A method and use for irradiating and modulating sun-cured tobacco

Abstract

The present invention discloses a method for using irradiation to modulate sun-cured tobacco, comprising the following steps: (1) After the fresh tobacco leaves are sun-dried, they are soaked in water for a period of time and then dried; (2) The pretreatment liquid is evenly sprayed on the surface of the tobacco leaves after soaking and drying, and then sealed for natural fermentation for a period of time; (3) The fermented tobacco leaves are sun-dried again; (4) The tobacco leaves after re-sun-drying are irradiated with a certain dose of γ-rays; (5) The irradiated tobacco leaves are naturally aged and ripened under certain conditions to obtain the sun-cured tobacco. The present invention also discloses the use of the sun-cured tobacco obtained by the above method for improving the quality of cigarette smoke.

Description

Technical Field

[0001] The present invention belongs to the technical field of tobacco fermentation processes. Specifically, it relates to a technical method and use for improving the quality of sun-cured tobacco using irradiation. Background Art

[0002] The process of tobacco leaf modulation is a relatively complex physiological and biochemical process. There have been many reports on the research of the tobacco leaf modulation process, and the research results are also remarkable. These results have also played an important role in the production of high-quality and characteristic tobacco. However, there are still many problems in the tobacco leaf modulation process. Because the tobacco leaf modulation process is not only restricted by its own internal factors, but also affected by external environmental temperature, humidity, air, and various enzymes and microorganisms. Different tobacco types modulated by different modulation methods have very different environments, which have a great impact on the internal chemical reactions of tobacco leaves. The result is bound to have a great impact on the modulation quality of tobacco leaves, thereby changing the quality of the modulated tobacco leaves and the final usability.

[0003] Sun-cured tobacco is obtained by naturally drying fresh tobacco leaves. However, sun-cured tobacco leaves are green and have a strong miscellaneous odor, a strong pungency and irritation, resulting in a non-soft smoke, a monotonous aroma quality and insufficient aroma quantity, etc., and still do not meet the quality requirements for direct industrial processing. Under natural conditions or suitable conditions with artificial enhancement, the quality of raw tobacco can be improved to varying degrees after a period of fermentation. However, although the fermentation of sun-cured tobacco reduces the strong pungency and irritation, the aroma and aroma quantity of the smoke are insufficient, the strength is weak, and the aftertaste is not pure enough; it still does not meet the quality requirements for industrial processing.

[0004] The present invention is proposed to solve the above problems. Summary of the Invention

[0005] In order to overcome the problems existing in sun-cured tobacco in the background art, the present invention provides a method for modulating sun-cured tobacco using irradiation. The method of the present invention fully dries fresh tobacco leaves and then uses irradiation to assist the fermentation, re-drying, purification and aging of the tobacco leaves. The obtained tobacco leaves have significantly reduced green and miscellaneous odors, have a natural sweet and mellow aroma and a baking aroma, a rich aroma rhyme, a better strength of the smoke, significantly improved aroma quantity and comfort, a purer smoke taste, a better taste, and a higher sense of satisfaction; the smoke quality is significantly improved.

[0006] The technical solution of the present invention is as follows:

[0007] The first aspect of the present invention discloses a method for modulating sun-cured tobacco using irradiation, comprising the following steps:

[0008] (1) After drying fresh tobacco leaves, soak them in water for a period of time and then dry them.

[0009] (2) Evenly spray the pretreatment liquid on the surface of the tobacco leaves after soaking and drying, and seal them for natural fermentation for a period of time.

[0010] (3) Redry the fermented tobacco leaves.

[0011] (4) Irradiate the redried tobacco leaves with a certain dose of γ-rays.

[0012] (5) Naturally age and ripen the irradiated tobacco leaves under certain conditions to obtain the sun-cured tobacco described.

[0013] Preferably, the water content of the tobacco leaves before soaking in step (1) does not exceed 12 wt%, and the soaking time is 30 - 60 min.

[0014] Preferably, the preparation method steps of the pretreatment liquid in step (2) are as follows:

[0015] (A) Prepare an ethanol solution with a concentration of 0.5 - 5 wt%; preferably 1 - 1.5 wt%.

