KR102526557B1 - Method for preparing tobacco extract - Google Patents

Abstract

The present invention is a method for preparing a tobacco extract,
(a) contacting tobacco with an extraction solvent to extract tobacco components from the tobacco with the extraction solvent, wherein the extraction solvent comprises a supercritical fluid;
(b) separating residual tobacco solids from the extraction solvent containing tobacco components;
(c) releasing tobacco components from the extraction solvent by providing a capture solvent in a vessel and exposing the extraction solvent containing tobacco components to conditions in the vessel such that the extraction solvent is subcritical, wherein the capture solvent is extracted Dissolving the released tobacco components from the solvent is provided.

Description

Method for preparing tobacco extract

The present invention relates to a method for preparing a tobacco extract and a tobacco extract produced in the process. The present invention also provides cartridges containing tobacco extract for use in smoking articles, and smoking articles comprising tobacco extract.

Tobacco material is heated in a smoking article to release substances contained in the tobacco material and deliver them as an aerosol.

Smoking articles such as cigarettes, cigars, and the like burn tobacco during use to produce tobacco smoke. Attempts have been made to provide an alternative to these articles that burn tobacco by creating products that release compounds without burning. An example of such a product is a heating device that releases a compound by heating the material but not burning it. This material may be, for example, tobacco or other non-tobacco products, which may or may not contain nicotine.

The electronic cigarette or "e-cigarette" is another product designed as an alternative to combustible products. The device contains a volatile solution which, when heated, generates an inhalable aerosol. This solution may contain tobacco components. Therefore, it is useful to be able to selectively extract tobacco components.

EP1915064 describes a process for making reconstituted tobacco comprising a tobacco extraction step. The extraction process uses supercritical carbon dioxide to extract tobacco components and then contacts the supercritical carbon dioxide-containing tobacco components with propylene glycol. Tobacco components are transferred to propylene glycol. Carbon dioxide is entirely supercritical.

summary

According to a first aspect of the present invention, as a method for producing a tobacco extract,

(a) contacting tobacco with an extraction solvent to extract tobacco components from the tobacco with the extraction solvent, wherein the extraction solvent comprises a supercritical fluid;

(b) separating residual tobacco solids from the extraction solvent containing tobacco components;

(c) releasing tobacco components from the extraction solvent by providing a capture solvent in a vessel and exposing the extraction solvent containing the tobacco components to conditions in the vessel such that the extraction solvent is subcritical, wherein the capture solvent is extracted A method comprising dissolving released tobacco components from a solvent is provided.

The inventors have established that changes in the extraction process using supercritical extraction solvents result in changes in tobacco extract composition and/or physical properties of the extract.

The presence of the trapping solvent results in a tobacco extract that is readily suitable for use in e-cigarettes and the like. Shifting to subcritical conditions enables efficient and effective separation of tobacco components and extraction solvent. This means a higher concentration of tobacco components in the capture solvent (ie in the tobacco extract) and a different chemical composition compared to the process of EP1915064 (where the extraction solvent is entirely supercritical). This enhances the organoleptic properties of the extract.

The use of subcritical conditions for the separation is also advantageous over processes in which the extraction solvent is entirely supercritical because less energy is required to maintain the conditions. Thus, the process is more energy efficient, has lower operating costs and is faster to install.

In some cases, the capture solvent includes an aerosol generating agent. In some cases, the capture solvent consists essentially of or consists of one or more aerosol generating agents.

In some cases, the extraction solvent used in the process includes carbon dioxide. In some cases, the extraction solvent consists essentially of or consists of carbon dioxide.

In some cases, the capture solvent used in the method includes a polyol. In some cases, the capture solvent includes glycerol and/or propylene glycol. In some cases, the capture solvent consists essentially of or consists of glycerol.

In some cases, tobacco components extracted by the methods described herein include one or more of nicotine and tobacco aromas and flavorings.

