METHOD OF MAKING A TOBACCO EXTRACT

Abstract

The invention provides Embodiments described herein include a method of making a tobacco extract comprising; (a) providing tobacco and an entrapment solvent in a partitioned vessel, wherein the tobacco and entrapment solvent are separated by the partition, and the vessel is configured such that the tobacco and entrapment solvent cannot contact each other; (b) flowing a supercritical extraction solvent through the vessel, wherein the extraction solvent and any dissolved substances can pass through the partition; whereby tobacco components are extracted from the tobacco into the extraction solvent and carried across the partition, wherein the extraction solvent contacts the entrapment solvent and tobacco components are transferred from the supercritical extraction solvent into the entrapment solvent.

Claims

1. A method of making a tobacco extract, the method comprising; (a) providing tobacco and an entrapment solvent in a partitioned vessel, wherein the tobacco and entrapment solvent are separated by a partition, and the vessel is configured such that the tobacco and entrapment solvent cannot contact each other; (b) flowing a supercritical extraction solvent through the vessel, wherein the extraction solvent and any dissolved substances can pass through the partition; whereby tobacco components are extracted from the tobacco into the extraction solvent and carried across the partition, wherein the extraction solvent contacts the entrapment solvent and tobacco components are transferred from the extraction solvent into the entrapment solvent.

2. The method of claim 1, wherein the partition is selected from the group consisting of: a bubble cap tray, a sieve plate, a valve plate, a sinter plate, and a very fine mesh.

3. The method of claim 1, further comprising: (c) altering the conditions in the vessel so that the extraction solvent is subcritical, thereby separating the extraction solvent and any remaining dissolved tobacco components, at least some of which are subsequently dissolved in the entrapment solvent.

4. The method according to claim 1, wherein the extraction solvent comprises carbon dioxide.

5. The method according to claim 4 wherein, during (a) and (b), the temperature is in the range of about 308-473K, preferably about 328-350K, and the pressure is in the range of about 8-85 MPa, preferably about 20-30 MPa.

6. The method according to claim 1, wherein the entrapment solvent comprises an aerosol generating agent.

7. The method according to claim 6, wherein the entrapment solvent comprises a polyol, such as glycerol and/or propylene glycol.

8. The method according to preceding claim 1, wherein the tobacco components include one or more of nicotine and tobacco aromas and flavors.

9. The method according to claim 1, wherein the entrapment solvent is provided in an upper portion of the vessel, above the tobacco in a lower portion, and the partition is selected from the group consisting of a bubble cap tray, a sieve plate, and a valve plate.

10. The method according to claim 1, wherein the entrapment solvent is provided in a lower portion of the vessel, below the tobacco in an upper portion, and the partition is selected from the group consisting of a sinter plate and a very fine mesh.

11. The method according to claim 1, further comprising providing the entrapment solvent containing dissolved tobacco components in a cartridge, wherein the cartridge is configured for use in a smoking article.

12. A tobacco extract obtainable by the method of claim 1.

13. A cartridge configured for use in a smoking article, the cartridge containing a tobacco extract according to claim 12.

14. A smoking article containing a tobacco extract according to claim

12.

15. Use of a tobacco extract obtainable by a method according to claim 1 to generate an inhalable aerosol.

16. Use of a tobacco extract according to claim 15, wherein the tobacco extract is used in a smoking article.

7. A method according to claim 6, wherein the entrapment solvent comprises a polyol, such as glycerol and/or propylene glycol.

8. A method according to any preceding claim, wherein the tobacco components include one or more of nicotine and tobacco aromas and flavours.

9. A method according to any preceding claim, wherein the entrapment solvent is provided in an upper portion of the vessel, above the tobacco in a lower portion, and the partition is in the form of a bubble cap tray, sieve plate or valve plate.

10. A method according to any one of claims 1 to 8, wherein the entrapment solvent is provided in a lower portion of the vessel, below the tobacco in an upper portion, and the partition is in the form of a sinter plate or a very fine mesh.