[0016] (B) Add salt to the ethanol solution in step (A) according to a mass ratio of 0.5 - 5.0 wt% and dissolve it to obtain the pretreatment liquid; the concentration of the salt is preferably 1 - 2.5 wt%.

[0017] Preferably, the salts in step (B) include: one or a mixture of two or more of sodium chloride, sodium carbonate, sodium lactate, sodium oxalate, sodium alginate, sodium benzoate, potassium citrate, potassium sorbate, methyl lactate, potassium carbonate, potassium phosphate.

[0018] Preferably, the temperature of natural fermentation in step (2) is 90 - 100 °C, and the fermentation time is 2 - 5 days; the water content of the tobacco leaves during fermentation is not less than 30 wt%.

[0019] Preferably, the irradiation in step (4) uses 60 Coγ for irradiation, the irradiation dose is 1.0 - 30.0 kGy, and the irradiation time is 5 min - 120 min; the water content of the tobacco leaves during irradiation is not less than 12 wt%.

[0020] Preferably, the water content of the tobacco leaves during the natural aging and ripening stage in step (5) is maintained at 12 - 15 wt%.

[0021] Preferably, the relative air humidity during the natural aging and ripening in step (5) is 45 - 55%, and the temperature is room temperature; the time of natural aging and ripening is not less than 30 days.

[0022] The second aspect of the present invention discloses the use of the sun-cured tobacco obtained by the method described above for improving the quality of cigarette smoke.

[0023] Advantages of the present invention:

[0024] 1. The method of the present invention involves fully sun-drying fresh tobacco leaves, followed by irradiating to assist in tobacco leaf fermentation, and then sun-drying, purifying, and aging. The resulting tobacco leaves have a natural mellow and sweet aroma and a baking aroma; the green and miscellaneous odors of the tobacco leaves are significantly reduced, the aroma is more intense, the aroma quantity and comfort are significantly improved, the strength is good, the smoke taste is purer, the taste is better, and the satisfaction is higher; the smoke quality is significantly improved.

[0025] 2. The method of the present invention uses a pretreatment solution to spray and soak the tobacco leaves for natural fermentation, removing the pungent taste and reducing the irritation. The fermentation of the present invention is natural fermentation and does not require the addition of microorganisms.

[0026] 3. The method of the present invention further ages and mellows the irradiated tobacco leaves for a certain period of time. The resulting sun-cured tobacco has a rich smoke aroma, improves the aroma quantity and comfort, has a good strength, a pure aftertaste, significantly reduced green and miscellaneous odors, a purer smoke taste, and a higher satisfaction.

[0027] 4. The method of the present invention can effectively reduce the nitrogenous harmful components of sun-cured tobacco while improving the quality of tobacco leaves; it can effectively improve the utilization rate of sun-cured tobacco.

[0028] 5. The method of the present invention provides a new idea for the modulation of sun-cured tobacco. Specific Embodiments

[0029] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the given embodiments are only for helping to understand the present invention and should not be regarded as specific limitations of the present invention. The processes, conditions, reagents, experimental methods, etc., except for the specifically mentioned content below, are all common knowledge and well-known common sense in the art, and the present invention has no special limitations. The experimental methods without specific conditions indicated in each embodiment are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise stated, the meanings of all professional terms and scientific terms used in this specification are the same as those generally understood by those skilled in the technical field to which the present invention belongs. However, in case of conflict, the present specification including the definitions shall prevail.

[0030] Example 1:

[0031] The steps for preparing the pretreatment solution are as follows:

[0032] (A) Prepare an ethanol solution with a concentration of 1 wt%.

[0033] (B) Add sodium chloride to the above ethanol solution according to a mass ratio of 1.5 wt% and dissolve it to obtain the pretreatment solution.

[0034] The steps for irradiating and modulating sun-cured tobacco are as follows:

[0035] (1) After fully sun-drying fresh tobacco leaves, the water content of the tobacco leaves is made to be 10 wt%; soak them in water for 40 min;

[0036] (2) Evenly spray the pre-treatment liquid on the tobacco leaves dried after soaking in step (1), and ferment at 90 °C for 2 days; the water content of the tobacco leaves during fermentation is 30 wt%;

[0037] (3) Sun-dry the fermented tobacco leaves for another 10 days to make the water content of the tobacco leaves 15 wt%;

[0038] (4) Irradiate the tobacco leaves after sun-drying again with 5 kGy 60 Coγ for 15 min;

[0039] (5) Put the tobacco leaves after sun-drying again into natural aging and aging for 30 days, with the relative air humidity of 50% and the temperature of room temperature 30 °C; then the sun-cured tobacco is obtained.

