HYDROPHOBIC CAPSULE

Abstract

A capsule for use in a smoking article includes a liquid sensory enhancing material; and a shell surrounding the liquid sensory enhancing material. The shell has an outer surface rendered hydrophobic by hydrophobic groups covalently bond to the outer surface of the shell. The shell may be rendered hydrophobic by reacting hydroxyl groups at outer surface of the shell with fatty acid halides to covalently attach fatty acid moieties to the surface of the capsule.

Claims

1. A capsule for use in a smoking article, the capsule comprising: a liquid sensory enhancing material; and a shell surrounding the liquid sensory enhancing material, the shell having an outer surface rendered hydrophobic by hydrophobic groups covalently bond to the outer surface of the shell.

2. A capsule according to claim 1, wherein the hydrophobic groups comprise fatty acid moieties or fatty acid esters.

3. A capsule according to claim 2, wherein the fatty acids or fatty acid esters comprise aliphatic chains that have 16 to 24 carbon atoms (C.sub.16-C.sub.24).

4. A capsule according to claim 1, wherein the hydrophobic group is covalently bonded to the surface of the shell by reacting a fatty acid halide with a pendant hydroxyl group on the surface of the shell to form a fatty acid ester moiety.

5. A capsule according to claim 4, wherein the covalent bonding is between a hydroxyl group of a polysaccharide and the fatty acid halide.

6. A capsule according to claim 4, wherein the fatty acid halide is a fatty acid chloride.

7. A capsule according to claim 6, wherein the fatty acid chloride is palmitoyl chloride, stearoyl chloride, behenoyl chloride, or a mixture of palmitoyl chloride and stearoyl chloride.

8. A capsule according to claim 1, wherein the shell of the capsule comprises gelatin.

9-12. (canceled)

13. A method for manufacturing a capsule comprising a sensory enhancing material and a shell surrounding the sensory enhancing material, the shell having a hydrophobic outer surface, the method comprising: reacting a reactive group on an outer surface of the shell with a fatty acid halide.

14. A method according to claim 13, wherein the reactive group on the surface of the capsule comprises a hydroxyl moiety.

15. A method according to claim 14, wherein the fatty acid halide reacts with the hydroxyl moiety to form a fatty acid ester moiety.

Description

[0067] The invention will be further described, by way of example only, with reference to the accompanying drawings in which

[0068] FIG. 1 is a schematic drawing of a perspective view of an embodiment of a smoking article, in this case a cigarette, with an unrolled wrapper;

[0069] FIG. 2 is a schematic cross-sectional diagram of an embodiment of a smoking article comprising a mouthpiece that includes a capsule; and

[0070] FIG. 3 is a schematic drawing illustrating an embodiment of reaction to graft a hydrophobic moiety to a hydrophilic surface.

[0071] The smoking article 100 depicted in FIG. 1 includes an aerosol forming substrate in the form of a generally cylindrical tobacco rod 101 and a mouthpiece in the form of a generally cylindrical filter 103. The tobacco rod 101 and filter 103 are axially aligned in an end-to-end relationship, preferably abutting one another. The tobacco rod 101 includes an outer wrapper 105 circumscribing the smoking material. The tobacco is preferably a shredded tobacco or tobacco cut filler. The filter 103 includes a filter wrapper (not shown) circumscribing the filter material. The tobacco rod 101 has an upstream, lit end 109 and a downstream end 111. The filter 103 has an upstream end 113 and a downstream, mouth end 115. The upstream end 113 of the filter 103 is adjacent the downstream end 111 of the tobacco rod 101. A breakable capsule 120 containing a liquid flavorant is disposed in a cavity of the filter 103.

[0072] The filter 103 is attached to the tobacco rod 101 by tipping material 117 which circumscribes the entire length of the filter 103 and an adjacent region of the tobacco rod 101. The tipping material 117 is shown partially removed from the smoking article in FIG. 1, for clarity. In this embodiment, the tipping material 117 also includes a circumferential row of perforations 123. The perforations 123 are provided for ventilation of the mainstream smoke.

