Leaf moistening and redrying method for reducing pectin content of flue-cured tobacco and product thereof

Abstract

The invention relates to a leaf-moistening and re-drying method for reducing the pectin content of flue-cured tobacco and a product thereof, and the method comprises the following steps: detecting the initial pectin content in tobacco leaf raw materials, and then treating by adopting a specific leaf-moistening and re-drying process according to the tobacco leaf raw materials with different pectin contents, so that the pectin content in the flue-cured tobacco product is remarkably reduced, and the yield of the flue-cured tobacco product is improved. The method effectively reduces offensive odor substances in the flue-cured tobacco product, reduces loss of aroma substances in tobacco flakes, improves the content of aroma components, softens smoke, reduces irritation, improves smoking comfort, remarkably improves the quality of the flue-cured tobacco product, and has important significance in improving the processing level of tobacco leaf raw materials and the application value of the product.

Description

Technical Field

[0001] The invention belongs to the field of tobacco processing and relates to a leaf moistening and redrying method for reducing the pectin content of flue-cured tobacco and a product thereof. Background Art

[0002] Pectin is one of the unique components of plant cell walls, and its content in tobacco is about 5%-13%. During the growth of tobacco plants, pectin, cellulose, lignin, etc. together form plant cell walls to play a role in regulating water potential and resisting the invasion of pathogens. The pectin content in tobacco not only affects the physical and chemical properties of tobacco leaves, but also contributes to the aroma of cigarettes. However, when the proportion is too high, it will have a negative impact on the physical and chemical properties of tobacco, the taste and the safety of smoking.

[0003] Generally speaking, when the pectin content in tobacco leaves is high, the leaves will be relatively sensitive to changes in relative humidity. When the relative humidity is high, the leaves will absorb moisture and become soft, which will aggravate the natural heating phenomenon and even cause the leaves to mold. When the relative humidity is low, the leaves will dehydrate and become brittle and hard, and easy to break. Therefore, for tobacco products, pectin is a chemical component that has a negative impact on the quality of the taste. Pectin fermentation will produce up to 1-1.5% acetic acid, which can make tobacco products spicy and irritating, affecting the taste. At the same time, pectin will produce methanol when the leaves are burned, and methanol will be further oxidized into formaldehyde, formic acid and other components, which will not only increase the irritation of the smoke, but also be harmful to the human body when excessive. In addition, a high pectin content in tobacco leaves will also lead to an increase in the release of tar in cigarette smoke.

[0004] Therefore, how to provide a processing technology that can effectively reduce the pectin content in flue-cured tobacco has important application value. Summary of the invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a leaf moistening and redrying method for reducing the pectin content of flue-cured tobacco and a product thereof.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for moistening and redrying flue-cured tobacco leaves to reduce the pectin content, the method comprising the following steps:

[0008] (1) Detecting the pectin mass percentage in tobacco raw materials;

[0009] (2) performing primary and secondary moistening on the tobacco raw material, wherein the treatment conditions of the primary and secondary moistening are as follows:

[0010] When the mass percentage of pectin in the tobacco raw material is not less than 7.5%, for example, it can be 7.5%, 7.6%, 7.7%, 7.8%, 7.9%, 8%, 8.5%, 9%, 9.5%, 10%, etc.; the temperature of the first moistening leaf is 54-58°C, for example, it can be 54°C, 54.5°C, 55°C, 55.5°C, 56°C, 56.5°C, 57°C, 57.5°C, 58°C, etc.; the humidity is 18.50%-19.00%, for example, it can be 18.50%, 18.55%, 18.60%, 18.65%, 18.70%, 18.75%, 18.80%, 18.85%, 18.90 %, 18.95%, 19.00%, etc.; the temperature for secondary leaf moistening is 52.1-56°C, for example, it can be 52.1°C, 52.5°C, 53°C, 53.5°C, 54°C, 54.2°C, 54.5°C, 54.8°C, 55°C, 55.2°C, 55.5°C, 55.8°C, 56°C, etc.; the humidity is 17.80%-18.20%, for example, it can be 17.80%, 17.82%, 17.85%, 17.88%, 17.90%, 17.92%, 17.95%, 17.98%, 18.00%, 18.05%, 18.10%, 18.15%, 18.20%, etc.;