[0040] Comparative Example 1: The same as Example 1, the difference is that there is no step (2) of spraying the pre-treatment liquid and the natural fermentation step.

[0041] Comparative Example 2: The same as Example 1, the difference is that there is no step (4) of irradiation step.

[0042] Comparative Example 3: The same as Example 1, but there is no spraying of the pre-treatment liquid in step (2).

[0043] Comparative Example 4: The same as Example 1, but there is no step (5) of natural aging and aging step.

[0044] Make the sun-cured tobacco obtained in Example 1 and Comparative Examples 1-4 into cigarettes, and conduct sensory evaluation by the 9-point evaluation method. The sensory evaluation results are shown in Table 1.

[0045] Table 1 Smoking evaluation results of different sun-cured tobaccos

[0046] Treatment Aroma quantity (9) Off-flavor (9) Concentration (9) Strength (9) Irritation (9) Aftertaste (9) Total score Example 1 8.5 8.0 8.0 7.5 8.5 8.5 49.0 Comparative Example 1 6.5 5.5 6.0 7.0 5.0 6.5 36.5 Comparative Example 2 6.9 5.0 6.5 7.0 7.0 5.0 38.5 Comparative Example 3 7.0 6.0 7.5 7.5 6.5 6.0 40.5 Comparative Example 4 7.5 7.0 7.5 7.5 7.0 7.0 43.5

[0047] It can be seen from the smoking evaluation results in Table 1 that the sun-cured tobacco obtained in Example 1 has the best sensory quality, better aroma quality, especially with mellow and sweet aroma and baking aroma, and the aroma is more intense; the sun-cured tobacco obtained has less off-flavor in the smoke, rich tobacco aroma, good concentration, moderate strength, less off-flavor, relatively pure and comfortable aftertaste, more pure tobacco flavor, and higher satisfaction. The sun-cured tobacco in Comparative Example 1 without spraying the pre-treatment liquid and the natural fermentation step has more off-flavor and irritation in the smoke, and the concentration is insufficient. The off-flavor in the smoke of the sun-cured tobacco in Comparative Example 2 without the irradiation step is very obvious, the pungency is prominent, and the aftertaste is the worst. The off-flavor, irritation and aftertaste of the sun-cured tobacco in Comparative Example 3 without spraying the pre-treatment liquid are poor. The comprehensive performance of the sun-cured tobacco obtained in Comparative Example 4 without the aging and aging steps is also good, but the mellow and sweet aroma rhyme of the smoke is not enough, and the off-flavor and aftertaste are not as good as those of the sun-cured tobacco obtained with the natural aging and aging steps.

[0048] The chemical composition indexes of the tobacco leaves obtained in Example 1 and Comparative Examples 1-4, such as water-soluble sugar, total nitrogen, nicotine, potassium, chlorine, nitrate, etc., were detected. The detection methods and bases are shown in Table 2, and the detection results are shown in Table 3.

[0049] Table 2 Detection items and bases of the internal chemical components of tobacco leaves

[0050] Test items Name and number of the standard (method) based on which the test is conducted Total sugar Determination of water-soluble sugar in tobacco and tobacco products - Continuous flow method (YC / T 159-2002) Total nitrogen Determination of total nitrogen in tobacco and tobacco products - Continuous flow method (YC / T 161-2002) Nicotine Determination of total alkaloids in tobacco and tobacco products - Continuous flow potassium thiocyanate method (YC / T 468-2013) Chloride ion Determination of chlorine content in tobacco and tobacco products - Continuous flow method (YC / T 162-2011) Potassium Determination of potassium in tobacco and tobacco products - Flame photometry method YC / T 173-2003 Nitrate Determination of nitrate in tobacco and tobacco products - Continuous flow method YC / T 296—2009