11. A method according to any preceding claim, further comprising the step of providing the entrapment solvent containing dissolved tobacco components in a cartridge, wherein the cartridge is configured for use in a smoking article.

12. A tobacco extract obtainable by a method according to any one of claims 1 to 10.

13. A cartridge configured for use in a smoking article, the cartridge containing a tobacco extract according to claim 12.

14. A smoking article containing a tobacco extract according to claim 12.

15. Use of a tobacco extract obtainable by a method according to any one of claims 1 to 10 to generate an inhalable aerosol.

16. Use according to claim 15, wherein the tobacco extract is used in a smoking article.

Description

DETAILED DESCRIPTION

[0030] For the avoidance of doubt, the term “tobacco extract” as used herein refers to the entrapment solvent containing tobacco components.

[0031] A supercritical fluid is any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist. Supercritical fluids can effuse through solids like a gas, and dissolve materials like a liquid. Supercritical fluids have a higher fluid density than gases and therefore have a higher solvent capacity.

[0032] In some cases, one or more flavors may be added to the tobacco extract. As used herein, the term “flavor ” refers to materials which, where local regulations permit, may be used to create a desired taste or aroma in a product for adult consumers. They may include extracts (e.g., licorice, hydrangea, Japanese white bark magnolia leaf, chamomile, fenugreek, clove, menthol, Japanese mint, aniseed, cinnamon, herb, wintergreen, cherry, berry, peach, apple, Drambuie, bourbon, scotch, whiskey, spearmint, peppermint, lavender, cardamom, celery, cascarilla, nutmeg, sandalwood, bergamot, geranium, honey essence, rose oil, vanilla, lemon oil, orange oil, cassia, caraway, cognac, jasmine, ylang-ylang, sage, fennel, piment, ginger, anise, coriander, coffee, or a mint oil from any species of the genus Mentha), flavor enhancers, bitterness receptor site blockers, sensorial receptor site activators or stimulators, sugars and/or sugar substitutes (e.g., sucralose, acesulfame potassium, aspartame, saccharine, cyclamates, lactose, sucrose, glucose, fructose, sorbitol, or mannitol), and other additives such as charcoal, chlorophyll, minerals, botanicals, or breath freshening agents. They may be imitation, synthetic or natural ingredients or blends thereof. They may be in any suitable form, for example, oil, liquid, or powder.

[0033] As used herein, an “aerosol generating agent” is an agent that promotes the generation of an aerosol on heating. An aerosol generating agent may promote the generation of an aerosol by promoting an initial vaporization and/or the condensation of a gas to an inhalable solid and/or liquid aerosol.

[0034] In general, suitable aerosol generating agents include, but are not limited to: a

[0035] polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, high boiling point hydrocarbons, acids such as lactic acid, glycerol derivatives, esters such as diacetin, triacetin, triethylene glycol diacetate, triethyl citrate or myristates including ethyl myristate and isopropyl myristate and aliphatic carboxylic acid esters such as methyl stearate, dimethyl dodecanedioate and dimethyl tetradecanedioate. In some cases, the aerosol generating agent comprises one or more of glycerol, propylene glycol, triacetin and isopropyl myristate, suitably glycerol and/or propylene glycol.

[0036] The weight ratio of aerosol generating agent to tobacco (dry weight) may be from about 2:1 to about 1:3, suitably from 3:2 to about 1:2, suitably about 1:1.

[0037] The method according to the invention may additionally comprise an initial step of adding water to the tobacco. The amount of water added may be from about 2% to about 20% based on the dry weight of tobacco, suitably from about 2%, 5% or 8% to about 12%, 15%, 18% or 20%. This pre-treatment with water increases the transfer of polar tobacco components (such as flavors) from the tobacco to the entrapment solvent.

[0038] In the process according to the invention, a higher pressure under supercritical conditions increases the solvent capacity and increases the efficiency of extraction. However, more energy is required to achieve and maintain higher pressures. Thus, the supercritical conditions are suitably selected to balance these conflicting requirements.

