Fermentation method for reducing nitrosamine content in cigar tobacco
The fermentation method using tea polyphenols and pH adjustment to 5-6.5 inhibits nitrosamine formation in cigar tobacco by promoting Bacillus growth, achieving significant nitrosamine reduction without heavy metal residues.
Patent Information
- Application Number
- CN202411574847.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2025-01-03
AI Technical Summary
Existing methods for reducing nitrosamine content in cigar tobacco, such as using sodium tungstate, result in heavy metal residues, and there is a need for an effective method to inhibit nitrosamine formation during fermentation without such drawbacks.
A fermentation method involving the use of a tea polyphenol aqueous solution sprayed on cigar tobacco leaves to inhibit nitrate reductase activity, combined with a pH adjustment to 5-6.5 to promote the growth of Bacillus bacteria, which competes with mold and reduces nitrosamine formation.
The method effectively reduces nitrosamine content in cigar tobacco by up to 52.34% and in finished cigars by 49.23%, avoiding heavy metal residues and improving product quality.
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Figure CN119235050A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of tobacco preparation, and in particular to a fermentation method for reducing the content of nitrosamines in cigar tobacco. Background Art
[0002] Tobacco contains more than 50 alkaloids, among which nicotine, anatabine, anabasine, nornicotine, etc. Nicotine has the highest content, generally accounting for more than 90% of the total alkaloid components, while the proportion of other alkaloids generally does not exceed 10%, and the content of nornicotine is generally lower than 3.5% of the total alkaloid content.
[0003] There are four common nitrosamines unique to tobacco, namely N-nitrosonicotine, 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone, N-nitrosoanatabine and N-nitrosoanatabine. Nicotine, nornicotine, anabasine and anabasine can undergo nitrosation reactions during tobacco leaf preparation and fermentation to form N-nitrosonicotine, 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone, N-nitrosoanatabine and N-nitrosoanatabine, respectively. Among them, 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone and N-nitrosonicotine have been listed as Class I carcinogens.
[0004] However, under different agronomic measures, preparation methods and fermentation conditions, the conversion of nicotine to nornicotine may lead to an increase in nornicotine content, which in turn may increase the content of N-nitrosonornicotine and total nitrosamines. Studies have shown that during the fermentation process of cigar tobacco, the accumulation of nitrosamines exceeds 50% of the total nitrosamine accumulation in the entire tobacco leaf production stage.
[0005] In the prior art, during the tobacco production process, the formation and accumulation of nitrosamines in tobacco leaves are inhibited by spraying a sodium tungstate aqueous solution on the tobacco leaf surface. However, sodium tungstate will cause heavy metal residues during use. Summary of the invention
[0006] In order to solve the above technical problems, the present invention provides a fermentation method for reducing the nitrosamine content in cigar tobacco, so as to reduce the nitrosamine content in cigar tobacco.
[0007] To achieve the above objectives, the specific technical solutions of the present invention are as follows.
[0008] A fermentation method for reducing the nitrosamine content in cigar tobacco comprises the following steps:
[0009] Cigar tobacco leaves are treated with a buffer solution to adjust the pH value to 5-6.5 to obtain pretreated cigar tobacco leaves; a tea polyphenol aqueous solution is sprayed on the pretreated cigar tobacco leaves, and then fermented, and the tea polyphenol is used to inhibit the activity of nitrate reductase produced in the process of microbial decomposition of cigar tobacco leaves, so as to reduce the accumulation of nitrosamines; the concentration of the tea polyphenol aqueous solution is 100μg / mL-400μg / mL; and the spraying amount of the tea polyphenol aqueous solution accounts for 0.001%-0.5% of the dry basis weight of the pretreated cigar tobacco leaves.
