Tobacco leaf fermentation method and fermented tobacco leaf

Abstract

The invention relates to a tobacco leaf fermentation method and fermented tobacco leaves. The tobacco leaf fermentation method comprises the following steps: regaining moisture of blended cigar tobacco leaves to balance moisture; mixing the cigar tobacco leaves subjected to moisture balance with the sugarcane water, and standing to prepare an intermediate mixture; the intermediate mixture is placed at the temperature of 35-52 DEG C for fermentation treatment, and after redrying, the fermented tobacco leaves are prepared. Wherein the sugarcane water is added to perform aroma-enhancing and quality-improving fermentation on the cigar tobacco leaves, and under the specific fermentation process, the problems that existing cigars are high in irritation, unclean in aftertaste, residual in oral cavity and the like are solved, so that the content of aroma components such as alcohols, aldehydes and ketones, esters, alkanes and aromatics in the cigar tobacco leaves is remarkably increased, and the quality of the cigar tobacco leaves is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tobacco processing, in particular to a tobacco leaf fermentation method and fermented tobacco leaf. BACKGROUND

[0002] Cigar is a special tobacco product, and the main producing countries are Cuba, Dominican Republic, Honduras, China and the like. Cigar tobacco leaves will have some astringent taste, bitter taste and other undesirable tastes after being picked. The fermentation process is like a screening and purification process, and through the activities of microorganisms and chemical reactions, these unpleasant tastes will gradually decrease. For example, some undesirable odor components produced by the decomposition of proteins and chlorophyll in fresh tobacco leaves will be transformed or volatilized under fermentation conditions. Fermentation can produce new flavor substances. During the fermentation process, the components such as sugars and amino acids in the tobacco leaves will undergo Maillard reaction. This reaction is similar to the process of food surface color deepening and flavor generation in the cooking process, and it can generate a series of complex flavor compounds such as furans and pyrazines. These substances endow cigar with unique roasted, nutty, sweet and other rich flavors.

[0003] Traditional technologies disclose the use of hops for tobacco flavoring; another traditional technology discloses that the proteinase solution is sprayed on the modulated tobacco core leaves and subjected to fermentation treatment, which can effectively degrade the proteins in the tobacco leaves and transform the sugar in the tobacco leaves, thereby improving and enhancing the aroma quality, aroma amount, reducing the irritation and other quality indicators of the tobacco leaves; another traditional technology discloses that the tobacco leaves are treated and fermented with soybean paste juice, which utilizes the aroma precursor generated in the frying process of soybean paste to provide a microbial substrate for the fermentation process of cigar tobacco leaves, and enhances the flavor aroma of cigar tobacco leaves. However, due to the influence of ecological conditions and production processes, there are still some problems in the quality of traditional cigar tobacco leaves, which are specifically manifested in the aspects of obvious pungent odor and irritation, low aroma richness and the like.

[0004] Therefore, the traditional technology still needs to be improved. SUMMARY

[0005] Based on this, the present application provides a tobacco leaf fermentation method and fermented tobacco leaf, and the contents of phenylalanine transformation products, cedrane degradation products, carotenoid degradation products and chlorophyll degradation products in the tobacco leaves subjected to fermentation treatment are significantly improved.

[0006] The specific technical solutions are as follows:

[0007] The first aspect of the present application provides a tobacco leaf fermentation method, which comprises the following steps:

[0008] The modulated cigar tobacco leaves are subjected to moisture conditioning to balance the moisture content;

[0009] The cigar tobacco leaves with balanced moisture content are mixed with sugarcane water, and after standing, an intermediate mixture is prepared;

[0010] The intermediate mixture is subjected to fermentation treatment at 35-52°C, and after re-drying, fermented tobacco leaves are prepared.

[0011] In some embodiments, the fermentation treatment comprises at least one of high-temperature fermentation, medium-temperature fermentation, and low-temperature fermentation.

[0012] Optionally, the temperature of the high-temperature fermentation is 46-52°C, the temperature of the medium-temperature fermentation is 40-44°C, and the temperature of the low-temperature fermentation is 35-38°C.

[0013] In some embodiments, the fermentation treatment comprises high-temperature fermentation, medium-temperature fermentation, and low-temperature fermentation.

