Wax encapsulated zeolite flavour delivery system for tobacco

Abstract

A flavour delivery system for tobacco includes a flavour material entrained in a zeolite material and forming a core and a wax material encapsulating the core.

Claims

1. A flavour delivery system for tobacco comprising: a flavour material entrained in a zeolite material and forming a core comprising the flavour material and the zeolite, a wax material applied onto the core in molten form and surrounding the core and forming an encapsulated flavour particle, the core comprising from 1% to 50% of a total weight of the encapsulated flavour particle, wherein the encapsulated flavour particle has a particle size in a range from about 5 micrometres to about 80 micrometres, and the zeolite material has a particle size in a range from about 1 micrometer to about 20 micrometers.

2. A flavour delivery system according to claim 1, wherein the wax material has a melting point of about 100 degrees centigrade or greater.

3. A flavour delivery system according to claim 2, wherein the zeolite material is hydrophobic.

4. A flavour delivery system according to claim 1, wherein the zeolite material is hydrophobic.

5. A flavour delivery system according to claim 1, wherein the flavour material is a hydrophobic liquid.

6. A smoking composition comprising tobacco material and the flavour delivery system according to claim 1.

7. A smoking composition according to claim 6, wherein the tobacco material comprises homogenized tobacco.

8. A smoking composition according to claim 6, wherein the tobacco material comprises cast leaf tobacco.

9. A smoking composition according to claim 6, wherein at least a portion of the wax material is melted off the core and is dispersed within the tobacco material.

10. A smoking article comprising an aerosol forming substrate comprising the smoking composition of claim 6.

11. A smoking article comprising an aerosol forming substrate comprising the smoking composition of claim 9.

12. A method of forming a smoking composition comprising: combining tobacco material with the flavour delivery system according to claim 1 to form a tobacco mixture; and heating the tobacco mixture to form the smoking composition.

13. A method of forming a smoking composition according to claim 12, wherein the tobacco material comprises homogenized tobacco and water and the heating step removes at least a portion of the water from the tobacco mixture to form the smoking composition.

14. A method of forming a smoking composition according to claim 13, wherein the heating step melts at least a portion of the wax material.

15. A method of forming a smoking composition according to claim 12, wherein the heating step melts at least a portion of the wax material.

16. A method of forming a smoking composition according to claim 12, wherein the heating step does not melt the wax material.

Description

(1) FIG. 1, is a schematic diagram of an illustrative flavour delivery system 10 or encapsulated flavour core. The schematic drawing is not necessarily to scale and is presented for purposes of illustration and not limitation. The drawing depicts one or more aspects described in this disclosure. However, it will be understood that other aspects not depicted in the drawing fall within the scope and spirit of this disclosure.

(2) Referring now to FIG. 1, the flavour delivery system 10 includes a flavour material 12 entrained in a zeolite material 14 forming a core 11 and a wax material 16 encapsulating the core 11.

(3) The core 11 has a particle size or largest lateral dimension D.sub.1. The flavour delivery system 10 has a particle size or largest lateral dimension D.sub.2.

(4) Non-limiting examples illustrating flavour delivery system as described above and tobacco substrates and smoking articles having such flavour delivery systems are described below.

EXAMPLES

(5) A variety of wax materials were evaluated as described below for suitability in the flavour delivery system as described above.

(6) Flash and fire points for selected wax excipients were determined according ISO 2592 (Cleveland open cup method). The flash point is the lowest temperature at which a flame will ignite the vapors of the heated excipient, while the fire point is the lowest temperature when the vapors ignite and burn for at least 2 seconds. It will be appreciated that the melting point in practice for the wax material will depend on for example any impurities or other components in the wax, as well as the pressure. Results of this testing (at ambient pressure) is reported in Table 1.