[0051] Table 3 Contents of the internal chemical components of tobacco leaves

[0052] Raw material name Total nitrogen % Nicotine % Water-soluble sugar % Potassium % Chlorine % Example 1 3.07 2.21 3.08 2.24 0.73 Comparative Example 1 3.65 3.67 3.03 2.91 0.71 Comparative Example 2 4.14 4.59 1.63 2.88 0.78 Comparative Example 3 3.79 3.15 2.38 2.76 0.74 Comparative Example 4 3.37 3.23 2.59 2.83 0.77

[0053] It can be seen from Table 3 that the content of water-soluble sugar in the irradiated tobacco leaves increased significantly, reaching up to 89%, while there was no significant difference in the contents of total nitrogen, nicotine, potassium and chlorine before and after irradiation. Thus, it shows that after irradiation, the sugar-alkali ratio increased significantly, making the tobacco taste more mellow, the irritation reduced, the green and miscellaneous odors significantly reduced, and the smoking taste improved.

[0054] The total nitrogen of the tobacco leaves obtained in Example 1 and Comparative Examples 1-4 was analyzed, and the results are shown in Table 4.

[0055] Table 4 Detection results of TSNAs content

[0056] Raw material name NNN (μg / g) NNK (μg / g) NAT (μg / g) NAB (μg / g) Total TSNAs (μg / g) Example 1 0.06 0.16 0.13 - 0.36 Comparative Example 1 0.09 0.22 0.18 - 0.50 Comparative Example 2 0.11 0.41 0.30 0.01 0.83 Comparative Example 3 0.08 0.17 0.21 - 0.47 Comparative Example 4 0.06 0.20 0.16 - 0.43

[0057] It can be seen from the results in Table 4 that the TSNAs content in the irradiated tobacco leaves of Example 1 and Comparative Examples 1, 3 and 4 was lower than that in the non-irradiated tobacco leaves of Comparative Example 2. Among them, the degradation rate of TSNAs in the tobacco leaves of Example 1 relative to the non-irradiated tobacco leaves of Comparative Example 2 reached 57%, and the degradation rate of NNK reached 61%. Therefore, the effect of reducing harmful nitrogen-containing components by using irradiation to modulate sun-cured tobacco in the present invention is obvious.

[0058] The embodiments are only preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for irradiating and modulating sun-cured tobacco, characterized in that, It includes the following steps: (1) After drying the fresh tobacco leaves in the sun, soak them in water for a period of time and then dry them; (2) Evenly spray the pretreatment liquid on the surface of the tobacco leaves after soaking and drying, and seal them for natural fermentation for a period of time; (3) Dry the fermented tobacco leaves in the sun again; (4) Irradiate the re-dried tobacco leaves with a certain dose of γ-rays; the irradiation uses 60 Co γ for irradiation, the irradiation dose is 1.0 - 30.0 kGy, and the irradiation time is 5 min - 120 min; the water content of the tobacco leaves during irradiation is not less than 12 wt%; (5) Naturally age and ripen the irradiated tobacco leaves under certain conditions to obtain the sun-cured tobacco; The preparation method steps of the pretreatment liquid in step (2) are: (A) Prepare an ethanol solution with a concentration of 0.5 - 5.0 wt%; (B) Add salt to the ethanol solution in step (A) according to a mass ratio of 0.5 - 5.0 wt% and dissolve it to obtain the pretreatment liquid; the salt includes one or a mixture of two or more of sodium chloride, sodium carbonate, sodium lactate, sodium oxalate, sodium alginate, sodium benzoate, potassium citrate, potassium sorbate, methyl lactate, potassium carbonate, potassium phosphate.

2. The method according to claim 1, characterized in that The water content of the tobacco leaves before soaking in step (1) does not exceed 12 wt%, and the soaking time is 30 - 60 min.

3. The method according to claim 1, characterized in that, The temperature of natural fermentation in step (2) is 90 - 100 °C, and the fermentation time is 2 - 5 days; the water content of the tobacco leaves during fermentation is not less than 30 wt%.

4. The method according to claim 1, wherein The water content of the tobacco leaves in the natural aging and ripening stage in step (5) is maintained at 12 - 15 wt%.

5. The method according to claim 1, wherein The relative air humidity during natural aging and ripening in step (5) is 45 - 55%, and the temperature is room temperature; the time of natural aging and ripening is not less than 30 days.

6. Use of the sun-cured tobacco obtained by the method according to any one of claims 1 - 5 for improving the quality of tobacco smoke.