[0014] In some embodiments, the humidity of the fermentation treatment is 60-90%.

[0015] Optionally, the humidity of the high-temperature fermentation is 80-90%, the humidity of the medium-temperature fermentation is 70-80%, and the humidity of the low-temperature fermentation is 60-70%.

[0016] In some embodiments, the fermentation time of the high-temperature fermentation, the medium-temperature fermentation, and the low-temperature fermentation is independently 12-30 days.

[0017] Optionally, the time ratio of the high-temperature fermentation, the medium-temperature fermentation, and the low-temperature fermentation is (1.5-2.5):1:1.

[0018] In some embodiments, the re-dried cigar tobacco leaves are subjected to re-humidification, and the water content of the re-humidified cigar tobacco leaves is 20-30%.

[0019] In some embodiments, the step of preparing the intermediate mixture comprises: spraying 4-8 wt% of cane water on the equilibrium moisture cigar tobacco leaves based on the mass of the equilibrium moisture cigar tobacco leaves, and standing for 8-12 hours; and then spraying 4-8 wt% of cane water, and standing for 8-12 hours, to prepare the intermediate mixture.

[0020] Optionally, the temperature of the re-drying is 40-45°C, and the time of the re-drying is 12-24 hours.

[0021] In some embodiments, the step of preparing the re-dried cigar tobacco leaves comprises: placing the harvested cigar tobacco leaves in an environment with a temperature of 28-32°C and a humidity of 80-90% for curing, and the curing time is 48-60 days.

[0022] In some embodiments, the method for preparing the sugar cane water comprises using a stone mill, a wooden pressing tool or a juicer to extract sugar cane juice from sugar cane as raw material.

[0023] The second aspect of the present application provides a fermented tobacco leaf prepared by the above-mentioned tobacco leaf fermentation method.

[0024] In the tobacco leaf fermentation method, the cured cigar tobacco leaf is first rehydrated to balance the moisture content; then the cigar tobacco leaf with balanced moisture content is mixed with sugar cane water to prepare an intermediate mixture after standing; and then the intermediate mixture is subjected to fermentation treatment at 35-52°C, and after re-drying, a fermented tobacco leaf is prepared. The addition of sugar cane water to the cigar tobacco leaf for flavoring and quality improvement fermentation, and under a specific fermentation process, improves the problems of existing cigar tobacco, such as strong irritation, not clean aftertaste, and oral residue, so that the content of aroma components such as alcohols, aldehydes and ketones, esters, alkanes, and aromatic compounds in the cigar tobacco leaf is significantly increased, and the quality of the cigar tobacco leaf is improved. BRIEF DESCRIPTION OF DRAWINGS

[0025] Fig. 1 The results of the content of phenylalanine conversion products, cembrane degradation products, carotenoid degradation products, and chlorophyll degradation products in the cigar tobacco leaf of each example and comparative example are shown in the following figures;

[0026] Fig. 2 The results of the content of total sugar, reducing sugar, nicotine, total nitrogen, chlorine, and potassium in the cigar tobacco leaf of each example and comparative example are shown in the following figures;

[0027] Fig. 3 The sensory quality evaluation results of the cigar tobacco leaf of each example and comparative example are shown in the following table. DETAILED DESCRIPTION

[0028] In order to facilitate the understanding of the present application, the present application will be described more fully below. However, the present application can be implemented in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0030] The prior art has qualitatively and quantitatively measured 28 kinds of aroma substances of tobacco such as cigars, which are classified as follows: phenylalanine conversion products: mainly including benzaldehyde, phenethyl alcohol, benzyl alcohol, phenylacetaldehyde, etc. These substances usually have rich aromatic odor, and can add unique floral and fruity aroma to cigars. For example, phenethyl alcohol has a soft rose fragrance, and benzaldehyde has a bitter almond flavor. Brown reaction products: mainly including furfural, furfuryl alcohol and 5-methyl furfural, etc. During the formation process, these substances can make cigars produce caramel and roasted aroma, enriching the flavor levels of cigars, such as furfural which has a flavor similar to almond and toasted bread. Degradation products of cembranoids: among them, solanone is the main representative substance. Solanone has a unique aroma and makes an important contribution to the overall aroma of cigars, and is one of the key components of cigar aroma, which can give cigars a special flavor. Its specific aroma description is relatively complex and difficult to simply compare with other common odors. Degradation products of carotenoids: including farnesyl acetone, beta-ionone, 3-hydroxy-beta dihydrodamascenone, beta-damascenone and megastigmatrienone, etc. These substances can bring a variety of aromas, such as beta-ionone with violet flower fragrance, beta-damascenone with rose and apple aroma, and megastigmatrienone with unique tobacco and spicy aroma. Degradation products of chlorophyll: mainly neophytadiene, which also plays a certain role in the aroma of cigars, and its specific aroma characteristics are difficult to describe accurately, but it helps the overall harmony of cigar aroma, and can make other aroma components better integrated together. Other categories: In addition to the above several main aroma substances, some other ingredients also have an impact on the aroma of cigars, such as some esters, alcohols, organic acids, etc. They each have different aroma characteristics, and together constitute the complex and diverse aroma system of cigars.

