Method for simultaneously reducing polycyclic aromatic hydrocarbon in tobacco leaves and smoke, application and cigarette

Abstract

The invention discloses a method for simultaneously reducing polycyclic aromatic hydrocarbon in tobacco leaves and smoke, application and cigarettes, and relates to the technical field of tobacco processing harm reduction. The method comprises the following steps: preparing a lipase solution; uniformly spraying the lipase solution on the front and back surfaces of the to-be-treated tobacco leaves; the tobacco leaves sprayed with the lipase solution are subjected to constant-temperature and constant-humidity treatment, and the polycyclic aromatic hydrocarbon content of the tobacco leaves subjected to lipase treatment is reduced; shredding the tobacco leaves treated by the lipase, and inactivating the tobacco shreds treated by the lipase by the lipase; the inactivated tobacco shreds are rolled into cigarettes, and the content of polycyclic aromatic hydrocarbon in smoke after the cigarettes are burnt is reduced. The method is suitable for low-grade flue-cured tobacco or threshed and redried tobacco lamina. The cigarette comprises tobacco shreds obtained through lipase treatment. The method is simple and easy to operate, the content of PAHs, especially the content of fluoranthene, in tobacco leaves and smoke can be pertinently reduced after treatment of the lipase preparation, and the safety of the tobacco with the high content of fluoranthene can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of tobacco processing harm reduction, and in particular to a method and application for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke, and cigarettes. Background Art

[0002] Polycyclic aromatic hydrocarbons (PAHs) are aromatic compounds containing at least two benzene rings. They have attracted much attention due to their "three-hazard" effects. The incomplete combustion of carbon-containing fuels such as wood and coal and petroleum refining are important PAHs release processes. The released PAHs can enter the soil directly or indirectly through atmospheric deposition, sewage irrigation, etc., and the soil is its main reservoir. Tobacco is widely grown in more than 100 countries, and PAHs in the soil can be directly or indirectly absorbed and accumulated by tobacco plants. From fresh tobacco leaves to cigarette products, multiple processing steps are required, and the safety of tobacco leaves directly affects the safety of tobacco products.

[0003] Onishi et al. of Japan detected the fluoranthene content in burley tobacco to be 1.4 μg / kg. Ma Jun et al. analyzed the pollution of 16 PAHs in fresh tobacco leaves at maturity in 6 tobacco areas in Songtao County, Guizhou Province and found that the total amount of 16 PAHs in tobacco leaf samples was 502.79 μg / kg~2217.15 μg / kg, with an average value of 1011.23 μg / kg. The average contents of benzo[a]pyrene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[a]anthracene were 404.07 μg / kg, 47.34 μg / kg, 103.05 μg / kg, 78.64 μg / kg, and 23.83 μg / kg, respectively. In addition to the properties of PAHs themselves, the factors that affect the pollution level and distribution of PAHs also depend on the characteristics of the soil itself, the type of plants, and the planting location. CN 109222202 A discloses a method for preparing low-polycyclic aromatic hydrocarbon tobacco flakes by biological method, wherein Bacillus thuringiensis is used in the process of extracting tobacco products, fermenting extracts and fermenting tobacco flake raw materials in the process of preparing tobacco flakes, so as to reduce the content of naphthalene, fluorene and phenanthrene in the smoke of tobacco flakes. CN 109222202 A is only for tobacco flake products, and is added in multiple process flows, which is relatively cumbersome. In other studies, there are few methods for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method which is simple and easy to operate, applicable to most tobacco products, and capable of simultaneously reducing the content of PAHs in tobacco leaves and smoke, thereby improving the safety of tobacco products.

