A method for improving tobacco leaf quality

Abstract

The present invention discloses a method for improving tobacco leaf quality, and relates to the technical field of tobacco processing. A method for improving tobacco leaf quality of the present invention specifically includes the steps of preparing an enzymatic hydrolysis extract solution, a primary fermentation, and an alcoholization step, wherein composite flavoring particles are added in the step of preparing the enzymatic hydrolysis extract solution, the composite flavoring particles are based on magnetic ferric oxide / porous graphene oxide particles, and the pores of the matrix are filled with modified chitosan, lysine microcapsules are dispersed in the modified chitosan, and the modified chitosan is made of 2,3-epoxypropyltrimethylammonium chloride grafted modified chitosan. The present invention discloses a method for improving tobacco leaf quality, which can improve the smoking quality of tobacco leaves more comprehensively by using tobacco stem enzymatic hydrolysis extract solution and microorganisms, and has a better quality improvement effect.

Description

Technical Field

[0001] The invention relates to the technical field of tobacco processing, and in particular to a method for improving the quality of tobacco leaves. Background Art

[0002] Tobacco is a widely planted cash crop in the world. China is the world's largest tobacco producer and consumer. The economic benefits brought by the tobacco industry are becoming increasingly prominent. Its profits and taxes are also the first in the food industry, becoming an important industry for creating fiscal revenue. With the development of the tobacco industry, people have new requirements for the quality of tobacco. Consumers hope to smoke cigarettes with better smoke, lower toxicity and better taste. In response to this demand, tobacco factories have actively improved tobacco and cigarettes, from the early tobacco planting, grass seed selection and harvesting maturity, to the mid-term processing technology, including primary baking, leaf threshing and re-baking, aging, re-baking, flavoring, to the final cigarette filter rod processing, there are new technologies and new progress, which greatly improve the quality and aroma of cigarettes.

[0003] In the process of tobacco processing, aging is recognized as a key link to improve the quality of tobacco leaves. Tobacco leaf aging is a complex physiological and biochemical process caused by the action of microorganisms in tobacco leaves. This process can not only effectively improve the aroma substances of tobacco leaves, but also reduce the content of substances such as protein, starch, pectin, etc. in tobacco leaves, and improve the taste of cigarettes. Tobacco leaf aging mainly includes natural aging and artificial aging. Natural aging is to store tobacco leaves in a natural environment and ferment them for a long time under natural conditions. The longer the natural aging time, the higher the content of aroma substances in the tobacco leaves. However, too long natural fermentation time is not conducive to tobacco production and increases the cost of tobacco leaves. Artificial fermentation refers to artificially setting temperature and humidity to make tobacco leaves age faster. This method takes a short time, significantly improves the quality of tobacco leaves, and is economical, but the aroma, taste, color, etc. are not as good as naturally aged tobacco leaves.

[0004] With the development of technology, studies have shown that the use of appropriate microorganisms and enzyme preparations can effectively accelerate the aging process of tobacco leaves, thereby improving the quality of tobacco leaves and shortening the aging time. However, due to the different growth habits of various microorganisms and the competition between microorganisms, in actual use, only a single microbial preparation can be used for treatment, and the effect of enhancing the flavor of tobacco leaves is single and incomplete. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to disclose a method for improving the quality of tobacco leaves, which utilizes the combined action of tobacco stem enzymatic hydrolysis extract and microorganisms to more comprehensively improve the smoking quality of tobacco leaves and achieve better quality improvement effects.