[0010] The present invention uses a buffer to ensure that the pH value is between 5.0 and 6.5, so that the tea polyphenol aqueous solution inhibits mold from decomposing nitrate reductase. Since different bacterial genera are adapted to different pH values, the weakly acidic environment is more suitable for the growth of Bacillus, which can effectively decompose the protein in tobacco leaves into amino acids and other small molecules, so that the prepared cigar has a softer taste. Cigar tobacco leaf fermentation itself is to reduce the green impurities, earthy impurities, irritating taste, etc. of tobacco leaves, so the weakly acidic environment is more suitable for cigar tobacco leaf fermentation. There is a competition between Bacillus and mold growth, and they will compete with each other for nutrients and space required for growth. And Bacillus can produce enzymes that inhibit mold growth, so the weakly acidic environment is to help the growth of dominant bacterial genera in cigar tobacco leaves, that is, to help the growth of Bacillus in cigar tobacco leaves and inhibit mold production. In the case of strong acid or strong alkali, cigar tobacco leaves cannot be fermented smoothly. Therefore, during the fermentation of cigar tobacco leaves, the dominant bacterial genera are more conducive to growth in a weakly acidic environment, thereby effectively inhibiting the production of nitrate reductase by mold.
[0011] In addition, during the fermentation process of cigar tobacco leaves, there are many microorganisms with nitrate reduction function on the surface of tobacco leaves, especially molds, and the nitrate reductase decomposed by them can significantly increase the nitrite content of the direct precursor of tobacco-specific nitrosamines, such as proteins and polysaccharides in tobacco leaves, and nitrites further react with alkaloids to form tobacco-specific nitrosamines, resulting in an increase in the tobacco nitrosamine content in the fermented tobacco leaves. The present invention can inhibit the activity of nitrate reductase decomposed by microorganisms, especially molds, during the fermentation process through tea polyphenols, reduce the formation of nitrites by proteins and polysaccharides in tobacco leaves, and further prevent nitrites from further reacting with alkaloids to form tobacco-specific nitrosamines, so as to achieve the purpose of reducing the content of tobacco-specific nitrosamines.
[0012] In a preferred embodiment, the fermentation mixture further comprises:
[0013] The cigar tobacco leaves in the fermentation mixture are tied into bundles of 30 to 35 leaves per bundle, and the bundles are piled into a pile for fermentation.
[0014] In a preferred embodiment, the width of the smoke pile is 2m to 2.5m, the height is 1.5m to 1.8m, and the length is 4m to 4.5m.
[0015] In a preferred embodiment, the specific process of the fermentation is as follows:
[0016] The tobacco pile is turned over every 6 to 7 days, and the tea polyphenol aqueous solution is sprayed after each turning; the spraying amount of the tea polyphenol aqueous solution after each turning accounts for 0.001% to 0.5% of the dry basis weight of the cigar tobacco leaves to be fermented.
[0017] In a preferred embodiment, the fermentation time is 35 to 42 days, and the temperature is 37° C. to 43° C. This temperature is to avoid the inhibitory effect of tea polyphenols on the nitrate reductase decomposing the mold due to excessively high temperature.
[0018] In a preferred embodiment, the buffer is a sodium bicarbonate buffer, and the concentration of the sodium bicarbonate buffer is 0.01 mol / L to 0.5 mol / L.
[0019] In a preferred embodiment, the sodium bicarbonate buffer solution is obtained by mixing Na2CO3 solution and NaHCO3 solution in a volume ratio of 1 to 9:1 to 9; the concentration of the Na2CO3 solution is 0.01 mol / L to 0.5 mol / L; the concentration of the NaHCO3 solution is 0.01 mol / L to 0.5 mol / L.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] (1) The present invention utilizes tea polyphenols to inhibit the activity of nitrate reductase decomposing microorganisms such as molds, thereby reducing the effect of nitrate reductase on substances such as proteins and polysaccharides, thereby reducing the nitrosamines in the fermented cigar tobacco leaves. In addition, the fermentation is carried out in an environment with a pH value of 5 to 6.5, that is, in a weakly acidic environment, which is conducive to the growth of the dominant bacteria genus Bacillus, and Bacillus can inhibit the growth of molds, and further inhibit the molds from producing nitrate reductase. Through the fermentation method of the present invention, the nitrosamine content in the fermented cigar tobacco leaves can be reduced by up to 52.34%, and the rolled cigar finished product can be reduced by 49.23%. Unlike the heavy metal residues and other problems caused by sodium tungstate, tea polyphenols are a food flavoring that not only does not have the problem of heavy metal residues, but also can inhibit the formation of nitrosamines in cigar tobacco leaves, reduce the harm of cigar products to the human body, increase and regulate the flavor of cigar products, and improve the quality of the obtained cigar products.