[0031] Sugarcane water is a traditional stone mill squeezing, wood pressing tool or modern electric juicer to extract sugarcane juice. In the process of squeezing, the cells of sugarcane are destroyed, and the juice is squeezed out. The stem of sugarcane contains a large number of parenchyma cells, which have large vacuoles and can store water. At the same time, sugarcane carries out photosynthesis to convert carbon dioxide and water into organic matter (mainly sucrose), which is accumulated in the vacuoles of the cells. In this way, water and sugar together constitute the internal juice of sugarcane, which is the main component of sugarcane water. In addition, sugarcane water is rich in vitamins and minerals, and some microorganisms such as lactic acid bacteria and yeast produce some flavor substances, adding unique aroma and taste to sugarcane water.

[0032] Based on this, an embodiment of the present application provides a tobacco leaf fermentation method, comprising steps S100-S300.

[0033] Step S100: The modulated cigar tobacco leaves are rehydrated to balance the moisture.

[0034] Step S200: mixing the balanced moisture cigar leaf with cane water, and preparing an intermediate mixture after standing.

[0035] Step S300: fermenting the intermediate mixture at 35-52°C, and preparing fermented leaf after redrying.

[0036] In the method, the modulated cigar leaf is first rehydrated to balance moisture, then mixed with cane water to prepare an intermediate mixture after standing, and then fermented at 35-52°C, and fermented leaf is prepared after redrying. The addition of cane water improves the fermentation of cigar leaf, and under the specific fermentation process, the problems of strong irritation, unclean aftertaste, and residual in the mouth of the existing cigar are improved, so that the content of aroma components such as alcohols, aldehydes and ketones, esters, alkanes, and aromatic compounds in the cigar leaf is significantly increased, and the quality of the cigar leaf is improved.

[0037] It should be noted that the temperature of the fermentation process is in the range of 35-52°C, that is, the minimum and maximum values in the range of 35-52°C, and every value between the minimum and maximum values. Specific examples include but are not limited to the following point values in the embodiments: 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, 51°C, or 52°C, or a range formed by any two of these values, for example, 35-50°C.

[0038] In some embodiments, the fermentation process includes at least one of high-temperature fermentation, medium-temperature fermentation, and low-temperature fermentation.

[0039] Further, the temperature of the high-temperature fermentation is 46-52°C, for example, it can be 46°C, 47°C, 48°C, 49°C, 50°C, 51°C, or 52°C; the temperature of the medium-temperature fermentation is 40-44°C, for example, it can be 40°C, 41°C, 42°C, 43°C, or 44°C; and the temperature of the low-temperature fermentation is 35-38°C, for example, it can be 35°C, 36°C, 37°C, or 38°C, and in some examples, it can be in a range formed by any two of these point values as end values.

[0040] In a specific example, the temperature of the high-temperature fermentation is 50°C, the temperature of the medium-temperature fermentation is 42°C, and the temperature of the low-temperature fermentation is 36°C.

[0041] In some embodiments, the fermentation process includes high-temperature fermentation, medium-temperature fermentation, and low-temperature fermentation.