[0006] Specifically, a method for improving tobacco leaf quality of the present invention comprises the following steps:

[0007] Preparation of enzymatic hydrolysis extract: Grind the dried tobacco stems to obtain tobacco stem powder, ultrasonically disperse the tobacco stem powder in deionized water, add amylase and pectinase, perform enzymatic hydrolysis once, add protease to perform secondary enzymatic hydrolysis, add composite flavoring particles after the enzymatic hydrolysis is completed, stir to react for 2-3 hours, inactivate the enzyme, continue stirring for 0.5-1 hour, filter, and obtain enzymatic hydrolysis extract;

[0008] Primary fermentation: the tobacco leaves are cured 60 After irradiation with Co-γ rays, the prepared enzymatic extract was sprayed onto the cured tobacco leaves in batches at a mass ratio of 1:50 using a nano-spray nozzle, stirred and mixed evenly, and then stored at 45° C. for 10-12 hours;

[0009] Aging: After the primary fermentation, the tobacco leaves are sprayed with Bacillus cereus microbial agent at a mass ratio of 1:10. After the spraying, the tobacco leaves are packaged and stored in a warehouse for aging.

[0010] The method for improving the quality of tobacco leaves of the present invention utilizes tobacco stems discarded in the tobacco production process as raw materials, performs enzymatic hydrolysis on them, converts macromolecular substances such as starch and cellulose in the tobacco stems into small molecular substances such as glucose, decomposes proteins in the tobacco stems into amino acids, generates Maillard reaction, generates flavor substances, and then adds the amino acids to tobacco leaves, thereby effectively increasing the content of flavor substances in tobacco leaves and improving the smoking quality thereof. The added composite flavoring particles promote the progress of the Maillard reaction and generate more flavor substances, thus achieving a better quality improvement effect on tobacco leaves to a certain extent, and utilizing 60 The gamma rays of Co are radiated to improve the activity of tobacco leaves and their biochemical properties, and then the Bacillus cereus microbial preparation is sprayed, which is conducive to the reaction between Bacillus cereus and macromolecules in the tobacco leaves, promotes the aging of the tobacco leaves, decomposes them into small molecules, and further improves the taste and aroma of the tobacco leaves. The present invention utilizes the tobacco stem enzymatic hydrolysis extract and microorganisms to work together, which can more comprehensively improve the smoking quality of tobacco leaves, and the quality improvement effect is better.

[0011] Furthermore, the composite flavoring particles use magnetic ferroferric oxide / porous graphene oxide particles as a matrix, and the pores of the matrix are filled with modified chitosan, and lysine microcapsules are dispersed in the modified chitosan.

[0012] The present invention adds composite flavoring particles in the step of preparing tobacco stem enzymatic hydrolysis extract. Since the contents of starch and cellulose in tobacco leaves are 4.6% and 42%, respectively, which are much greater than 5% of protein, the occurrence of Maillard reaction is limited. After the composite flavoring particles of the present invention are used, the modified chitosan filled in the pores of the matrix absorbs water and swells, and the lysine microcapsules inside are exposed, and lysine is released into the reaction solution, increasing the content of amino acids, thereby promoting the Maillard reaction and generating more flavor substances. At the same time, during the reaction, the porous graphene oxide as the matrix can also promote the reaction. By dispersing the lysine capsules in the modified chitosan, the lysine is protected on the one hand, and the reaction is prevented. It absorbs carbon dioxide in the air during storage, and on the other hand, protects and limits the microcapsules through modified chitosan to prevent the agglomeration of lysine microcapsules; after the reaction is completed to inactivate the enzyme, the modified chitosan filled in the pores can act as a flocculant to promote the flocculation and agglomeration of the inactivated enzyme. The magnetic ferroferric oxide / porous graphene oxide particles as the matrix have a porous structure with good adsorption performance, which can adsorb the flocculated enzyme and promote its sedimentation. On the other hand, the presence of magnetic ferroferric oxide can facilitate the magnetic separation and recycling of the matrix material. Therefore, through the synergistic effect of the matrix and the filled modified chitosan, the enzyme can be better separated from the enzymatic extraction solution, thereby ensuring the purity of the enzymatic extraction solution.

[0013] Furthermore, the modified chitosan is prepared by grafting 2,3-epoxypropyltrimethylammonium chloride onto modified chitosan.

[0014] Chitosan was grafted with 2,3-epoxypropyltrimethylammonium chloride to increase the cations on the surface of chitosan, improve the flocculation effect of chitosan, and be more conducive to the separation of inactivated enzymes.

