SMOKING COMPOSITION COMPRISING FLAVOUR PRECURSOR

Abstract

A smoking composition comprises an aerosol-forming substrate and a flavour precursor compound. Upon heating, the precursor compound releases a thiol-containing flavour compound or intermediate that enhances the flavour experience of the aerosol-forming substrate when used in a smoking article. The smoking article may include tobacco and may be configured to heat, but not combust, the tobacco.

Claims

1. (canceled)

2. A smoking article comprising: an aerosol forming substrate comprising tobacco; a heating element configured to heat, but not combust, the aerosol forming substrate; a flavour precursor compound added to the aerosol forming substrate, wherein the flavour precursor compound releases a thiol-containing flavour compound upon heating of the aerosol forming substrate by the heating element, wherein heating of the aerosol forming substrate and the flavour precursor compound results in the production of furfurylthiol.

3. A smoking article according to claim 2, wherein the flavour precursor compound is configured to release the flavour compound at a temperature of from about 200° C. to about 450° C.

4. A smoking article according to claim 3, further comprising nicotine or a source of nicotine.

5. A smoking article according to claim 2, further comprising nicotine or a source of nicotine.

Description

[0076] FIG. 1 is a schematic drawing of a smoking article in which a smoking composition is not combusted.

[0077] FIG. 2 is a schematic drawing of a smoking article that is heated by an electrical heat source when engaged with a device for consumption.

[0078] By way of example and with reference to FIG. 1, a schematic drawing of a smoking article 102 in which the smoking composition is not combusted is shown. As shown in FIG. 1, the smoking article 102 includes a combustible heat source 104, an aerosol-forming substrate 106, an elongate expansion chamber 108 and a mouthpiece 110 in abutting coaxial alignment, which are overwrapped in an outer wrapper of cigarette paper 112 of low air permeability.

[0079] The combustible heat-source 104 is a pyrolised porous carbon-based heat source. The combustible heat source 104 is cylindrical and comprises a central airflow channel 116 that extends longitudinally through the combustible heat source 104. A substantially air impermeable, heat resistant coating 114 of iron oxide is provided on the inner surface of the central airflow channel 116. The aerosol-forming substrate 106 is located immediately downstream of the combustible heat source 104 and comprises a cylindrical plug of homogenised tobacco material 118 comprising a flavor precursor compound and glycerine as aerosol former and circumscribed by filter plug wrap 120. The homogenized tobacco material 118 consists of longitudinally aligned filaments of extruded tobacco material.

[0080] A heat-conducting element 122 consisting of a tube of aluminum foil surrounds and is in contact with a rear portion of the combustible heat source 104 and an abutting front portion of the aerosol-generating substrate 106. As shown in FIG. 1, a rear portion of the aerosol-generating substrate 106 is not surrounded by the heat-conducting element 122.

[0081] The elongate expansion chamber 108 is located downstream of the aerosol-generating substrate 106 and comprises a cylindrical open-ended tube of cardboard 124. The mouthpiece 110 of the smoking article 102 is located downstream of the expansion chamber 108 and comprises a cylindrical plug of cellulose acetate tow 126 of very low filtration efficiency circumscribed by filter plug wrap 128. The mouthpiece 110 may be circumscribed by tipping paper (not shown). The dimensions of the smoking article 102 may be similar to a conventional cigarette.

[0082] In use, a user ignites the combustible carbon-based heat source 4 and then draws air through the central airflow channel 116 downstream towards the mouthpiece 110. The front portion of the aerosol-generating substrate 106 is heated primarily by conduction through the abutting non-combusting rear portion of the combustible heat source 104 and the heat-conducting element 122. The drawn air is heated as it passes through the central airflow channel 116 and then heats the aerosol-forming substrate 106 by convection. The heating of the aerosol-forming substrate 106 releases volatile and semi-volatile compounds, including the disassociated flavor compound, and glycerine from the aerosol forming substrate 118, which are entrained in the heated drawn air as it flows through the aerosol-forming substrate.

