Functional heating cigarette reconstituted tobacco and preparation method thereof

Abstract

The application discloses functional heating cigarette reconstituted tobacco and a preparation method thereof, and relates to the technical field of tobacco. The reconstituted tobacco comprises a fiber base material layer, a smoke-generating layer, a flavor modifying layer and a temperature-induced permeation protection layer which are sequentially compounded on the surface of the fiber base material layer from inside to outside. The smoke-generating layer comprises tobacco extract, polyhydric alcohol smoke-generating agent and stabilizer. The flavor modifying layer comprises a flavoring system. The temperature-induced permeation protection layer is arranged to block the escape of aroma and the invasion of moisture at normal temperature, and to form a porous structure by thermal decomposition to release aroma when heated to 240-300 DEG C. The application sequentially compounds the smoke-generating layer, the flavor modifying layer and the temperature-induced permeation protection layer on the surface of the fiber base material layer from inside to outside, and makes the temperature-induced permeation protection layer block the escape of aroma and the invasion of moisture at normal temperature, and form a porous structure by thermal decomposition to release aroma when heated to 240-300 DEG. Thus, the problem of contradiction between the easy loss of aroma, moisture resistance and aroma release function in the existing adsorption type aroma locking technology is fundamentally solved.

Description

Technical Field

[0001] This invention relates to the field of tobacco technology, specifically to a functional heated cigarette reconstituted tobacco leaf and its preparation method. Background Technology

[0002] Heated cigarettes, also known as low-temperature cigarettes, do not ignite tobacco with an open flame. Instead, they use electric heating or charcoal combustion smoke to heat the tobacco matrix, causing the atomizing medium, aroma components, and added flavorings in the tobacco matrix to volatilize and produce smoke similar to that of traditional cigarettes. This allows consumers to achieve the same physiological satisfaction as smoking traditional cigarettes, while releasing fewer harmful substances, thus gaining popularity among consumers. Reconstituted tobacco is the core material of heated cigarette products, and its sensory quality, smoke stability, and aroma retention directly determine the consumer experience and product shelf life.

[0003] Coating is the mainstream process for the large-scale production of reconstituted tobacco leaves for heated cigarettes. This process involves coating functional components such as tobacco extracts, smoking agents, and flavorings onto the surface of a plant fiber substrate, followed by drying to obtain reconstituted tobacco leaves with stable smoking performance and flavor characteristics. However, there are still several technical bottlenecks in the actual production and application of reconstituted tobacco leaves for heated cigarettes prepared by the existing coating method: (1) Volatile components such as flavorings are easily lost during subsequent drying, storage and transportation, resulting in significant aroma decay and difficulty in maintaining characteristic aromas stably for a long time. (2) Traditional moisture-proof treatments often use physical barrier layers formed by hydrophobic polymer materials. Although these can delay the product's moisture absorption to a certain extent, the dense barrier layer will significantly hinder the normal release of aroma under heating conditions, causing a contradiction between moisture-proof and aroma-releasing functions.

[0004] In recent years, research in the industry has attempted to improve the aroma retention of reconstituted tobacco leaves through "fiber gel aroma locking" technology. This type of technology mainly utilizes the three-dimensional network structure of gel materials to physically adsorb or hydrogen bond aroma components to achieve retention. However, this adsorption-based aroma locking mechanism has inherent limitations: adsorption has saturation, and the shift in the adsorption-desorption equilibrium during long-term storage leads to slow aroma loss; the open pore structure of the gel network cannot completely prevent the diffusion and escape of small molecule aroma components at room temperature; and the aroma locking and loading functions are concentrated in the same material layer, making it difficult to simultaneously meet the dual requirements of moisture protection and aroma release. Therefore, existing technologies have not yet resolved the contradiction between moisture protection and aroma release functions, and there is a lack of a functional reconstituted tobacco leaf structure that can effectively lock aroma at room temperature and accurately release aroma upon heating.

[0005] It should be noted that although multi-layer coating structures exist in existing technologies (such as Chinese patent CN110537721B), which utilizes a combination of spray coating and slot extrusion coating techniques for multiple, multi-stage coatings, the functional design of each layer remains at the level of physical superposition: each coating layer is a conventional mixture of tobacco extracts, smoke-generating agents, and flavorings. There is a lack of in-depth design for functional synergy and material matching between layers, and no protective layer specifically designed for aroma locking, moisture protection, and thermo-permeable release is involved. Therefore, while multi-layer coating processes exist in existing technologies, they lack in-depth design for functional synergy and material matching between layers, and do not involve the technical concept of achieving thermo-permeable aroma release through material thermal decomposition. Therefore, it is necessary to develop a functional heated cigarette reconstituted tobacco leaf through material and structural innovation, simultaneously achieving the triple functions of moisture protection, aroma locking, and aroma release. Summary of the Invention

[0006] The purpose of this invention is to provide a functional reconstituted tobacco leaf for heated cigarettes and its preparation method. By sequentially compounding a smoke-generating layer, a flavor-modifying layer, and a thermosensitive protective layer on the surface of a fiber substrate layer from the inside out, the thermosensitive protective layer can prevent aroma loss and moisture intrusion at room temperature, and thermally decompose to form a porous structure to release aroma when heated to 240~300℃. This solves the technical problem that the aroma of reconstituted tobacco leaves for heated cigarettes is easily lost during storage and transportation, and that the moisture-proof and aroma-releasing functions are contradictory.