[0015] Furthermore, the preparation method of the composite flavoring particles comprises the following steps:

[0016] Preparation of matrix: graphene oxide and polystyrene were stirred and dispersed in deionized water, ultrasonically dispersed for 2 hours, added with liquid nitrogen for instant freezing, vacuum freeze-dried at -70°C for 12 hours, then placed in a tube furnace, heated to 500°C at a rate of 5°C / min under argon atmosphere for constant temperature heat treatment for 2 hours, cooled to room temperature and taken out, stirred and dispersed in deionized water, ammonium ferric sulfate was added, magnetically stirred for 30 minutes, and then 8 mol / L ammonia solution was added dropwise under nitrogen atmosphere, and the reaction was isothermally reacted at 50°C for 1 hour, magnetically separated and dried to obtain the matrix;

[0017] Loading: Sodium β-glycerophosphate is dissolved in deionized water by stirring, and then refrigerated at 4°C for 30 minutes to obtain a 50wt% sodium β-glycerophosphate solution. The modified chitosan is added to a 0.1mol / L hydrochloric acid solution, and stirred continuously until the solution is clarified. The matrix is ​​added and ultrasonically dispersed, and then refrigerated at 4°C for 30 minutes. Lysine microcapsules are added, and sodium carbonate solution is added. Stir continuously until the sodium bicarbonate is completely dissolved. The sodium β-glycerophosphate solution is slowly added. After the addition is completed, stirring is continued for 3-5 hours in an ice water bath. The matrix is ​​fished out, and the temperature is raised to 55-60°C and dried to obtain the composite flavoring particles.

[0018] Sodium carbonate solution is added in the loading step. During the drying process, sodium carbonate is decomposed by heat to generate carbon dioxide, which makes the modified chitosan filled in the pores of the matrix present a porous structure, increases the contact area between the composite flavoring particles and the enzymatic extraction solution, and is more conducive to the swelling of the modified chitosan and the release of lysine.

[0019] Further, the preparation of the modified chitosan: the chitosan powder is dispersed in isopropanol, heated to 80°C with continuous stirring, 2,3-epoxypropyltrimethylammonium chloride solution is added dropwise under constant temperature and continuous stirring, the constant temperature reaction is completed for 7-8 hours, filtered and added into cold acetone, stirred overnight at 4°C to wash the precipitate, filtered and washed three times with cold acetone the next day, and the filter cake is dried at 60°C to obtain the modified chitosan.

[0020] Furthermore, the preparation method of the Bacillus cereus microbial agent is as follows: 0.85% of physiological saline is added to the microbial cells obtained by expanded culture to obtain a 20-30wt% bacterial solution, and then 0.5% of an auxiliary agent is added, and the mixture is incubated at a temperature of 35-37°C for 24 hours to obtain a microbial preparation.

[0021] Furthermore, the Bacillus cereus microbial agent includes Bacillus cereus and an adjuvant, and the mass ratio of the Bacillus cereus to the adjuvant is 1:0.005.

[0022] By adding auxiliary agents, the biological activity of Bacillus cereus can be promoted, so that it can better act on tobacco leaves and improve the quality of tobacco leaves.

[0023] Furthermore, the preparation method of the auxiliary agent is: respectively weigh inorganic salt potassium citrate and sodium dihydrogen phosphate in a ratio of (1.5-2): (3-5), uniformly mix, and prepare a solution with a mass fraction ratio of 0.05-0.1%.

[0024] Beneficial effects of the present invention:

[0025] 1. The present invention discloses a method for improving the quality of tobacco leaves, which utilizes the combined action of tobacco stem enzymatic hydrolysis extract and microorganisms to more comprehensively improve the smoking quality of tobacco leaves, and the quality improvement effect is better.