[0011] When the mass percentage of pectin in the tobacco raw material is 6.5%-7.5%, for example, it can be 6.5%, 6.6%, 6.8%, 6.9%, 7%, 7.2%, 7.5%, etc.; the temperature of the first moistening leaf is 51.1-55°C, for example, it can be 51.1°C, 51.5°C, 52°C, 52.5°C, 53°C, 53.5°C, 54°C, 54.5°C, 55°C, etc.; the humidity is 17.84%-18.13%, for example, it can be 17.84%, 17.88%, 17.90%, 17.92%, 17.95%, 17.98%, 18. 00%, 18.05%, 18.08%, 18.13%, etc.; the temperature for secondary leaf moistening is 49.1-52°C, for example, it can be 49.1°C, 49.5°C, 49.8°C, 50°C, 50.5°C, 51°C, 51.5°C, 51.8°C, 52°C, etc.; the humidity is 16.83%-17.23%, for example, it can be 16.83%, 16.90%, 16.92%, 16.95%, 16.98%, 17.00%, 17.05%, 17.10%, 17.15%, 17.18%, 17.20%, 17.23%, etc.;

[0012] When the mass percentage of pectin in the tobacco raw material is lower than 6.5%, it can be, for example, 6.5%, 6.4%, 6.3%, 6.2%, 6.1%, 6.0%, 5.9%, 5.8%, 5.5%, 5%, etc.; the temperature of the first moistening leaf is 47°C-51°C, for example, it can be 47°C, 47.5°C, 48°C, 48.5°C, 49°C, 49.5°C, 50°C, 50.5°C, 51°C, etc.; the humidity is 17.43%-17.83%, for example, it can be 17.43%, 17.48%, 17.50% , 17.53%, 17.58%, 17.63%, 17.73%, 17.83%, etc.; the temperature for secondary leaf moistening is 45-48°C, for example, it can be 45°C, 45.5°C, 46°C, 46.5°C, 47.5°C, 47.8°C, 48°C, etc.; the humidity is 16.43%-16.83%, for example, it can be 16.43%, 16.48%, 16.50%, 16.53%, 16.58%, 16.60%, 16.63%, 16.68%, 16.73%, 16.83%, etc.;

[0013] (3) Re-roasting the moistened tobacco leaves.

[0014] In the present invention, tobacco raw materials with different pectin contents are treated with specific leaf moistening processes, which significantly reduces the pectin content in flue-cured tobacco products and improves the quality of flue-cured tobacco products. When the temperature or humidity is higher than the above range, the overall cost of the entire processing and preparation process is greatly increased, which is not conducive to large-scale processing methods and processes; when the temperature or humidity is lower than the above range, the treatment effect of the pectin component in the flue-cured tobacco products becomes worse, and the quality of the final product decreases.

[0015] Preferably, the primary leaf moistening and secondary leaf moistening methods independently include any one or a combination of at least two of steam leaf moistening, soda-water mixed leaf moistening, moist hot air leaf moistening, dry hot air leaf moistening, and water spray leaf moistening;

[0016] Preferably, the one-time leaf moistening method is a combination of steam leaf moistening, dry hot air leaf moistening and water spray leaf moistening;

[0017] Preferably, the secondary leaf moistening method is a combination of steam leaf moistening, hot and humid air leaf moistening and water spray leaf moistening.

[0018] The present invention also creatively discovered that different leaf moistening methods have different treatment effects on the pectin content in tobacco raw materials. When the first leaf moistening and the second leaf moistening are respectively performed using the above-mentioned specific modes, the treatment effect on reducing the pectin in the flue-cured tobacco is better.

[0019] Preferably, the re-roasting is leaf beating and re-roasting.

[0020] Preferably, the leaf threshing and re-drying comprises preheating, drying, cooling and moisture conditioning treatments performed in sequence.

[0021] Preferably, in the re-roasting process, the conveying speed of the tobacco material is 15Hz-40Hz, for example, it can be 15Hz, 18Hz, 20Hz, 22Hz, 25Hz, 28Hz, 30Hz, 32Hz, 35Hz, 40Hz, etc. Other specific point values ​​within the numerical range can be selected, and they will not be described here one by one.