In some cases, the methods described herein may further include providing a capture solvent containing dissolved tobacco components (ie, tobacco extract) in a cartridge, wherein the cartridge is configured for use in a smoking article.

In some cases, steps (a) and (c) are completed in separate vessels. Step (a) may be completed in a first vessel (or extraction vessel) in which the extraction solvent is maintained at a supercritical temperature and pressure throughout. Step (c) may be completed in a second vessel (or separate vessel) in which the extraction solvent is maintained at a subcritical temperature and pressure throughout. In some cases, step (b) comprises transferring the extraction solvent containing tobacco components from the extraction vessel to a separation vessel.

According to a second aspect of the present invention there is provided a tobacco extract obtained or obtainable by the method described herein.

According to a further aspect, a cartridge configured for use in a smoking article is provided, the cartridge containing a tobacco extract obtained or obtainable by a method described herein. The cartridge may be configured for use in an electronic cigarette.

According to a further aspect there is provided the use of a tobacco extract obtained or obtainable by the method described herein for generating an inhalable aerosol. In some cases, tobacco extracts are used in smoking articles to generate smokeable aerosols.

According to a further aspect, a smoking article containing a tobacco extract obtained or obtainable by a method described herein is provided. In some cases, smoking articles may contain tobacco extract in an insertable cartridge, the cartridge being configured for use in a smoking article. The smoking article may further include a mouthpiece. The smoking article may further include a heater that volatilizes the capture solvent containing the tobacco extract when in use.

The smoking article may be an electronic cigarette.

Additional features and advantages of the present invention will become apparent from the following description of preferred embodiments of the present invention, given by way of example only.

details

For the avoidance of doubt, the term "tobacco extract" as used herein refers to a capture solvent containing tobacco components.

A supercritical fluid is any substance at a temperature and pressure above its critical point in which there are no inherent liquid and gas phases. Supercritical fluids can flow through solids like gases and dissolve substances like liquids. Supercritical fluids have a higher fluid density than gases and therefore have a higher solvent capacity.

In some cases, one or more flavoring agents may be added to the tobacco extract. As used herein, the term "flavor" refers to a substance that may be used to create a desired taste or aroma in products for adult consumers, where permitted by local regulations. They are extracts (e.g. licorice, hydrangea, Japanese white magnolia leaf, chamomile, fenugreek, cloves, menthol, Japanese mint, anise seed, cinnamon, herbs, wintergreen, cherry, berry, peach, apple, drambu). (Drambuie), Bourbon, Scotch, Whiskey, Spearmint, Mint, 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, pigment, ginger, anise, coriander, coffee or any species of Mentha oil from the genus Mentha), flavor enhancer, bitter receptor site blockers, sensory receptor site activators or stimulants, sugars and/or sugar substitutes (e.g., sucralose, acesulfame potassium, aspartame, saccharin, cyclamate, lactose, sucrose, glucose, fructose, sorbitol or mannitol) , and other additives such as charcoal, chlorophyll, minerals, botanicals, or breath fresheners. They may be imitations, synthetic or natural ingredients or blends thereof. They may be in any suitable form, for example oil, liquid or powder.

As used herein, an "aerosol generating agent" is an agent that promotes generation of an aerosol upon heating. An aerosol generating agent may promote generation of an aerosol by facilitating initial vaporization and/or condensation of a gas into an inhalable solid and/or liquid aerosol.

In general, suitable aerosol generating agents include polyols such as sorbitol, glycerol, and glycols such as propylene glycol or triethylene glycol; Non-polyols such as monohydric alcohols, high boiling hydrocarbons, acids such as lactic acid, glycerol derivatives, esters such as diacetin, triacetin, triethylene glycol diacetate, triethyl citrate, or ethyl myristate and isopropyl myristate myristate, and aliphatic carboxylic acid esters such as methyl stearate, dimethyl dodecanedioate, and dimethyl tetradecanedioate, but are not limited thereto. 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.