[0007] To solve the above-mentioned technical problems, in a first aspect, embodiments of the present invention provide a functional heated cigarette reconstituted tobacco leaf, comprising a fiber substrate layer and a smoke-generating layer, a flavor modification layer, and a thermosensitive protective layer sequentially compounded on the surface of the fiber substrate layer from the inside out; The smoke-generating layer contains tobacco extract, polyol smoke-generating agent, and stabilizer; The flavor-modifying layer comprises a flavoring and fragrance system; The thermosensitive protective layer is designed to prevent aroma loss and moisture intrusion at room temperature, and to thermally decompose to form a porous structure when heated to 240~300℃ to release aroma.

[0008] Unlike existing technologies where multilayer coatings only achieve physical superposition, the three-layer structure of this invention has a clear functional synergy: The smoke-generating layer provides the natural aroma of tobacco and the basis for smoke generation, providing the main aroma source for the entire reconstituted tobacco leaf; The flavor modification layer carries characteristic flavorings and fragrances, giving the product a personalized flavor. The temperature-sensitive transparent protective layer utilizes the dense structure of the alginate-divalent metal ion cross-linking network at room temperature to physically exclude aroma molecules in the flavor modification layer, preventing them from escaping outwards and blocking external moisture from penetrating inwards. When heated to 240~300℃, the cross-linking network undergoes thermal decomposition to form a porous structure, allowing the sealed aroma molecules to be released in a directional manner.

[0009] As an optional implementation, the thermosensitive protective layer includes at least one of the following: a material composed of alginate and divalent metal ion crosslinking system, modified starch and nanocellulose composite system, and chitosan and glycerol composite system.

[0010] As an optional implementation, the thermosensitive protective layer comprises a material composed of an alginate and a divalent metal ion crosslinking system; The fiber substrate layer includes at least one of tobacco fiber base paper and wood fiber base paper, and the basis weight of the fiber substrate layer is 15~100 g / m³. 2 .

[0011] Specifically, in this embodiment of the invention, when the quantitative amount of the fiber substrate layer is less than 15 g / m 2 When the substrate strength is insufficient, on the one hand, the hydrogen bonds between fibers in the substrate break down rapidly when exposed to water during the coating process, making it prone to breakage; on the other hand, the reconstituted tobacco product will also experience abnormal breakage during the winding process due to its low strength and insufficient processing resistance, severely restricting the continuity of production operations, making it difficult to control product quality stably, and increasing material losses. When the basis weight of the fiber substrate layer exceeds 100 g / m², 2 At that time, the reduced flexibility of reconstituted tobacco leaves after coating led to difficulties in winding, and the excessively high fibrous content in the finished reconstituted tobacco leaves resulted in a significant decline in sensory quality. Therefore, the basis weight was limited to 15~100g / m³. 2 Within this range, it can ensure production stability and coating uniformity while taking into account heating aroma release efficiency and sensory quality of reconstituted tobacco products.

[0012] As an optional implementation, the divalent metal ion includes Ca. 2+ Zn 2+ One or a combination of two of them.

[0013] Specifically, Ca 2+ It forms a regular "egg-box" structure in alginate, providing a dense physical fragrance-locking network at room temperature, and undergoes thermal decomposition at 240~300℃ to achieve directional fragrance release; Zn 2+ They participate in crosslinking with different coordination configurations, synergistically regulating the thermal decomposition behavior and mechanical properties of the protective layer.

[0014] Among them, Ca is selected. 2+ and Zn2+ As a divalent metal ion, it is based on the following considerations: Ca 2+ The ionic radius (100 pm) is well matched with the cavity size of the "egg box" formed by the G unit of alginate, which can form a regular and dense cross-linked network to ensure the physical exclusion and aroma-locking effect at room temperature; at the same time, the thermal decomposition behavior of calcium alginate at 240-300℃ is precisely matched with the working temperature of mainstream heated cigarette equipment, which can realize the directional release of aroma.

[0015] Zn 2+ Participating in crosslinking with Ca in a tetrahedral configuration 2+ The planar square configuration forms spatial complementarity, by adjusting Ca 2 + / Zn 2+ The ratio can fine-tune the thermal decomposition initiation temperature and aroma release rate of the protective layer, thereby achieving controlled and slow release of aroma.