[0022] (2) When the concentration of tea polyphenols is 400 μg / mL and the spraying amount of the tea polyphenols aqueous solution accounts for 0.05% of the dry basis of tobacco leaves, the nitrosamines in the tobacco leaves can be reduced by 52.34%, and the nitrosamines in the rolled cigar products can be reduced by 49.23%. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is a diagram showing the mechanism of reducing nitrosamines according to the present invention.
[0024] Figure 2 It is a line graph showing that different concentrations of tea polyphenols aqueous solution in the embodiment of the present invention reduce the nitrosamine content in cigar tobacco leaves.
[0025] Figure 3 The figure is a line graph showing that different concentrations of tea polyphenol aqueous solutions in the embodiments of the present invention reduce the nitrosamine content in the finished cigar products. DETAILED DESCRIPTION
[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0027] Unless otherwise specified, the experimental methods described in the following examples are all conventional methods; the reagents and materials described are all commercially available unless otherwise specified.
[0028] Fermentation is an important link in the production process of cigar tobacco leaves, and it can be said to be the main factor affecting the quality of finished cigar tobacco products. After fermentation, the color of tobacco leaves becomes darker, macromolecular substances such as protein and starch are further degraded and transformed, the aroma components increase, the chemical composition is more coordinated, the impurities and irritation are reduced, the adverse sensory effects such as bitterness and tongue lag are reduced, the aftertaste is comfortable, the quality of tobacco leaves is significantly improved, and the industrial availability is improved. However, fermentation is also one of the important periods for the formation of tobacco-specific nitrosamines, which are harmful components in tobacco leaves. Generally speaking, the cells of fresh tobacco leaves are intact, and the selective permeability of various biofilms isolates the substrates that form tobacco-specific nitrosamines from each other, making it difficult for nitrosation reactions to occur. Therefore, the content of tobacco-specific nitrosamines in fresh tobacco leaves is extremely low, or even absent, and the main stages of its formation and accumulation are the modulation, fermentation and storage processes of tobacco leaves.
[0029] The alkaloid content of tobacco leaves continues to increase in the first three weeks of fermentation, and begins to slowly decline from 4 to 5 weeks. After 5 weeks, the alkaloid content is still higher than the unfermented level. However, as fermentation continues, the alkaloid content continues to decrease, and eventually falls below that of unfermented tobacco leaves. There have been studies on the curing process, and the results show that increasing the air-drying time at the beginning of curing reduces the rate of water loss in tobacco leaves, provides conditions for the full degradation of macromolecular substances such as pigments, improves the appearance quality of tobacco leaves, and makes the chemical composition more coordinated. During the yellowing period of air-drying, due to the increased permeability of the cell membrane, the cell membrane is damaged, and the cell contents flow out, which gives the precursors of nitrosamines the opportunity to react with each other. Therefore, the nitrosamine content begins to increase significantly during the yellowing period of air-drying.