[0073] FIG. 2 illustrates a smoking article 10 according to a preferred embodiment. The smoking article 10 comprises four elements arranged in coaxial alignment: an aerosol-forming substrate 20, a support element 30, an aerosol-cooling element 40, and a mouthpiece 50. These four elements are arranged sequentially and are circumscribed by an outer wrapper 60 to form the smoking article 10. The smoking article 10 has a proximal or mouth end 70, which a user inserts into his or her mouth during use, and a distal end 80 located at the opposite end of the smoking article 10 to the mouth end 70. A breakable capsule 120 containing a liquid flavorant is disposed in the mouthpiece 50.

[0074] In use air is drawn through the smoking article 10 by a user from the distal end 80 to the mouth end 70. The distal end 80 of the smoking article may also be described as the upstream end of the smoking article 10 and the mouth end 70 of the smoking article 10 may also be described as the downstream end of the smoking article 10. Elements of the smoking article 10 located between the mouth end 70 and the distal end 80 may be described as being upstream of the mouth end 70 or, alternatively, downstream of the distal end 80.

[0075] The aerosol-forming substrate 20 is located at the extreme distal or upstream end of the smoking article 10. In the embodiment illustrated in FIG. 2, aerosol-forming substrate 20 comprises a gathered sheet of crimped homogenised tobacco material circumscribed by a wrapper. The crimped sheet of homogenised tobacco material comprises comprising glycerine as an aerosol-former.

[0076] The support element 30 is located immediately downstream of the aerosol-forming substrate 20 and abuts the aerosol-forming substrate 20. In the embodiment shown in FIG. 2, the support element is a hollow cellulose acetate tube. The support element 30 locates the aerosol-forming substrate 20 at the extreme distal end 80 of the smoking article 10 so that it can be penetrated by a heating element of an aerosol-generating device. As described further below, the support element 30 acts to prevent the aerosol-forming substrate 20 from being forced downstream within the smoking article 10 towards the aerosol-cooling element 40 when a heating element of an aerosol-generating device is inserted into the aerosol-forming substrate 20. The support element 30 also acts as a spacer to space the aerosol-cooling element 40 of the smoking article 10 from the aerosol-forming substrate 20.

[0077] The aerosol-cooling element 40 is located immediately downstream of the support element 30 and abuts the support element 30. In use, volatile substances released from the aerosol-forming substrate 20 pass along the aerosol-cooling element 40 towards the mouth end 70 of the smoking article 10. The volatile substances may cool within the aerosol-cooling element 40 to form an aerosol that is inhaled by the user. In the embodiment illustrated in FIG. 2, the aerosol-cooling element comprises a crimped and gathered sheet of polylactic acid circumscribed by a wrapper 90. The crimped and gathered sheet of polylactic acid defines a plurality of longitudinal channels that extend along the length of the aerosol-cooling element 40.

[0078] The mouthpiece 50 is located immediately downstream of the aerosol-cooling element 40 and abuts the aerosol-cooling element 40. In the embodiment illustrated in FIG. 2, the mouthpiece 50 comprises a conventional filter material, such as cellulose acetate tow filter of low filtration efficiency.

[0079] A distal end portion of the outer wrapper 60 of the smoking article 10 may circumscribed by a band of tipping paper (not shown).

[0080] The smoking article 10 illustrated in FIG. 2 is designed to engage with an aerosol-generating device comprising a heating element in order to be consumed by a user. In use, the heating element of the aerosol-generating device heats the aerosol-forming substrate 20 of the smoking article 10 to a sufficient temperature to form an aerosol, which is drawn downstream through the aerosol-generating article 10 and inhaled by the user. The user may squeeze the mouthpiece 50 to cause the capsule 120 to break and release flavorant at any desired time during consumption of the article 10. The flavorant may be entrained in air carrying the aerosol and may be inhaled by the user along with the aerosol.

[0081] An example of a reaction to convert a hydrophilic surface 200 of a capsule to a hydrophobic surface 230 is shown in FIG. 3. The hydrophilic surface 200 includes pendant hydroxyl moieties 210 in the illustrated embodiment. A fatty acid chloride (RCOCl) 220 hydrophobic reagent may be reacted with the pendant hydroxy moiety 210 to produce a hydrophobic surface 230 having a pendant fatty acid moiety 240. Hydrochloric acid (HCl) 250 is a by-product of the reaction.

EXAMPLES

Example 1: Initial Proof of Concept

[0082] The effectiveness of hydrophobic treatment of a surface of a capsule was tested.

