Microcapsule for enhancing flavor of cigarette paper, cigarette paper containing the microcapsule and preparation method thereof

Abstract

The present invention relates to the field of tobacco technology, specifically to microcapsules for enhancing cigarette paper flavor, cigarette paper containing the microcapsules, and a method for preparing the same. The microcapsules comprise a core, which provides flavor and includes flavoring material and porous silica; a first wall material, which includes sodium alginate and chitosan; and a second wall material, which includes a layered mineral and polylactic acid. The present invention incorporates tobacco latent flavoring substances into the cigarette paper in the form of microcapsules. The microcapsules are also improved and added to the cigarette paper during the pulping process. The microcapsules are fully integrated into the cigarette paper, facilitating the preservation of flavor.

Description

Technical Field

[0001] The invention relates to the technical field of tobacco, in particular to a microcapsule for flavoring cigarette paper, cigarette paper containing the microcapsule and a preparation method thereof. Background Art

[0002] In recent years, research on cigarette paper flavoring has gradually increased both at home and abroad. Many countries and China Tobacco are studying the selection of tobacco latent aroma substances, such as various essential oils, to add to cigarette paper to achieve the purpose of flavoring.

[0003] Directly adding tobacco latent aroma compounds, most of which are volatile, quickly dissipates their fragrance, resulting in poor flavor enhancement. Therefore, tobacco latent aroma compounds are typically added in the form of microcapsules. By varying the flavor profile of the cigarette microcapsules, different flavors can be achieved. Among the numerous flavored cigarette design technologies, microencapsulation technology can improve the flavor embedding efficiency, effectively locking the flavor in the cigarette paper for a longer-lasting aroma.

[0004] The tobacco microcapsule technology in the prior art, for example, CN105919152A discloses a method for preparing a heat-not-burn tobacco substrate containing microcapsules, and CN102920013A discloses a tobacco extract microcapsule and its preparation method.

[0005] In the aforementioned patents and other prior art techniques not listed here, microcapsules are applied to the surface of cigarette paper by coating. This method is relatively convenient, simplifies production control, and ensures that the cigarette's unique aroma is experienced only when smoked. It has advantages such as no impact on the cigarette manufacturing process and no noticeable change to the customer, making it a preferred method for cigarette companies. However, since it is applied on the surface of the cigarette paper, it is easily detached during post-processing, resulting in a less noticeable aroma when smoked. Furthermore, the surface microcapsule coating can affect the gloss of the cigarette paper itself. Summary of the Invention

[0006] The purpose of the present invention is to provide a cigarette paper containing microcapsules and a preparation method thereof, wherein tobacco latent aroma substances are added to the cigarette paper in the form of microcapsules, and the microcapsules are improved and added to the pulping process of the cigarette paper. The microcapsules are completely integrated into the cigarette paper, which is conducive to the preservation of the aroma.

[0007] To achieve the above-mentioned purpose, the present invention is implemented through the following technical solutions:

[0008] In a first aspect, the present invention provides a microcapsule for enhancing the flavor of cigarette paper, comprising:

[0009] A core body, providing fragrance, comprising flavoring material and porous silica;

[0010] a first wall material comprising sodium alginate and chitosan;

[0011] The second wall material includes layered structure minerals and polylactic acid.

[0012] As discussed in the background, prior art microcapsules are formed on the surface of cigarette paper by coating, which inevitably leads to certain drawbacks, such as easy detachment. The applicant's analysis reveals that prior art microcapsules are formed by coating rather than directly adding them to the pulp of cigarette paper because they have poor stability in solution and cannot withstand mechanical forces during the papermaking process, easily damaging the capsule structure. Therefore, direct addition of microcapsules to the pulp is unsuitable.