[0030] During the drying process, as the permeability of the cell membrane increases, NO2, sugar, water and other microorganisms flow out of the cells, providing the necessary nutrients for the activities of microorganisms. In addition, with the appropriate temperature, humidity and anaerobic conditions, the activity of microorganisms is greatly enhanced, thereby promoting the reaction of nitrate reduction to nitrite, and then inducing the nitrosation reaction of alkaloids to form nitrosamines. In addition, during the fermentation of cigar tobacco leaves, as the temperature rises, the activity of microorganisms is enhanced, which promotes the nitrosation reaction of alkaloids and also causes an increase in the content of nitrosamines. On the other hand, nitrates in tobacco leaves may directly generate gaseous nitrogen oxides at higher temperatures, which in turn promote the nitrosation reaction of alkaloids to form nitrosamines. Studies have shown that the accumulation of tobacco-specific nitrosamines during the fermentation stage of cigar tobacco can reach or even exceed 50% of the total accumulation of tobacco-specific nitrosamines during the entire tobacco production stage. If the synthesis of tobacco-specific nitrosamines at this stage can be inhibited, the content of tobacco-specific nitrosamines in cigar tobacco leaves will be greatly reduced.
[0031] The present invention provides a fermentation method for reducing the nitrosamine content in cigar tobacco, wherein the mechanism of the tea polyphenol aqueous solution inhibiting nitrosamine is shown in Figure 1 Tea polyphenols can inhibit the activity of nitrate reductase decomposed by microorganisms such as molds, reduce the effect of nitrate reductase on substances such as proteins and polysaccharides, and thus reduce the nitrosamines in cigar tobacco leaves after fermentation. Tea polyphenols can inhibit the activity of nitrate reductase decomposed by microorganisms such as molds, reduce the effect of nitrate reductase on substances such as proteins and polysaccharides, and thus reduce the nitrosamines in cigar tobacco leaves after fermentation. In addition, during the entire fermentation process, the present invention is in a weak acid environment with a pH value of 5 to 6.5, which is not only conducive to the growth of Bacillus, but also Bacillus can inhibit the growth of molds, thereby further preventing the molds from producing nitrate reductase.
[0032] A fermentation method for reducing the nitrosamine content in cigar tobacco is specifically described below.
[0033] Example 1
[0034] A fermentation method for reducing the content of tobacco-specific nitrosamines in cigar tobacco comprises the following steps:
[0035] S1. Mixing a 0.01 mol / L Na2CO3 aqueous solution and a 0.01 mol / L NaHCO3 aqueous solution, and adjusting the pH value to 5.5 to obtain a sodium bicarbonate buffer solution; spraying the sodium bicarbonate buffer solution on cigar tobacco leaves to be fermented to adjust the pH value of the cigar tobacco leaves to be fermented to 5.5, to obtain pretreated cigar tobacco leaves; wherein the spraying amount of the sodium bicarbonate buffer solution accounts for 0.1% of the dry basis weight of the cigar tobacco leaves to be fermented.
[0036] S2. Prepare a 100 μg / mL tea polyphenols aqueous solution with purified water, and evenly spray the tea polyphenols aqueous solution on the pretreated cigar tobacco leaves, wherein the spraying amount of the tea polyphenols aqueous solution accounts for 0.001% of the dry basis weight of the pretreated cigar tobacco leaves, to obtain a fermentation mixture.
[0037] S3. The cigar tobacco leaves in the fermentation mixture are tied into bundles of 30 pieces / bundle for fermentation, and the bundles are piled into a pile with a width of 2m, a height of 1.5m and a length of 4m, and fermented for 35 days in a weak acid environment with a pH value of 5.5; during the fermentation process, the pile is turned once every 6 days, and the tea polyphenols aqueous solution is sprayed once each time the pile is turned, and the total amount of the tea polyphenols aqueous solution sprayed each time accounts for 0.05% of the dry basis weight of the cigar tobacco leaves to be fermented, and the temperature of the fermentation and the turning of the pile is controlled at 40°C.
[0038] Example 2
[0039] A fermentation method for reducing the content of tobacco-specific nitrosamines in cigar tobacco comprises the following steps:
[0040] S1. Mixing a 0.01 mol / L Na2CO3 aqueous solution and a 0.01 mol / L NaHCO3 aqueous solution, and adjusting the pH value to 6.34 to obtain a sodium bicarbonate buffer solution; spraying the sodium bicarbonate buffer solution on cigar tobacco leaves to be fermented to adjust the pH value of the cigar tobacco leaves to be fermented to 6.34, to obtain pretreated cigar tobacco leaves; wherein the spraying amount of the sodium bicarbonate buffer solution accounts for 2% of the dry basis weight of the cigar tobacco leaves to be fermented.