[0026] 2. A method for improving the quality of tobacco leaves of the present invention can promote the Maillard reaction and the generation of flavor substances by adding composite flavoring particles, thereby being more conducive to flavoring and improving the quality of tobacco leaves. In addition, the use of composite flavoring particles can promote the separation of inactivated enzymes from enzymatic hydrolysis extracts, thereby ensuring the purity of the enzymatic hydrolysis extracts and making them easy to separate and recover. DETAILED DESCRIPTION

[0027] The present invention will be described in detail below with reference to specific embodiments:

[0028] The present invention discloses a method for improving tobacco leaf quality, which utilizes tobacco stem enzymatic hydrolysis extract and microorganisms to improve the smoking quality of tobacco leaves, and adds composite flavoring particles in the step of preparing the enzymatic hydrolysis extract, wherein the composite flavoring particles are based on magnetic ferroferric oxide / porous graphene oxide particles, the pores of the matrix are filled with modified chitosan, and lysine microcapsules are dispersed in the modified chitosan, and the modified chitosan is prepared by grafting 2,3-epoxypropyltrimethylammonium chloride to modified chitosan, specifically as follows:

[0029] Embodiment 1

[0030] Preparation of Lysine Microcapsules

[0031] Weigh zein and stir and dissolve it in 75% ethanol solution to obtain a 10wt% zein-ethanol solution, then add 3% oleic acid and 5% triethyl citrate by weight of the zein-ethanol solution, stir until completely dissolved, degas, and stir in a water bath at 40°C for 4 hours to obtain a capsule wall solution, take 500g L-lysine hydrochloride powder and put it into a fluidized bed, introduce compressed air, set the flow rate of the capsule wall solution to 100ml / min, the fluidized bed temperature to 45°C, and the spray pressure to 0.12MPa for embedding, and after embedding, fluidize and dry at 45°C for 5min to obtain lysine microcapsules.

[0032] Preparation of modified chitosan

[0033] Disperse 50g of chitosan powder in 1L of isopropanol, heat to 80°C with continuous stirring, add 50ml of 20wt% 2,3-epoxypropyltrimethylammonium chloride solution under constant temperature and continuous stirring, and complete the constant temperature reaction for 8h. Filter with suction, add cold acetone and stir overnight at 4°C to wash the precipitate, and filter and wash it three times with cold acetone the next day. Dry the filter cake at 60°C to obtain modified chitosan.

[0034] Preparation of auxiliary agents

[0035] Inorganic salts potassium citrate and sodium dihydrogen phosphate were weighed respectively and uniformly mixed in a mass ratio of 2:5, and deionized water was added to prepare a solution with a mass fraction ratio of 0.08 wt % to obtain an auxiliary agent.

[0036] Preparation method of bacillus cereus microbial agent

[0037] 0.85% physiological saline was added to the microbial cells obtained by the expanded culture to obtain a 30wt% bacterial solution, and then 0.5% of an auxiliary agent was added, and the mixture was incubated at a temperature of 35-37°C for 24 hours to obtain a microbial preparation.

[0038] Preparation of composite flavoring particles:

[0039] Preparation of matrix: 1g of graphene oxide and 1g of polystyrene were weighed and mixed evenly, then dispersed in deionized water with stirring, ultrasonically dispersed for 2h, added with liquid nitrogen for instant freezing, vacuum freeze-dried at -70°C for 12h, then placed in a tube furnace, heated to 500°C at a rate of 5°C / min for constant temperature heat treatment for 2h under argon atmosphere, taken out after cooling to room temperature, dispersed in 400ml of deionized water with stirring, 4g of ammonium ferric sulfate was added, magnetically stirred for 30min, and then 20ml of 8mol / L ammonia solution was added dropwise under nitrogen atmosphere, reacted at 50°C for 1h, magnetically separated and dried to obtain the matrix;

[0040] Loading: Take 5g of sodium β-glycerophosphate and stir to dissolve it in 10ml of deionized water, keep it warm and refrigerate at 4°C for 30min to obtain a 50wt% sodium β-glycerophosphate solution, add 3g of modified chitosan to 100ml of 0.1mol / L hydrochloric acid solution, continue to stir until the solution is clear, add 0.5g to prepare the matrix, keep it warm and refrigerate at 4°C for 30min after ultrasonic dispersion, add 0.1g of lysine microcapsules, add 1ml of sodium carbonate saturated solution, keep stirring and mix evenly, slowly add the sodium β-glycerophosphate solution, after the dropwise addition is completed, keep stirring for 5h under ice-water bath conditions, remove the matrix, heat to 55°C and dry to obtain composite flavoring particles.