[0005] To this end, the first aspect of the present invention provides a method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke, comprising: preparing lipase solution; The lipase solution is evenly sprayed on the front and back sides of the tobacco leaves to be treated; The tobacco leaves sprayed with the lipase solution are subjected to a constant temperature and humidity treatment to obtain lipase-treated tobacco leaves, wherein the content of polycyclic aromatic hydrocarbons in the lipase-treated tobacco leaves is reduced; Cutting the tobacco leaves treated with lipase into shreds to obtain lipase-treated shredded tobacco; Deactivating the lipase on the shredded tobacco treated with lipase to obtain inactivated shredded tobacco; The inactivated shredded tobacco is rolled into cigarettes, and the content of polycyclic aromatic hydrocarbons in the smoke after the cigarettes are burned is reduced.

[0006] In a feasible implementation manner, the volume concentration of the lipase solution, the lipase stock solution is 3‰-8‰, and the enzyme activity of the lipase stock solution is not less than 6000U / mL.

[0007] In a feasible implementation manner, the volume concentration of the lipase solution or lipase stock solution is 5‰.

[0008] In a feasible embodiment, the step of uniformly spraying the lipase solution on both sides of the tobacco leaves to be treated includes: the ratio of the amount of the lipase solution to the mass of the tobacco leaves to be treated is 0.05%-0.25%.

[0009] In a feasible implementation, the step of uniformly spraying the lipase solution on both sides of the tobacco leaves to be treated includes: the proportion of the lipase solution used in the amount of the tobacco leaves is 0.15% by weight.

[0010] In a feasible implementation manner, the constant temperature and humidity treatment has a temperature of 45±2°C, a humidity of 70%-80%, and a treatment time of 45h-50h.

[0011] In a feasible embodiment, the lipase is inactivated at a temperature of 125±2° C. and stir-fried for 10s-15s.

[0012] After lipase treatment, the fluoranthene content in the tobacco leaves treated with lipase is reduced by more than 90%, and the total amount of five polycyclic aromatic hydrocarbons, including anthracene, fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene, in the tobacco leaves treated with lipase is reduced by more than 30%; the fluoranthene content in the smoke after the cigarette is burned is reduced by more than 35%, and the total amount of five PAHs, including anthracene, fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene, in the smoke after the cigarette is burned is reduced by more than 15%.

[0013] The second aspect of the present invention provides an application of the above-mentioned method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke. The method is applicable to low-grade flue-cured tobacco, and is used to reduce polycyclic aromatic hydrocarbons in low-grade flue-cured tobacco and smoke. It is particularly applicable to tobacco leaves after leaf threshing and re-roasting, and is used to reduce polycyclic aromatic hydrocarbons in tobacco leaves and smoke after leaf threshing and re-roasting.

[0014] A third aspect of the present invention provides a cigarette comprising shredded tobacco and cigarette paper; wherein the shredded tobacco comprises the inactivated shredded tobacco obtained by the above-mentioned method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: The method for reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke provided by the present invention is simple and easy to operate. After being treated with a lipase preparation, substances in tobacco leaves are changed, affecting the combustion characteristics of tobacco leaves and the composition and content of PAHs in smoke. The content of PAHs in tobacco leaves and smoke, especially the content of fluoranthene, can be reduced in a targeted manner, and the safety of tobacco with a high fluoranthene content can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the result chart of the addition ratio for the best sensory evaluation effect after different enzyme dilutions.

[0017] Figure 2 This is a heat map of the changes in the contents of five PAHs in tobacco leaves after different enzyme treatments.

[0018] Figure 3 This is a heat map of the changes in the contents of five PAHs in flue gas after treatment with different enzymes.

[0019] Figure 4 Box plot of the total amount of five PAHs in tobacco leaves after different enzyme treatments.

[0020] Figure 5 Box plot of the total amount of five PAHs in flue gas after treatment with different enzymes. DETAILED DESCRIPTION

[0021] In order to better understand the above technical solution, the technical solution of the present invention is described in detail below through specific embodiments.

