Tobacco sheet containing double-layered flavor microcapsules and method for preparing the same

Abstract

This invention relates to the field of tobacco sheet technology, and more particularly to a tobacco sheet containing double-layer flavor microcapsules and its preparation method. The preparation method includes the following steps: preparing double-layer flavor microcapsules with a wax coating, the wax melting temperature being 40–70 °C; mixing tobacco raw materials, binders, and double-layer flavor microcapsules under high-speed shearing to obtain a dry mixture; the high-speed shearing is performed with a stirrer frequency of 25–35 Hz and a shearing blade frequency of 25–35 Hz for 15–25 s; the mass of the double-layer flavor microcapsules is 15%–25% of the mass of the tobacco raw materials; preparing a water suspension from woody raw materials, and then mixing it with binders and atomizing agents to obtain a wet mixture; spraying the wet mixture into the dry mixture under high-speed shearing to obtain a compound; and then rolling to obtain a tobacco sheet. This invention can improve the tensile strength of the tobacco sheet and reduce its viscosity while reducing the amount of woody raw materials used to ensure sensory quality.

Description

Technical Field

[0001] This invention relates to the field of tobacco sheet technology, and more particularly to a tobacco sheet containing double-layer flavor microcapsules and its preparation method. Background Technology

[0002] Tobacco sheets (also known as reconstituted tobacco) are a core recycled material in the tobacco industry. They are made from processing byproducts such as tobacco stems, tobacco dust, and broken tobacco leaves, which are reconstituted into homogeneous sheets through a process and used in cigarette formulations to reduce costs, improve quality, and reduce harm. At the same time, flavorings and fragrances are usually added to tobacco sheets to improve their sensory quality.

[0003] Patent document CN118716667A discloses a method for preparing roll-pressed sheets, comprising the following steps: defiberizing fibers to obtain fiber powder; pulverizing tobacco raw materials to obtain pulverized tobacco raw materials; mixing fiber powder, pulverized tobacco raw materials, and adhesive to obtain dry material; mixing water, atomizing agent, adhesive, and flavoring to obtain wet material; mixing dry material and wet material, roll-pressing, drying, and shredding to obtain roll-pressed sheets.

[0004] First, this existing technology improves the tensile strength of the product by adding dry fiber (5%–25%). However, as the table shows, when the proportion of outer fiber is high (over 15%), the natural tobacco aroma weakens and the woody smell becomes more pronounced. Conversely, when the proportion of outer fiber is low (5%–15%), while sensory quality is guaranteed, the problem of needle sticking occurs, meaning the tobacco sheet becomes soft and sticky. Therefore, the tobacco sheet produced by this existing technology cannot achieve a balance between high tensile strength, excellent anti-needle sticking performance, and good sensory quality. Second, the flavorings and fragrances are directly mixed with other components and then rolled. However, the high temperature and humidity environment during tobacco sheet processing, storage, and transportation makes the flavorings and fragrances prone to volatilization and loss, also affecting the sensory quality of the tobacco sheet.

[0005] Therefore, there is an urgent need to provide a tobacco sheet and its preparation method that ensures that the flavoring and fragrance are not easily lost and that also meets the requirements for tensile strength, sensory quality and anti-sticking properties. Summary of the Invention

[0006] The present invention aims to solve the above-mentioned problems by providing a tobacco sheet containing double-layer flavor microcapsules that does not easily lose flavor and fragrance, and simultaneously meets the requirements of tensile strength, sensory quality and anti-sticking properties, as well as its preparation method.

[0007] The technical solution to the problem solved by this invention is, firstly, to provide a method for preparing tobacco sheets containing double-layer flavor microcapsules, comprising the following steps:

[0008] S1. Preparation of double-layer fragrance microcapsules: after mixing fragrance with wall material, spray drying is performed to obtain particles, and then wax is coated on the surface of the particles to obtain double-layer fragrance microcapsules; the melting temperature of the wax is 40-70 ℃;

[0009] S2. Preparation of tobacco sheets:

[0010] S21. Under high-speed shearing, tobacco raw materials, binder, and the double-layer flavor microcapsules obtained in step S1 are mixed to obtain a dry mixture; the high-speed shearing in step S21 is as follows: stirrer frequency 25-35 Hz, shearing blade frequency 25-35 Hz; high-speed shearing for 15-25 s; the mass of the double-layer flavor microcapsules is 15%-25% of the mass of the tobacco raw materials;

[0011] S22. After preparing the wood raw material into an aqueous suspension, it is mixed with an adhesive and an atomizing agent to obtain a wet mixture;

[0012] S23. Under high-speed shearing, the wet mixture is sprayed into the dry mixture to obtain a mixture;

[0013] S24. The mixture is rolled to obtain tobacco sheets.

