight of the nicotine composition, is obtained from tobacco extract as opposed to being added after extraction. Even more preferably, at least 90% by weight of the nicotine content of the nicotine composition, based on the total weight of the nicotine composition, is obtained from tobacco extract as opposed to being added after extraction.

In the nicotine composition prepared by the method according to the present invention, a non-aqueous extraction solvent content in the nicotine composition of at least 50% by weight, based on the total weight of the nicotine composition, can be obtained from the tobacco extract, as opposed to being added after extraction. In a preferred embodiment, at least 80% by weight of the non-aqueous extraction solvent content of the nicotine composition, based on the total weight of the nicotine composition, is obtained from tobacco extract as opposed to being added after extraction. Even 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, is obtained from tobacco extract as opposed to being added after extraction.

In the nicotine composition prepared by the method according to the invention, a water content in the nicotine composition of at least 50% by weight, based on the total weight of the nicotine composition, can be obtained from the tobacco extract as opposed to being added after extraction. In a preferred embodiment, at least 80% by weight of the water content of the nicotine composition, based on the total weight of the nicotine composition, is obtained from the tobacco extract as opposed to being added after extraction. Even more preferably, at least 90% by weight of the water content in the nicotine composition, based on the total weight of the nicotine composition, is obtained from the tobacco extract as opposed to being added after extraction.

In a nicotine composition prepared by a method according to the present invention, a desired tobacco flavor species content in the nicotine composition of at least 50% by weight, based on the total weight of the nicotine composition, can be obtained from the tobacco extract as opposed to being added after extraction. In a preferred embodiment, at least 80% by weight of the desired tobacco flavor species content in the nicotine composition, based on the total weight of the nicotine composition, is obtained from tobacco extract as opposed to being added after extraction. Even more preferably, at least 90% by weight of the preferred tobacco flavor species content in the nicotine composition, based on the total weight of the nicotine composition, is obtained from tobacco extract as opposed to added after extraction.

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

The nicotine composition may include a total amount of propylene glycol from about 10% to about 95% by weight. The nicotine composition is about 20% to about 95% by weight, such as about 50% to about 95%, or about 65% to about 95%, about 70% to about 90%, or about 80% by weight. to about 90% by weight of the total amount of propylene glycol.

The nicotine composition may include a total amount of triacetin from about 10% to about 95% by weight. The nicotine composition is about 20% to about 95% by weight, such as about 50% to about 95%, about 70% to about 90%, or about 65% to about 95%, or about 80% by weight. to about 90% by weight of triacetin.

The nicotine composition may include a total amount of glycerin from about 10% to about 95% by weight. The nicotine composition is about 20% to about 95% by weight, such as about 50% to about 95%, or about 65% to about 95%, about 70% to about 90%, or about 80% by weight. to about 90% by weight of the total amount of glycerin.

The nicotine composition may include a total amount of 1,3-propanediol from about 10% to about 95% by weight. The nicotine composition may contain from about 20% to about 95%, such as from about 50% to about 95%, or from about 65% to about 95%, or from about 80% to about 90% 1,3- It may include the total content of propanediol.

The nicotine composition of the present invention contains at least 0.2% nicotine by weight. More preferably, the nicotine content of the nicotine composition liquid tobacco extract is at least about 0.4% by weight. The nicotine composition will have a nicotine content of about 12% or less, for example about 10% or less, preferably about 8% or less, more preferably about 5% or less, preferably about 3.6% or less. can Most preferably, the nicotine composition comprises about 0.4% to 3.6% nicotine by weight, based on the weight of the nicotine composition.

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

In some embodiments, the nicotine composition may include one or more water soluble organic acids. As used herein in connection with the present invention, the term "water-soluble organic acid" describes an organic acid having a solubility in water of greater than about 500 mg/ml at 20°C.

The one or more water-soluble organic acids may advantageously bind nicotine in the liquid nicotine extract through the formation of one or more nicotine salts. The one or more nicotine salts may advantageously be soluble and stabilized in liquid tobacco extract or water present in a non-aqueous solvent. This may advantageously reduce nicotine uptake in the upper respiratory tract and improve pulmonary nicotine delivery and retention as discussed above.

Preferably, the nicotine composition has a water-soluble organic acid content of greater than about 2% by weight. More preferably, the nicotine composition has a water-soluble organic acid content of at least about 3% by weight.

The water-soluble organic acid may be acetic acid.

Exogenous acetic acid is acetic acid added from a source other than tobacco plant material and is not acetic acid naturally present in tobacco plants that is separated, removed, or derived from tobacco plant material using extractive treatment conditions and techniques.

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

Preferably, the nicotine composition has a water-soluble organic acid content of less than about 8% by weight. More preferably, the nicotine composition has a water-soluble organic acid content of about 6% by weight or less.

Preferably, the nicotine composition has a water-soluble organic acid content of about 2% to about 8% by weight. For example, the nicotine composition may have a water-soluble organic acid content of about 2% to about 6% by weight.

More preferably, the nicotine composition has a water-soluble organic acid content of about 3% to about 8% by weight. For example, the nicotine composition may have a water-soluble organic acid content of about 3% to about 6% by weight.

The nicotine composition may include one or more non-tobacco-derived flavoring agents. Suitable non-tobacco-derived flavoring agents include, but are not limited to, menthol.