[0083] The heated air and entrained compounds pass downstream through the expansion chamber 108, cool and condense to form an aerosol that passes through the mouthpiece into the mouth of the user (at about ambient temperature).

[0084] To make the smoking article 102, a rectangular piece of the heat-conducting element 122 is glued to cigarette paper 112. The heat source 104, the plug of the aerosol-forming substrate 106 and the expansion chamber 108 are suitably aligned and positioned on the cigarette paper 112 with the attached heat-conducting element 122. The cigarette paper 112 with the attached heat-conducting element 122 is wrapped around the rear portion of the heat source 104, the aerosol-generating substrate 106 and the expansion chamber 108 and glued. The mouthpiece 110 is attached to the open end of the expansion chamber using known filter combining technology.

[0085] In another example of a heated smoking article, the smoking composition comprising the flavor precursor compound is brought into direct contact with a heat source that is not combusted, such as an electrical heat source. FIG. 2 shows a smoking article that is heated by an electrical heat source when engaged with a device for consumption. The smoking article 101 comprises a front-plug 103, an aerosol-forming substrate 111, a hollow cellulose acetate tube 109, a transfer section 107, and a mouthpiece filter 105. These five elements are arranged sequentially and in coaxial alignment and are assembled by a cigarette paper 115 to form a rod. The rod has a mouth-end, which a user inserts into his or her mouth during use, and a distal end located at the opposite end of the rod to the mouth end. When assembled, the rod is 52 mm long and has a diameter of 7.2 mm. The front-plug 103 is a cylindrical portion of cellulose acetate tow. The aerosol-forming substrate 111 is located downstream of the front-plug 103 and comprises a bundle of crimped cast-leaf tobacco wrapped in a filter paper. The cast-leaf tobacco includes additives, including glycerine as an aerosol former. The tube 109 is located immediately downstream of the aerosol-forming substrate 111 and is formed from cellulose acetate. The transfer section 107 allows volatile substances including the flavor compound released from the aerosol-forming substrate 111 to pass along the rod towards the mouth end. The volatile substances may cool within the transfer section 107 to form an aerosol. The mouthpiece filter 105 is a conventional mouthpiece filter formed from cellulose acetate tow. The elements identified above are assembled by being tightly wrapped within a cigarette paper 115.

[0086] The aerosol-generating device 119 comprises a sheath 121 for receiving the smoking article 101 for consumption. A heating element 113 is located within the sheath 121 and positioned to engage with the distal end of the smoking article 101. The heating element 113 is shaped in the form of a blade terminating in a point. As the smoking article 101 is pushed into the sheath the point of the heating element 113 engages first with the front-plug 103 and then penetrates into the aerosol-forming substrate 111. When the smoking article 101 is properly engaged with the aerosol-generating device 119, the heating element 113 is located within the aerosol-forming substrate 111. Heat generated by the heating element 113 is transferred by conduction and convection to the aerosol-forming substrate 111 which comprises the flavor precursor compound. An insulating collar 117 may surround a portion of the heating element 113 that is in contact with and protect the front-plug 103 from burning or melting. Of course, it will be understood that the smoking articles described with regard to FIG. 1 and FIG. 2 are just two examples of a smoking article that may employ a smoking composition comprising a flavor precursor compound as described herein. It will be further understood that methods for making a smoking article having a smoking composition that includes a flavor precursor compound other than those described in connection with FIG. 1 and FIG. 2 may be employed.

[0087] Any suitable method for making a smoking article having a smoking composition that includes a flavor precursor compound may be employed. In general, a method for making a smoking article having a smoking composition that includes a flavor precursor compound includes adding or incorporating the flavor precursor compound or a flavor delivery composition into a smoking composition, such as tobacco or other substrate; and incorporating the smoking composition into a smoking article.

[0088] In general and as described herein, a method for enhancing flavor of a smoking composition comprises adding a flavor precursor compound, optionally encapsulated in a delivery system, to the smoking composition. The flavor precursor compound releases or dissociates a flavor compound or intermediate upon heating. As used herein “release” and “dissociate” are used interchangeably. The heating of the flavor precursor compound occurs when a smoking article is used (combusted or heated) by a smoker.