[0014] In this invention, flavor microcapsules coated with wax of appropriate melting point are used as dry materials to replace traditional flavorings, while woody raw materials are made into a suspension as wet materials. By combining appropriate shearing parameters and mixing steps, tobacco sheets are prepared. This method can reduce the amount of woody raw materials used to ensure sensory quality, improve the tensile strength of tobacco sheets, and reduce viscosity. In addition, it can effectively avoid the loss of flavorings and further improve the sensory quality of tobacco sheets.

[0015] Specifically first The process involves mixing wax-coated flavor microcapsules, a portion of the binder, and tobacco raw materials. Under high-speed shearing, the wax and binder undergo micro-melting, causing the dry materials to form loose aggregates. Due to the relatively large amount of tobacco raw materials used, the structure of these aggregates consists of multiple tobacco particles adhering to a single flavor microcapsule. Therefore, firstly, the high-speed shearing parameters and the melting point of the wax need to be limited. Micro-melting is achieved through appropriate collision and friction while avoiding damage to the flavor microcapsules. The wax melting temperature is between 40 and 70 °C, the stirrer frequency is 25–35 Hz, the shearing blade frequency is 25–35 Hz, and the high-speed shearing time is 15–25 s. Secondly, the ratio of tobacco raw materials to the double-layered flavor microcapsules needs to be limited, with the mass of the double-layered flavor microcapsules being 15%–25% of the mass of the tobacco raw materials.

[0016] SecondlyThe wood raw materials are no longer used as dry materials, but are made into a suspension before being added. This suspension is separated from the wax-coated fragrance microcapsules, preventing the wax-coated fragrance microcapsules from preferentially adsorbing and agglomerating with the wood raw materials (the surface of wood fibers is rougher and has hydrophobic areas), which would hinder the entanglement between wood fibers and affect tensile strength. At the same time, in the wet mixing process, the wood raw materials fully absorb moisture and atomizing agents, causing the wood fibers to swell and become soft, and further reducing woody odor.

[0017] Secondly When the wet blend is sprayed onto the dry blend, the sprayed droplets are preferentially absorbed by the outer layer of tobacco raw material in the dry blend agglomerates because the wax is hydrophobic and the tobacco fiber is hydrophilic. Then, the softened wood fibers in the droplets spread out and evenly wrap around the outer surface of the agglomerates. This makes the wood fibers form a continuous and soft fiber network that covers the agglomerates. Finally, an overall structure is formed that is approximately from the inside out: microcapsules - tobacco fibers - a wood fiber network that absorbs atomizing agents.

[0018] at last When this monolithic structure is rolled, the heat generated by high pressure and friction causes the wax on the surface of the microcapsules to melt again. Simultaneously, under rolling pressure, the internal wax penetrates outward, filling the spaces between tobacco particles and bonding the tobacco particles and wood fiber network in the radial direction. This replaces the woody raw materials and adhesives in its filling and bonding function, thus reducing the amount of woody raw materials and adhesives used and improving the sensory quality and tackiness of the tobacco sheet. Also under rolling pressure, not only do the wood fiber networks of adjacent monolithic structures further contact and entangle with each other, but the wood fiber networks in individual monolithic structures also contact and entangle with the tobacco fibers radially inward, effectively improving the tensile strength of the tobacco sheet.

[0019] Based on this, the technical solution of the present invention was completed.

[0020] Step S1 is used to prepare double-layer fragrance microcapsules. The significance of the double layer is that the fragrance will not leak when the outermost wax melts slightly, while effectively improving its resistance to high temperature and high humidity.

[0021] Flavorings are not restricted; for example, they can be peppermint flavoring. The main component of peppermint flavoring is menthol. Peppermint flavoring provides a strong minty flavor and a cooling sensation, and has high volatility and low water solubility. When used in heated cigarettes, it can impart a cooling taste, reduce tobacco irritation, and enrich the aroma layers.

[0022] The wall material should possess sufficient strength to prevent cracking under high-speed shearing. Preferably, the wall material is composed of modified starch, maltodextrin, and gum arabic. The three are combined, with the modified starch forming the main body of the wall material, creating a continuous, flexible three-dimensional network to absorb impact; the maltodextrin filling the gaps in the three-dimensional network to increase the density of the wall material; and the gum arabic improving the surface smoothness of the wall material and reducing stress concentration points. Preferably, the modified starch is selected from at least one of octenyl succinic acid starch, hydroxypropyl starch, and hydroxymethyl starch.