[0022] Preferably, the preheating treatment comprises microwave heating and drying.

[0023] The microwave preheating treatment method adopted in the present invention can effectively reduce the content of pectin in the tobacco leaf raw material, reduce impurities, and improve the quality of flue-cured tobacco products.

[0024] Preferably, the output power of the microwave heating drying is 60-80kW, for example, it can be 60kW, 62kW, 65kW, 68kW, 70kW, 72kW, 75kW, 78kW, 80kW, etc. Other specific point values ​​within this numerical range can be selected, which will not be described here one by one.

[0025] Preferably, the drying is a gradient temperature drying, and the first drying, the second drying and the third drying treatment are performed in sequence. The specific processing steps are as follows:

[0026] The first drying temperature is 42-57°C, for example, it can be 42°C, 45°C, 48°C, 50°C, 51°C, 52°C, 55°C, 56°C, 57°C, etc.; the second drying temperature is 58-70°C, for example, it can be 58°C, 59°C, 60°C, 62°C, 65°C, 67°C, 68°C, 70°C, etc.; the third drying temperature is 50-58°C, for example, it can be 50°C, 51°C, 52°C, 53°C, 55°C, 56°C, 58°C, etc. Other specific point values ​​within this numerical range can be selected, so they will not be described one by one here.

[0027] In the present invention, a step-by-step temperature increase is adopted during the re-baking process, which can effectively reduce the loss of aroma substances in the tobacco leaves, increase the content of aroma components, and further improve the quality and taste of flue-cured tobacco products while fully reducing the pectin content level in the flue-cured tobacco.

[0028] Preferably, the cooling temperature is 32-38°C, for example, it can be 32°C, 32.5°C, 33°C, 33.5°C, 34°C, 34.5°C, 35°C, 35.5°C, 36°C, 37°C, 38°C, etc. Other specific point values ​​within this numerical range can be selected, and they will not be described here one by one.

[0029] Preferably, the moisture conditioning treatment is a vacuum moisture conditioning treatment.

[0030] Preferably, the temperature of the vacuum tempering treatment is 25-35°C, for example, it can be 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 34°C, 35°C, etc.; the time is 10-20min, for example, it can be 10min, 12min, 14min, 15min, 16min, 18min, 19min, 20min, etc., and other specific point values ​​within the numerical range can be selected, which will not be elaborated here.

[0031] In a second aspect, the present invention provides a tobacco product made according to the leaf moistening and redrying method described in the first aspect.

[0032] Preferably, the tobacco product comprises tobacco sheets, tobacco shreds or cigarettes.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention provides a leaf moistening and re-drying method capable of reducing the pectin content of flue-cured tobacco. Tobacco raw materials with different pectin contents are respectively processed by specific leaf moistening processes, thereby significantly reducing the pectin content in the flue-cured tobacco products, effectively reducing foreign gas substances in the flue-cured tobacco products, and improving the quality of the flue-cured tobacco products. DETAILED DESCRIPTION

[0035] In order to further explain the technical means and effects adopted by the present invention, the technical solution of the present invention is further described below in conjunction with the preferred embodiments of the present invention, but the present invention is not limited to the scope of the embodiments.

[0036] Example 1

[0037] This embodiment provides a flue-cured tobacco product with low pectin content, and the preparation method thereof is as follows:

[0038] (1) The upper tobacco leaves of Yunnan Baoshan Honghua Dajinyuan B1F first-cured tobacco leaves in 2022 were collected as tobacco leaf raw materials, and the pectin content in the tobacco leaf raw materials was determined by the method in YC / T 346-2010. The raw materials with a pectin content of not less than 7.5% were classified as high-pectin tobacco leaves; the raw materials with a pectin content of 6.5%-7.5% were classified as medium-pectin tobacco leaves; the raw materials with a pectin content of less than 6.5% were classified as low-pectin tobacco leaves;

[0039] (2) Moisturizing leaves: the specific conditions are:

[0040]

[0041] (3) Re-baking, the specific conditions are as follows:

[0042] ①The conveying speed of tobacco leaf material is 30Hz;

[0043] ② Microwave preheating, output power is 70kW;

[0044] ③ Gradient hot air drying: first drying (45°C), second drying (62°C), third drying (52°C);

[0045] ④ Cooling (36°C);

[0046] ⑤ Vacuum rehumidification, temperature is 30℃, time is 15min;

[0047] (4) After the rehumidification is completed, the tobacco is collected to obtain the flue-cured tobacco product with a low pectin content.

