STABILISATION OF FLAVOURANTS

Abstract: A method of stabilising flavourants, volatile flavourants in particular, comprising encapsulating the flavourants in a carageenan gel structure. The encapsulated flavourant will only be released upon exposure of the stabilised flavourant to elevated temperatures.

Description: Stabilisation of Flavourants The present invention relates to the stabilisation of flavourants. In the flavour industry it is commonly known that some flavourants are too volatile or odorous to be used directly on, for example, foodstuff products. One way of overcoming this problem is to encapsulate the flavour molecules to restrain the volatile nature thereof. A method of encapsulating flavourants at the molecular level involves the use of β-cyclodextrin as the encapsulating agent. See, for example, European Patent Application No. 0 503 795-A2. The method of encapsulating flavourants using β- cyclodextrin may proceed under a variety of process conditions, the following being an example of such a method. A solution of β-cyclodextrin is heated to around 80°C, whereupon the β-cyclodextrin molecules break open. The flavourant is then added to the warm solution and the resultant mixture is left to cool. As the mixture cools opened β-cyclodextrin rings re-form around the flavour molecules. Hence, at lease one flavour molecule is stabilised within the β-cyclodextrin ring. A problem with the β-cyclodextrin method of encapsulation is that due to the size of the internal cavity of the β- cyclodextrin ring only a limited number of flavour molecules can be stabilised (encapsulated) per β-cyclodextrin ring. In most cases only one flavour molecule can be stabilised per β- cyclodextrin ring. Therefore, the loading level of flavourant in unit amount of β-cyclodextrin is limited. In addition, if the flavourant is a mixture of different flavour molecules, the β-cyclodextrin may selectively encapsulate a certain type(s) of the flavour molecules in preference to others, and so unbalance a mixed flavour composition. It is taught in GB 1, 163,023 that flavour molecules may be stabilised by forming a wall of material around the flavour molecules. In this case, a mixture of reactants including a carageenate compound, produce a capsule wall around the flavour molecules. The present invention seeks to overcome the problems of the prior art and to provide an alternative thereto. The present invention provides a method of stabilising a flavourant, wherein an ionic solution and a mixture, said mixture comprising both carageenan and said flavourant, and said carageenan at least being in the form of a sol, are intercontacted, thus to effect a sol to gel transformation of said carageenan and thereby the trapping of said flavourant within the carageenan gel. The present invention further provides a stabilised flavourant, comprising said flavourant trapped in carageenan. By carageenan (also known as carrageenan, carrageenin and carragheenin) we mean the carageenan gum extract of carageenan seaweed. Preferably the carageenan is substantially in the K- carageenan form. Carageenan derivatives may also be suitable. Furthermore the carageenan, prior to the sol to gel transformation, preferably takes the form of a slurry. Preferably the carageenan slurry is an aqueous solution, and much by preference, comprises de-ionised water. The concentration of the carageenan in the slurry should be no more than 1% by weight. The carageenan may be mixed with the flavourant before the carageenan is made into a sol, or the carageenan may be mixed with de-ionised water to form a sol before it is mixed with the flavourant. The flavourant may disolve in the liquid of the sol or the flavourant may become suspended in the sol as an emulsion. The order of mixing of the carageenan and the flavourant relative to the addition of liquid and whether or not the flavourant will dissolve in the liquid of the sol may depend upon the nature of the flavourant. The ionic solution is preferably an aqueous ionic solution, which aqueouε ionic solution provides much by preference a source of potassium ions. Aqueous potassium chloride is a suitable aqueous ionic solution. Preferably, the aqueous ionic solution is a saturated solution. Most flavour compounds, or mixtures thereof, except possibly protein flavours, are suitable for use in accordance with the method of the present invention. In the case of protein flavours, the highly charged nature of the protein flavourant molecules disrupts the gel formation of the carageenan. However, it may be possible to stabilise proteins as denatured proteins according to the above described inventive method. When used for tobacco products, essential oils, natural extracts and blended flavour formulations are particularly suitable flavourants. Particularly suitable for use in the tobacco industry are, for example, menthol, vanallin, benzaldehyde, cinamaldehyde, furaneol, herb oils, spice oils and citrus oils. The stabilised flavourant of the present invention may take the form of a carageenan matrix throughout which the flavourant is dispersed. Alternatively, the stabilised flavourant may take the form of a volume of flavourant encapsulated in a casing of carageenan. The form of the stabilised flavourant will be determined by the method of production thereof. In carrying out the inventive method, the carageenan/flavourant mixture may be added to the ionic solution dropwise. This method of addition may result in the formation of discrete particles of stabilised flavourant, each particle providing a carageenan matrix in which the flavourant is dispersed. As an alternative, the carageenan/ flavourant mixture can be injected into the ionic solution in a manner such that elongate particleε in the form of strands of stabilised flavourant are produced. More practically in industry, the mixture of carageenan and flavourant may be sprayed by means of an atomiser into the ionic solution. The particles of stabilised flavourant thus produced may be separated from the ionic solution by sedimentation or floatation. This method of addition may result in the formation of a free flowing powder. Altematively, the carageenan sol may be co-extruded with the flavourant into the ionic solution. A suitable method of co-extrusion is disclosed as "Centrifugal Extrusion Encapsulation" in the book entitled "Encapsulation and Controlled Release of Food Ingredients" by Risch and Reineccius, published by the American Chemical Society. In this case the stabilised flavourant may be produced as spherical particles of encapsulated flavourant. A further alternative involves the addition of the ionic solution to the mixture of carageenan and flavourant. In this case, a monolithic body of carageenan gel forms with the flavourant dispersed throughout said body. The monolithic body may then be sliced and dried and then shredded in order to form shreds of stabilised flavourant. Upon being produced, the stabilised flavourant produced may be dried in air. The particles of stabilised flavourant will be reduced in size upon drying owing to loss of water from the particles. An advantage of the stabilised flavourant as formed in accordance with the inventive method lies in the fact that stabilised flavourant particles in the form of, for example, shreds, strands or spherical particles are stable at elevated temperatures, for example, up to 180°C. Furthermore, flavourant which is dispersed in the carageenan will generally not be released by subjecting the particles to elevated pressures or moisture. As would be appreciated by a person skilled in the art, the thermal stability of the stabilised flavourant ensures that the flavourant will not be released under normal processing conditions. For example, when used in the tobacco industry, particles of stabilised flavourant can withstand the processing conditions of smoking material or smoking article production without the flavourant being released. However, at higher temperatures, for example, when the smoking article is smoked the carageenan structure will break up to release the flavourant. A further advantage of the present invention is that a high level of flavourant may be stabilised per unit amount of carageenan. In a case where the flavourant comprises a mixture of different types of flavourants, carageenan can stabilise the flavourant as a mixture of flavourants, rather than selectively stabilising certain types of flavourant from a mixture of different types of flavourants. An inventive stabilised flavourant may be used in foodstuff products, such as, for example, encapsulated onion oil being incorporated in burgers. When used in foodstuff products, the stabilised flavourant will be released upon cooking. Inventive stabilised flavourants may also be added to tobacco for use in smoking articles. For example, particles of stable flavourant may be added during the production of reconstituted tobacco (US 3,540,456 discloses a suitable method of producing reconstituted tobacco) . An alternative use of the inventive stabilised flavourants resideε in the incorporation of the stabilised flavourant in an outer wrapper of the smoking article. In the case of use of the inventive stabilised flavourants in smoking articles, the flavour will be released upon smoking of the smoking article whereupon heat from the burning coal will facilitate releaεe of the flavourant from the carageenan. The following example is further illustrative of the present invention. The specific compounds and process parameters are presented as being typical, and various modifications can be derived in view of the foregoing disclosure. EXAMPLE 1 A 1% wt/wt sol of K-carageenan was produced by adding the κ-carageenan to de-ionised water at about 20°C. Dill seed oil as a flavourant, was added to the aqueous K-carageenan sol with stirring. The sol was added to a saturated solution of potassium chloride using a pasteur pipette. A sol to gel reaction took place on contact of the carageenan/flavourant mixture with the saturated solution of potassium chloride. Discrete particles were formed compriεing a carageenan gel matrix in which the flavourant was dispersed. The particles were εkimmed off the surface of the potassium chloride solution and washed with 90% ethanol in water. The washed particles were then dried in air at room temperature, during which drying process the particles shrunk to about 25% of the original volume and became rigid.