(7) TABLE-US-00001 TABLE 1 Melt- Fire Flash ing point point point Wax Type (° C.) (° C.) Supplier (° C.) Rice bran Natural wax 299 333 Kahlwax/  79-85 (Kahlwax Kahlwax   2811)   Sunflower Natural wax 305 335 Kahlwax/  74-80 wax Kahlwax   (Kahlwax   6607)   Carnauba Natural wax 315 345 Kahlwax/  82-86 wax Kahlwax   (Kahlwax   2442L)   Candelilla Natural wax 269 299 Kahlwax/  68-73 wax Kahlwax   (Kahlwax   2039)   Cutina wax Hard Fat 325 341 CareChemicals  83-88 Licowax Polyethylene 249 >309 Clariant/Parka 101-106 521 PED wax d.o.o. Ceridust Polyolefin 297 329 Clariant/Parka 108-116 2051 wax d.o.o. Ceridust Polyethylene 263 >303 Clariant/Parka 125-130 3610 wax d.o.o. Deurex MX Polypropylene 277 329 Deurex/Deurex 110-118 9820 wax Deurex ME Polyethylene 261 >321 Deurex/Deurex 122-130 1620 wax Deurex MT Fischer- 295 339 Deurex/Deurex 112-120 9120 Tropsch wax Sasolwax Fischer- 287 327 Sasolwax/HDS 112 H1 Tropsch wax Chemie Sasolwax Fischer- na Na Sasolwax/HDS 117 H105 Tropsch wax Chemie Vestowax Fischer- 267 295 Evonik/Evonik 102-110 EH100 Tropsch wax Vestowax Fischer- 310 333 Evonik/Evonik 108-114 SH105 Tropsch wax PEG 6000 Polymer 233 >259 Merck  55-60 PEG 35000 Polymer 259 >319 Merck  60-65 Ceridust Polypropylene 271 319 Cladant/Parka 142-148 6050M wax d.o.o. Revel A Hard fat 319 347 Loders Croklaan —

(8) A sensory analysis of wax materials is determined using the descriptive criterion “overall sensory neutrality” to indicate intensity differences. As sensory and psychological fatigue sets in after 7-8 samples, a balanced incomplete block design (BiB) (ISO 29842) is selected for the ranking test (ISO 8587). Assessors receive per session five samples in random order and are asked to rank the samples according to the criterion. Four sessions are performed in order to achieve an adequate level of precision. Results of this BiB ranking are reported in Table 2.

(9) TABLE-US-00002 TABLE 2 BiB Ranking rank sum 15D = 13 0 Tixosil 45 A I Deurex MT 9120 37 A B Sasolwax H1 35 A B C Ceridust 3610 33 A B C Ceridust 2051 33 A B C Cutina HR 33 A B C Vestowax EH 100 32  B C II Vestowax SH 105 28  B C D Sasolwax H105 27  B C D E Kahlwax 2811 (Rice Bran) 27  B C D E III Kahlwax 24421 (Carnauba) 25  B C D E F Kahlwax 2039 (Candelilla) 23   C D E F IV Deurex ME 1620 18    D E F Deurex MX 9820 17    D E F Licowax PED 521 GR 15     E F Kahlwax 6607 (Sunflower) 14      F

(10) A number of flavour delivery systems are formed by entraining a flavour in a zeolite material via supercritical carbon dioxide entrainment. Thus, the solubility of various flavourants in supercritical carbon dioxide is determined.

(11) Flavour Phase Equilibra in CO.sub.2

(12) Phase behaviour observations are performed in a 62 mL high pressure view cell. Maximum operating pressure and temperature are 700 bar and 200° C. This view cell is equipped with a propeller stirrer enabling turbulent mixing. The view cell is heated by means of an electrical jacket connected to a thermoregulation unit (Eurotherm 2216e). The temperature inside the cell is measured by a thermocouple Ni—Cr (GTH 1150 Greisinger electronic, accuracy ±1.0° C.). The pressure is measured by a digital manometer (Wika, accuracy 0.1 bar), Liquid CO.sub.2 is charged to the view cell by means of a high pressure pump (max. Pressure 600 bar).