[0041] S2. Prepare a 200 μg / mL tea polyphenols aqueous solution with purified water, and spray the tea polyphenols aqueous solution evenly on the pretreated cigar tobacco leaves, wherein the spraying amount of the tea polyphenols aqueous solution accounts for 0.1% of the dry basis weight of the pretreated cigar tobacco leaves, to obtain a fermentation mixture.
[0042] S3. The cigar tobacco leaves in the fermentation mixture are tied into bundles of 33 pieces / bundle and put into a pile for fermentation, and the bundles are piled into a pile with a width of 2.5m, a height of 1.8m and a length of 4.5m, and fermented for 40 days in a weakly acidic environment with a pH value of 6.34; during the fermentation process, the pile is turned once every 6 days, and the tea polyphenols aqueous solution is sprayed once each time the pile is turned; wherein the total amount of tea polyphenols sprayed each time accounts for 0.1% of the dry basis weight of the cigar tobacco leaves to be fermented, and the temperature of the fermentation and the turning of the pile is controlled at 42°C.
[0043] Example 3
[0044] A fermentation method for reducing the content of tobacco-specific nitrosamines in cigar tobacco comprises the following steps:
[0045] S1. Mixing 0.01 mol / L Na2CO3 solution and 0.01 mol / L NaHCO3 solution, and adjusting the pH value to 5.74 to obtain a sodium bicarbonate buffer solution; spraying the sodium bicarbonate buffer solution on cigar tobacco leaves to be fermented to adjust the pH value of the cigar tobacco leaves to be fermented to 5.74, to obtain pretreated cigar tobacco leaves; wherein the spraying amount of the sodium bicarbonate buffer solution accounts for 0.1% of the dry basis weight of the cigar tobacco leaves to be fermented.
[0046] S2. Prepare a tea polyphenol aqueous solution with a concentration of 100 μg / mL, and spray the tea polyphenol spray solution evenly on the pretreated cigar tobacco leaves, wherein the spraying amount of the tea polyphenol aqueous solution accounts for 0.2% of the dry basis weight of the pretreated cigar tobacco leaves to obtain a fermentation mixture.
[0047] S3. The cigar tobacco leaves in the fermentation mixture are tied into bundles of 35 pieces / bundle and put into a pile for fermentation. The bundles are piled into a pile with a width of 2m, a height of 1.5m and a length of 4m, and fermented for 40 days in a weak acid environment with a pH value of 5.74. During the fermentation process, the pile is turned once every 6 days, and the tea polyphenols aqueous solution is sprayed once each time the pile is turned; the total amount of tea polyphenols sprayed accounts for 0.05% by weight of the dry basis of the tobacco leaves, and the temperature of the fermentation and the turning of the pile is controlled at 37°C.
[0048] Example 4
[0049] A fermentation method for reducing the content of tobacco-specific nitrosamines in cigar tobacco comprises the following steps:
[0050] S1. Mixing 0.01 mol / L Na2CO3 solution and 0.01 mol / L NaHCO3 solution, and adjusting the pH value to 5.74 to obtain a sodium bicarbonate buffer solution; spraying the sodium bicarbonate buffer solution on cigar tobacco leaves to be fermented to adjust the pH value of the cigar tobacco leaves to be fermented to 5.74, to obtain pretreated cigar tobacco leaves; wherein the spraying amount of the sodium bicarbonate buffer solution accounts for 0.1% of the dry basis weight of the cigar tobacco leaves to be fermented.
[0051] S2. Prepare a tea polyphenol aqueous solution with a concentration of 200 μg / mL, and spray the tea polyphenol spray solution evenly on the pretreated cigar tobacco leaves, wherein the spraying amount of the tea polyphenol aqueous solution accounts for 0.3% of the pretreated cigar tobacco leaf dry matrix to obtain a fermentation mixture.