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

The method according to the present invention may further comprise an initiation step of adding water to the tobacco. The amount of water added may be from about 2% to about 20%, suitably from about 2%, 5% or 8% to about 12%, 15%, 18% or 20% by dry weight of the tobacco. This pretreatment with water increases the migration of polar tobacco components (eg flavorings) from the tobacco into the capture solvent.

In the process according to the present invention, higher pressures under supercritical conditions increase the solvent capacity and increase the extraction efficiency. However, more energy is required to achieve and maintain higher pressures. Therefore, supercritical conditions are appropriately chosen to balance these conflicting requirements. When the supercritical fluid includes carbon dioxide, the pressure at which extraction occurs is in some cases 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, it may be 8-85 MPa, 15-40 MPa or 20-30 MPa. In some cases, the pressure may be about 10-16 MPa, suitably about 12 MPa, or about 20-26 MPa, suitably about 23 MPa; We found that the concentration of TSNA in tobacco extracts is lower when extraction is complete at these pressures.

When the supercritical fluid comprises carbon dioxide, the temperature at which extraction occurs is in some cases from about 308K, 318K or 328K to about 473K, 430K, 390K or 350K, suitably 308-473K, 308-430K, or 328-350K. can

Shifting to subcritical conditions reduces the fluid density of the extraction solvent and consequently results in precipitation of tobacco components. The conditions should be such that the pressure is below the critical pressure of the extraction solvent and/or the temperature is below the critical temperature of the extraction solvent. For thermal efficiency, conditions where the temperature is maintained above the critical temperature while the pressure is below the critical pressure of the extraction solvent are suitable.

The separation efficiency of the tobacco components and the extraction solvent improves as conditions move further below the critical point of the extraction solvent. However, the extraction solvent will typically be collected and stored after separation (requires compression) and, in some cases, may be recycled to the extraction chamber. Therefore, it is suitable that the subcritical condition is not too far below the critical point to improve energy efficiency. Subcritical conditions are appropriately chosen to balance these conflicting requirements. When the extraction solvent includes carbon dioxide, the pressure at which extraction occurs is in some cases from about 3 MPa, 4 MPa, 5 MPa, or 5.5 MPa to about 7.3 MPa, 7 MPa, 6.5 MPa, 6 MPa, 5.5 MPa, or 5 MPa, suitably Preferably it may be 3-7.3 MPa, or 4-6 MPa. When the extraction solvent comprises carbon dioxide, the temperature of the subcritical condition at which the separation occurs is in some cases from about 280K, 300K, 320K or 330K to about 473K, 430K, 390K or 350K, suitably 308-473K, 308-430K, or 328-350K.

Example

analysis method

The water activity values reported below were measured at 24.9-25.2° C. using an Aqualab Prewater Activity meter. This value was determined using the dewpoint method.

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

Before extraction (pre-treatment of tobacco):

Ground Virginia tobacco leaves of particle size ranging from 355 μm to 3.5 mm were pretreated by addition of water (10% of total tobacco weight). The mixture of tobacco and water was allowed to equilibrate for 15 minutes after water addition (this is sufficient time for the water to be completely absorbed).

Pretreated tobacco (1.2 kg + 10 wt% water) was placed in a stainless steel extraction basket and the basket was placed in an extraction vessel (5 L autoclave). The basket was closed at its ends by sintered metal plates (pore diameter 100 μm, pressure drop across the plate less than 1 bar), which distributed the supercritical fluid at the inlet and prevented the outflow of solid particles at the outlet. The use of baskets also allowed for rapid charging and discharging of the extraction vessels. The basket was sealed against the extraction vessel wall so that no supercritical fluid flowed around it.

Example 1: Example of a process according to the invention

The extraction vessel was connected to the separation vessel by a transfer line. A pressure regulating valve was present in the line. Carbon dioxide can suitably be pumped through the system at a rate of 5-23 kg/hr. In this case, carbon dioxide was pumped through the system at a rate of 10 kg/hr. 1.2 kg of glycerol was provided in a separate vessel.