[0083] Capsules containing a menthol core and a shell composed mainly of gelatin were obtained from V. Mane Fils (France) and immersed in a solution containing palmitic acid chloride, a C.sub.16 fatty acid chloride, dissolved in petroleum ether (a nonprotic polar solvent). The capsules were allowed to dry in air after a brief immersion, and were then placed under an oven at 80-100 C for 2-8 minutes.

[0084] An untreated (as obtained by V. Mane Fils) and a hydrophobic-treated capsule were placed on a flat plane. On each of the surface of the hydrophobic-treated and the untreated capsule was placed a drop of water. A photograph (FIG. 4) of the capsules was taken a few minutes after the drops of water were placed on the capsules. In FIG. 4, the untreated capsule is on the left and the hydrophobic-treated capsule is shown on the right. The thickness of the wall of the untreated capsule increased from 50-100 micrometers to several fold thicker. The hydrophobic-treated capsule did not swell and the water drop maintained its overall original shape on the flat plane after a few minutes.

[0085] As evident from FIG. 4, the hydrophobic treatment of the capsule resulted in a different response to water. The treatment was effective in reducing the amount of water absorbed by the treated capsule relative to the untreated capsule.

Example 2: Additional Trials

I. Materials and Methods

[0086] A. C.sub.16 Fatty Acid Chloride Grafting

[0087] Spherical capsules with a shell comprising gelatin and a menthol-containing core [V. Mane Fils (France)] having a diameter of about 2 mm to about 3 mm (menthol) (“Menthol capsules”) and Viscopearl (roughly spherical objects made of viscose and having a diameter of about 1 mm (Rengo) were grafted with palmitic acid chloride, a C.sub.16 fatty acid chloride (C.sub.16 FAC), using three grafting techniques to determine which grafting techniques may work well to produce capsules with a hydrophobic shell. The grafting reacts the FACs with hydroxyl groups present on the surface of the shells of the capsules to covalently bond the fatty acid to the shell. The by-product of the reaction is hydrochloric acid, which is evacuated.

[0088] The three grafting techniques employed are outlined below:

[0089] 1. Oven

[0090] A reagent mix solution was prepared by introducing the C.sub.16 FAC (2% by weight) in a solvent (petroleum ether, 98%). The capsules were immersed in the reagent mix solution for a few minutes and removed from the reagent mix solution. The residual solvent was evaporated from the capsules at room temperature for a few minutes. The capsules were then placed in an oven, which was kept under nitrogen flux at 850 mbar pressure and at a temperature of 150° C. for the time indicated below in Table 1, or kept under atmospheric conditions at a temperature of 150° C. for the time indicated below in Table 1.

[0091] 2. Heat Gun

[0092] A reagent mix solution was prepared by introducing the C.sub.16 FAC (2% by weight) in a solvent (petroleum ether, 98%). The capsules were immersed in the reagent mix solution for a few minutes and removed from the reagent mix solution. The residual solvent was evaporated from the capsules at room temperature for a few minutes. The C.sub.16 FAC was grafted to the capsule surface by directing a heat gun set at a temperature of 150° C. at the capsules for the time indicated below in Table 1.

[0093] 3. Vapor Phase

[0094] The C.sub.16 FAC was placed in a Petri dish having a grill paced on top. The capsules were placed on top of the grill. The Petri dish with grill and capsules on top were placed in a desiccator, which was placed in an oven at 180° C. for the time indicated below in Table 1. For the vapor phase trials, the oven was set at 180° C. to reach 150° C. in the reactor more rapidly.

TABLE-US-00001 TABLE 1 C.sub.16 Grafting Conditions 2 min 4 min 5 min 8 min 10 min 15 min 20 min 30 min Oven Both Both Both 150° C. Heat Gun Both Both Both 150° C. Vapor Phase Both Viscopearl Menthol Both Viscopearl 180° C.

[0095] B. C.sub.11 Fatty Acid Chloride Grafting

[0096] Menthol capsules and Viscopearl were grafted with a C.sub.11 fatty acid chloride (C.sub.11 FAC) using three grafting techniques to determine which grafting techniques may work well to produce capsules with a hydrophobic shell. The grafting reacts the fatty acid chlorides with hydroxyl groups present on the surface of the shells of the capsules to covalently bond the fatty acid to the shell. The by-product of the reaction is hydrochloric acid, which is evacuated.