(13) Phase equilibria observations are performed for the flavourant guaiacol in carbon dioxide in the pressure range from 50 to 500 bar at temperatures 40° C., 60° C. and 80° C. The 62 mL high pressure view cell was filled with 20 mL of guaiacol at room conditions. The operating conditions employed for observation of phase behavior are shown in FIG. 2, represented as circles.

(14) Phase equilibria observations are performed for the flavourant 3-methylbutanan in carbon dioxide. The mixture of 3-methylbutanal and CO.sub.2 is first brought into a heterogeneous state (two phase region). The temperature is kept constant and the pressure slowly varied by changing the volume of the cell until the second phase disappeared. Phase transitions are determined visually. The phase transition line is constructed for two different volume ratios of CO.sub.2—3-methylbutanal regarding the total maximum volume of the cell: 5 and 2 (v/v) and is shown in FIG. 3. It is observed in FIG. 3 that the solubility of CO2 in the liquid phase is relatively high, even at moderate pressures, which is indicated by the increase of liquid level in the binary system. There is a complete miscibility between CO.sub.2 and 3-methylbutanal above the phase transition line—single phase region. The phase transition line for the binary system with higher ratio of CO.sub.2:3-methylbutanal (R=5) lies slightly higher in comparison with ratio of 2.

(15) Phase equilibria observations are performed for the flavourant “PMI Key” flavour mixture in carbon dioxide. The PMI Key flavour mixture is provided in the following Table 3 below.

(16) TABLE-US-00003 TABLE 3 compound odor quality MW in g/mol guajacol smoky 124.14 3-ethylphenol phenolic, leather 122.16 dimethyl trisulfide cabbage-like, sulfury 126.26 2-ethyl-3,6-dimethylpyrazine earthy 136.20 4-isopropylphenol phenolic, plastic 136.19 2-furfurylthiol coffee-like 114.17

(17) Phase behavior observations of the system PMI Key flavour mixture/CO.sub.2 in the pressure range from 50 to 250 bar within temperature range between 40° C. and 130° C. is performed. The mixture of PMI key flavour and CO.sub.2 is first brought into a heterogeneous state (two phase region). The temperature is kept constant and the pressure is slowly increased by changing the volume of the cell until the second phase disappeared. Phase transitions are determined visually. The phase transition line is constructed for ratio of CO.sub.2:Flavour mixture key=5 (v/v) regarding the total maximum volume of the cell. It is observed that the phase transition line follows a linear trend. Results are presented in FIG. 4.

(18) Zeolite Screening

(19) Two different zeolite materials are used to cover the range of polarity of commercially available zeolites. As representative for hydrophilic zeolites the following materials were screened: 13X & 4A (SILKEM, Slovenia). As representative for hydrophobic zeolites the following materials were screened: UK8 & UZ8 (Chemiewerk, Bad Köstritz, Germany). Incorporation of the zeolites 13X and UZ8 into a cast leaf process at 3% wt and formed into a tobacco substrate are analysed for silicium in the aerosol generated by the tobacco substrate. The results show that silica could not be determined in the aerosol.

(20) Flavour Release from Zeolite Core

(21) To evaluate whether the silica based material (zeolites) are capable of retaining and liberating flavour ingredients, zeolite materials loaded with flavour are evaluated for flavour loss by thermogravimetric analyses. FIG. 5 shows the results for the flavour release of different zeolites which may be used as core material. The flavour retention of hydrophilic zeolites is in a range of 7.7 to 8.2% whereas flavour retention of hydrophobic zeolites show a retention of flavour ingredients up to 23%. The release temperatures indicate that a core material is required to protect the flavour ingredients from unintended flavour release during the cast leaf process.