[0041] The prepared composite flavoring particles are used to treat tobacco leaves to improve the quality of the tobacco leaves, which specifically includes the following steps:

[0042] Preparation of enzymatic hydrolysis extract: grind 10g of dried tobacco stems to obtain tobacco stem powder, ultrasonically disperse the tobacco stem powder in 120ml of deionized water, add 0.001g of amylase and 0.001g of pectinase, heat to 55°C for primary enzymatic hydrolysis, add 0.001g of protease, perform secondary enzymatic hydrolysis at 55°C for 3h, add 1g of composite flavoring particles after the enzymatic hydrolysis is completed, stir and react for 3h, inactivate the enzyme at 85°C, quickly cool to room temperature, continue stirring for 1h, filter, and obtain an enzymatic hydrolysis extract;

[0043] Primary fermentation: 100g of cured tobacco leaves are treated with 6KGy of 60 After irradiation with Co-γ rays, the prepared enzymatic extract was sprayed onto the cured tobacco leaves in batches using a nano-spray nozzle at a mass ratio of 1:50, stirred and mixed evenly, and then stored at 45°C for 10 hours;

[0044] Aging: After the primary fermentation, the tobacco leaves are sprayed with Bacillus cereus microbial agent at a mass ratio of 1:10. After the spraying, the tobacco leaves are packaged and stored in a warehouse for aging.

[0045] Embodiment 2

[0046] The preparation of lysine microcapsules is the same as that in Example 1.

[0047] Preparation of modified chitosan

[0048] Disperse 40g of chitosan powder in 1L of isopropanol, heat to 80°C with continuous stirring, add 60ml of 20wt% 2,3-epoxypropyltrimethylammonium chloride solution under constant temperature and continuous stirring, and complete the constant temperature reaction for 7h. Filter with suction, add cold acetone and stir overnight at 4°C to wash the precipitate, and filter and wash it three times with cold acetone the next day. Dry the filter cake at 60°C to obtain modified chitosan.

[0049] Preparation of auxiliary agents

[0050] Inorganic salts potassium citrate and sodium dihydrogen phosphate were weighed respectively and uniformly mixed in a ratio of 2:3, and deionized water was added to prepare a solution with a mass fraction ratio of 0.1 wt % to obtain an auxiliary agent.

[0051] Preparation method of bacillus cereus microbial agent

[0052] 0.85% physiological saline was added to the microbial cells obtained by expanded culture to obtain a 20wt% bacterial solution, and then 0.5% auxiliary agent was added, and the mixture was incubated at a temperature of 35-37°C for 24 hours to obtain a microbial preparation.

[0053] Preparation of composite flavoring particles:

[0054] Preparation of matrix: 0.8g of graphene oxide and 0.8g of polystyrene were weighed and mixed, then dispersed in deionized water with stirring, ultrasonically dispersed for 2h, added with liquid nitrogen for instant freezing, vacuum freeze-dried at -70°C for 12h, then placed in a tube furnace, heated to 500°C at a rate of 5°C / min for constant temperature heat treatment for 2h under argon atmosphere, taken out after cooling to room temperature, dispersed in 320ml of deionized water with stirring, 3.2g of ammonium ferric sulfate was added, magnetically stirred for 30min, and then 20ml of 8mol / L ammonia solution was added dropwise under nitrogen atmosphere, and reacted at 50°C for 1h, magnetically separated and dried to obtain the matrix;

[0055] Loading: Take 6g of sodium β-glycerophosphate and stir to dissolve it in 12ml of deionized water, keep it warm and refrigerate at 4°C for 30min to obtain a 50wt% sodium β-glycerophosphate solution, add 2.8g of modified chitosan to 100ml of 0.1mol / L hydrochloric acid solution, continue stirring until the solution is clear, add 0.6g to prepare the matrix, keep it warm and refrigerate at 4°C for 30min after ultrasonic dispersion, add 0.1g of lysine microcapsules, add 1ml of sodium carbonate saturated solution, continue stirring to mix evenly, slowly add the sodium β-glycerophosphate solution, after the dropwise addition is completed, continue stirring for 3h under ice-water bath conditions, remove the matrix, heat to 58°C and dry to obtain composite flavoring particles.