[0042] The application improves the common medium added to the tobacco product by using a three-stage fermentation mode of high temperature-moderate temperature-low temperature. The first high-temperature fermentation environment is conducive to the growth and reproduction of thermophilic bacteria. For example, some bacteria of the genus Bacillus can grow in large quantities at high temperatures, and they have strong heat resistance and adaptability, can utilize fermentation substrates for metabolic activities, and produce various metabolites. These bacteria can decompose organic matter at high temperatures to provide energy and material basis for the fermentation process. In addition, bacteria of the genus Weissella, Lactobacillus and the like may also play a certain role in high-temperature fermentation. In the subsequent moderate-temperature fermentation, the moderate-temperature environment is suitable for the growth and reproduction of many molds, such as molds of the genus Aspergillus and Penicillium, which are commonly seen in moderate-temperature fermentation. These molds can secrete various enzymes to participate in the decomposition and transformation of fermentation substrates, and have an important influence on the fermentation process. For example, molds of the genus Aspergillus can secrete proteases, amylases and the like to decompose macromolecular substances such as proteins and starches into small molecules, which are convenient for other microorganisms to utilize. Under low-temperature conditions, the metabolic activity of yeast is relatively slow, and the generation speed of fermentation products is also slow. However, low-temperature fermentation can make the fermentation products have unique flavor and taste, for example, the role of yeast in some low-temperature fermented wines and fermented foods cannot be ignored.

[0043] In some embodiments, the humidity of the fermentation process described above is 60% to 90%, for example, it can be 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89% or 90%.

[0044] Further, the humidity of the high-temperature fermentation described above is 80% to 90%, for example, it can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89% or 90%; the humidity of the moderate-temperature fermentation described above is 70% to 80%, for example, it can be 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79% or 80%; the humidity of the low-temperature fermentation described above is 60% to 70%, for example, it can be 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69% or 70%.

[0045] In a specific example, the humidity of the high-temperature fermentation described above is 85%, the humidity of the moderate-temperature fermentation described above is 80%, and the humidity of the low-temperature fermentation described above is 75%.

[0046] In some embodiments, the fermentation time of the high-temperature fermentation, the medium-temperature fermentation and the low-temperature fermentation is independently 12d-30d, for example, can be 12d, 13d, 14d, 15d, 16d, 17d, 18d, 19d, 20d, 21d, 22d, 23d, 24d, 25d, 26d, 27d, 28d, 29d or 30d.

[0047] In some embodiments, the time ratio of the high-temperature fermentation, the medium-temperature fermentation and the low-temperature fermentation is (1.5-2.5):1:1, for example, can be 1.5:1:1, 1.6:1:1, 1.7:1:1, 1.8:1:1, 1.9:1:1, 2.0:1:1, 2.1:1:1, 2.2:1:1, 2.3:1:1, 2.4:1:1, 2.5:1:1.

[0048] In a specific example, the time ratio of the high-temperature fermentation, the medium-temperature fermentation and the low-temperature fermentation is 2:1:1.

[0049] The present application controls the temperature, humidity and time of the fermentation process in the above range, so that the content of aroma components such as alcohols, aldehydes and ketones, esters, alkanes and aromatics in the cigar tobacco reaches the highest value.

[0050] In some embodiments, the modulated cigar tobacco is rehydrated, and the water content of the rehydrated cigar tobacco is 20%-30%, for example, can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%.

[0051] In a specific example, the modulated cigar tobacco is rehydrated, and the water content of the rehydrated cigar tobacco is 20%.

[0052] In some embodiments, the step of preparing the intermediate mixture comprises: spraying 4wt%-8wt% of cane water on the moisture-balanced cigar tobacco based on the mass of the moisture-balanced cigar tobacco, and standing for 8h-12h; then spraying 4wt%-8wt% of cane water, and standing for 8h-12h to prepare the intermediate mixture.

[0053] In some embodiments, the re-drying temperature is 40°C-45°C, and the re-drying time is 12h-24h.

[0054] In some embodiments, the step of preparing the modulated tobacco comprises placing the harvested cigar tobacco in an environment with a temperature of 28°C-32°C and a humidity of 80%-90% for curing, and the curing time is 48d-60d.

[0055] In some embodiments, the method for preparing the cane water includes using a stone mill, a wooden pressing tool or a juicer to extract cane juice from cane.