[0039] Where the supercritical fluid comprises carbon dioxide, the pressure at which extraction occurs may, in some cases, be from about 8 MPa, 10 MPa, 15 MPa, 20 MPa or 25 MPa to about 85 MPa, 70 MPa, 55 MPa, 40 MPa or 30 MPa, suitably from 8-85 MPa, 15-40 MPa or 20-30 MPa. Where the supercritical fluid comprises carbon dioxide, the temperature at which extraction occurs may, in some cases, be from about 308K, 318K or 328K to about 473K, 430K, 390K or 350K, suitably from 308-473K, 308-430K, or 328-350K.

EXAMPLES

[0040] Analytical Methods

[0041] Water activity values reported below were measured at 24.9-25.2° C. using the Aqualab Prewater Activity meter. The values were determined using the dewpoint method.

[0042] Viscosity values reported below were measured at 25° C. using a Gemini Rheometer from Bohlin Instruments.

[0043] Pre-Extraction (Pre-Treatment of Tobacco):

[0044] Ground Virginia tobacco leaf of the particle size ranging from 355 μm to 3.5 mm was pre-treated by addition of water (10% of total tobacco weight). The mixture of tobacco and water was left for equilibration for 15 minutes post water addition (which is sufficient time for the water to be fully absorbed).

Example 1: Example of Process According to the Invention

[0045] A stainless steel extraction vessel (5 L autoclave) with a solvent inlet at the base and outlet at the top, and an external circulation line connecting the outlet with the inlet, was loaded with pre-treated tobacco (1.2 kg plus 10wt % water); the tobacco was placed on a stainless steel sintered plate in the bottom of the extraction vessel. The sintered plate distributes the supercritical fluid which enters the extraction vessel via a narrow inlet below the tobacco.

[0046] Filter paper was placed on top of the tobacco to hold tobacco particles in place and prevent them moving around the circulation loop/piping.

[0047] A liquid trap containing 0.5 kg of glycerol was placed on the top of the tobacco. Carbon dioxide may suitably be pumped through the system at the rate 5-23 kg/hr.

[0048] In this instance, carbon dioxide was pumped through the system at the rate 10 kg/hr while the extraction chamber and circulation line were maintained at 26 MPa and 338 K. At these conditions, carbon dioxide is supercritical.

[0049] The supercritical CO2 fluid flowed through the bed of ground tobacco and dissolved components of tobacco. The flow of supercritical CO2 containing tobacco constituents then passed through the glycerol, tobacco components transferred into the glycerol.

[0050] CO2 was circulated for 180 minutes and the system was then depressurized. Separation of the extract from the supercritical CO2 occurred during the depressurization stage. Removal of CO2 was achieved by pressure and temperature reduction with absorption of the extracted compounds in glycerol.

[0051] Comparative Test

[0052] A comparative test was run using the same conditions as example 1. However, the apparatus was different. 1.2 kg of glycerol was provided in a separation chamber, which is distinct from the extraction chamber. The separation and extraction chambers were linked by a transfer line. The supercritical solvent was circulated through the two chambers.

[0053] All other aspects of the comparative test were the same as in example 1.

[0054] The comparative test is a representative example of the processes described generally in EP1915064.

[0055] Data

[0056] Tobacco Extract Properties:

TABLE-US-00001 Water Nicotine Water NNN NNK Viscosity Density activity Experiment (mg/g) (wt %) (ng/g) (ng/g) (Pa s) pH (g/cm.sup.3) (Aw) Example 1 5.28 8.18 53.9 38 0.24 6.33 1.24 0.3 Comp. Test 4.7 5.5 71.1 49.1 0.32 6.73 1.25 0.24

[0057] Surprisingly, it can be seen that using a single chamber configuration (example 1) rather than a multi-chamber arrangement (comparative test) alters the composition of the extract.

[0058] Similar results have been observed when using Oriental or Burley starting tobaccos.

[0059] The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and/or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilized and modifications may be made without departing from the scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc., other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.