[0023] The amounts of flavoring and wall material are preferably limited. Excessive flavoring can cause the wall material to crack, while excessive wall material can affect the release of aroma. Preferably, according to the present invention, the flavoring is 14-18 parts by weight, and the wall material comprises 25-40 parts modified starch, 6-12 parts maltodextrin, and 0.5-1.5 parts gum arabic. For example, the flavoring can be 14, 15, 16, 17, 18, 19, or 20 parts; the modified starch can be 25, 30, 35, or 40 parts; the maltodextrin can be 6, 8, 10, or 12 parts; and the gum arabic can be 0.5, 1, or 1.5 parts.

[0024] During preparation, water is usually added to ensure uniform dispersion of the components. Preferably, the invention further includes 36 to 48 parts by weight of water. Examples include 36, 38, 40, 42, 44, 46, and 48 parts.

[0025] The fragrance and wall material are mixed and homogenized in water. Preferably, the homogenization time is 10–25 min, and the speed is 3500–8000 rpm. For example, the homogenization time can be 10 min, 15 min, 20 min, or 25 min; the speed can be 3500 rpm, 4000 rpm, 4500 rpm, 5000 rpm, 5500 rpm, 6000 rpm, 6500 rpm, 7000 rpm, 7500 rpm, or 8000 rpm.

[0026] After homogenization, the product is spray-dried to obtain particles. Preferably, the inlet air temperature for spray drying is 160–190°C, and the outlet air temperature is 90–120°C. For example, the inlet air temperature can be 160°C, 170°C, 180°C, or 190°C; and the outlet air temperature can be 90°C, 100°C, 110°C, or 120°C.

[0027] The melting temperature of the wax is between 40 and 70 °C, preferably food-grade wax. As a preferred embodiment of the present invention, the wax is selected from at least one of coconut wax, soybean wax, and white beeswax.

[0028] The amounts of granules and wax are preferably limited. Insufficient wax will not provide enough filling and bonding during rolling; excessive wax will easily form a continuous phase, leading to increased stickiness of the tobacco sheet. Preferably, the mass ratio of granules to wax is (1-3):1. Examples include 1:1, 1.5:1, 2:1, 2.5:1, and 3:1.

[0029] The method of applying wax to the surface of the particles is not limited; for example, the wax is melted and then sprayed onto the surface of the particles.

[0030] Step S21 is used to prepare a dry mix, forming an aggregate with double-layered flavor microcapsules inside and tobacco raw materials outside.

[0031] The tobacco raw materials are not limited. For example, they can be obtained by crushing at least one of tobacco leaves, tobacco stems, and tobacco dust, with an average particle size of 40 to 70 μm, preferably 50 μm.

[0032] The adhesive is not limited, but for example, it may be selected from at least one of carboxymethyl cellulose, sodium alginate, guar gum, and chitosan, preferably carboxymethyl cellulose.

[0033] The mass of the double-layer flavor microcapsule is 15% to 25% of the mass of the tobacco raw material; for example, it can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, or 25%.

[0034] The amount of binder used in the dry mix is ​​not limited. Due to the use of wax, its amount can be reduced. As a preferred embodiment of the present invention, the mass of the binder used in step S21 is 1% to 2% of the mass of the tobacco raw material; for example, it can be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2%.

[0035] High-speed shearing dry mixing is performed, where the agitator frequency is 25–35 Hz, the shearing blade frequency is 25–35 Hz, and the high-speed shearing time is 15–25 s. For example, the agitator frequency can be 25 Hz, 26 Hz, 27 Hz, 28 Hz, 29 Hz, 30 Hz, 31 Hz, 32 Hz, 33 Hz, 34 Hz, or 35 Hz; the shearing blade frequency can be 25 Hz, 26 Hz, 27 Hz, 28 Hz, 29 Hz, 30 Hz, 31 Hz, 32 Hz, 33 Hz, 34 Hz, or 35 Hz; and the time can be 15 s, 16 s, 17 s, 18 s, 19 s, 20 s, 21 s, 22 s, 23 s, 24 s, or 25 s.

[0036] Step S22 is used to prepare a wet mixture and to allow the wood fibers to fully absorb water and atomizing agent.

[0037] The type of wood raw material is not limited; for example, softwood pulpboard is used. The method of preparing the wood raw material into an aqueous suspension is not limited; for example, softwood pulpboard is added to water and disintegrated using a hydraulic pulper to obtain a wood pulp suspension. The amounts of wood raw material and water are preferably limited to ensure uniform dispersion of the wood fibers. Preferably, the mass of the wood raw material is 1% to 7% of the water; for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, or 7%.

[0038] The atomizing agent is not restricted; for example, glycerin can be used.

[0039] The adhesive used in step S22 is consistent with that used in step S21.

[0040] As described above, the amount of wood raw material used can be reduced. Preferably, the mass of the wood raw material is 0.5% to 3% of the mass of the tobacco raw material. For example, it can be 0.5%, 0.75%, 1%, 1.25%, 1.5%, 1.75%, 2%, 2.25%, 2.5%, 2.75%, or 3%.