The extraction chamber was maintained at 26 MPa and 338K, and the separation chamber was maintained at 4.5 MPa and 318K. Precipitation of the extract in the separation chamber was achieved by reducing pressure and temperature (from supercritical to subcritical conditions), which reduced the fluid density of carbon dioxide and thus the solvent power of CO ₂ . The extracted tobacco components were collected in glycerol at the bottom of the separator.

Gaseous CO ₂ exited the separator after passing through a liquid/gas divider (which removed any residual liquid extract entrained in the gas). CO ₂ was collected and recycled to the extraction chamber.

The process was run for 3 hours before the CO ₂ flow was turned off. The system was depressurized (to atmospheric conditions). Thereafter, the glycerol containing tobacco components was discharged from the separation vessel and weighed.

comparison test

A comparative test was conducted using the same apparatus as in Example 1. However, conditions were supercritical (26 MPa and 338 K) throughout the device. All other aspects of the comparative test were the same as in Example 1.

The comparative test is representative of the process generally described in EP1915064.

data

Tobacco Extract Properties:

^* The process of Example 1 was performed 6 times. Where ranges are provided in the data tables, all examples are included in those ranges. If a single value is provided, the value is an average value.

It can be seen that the pH of the extract obtained in Example 1 is higher than that of the extract produced from comparative tests. This increases the availability of nicotine in solution when used in an e-cigarette.

Similar results were observed when using Oriental or Burley starting cigarettes.

The various embodiments described herein are provided only to aid in understanding and teaching the claimed features. These embodiments are provided only as samples of representative embodiments, and are not exhaustive and/or exclusive. The advantages, embodiments, examples, functions, features, structures and/or other aspects described herein are not to be regarded as limitations on the scope of the invention defined by the claims or on an equivalent basis to the claims, and It is to be understood that other embodiments may be utilized and modifications may be made without departing from the scope of the disclosed invention. The various embodiments of the present invention may suitably include, consist of, or consist essentially of suitable combinations of the recited elements, elements, features, parts, steps, means, etc., other than those specifically described herein. can In addition, the present disclosure may cover other inventions that are not currently claimed but may be claimed in the future.

Claims (12)

As a method for producing a tobacco extract,
(a) contacting tobacco with an extraction solvent to extract tobacco components from tobacco with an extraction solvent, wherein the extraction solvent comprises a supercritical fluid;
(b) separating residual tobacco solids from the extraction solvent containing tobacco components;
(c) releasing the tobacco components from the extraction solvent by providing a capture solvent in a vessel and exposing the extraction solvent containing the tobacco components to conditions in the vessel such that the extraction solvent is subcritical; wherein the capture solvent dissolves the tobacco components released from the extraction solvent. The method of claim 1 , wherein the extraction solvent comprises carbon dioxide. The method of claim 2, during step (a),
The temperature is in the range of 308-473K,
A method in which the pressure is in the range of 8-85 MPa. The method of claim 1 wherein the capture solvent comprises an aerosol generating agent. 5. The method of claim 4, wherein the capture solvent comprises a polyol. 2. The method of claim 1, wherein the tobacco component comprises at least one of nicotine and tobacco flavor and flavoring. The method of claim 1 , further comprising providing a capture solvent containing dissolved tobacco components in a cartridge, wherein the cartridge is configured for use in a smoking article. Tobacco extract obtainable by the process according to claim 1 . A cartridge configured for use in a smoking article, said cartridge containing a tobacco extract according to claim 8 . A smoking article containing the tobacco extract according to claim 8 . Tobacco extract obtainable by the process according to any one of claims 1 to 7 for generating an inhalable aerosol. 12. The tobacco extract of claim 11 wherein the tobacco extract is used in a smoking article.