[0048] Example 2

[0049] This embodiment provides a flue-cured tobacco product with a low pectin content, and the preparation method thereof is as follows:

[0050] (1) The upper tobacco leaves of Yunnan Baoshan Honghua Dajinyuan B2F first-cured tobacco leaves in 2022 were collected as tobacco leaf raw materials, and the pectin content in the tobacco leaf raw materials was determined by the method in YC / T 346-2010. The raw materials with a pectin content of not less than 7.5% were classified as high-pectin tobacco leaves; the raw materials with a pectin content of 6.5%-7.5% were classified as medium-pectin tobacco leaves; the raw materials with a pectin content of less than 6.5% were classified as low-pectin tobacco leaves;

[0051] (2) Moisturizing leaves: the specific conditions are:

[0052]

[0053] (3) Re-baking, the specific conditions are as follows:

[0054] ①The conveying speed of tobacco materials is 40Hz;

[0055] ② Microwave preheating, output power is 78kW;

[0056] ③ Gradient hot air drying: first drying (50°C), second drying (58°C), third drying (55°C);

[0057] ④ Cooling (32°C);

[0058] ⑤ Vacuum rehumidification, temperature is 27℃, time is 18min;

[0059] (4) After the rehumidification is completed, the tobacco is collected to obtain the flue-cured tobacco product with a low pectin content.

[0060] Example 3

[0061] This embodiment provides a flue-cured tobacco product with a low pectin content, and the preparation method thereof is as follows:

[0062] (1) The upper tobacco leaves of Yunyan 116 first-cured tobacco leaves planted in Baoshan in 2024 were collected as tobacco raw materials, and the pectin content in the tobacco raw materials was determined by the method in YC / T346-2010. The raw materials with a pectin content of not less than 7.5% were classified as high-pectin tobacco leaves; the raw materials with a pectin content of 6.5%-7.5% were classified as medium-pectin tobacco leaves; the raw materials with a pectin content of less than 6.5% were classified as low-pectin tobacco leaves;

[0063] (2) Moisturizing leaves: the specific conditions are:

[0064]

[0065] (3) Re-baking, the specific conditions are as follows:

[0066] ①The conveying speed of tobacco materials is 18Hz;

[0067] ② Microwave preheating, output power is 60kW;

[0068] ③ Gradient hot air drying: first drying (55°C), second drying (68°C), third drying (57°C);

[0069] ④ Cooling (37°C);

[0070] ⑤ Vacuum rehumidification, temperature is 32℃, time is 12min;

[0071] (4) After the rehumidification is completed, the tobacco is collected to obtain the flue-cured tobacco product with a low pectin content.

[0072] Example 4

[0073] This embodiment provides a flue-cured tobacco product with a low pectin content, using the groups of tobacco leaf raw materials in Example 1. The preparation method thereof is different from that in Example 1 only in that the leaf moistening is performed once using "dry hot air + water spraying", and the remaining processing steps and process parameters are all referred to Example 1.

[0074] Example 5

[0075] This embodiment provides a flue-cured tobacco product with a low pectin content, using the groups of tobacco leaf raw materials in Example 1. The preparation method thereof is different from that in Example 1 only in that the leaf moistening is performed once using "steam + water spraying", and the remaining processing steps and process parameters are all referred to Example 1.

[0076] Example 6

[0077] This embodiment provides a flue-cured tobacco product with a low pectin content, using the groups of tobacco leaf raw materials in Example 1. The only difference between its preparation method and that in Example 1 is that the secondary leaf moistening adopts "wet hot air + water spraying leaf moistening", and the remaining processing steps and process parameters are all referred to Example 1.

[0078] Example 7

[0079] This embodiment provides a flue-cured tobacco product with a low pectin content, using the groups of tobacco leaf raw materials in Example 1. The preparation method thereof is different from that in Example 1 only in that the secondary leaf moistening adopts "steam + water spraying leaf moistening", and the remaining processing steps and process parameters are all referred to Example 1.