[0041] There is no limit to the amount of atomizing agent used. For example, the mass of the atomizing agent is generally 15% to 30% of the tobacco raw material, such as 15%, 20%, 25%, or 30%.

[0042] The amount of adhesive used in wet mixing does not need to be excessive, just enough to assist the wood raw material in absorbing the atomizing agent. As a preferred embodiment of the present invention, the mass of the adhesive used in step S22 is 1% to 2% of the mass of the atomizing agent; for example, it can be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2%.

[0043] When wet mixing, it is preferable to first mix and disperse the atomizing agent and the adhesive evenly, and then mix them with the aqueous suspension of the wood raw material.

[0044] Step S23 is used for wet granulation to form an overall structure consisting of microcapsules, tobacco fibers, and a network of wood fibers that absorb atomizing agents, from the inside out.

[0045] The spraying speed of the wet blend is preferably limited. Too high a speed results in large droplet sizes, which easily penetrate aggregates and affect the filling of tobacco fibers with wax. Too low a speed results in droplets that easily disperse, are difficult to effectively wet, and cannot form the desired overall structure. Preferably, the spraying speed of the wet blend is 0.4–0.5 kg / s. Examples include 0.4 kg / s, 0.41 kg / s, 0.42 kg / s, 0.43 kg / s, 0.44 kg / s, 0.45 kg / s, 0.46 kg / s, 0.47 kg / s, 0.48 kg / s, 0.49 kg / s, and 0.5 kg / s.

[0046] At this point, the high-speed shearing parameters are preferably limited. Excessive shearing can easily break up agglomerates, while insufficient shearing can easily lead to uneven coating of the wet mixture. Preferably, the high-speed shearing in step S23 is as follows: agitator frequency of 35–45 Hz and shearing blade frequency of 45–55 Hz; after spraying, continue high-speed shearing for 3–8 minutes. For example, the agitator frequency can be 35 Hz, 36 Hz, 37 Hz, 38 Hz, 39 Hz, 40 Hz, 41 Hz, 42 Hz, 43 Hz, 44 Hz, or 45 Hz; the shearing blade frequency can be 45 Hz, 46 Hz, 47 Hz, 48 Hz, 49 Hz, 50 Hz, 51 Hz, 52 Hz, 53 Hz, 54 Hz, or 55 Hz; and the time can be 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, or 8 minutes.

[0047] Step S24 is used for roll forming. Since roll forming pressure is difficult to feedback, roll forming parameters are fed back by roll forming thickness.

[0048] As a preferred embodiment of the present invention, the roll forming adopts a six-stage tandem roll press, and the thickness of the sheet after each stage of roll forming is as follows: first stage 4-6 mm, second stage 3-4 mm, third stage 2-3 mm, fourth stage 1-2 mm, fifth stage 0.3-0.8 mm, and sixth stage 0.1-0.2 mm.

[0049] As a preferred embodiment of the present invention, the formed tobacco sheet has a thickness of 0.1 to 0.2 mm and a width of 400 to 800 mm.

[0050] Secondly, another object of the present invention is to provide a tobacco sheet containing double-layer flavor microcapsules prepared by the above-described method. This tobacco sheet possesses excellent tensile strength, sensory quality, and low viscosity.

[0051] The beneficial effects of this invention are:

[0052] 1. This invention provides a tobacco sheet containing double-layer flavor microcapsules and its preparation method. Flavor microcapsules coated with wax of appropriate melting point replace traditional flavorings and fragrances as dry materials, while woody raw materials are made into a suspension as wet materials. The tobacco sheet is prepared by combining appropriate shearing parameters and mixing steps. This method can improve the tensile strength of tobacco sheets and reduce viscosity while reducing the amount of woody raw materials used to ensure sensory quality.

[0053] 2. This invention can effectively avoid the loss of flavorings under high temperature and high humidity conditions during production, processing, storage and transportation, and further improve the sensory quality of tobacco sheets. Detailed Implementation

[0054] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments.

[0055] Example 1

[0056] A tobacco sheet containing double-layer flavor microcapsules is prepared by the following steps:

[0057] S1. Preparation of double-layer flavor microcapsules: According to the mass parts, 16 parts of peppermint flavor, 30 parts of octenyl succinic acid starch, 9 parts of maltodextrin, 1 part of gum arabic, and 44 parts of water are mixed and then homogenized at 6000 rpm for 20 min to obtain peppermint emulsion flavor; finally, the peppermint emulsion is spray-dried to obtain peppermint microcapsule flavor particles, wherein the inlet air temperature of the spray drying equipment is 180 ℃ and the outlet air temperature is 95 ℃.