[0052] S3. The cigar tobacco leaves in the fermentation mixture are tied into bundles of 30 pieces / bundle and put into a pile for fermentation, and the bundles are piled into a pile with a width of 2m, a height of 1.5m and a length of 4m, and fermented for 40 days in a weak acid environment with a pH value of 5.74; during the fermentation process, the pile is turned once every 6 days, and the tea polyphenol aqueous solution is sprayed once each time the pile is turned; the total amount of tea polyphenols sprayed accounts for 0.05% of the dry basis weight of the cigar tobacco leaves to be fermented, and the temperature of fermentation and turning the pile is controlled at 43°C.
[0053] Example 5
[0054] A fermentation method for reducing the content of tobacco-specific nitrosamines in cigar tobacco comprises the following steps:
[0055] S1. Mixing 0.01 mol / L Na2CO3 solution and 0.01 mol / L NaHCO3 solution, and adjusting the pH value to 5.74 to obtain a sodium bicarbonate buffer solution; spraying the sodium bicarbonate buffer solution on cigar tobacco leaves to be fermented to adjust the pH value of the cigar tobacco leaves to be fermented to 5.74, to obtain pretreated cigar tobacco leaves; wherein the spraying amount of the sodium bicarbonate buffer solution accounts for 0.1% of the dry basis weight of the cigar tobacco leaves to be fermented.
[0056] S2. Prepare a tea polyphenol aqueous solution with a concentration of 300 μg / mL, and spray the tea polyphenol spray solution evenly on the pretreated cigar tobacco leaves, wherein the spraying amount of the tea polyphenol aqueous solution accounts for 0.4% of the dry basis weight of the pretreated cigar tobacco leaves to obtain a fermentation mixture.
[0057] S3. The cigar tobacco leaves in the fermentation mixture are tied into bundles of 30 pieces / bundle and put into a pile for fermentation, and the bundles are piled into a pile with a width of 2m, a height of 1.5m and a length of 4m, and fermented for 40 days in a weak acid environment with a pH value of 5.74; during the fermentation process, the pile is turned once every 6 days, and the tea polyphenols aqueous solution is sprayed once each time the pile is turned; the total amount of the tea polyphenols aqueous solution sprayed each time accounts for 0.05% of the dry basis weight of the cigar tobacco leaves to be fermented, and the temperature of the fermentation and the turning of the pile is controlled at 40°C.
[0058] Example 6
[0059] A fermentation method for reducing the content of tobacco-specific nitrosamines in cigar tobacco comprises the following steps:
[0060] S1. Mixing 0.01 mol / L Na2CO3 solution and 0.01 mol / L NaHCO3 solution, and adjusting the pH value to 5.74 to obtain a sodium bicarbonate buffer solution; spraying the sodium bicarbonate buffer solution on cigar tobacco leaves to be fermented to adjust the pH value of the cigar tobacco leaves to be fermented to 5.74, to obtain pretreated cigar tobacco leaves; wherein the spraying amount of the sodium bicarbonate buffer solution accounts for 0.1% of the dry basis weight of the cigar tobacco leaves to be fermented.
[0061] S2. Prepare a tea polyphenol aqueous solution with a concentration of 400 μg / mL, and spray the tea polyphenol spray solution evenly on the pretreated cigar tobacco leaves, wherein the spraying amount of the tea polyphenol aqueous solution accounts for 0.5% of the dry basis weight of the pretreated cigar tobacco leaves to obtain a fermentation mixture.
[0062] S3. The cigar tobacco leaves in the fermentation mixture are tied into bundles of 30 pieces / bundle and put into a pile for fermentation. The bundles are piled into a pile with a width of 2m, a height of 1.5m and a length of 4m, and fermented for 40 days in a weakly acidic environment with a pH value of 5.74. During the fermentation process, the pile is turned once every 6 days, and the tea polyphenols aqueous solution is sprayed once each time the pile is turned; the total amount of the tea polyphenols aqueous solution sprayed accounts for 0.05% by weight of the dry basis of the tobacco leaves, and the temperature of the fermentation and the turning of the pile is controlled at 40°C.