(22) Evaluation of Core Shell Materials

(23) The following Table 4 indicates the arrangement of zeolite material (UZ8) loaded with a flavourant and encapsulated with a wax material (Ceridust 3610). The flavour delivery system was formed by entraining the flavour in the zeolite to from the core and then spray chilling the core with a wax material (Ceridust 3610) to form the encapsulated core or flavour delivery system. The core accounted for about 10% wt of the total weight of the first seven delivery systems. The last example had a 20% wt core loading in the shell material.

(24) TABLE-US-00004 TABLE 4 Shell material core material Core load Ceridust 3610 UZ8 loaded with 3-Methylbutanal 10% Ceridust 3610 UZ8 loaded with Furfurylthiol 10% Ceridust 3610 UZ8 loaded with Dimethyltrisulfide 10% Ceridust 3610 UZ8 loaded with 2-Ethyl-3,5(6)- 10% dimethylpyrazine Ceridust 3610 UZ8 loaded with Guajacol, 3-Ethylphenol, 10% 4-isopropylphenol Ceridust 3610 UZ8 loaded with Standard Key 10% Ceridust 3610 UZ8 loaded with Optimized Key 10% Ceridust 3610 UZ8 loaded with Optimized Key 20%

(25) These samples are then analyzed for particle size distribution, bulk density and morphology.

(26) The particle size distribution is measured by laser diffraction method with the Malvern Mastersizer 2000. The liquid dispersion unit “Hydro MU” is used to measure the particles dispersed in ethanol. After the samples are dispersed in ethanol the ultrasonic bath is turned on for a period of 3 minutes to break the agglomerates. After 1 minute the measurement is initiated. All samples are measured twice and the average values are reported. The interpretation of the data is done according to the theory of Fraunhofer.

(27) The Mastersizer breaks the agglomerates by using an ultrasonic batch prior to the particle size measurement; the particle size measured by laser diffraction method differs from the expected particle size of the sieved fractions. By sieving the samples, the agglomerates are not destroyed and the sieved fractions in fact consist of agglomerates rather than fractions of single particles.

(28) FIG. 6 and FIG. 7 report the particle size distributions of the core-shell samples of examples in Table 2 produced by the spray chilling process described above. Two particle size ranges (63-125 μm and 125-250 μm) are collected and tested for bulk density and flavour release below.

(29) The bulk density of the core-shell samples of examples in Table 2 is measured in accordance to DIN ISO 697. In FIG. 8 and FIG. 9 the bulk densities are reported.

(30) FIG. 10 shows a scanning electron microscope (SEM) pictures of pure spray chilled Ceridust C3610. FIG. 11 shows a scanning electron microscope (SEM) picture of pure unloaded zeolite UZ8. FIG. 12 shows a scanning electron microscope (SEM) picture of a flavour delivery system of Ceridust C3610+10% unloaded zeolite.

(31) As illustrated in FIGS. 10-12 the shape of the pure sprayed Ceridust 3610 particles and the shape of the particles with the encapsulated zeolites are spherical and the surface is nearly smooth. In contrary to this, the particles of the pure unloaded zeolites are angular. In the bulk of the particles of the sprayed suspension of Ceridust 3610 and unloaded zeolites nearly no particle can be found which is angular, what an indicator is, that most of the zeolites are encapsulated in Ceridust 3610.

(32) Flavour Release

(33) The flavour release of the flavour delivery system described herein was then evaluated. A flavour delivery system described herein that was formed by impregnation of zeolites and subsequent spray chilling. The flavour delivery system was added to cast leaf slurry prior to cast leaf tobacco substrate generation at a level of 3% (w/w). The cast leaf was generated according to a standard cast-leaf procedure involving a drying step at approximately 100° C. No special observations were made during cast leaf manufacturing, indicating no to low flavour losses. Using the generated cast leaf, consumables (tobacco sticks) were manufactured to be used in the aerosol generating substrate.

(34) Flavour release analyses were performed by the Health Canada Intense Smoking Regime. The results are illustrated in FIG. 13.