[0097] The three grafting techniques employed are outlined below:

[0098] 1. Oven

[0099] A reagent mix solution was prepared by introducing the C.sub.11 FAC (2% by weight) in a solvent (petroleum ether, 98%). The capsules were immersed in the reagent mix solution for a few minutes and removed from the reagent mix solution. The residual solvent was evaporated from the capsules at room temperature for a few minutes. The capsules were then placed in an oven, which was kept under nitrogen flux at 850 mbar pressure and at a temperature of 80° C. for the time indicated below in Table 2, or kept under atmospheric conditions at a temperature of 80° C. for the time indicated below in Table 2.

[0100] 2. Heat Gun

[0101] A reagent mix solution was prepared by introducing the C.sub.11 FAC (2% by weight) in a solvent (petroleum ether, 98%). The capsules were immersed in the reagent mix solution for a few minutes and removed from the reagent mix solution. The residual solvent was evaporated from the capsules at room temperature for a few minutes. The C.sub.11 FAC was grafted to the capsule surface by directing a heat gun set at a temperature of 80° C. at the capsules for the time indicated below in Table 2.

[0102] 3. Vapor Phase

[0103] The C.sub.11 FAC was placed in a Petri dish having a grill placed on top. The capsules were placed on top of the grill. The Petri dish with grill and capsules on top were placed on a ring of blotter paper, which were placed in an oven at the temperatures and times indicated below in Table 2.

TABLE-US-00002 TABLE 2 C.sub.11 Grafting Conditions 4 min 8 min 10 min 20 min Oven 80° C. Menthol Heat Gun 80° C. Both Both Menthol Vapor 80° C. Both Both Menthol Vapor 100° C. Menthol Vapour 120° C. Menthol

[0104] C. Immersion in Water

[0105] The grafted capsules were placed in water and their behaviour was observed. For example, the general appearance of the capsules was noted, the percent of capsules that floated was noted, and the time to discoloration of menthol capsules was noted.

[0106] D. Measurement of Gradual Weight Gain when Placed in a Tropical Environment

[0107] The grafted capsules were placed in a controlled environment (“Tropical environment”) at 38° C. and 90% relative humidity, and their mass was measured at predetermined times to determine the amount of weight they gained due to moisture absorption.

[0108] E. Measurement of Surface Tension

[0109] Surface tension measurement was performed only on the Menthol capsules. Due to the smaller size of the Viscopearl, surface tension measurements were not taken for the Viscopearl. The Menthol capsules were put on a small rod using adhesive tape, and the test was carried out with Kruss equipment with a custom geometry (cylinder of 3 mm diameter and 3 mm height), and an immersion depth of 1.5 mm, for a duration of 60 s. The absolute mass of water taken up by the capsule was measured. The experiment is designed to estimate the effectiveness of the grafting, where the lower the mass, the more effective was the grafting.

[0110] F. Measurement of Color Leaking

[0111] The amount of colorant that was leaked from the menthol capsules was measured using UV-VIS spectrophotometry. For each sample, 3 capsules were put in an appropriate spectrophotometer measurement cell in distilled water, and the absorbance was measured at 286 nm after 1 min.

II. Results

[0112] Several observations were made following the C.sub.16 FAC trials. Some initial observations are presented below in Table 3 (for Menthol capsules) and Table 4 (for Viscopearl).

TABLE-US-00003 TABLE 3 Observations for Menthol Capsules Menthol Capsules Oven The capsules were whitened when coming out of the oven. 150° C. There was a slight difference with ungrafted samples (which started discolorating after 8-9 s in water) when put in water: discoloration was not slower (~10 s), but seemed less important. The grafting did not seem efficient: the capsules did not particularly repel water and did seem to float better than ungrafted capsules. Heat Gun The capsules were also whitened after heating, especially after 4 min. They 150° C. regained their green color after 8 min of heating. After 2 min of heating, the capsules still looked wet, which was likely due to some petroleum ether remaining. When put into water, discoloration started after about 12 s (2 min of heating) or 17 s (4 and 8 min of heating). The capsules seemed grafted, with better results when put in water (less discoloration and better floating) after 4 and 8 min of grafting. Vapor Phase With this technique, the capsules do not whiten. 180° C. But time may be important for this process: after 5 min, the capsules were not grafted (no difference when put in water), and after 20 min, they did not keep their integrity when cooling down (bursting) and as a result were covered in menthol. However after 15 min, the capsules were still solid, not whitened, and could spend around 40 s in water before discoloration started, with better floating.