[0056] The cane water is combined with cigar to ferment in the present application, and a three-stage fermentation mode of high temperature-moderate temperature-low temperature is adopted to promote the production of microbial metabolites and further decomposition and transformation of macromolecular substances, and to further optimize the fermentation parameters, improve the problems of existing cigar such as strong irritation, dirty aftertaste and residue in the mouth, and improve the quality of cigar leaves.

[0057] Another embodiment of the present application also provides a fermented tobacco leaf prepared by the above-mentioned tobacco leaf fermentation method.

[0058] The fermented tobacco leaf has obvious quality improvement, and the content of phenylalanine conversion products, cembrane degradation products, carotenoid degradation products and chlorophyll degradation products in the cigar leaf is significantly increased, and the content of reducing sugar, nicotine, total nitrogen, chlorine and potassium is reduced. The present application optimizes the agricultural fermentation process, so that the content of aroma components such as alcohols, aldehydes and ketones, esters, alkanes and aromatic compounds in the cigar leaf is significantly increased.

[0059] The following will be described in detail in combination with specific examples. The following examples do not include other components except for unavoidable impurities unless otherwise specified. In the examples, reagents and instruments are selected as conventional in the art unless otherwise specified. The experimental methods not specified in the examples are implemented according to conventional conditions, such as conditions described in the literature, books or recommended methods of manufacturers.

[0060] Example 1

[0061] (1) The harvested cigar leaves are placed in an environment with a temperature of 30°C and a humidity of 85% for curing, and the curing time is 60d. The cured cigar leaves are sprayed with pure water for moisture recovery, so that the water content reaches 20%, and the moisture is fully balanced in a constant temperature and humidity environment.

[0062] (2) The Fujian cane sample is placed in an electric juicer to extract Fujian cane water. The cigar leaves with fully balanced moisture are directly added with 16% unsterilized Fujian cane water, and are left to stand for 24 hours to obtain an intermediate mixture.

[0063] (3) The intermediate mixture obtained in step (2) is subjected to high-temperature primary artificial fermentation at a temperature of 50°C and a humidity of 85% in a constant temperature and humidity environment for 24d, and is subjected to 42°C re-drying for 18h to obtain cigar leaves.

[0064] Example 2

[0065] (1) The cured cigar leaves are sprayed with pure water for moisture recovery, so that the water content reaches 20%, and the moisture is fully balanced in a constant temperature and humidity environment.

[0066] (2) The fully moisture-balanced cigar leaf was directly added with 16% of non-sterilized Fujian sugarcane water and left for 24 hours to obtain an intermediate mixture.

[0067] (3) The intermediate mixture obtained in step (2) was subjected to high-temperature primary artificial fermentation for 24 days at a temperature of 50°C and a humidity of 85% in a constant temperature and humidity environment, followed by secondary fermentation for 24 days at a temperature of 42°C and a humidity of 75% in a constant temperature and humidity environment, and 18 hours of 42°C re-drying to obtain the cigar leaf. The remaining step conditions were the same as in Example 1.

[0068] Example 3

[0069] (1) The modulated cigar leaf was sprayed with pure water for re-damping to make the moisture content reach 20%, and the moisture was fully balanced in a constant temperature and humidity environment.

[0070] (2) The fully moisture-balanced cigar leaf was directly added with 16% of non-sterilized Fujian sugarcane water and left for 24 hours to obtain an intermediate mixture.

[0071] (3) The intermediate mixture obtained in step (2) was subjected to high-temperature primary artificial fermentation for 24 days at a temperature of 50°C and a humidity of 85% in a constant temperature and humidity environment, followed by secondary fermentation for 24 days at a temperature of 42°C and a humidity of 75% in a constant temperature and humidity environment, and 18 hours of 42°C re-drying to obtain the cigar leaf. The remaining step conditions were the same as in Example 1.

[0072] Example 4

[0073] (1) The modulated cigar leaf was sprayed with pure water for re-damping to make the moisture content reach 20%, and the moisture was fully balanced in a constant temperature and humidity environment.

[0074] (2) The fully moisture-balanced cigar leaf was first sprayed with 8% of non-sterilized Fujian sugarcane water and left for 12 hours, and then sprayed with 8% of non-sterilized Fujian sugarcane water and left for 12 hours to obtain an intermediate mixture.