[0013] Based on the above reasons, the applicant has improved the composition and structure of the microcapsules. Compared to existing microcapsules, porous silica is used as a carrier for the flavor. Porous silica has abundant pores, which improves the loading efficiency of the flavor. Moreover, the flavor is adsorbed within the pores of the porous silica, making it more stable. The complex of the flavor and porous silica is encapsulated by a wall material composed of sodium alginate and chitosan, forming a stable, independent primary microcapsule. Secondly, a secondary wall material is added outside the wall material, and the primary microcapsules are adsorbed on the layered mineral. Then, polylactic acid is used as the main body to encapsulate the primary microcapsules to form the microcapsules.

[0014] The reason why polylactic acid is selected as the second wall material in the present invention is that compared with other wall materials, it has a higher encapsulation rate for the flavor material and is particularly suitable in the present invention.

[0015] The resulting microcapsules can be added as fillers during the cigarette papermaking process. They are resistant to external forces such as stirring and shearing during the papermaking process. Once added, they remain stable within the cigarette paper as microcapsules. Compared to coatings formed on the surface of the cigarette paper, they are less likely to fall off and do not affect the surface properties of the cigarette paper. During smoking, the high temperature causes the flavoring material inside the microcapsules to volatilize, releasing a unique aroma.

[0016] Preferably, in the first wall material, the mass ratio of sodium alginate to chitosan is 3:0.5-0.8.

[0017] Preferably, the mass ratio of the flavor material to the porous silica is 2-3:1.

[0018] Preferably, the particle size of the porous silica is 0.5 μm to 2 μm.

[0019] Preferably, the layered structure mineral is one, two or three of montmorillonite, vermiculite and mica.

[0020] Preferably, the layered structure mineral is subjected to high temperature treatment before use, and the treatment operation is: soaking the layered structure mineral in acetic acid, then drying it at low temperature, and then subjecting it to heat treatment under high temperature conditions.

[0021] While the aforementioned microcapsules offer excellent encapsulation and stability, the applicants have discovered that the brief heating of the cigarette during use prevents the complete release of the flavoring material within the microcapsules, impacting the flavoring effect. Typically, the release rate is only around 60%, with the remaining flavor material carried along with the microcapsules into the cigarette ash, resulting in waste.

[0022] After numerous experiments, the inventors discovered that the primary factor affecting flavor release is the layered minerals in the second wall material. In a preferred embodiment of the present invention, the layered minerals undergo a pretreatment. At high temperatures, they expand to a certain extent. By controlling the treatment temperature and time, this expansion allows the cigarette to typically reach surface temperatures of 200°C to 300°C and core temperatures of 500°C to 800°C during inhalation, making the second wall material more susceptible to damage. Once damaged, the high temperature accelerates the melting of chitosan (melting point 102.5°C), enhancing flavor release. A comparative study showed that pretreatment with layered minerals resulted in a flavor release rate of approximately 95%.

[0023] The second aspect of the present invention is to provide a method for preparing the above-mentioned microcapsules, comprising the following steps:

[0024] S-11. Dissolving the flavor in a cosolvent to obtain a flavor solution;

[0025] S-12. The porous silica was added to the flavor solution and incubated at 30°C to 45°C overnight to obtain a flavor-loaded solution;

[0026] S-13. The flavor material loading solution was added to the sodium alginate solution, stirred at high speed, and then the chitosan solution was added, and stirring was continued to prepare a primary microcapsule solution;

[0027] S-14. Disperse the powdered layered mineral evenly in the primary microcapsule solution and stir overnight at 30°C to 45°C.

[0028] S-15. Prepare polylactic acid into an emulsion, add it to the solution obtained in step S-4, stir, concentrate, and spray-dry to obtain microcapsules.

[0029] The third aspect of the present invention provides a cigarette paper comprising the above-mentioned flavoring microcapsules.

[0030] Preferably, the microcapsules are added to the cigarette paper in a form other than coating on the surface of the cigarette paper.

[0031] A fourth aspect of the present invention provides a method for preparing cigarette paper, comprising the following steps:

[0032] S-21. Preparation of cigarette pulp: beating the cigarette paper fibers to 50°SR~80°SR;

[0033] S-22. Add the above-mentioned flavoring microcapsules to the cigarette pulp and stir thoroughly;

[0034] S-23. Forming: Add fillers and additives to the prepared mixed slurry, form wet paper sheets, and dry them to obtain cigarette paper with a flavoring effect.