[0022] A first aspect of an embodiment of the present invention provides a method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke, comprising: (1) preparing lipase solution; (2) Spraying the lipase solution evenly on both sides of the tobacco leaves to be treated; (3) subjecting the tobacco leaves sprayed with the lipase solution to a constant temperature and humidity treatment to obtain lipase-treated tobacco leaves, wherein the content of polycyclic aromatic hydrocarbons in the lipase-treated tobacco leaves is reduced; (4) shredding the tobacco leaves treated with lipase to obtain shredded tobacco treated with lipase; (5) inactivating the lipase in the shredded tobacco treated with lipase to obtain inactivated shredded tobacco; (6) When the inactivated tobacco is rolled into cigarette sticks, the content of polycyclic aromatic hydrocarbons in the smoke is reduced after combustion.

[0023] It is understandable that PAHs have the characteristics of lipophilicity and hydrophobicity. They are stable, highly toxic and difficult to degrade. They are widely present in tobacco and smoke, which is harmful to human health. Differences in tobacco plant varieties and planting locations will lead to differences in the content of PAHs in tobacco plants.

[0024] The embodiment of the present invention provides a method for reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke at the same time. After being treated with a lipase preparation, the substances in the tobacco leaves change, affecting the combustion characteristics of the tobacco leaves and the composition and content of PAHs in the smoke. It is a highly targeted enzyme preparation harm reduction method, which is simple and easy to operate, can reduce the content of PAHs in tobacco leaves and smoke, especially the fluoranthene content, and can significantly improve the safety of tobacco with high fluoranthene content, and has good application prospects in the field of tobacco harm reduction.

[0025] In some embodiments, the lipase solution is prepared by diluting the lipase stock solution with distilled water, the volume concentration of the lipase stock solution is 3‰-8‰, and the enzyme activity of the lipase stock solution is not less than 6000U / mL; more preferably, the volume concentration of the lipase stock solution is 5‰, and the enzyme activity of the lipase stock solution is not less than 6000U / mL.

[0026] In some embodiments, the lipase solution is evenly sprayed on both sides of the tobacco leaves to be treated, and the amount of the lipase solution is controlled to be 0.05%-0.25% of the mass of the tobacco leaves to be treated; preferably, the amount of the lipase solution is 0.15% of the mass of the tobacco leaves to be treated.

[0027] Specifically, in order to ensure the sensory evaluation effect of tobacco leaves after lipase treatment, the experiment investigated the addition ratio of different lipases (0.05%-0.25%), and it was found that when the proportion of lipase solution to the mass of the tobacco leaves to be treated was 0.15%, it had the best sensory evaluation effect.

[0028] In some embodiments, the constant temperature and humidity treatment is performed at a temperature of 45±2°C, a humidity of 70%-80%, and a time of 45h-50h. Preferably, the temperature is 45°C, the humidity is 75%, and the time is 48h.

[0029] Specifically, the tobacco leaves sprayed with the lipase solution are placed in a constant temperature and humidity chamber, the temperature is controlled at 45±2°C, the humidity is 70%-80%, and the reaction time is 45h-50h, so that the lipase can fully act on the tobacco leaves.

[0030] In some embodiments, the lipase is inactivated at a temperature of 125±2° C. and stir-fried for 10s-15s.

[0031] In some embodiments, the inactivated tobacco is rolled into cigarettes, and the weight of the cigarettes is between 0.850g and 0.900g, preferably 0.875g.

[0032] In summary, after lipase treatment, the fluoranthene content in the tobacco leaves treated with lipase was reduced by more than 90%, and the total amount of five PAHs, including anthracene, fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene, in the tobacco leaves treated with lipase was reduced by more than 30%; when the inactivated tobacco was rolled into cigarettes, the fluoranthene content in the smoke after the cigarettes were burned was reduced by more than 35%, and the total amount of five PAHs, including anthracene, fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene, in the smoke after the cigarettes were burned was reduced by more than 15%.