[0016] In contrast, Ba 2+ 、Sr 2+ Although it can form stronger cross-links, there are safety concerns; Cu 2+ Mn 2+ Ni 2+ Transition metal ions possess catalytic oxidation activity; if coated on the surface of flavor modification layers, they pose a risk of deterioration to the flavor and fragrance system. (Pb) 2+ Heavy metal ions are highly toxic and are not suitable for tobacco products.

[0017] Secondly, embodiments of the present invention provide a method for preparing functional heated cigarette reconstituted tobacco leaves, comprising the following steps: A smoke-generating liquid is coated onto the surface of the fiber substrate layer and dried to form a smoke-generating layer. A flavor modification layer liquid is coated on the surface of the smoke-generating layer and dried to form a flavor modification layer. A thermosensitive and transparent protective layer liquid is coated on the surface of the flavor modification layer and dried to form a thermosensitive and transparent protective layer. The thermosensitive protective layer is designed to prevent aroma loss and moisture intrusion at room temperature, and to thermally decompose to form a porous structure when heated to 240~300℃ to release aroma.

[0018] As an optional implementation, the thermosensitive protective layer liquid is a mixture of alginate solution and divalent metal ion solution.

[0019] As an optional implementation, the smoke-generating liquid material comprises, by weight, 100 parts of tobacco extract, 14-20 parts of polyol smoke-generating agent, and 0.05-0.2 parts of stabilizer.

[0020] As an optional embodiment, the concentration of the alginate solution is 50-60 g / L, and the concentration of the divalent metal ion solution is 0.1-0.5 mol / L; in the mixed system, the ratio of the alginate solution to the divalent metal ion solution is 1:0.5-2. The G / M unit ratio of the alginate is 1.5 to 2.5.

[0021] It should be noted that when the G / M unit ratio of alginate is less than 1.5, the G unit content is insufficient, the cross-linking points with divalent metal ions decrease, the network structure is loose, and the aroma-locking effect at room temperature decreases; when the G / M ratio is higher than 2.5, the cross-linking is too high, the film density is too large, the thermal decomposition initiation temperature increases when heated, and the aroma release is delayed.

[0022] When the concentration of divalent metal ions is below 0.1 mol / L, the cross-linking reaction is insufficient and there are many defects in the network structure; when it is above 0.5 mol / L, the excess ions cause the cross-linking network to be too rigid, and it is easy to produce explosive release when heated and decomposed.

[0023] When the volume ratio of alginate solution to divalent metal ion solution is less than 1:0.5, the crosslinking agent is insufficient, resulting in inadequate density of the protective layer; when it is greater than 1:2, excessive ion residue will affect sensory quality. As an optional implementation, the dry film coating weight of the thermosensitive protective layer after drying is 4~8 g / m². 2 The coating amount of the smoke-generating layer is 30~55 g / m². 2 The coating amount of the flavor modification layer is 1~4 g / m². 2 .

[0024] Specifically, when the dry film coating amount of the temperature-induced permeability protective layer is less than 4 g / m² 2 At times, if the protective layer is too thin, its physical barrier ability against aroma molecules at room temperature is insufficient; above 8 g / m 2 At this time, an excessively thick protective layer during heating will hinder aroma release and increase costs. When the smoke layer coating amount is less than 30 g / m², 2 At times, if the tobacco extract and smoke-generating agent loading is too low, the strength is insufficient, and the amount of smoke produced is inadequate; if it exceeds 55 g / m³, the smoke will be insufficient. 2 At that time, the coating solution penetrated severely, resulting in excessive stickiness and drying load on the surface of the reconstituted tobacco leaves after coating. When the coating amount of the flavor modification layer was less than 1 g / m², the coating was ineffective. 2 At this time, the characteristic aroma is not obvious; above 4 g / m 2 At that time, the aroma is too strong and easily dissipates.

[0025] As an optional implementation, the moisture content of the smoke-generating layer and the flavor-modifying layer after drying is 7-9 wt%, and the moisture content of the thermosensitive protective layer after drying is 5-7 wt%.

[0026] Specifically, when the moisture content of the smoke layer / flavor modification layer is below 7 wt%, the film layer is too brittle and prone to cracking; when it is above 9 wt%, it is prone to moisture absorption and deterioration during storage. When the moisture content of the protective layer is below 5 wt%, the film layer is too brittle, and the aroma-locking effect at room temperature decreases; when it is above 7 wt%, the film layer is not dense enough, and the water vapor generated during high-temperature thermal decomposition will dilute the aroma to some extent.