[0075] (3) The intermediate mixture obtained in step (2) was subjected to high-temperature primary artificial fermentation for 24 days at a temperature of 50°C and a humidity of 85% in a constant temperature and humidity environment, and 18 hours of 42°C re-drying to obtain the cigar leaf. The remaining step conditions were the same as in Example 1.

[0076] Example 5

[0077] (1) The modulated cigar leaf was sprayed with pure water for re-damping to make the moisture content reach 20%, and the moisture was fully balanced in a constant temperature and humidity environment.

[0078] (2) The fully moisture-balanced cigar leaf was first sprayed with 8% non-sterilized Fujian sugarcane water and left to stand for 12 hours, and then sprayed again with 8% non-sterilized Fujian sugarcane water and left to stand for 12 hours to obtain an intermediate mixture.

[0079] (3) The intermediate mixture obtained in step (2) was subjected to high-temperature primary artificial fermentation for 24 days at a temperature of 50°C and a humidity of 85% in a constant-temperature and constant-humidity environment, and then subjected to medium-temperature primary fermentation for 24 days at a temperature of 42°C and a humidity of 75% in a constant-temperature and constant-humidity environment, and 18 hours of 42°C re-drying to obtain the cigar leaf. The remaining step conditions were the same as in Example 1.

[0080] Example 6

[0081] (1) The modulated cigar leaf was sprayed with purified water for re-damping to make the moisture content reach 20%, and the moisture was fully balanced in a constant-temperature and constant-humidity environment.

[0082] (2) The fully moisture-balanced cigar leaf was first sprayed with 8% non-sterilized Fujian sugarcane water and left to stand for 12 hours, and then sprayed again with 8% non-sterilized Fujian sugarcane water and left to stand for 12 hours to obtain an intermediate mixture.

[0083] (3) The intermediate mixture obtained in step (2) was subjected to high-temperature primary artificial fermentation for 24 days at a temperature of 50°C and a humidity of 85% in a constant-temperature and constant-humidity environment, and then subjected to medium-temperature primary fermentation for 24 days at a temperature of 42°C and a humidity of 75% in a constant-temperature and constant-humidity environment, and 18 hours of 42°C re-drying to obtain the cigar leaf. The remaining step conditions were the same as in Example 1.

[0084] Comparative Example 1

[0085] (1) The modulated cigar leaf was sprayed with purified water for re-damping to make the moisture content reach 20%, and the moisture was fully balanced in a constant-temperature and constant-humidity environment.

[0086] (2) The fully moisture-balanced cigar leaf was first sprayed with 8% non-sterilized Fujian sugarcane water and left to stand for 12 hours, and then sprayed again with 8% non-sterilized Fujian sugarcane water and left to stand for 12 hours to obtain an intermediate mixture.

[0087] (3) The intermediate mixture obtained in step (2) was subjected to high-temperature primary artificial fermentation for 24 days at a temperature of 50°C and a humidity of 85% in a constant-temperature and constant-humidity environment, and then subjected to medium-temperature primary fermentation for 24 days at a temperature of 42°C and a humidity of 75% in a constant-temperature and constant-humidity environment, and 18 hours of 42°C re-drying to obtain the cigar leaf. The remaining step conditions were the same as in Example 1.

[0088] Comparative Example 2

[0089] (1) The modulated cigar leaf was sprayed with purified water for re-damping to make the moisture content reach 20%, and the moisture was fully balanced in a constant-temperature and constant-humidity environment.

[0090] (2) The fully moisture-balanced cigar leaf was first sprayed with 8% pure water and left to stand for 12 hours, and then sprayed with 8% pure water again and left to stand for 12 hours to obtain an intermediate mixture.

[0091] (3) The intermediate mixture obtained in step (2) was subjected to high-temperature primary artificial fermentation for 24 days in a constant-temperature and constant-humidity environment at a temperature of 50°C and a humidity of 85%, and then subjected to medium-temperature primary fermentation for 24 days in a constant-temperature and constant-humidity environment at a temperature of 42°C and a humidity of 75%, and 18 hours of 42°C re-drying to obtain the cigar leaf. The remaining step conditions were the same as in Example 1.

[0092] Comparative Example 3

[0093] (1) The modulated cigar leaf was sprayed with pure water for re-damping to make the moisture content reach 20%, and the moisture was fully balanced in a constant-temperature and constant-humidity environment.