[0058] According to the mass ratio of peppermint microcapsule flavoring granules to white beeswax of 2:1, a certain amount of peppermint microcapsule flavoring granules are weighed out. During the stirring and rotation process, the melted white beeswax is sprayed onto the surface of the peppermint microcapsule flavoring granules through a spraying device to obtain double-layer peppermint microcapsules.

[0059] Double-layer peppermint microcapsule testing: 20 g of double-layer peppermint microcapsules were placed in 100 g of water and stirred for 3 min. The aroma of the solution was evaluated, and no peppermint aroma was emitted, indicating that the peppermint flavor was successfully encapsulated. 5 mg of double-layer peppermint microcapsules were placed in a solid crucible and sealed. Thermogravimetric analysis was performed under the conditions of an initial temperature of 30 ℃, an final temperature of 500 ℃, a heating rate of 10 ℃ / min, and a nitrogen flow rate of 20 mL / min. The maximum degradation temperature was 293 ℃, indicating that it can prevent the release of peppermint flavor in water-containing and high-temperature (100 ℃) processing environments, and is not easily released in high-temperature storage environments.

[0060] S2. Preparation of tobacco sheets:

[0061] S21. Tobacco fragments and tobacco dust are processed by an air jet mill to obtain tobacco powder with an average particle size of approximately 50 μm. The following materials are then fed into a high-speed shear mixer: 15 kg of tobacco powder, 0.225 kg of CMC binder powder, and 3 kg of the aforementioned double-layered menthol microcapsules; premixed for 20 seconds under conditions of a stirrer frequency of 30 Hz and a shear blade frequency of 30 Hz to obtain a dry mix.

[0062] S22. 0.17 kg of softwood pulp board was added to 4.7 kg of pure water and pulped using a hydraulic pulper to obtain a wood pulp suspension. 0.07 kg of CMC binder powder was added to 4 kg of glycerol and stirred evenly to obtain a CMC glycerol suspension. The wood pulp suspension was then added to the CMC glycerol suspension and stirred evenly to obtain a wet mixture.

[0063] S23. Wet mixture is sprayed into a high-speed shear press filled with dry mixture at a spraying speed of 0.45 kg / s. During spraying, the agitator frequency is increased to 40 Hz and the shear blade frequency is increased to 50 Hz. After spraying, these parameters are maintained for 4 minutes to continue mixing, yielding a wet-granulated mixture. The ratio of tobacco raw material: double-layer menthol microcapsules: woody raw material: binder: atomizing agent is 100:20:1.1:2:26.7.

[0064] S24. The mixture is fed into a six-stage tandem roller press for roll forming. The sheet thicknesses after each stage of roll forming are: stage 1, 5 mm; stage 2, 3.5 mm; stage 3, 2.53 mm; stage 4, 1.5 mm; stage 5, 0.5 mm; and stage 6, 0.16 mm. A continuous tobacco sheet with a thickness of 0.16 mm and a width of 600 mm is obtained. The sheet roll forming process is smooth, with no significant material sticking to the rollers.

[0065] The sheets were then dried in a belt oven to a wet basis moisture content of 6%. Finally, the dried sheets were cut into filaments with a length of 30 mm and a width of 1 mm.

[0066] The content of menthol in the tobacco sheet was 22.9 mg / g; the RSD of the distribution uniformity of menthol in the tobacco sheet was 4.20%.

[0067] Example 2

[0068] This embodiment is basically the same as embodiment 1, except that the amount of double-layered peppermint microcapsules is different.

[0069] Specifically, in step S21, the following materials are fed into the high-speed shear mixer: 15 kg of tobacco powder, 0.225 kg of CMC binder powder, and 2.25 kg of the double-layered menthol microcapsules prepared above.

[0070] Example 3

[0071] This embodiment is basically the same as embodiment 1, except that the amount of double-layered peppermint microcapsules is different.

[0072] Specifically, in step S21, the following materials are fed into the high-speed shear mixer: 15 kg of tobacco powder, 0.225 kg of CMC binder powder, and 3.75 kg of the double-layered peppermint microcapsules prepared above.

[0073] Example 4

[0074] This embodiment is basically the same as Embodiment 1, except that the high-speed shearing parameters are different during dry mixing.

[0075] Specifically, in step S21, the mixture is premixed for 15 seconds under the conditions of a stirrer frequency of 25 Hz and a shear blade frequency of 25 Hz.

[0076] Example 5

[0077] This embodiment is basically the same as Embodiment 1, except that the high-speed shearing parameters are different during dry mixing.

[0078] Specifically, in step S21, the mixture is premixed for 25 seconds under the conditions of a stirrer frequency of 35 Hz and a shear blade frequency of 35 Hz.