[0027] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects: 1. Mechanism Innovation: Utilizing physical exclusion effect to achieve non-adsorption-based, purely physical aroma locking. This invention constructs a functional reconstituted tobacco leaf for heated cigarettes by sequentially compounding a smoke-generating layer, a flavor-modifying layer, and a thermosensitive permeable protective layer on the surface of a fiber substrate layer from the inside out. The smoke-generating layer contains tobacco extracts, polyol smoke-generating agents, and stabilizers; the flavor-modifying layer contains a flavoring and fragrance system; and the thermosensitive permeable protective layer is designed to block aroma loss and moisture intrusion at room temperature. When heated to 240-300°C, it thermally decomposes to form a porous structure, releasing aroma. Unlike existing adsorption-based aroma locking technologies, this method utilizes the thermosensitive permeable protective layer at room temperature... The structure in its normal state forms a physical barrier against aroma molecules in the flavor and fragrance system and external moisture in the flavor modification layer, preventing aroma from escaping and inhibiting moisture from penetrating inward. At the same time, when heated to 240~300℃, the protective layer undergoes thermal decomposition, its structure disintegrates and transforms into a porous form, allowing aroma molecules that were originally sealed inside the protective layer to diffuse and release outward through the porous structure formed by thermal decomposition. Thus, it achieves the effect of locking in aroma and preventing moisture at room temperature, and the effect of releasing aroma when heated, achieving the synergistic function of barrier at room temperature and aroma release through heating.

[0028] 2. Functional Synergistic Innovation: A three-layer functional gradient design achieves phased functional synergy of "room temperature aroma locking and heating aroma release," overcoming the limitations of traditional multi-layer coatings with their physical superposition. This invention involves sequentially composited a smoke-generating layer, a flavor-modifying layer, and a thermosensitive protective layer on the surface of the fiber substrate layer from the inside out. The thermosensitive protective layer comprises at least one of the following: a material composed of a cross-linked system of alginate and divalent metal ions, a modified starch and nanocellulose composite system, or a chitosan and glycerol composite system. The principle lies in utilizing these material systems to form a dense structure with barrier capabilities at room temperature, which thermally decomposes and transforms into a porous structure upon heating to 240-300°C to release aroma. This broadens the selection range of thermosensitive protective layer materials and enhances the applicability of the technical solution. Meanwhile, unlike existing technologies that only use multi-layer coating as a physical layering method, the embodiments of this invention deeply couple the three-layer structure with a specific material (alginate-divalent metal ion crosslinking system), so that the functions of the temperature-sensitive permeable protective layer (room temperature aroma locking and heating aroma release) are linked with the functions of the smoke layer and flavor modification layer (aroma supply and aroma imparting). This achieves the purpose of the protective layer "closing" to protect the aroma of the lower layer at room temperature and "opening" to release the aroma when heated, which cannot be achieved by the simple superposition of multi-layer structures in existing technologies.

[0029] 3. Precise Controlled Release Innovation: Through the G / M ratio, metal ion concentration, and Ca... 2+ / Zn 2+ The synergistic regulation of the combination enables the prepared reconstituted tobacco leaves to block aroma loss and moisture intrusion at room temperature, and achieve controllable aroma release within the target temperature range when heated. In this embodiment of the invention, a smoking layer, a flavor modification layer, and a thermosensitive permeability protection layer are sequentially composited from the inside out on the surface of the fiber substrate layer. The thermosensitive permeability protection layer comprises a material composed of alginate and a divalent metal ion crosslinking system, wherein the divalent metal ions include Ca. 2+ Zn 2+ One or two combinations of Ca, the principle of which lies in utilizing Ca 2+ Zn 2+ It forms characteristic "egg-box" crosslinking points with the G units in alginate. By controlling the crosslinking density of the crosslinking network, the protective layer forms a dense structure at room temperature to prevent aroma loss and moisture intrusion. When heated to 240~300℃, the crosslinking network undergoes thermal decomposition and transforms into a porous structure to release aroma. Simultaneously, through Ca... 2+ / Zn 2+ Adjusting the ratio allows for fine-tuning of the thermal decomposition initiation temperature and aroma release rate, enabling controlled and sustained release of aroma. This achieves precise control of the cross-linked network structure and synergistic effects of room temperature aroma locking and moisture prevention with heating aroma release. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the reconstituted tobacco leaf layered structure provided in an embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0032] Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0033] This invention addresses the shortcomings of existing reconstituted tobacco leaves for heated cigarettes in terms of aroma retention, moisture control, and aroma release matching. It provides a method for preparing functional reconstituted tobacco leaves for heated cigarettes. The method utilizes a material with thermotropic structurally controllable transformation properties to construct a protective layer. At room temperature, this layer is in a dense, aroma-locking, and moisture-proof closed state. At the operating temperature of heated cigarettes, it undergoes thermal decomposition to form a porous structure, transforming into a permeable, aroma-releasing open state. Even after partial aroma release, the remaining skeleton still functions as an effective barrier layer, thus achieving a synergistic unity of moisture control and aroma release functions. Specifically, it includes the following: (1) Preparation of fiber substrate layer The fiber substrate layer includes at least one of tobacco fiber base paper and wood fiber base paper, and the basis weight of the fiber substrate layer is 15~100 g / m³. 2 When the basis weight of the fiber substrate layer is less than 15 g / m 2 When the substrate strength is insufficient, the paper is prone to breakage during coating, and the finished product is easily torn during winding, affecting product quality stability and production efficiency; when the basis weight of the fiber substrate layer is higher than 100 g / m 2 At that time, the flexibility of the reconstituted tobacco products decreased after coating, making it difficult to roll. In addition, the excessive fiber caused an overpowering burnt paper smell and woody odor, which affected the sensory quality of the reconstituted tobacco products.