[0035] By implementing the above technical solution, the present invention has the following beneficial effects:

[0036] The present invention improves the structure of the microcapsule. The inner core uses porous silica as a carrier for the flavoring material. The rich pores of the porous silica improve the loading efficiency and loading stability of the flavoring material. The core is wrapped in a wall material composed of sodium alginate and chitosan to form a stable and independent primary microcapsule. Secondly, a second wall material is added to the outside of the wall material. The interlayers of the layered minerals in the second wall material have abundant and large-area voids. The primary microcapsules are adsorbed in the voids. Then, polylactic acid is used as the main body to wrap them to form microcapsules. The microcapsules are suitable for being added to cigarette paper in a form that is not coated on the surface of the cigarette paper, especially when added to cigarette pulp during the preparation process of the cigarette paper. When added to the inside of the cigarette paper, the microcapsules are not easy to fall off. The microcapsules are completely integrated into the cigarette paper, which is also more conducive to the enhancement of the flavor. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the specification and specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only a portion of the embodiments of the present invention, rather than all of the embodiments. Therefore, all other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0038] The difference between the present invention and the prior art is that the microcapsules for enhancing the flavor of cigarette paper are wrapped twice, that is, the first wall material and the second wall material are wrapped outside the core.

[0039] Core body

[0040] To provide fragrance, in addition to the fragrance, porous silica is also added. Before being wrapped with the wall material, the fragrance is loaded through the porous silica, and the rich pores of the porous silica improve the stability of the fragrance.

[0041] Flavoring materials can be any materials that can provide fragrance, such as tea flavor, coffee flavor, mint flavor, milk flavor, orange flavor, lime flavor, etc. It can be one of them or a mixture of several, as long as it suits the taste of consumers.

[0042] The particle size of the porous silica is selected to be in the range of 0.5 μm to 2 μm. The porous silica in this range has better agglomeration properties during the subsequent wrapping process by the first wall material and is more likely to form primary microcapsules.

[0043] First wall material

[0044] This example uses a sodium alginate-chitosan composite wall material. The sodium alginate molecular chain contains a large number of -COOH groups, while the chitosan molecular chain contains a large number of -NH2 groups. These groups are electrostatically attracted to each other, forming a double electrical layer that coats the porous silica surface loaded with the flavoring material, forming a more stable coating. The mass ratio of sodium alginate to chitosan is 3:3-5.

[0045] Sodium alginate and chitosan were used in the form of solutions, with the concentration of the sodium alginate solution being 5% (w / V) and the concentration of the chitosan solution being 5% (w / V).

[0046] Second wall material

[0047] Including layered structure minerals and polylactic acid.

[0048] The layered mineral can be any layered mineral, and in particular, one, two, or three of montmorillonite, vermiculite, and mica are selected. These three are all common layered minerals, and the raw materials are easily available and inexpensive.

[0049] The layered minerals are added in powder form, with a typical particle size of 50 to 80 μm. The interlayer gaps formed by layered minerals within this range are more conducive to the inclusion of flavoring materials wrapped in the sodium alginate-chitosan composite wall material.

[0050] Layered minerals can be used directly, but the inventors discovered that the release rate of flavoring materials during smoking is limited. To address this limitation, the layered minerals are subjected to a high-temperature treatment before use. The treatment involves soaking the layered minerals in acetic acid, drying them at low temperature, and then subjecting them to a high-temperature heat treatment.

[0051] The acetic acid concentration is selected to be 10% to 20%, and the drying temperature does not exceed 150°C. There is no special lower limit. Exceeding 150°C will affect the heat treatment effect. The high temperature of heat treatment refers to 300°C to 350°C, and the treatment time is 40min to 60min.