[0079] Example 6

[0080] This embodiment is basically the same as embodiment 1, except that the wall material is different; the wall material is only octenyl succinic acid starch.

[0081] Specifically, in step S1, 16 parts of peppermint flavoring, 40 parts of octenyl succinic acid starch, and 44 parts of water are mixed according to the mass ratio, and then homogenized at 6000 rpm for 20 min to obtain peppermint emulsion flavoring.

[0082] Example 7

[0083] This embodiment is basically the same as Embodiment 1, except that the mass ratio of peppermint microcapsule flavoring particles to white beeswax is different; the amount of peppermint microcapsule flavoring particles is kept constant, while the amount of white beeswax is increased.

[0084] Specifically, in step S1, a certain amount of peppermint microcapsule flavoring particles are weighed according to a mass ratio of 2:2 to white beeswax. During the stirring and rotation process, the molten white beeswax is sprayed onto the surface of the peppermint microcapsule flavoring particles through a spraying device to obtain double-layer peppermint microcapsules.

[0085] Example 8

[0086] This embodiment is basically the same as Embodiment 1, except that the mass ratio of peppermint microcapsule flavoring particles to white beeswax is different; the amount of peppermint microcapsule flavoring particles is kept constant, while the amount of white beeswax is reduced.

[0087] Specifically, in step S1, a certain amount of peppermint microcapsule flavoring particles are weighed according to the mass ratio of peppermint microcapsule flavoring particles to white beeswax 2:0.67. During the stirring and rotation process, the molten white beeswax is sprayed onto the surface of the peppermint microcapsule flavoring particles through a spraying device to obtain double-layer peppermint microcapsules.

[0088] Example 9

[0089] This embodiment is basically the same as Embodiment 1, except that the amount of adhesive used in the dry mix is ​​different.

[0090] Specifically, in step S21, the following materials are fed into the high-speed shear mixer: 15 kg of tobacco powder, 0.150 kg of CMC binder powder, and 3 kg of the prepared double-layer peppermint microcapsules.

[0091] Example 10

[0092] This embodiment is basically the same as Embodiment 1, except that the amount of adhesive used in the dry mix is ​​different.

[0093] Specifically, in step S21, the following materials are added to the high-speed shear mixer: 15 kg of tobacco powder, 0.300 kg of CMC binder powder, and 3 kg of the prepared double-layer peppermint microcapsules.

[0094] Example 11

[0095] This embodiment is basically the same as Embodiment 1, except that the amount of wood raw material used is different.

[0096] Specifically, in step S22, 0.3 kg of softwood pulp board is added to 4.7 kg of pure water and decomposed using a hydraulic pulper to obtain a wood pulp suspension.

[0097] Example 12

[0098] This embodiment is basically the same as Embodiment 1, except that the amount of wood raw material used is different.

[0099] Specifically, in step S22, 0.075 kg of softwood pulp board is added to 4.7 kg of pure water and decomposed using a hydraulic pulper to obtain a wood pulp suspension.

[0100] Example 13

[0101] This embodiment is basically the same as Embodiment 1, except that the rolling parameters are different.

[0102] Specifically, in step S24, the mixture is fed into a six-stage tandem roller press for roll forming. The thickness of the sheet after each stage of roll forming is as follows: 6 mm for the first stage, 4 mm for the second stage, 3 mm for the third stage, 2 mm for the fourth stage, 0.8 mm for the fifth stage, and 0.2 mm for the sixth stage.

[0103] Example 14

[0104] This embodiment is basically the same as Embodiment 1, except that the rolling parameters are different.

[0105] Specifically, in step S24, the mixture is fed into a six-stage tandem roller press for roll forming. The thickness of the sheet after each stage of roll forming is as follows: 4 mm for the first stage, 3 mm for the second stage, 2 mm for the third stage, 1 mm for the fourth stage, 0.3 mm for the fifth stage, and 0.14 mm for the sixth stage.

[0106] Comparative Example 1

[0107] This comparative example is basically the same as Example 1, except that it does not have a wax coating process.

[0108] Specifically, in step S21, the following materials are added to the high-speed shear mixer: 15 kg of tobacco powder, 0.225 kg of CMC binder powder, and 3 kg of uncoated peppermint microcapsule flavoring granules obtained in step S1 of Example 1; the mixture is premixed for 20 seconds under the conditions of a stirrer frequency of 30 Hz and a shear blade frequency of 30 Hz to obtain a dry mix.

[0109] Comparative Example 2

[0110] This comparative example is basically the same as Example 1, except that the wood material is added in the form of dry mix.