[0063] Comparative Example 1
[0064] A fermentation method for reducing the nitrosamine content in cigar tobacco comprises the following steps:
[0065] S1. Mixing a 0.01 mol / L Na2CO3 aqueous solution and a 0.01 mol / L NaHCO3 aqueous solution, and adjusting the pH value to 5.74 to obtain a sodium bicarbonate buffer solution; spraying the sodium bicarbonate buffer solution on cigar tobacco leaves to be fermented to adjust the pH value of the cigar tobacco leaves to be fermented to 5.5, to obtain pretreated cigar tobacco leaves; wherein the spraying amount of the sodium bicarbonate buffer solution accounts for 0.1% of the dry basis weight of the cigar tobacco leaves to be fermented.
[0066] S2. The pretreated cigar tobacco leaves are tied into bundles of 30 pieces / bundle and fermented in a pile. The bundles are piled into a pile with a width of 2m, a height of 1.5m and a length of 4m. The water spraying liquid is evenly sprayed on the pile, and the pile is sprayed once each time the pile is turned. The amount of water sprayed accounts for 1.0% of the dry basis weight of the pretreated cigar tobacco leaves. The temperature of fermentation and turning the pile is controlled at 39°C.
[0067] In order to further demonstrate the effect of the fermentation method of the present invention for reducing the content of tobacco-specific nitrosamines in cigar tobacco by using tea polyphenols, the following experiment was conducted.
[0068] According to the fermentation methods of Examples 3 to 6 and the fermentation method of Comparative Example 1, the contents of N-nitrosonornicotine, 4-(N-methylnitrosamino)-1-(3-pyridyl)-1-butanone, N-nitrosoneanatabine, N-nitrosoanabasine and total nitrosamines were detected and recorded before and after spraying the tea polyphenol spray solution. The detection data are shown in Tables 1 to 4 below.
[0069] Table 1 Nitrosamine content in cigar tobacco leaves after fermentation with tea polyphenols aqueous solution
[0070]
[0071] Table 2 The decrease of nitrosamine content in tobacco leaves after fermentation with tea polyphenols aqueous solution
[0072]
[0073] Table 3 Nitrosamine content in finished cigars after adding tea polyphenols aqueous solution
[0074]
[0075] Table 4 The decrease of nitrosamine content in finished cigars after adding tea polyphenols aqueous solution
[0076]
[0077] During the fermentation of cigar tobacco leaves, microorganisms on the surface of the tobacco leaves reduce nitrates to nitrites, causing a large accumulation of nitrosamines in the tobacco leaves. From the above results, it can be seen that compared with the control of spraying clean water, that is, the cigar tobacco leaves in Comparative Example 1, the accumulation of nitrosamines in the fermented tobacco leaves of Examples 3 to 6 was significantly reduced by spraying different concentrations of tea polyphenol aqueous solutions, with a decrease of 14.32% to 52.34%. The nitrosamine content of the finished cigars made from fermented tobacco leaves as raw materials decreased by 5.98% to 49.23%, and as the concentration of tea polyphenols increased, the decrease in the nitrosamine content in the fermented tobacco leaves increased. Combined with Figure 2 and Figure 3 From the line graph, we can see that tea polyphenols have the greatest inhibitory effect on nitrosamines at 400μg / ml. The nitrosamine content in cigar tobacco leaves after fermentation can be reduced by up to 52.34%, and the cigar finished product can be reduced by 49.23%.
[0078] The method in Example 6 was adopted, wherein the pH during the fermentation process was 5.74, 3, 7, and 9, respectively, and the reduction of nitrosamines in cigar tobacco leaves and cigar finished products was recorded, respectively. The results are shown in Tables 5 to 8.