TABLE-US-00004 TABLE 4 Observations for Viscopearl Viscopearl Oven The Viscopearl seemed whiter when they came out of the oven, especially at 150° C. 2 and 4 min of grafting. Under 8 min spent in the oven, they tended to agglomerate and still look humid, with petroleum ether remaining. After 8 min of grafting, the grafted Viscopearl looked like the ungrafted Viscopearl. When put in water, the Viscopearls sank almost immediately; grafting did not seem efficient. Heat Gun The Viscopearl were close in aspect to the ungrafted capsules. 150° C. Some (less than with the oven method) solvent appeared to remain after grafting. There was a clear difference between ungrafted and grafted samples, with grafted samples floating in water (some still sink), and less sample sinking with grafting time rising (from about 70/30 to 90/10, in %). Vapor Phase Again, time was clearly critical for this process: the longer the Viscopearl 180° C. remained in the oven, the blacker they come out. Unexpectedly grafting did not seem to work with this method on these Viscopearl: they sank in water whatever grafting time is used.

[0113] In general the grafting of the C.sub.16 FAC was observed to be more effective than the grafting of the C.sub.11 FAC regarding reaction to water, such as increased floating and less color leaking.

[0114] Capsules were observed to degrade when exposed to elevated temperatures for extended periods of time. Even at 80° C., the capsules degraded when they remained exposed too long.

[0115] There was no difference observed between weight gain in capsules that were not grafted and grafted capsules placed at 38° C. and 90% RH.

[0116] The results of immersing the Viscopearl into water are detailed in Table 5 below.

TABLE-US-00005 TABLE 5 Results of placing C.sub.16 FAC grafted Viscopearl into water Viscopearl with C.sub.16 2 min 4 min 5 min 8 min 10 min 20 min 30 min Oven 50% float 50-60% float — 50-60% float — — — 150° C., 50% sink 40-50% sink 40-50% sink 850 mBar Heat Gun 70% float 80% float — 90% float — — — 150° C. 30% sink 20% sink 10% sink Vapor — — Sink — Sink Sink Sink Phase 180° C.
All the Viscopearl treated with C.sub.11 FAC sank when put in water.

[0117] For the Menthol capsules, their behaviour in water was easier to quantify due to colorant leaking out after a few seconds of immersion. Table 6 below summarizes the time needed, in seconds, for the leakage of the colorant in the different trials. For a point of comparison, Menthol capsules that were not grafted started to bleed colorant after 8 seconds in water.

TABLE-US-00006 TABLE 6 Time to colorant leaking from C.sub.16 FAC treated Menthol capsules 2 min 4 min 5 min 8 min 15 min Oven at 150° C.  8 s  8 s — 11 s — Heat gun at 12 s 18 s — 18 s — 150° C. Vapor phase — — 8 s — 40 s 180° C.

[0118] The UV absorption results (to test the amount of colorant that leaked) presented in FIG. 5 confirm the previous observations: grafting in the oven slightly improves resistance to water, while grafting with the heat gun or for a long enough time in vapor phase clearly improves resistance to water. For these conditions, the colorant bleeds much slower, resulting in a lower value in absorbance measurement.

[0119] Table 7 below provides the mass measured over time (two measurements per condition). In theory, the lower the mass, the better the grafting.