[0094] (2) The fully moisture-balanced cigar leaf was first sprayed with 8% pure water and left to stand for 12 hours, and then sprayed with 8% pure water again and left to stand for 12 hours to obtain an intermediate mixture.

[0095] (3) The intermediate mixture obtained in step (2) was subjected to high-temperature primary artificial fermentation for 24 days in a constant-temperature and constant-humidity environment at a temperature of 50°C and a humidity of 85%, and then subjected to medium-temperature primary fermentation for 24 days in a constant-temperature and constant-humidity environment at a temperature of 42°C and a humidity of 75%, and 18 hours of 42°C re-drying to obtain the cigar leaf. The remaining step conditions were the same as in Example 1.

[0096] Comparative Example 4

[0097] (1) The modulated cigar leaf was sprayed with pure water for re-damping to make the moisture content reach 20%, and the moisture was fully balanced in a constant-temperature and constant-humidity environment.

[0098] (2) The fully moisture-balanced cigar leaf was first sprayed with 8% pure water and left to stand for 12 hours, and then sprayed with 8% pure water again and left to stand for 12 hours to obtain an intermediate mixture.

[0099] (3) The intermediate mixture obtained in step (2) was subjected to high-temperature primary artificial fermentation for 24 days in a constant-temperature and constant-humidity environment at a temperature of 50°C and a humidity of 85%, and then subjected to medium-temperature primary fermentation for 24 days in a constant-temperature and constant-humidity environment at a temperature of 42°C and a humidity of 75%, and 18 hours of 42°C re-drying to obtain the cigar leaf. The remaining step conditions were the same as in Example 1.

[0100] Test: The components of the cigar leaf prepared in each example and each comparative example were detected. The sensory quality of the cigar leaf prepared in each example and each comparative example was evaluated, and the evaluation standard is shown in Table 1.

[0101] 1. The aroma substances of the cigar leaf were detected by gas chromatography-olfactometry-mass spectrometry (GC-O-MS).

[0102] 2. The determination of reducing sugar and water-soluble total sugar was performed by potassium permanganate titration; the determination of nicotine content was performed by high performance liquid chromatography (HPLC); the determination of total nitrogen content was performed by Kjeldahl method; the determination of potassium content was performed by atomic absorption spectrophotometry (AAS); and the determination of chlorine content was performed by ion chromatography (IC).

[0103] 3. The sensory evaluation of cigar tobacco leaves shall be conducted in accordance with the relevant evaluation criteria of YC / T415-2011 Sensory Evaluation Methods for Tobacco Products.

[0104] Table 1

[0105]

[0106] The specific results of component analysis of cigar tobacco prepared in each embodiment and comparative example are as follows: Figs. 1-2 As shown, the evaluation results are as follows: Fig. 3 As shown in Table 2, A1, B1, C1, D1, E1, F1, G1, H1, I1, and M represent Examples 1, 2, 3, 4, 5, 6, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, respectively. The sensory quality evaluation results of the cigar tobacco leaves prepared in each example and comparative example are shown in Table 2.

[0107] Table 2

[0108]