[0034] (2) Preparation of smoke layer A smoke-generating liquid is coated onto the surface of the fiber substrate layer and dried to form a smoke-generating layer. The drying temperature is 80-120℃, and the drying time is 3-5 minutes. The smoke-generating liquid contains 100 parts of a complete tobacco extract (for ease of understanding, in this embodiment of the invention, the complete tobacco raw materials, by weight, include 59 parts of Yunnan HP11-XY tobacco sheets, 15 parts of Yunnan HP11-XY tobacco sheets, 10 parts of Brazilian B10 / C-C99254 tobacco sheets, and 15 parts of Zimbabwean L10A / 99452ZW tobacco sheets, with a tobacco extract solid content of 40-50% and a Baume degree of 24-30°Be), 14-20 parts of a polyol smoke-generating agent (one or two of 1,2-propylene glycol and glycerol), and 0.05-0.2 parts of a stabilizer (one or more of guar gum, sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose, and ethyl cellulose). The coating weight of the smoke-generating layer after drying is 30-55 g / m². 2 The moisture content of the dried smoke layer is 7-9 wt%.

[0035] (3) Preparation of flavor modification layer A flavor-modifying liquid is coated onto the surface of the smoke-generating layer (the flavor-modifying layer can be selected based on the style characteristics of the corresponding heated cigarette product, such as mint, jasmine, or rose flavoring). After drying, a flavor-modifying layer is formed. The drying temperature is 20-30℃, and the drying time is 2-4 minutes. The flavor-modifying layer contains a flavoring and fragrance system. The coating amount of the flavor-modifying layer after drying is 1-4 g / m³. 2 The moisture content of the flavor-modifying layer after drying is 7-9 wt%.

[0036] (4) Preparation of temperature-sensitive permeable protective layer A thermosensitive protective layer liquid is coated onto the surface of the flavor modification layer and dried to form a thermosensitive protective layer. A gradient drying method is used: pre-drying at 43-47℃ for 10-15 min → intermediate drying at 58-62℃ for 3-6 min → high-temperature film formation at 78-82℃ for 4-8 min. The thermosensitive protective layer liquid is a mixture of alginate solution and divalent metal ion solution (in actual coating, the alginate solution is applied first, followed by the divalent metal ion solution; the ratio of the two is based on the wet film coating volume). The concentration of the alginate solution is 50-60 g / L, the G / M unit ratio of the alginate is 1.5-2.5, the concentration of the divalent metal ion solution is 0.1-0.5 mol / L, and the volume ratio of the alginate solution to the divalent metal ion solution is 1:0.5-2. The divalent metal ions include Ca... 2+ Zn 2+ One or a combination of two of the following: the divalent metal ion solution is one or a mixture of two of CaCl2 solution and ZnCl2 solution. The dry film coating weight of the temperature-sensitive permeable protective layer after drying is 4~8 g / m². 2After drying, the moisture content of the temperature-sensitive and transparent protective layer is 5-7 wt%.

[0037] It should be noted that the drying temperature of the smoke-generating layer is 80~120℃, and the moisture content is controlled at 7~9wt%, providing a smooth and stable coating surface for the subsequent flavor modification layer; the flavor modification layer is dried at a low temperature (20~30℃) to maximize the preservation of the fragrance's activity; the temperature-sensitive transparent protective layer is dried using a gradient drying method (43~47℃→58~62℃→78~82℃), which ensures the dense formation of the cross-linked network while avoiding thermal damage to the lower flavor modification layer. The differentiated design of the three-layer drying conditions (high temperature→low temperature→gradient heating) fully considers the thermal sensitivity of each layer of material and is an important part of the overall technical solution of this invention.

[0038] In other embodiments of the present invention, the thermosensitive protective layer may also be selected from modified starch / nanocellulose composite system or chitosan / glycerol system, and there is no limitation herein.