[0052] Polylactic acid (PLA) is an environmentally friendly, renewable, and readily available material widely used in cigarettes. The choice of PLA here not only takes into account these advantages but also the flavoring's encapsulation and release properties.

[0053] When in use, polylactic acid is first prepared into a polylactic acid solution using an organic solvent, for example, using dichloromethane to prepare a polylactic acid solution with a concentration of 5 to 10 g / mL.

[0054] Example 1

[0055] This embodiment provides a flavoring microcapsule for cigarette paper, the composition and preparation method of which are as follows.

[0056] A microcapsule for cigarette paper flavoring comprises a core, a first wall material, and a second wall material. The core comprises coffee flavoring and porous silica, with a mass ratio of 2:1. The first wall material encapsulates the core to form a primary microcapsule. The first wall material is a composite material, sodium alginate-chitosan composite wall material, with a mass ratio of sodium alginate:chitosan = 1:1. The second wall material is a combination of a carrier material and a wrapping material. The carrier material is a layered mineral, mica in this embodiment, with the primary microcapsules loaded into the interlayer spaces. The wrapping material is polylactic acid.

[0057] The preparation method of the above microcapsules specifically comprises the following steps:

[0058] S-11. Dissolve 100 g of coffee flavor in 500 mL of water to obtain a flavor solution;

[0059] S-12. Add 50g of porous silica to the flavor solution and stir overnight at 45°C at a stirring speed of 350 r / min , obtaining a flavor-loaded solution;

[0060] S-13. The flavor-loaded solution was added to 500 mL of a 5% (W / V) sodium alginate solution, stirred at high speed, and then added to 500 mL of a 5% (W / V) chitosan solution. Stirring was continued to prepare a primary microcapsule solution.

[0061] S-14. 100g of high-temperature-treated powdered mica was evenly dispersed in the primary microcapsule solution and incubated at 30°C overnight. The high-temperature treatment of the mica involved soaking the montmorillonite in 15% acetic acid by volume for 4 hours, drying it at 100°C, and then incubating it at 350°C for 60 minutes.

[0062] S-15. Add 1000 mL of 5 g / mL polylactic acid to the solution obtained in step S-14, stir, concentrate, and spray dry to obtain microcapsules.

[0063] Example 2

[0064] This embodiment provides a microcapsule for cigarette paper flavoring, comprising a core, a first wall material, and a second wall material. The core comprises coffee-mint flavoring and porous silica, with a mass ratio of 3:1. The first wall material encapsulates the core to form a primary microcapsule. The first wall material is a composite material, sodium alginate-chitosan composite wall material, with a mass ratio of sodium alginate:chitosan of 3:2. The second wall material is a combination of a carrier material and a wrapping material. The carrier material is a layered mineral, in this embodiment, montmorillonite, with the primary microcapsules loaded into its interlayer spaces. The wrapping material is polylactic acid.

[0065] The preparation method of the above microcapsules specifically comprises the following steps:

[0066] S-11. Dissolve 100 g of mint flavor in 500 mL of solvent to obtain a flavor solution;

[0067] S-12. Add 50g of porous silica to the flavor solution and stir overnight at 40℃. 400 r / min, to obtain the flavor loading solution;

[0068] S-13. The flavor-loaded solution was added to 500 mL of a 5% (W / V) sodium alginate solution, stirred at high speed, and then added to 500 mL of a 5% (W / V) chitosan solution. Stirring was continued to prepare a primary microcapsule solution.

[0069] S-14. 100g of high-temperature-treated powdered montmorillonite was evenly dispersed in the primary microcapsule solution and incubated at 45°C overnight. The high-temperature treatment conditions for the montmorillonite were as follows: soak the montmorillonite in 10% acetic acid by volume for 6 hours, then dry it at 100°C, and then incubate it at 300°C for 40 minutes.

[0070] S-15. Add 1000 mL of 5 g / mL polylactic acid to the solution obtained in step S-14, stir, concentrate, and spray dry to obtain microcapsules.