[0056] The prepared composite flavoring particles are used to treat tobacco leaves to improve the quality of the tobacco leaves, which specifically includes the following steps:

[0057] Preparation of enzymatic hydrolysis extract: grind 15g of dried tobacco stems to obtain tobacco stem powder, ultrasonically disperse the tobacco stem powder in 165ml of deionized water, add 0.0015g of amylase and 0.0015g of pectinase, heat to 55°C for primary enzymatic hydrolysis, add 0.0015g of protease, perform secondary enzymatic hydrolysis at 55°C for 3h, add 1g of composite flavoring particles after the enzymatic hydrolysis is completed, stir and react for 3h, inactivate the enzyme at 85°C, quickly cool to room temperature, continue stirring for 0.8h, filter, and obtain an enzymatic hydrolysis extract;

[0058] Primary fermentation: 100g of cured tobacco leaves are treated with 6KGy of 60 After irradiation with Co-γ rays, the prepared enzymatic extract was sprayed onto the cured tobacco leaves in batches using a nano-spray nozzle at a mass ratio of 1:50, stirred and mixed evenly, and then stored at 45°C for 11 hours;

[0059] Aging: After the primary fermentation, the tobacco leaves are sprayed with Bacillus cereus microbial agent at a mass ratio of 1:10. After the spraying, the tobacco leaves are packaged and stored in a warehouse for aging.

[0060] Embodiment 3

[0061] The preparation of lysine microcapsules is the same as that in Example 1.

[0062] Preparation of modified chitosan

[0063] Disperse 30g chitosan powder in 800ml isopropanol, heat to 80℃ with continuous stirring, add 50ml 20wt% 2,3-epoxypropyltrimethylammonium chloride solution under constant temperature and continuous stirring, and complete constant temperature reaction for 8h. Filter with suction, add cold acetone and stir overnight at 4℃ to wash the precipitate, and filter and wash three times with cold acetone the next day. Dry the filter cake at 60℃ to obtain modified chitosan.

[0064] Preparation of auxiliary agents

[0065] Inorganic salts potassium citrate and sodium dihydrogen phosphate were weighed respectively and uniformly mixed in a ratio of 1.5:4, and deionized water was added to prepare a solution with a mass fraction ratio of 0.05 wt % to obtain an auxiliary agent.

[0066] Preparation method of bacillus cereus microbial agent

[0067] 0.85% of physiological saline was added to the microbial cells obtained by the expanded culture to obtain a 25wt% bacterial solution, and then 0.5% of an auxiliary agent was added, and the mixture was incubated at a temperature of 35-37°C for 24 hours to obtain a microbial preparation.

[0068] Preparation of composite flavoring particles:

[0069] Preparation of matrix: 2g of graphene oxide and 2g of polystyrene were weighed and mixed, then dispersed in deionized water with stirring, ultrasonically dispersed for 2h, added with liquid nitrogen for instant freezing, vacuum freeze-dried at -70°C for 12h, then placed in a tube furnace, heated to 500°C at a rate of 5°C / min for constant temperature heat treatment for 2h under argon atmosphere, taken out after cooling to room temperature, dispersed in 800ml of deionized water with stirring, 8g of ammonium ferric sulfate was added, magnetically stirred for 30min, and then 45ml of 8mol / L ammonia solution was added dropwise under nitrogen atmosphere, reacted at 50°C for 1h, magnetically separated and dried to obtain the matrix;