TABLE-US-00007 TABLE 7 Mass taken up by the Menthol capsules in surface tension tests C16 C16 C16 C16 C16 C16 C16 C16 Oven Oven Oven Oven Oven Oven Heat Heat Time 2 min 4 min 8 min 2 min 4 min 8 min Gun Gun (s) Ungrafted 1 bar 1 bar 1 bar 850 mBar 850 mbar 850 mbar 2 min 2 min  1 61.8 80.7 81.5 61.6 18.8 16.4 15.3 117.7 17.5  7 62.2 81.3 82.0 62.4 18.9 16.4 15.4 117.9 17.2 14 62.8 81.8 82.6 63.4 19.0 16.5 15.4 118.7 16.9 21 63.4 82.3 83.0 63.9 19.1 16.6 15.7 119.2 16.8 27 63.7 82.6 83.2 64.2 19.1 16.6 15.8 119.5 16.6 34 64.1 82.7 83.5 64.4 19.2 16.7 15.9 120.0 16.4 41 64.4 83.0 83.8 64.6 19.2 16.7 16.0 120.3 16.3 47 64.6 83.2 84.0 64.7 19.3 16.7 16.1 120.7 16.2 54 64.9 83.4 84.2 64.9 19.3 16.7 16.1 121.0 16.0 60 65.1 83.5 84.4 65.0 19.4 16.7 16.1 121.1 15.9 C11 C11 C16 C16 C16 C11 C11 C11 Vapor Vapor Heat Vapor Vapor Oven Heat Heat phase phase Time Gun phase phase 10 min Gun Gun 80° C. 1000° C. (s) 8 min 5 min 15 min 850 mBar 4 min 8 min 20 min 20 min  1 46.7 63.1 63.1 58.2 80.9 80.6 64.2 62.4  7 46.5 63.5 63.4 58.1 81.6 81.2 64.8 62.7 14 46.5 63.9 63.5 58.2 82.3 81.8 65.2 63.2 21 46.3 64.3 63.7 58.2 82.7 82.4 65.5 63.5 27 46.2 64.6 63.7 58.4 83.1 82.6 65.9 63.6 34 46.2 65.0 63.8 58.5 83.4 83.0 66.1 63.8 41 46.2 65.2 63.8 58.6 83.7 83.3 66.4 64.0 47 46.3 65.4 63.8 58.6 83.9 83.5 66.6 64.1 54 46.3 65.6 63.9 58.7 84.1 83.8 66.7 64.2 60 46.3 65.8 63.9 58.7 84.3 84.0 66.8 64.4

[0120] FIG. 6 presents the results from Table 7 in graphical form. As indicated, surface tension measurements appear to suggest that grafting using a heat gun for 4 minutes and grafting in the oven resulted in less water absorption by the capsules.

[0121] From surface tension measurements alone we would deduce that grafting in the oven or with the heat gun are better solutions than grafting in vapour phase

III. Conclusion

[0122] In conclusion, covalent bonding of fatty acid moieties to the surface of the capsules may be achieved through a number of techniques. For example, covalent bonding under a hot air flow and in vapor phase with pure reagent seems to work well. These techniques may be optimized, improved and scaled up for industrial scale covalent bonding of hydrophobic moieties to surfaces of capsules, e.g. by using a fluidized bed.

Example 3: Sensory Testing

[0123] Capsules comprising menthol and having a shell comprising gelatin (V. Mane Fils) (“Menthol capsules”) were treated with C.sub.16 fatty acid chloride to graft a Cm fatty acid moiety to the surface of the Menthol capsules using four different processes. The processes were carried out generally as described above in Example 2 and included (i) heat gun treatment at 150° C. for 8 minutes; (ii) oven at 150° C. for 8 minutes; (iii) oven at 150° C. for 4 minutes; and (iv) vapor phase at 180° C. for 4 minutes.

[0124] The Menthol capsules were incorporated into the filter of prototypes of a smoking article comprising a rod of crimped cast leaf tobacco and a filter comprising a segment of cellulose acetate tow (similar to HEETS™. Nine panellists tested three different samples of each prototype (containing a capsule treated using a different process) over four sessions. In each session, the panellists tested three prototypes, each containing a Menthol capsule that underwent the same treatment protocol. Panellists consumed the smoking articles containing treated Menthol capsules using a iQOS-branded tobacco heating device and provided their sensory perception regarding the leaking of flavour (minty/cooling sensation), a dull clicking sound when the capsule breaks (the “sound to click”) and the tactile sensation of the capsule breaking between the fingers at the end of the test.

[0125] To test for leakage of the flavor, the panellists consumed the smoking article (at least ten puffs) and were asked to evaluate whether they perceived a minty aroma, a cooling sensation, or both a minty aroma and a cooling sensation. If they perceived a sensation, the panelists were asked to indicate at what puff the sensation was perceived. At the end of each run, the panellists were asked to try to break the capsule and to tell if they perceived a tactile sensation of capsule breakage and a sound, just a sensation (no sound), or nothing (no sensation and no sound).

[0126] Data from one of the panellists for the “sound to click” test were removed from the analysis because the panellist was not pressing where the capsule was located.

[0127] Results are presented in FIGS. 7-8. In FIG. 7, a plot of leakage frequency per capsule is shown. Occurrence frequencies were calculated from the results of nine panellists for a total of 27 samples per prototype tested. In FIG. 8, the “sound to click” results are presented. Occurrence frequencies were calculated from the results of eight panellists for a total of 24 samples per prototype tested.