[0033] A second aspect of an embodiment of the present invention provides an application of the above-mentioned method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke. The method is applicable to low-grade flue-cured tobacco, and is used to reduce polycyclic aromatic hydrocarbons in the smoke of low-grade flue-cured tobacco and low-grade flue-cured tobacco sticks after burning, especially for reducing the content of fluoranthene in the smoke of low-grade flue-cured tobacco and low-grade flue-cured tobacco sticks after burning; it is particularly applicable to leaf-threshed and re-roasted tobacco strips, and is used to reduce polycyclic aromatic hydrocarbons in the smoke of leaf-threshed and re-roasted tobacco strips and tobacco sticks after burning, especially for reducing the content of fluoranthene in the smoke of leaf-threshed and re-roasted tobacco strips and tobacco sticks after burning.

[0034] According to a third aspect of the embodiments of the present invention, a cigarette is provided, comprising shredded tobacco and cigarette paper; wherein the shredded tobacco comprises inactivated shredded tobacco obtained by the above-mentioned method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke.

[0035] The method for collecting the flue gas used in the following embodiments and comparative examples is: After balancing for 48 hours in an environment with a relative humidity of 60±2% and a temperature of 22±1°C, 20 cigarettes (each) and Cambridge filters that meet the weight and draw resistance requirements were smoked using a rotary smoking machine according to the national standard GB / T19609-2004. The smoking parameters were those in ISO mode: 35 mL of puff volume, 2 s of duration, 60 s of puff interval, and a 92 mm Cambridge filter was used to capture the mainstream smoke particles of the 20 cigarettes.

[0036] The determination method of PAHs used in the following examples and comparative examples is: Take tobacco leaf or smoke filter sample, add n-hexane, and ultrasonically extract for 30 minutes. After centrifugation (2280 g, 15 minutes), aspirate the n-hexane layer, add 10mL n-hexane and repeat the extraction once. Mix the two extraction n-hexanes, add to the rotary evaporator and evaporate to dryness. Add 5mL n-hexane to dissolve. Activate the Florisil solid phase extraction column with 5mL dichloromethane and 10mL n-hexane in turn. Transfer all the extract solution dissolved in 5mL n-hexane into the Florisil solid phase extraction column, wash the rotary evaporator with 5mL n-hexane, and merge the washing solution into the column. Elute with 8mL n-hexane-dichloromethane mixed solvent (1:1), collect all the effluent in a 20mL glass centrifuge tube, and blow dry with nitrogen. Make up to 1mL with acetonitrile, mix well, and pass through a 0.22μm organic phase microporous filter membrane to prepare the test solution. Take the test solution into the sampling bottle and determine the content of anthracene, fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene.

[0037] PAHs in tobacco leaf samples were detected and analyzed by liquid chromatography Agilent 1260 Infinity-FLD. A Waters PAH C18 column (4.6mm×250mm, 5µm) was used. Mobile phase A was water and mobile phase B was acetonitrile. The elution gradient was: 0-9min, 60% B; 9-12min, 60%-100% B; 12-28min, 100% B; 28-32min, 100%-60% B; 32-35min, 60% B. The column temperature was 35°C and the flow rate was 1.2mL / min. The injection volume was 10µL. 0.0-12.5min, excitation wavelength 279nm, emission wavelength 340nm; 12.5-13.65min, excitation wavelength 248nm, emission wavelength 375nm; 13.65-15.50min, excitation wavelength 280nm, emission wavelength 462nm; 15.50-17.50min, excitation wavelength 270nm, emission wavelength 385nm; 17.50-18.50min, excitation wavelength 270nm, emission wavelength 446nm; 18.50-25.70min, excitation wavelength 292nm, emission wavelength 410nm; 25.70-35.00min, excitation wavelength 305nm, emission wavelength 480nm.