[0111] Specifically: S21. Tobacco fragments and tobacco dust are processed using an air jet mill to obtain tobacco powder with an average particle size of approximately 50 μm. Softwood pulp boards are pulverized into wood flour using an air jet mill. The following materials are added to a high-speed shear mixer: 15 kg tobacco powder, 0.225 kg CMC binder powder, 3 kg double-layer menthol microcapsules, and 0.17 kg wood flour; premixed for 20 seconds under conditions of a stirrer frequency of 30 Hz and a shear blade frequency of 30 Hz; a dry mix is ​​obtained.

[0112] S22. Add 0.07 kg of CMC binder powder and 4 kg of glycerin to 4.7 kg of pure water, stir evenly to obtain a wet mixture.

[0113] S23. Inject the wet mixture into a high-speed shear press filled with dry mixture at a spraying speed of 0.45 kg / s. During the spraying process, increase the agitator frequency to 40 Hz and the shear blade frequency to 50 Hz. After spraying is complete, maintain these parameters and continue mixing for 4 minutes to obtain the wet-granulated mixture.

[0114] S24. The mixture is fed into a six-stage tandem roller press for rolling. The thickness of the sheet after each stage of rolling is as follows: stage 1, 5 mm; stage 2, 3.5 mm; stage 3, 2.53 mm; stage 4, 1.5 mm; stage 5, 0.5 mm; and stage 6, 0.16 mm, resulting in continuous tobacco sheets. Subsequently, the sheets are dried in a belt oven to a wet basis moisture content of 6%. Finally, the dried sheets are cut into shreds with a length of 30 mm and a width of 1 mm.

[0115] Comparative Example 3

[0116] This comparative example is basically the same as Example 1, except that the amount of double-layered peppermint microcapsules used is excessive.

[0117] Specifically, in step S21, the following materials are added to the high-speed shear mixer: 15 kg of tobacco powder, 0.225 kg of CMC binder powder, and 5 kg of double-layer peppermint microcapsules.

[0118] Comparative Example 4

[0119] This comparative example is basically the same as Example 1, except that there is insufficient shearing during dry mixing.

[0120] Specifically, in step S21, the mixture is premixed for 20 seconds under the conditions of a stirrer frequency of 15 Hz and a shear blade frequency of 15 Hz.

[0121] Testing and Evaluation

[0122] The evaluation of the roll forming process of the examples and comparative examples is shown in Table 3 below; the evaluation of the tensile strength and sensory quality of the tobacco sheets obtained in the examples and comparative examples is shown in Table 1 below.

[0123] Table 1.

[0124] Example Evaluation of roll forming process Tensile strength (kN / m) Sensory quality evaluation Example 1 No sticking rollers, no sticking scrapers 0.193 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 2 No sticking rollers, no sticking scrapers 0.227 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 3 No sticking rollers, no sticking scrapers 0.162 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 4 No sticking rollers, no sticking scrapers 0.197 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 5 No sticking rollers, no sticking scrapers 0.218 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 6 No sticking to rollers or scrapers, slight breakage. 0.170 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 7 Slight sticking to rollers, no sticking to scraper 0.180 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 8 No sticking rollers, no sticking scrapers 0.191 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 9 No sticking rollers, no sticking scrapers 0.173 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 10 No sticking rollers, no sticking scrapers 0.222 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 11 No sticking rollers, no sticking scrapers 0.231 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 12 No sticking rollers, no sticking scrapers 0.141 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 13 No sticking rollers, no sticking scrapers 0.259 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Example 14 No sticking rollers, no sticking scrapers 0.129 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Comparative Example 1 Slight sticking to rollers and scrapers, and loss of the minty scent on site. 0.188 It has a moderate minty aroma, no woody notes, and no sticky feeling in the mouth. Comparative Example 2 No sticking rollers or scrapers, resulting in uneven sheet thickness and the presence of white cores. 0.186 Strong minty aroma, slight woody notes, no sticky feeling in the mouth Comparative Example 3 No sticking rollers or scrapers cause material to stick, resulting in severe breakage. 0.137 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth. Comparative Example 4 No sticking rollers or scrapers, resulting in uneven sheet thickness and the presence of tiger stripes. 0.178 It has a strong minty aroma, no woody notes, and no sticky feeling in the mouth.

[0125] As can be seen from Table 1, the tobacco sheets prepared by the method of the present invention can simultaneously meet the requirements of tensile strength, sensory quality and anti-sticking properties.

[0126] In Comparative Example 1, the lack of a wax coating layer prevented the physical reinforcement effect of the micro-melted wax, resulting in a significant reduction in tensile strength. At the same time, the lack of wax layer protection made it easy for the peppermint flavor to be lost during the preparation process, and the surface of the single-layer microcapsules was prone to absorbing water and becoming sticky, which had an adverse effect on the anti-sticking properties and sensory quality of the tobacco sheet.