[0089] All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein.

[0090] As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise.

[0091] As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

[0092] As used herein, “have”, “having”, “include”, “including”, “comprise”, “comprising” or the like are used in their open ended sense, and generally mean “including, but not limited to”. It will be understood that “consisting essentially of”, “consisting of”, and the like are subsumed in “comprising,” and the like.

[0093] Non-limiting examples illustrating certain aspects of the compounds, compositions, processes and articles described in this disclosure are provided below.

EXAMPLES

Example 1

[0094] A variety of non-volatile sulfur compounds, as shown in table 1, are screened by (ATD) GC-MS on a cellulose filter to determine whether and how much hydrogen sulfide and methanethiol they release upon heating.

[0095] The compounds are also added to non-combusted smoking articles to assess the change in sensory attributes of such compounds during aerosolisation of such articles in the presence and absence of the compounds.

[0096] Certain of the non-volatile sulfur compounds are also applied to a blended tobacco by syringe injection and used for non-combusted smoking substrates. The tobacco with the non-volatile sulfur compounds is formed into sticks and equilibrated for at least 12 hours prior to assessment.

[0097] The ortho-nasal impact of the selected compounds is evaluated in different concentrations on global aroma by usage of the smoke simulator in pushing mode. Selected compounds are then selected for sensory testing.

TABLE-US-00001 TABLE 1 Non-volatile sulfur compounds non-volatile thiol-containing compounds CAS No. category Cysteine 3374-33-9 amino acid Cystin 56-89-3 amino acid derivate Glutathione 70-18-8 natural antioxidant in cells Methionine 59-51-8 amino acid DL-Methionine methylsulfonium 582174 amino acid derivate chloride N-Acetyl L-cysteine 616-91-1 amino acid derivate S-methyl L-cysteine 1187-84-4 amino acid derivate DL-Homocysteine 454-29-5 amino acid derivate N-Acetyl L-methionine 65-82-7 amino acid derivate Farnesyl-Met-Ome 218962-72-2 amino acid derivate Egg albumin 9006-59-1 sulfur rich protein 2-Hydroxy-4-(methylthio)butyric 922-50-9 non-amino acid sulfur acid Ca salt source

[0098] Aqueous solutions are prepared according to table 2. Additionally 1:10 and 1:100 dilutions are prepared for validation.

TABLE-US-00002 TABLE 2 Stock solution preparation of tested compounds non-volatile sulfur compounds weight (g) mL of H2O Cysteine 1.00 10 Cystin n/a n/a Glutathione 1.00 10 Methionine 0.50 20 DL-Methionine methylsulfonium chloride 1.08 10 N-Acetyl L-cysteine 1.50 10 S-methyl L-cysteine 0.98 20 DL-Homocysteine 0.50 10 N-Acetyl L-methionine 1.91 10 Farnesyl-Met-Ome 1 μL 20 μL Egg albumin 0.50 10 2-Hydroxy-4-(methylthio)butyric acid Ca salt 1.00 20

[0099] ATD-GC-MS analyses are performed using following instrumental set-up:

TABLE-US-00003 TABLE 3 ATD-GC-MS instrumentation Instrument Details Injector Perkin Elmer Thermal Desorber Turbo Matrix 350 Gas chromatograph Agilent 7890A GC Column 60 m × 0.25 μm, FFAP Mass chromatograph Agilent 5975C

TABLE-US-00004 TABLE 4 ATD-GC-MS parameters ATD parameters Value tube temperature 250° C. trap temperature −40° C. temperature gradient 99° C. per second to 275° C. desorption time 5 min N.sub.2 pressure 170 kPa; constant

[0100] Of each compound solution (stock, 1:10, 1:100) 20 μL are spiked on a pre-equilibrated Cambridge pad piece which is then inserted into glass tube. Tubes are ortho-nasally assessed after thermal desorption and detected aroma notes determined. The results are given in Table 5.