[0039] This invention addresses the problem of adsorption saturation and slow aroma loss during long-term storage caused by adjusting the G / M unit ratio of alginate to 1.5-2.5 and limiting the concentration of divalent metal ions. This results in a physical exclusion effect that locks aroma molecules below the protective layer, achieving non-adsorption-based pure physical aroma locking. This fundamentally solves the problems of adsorption saturation and slow aroma loss during long-term storage associated with traditional aroma locking methods that rely on adsorption-desorption balance.

[0040] When heated to 240~300℃, the thermosensitive protective layer undergoes thermal decomposition. This process is not an instantaneous and complete collapse, but rather a synergistic effect of room temperature barrier and aroma release within a specific temperature range achieved by controlling the collapse mechanism. Specifically, fragrance molecules are rapidly released in the early stages by utilizing the large pores formed by the material's disintegration, and then slowly diffuse in the later stages by relying on the microporous structure retained in the pyrolysis products. Furthermore, the remaining skeleton after the initial release still functions as an effective barrier layer, thus achieving a leap from adsorption-type fragrance locking to physical exclusion-type fragrance locking. By utilizing the free volume exclusion effect of the cross-linked network to form an unsaturated, non-adsorbent, purely physical barrier, the industry problem of continuous loss of aroma components at room temperature is fundamentally solved.

[0041] Simultaneously, by transforming the thermosensitive protective layer from room temperature density to high temperature permeability, the same protective layer exhibits opposite barrier / permeability characteristics at different temperatures. Moreover, its response temperature of 240~300℃ precisely covers the actual operating temperature range of mainstream heated cigarette equipment (such as IQOS, glo, etc.), achieving a synergistic unity of moisture-proof and aroma-releasing functions, and resolving the functional contradiction that has long plagued this field. This thermosensitive permeability mechanism has no special requirements for the type of flavoring in the flavor modification layer, providing great flexibility for product formulation design. All raw materials used are food contact grade or tobacco-grade materials, and do not contain toxic or harmful additives, possessing excellent prospects for industrial application.

[0042] To better demonstrate the significant effects of the embodiments of the present invention, specific test examples will be set up below for verification.

[0043] Example 1: This embodiment of the invention provides a method for preparing functional heated cigarette reconstituted tobacco, comprising the following: (1) Preparation of fiber substrate layer The fiber substrate layer is made of tobacco fiber base paper (prepared on the papermaking reconstituted tobacco leaf production line of Henan Cigarette Industry Tobacco Sheet Co., Ltd.), and the basis weight of the fiber substrate layer is 50 g / m². 2 .

[0044] (2) Preparation of smoke layer A smoke-generating liquid was coated onto the surface of a fiber substrate layer and dried to form a smoke-generating layer. The drying temperature was 100℃, and the drying time was 4 minutes. The smoke-generating liquid contained 100 parts of tobacco extract with a solid content of 43% and a Baume degree of 25.5°Be, 17 parts of glycerol, and 0.1 parts of sodium carboxymethyl cellulose with a viscosity of 1500 cp. The coating weight of the smoke-generating layer after drying was 40 g / m². 2 The moisture content of the dried smoke layer is 8 wt%.

[0045] (3) Preparation of flavor modification layer Menthol was coated onto the surface of the smoke-generating layer and dried to form a flavor-modifying layer. The drying temperature was 25℃, and the drying time was 3 minutes. The coating weight of the flavor-modifying layer after drying was 2.5 g / m². 2 The moisture content of the flavor-modifying layer after drying is 8 wt%.

[0046] (4) Preparation of temperature-sensitive permeable protective layer Sodium alginate solution (55 g / L, G / M = 2.0) was first coated onto the surface of the flavor modification layer, followed by spraying with CaCl2 solution (0.3 mol / L). The volume ratio of sodium alginate solution to CaCl2 solution was 1:0.8. After drying, a thermosensitive protective layer was formed. A gradient drying method was used: pre-drying at 45℃ for 12 min → intermediate drying at 60℃ for 4 min → high-temperature film formation at 80℃ for 6 min. The divalent metal ions were Ca... 2+ The divalent metal ion solution is CaCl2 solution. After drying, the dry film coating weight of the temperature-sensitive permeable protective layer is 6 g / m². 2 After drying, the moisture content of the temperature-sensitive transparent protective layer is 6wt%.

[0047] Example 2: This embodiment of the invention provides a method for preparing functional heated cigarette reconstituted tobacco, comprising the following: (1) Preparation of fiber substrate layer The fiber substrate layer is made of wood fiber base paper (supplied by China Tobacco Mody (Jiangmen) Paper Co., Ltd., with an air permeability of 11000CU), and the basis weight of the fiber substrate layer is 21 g / m³. 2 .

[0048] (2) Preparation of smoke layer A smoke-generating liquid was coated onto the surface of the fiber substrate layer and dried to form a smoke-generating layer. The drying temperature was 80℃, and the drying time was 3 minutes. The smoke-generating liquid contained 100 parts of tobacco extract with a solid content of 40% and a Baume degree of 24.0°Be, 14 parts of 1,2-propylene glycol, and 0.05 parts of sodium carboxymethyl cellulose with a concentration of 1500 cp. The coating weight of the smoke-generating layer after drying was 30 g / m². 2 The moisture content of the dried smoke layer is 7 wt%.