Preferably, the nicotine composition has a non-tobacco-derived flavor content of less than about 4% by weight. More preferably, the nicotine composition has a non-tobacco-derived flavor content of about 3% by weight or less. For example, the liquid tobacco extract produced by the method of the present invention can be used to prepare a nicotine composition comprising 10 to 20 mg of nicotine per milliliter without the need for added nicotine.

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

A 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 include an atomizer configured to generate an aerosol from the nicotine composition. The nebulizer may be a thermal nebulizer configured to heat the nicotine composition to generate an aerosol. A thermal atomizer may include, for example, a heater and a liquid delivery element configured to deliver a nicotine composition to the heater. The liquid transfer element may include a capillary wick. Alternatively, the nebulizer may be a non-thermal nebulizer configured to generate an aerosol from the nicotine composition by means other than heating. For example, the non-thermal nebulizer may be an impingement jet nebulizer, an ultrasonic nebulizer, or a vibrating mesh nebulizer.

A cartridge containing a nicotine composition formed from the liquid tobacco extract of the present invention may be used with any suitable aerosol-generating device comprising a housing configured to receive at least a portion of the cartridge. The aerosol-generating device may include a battery and control electronics.

Specific embodiments of the present invention will now be further described by way of example only.

In the extraction method according to the first embodiment, the tobacco material is prepared from yellowish bright tobacco material. The tobacco material is cut to form a tobacco shred having a maximum dimension of 2.5 mm x 2.5 mm, and the tobacco shred is pretreated by microwave heating until it causes the tobacco cells to burst. The pretreated tobacco shreds are cooled and then placed in a moisture chamber to increase the moisture content to about 10% by weight. The tobacco shred is then fed into the brewing chamber at a rate of 30 kg/hour of tobacco without compression. Tobacco material is heated to a temperature of 130° C. for 2 hours in the brewing chamber. During heating, a flow of nitrogen is passed through the extraction chamber at a flow rate of about 20 liters per minute.

Volatile compounds released from the tobacco material during the heating step were collected by condensation at 0 °C and added to a liquid solvent formed from propylene glycol.

The solution of propylene glycol with collected volatile compounds is concentrated in the drying process to reduce the moisture level of the liquid tobacco extract to approximately 15%.

In the extraction method according to the second embodiment, the tobacco material is prepared from yellowish bright tobacco material. The tobacco material is cut to form a tobacco shred having dimensions of 2.5 mm x 2.5 mm, and water is applied to the tobacco material to increase the moisture content to about 20% by weight. Tobacco shreds are loaded into the brewing chamber without compression. Tobacco material is heated to a temperature of 130° C. for a period of 30 minutes in the brewing chamber. The heating is performed by a combination of microwave heating and resistance heating, with the microwave heating providing at least 50% of the power to heat the tobacco material. During heating, a flow of nitrogen is passed through the extraction chamber at a flow rate of about 40 liters per minute.

Volatile compounds released from the tobacco material during the heating step were collected by condensation at 0 °C and added to a liquid solvent formed from propylene glycol. The solution of propylene glycol with collected volatile compounds is concentrated in the drying process to reduce the moisture level of the liquid tobacco extract to approximately 15%.

Claims (15)

A method for preparing a liquid tobacco extract, the method comprising:
preparing a tobacco material;
heating the tobacco material at an extraction temperature of 100° C. to 160° C. for at least 15 minutes;
collecting volatile compounds released from the tobacco material during the heating step; and
Forming a liquid tobacco extract containing the collected volatile compounds,
wherein the tobacco material is microwave heated during at least one step of the method. 2. The method of claim 1, wherein preparing the tobacco material comprises, prior to the heating step, pre-treating the tobacco material by microwave heating to result in disruption of the tobacco cells. 3. The method of claim 2, wherein the step of heating the tobacco material to an extraction temperature of 100°C to 160°C is performed by conventional heating. 4. The method of any one of claims 1-3, wherein heating the tobacco starting material to an extraction temperature between 100°C and 160°C comprises microwave heating the tobacco material. 5. The method of claim 4, wherein heating the tobacco material to an extraction temperature between 100°C and 160°C comprises heating the tobacco material by a combination of microwave heating and conventional heating. 6. A method according to any preceding claim, wherein the tobacco material, if present, is heated in a flow of inert gas during at least one of the heating step and the pretreatment step. 7. A method according to any one of claims 1 to 6, wherein the tobacco material has a moisture content of at least 10% by weight at the start of the microwave heating. 8. The method of any one of claims 1 to 7, further comprising applying water to the tobacco material prior to the microwave heating step to increase the moisture content of the tobacco material to at least 10% by weight. method. 9. A method according to any one of claims 1 to 8, wherein the tobacco material is continuously cycled during the microwave heating. 10. The method according to any one of claims 1 to 9, wherein the tobacco material is heated at an extraction temperature of 125°C to 160°C. 11. A method according to any one of claims 1 to 10, wherein the extraction temperature is selected to provide a liquid tobacco extract having a nicotine content of at least 0.2% by weight on a dry weight basis. 12. A method according to any one of claims 1 to 11, further comprising subjecting the tobacco material to an alkali treatment prior to the heating step and, if present, prior to the pretreatment step. 13. The method of any one of claims 1 to 12, further comprising spraying water atomized onto the tobacco material during the heating step. 14. The method of any one of claims 1 to 13, further comprising drying or concentrating the collected volatile compounds. A liquid tobacco extract prepared by the method of any one of claims 1 to 14.