[0080] Example 8

[0081] This embodiment provides a flue-cured tobacco product with a low pectin content, which uses the groups of tobacco leaves as raw materials after moisturizing in Example 1. The preparation method thereof is different from that of Example 1 only in that the moisturized tobacco leaves are directly subjected to gradient hot air drying without microwave preheating treatment, and the remaining processing steps and process parameters are all referred to Example 1.

[0082] Example 9

[0083] This embodiment provides a flue-cured tobacco product with a low pectin content, which uses the groups of tobacco leaf raw materials after moisturizing in Example 1. The only difference between its preparation method and that of Example 1 is that the first, second and third drying temperatures in the gradient hot air drying process are all 62°C, and the remaining processing steps and process parameters are all referred to Example 1.

[0084] Comparative Example 1

[0085] This embodiment provides a flue-cured tobacco product with low pectin content, using the tobacco leaf raw material in Example 1. The preparation method thereof is different from that in Example 1 only in the leaf moistening conditions, which are as follows:

[0086]

[0087] Comparative Example 2

[0088] This embodiment provides a flue-cured tobacco product with a low pectin content, using the tobacco leaf raw material in Example 2. The preparation method thereof is different from that in Example 2 only in that the leaf moistening conditions use the leaf moistening conditions in Comparative Example 1.

[0089] Comparative Example 3

[0090] This embodiment provides a flue-cured tobacco product with a low pectin content, using the tobacco leaf raw material in Example 3. The preparation method thereof is different from that in Example 3 only in that the leaf moistening conditions use the leaf moistening conditions in Comparative Example 1.

[0091] Test Example 1

[0092] The pectin content of the tobacco leaves in the flue-cured tobacco products prepared in Examples 1-9 and Comparative Examples 1-3 was tested. The test method was based on the method in YC / T 346-2010. The test results are shown in Table 1.

[0093] Table 1

[0094]

[0095]

[0096] From the data in the table, we can see that:

[0097] (1) It can be seen from Examples 1 to 3 that the present invention subjects tobacco raw materials with different pectin contents to specific leaf moistening and redrying processes, which significantly reduces the pectin content in flue-cured tobacco products, effectively reduces foreign matter in the flue-cured tobacco products, and improves the quality of the flue-cured tobacco products.

[0098] (2) By comparing Example 1 with Examples 4-7, it can be seen that the present invention uses a specific mode of primary and secondary moisturizing to treat the primary flue-cured tobacco leaves, which can further reduce the pectin content in the flue-cured tobacco products, reduce impurities, and improve the aroma and smoking quality.

[0099] (3) By comparing Example 1 with Examples 8-9, it can be seen that the present invention uses a specific microwave preheating treatment combined with a specific gradient temperature drying process in the re-drying process, which can further improve the treatment effect on tobacco leaves and further reduce the pectin content in flue-cured tobacco sheets.

[0100] (4) By comparing Examples 1-3 with Comparative Examples 1-3, it can be seen that when the temperature and humidity of the leaf moistening treatment are not within the specific range of the present invention, the effect of reducing the pectin content in the flue-cured tobacco products prepared therefrom is not as good as that of the flue-cured tobacco products in Examples 1-3. It can be seen that the present invention adopts specific leaf moistening methods according to the pectin content of different tobacco leaves, which can significantly reduce the pectin content in the final flue-cured tobacco products and prepare flue-cured tobacco products with better smoking quality.

[0101] Test Example 2

[0102] The flue-cured tobacco products (medium pectin tobacco leaves) prepared in Examples 1-9 and Comparative Examples 1-3 were made into cigarettes according to the process standards, and the cigarettes were subjected to sensory evaluation (smoke characteristics) scoring according to the "Method for Sensory Evaluation of Chinese Cigarette Style" (YC / T 497-2014). Ten people participated in the evaluation, and the results are shown in Table 2

[0103] Table 2

[0104]

[0105]

[0106] It can be seen from the data in the table that the present invention uses a specific leaf moistening process to process tobacco raw materials with different initial pectin content, which significantly reduces the pectin content in the flue-cured tobacco products, effectively reduces the impurities in the flue-cured tobacco products, softens the smoke, reduces irritation, improves smoking comfort, and significantly improves the quality of flue-cured tobacco products.