[0049] (3) Preparation of flavor modification layer Menthol was coated onto the surface of the smoke-generating layer and dried to form a flavor-modifying layer. The drying temperature was 20℃, and the drying time was 2 minutes. The coating weight of the flavor-modifying layer after drying was 1 g / m². 2 The moisture content of the flavor-modifying layer after drying is 7 wt%.

[0050] (4) Preparation of temperature-sensitive permeable protective layer Sodium alginate solution (50 g / L, G / M = 1.5) was first coated onto the surface of the flavor modification layer, followed by spraying with CaCl2 solution (0.1 mol / L). The volume ratio of sodium alginate solution to CaCl2 solution was 1:0.5. After drying, a thermosensitive protective layer was formed. A gradient drying method was used: pre-drying at 43℃ for 10 min → intermediate drying at 58℃ for 3 min → high-temperature film formation at 78℃ for 4 min. The divalent metal ion was Zn. 2+The divalent metal ion solution is a ZnCl2 solution. After drying, the dry film coating weight of the temperature-sensitive permeable protective layer is 4 g / m². 2 After drying, the moisture content of the temperature-sensitive transparent protective layer is 5 wt%.

[0051] Example 3: This embodiment of the invention provides a method for preparing functional heated cigarette reconstituted tobacco, comprising the following: (1) Preparation of fiber substrate layer The fiber substrate layer comprises wood fiber base paper (provided by Mudanjiang Hengfeng Paper Industry Co., Ltd., with an air permeability of 13000CU), and the basis weight of the fiber substrate layer is 40g / m³. 2 .

[0052] (2) Preparation of smoke layer A smoke-generating liquid was coated onto the surface of the fiber substrate layer and dried to form a smoke-generating layer. The drying temperature was 120℃, and the drying time was 5 minutes. The smoke-generating liquid contained 50% solids, 20 parts of tobacco extract (30°Be Baumé), 20 parts of glycerol, and 0.2 parts of sodium carboxymethyl cellulose (1500 cp). The coating weight of the smoke-generating layer after drying was 55 g / m². 2 The moisture content of the dried smoke layer is 9 wt%.

[0053] (3) Preparation of flavor modification layer Menthol was coated onto the surface of the smoke-generating layer, and after drying, a flavor-modifying layer was formed. The drying temperature was 30℃, and the drying time was 4 min. The coating weight of the flavor-modifying layer after drying was 4 g / m². 2 The moisture content of the flavor-modifying layer after drying is 9 wt%.

[0054] (4) Preparation of temperature-sensitive permeable protective layer Sodium alginate solution (60 g / L, G / M = 2.5) was first coated onto the surface of the flavor modification layer, followed by spraying with CaCl2 solution (0.5 mol / L). The volume ratio of sodium alginate solution to CaCl2 solution was 1:2. After drying, a thermosensitive protective layer was formed. A gradient drying method was used: pre-drying at 47℃ for 15 min → intermediate drying at 62℃ for 6 min → high-temperature film formation at 82℃ for 8 min. The divalent metal ions were Ca... 2+ The divalent metal ion solution is CaCl2 solution. After drying, the dry film coating weight of the temperature-sensitive permeable protective layer is 8 g / m². 2 After drying, the moisture content of the temperature-sensitive transparent protective layer is 7wt%.

[0055] Comparative Example 1: A method for preparing reconstituted tobacco leaves for heated cigarettes is provided. The difference from Example 1 is that it does not contain a thermosensitive protective layer, while the other steps remain unchanged.

[0056] The reconstituted tobacco leaves prepared in Examples 1-3 (see example for specific structure) Figure 1 The reconstituted tobacco leaves prepared in the example (shown in Table 1) and Comparative Example 1 were accelerated to age for 7 days at 40℃ and 60%RH. Using deuterated menthol as an internal standard, the retention rate and moisture absorption rate of menthol were determined by GC-MS, and sensory quality was evaluated. The test results and sensory quality evaluation results were compared with the reconstituted tobacco leaf sample without thermosensitive protective layer. The results are shown in Table 1 and Table 2.

[0057] Table 1. Results of menthol retention rate and moisture absorption rate of reconstituted tobacco leaf samples.

[0058] The sensory quality evaluation group is composed of professionals with smoking evaluation qualifications in the industry. It uses a 100-point system to score six items: aroma, smoke, strength, irritation, aftertaste, and uniformity. The aroma evaluation results are divided into three levels: I (maximum score 25.0), II (maximum score 20.0), and III (maximum score 15.0). Each item is scored in units of 0.5 points.