[0070] Loading: Take 4g of sodium β-glycerophosphate and stir to dissolve it in 8ml of deionized water, keep it warm and refrigerate at 4°C for 30min to obtain a 50wt% sodium β-glycerophosphate solution, add 3.5g of modified chitosan to 100ml of 0.1mol / L hydrochloric acid solution, continue to stir until the solution is clear, add 0.4g to prepare the matrix, keep it warm and refrigerate at 4°C for 30min after ultrasonic dispersion, add 0.1g of lysine microcapsules, add 1ml of saturated sodium carbonate solution, keep stirring and mix evenly, slowly add the sodium β-glycerophosphate solution, after the dropwise addition is completed, keep stirring for 4h under ice-water bath conditions, remove the matrix, heat to 60°C and dry to obtain composite flavoring particles.

[0071] The prepared composite flavoring particles are used to treat tobacco leaves to improve the quality of the tobacco leaves, which specifically includes the following steps:

[0072] Preparation of enzymatic hydrolysis extract: 8 g of dried tobacco stems were ground to obtain tobacco stem powder, and the tobacco stem powder was ultrasonically dispersed in 100 ml of deionized water, 0.001 g of amylase and 0.001 g of pectinase were added, and the temperature was raised to 55°C for primary enzymatic hydrolysis, and 0.001 g of protease was added to perform secondary enzymatic hydrolysis at 55°C for 3 h. After the enzymatic hydrolysis was completed, 1 g of composite flavoring particles was added, and the reaction was stirred for 2 h. The enzyme was inactivated at 85°C, and the mixture was rapidly cooled to room temperature. The mixture was continuously stirred for 0.5 h and filtered to obtain an enzymatic hydrolysis extract;

[0073] Primary fermentation: 100g of cured tobacco leaves are treated with 6KGy of 60 After irradiation with Co-γ rays, the prepared enzymatic extract was sprayed onto the cured tobacco leaves in batches using a nano-spray nozzle at a mass ratio of 1:50, stirred and mixed evenly, and then stored at 45°C for 12 hours;

[0074] Aging: After the primary fermentation, the tobacco leaves are sprayed with Bacillus cereus microbial agent at a mass ratio of 1:10. After the spraying, the tobacco leaves are packaged and stored in a warehouse for aging.

[0075] The tobacco leaves prepared in Examples 1 to 3 were aged in a warehouse under the same conditions for 8 months, and samples were taken at the end of the month corresponding to the 8th month. The quality of the tobacco leaves was evaluated and scored using the "nine-point system". At the same time, tobacco leaves without any microbial preparations were used as blank controls, and tobacco leaves with only microbial preparations added were mixed with original tobacco leaves at the same mass ratio of 1:10 as comparative examples. The test results are shown in Table 1:

[0076] Table 1 Evaluation of tobacco leaf quality in one year

[0077] Test items Fragrance Aroma volume Miscellaneous gas concentration Irritant Momentum clean Aftertaste Embodiment 1 8.5 8.5 7.5 8 8 8 7.5 8 Embodiment 2 8 8 8 8 7.5 7.5 8 8 Embodiment 3 8.5 8 7.5 7.5 8 8 7.5 8.5 Comparative Example 7 6.5 6.5 6.5 6 6.5 6 6.5 Blank example 6 5.5 5 5.5 5 5 5 5.5

[0078] It can be clearly seen from the above table that the method of the present invention can significantly improve the quality of tobacco leaves. Compared with the method of only using microbial preparations, the present invention has obvious improvements in various indicators.

[0079] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention. The techniques, shapes, and structural parts not described in detail in the present invention are all known technologies.