[0107] In summary, the present invention provides a leaf moistening and re-drying method that can reduce the pectin content of flue-cured tobacco. Tobacco raw materials with different pectin contents are treated with specific leaf moistening processes, which significantly reduces the pectin content in the flue-cured tobacco products, effectively reduces the foreign matter in the flue-cured tobacco products, and improves the quality of the flue-cured tobacco products.

[0108] The applicant declares that the present invention illustrates the technical solution of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0109] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0110] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for moistening and redrying flue-cured tobacco leaves to reduce the pectin content of flue-cured tobacco, characterized in that: The method comprises the following steps: (1) Detecting the pectin mass percentage in tobacco raw materials; (2) performing primary and secondary moistening on the tobacco raw material, wherein the treatment conditions of the primary and secondary moistening are as follows: When the mass percentage of pectin in the tobacco raw material is not less than 7.5%, the temperature of the first moistening is 54-58°C, the humidity is 18.50%-19.00%, and the temperature of the second moistening is 52.1-56°C, the humidity is 17.80%-18.20%; When the mass percentage of pectin in the tobacco raw material is 6.5%-7.5%, the temperature of the first moistening is 51.1-55°C, the humidity is 17.84%-18.13%, and the temperature of the second moistening is 49.1-52°C, the humidity is 16.83%-17.23%; When the mass percentage of pectin in the tobacco raw material is lower than 6.5%, the temperature of the first moistening is 47-51°C, the humidity is 17.43%-17.83%, and the temperature of the second moistening is 45-48°C, the humidity is 16.43%-16.83%; (3) Re-roasting the moistened tobacco leaves.

2. The method for moistening and redrying flue-cured tobacco leaves to reduce the pectin content according to claim 1, characterized in that: The primary and secondary leaf moistening methods independently include any one or a combination of at least two of steam leaf moistening, soda-water mixed leaf moistening, moist hot air leaf moistening, dry hot air leaf moistening, and water spray leaf moistening; Preferably, the one-time leaf moistening method is a combination of steam leaf moistening, dry hot air leaf moistening and water spray leaf moistening; Preferably, the secondary leaf moistening method is a combination of steam leaf moistening, hot and humid air leaf moistening and water spray leaf moistening.

3. The method for moistening and redrying flue-cured tobacco leaves to reduce pectin content according to claim 1, characterized in that: The re-roasting is leaf beating and re-roasting; Preferably, the leaf threshing and re-drying comprises preheating, drying, cooling and moisture conditioning treatments performed in sequence.

4. The method for moistening and redrying flue-cured tobacco leaves to reduce pectin content according to claim 1 or 3, characterized in that: During the redrying process, the conveying speed of the tobacco leaf material is 15Hz-40Hz.

5. The method for moistening and redrying flue-cured tobacco leaves to reduce pectin content according to claim 3, characterized in that: The preheating treatment method includes microwave heating and drying; Preferably, the output power of the microwave heating drying is 60-80 kW.

6. The method for moistening and redrying flue-cured tobacco leaves to reduce pectin content according to claim 3, characterized in that: The drying is a gradient temperature drying, and the first drying, the second drying and the third drying treatment are performed in sequence. The specific processing steps are as follows: The temperature of the first drying is 42-57°C, the temperature of the second drying is 58-70°C, and the temperature of the third drying is 50-58°C.

7. The method for moistening and redrying flue-cured tobacco leaves to reduce pectin content according to claim 3, characterized in that: The cooling temperature is 32-38°C.

8. The method for moistening and redrying flue-cured tobacco leaves to reduce pectin content according to claim 3, characterized in that: The moisture regain treatment is a vacuum moisture regain treatment; Preferably, the temperature of the vacuum conditioning treatment is 25-35°C and the time is 10-20 minutes.

9. A tobacco product made by the leaf moistening and redrying method according to any one of claims 1 to 8.

10. The tobacco product according to claim 9, characterized in that The tobacco products include tobacco slices, tobacco shreds or cigarettes.

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