[0127] In Comparative Example 2, the woody raw materials were added in a dry-mixed form, which prevented them from fully absorbing moisture and atomizing agents beforehand. This resulted in a pronounced woody aroma in the tobacco sheets, affecting sensory quality. Simultaneously, the double-layered microcapsules preferentially adhered to the woody raw materials, negatively impacting fiber entanglement and reducing tensile strength. In contrast, in this invention, the woody raw materials are wet-mixed and sprayed onto the dry-mixed material. This allows the woody fibers to pre-spread and entangle to form a pre-fiber network, which then indirectly contacts the wax under roller pressing. Furthermore, wet granulation provides insufficient absorption time for the remaining binder and atomizing agent, leading to uneven sheets and the presence of white cores.

[0128] In Comparative Example 3, the excessive amount of double-layered menthol microcapsules caused the tobacco particles to be separated by the double-layered menthol microcapsules, which in turn led to a decrease in tensile strength.

[0129] In Comparative Example 4, insufficient shearing during dry mixing failed to effectively assist in the micro-melting of the wax on the surface of the microcapsules. This resulted in the tobacco powder and the double-layer menthol microcapsules being simply mixed, which in turn caused the tobacco powder and microcapsules to easily slip relative to each other during subsequent rolling. The wax could not be effectively filled and bonded, resulting in uneven tobacco sheets with tiger stripes.

[0130] Furthermore, the comparison within the examples demonstrates that appropriately adjusting the parameters in the preparation method can further improve the quality of the tobacco sheet.

[0131] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method for preparing tobacco sheets containing double-layer flavor microcapsules, characterized in that: Includes the following steps: S1. Preparation of double-layer fragrance microcapsules: after mixing fragrance with wall material, spray drying is performed to obtain particles, and then wax is coated on the surface of the particles to obtain double-layer fragrance microcapsules; the melting temperature of the wax is 40-70℃; S2. Preparation of tobacco sheets: S21. Under high-speed shearing, tobacco raw materials, binder, and the double-layer flavor microcapsules obtained in step S1 are mixed to obtain a dry mixture; the high-speed shearing in step S21 is as follows: stirrer frequency 25-35 Hz, shearing blade frequency 25-35 Hz; high-speed shearing for 15-25 s; the mass of the double-layer flavor microcapsules is 15%-25% of the mass of the tobacco raw materials; S22. After preparing the wood raw material into an aqueous suspension, it is mixed with an adhesive and an atomizing agent to obtain a wet mixture; S23. Under high-speed shearing, the wet mixture is sprayed into the dry mixture to obtain a mixture; S24. The mixture is rolled to obtain tobacco sheets.

2. The method for preparing tobacco sheets containing double-layer flavor microcapsules according to claim 1, characterized in that: The wall material is composed of modified starch, maltodextrin, and gum arabic.

3. The method for preparing tobacco sheets containing double-layer flavor microcapsules according to claim 2, characterized in that: The flavoring is 14-18 parts by weight, and the wall material comprises 25-40 parts modified starch, 6-12 parts maltodextrin, and 0.5-1.5 parts gum arabic.

4. The method for preparing tobacco sheets containing double-layer flavor microcapsules according to claim 1, characterized in that: The mass ratio of the particles to the wax is (1-3):

1.

5. The method for preparing tobacco sheets containing double-layer flavor microcapsules according to claim 1, characterized in that: The mass of the wood raw material is 0.5% to 3% of the mass of the tobacco raw material.

6. The method for preparing tobacco sheets containing double-layer flavor microcapsules according to claim 1, characterized in that: The total mass of the adhesive is 1% to 3% of the mass of the tobacco raw material.

7. The method for preparing tobacco sheets containing double-layer flavor microcapsules according to claim 1, characterized in that: In step S23, the injection rate of the wet mixture is 0.4–0.5 kg / s.

8. A method for preparing tobacco sheets containing double-layer flavor microcapsules according to claim 1 or 7, characterized in that: The high-speed shearing in step S23 is as follows: the stirrer frequency is 35-45 Hz, and the shearing blade frequency is 45-55 Hz; after the liquid spraying is completed, high-speed shearing continues for 3-8 minutes.

9. The method for preparing tobacco sheets containing double-layer flavor microcapsules according to claim 1, characterized in that: In step S24, the roll forming adopts a six-stage tandem roll press, and the thickness of the sheet after each stage of roll forming is: 4-6 mm for the first stage, 3-4 mm for the second stage, 2-3 mm for the third stage, 1-2 mm for the fourth stage, 0.3-0.8 mm for the fifth stage, and 0.1-0.2 mm for the sixth stage.

10. A tobacco sheet containing double-layer flavor microcapsules prepared by the preparation method according to any one of claims 1 to 9.