[0128] As shown in FIG. 7, while the leakage occurrence frequency was around 90% for both capsules (i) and (iv), only 30% leakages were observed for the capsule (ii) and no leakage was observed for the capsule (iii). Looking at the panellists' comments, we observed that for the three capsules showing leakages [capsules (i), (ii) and (iv)], panellists mentioned that only very low intensity of minty aroma or cooling sensation were perceived. It is possible that very slight leakages of the capsules or even a contamination of the samples occurred prior the evaluation due to capsules already broken or already leaking before the evaluation, which may have contaminated the whole jar of samples. Further analysis is warranted.

[0129] In terms of the “sound to click”, FIG. 8, capsules (i), (ii) and (iii) obtained very close results with around 80% of the samples still eliciting the tactile sensation and sound to click at the end of the run. For the capsule (iv), we observed lower proportion of the samples maintaining sensation and sound to click at the end of the run, with higher proportion of samples eliciting only sensation but no sound to click.

Example 4: Distance at Break and Resistance to Click

[0130] Menthol capsules were grafted with 2% C.sub.16 fatty acid chloride as described in Example 2 above. The average weight of the Menthol capsules was 21.1 mg (n=50). The Menthol capsules were treated at 150° C. with a heat gun for 4 minutes or 8 minutes, at 150° C. for 8 min under 850 mbar pressure in an oven, or at 150° C. for the vapor phase.

[0131] Resistance to click and distance at breakage were determined as follows. Briefly, an Instron universal tensile/compression testing machine equipped with a 100N tension load cell was employed. A lower compression plate having a diameter of 150 mm and an upper compression plate, resistant to the capacity of the load cell, and having a diameter of 20 mm was employed. The Menthol capsules were placed on the center of the lower plate. The upper plate was lowered towards the Menthol capsule and lower plate at about 30 mm/min. The testing was performed at 22° C. under 60 percent relative humidity.

[0132] The distance the upper plate moved (in mm, distance at break) after contacting the Menthol capsule and the load (in Newtons, resistance to click) was measured. An abrupt drop in load occurred when the capsules broke, Results are presented below in Tables 8-11.

TABLE-US-00008 TABLE 8 Heat gun, 4 min DaB (mm) RTC (N) 1 0.78 18.3 2 0.83 18.2 3 0.6 18.2 4 0.77 18.7 5 0.73 16.7 6 0.8 20.1 7 0.9 23 8 0.76 19.4 9 0.78 16.5 10 0.77 17.8 Average 0.77 18.7

TABLE-US-00009 TABLE 9 Heat gun 8 min DaB (mm) RTC (N) 1 0.71 15.4 2 0.82 17.7 3 0.67 10.7 4 0.68 13.7 5 0.81 19 6 0.48 5.6 7 0.74 16.4 8 0.82 16.4 9 0.81 14.7 10 0.79 17.8 Average 0.73 14.7

TABLE-US-00010 TABLE 10 Vapor phase DaB (mm) RTC (N) 1 0.79 14.4 2 1.09 25.2 3 1.06 22.4 4 0.72 20.4 5 0.84 16.2 6 0.91 17.1 7 0.6 15.7 8 0.87 16.7 9 0.68 12.4 10 0.81 14.7 Average 0.84 17.5

TABLE-US-00011 TABLE 11 Oven DaB (mm) RTC (N) 1 0.7 16.9 2 0.95 18.3 3 0.92 20.2 4 0.71 15.9 5 0.99 19.9 6 0.65 11.1 7 0.75 17.1 8 0.45 8.2 9 0.81 20.1 10 1.21 18.2 Average 0.81 16.6

CONCLUSIONS

[0133] The results show that capsules comprising a flavorant and a breakable shell can be treated by a variety of methods and conditions with an acid chloride comprising a fatty acid moiety. The treated capsules are is resistant to moisture and yet retain much of their performance characteristics when they are compressed to breakage.

[0134] The embodiments exemplified above are not limiting. Other embodiments consistent with the embodiments described above will be apparent to those skilled in the art.

[0135] Each patent, published patent application, journal article and other publicly available information cited herein is hereby incorporated herein by reference in its respective entirety to the extent that it does not conflict with the disclosure presented herein.