[0071] Example 3

[0072] This embodiment provides a microcapsule for cigarette paper flavoring, comprising a core, a first wall material, and a second wall material. The core comprises mint flavoring and porous silica, with a mass ratio of 2.5:1. The first wall material wraps the core to form a primary microcapsule. The first wall material is a composite material, sodium alginate-chitosan composite wall material, with a mass ratio of sodium alginate:chitosan = 3:2. The second wall material is a combination of a load material and a wrapping material. The load material is a layered mineral, and the primary microcapsules are loaded in the interlayer spaces thereof. Montmorillonite is used in this embodiment and is used directly without high-temperature treatment. The wrapping material is polylactic acid.

[0073] The preparation method of the above microcapsules specifically comprises the following steps:

[0074] S-11. Dissolve 100 g of mint flavor in 500 mL of solvent to obtain a flavor solution;

[0075] S-12. Add 50g of porous silica to the flavor solution and stir overnight at 45°C at a stirring speed of 300 r / min, to obtain the flavor loading solution;

[0076] S-13. The flavor-loaded solution was added to 500 mL of a 5% (W / V) sodium alginate solution, stirred at high speed, and then added to 500 mL of a 5% (W / V) chitosan solution. Stirring was continued to prepare a primary microcapsule solution.

[0077] S-14. Disperse 100 g of powdered montmorillonite evenly in the primary microcapsule solution and incubate at 30°C overnight.

[0078] S-15. Add 1000 mL of 5 g / mL polylactic acid to the solution obtained in step S-14, stir, concentrate, and spray dry to obtain microcapsules.

[0079] Comparative Example 1:

[0080] The difference from Example 1 is that the second wall material is not provided. The microcapsules of this embodiment include a core and a first wall material. The core comprises coffee flavoring and porous silica, with a mass ratio of 2:1. The first wall material encapsulates the core to form a primary microcapsule. The first wall material is a composite material, sodium alginate-chitosan composite wall material, with a mass ratio of sodium alginate:chitosan = 1:1.

[0081] The preparation method of the above microcapsules specifically comprises the following steps:

[0082] S-11. Dissolve 100 g of coffee flavor in 500 mL of water to obtain a flavor solution;

[0083] S-12. Add 50g of porous silica to the flavor solution and stir overnight at 30°C to 45°C at a stirring speed of 350 r / min to obtain flavor loading solution;

[0084] S-13. Add the flavor-loaded solution to 500 mL of a 5% (W / V) sodium alginate solution and stir at high speed. Then add the solution to 500 mL of a 5% (W / V) chitosan solution and continue stirring to prepare a microcapsule solution. Concentrate the solution and spray-dry to obtain microcapsules.

[0085] Comparative Example 2:

[0086] The difference from Example 1 is that porous silicon dioxide is replaced by porous zirconium dioxide.

[0087] Comparative Example 3:

[0088] The difference from Example 1 is that the porous silica is replaced by activated carbon.

[0089] Comparative Example 4:

[0090] The difference from Example 1 is that no layered structure mineral is used in the second wall material, but polylactic acid is directly used to wrap the primary microcapsules.

[0091] Comparative Example 5:

[0092] The difference from Example 1 is that the layered structure mineral in the second wall material is replaced by porous silica.

[0093] The embedding efficiency of the microcapsules of the present invention (microcapsules obtained in Examples 1 to 3) and the microcapsules of the comparative examples was tested. The test results are shown in Table 1.

[0094]

[0095] As can be seen from the embedding rate results shown in Table 1, the microcapsules of the present invention have an embedding rate of up to 90%. In Comparative Example 1, the second wall material is not provided, and the embedding rate of spices decreases, being only 75%. This shows that the provision of the second wall material has a positive effect on the improvement of embedding rate. The embedding rate of Comparative Example 2 is comparable to that of Example 1, indicating that replacing porous silica with porous zirconium dioxide does not affect the embedding rate. The embedding rate of Comparative Example 3 decreases slightly compared to Example 1, indicating that the adsorption effect of activated carbon on spices is not as good as porous silica, which affects the embedding rate of spices. The embedding rate of Comparative Example 4 decreases significantly compared to Example 1, indicating that in the second layer, layered structure minerals are used, which is conducive to the improvement of embedding rate. The embedding rate of Comparative Example 5 decreases slightly compared to Example 1, indicating that in the second layer, layered structure minerals are used, which is more conducive to the improvement of embedding rate than porous silica.