Claims

1. A method for improving tobacco leaf quality, characterized in that: The method specifically comprises the following steps: Preparation of enzymatic hydrolysis extract: Grind the dried tobacco stems to obtain tobacco stem powder, ultrasonically disperse the tobacco stem powder in deionized water, add amylase and pectinase, perform enzymatic hydrolysis once, add protease to perform secondary enzymatic hydrolysis, add composite flavoring particles after the enzymatic hydrolysis is completed, stir to react for 2-3 hours, inactivate the enzyme, continue stirring for 0.5-1 hour, filter, and obtain enzymatic hydrolysis extract; Primary fermentation: the cured tobacco leaves are 60 After irradiation with Co-γ rays, the prepared enzymatic extract was sprayed onto the cured tobacco leaves in batches at a mass ratio of 1:50 using a nano-spray nozzle, stirred and mixed evenly, and then stored at 45° C. for 10-12 hours; Aging: Spray the tobacco leaves after primary fermentation with Bacillus cereus microbial agent at a mass ratio of 1:

10. After spraying, pack the tobacco leaves and store them in a warehouse for aging; The composite flavoring particles are based on magnetic ferroferric oxide / porous graphene oxide particles, the pores of the matrix are filled with modified chitosan, and lysine microcapsules are dispersed in the modified chitosan; the modified chitosan is made of 2,3-epoxypropyltrimethylammonium chloride grafted modified chitosan; The preparation method of the composite flavoring particles comprises the following steps: Preparation of matrix: graphene oxide and polystyrene were stirred and dispersed in deionized water, ultrasonically dispersed for 2 hours, added with liquid nitrogen for instant freezing, vacuum freeze-dried at -70°C for 12 hours, then placed in a tube furnace, heated to 500°C at a rate of 5°C / min under argon atmosphere for constant temperature heat treatment for 2 hours, cooled to room temperature and taken out, stirred and dispersed in deionized water, ammonium ferric sulfate was added, magnetically stirred for 30 minutes, and then 8 mol / L ammonia solution was added dropwise under nitrogen atmosphere, and the reaction was isothermally reacted at 50°C for 1 hour, magnetically separated and dried to obtain the matrix; Loading: Sodium β-glycerophosphate is dissolved in deionized water by stirring, and then kept in a refrigerated state at 4°C for 30 minutes to obtain a 50wt% sodium β-glycerophosphate solution. The modified chitosan is added into a 0.1mol / L hydrochloric acid solution, and the solution is stirred continuously until the solution is clarified. The matrix is ​​added and ultrasonically dispersed, and the solution is kept in a refrigerated state at 4°C for 30 minutes. Lysine microcapsules are added, and sodium carbonate solution is added. The sodium bicarbonate is stirred continuously until the sodium bicarbonate is completely dissolved. The sodium β-glycerophosphate solution is slowly added. After the addition is completed, the solution is stirred continuously for 3-5 hours in an ice-water bath. The matrix is ​​fished out, and the temperature is raised to 55-60°C and dried to obtain the composite flavoring particles.

2. A method for improving tobacco leaf quality according to claim 1, characterized in that: Preparation of the modified chitosan: chitosan powder is dispersed in isopropanol, heated to 80°C with continuous stirring, 2,3-epoxypropyltrimethylammonium chloride solution is added dropwise under constant temperature and continuous stirring, the constant temperature reaction is completed for 7-8 hours, filtered and added into cold acetone, stirred overnight at 4°C to wash the precipitate, filtered and washed three times with cold acetone the next day, and the filter cake is dried at 60°C to obtain the modified chitosan.

3. A method for improving tobacco leaf quality according to claim 2, characterized in that: The preparation method of the Bacillus cereus microbial agent is as follows: 0.85% physiological saline is added to the microbial cells obtained by expanded culture to obtain a 20-30wt% bacterial solution, and then 0.5% auxiliary agent is added, and the mixture is incubated at a temperature of 35-37°C for 24 hours to obtain the microbial agent.

4. The method for improving tobacco leaf quality according to claim 3, characterized in that: The Bacillus cereus microbial agent comprises Bacillus cereus and an auxiliary agent, and the mass ratio of the Bacillus cereus to the auxiliary agent is 1:0.

005.

5. The method for improving tobacco leaf quality according to claim 4, characterized in that: The preparation method of the auxiliary agent is: respectively weigh inorganic salt potassium citrate and sodium dihydrogen phosphate and uniformly mix them in a ratio of (1.5-2):(3-5) to prepare a solution with a mass fraction ratio of 0.05-0.1%.