[0059] Table 2 Sensory evaluation results of aroma of reconstituted tobacco samples

[0060] As shown in Tables 1 and 2, compared with the reconstituted tobacco sample without a thermosensitive protective layer prepared in Comparative Example 1, the menthol retention rate of the embodiments of the present invention is significantly improved (from 58.3% to over 90%), and the moisture absorption rate is significantly reduced (from 6.4% to 3.2%~3.8%). Meanwhile, the sensory evaluation result of the reconstituted tobacco sample without a thermosensitive protective layer prepared in Comparative Example 1 is at level II, while the sensory evaluation result of the aroma of the reconstituted tobacco sample prepared in the embodiments of the present invention is at level I, exhibiting a fuller, more delicate, and harmonious aroma than the reconstituted tobacco sample of Comparative Example 1 (the reconstituted tobacco sample of Example 3 scored the highest at 22.5 points, an increase of 2.5 points compared to Comparative Example 1). The above comparison indicates that the presence of the thermosensitive protective layer is key to the improved menthol retention rate and reduced moisture absorption rate. The present invention achieves a synergistic effect of aroma locking and moisture prevention combined with heat-release aroma, which is unattainable by existing technologies, through a three-layer functional gradient design.

[0061] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A functional reconstituted tobacco leaf for heated cigarettes, characterized in that, It includes a fiber substrate layer and a smoke-generating layer, a flavor-modifying layer, and a thermosensitive protective layer sequentially laminated to the surface of the fiber substrate layer from the inside out; The smoke-generating layer contains tobacco extract, polyol smoke-generating agent, and stabilizer; The flavor-modifying layer comprises a flavoring and fragrance system; The thermosensitive protective layer is designed to prevent aroma loss and moisture intrusion at room temperature, and to thermally decompose to form a porous structure when heated to 240~300℃ to release aroma.

2. The functional heated cigarette reconstituted tobacco leaf according to claim 1, characterized in that, The thermosensitive protective layer comprises at least one of the following: a material composed of a cross-linked system of alginate and divalent metal ions, a modified starch and nanocellulose composite material, and a chitosan and glycerol composite material.

3. The functional heated cigarette reconstituted tobacco leaf according to claim 2, characterized in that, The thermosensitive protective layer comprises a material composed of alginate and a divalent metal ion crosslinking system; The fiber substrate layer includes at least one of tobacco fiber base paper and wood fiber base paper, and the basis weight of the fiber substrate layer is 15~100 g / m³. 2 .

4. The functional heated cigarette reconstituted tobacco leaf according to claim 3, characterized in that, The divalent metal ions include Ca. 2+ Zn 2+ One or a combination of two of them.

5. A method for preparing functional heated cigarette reconstituted tobacco as described in any one of claims 1 to 4, characterized in that, Includes the following steps: A smoke-generating liquid is coated onto the surface of the fiber substrate layer and dried to form a smoke-generating layer. A flavor modification layer liquid is coated on the surface of the smoke-generating layer and dried to form a flavor modification layer. A thermosensitive and transparent protective layer liquid is coated on the surface of the flavor modification layer and dried to form a thermosensitive and transparent protective layer. The thermosensitive protective layer is designed to prevent aroma loss and moisture intrusion at room temperature, and to thermally decompose to form a porous structure when heated to 240~300℃ to release aroma.

6. The method for preparing functional heated cigarette reconstituted tobacco according to claim 5, characterized in that, The temperature-sensitive transparent protective layer liquid is a mixture of alginate solution and divalent metal ion solution.

7. The method for preparing functional heated cigarette reconstituted tobacco according to claim 6, characterized in that, By weight, the smoke-generating liquid contains 100 parts of tobacco extract, 14-20 parts of polyol smoke-generating agent, and 0.05-0.2 parts of stabilizer.

8. The method for preparing functional heated cigarette reconstituted tobacco leaves according to claim 6, characterized in that, The concentration of the alginate solution is 50-60 g / L, and the concentration of the divalent metal ion solution is 0.1-0.5 mol / L; in the mixed system, the volume ratio of the alginate solution to the divalent metal ion solution is 1:0.5-2. The G / M unit ratio of the alginate is 1.5 to 2.

5.

9. The method for preparing functional heated cigarette reconstituted tobacco according to claim 5, characterized in that, After drying, the dry film coating weight of the thermosensitive protective layer is 4~8 g / m². 2 The coating amount of the smoke-generating layer is 30~55 g / m². 2 The coating amount of the flavor modification layer is 1~4 g / m². 2 .

10. The method for preparing functional heated cigarette reconstituted tobacco according to claim 9, characterized in that, After drying, the moisture content of the smoke-generating layer and the flavor-modifying layer is 7-9 wt%, and the moisture content of the thermosensitive protective layer is 5-7 wt%.

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