[0079] Table 5 Nitrosamine content in tobacco leaves after fermentation under different pH conditions
[0080]
[0081] Table 6 The decrease of nitrosamine content in tobacco leaves after fermentation under different pH conditions
[0082]
[0083] Table 7 Nitrosamine content in finished cigars after fermentation under different pH conditions
[0084]
[0085] Table 8 The decrease of nitrosamine content in finished cigars after fermentation under different pH conditions
[0086]
[0087] From the results in Tables 5 to 8, it can be seen that when the pH during the fermentation process is too low or too high, it will affect the reduction of nitrosamines in the final tobacco leaves and the finished cigars. This is mainly because strong acid or strong alkali conditions are not suitable for microbial growth, and cigar tobacco leaf fermentation mainly relies on the growth and metabolism of microorganisms. Therefore, cigar tobacco leaves cannot be fermented smoothly under strong acid or strong alkali conditions. Therefore, fermentation in a weak acid environment with a pH value of 5 to 6.5 is not only conducive to the growth of the dominant bacteria genus Bacillus, but Bacillus can inhibit the enzymes that grow molds, thereby inhibiting the production of molds, thereby effectively inhibiting the production of nitrate reductase by molds, and further reducing the content of nitrosamines.
[0088] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A fermentation method for reducing the nitrosamine content in cigar tobacco, characterized in that: The following steps are involved: Treating the cigar tobacco leaves to be fermented with a buffer solution to adjust the pH value of the cigar tobacco leaves to 5 to 6.5, thereby obtaining pretreated cigar tobacco leaves; The tea polyphenol aqueous solution is sprayed on the pretreated cigar tobacco leaves to obtain a fermentation mixture, and then fermented, and the tea polyphenols are used to inhibit the activity of nitrate reductase produced during the decomposition of the cigar tobacco leaves by microorganisms, so as to reduce the accumulation of nitrosamines; The concentration of the tea polyphenols aqueous solution is 100 μg / mL to 400 μg / mL; The spraying amount of the tea polyphenol aqueous solution accounts for 0.001% to 0.5% of the dry basis mass of the pretreated cigar tobacco leaves.
2. The fermentation method for reducing the nitrosamine content in cigar tobacco according to claim 1, characterized in that: The fermentation mixture further comprises, before fermentation: The cigar tobacco leaves in the fermentation mixture are tied into bundles of 30 to 35 leaves per bundle, and the bundles are piled into a pile for fermentation.
3. The fermentation method for reducing the nitrosamine content in cigar tobacco according to claim 2, characterized in that: The width of the smoke pile is 2m-2.5m, the height is 1.5m-1.8m, and the length is 4m-4.5m.
4. The fermentation method for reducing the nitrosamine content in cigar tobacco according to claim 2, characterized in that: The specific process of the fermentation is as follows: Turning the tobacco pile every 6 to 7 days, and spraying the tea polyphenols aqueous solution after each turning; The spraying amount of the tea polyphenols aqueous solution after each compost turning accounts for 0.001% to 0.5% of the dry basis weight of the cigar tobacco leaves to be fermented.
5. The fermentation method for reducing the nitrosamine content in cigar tobacco according to claim 1, characterized in that: The fermentation time is 35 to 42 days, and the temperature is 37° C. to 43° C.
6. The fermentation method for reducing the nitrosamine content in cigar tobacco according to claim 1, characterized in that: The buffer is a sodium bicarbonate buffer, and the concentration of the sodium bicarbonate buffer is 0.01 mol / L to 0.5 mol / L.
7. The fermentation method for reducing the nitrosamine content in cigar tobacco according to claim 6, characterized in that: The sodium bicarbonate buffer solution is obtained by mixing a Na2CO3 aqueous solution and a NaHCO3 aqueous solution in a volume ratio of 1 to 9:1 to 9; the concentration of the Na2CO3 solution is 0.01 mol / L to 0.5 mol / L; the concentration of the NaHCO3 solution is 0.01 mol / L to 0.5 mol / L.