[0038] Example 1 Determining the addition ratio of lipase-treated tobacco leaves by using sensory evaluation and the content of polycyclic aromatic hydrocarbons in tobacco leaves and smoke after treatment with lipase at the optimal sensory addition ratio 1. Treatment methods The method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke by lipase treatment comprises the following steps: (1) Preparation of lipase solution: Use distilled water to prepare a lipase solution with a volume concentration of 0.5‰ from the lipase stock solution. The nominal activity value of the lipase stock solution is 6000U / mL; (2) Tobacco leaf spraying: Select Chongqing B4F tobacco leaves from 2020, and use an electronic sprayer to evenly spray the prepared lipase solution on the front and back of the tobacco leaves. Set five enzyme addition gradients (the amount of lipase solution as a percentage of tobacco leaf mass), which are 0.1000%, 0.1500%, 0.2000%, 0.2500% and 0.3000% respectively; (3) Tobacco leaf treatment: The tobacco leaves sprayed with lipase were placed in a constant temperature and humidity chamber at 45°C and 75% humidity for 48 hours; (4) Cutting tobacco leaves into shreds: After the tobacco leaves have completed the treatment reaction, use a laboratory small shredder to cut the lipase-treated tobacco leaves into shredded tobacco; (5) Lipase inactivation: Stir-fry the tobacco at 125°C for 15 seconds to inactivate the enzyme in preparation for production; (6) Hand-rolled cigarettes: Use a hand-rolled cigarette rolling machine to roll the inactivated tobacco into a cigarette weighing 0.875g.

[0039] Preparation of control cigarettes: The prepared lipase solution with a volume concentration of 0.5‰ was subjected to a water bath heating inactivation treatment at 100°C for 8 minutes, and then the same tobacco leaf spraying, tobacco leaf treatment, tobacco leaf shredding and hand-rolling as the lipase-treated cigarettes were performed.

[0040] (II) Testing After the cigarettes that meet the weight and draw resistance requirements are placed in an environment with a relative humidity of 60±2% and a temperature of 22±1℃ for 48 hours, they are subjected to two rounds of sensory evaluation by professional smokers, with seven professional smokers in each round. A comprehensive evaluation is conducted on the aftertaste, irritation, concentration, aroma, and other indicators to select the amount of lipase that can significantly improve the quality. Sensory evaluation is the basis for ensuring the quality of tobacco leaves. Figure 1 It can be seen that the best sensory addition ratio of lipase to lipase-treated tobacco leaves is 0.1500% (the proportion of lipase solution used to the mass of tobacco leaves).

[0041] Select cigarettes with lipase added at a ratio of 0.1500%, use a smoking machine to collect the mainstream smoke particles of 20 cigarettes. Determine the contents of five PAHs in tobacco leaves and smoke after combustion: anthracene, fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[a]pyrene. The results of the content and total amount of PAHs in tobacco leaves are as follows: Figure 2 , Figure 4 The results of PAHs content and total amount in flue gas are as follows: Figure 3 , Figure 5After lipase treatment, the fluoranthene content in tobacco leaves decreased by 94.90%, and the total amount of five PAHs decreased by 34.51%; the fluoranthene content in flue gas decreased by 38.82%, and the total amount of five PAHs decreased by 16.33%.

[0042] Comparative Example 1 Determining the addition ratio of pectinase-treated tobacco leaves by using sensory evaluation and the content of polycyclic aromatic hydrocarbons in tobacco leaves and smoke after treatment with the optimal sensory addition ratio of pectinase 1. Treatment methods The method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke by pectinase treatment comprises the following steps: (1) Preparation of enzyme solution: Use distilled water to prepare pectinase solution with a volume concentration of 0.5‰. The nominal activity value of the pectinase stock solution is 6000U / mL. (2) Tobacco leaf spraying: The pectinase solution was evenly sprayed on both sides of the tobacco leaves (2020 Chongqing B4F tobacco leaves), and 5 enzyme addition gradients (the amount of pectinase solution as a percentage of tobacco leaf mass) were set, which were 0.1000%, 0.1500%, 0.2000%, 0.2500% and 0.3000% respectively; (3) Tobacco leaf treatment: The tobacco leaves sprayed with pectinase were placed in a constant temperature and humidity chamber at 45°C and 75% humidity for 48 hours; (4) Cutting tobacco leaves into shreds; cutting the treated tobacco leaves into shreds; (5) Inactivation of pectinase: Stir-fry the tobacco at 125°C for 15 seconds to inactivate the enzyme for production; (6) Hand-rolled cigarettes: Use a hand-rolled cigarette rolling machine to roll the inactivated tobacco into a cigarette weighing 0.875g.