[0109] From the results, it can be seen that spraying sugarcane water combined with variable temperature fermentation can significantly improve the sensory quality of cigar tobacco. The aroma amount, richness, maturity, irritability, softness, delicacy, sweetness, cleanliness, aftertaste, burning, ash color, and ash density of cigar tobacco in Examples 1-6 are significantly higher than those in Comparative Examples 1-4, indicating that spraying sugarcane water is beneficial to improving the sensory quality of cigar tobacco. Among them, the treatment of spraying sugarcane water in multiple times and standing is compared with the treatment of spraying sugarcane water in one time, and the cigar tobacco has higher index values of maturity, delicacy, cleanliness, and ash color, indicating that the treatment of spraying sugarcane water in multiple times combined with variable temperature fermentation has the greatest improvement on the sensory quality of cigar tobacco. From the analysis of aroma components, after the treatment of spraying sugarcane water in multiple times combined with variable temperature fermentation, the phenylalanine conversion products, brown reaction products, cembrane degradation products, carotenoid degradation products, and chlorophyll degradation products all increase, indicating that adding sugarcane water combined with variable temperature fermentation is beneficial to the accumulation of aroma components. In addition, compared with the comparative examples, the sugar substances in cigar tobacco will significantly decrease. This may be because starch and other polysaccharides will be decomposed into monosaccharides such as glucose under the action of enzymes. This is because the enzymes such as amylase secreted by microorganisms can catalyze the hydrolysis reaction of starch. With the progress of fermentation, the content of monosaccharides will gradually increase. On the one hand, these monosaccharides can be used as carbon sources for microbial growth and be metabolized by microorganisms; on the other hand, monosaccharides will participate in the Maillard reaction in the subsequent processing and combustion process, generating compounds with roasting, caramel, and other aromas, thereby affecting the aroma of cigar tobacco. In addition, part of the reducing sugar will also react with amino acids to generate melanoidin and other substances, which also play an important role in improving the color and flavor of cigar tobacco. At the same time, the content of nicotine and other alkaloids in the examples is also relatively lower. During the fermentation process, part of the nicotine may be degraded or chemically transformed by microorganisms. This helps to adjust the strength of cigar tobacco and reduce irritability. For example, through the metabolic action of microorganisms, nicotine can be converted into other nitrogen-containing compounds, reducing its relative content in cigar tobacco, so that the smoker can enjoy the aroma of cigar tobacco while reducing the discomfort caused by high nicotine.

[0110] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not contradict each other, they should be considered within the scope of the present disclosure.

[0111] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the patent protection scope of the present application should be based on the appended claims.

Claims

1. A tobacco leaf fermentation method, characterized by, The method comprises the following steps: The modulated cigar leaves are rehydrated to balance the moisture content; The rehydrated cigar leaves are mixed with sugarcane water to prepare an intermediate mixture; The intermediate mixture is subjected to fermentation treatment at a temperature of 35-52°C to prepare fermented leaves after re-drying.

2. The tobacco leaf fermentation method of claim 1, wherein, The fermentation treatment comprises at least one of high-temperature fermentation, medium-temperature fermentation and low-temperature fermentation. Optionally, the temperature of the high-temperature fermentation is 46-52°C, the temperature of the medium-temperature fermentation is 40-44°C, and the temperature of the low-temperature fermentation is 35-38°C.

3. The tobacco leaf fermentation method of claim 2, wherein, The fermentation treatment comprises high-temperature fermentation, medium-temperature fermentation and low-temperature fermentation.

4. The tobacco leaf fermentation method of claim 3, wherein, The humidity of the fermentation treatment is 60-90%. Optionally, the humidity of the high-temperature fermentation is 80-90%, the humidity of the medium-temperature fermentation is 70-80%, and the humidity of the low-temperature fermentation is 60-70%.

5. The tobacco leaf fermentation method of claim 4, wherein, The fermentation time of the high-temperature fermentation, the medium-temperature fermentation and the low-temperature fermentation is independently 12-30 days. Optionally, the time ratio of the high-temperature fermentation, the medium-temperature fermentation and the low-temperature fermentation is (1.5-2.5):1:

1.

6. The tobacco leaf fermentation method according to any one of claims 1 to 5, wherein, The modulated cigar leaves are rehydrated to make the water content of the rehydrated cigar leaves reach 20-30%.

7. The tobacco leaf fermentation method according to any one of claims 1 to 5, wherein, The step of preparing the intermediate mixture comprises: spraying 4-8 wt% of the sugarcane water on the rehydrated cigar leaves based on the mass of the rehydrated cigar leaves, and standing for 8-12 hours; and then spraying 4-8 wt% of the sugarcane water and standing for 8-12 hours to prepare the intermediate mixture. Optionally, the temperature of the re-drying is 40-45°C, and the time of the re-drying is 12-24 hours.

8. The tobacco leaf fermentation method according to any one of claims 1 to 5, wherein, The step of preparing the modulated leaves comprises: airing the harvested cigar leaves in an environment with a temperature of 28-32°C and a humidity of 80-90% for 48-60 days.

9. The tobacco leaf fermentation method of any one of claims 1 to 5, wherein, The method for preparing the sugarcane water comprises: using a stone mill, a wooden pressing tool or a juicer to extract sugarcane juice from sugarcane.

10. A fermented tobacco leaf, characterized in that, The fermented leaves are prepared by using the method for fermenting tobacco leaves according to any one of claims 1-9.

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