TABLE-US-00005 TABLE 5 Flavour Evaluation non-volatile sulfur compounds comments and ortho-nasal evaluation Cysteine fresh tubes (250° C. heated) gave burnt phenolic roasty impression with weak sulfury meaty note Glutathione fresh tubes (350° C. heated) gave only weak roasty impression Methionine fresh tube (350° C. heated) smelled cooked potato and meaty-like N-Acetyl L-methionine Methanethiol note stronger than hydrogen sulfide note Farnesyl-Met-Ome cooked potato-like Egg albumin Methanethiol and hydrogen sulphide balanced out 2-Hydroxy-4- fresh tubes (250° C. heated) smelled cooked potato-like with a sulfury (methylthio)butyric acid roasty aspect Ca salt DL-Methionine green, cabbage, fishy, sulfury green methylsulfonium chloride N-Acetyl-Cysteine popcorn, meaty, roasty DL-Homocysteine roasty, very weak S-Methyl-L-Cysteine cabbage, sulfury

[0101] The results indicate that there are mainly two families of compounds, the first generating predominantly hydrogen sulphide (H.sub.2S) and the second generating predominantly methanethiol (MSH). The exception is egg albumin for which the generation seems to be similar.

[0102] The tubes of those candidates generating mostly H.sub.2S were ortho-nasally evaluated after heating as being sulfury, roasty or burnt. H.sub.2S could not be directly detected. In contrast the methanethiol generating compounds all were judged having a potato-like aroma, indicating the presence of methional as side product.

Example 2

[0103] Orthonasal & smoking evaluation of selected non-volatile sulfur compounds is performed using a smoke simulator in pushing mode. The following prototypes are tested:

TABLE-US-00006 TABLE 6 Prototypes to be tested concentration concentration non-volatile sulfur spiked in mg spiked in mg compounds (concept A) (concept B) Cysteine 1.82 0.182 Glutathione 1.75 0.175 Methionine 0.47 0.047 2-Hydroxy-4- 0.94 0.094 (methylthio)butyric acid Ca salt DL-Methionine 1.00 0.10 methylsulfonium chloride S-Methyl-L-Cysteine 2.07 0.20

[0104] Testing is performed as follows. The smoking regime is Health Canada. The power setting of smoke simulator is 54 W. Smoking evaluation is performed for concepts showing preference in ortho-nasal evaluation. Smoking evaluation is performed by comparison of untreated blend versus treated concept

[0105] For submission to sensory testing in Expert Panel only Cysteine and Glutathione were selected. For Glutathione Concept B and Cysteine Concept B was chosen.

TABLE-US-00007 TABLE 7 Observations recorded during the experimental run Thiol-containing compound Concept Panel description Cysteine A sulfury, cold smoke, less off-notes B sulfury, cold smoke, less off-notes Glutathione A sulfury, cold smoke, less off-notes B sulfury, cold smoke, less off-notes Methionine A cooked potato and sulfury vegetable are dominating B cooked potato, sulfury vegetable, less off-notes 2-Hydroxy-4- A increased sulfury notes; direction sulfury green & smoked ham (methylthio) butyric B increased sulfury smoked perception with less off-notes acid Ca salt DL-Methionine A cooked potato, cabbage notes, untypical aroma methylsulfonium B no significant difference chloride S-Methyl-L-Cysteine A increase of sulfury notes; green, bell pepper-like & meaty notes B close to reference with increased hay-like, greenish notes

[0106] The addition of sulfur containing compounds, especially with free thiol groups, improves the flavor perception of non-combustible products and addresses issues, such as off-notes, complexity and mouth fullness. In particular, addition of the thiol-containing precursors Cysteine and Glutathione contributes positively to the global flavor of aerosols formed upon heating by adding smokiness, mouth fullness, harshness, bitterness and complexity.

[0107] In summary the addition of sulfur containing precursors was shown to have a positive effect on the overall sensory perception of prototypes by increasing smoky dark attributes, reducing non-combustible product off-notes and increasing mouth and throat sensations, like bitterness and mouth fullness.