[0043] Preparation of control sample cigarettes: The prepared pectinase solution with a volume concentration of 0.5‰ was subjected to a water bath heating inactivation treatment at 100°C for 8 minutes, and then the same tobacco leaf spraying, tobacco leaf treatment, tobacco leaf shredding and hand-rolling as the pectinase-treated cigarettes were performed.

[0044] (II) Testing After the cigarettes that meet the weight and draw resistance requirements are placed in an environment with a relative humidity of 60±2% and a temperature of 22±1℃ for 48 hours, they are subjected to two rounds of sensory evaluation by professional smokers, with 7 professional smokers in each round. A comprehensive evaluation is conducted on the aftertaste, irritation, concentration, aroma, and other indicators to select the amount of pectinase that can significantly improve the quality. Sensory evaluation is the basis for ensuring the quality of tobacco leaves. Figure 1 It can be seen that the optimal sensory addition ratio of pectinase to tobacco leaves treated with pectinase is 0.2000% (the proportion of pectinase solution used to the mass of tobacco leaves).

[0045] Cigarettes with a pectinase addition ratio of 0.2000% were selected and smoked using a smoking machine to capture the mainstream smoke particles of 20 cigarettes. The contents of five PAHs, anthracene, fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[a]pyrene, in tobacco leaves and smoke after combustion were determined. The results of the content and total amount of PAHs in tobacco leaves are shown in Figure 2. Figure 2 , Figure 4 The results of PAHs content and total amount in flue gas are as follows: Figure 3 , Figure 5 After pectinase treatment, the fluoranthene content in tobacco leaves decreased, the total amount of PAHs in tobacco leaves decreased, the fluoranthene content in smoke did not change significantly, and the total amount of PAHs in smoke increased.

[0046] Comparative Example 2 Determining the addition ratio of amylase-treated tobacco leaves by using sensory evaluation and the content of polycyclic aromatic hydrocarbons in tobacco leaves and smoke after treatment with the optimal sensory addition ratio of amylase 1. Treatment methods The method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke by amylase treatment comprises the following steps: (1) Preparation of enzyme solution: Use distilled water to prepare a 0.5‰ amylase solution, where the nominal activity value of the amylase stock solution is 4500U / mL; (2) Tobacco leaf spraying: The above amylase solutions were evenly sprayed on both sides of tobacco leaves (2020 Chongqing B4F tobacco leaves), and 5 enzyme addition gradients (the amount of amylase solution as a percentage of tobacco leaf mass) were set, which were 0.1000%, 0.1500%, 0.2000%, 0.2500% and 0.3000% respectively; (3) Tobacco leaf treatment: The tobacco leaves sprayed with amylase were placed in a constant temperature and humidity chamber at 45°C and 75% humidity for 48 hours; (4) Cutting tobacco leaves into shreds; cutting the treated tobacco leaves into shreds; (5) Inactivation of amylase: Stir-fry the tobacco at 125°C for 15 seconds to inactivate the enzyme for production; (6) Hand-rolled cigarettes: Use a hand-rolled cigarette rolling machine to roll the inactivated tobacco into a cigarette weighing 0.875g.

[0047] Preparation of control sample cigarettes: The prepared 0.5‰ volume concentration of amylase solution was heated at 100°C for 8 minutes for inactivation, and then the tobacco leaf spraying, tobacco leaf treatment, tobacco leaf shredding and hand-rolling were carried out in the same manner as the amylase-treated cigarettes.

[0048] (II) Testing After the cigarettes that meet the weight and draw resistance requirements are placed in an environment with a relative humidity of 60±2% and a temperature of 22±1℃ for 48 hours, they are subjected to two rounds of sensory evaluation by professional smokers, with 7 professional smokers in each round. A comprehensive evaluation is conducted on the aftertaste, irritation, concentration, aroma, and other indicators to select the amount of amylase that can significantly improve the quality. Sensory evaluation is the basis for ensuring the quality of tobacco leaves. Figure 1 It can be seen that after amylase treatment, the optimal sensory addition ratio of amylase is 0.2500%.