[0096] Application Examples

[0097] A method for preparing cigarette paper comprises the following steps:

[0098] S-21. Preparation of cigarette pulp: beating the cigarette paper fibers to 50°SR~80°SR;

[0099] S-22. The microcapsules of each Example and Comparative Example were added to the cigarette pulp and stirred thoroughly. The microcapsules were added in an amount of 5g microcapsules / 100g of absolute dry pulp;

[0100] S-23. Papermaking and shaping: Add fillers and additives to the prepared mixed pulp, papermaking and shaping wet paper sheets, and drying; obtain cigarette paper with a flavoring effect.

[0101] The resulting cigarette paper was then used to make cigarettes using the same methods and steps. Aside from the cigarette paper, all other components of the cigarettes were identical. Blank cigarettes were cigarettes without any flavoring microcapsules added. Ten professional smokers conducted a comprehensive sensory quality evaluation, and the average score was calculated. The results are shown in Table 2.

[0102]

[0103] From the sensory evaluation results, it can be seen that the cigarettes added with the microcapsules of the present invention have a distinct characteristic aroma, and the fragrance is obvious, and can mask the woody smell, paper smell and other miscellaneous smells, reduce oral irritation, and improve the overall sensory quality of reconstituted tobacco.

[0104] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical concepts disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A microcapsule for cigarette paper flavoring, characterized in that: include: A core body, providing fragrance, comprising flavoring material and porous silica; a first wall material comprising sodium alginate and chitosan; The second wall material includes a layered structure mineral and polylactic acid. Before use, the layered structure mineral is soaked in acetic acid, then dried at low temperature, and then subjected to heat treatment under high temperature conditions. The acetic acid concentration is selected to be 10% to 20%, the heat treatment temperature is 300° C. to 350° C., and the treatment time is 40 minutes to 60 minutes. The layered structure mineral is one, two or three of montmorillonite, vermiculite and mica; The preparation method of the microcapsules for cigarette paper flavoring comprises the following steps: S-11. Dissolving the flavor in a cosolvent to obtain a flavor solution; S-12. The porous silica was added to the flavor solution and incubated at 30°C to 45°C overnight to obtain a flavor-loaded solution; S-13. The flavor material loading solution was added to the sodium alginate solution, stirred at high speed, and then the chitosan solution was added, and stirring was continued to prepare a primary microcapsule solution; S-14. Disperse the powdered layered mineral evenly in the primary microcapsule solution and incubate at 30°C to 45°C overnight. S-15. Prepare polylactic acid into an emulsion, add it to the solution obtained in step S-14, stir, concentrate, and spray-dry to obtain microcapsules.

2. The microcapsule for cigarette paper flavoring according to claim 1, characterized in that: In the first wall material, the mass ratio of sodium alginate to chitosan is 3:0.5-0.

8.

3. The microcapsule for cigarette paper flavoring according to claim 1, characterized in that: The mass ratio of the flavor material to the porous silica is 2-3:

1.

4. The microcapsule for cigarette paper flavoring according to claim 1, characterized in that: The particle size of the porous silica is 0.5 μm to 2 μm.

5. The method for using the microcapsules for flavoring cigarette paper according to claim 1, wherein: It is added to the cigarette paper in a form not coated on the surface of the cigarette paper.

6. A cigarette paper, characterized in that: The invention comprises the microcapsules according to any one of claims 1 to 4.

7. A cigarette, characterized in that: The invention comprises the microcapsules according to any one of claims 1 to 4.

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