Claims: CLAIMS 1. A method of stabilising a flavourant, wherein an ionic solution and a mixture, said mixture compriεing both carageenan and said flavourant, and said carageenan at least being in the form of a sol, are intercontacted, thus to effect a sol to gel transformation of said carageenan and thereby the trapping of said flavourant within the carageenan gel. 2. A method according to Claim 1, wherein said carageenan is in the k-carageenan form. 3. A method according to Claims 1 or 2, wherein said carageenan sol is in the form of a slurry. 4. A method according to Claim 1, 2 or 3, wherein the water component of said sol is de-ionised water. 5. A method according to any one of the preceeding claims, wherein the concentration of carageenan in said sol is no more than about 1%. 6. A method according to any one of the preceeding claims, wherein said flavourant is mixed with said carageenan before said carageenan is formed into said sol. 7. A method according to any one of Claims 1 to 5, wherein said flavourant is added to said sol. 8. A method according to any one of the preceding claims, wherein said ionic solution is an aqueous ionic solution. 9. A method according to Claim 8, wherein said aqueous ionic solution is an aqueous potassium salt solution. 10. A method according to Claim 9, wherein said potaεsium salt is potassium chloride. 11. A method according to any one of the preceding claims, wherein said mixture of carageenan and flavourant is added to said ionic solution. 12. A method according to Claim 11, wherein said mixture of carageenan and flavourant is injected into said ionic solution. 13. A method according to Claim 11, wherein said mixture of carageenan and flavourant is sprayed by meanε of an atomiser into said ionic solution. 14. A method according to any one of Claims 1 to 9, wherein said ionic solution is added to said mixture of carageenan and flavourant. 15. A stabilised flavourant, comprising said flavourant trapped in carageenan. 16. A stabilised flavourant according to Claim 15, comprising discrete particles of carageenan providing a matrix in which said flavourant is dispersed. 17. A stabilised flavourant according to Claim 15, comprising a monolithic body of carageenan within which body said flavourant is dispersed. 18. A stabilised flavourant according to Claim 15, comprising a volume of said flavourant encapsulated in a casing of carageenan. 19. A method substantially in accordance with Example 1 hereinabove. 20. A stabilised flavourant substantially in accordance with Example 1 hereinabove.

Inventors: O'REILLY ROSEMARY ELIZABETH, O'REILLY, ROSEMARY, ELIZABETH
Applicants: BRITISH AMERICAN TOBACCO CO, REILLY ROSEMARY ELIZABETH O, BRITISH-AMERICAN TOBACCO COMPANY LIMITED, O'REILLY, ROSEMARY, ELIZABETH
Application year: 1996
Main classification: A23L1
IPC codes: A23L1, A24B3, A24B15, A61K47, C11B9