[0049] Cigarettes with 0.2500% amylase addition were selected and smoked using a smoking machine to capture the mainstream smoke particles of 20 cigarettes. The contents of five PAHs, anthracene, fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene, and benzo[a]pyrene, in tobacco leaves and smoke after combustion were determined. The results of the content and total amount of PAHs in tobacco leaves are shown in Figure 2. Figure 2 , Figure 4 The results of PAHs content and total amount in flue gas are as follows: Figure 3 , Figure 5 After amylase treatment, the fluoranthene content in tobacco leaves increased, and the total amount of PAHs in tobacco leaves and smoke increased.

[0050] In summary, tobacco leaves treated with lipase have a good harm reduction effect while meeting the sensory evaluation quality.

[0051] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed. The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application. The above are only preferred implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke, characterized in that: include: preparing lipase solution; The lipase solution is evenly sprayed on the front and back sides of the tobacco leaves to be treated; The tobacco leaves sprayed with the lipase solution are subjected to a constant temperature and humidity treatment to obtain lipase-treated tobacco leaves, wherein the content of polycyclic aromatic hydrocarbons in the lipase-treated tobacco leaves is reduced; Cutting the tobacco leaves treated with lipase into shreds to obtain lipase-treated shredded tobacco; Deactivating the lipase-treated shredded tobacco to obtain inactivated shredded tobacco; The inactivated shredded tobacco is rolled into cigarettes, and the content of polycyclic aromatic hydrocarbons in the smoke after the cigarettes are burned is reduced.

2. The method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke according to claim 1, characterized in that: The volume concentration of the lipase solution and the lipase stock solution is 3‰-8‰, and the enzyme activity of the lipase stock solution is not less than 6000U / mL.

3. The method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke according to claim 2, characterized in that: The volume concentration of the lipase solution and the lipase stock solution is 5‰.

4. The method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke according to claim 1, characterized in that: The step of uniformly spraying the lipase solution on both sides of the tobacco leaves to be treated comprises: the proportion of the lipase solution used to the mass of the tobacco leaves to be treated is 0.05%-0.25%.

5. The method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke according to claim 4, characterized in that: The step of uniformly spraying the lipase solution on both sides of the tobacco leaves to be treated includes: the proportion of the lipase solution used in the tobacco leaves is 0.15% by weight.

6. The method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke according to claim 1, characterized in that: The constant temperature and humidity treatment has a temperature of 45±2° C., a humidity of 70%-80%, and a treatment time of 45h-50h.

7. The method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke according to claim 1, characterized in that: The lipase is inactivated at a temperature of 125±2° C. and stir-fried for 10s-15s.

8. The method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke according to any one of claims 1 to 7, characterized in that: The fluoranthene content in the tobacco leaves treated with the lipase is reduced by more than 90%, and the total amount of five polycyclic aromatic hydrocarbons, namely anthracene, fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene, in the tobacco leaves treated with the lipase is reduced by more than 30%; the fluoranthene content in the smoke after the cigarette is burned is reduced by more than 35%, and the total amount of five PAHs, namely anthracene, fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene, in the smoke after the cigarette is burned is reduced by more than 15%.

9. Application of a method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke, characterized in that: The method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke as described in any one of claims 1 to 8 is used to reduce polycyclic aromatic hydrocarbons in low-grade flue-cured tobacco and smoke, or to reduce polycyclic aromatic hydrocarbons in tobacco leaves and smoke after leaf threshing and re-curing.

10. A cigarette, characterized in that: It comprises shredded tobacco and cigarette paper; wherein the shredded tobacco comprises the inactivated shredded tobacco obtained by the method for simultaneously reducing polycyclic aromatic hydrocarbons in tobacco leaves and smoke as described in any one of claims 1 to 8.

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