Preparation method of dark tobacco leaf for cigar based on oxygen-increasing fermentation

Abstract

The application discloses a preparation method of cigar tobacco deep color jacket based on oxygen-increasing fermentation, and relates to the technical field of cigar production and processing. The method is characterized by the following steps: soaking the dried cigar tobacco in a mixed solution of ferric citrate and xylo-oligosaccharide, naturally air-drying, controlling the water content of the cigar tobacco raw material, and then performing fermentation treatment to obtain the finished product of the cigar tobacco deep color jacket. The method can effectively deepen the color of the cigar tobacco, meet the quality requirements of the jacket, and obviously improve the aroma quality and aroma amount of the jacket. When the oxygen concentration in the fermentation environment is controlled to be about 29% at the same time, the above-mentioned effects are more obvious, and the economic value of the cigar jacket product is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of cigar production and processing technology, and in particular to a method for preparing dark wrappers for cigar tobacco leaves. Background Technology

[0002] Cigar wrapper tobacco is the outermost layer of tobacco in a cigar, and its appearance quality requires extremely high standards. The depth and uniformity of the leaf color are among the most important indicators for evaluating cigar wrappers. Internationally, wrapper colors are classified into seven basic colors: bluish-brown, light brown, medium brown, dark reddish-brown, dark brown, blackish-brown, and black. Different colored wrappers are positioned differently for different products. Currently, domestically produced wrappers are generally light to medium brown, which is unsuitable for high-end cigars. Dark-colored wrapper raw materials mainly rely on international imports, and dark brown, blackish-brown, and black wrappers are often very expensive due to their complex processing steps. Therefore, improving the color uniformity and chromaticity value of cigar wrapper tobacco leaves to produce highly uniform dark wrappers has become a key research focus in current cigar wrapper production and processing technology.

[0003] Among existing cigar wrapper processing technologies, Chinese patent application CN111728260A provides a method and fermentation medium for improving the color uniformity of cigar wrapper tobacco leaves. This involves first boiling and soaking raw materials such as tobacco leaves, citrus / lemon peel, white sugar, white wine, honey, cinnamon, licorice, herbal tea, cedar wood chips, and water to obtain an extract. The extract is then used to soak the wrapper tobacco leaves, and finally fermentation is performed to obtain a dark-colored wrapper. Chinese patent application CN112515233A provides a method for preparing Maduro cigar wrappers, which involves mixing aromatic leaves / petals that enhance the wrapper's flavor with tobacco leaves, and using techniques such as low-temperature insecticidal treatment, glucose solution soaking in the stem, and rehydration fermentation to produce brown, near-black, and black Maduro cigar wrappers. Chinese patent application CN113287777A discloses a method for producing Maduro wrappers through high-temperature and high-humidity fermentation. The method involves soaking the stem ends of loosened tobacco leaves in warm water, then adding moisture to increase the leaf's moisture content. After sealing and balancing, the leaves are soaked in warm water again to remove surface water, balancing once more, and finally flattened for high-temperature and high-humidity fermentation at 55-65℃ and 70-85% humidity to obtain Maduro wrappers. Chinese patent application CN111053284A discloses a method for accelerating tobacco aging. This method involves sealing tobacco stacks with a sealing film, introducing oxygen or ozone, maintaining a relative humidity of 55-70%, and a temperature of 15-35℃. Adjusting the aging conditions within the sealed film effectively shortens the aging time to 3-12 months, resulting in cigar tobacco leaves free from pests and mold, with no darkening of color and enhanced aroma. Chinese patent application CN114557474A discloses a method for storing and aging cigar tobacco raw materials. First, the cigar tobacco leaves are sterilized, packed / stacked, and maintained at a temperature of 25-30℃, humidity of 65-75%, and oxygen content of 20%-21% for aging for 4-13 months. Then, the temperature is maintained at 21-27℃, humidity of 65-70%, and oxygen content below 2%, with a shelf life of 3-12 months. Finally, the cigar tobacco leaves are removed and stacked for fermentation for 35-40 days. Ultimately, the quality of the tobacco leaves is improved by evaluating indicators such as aroma quality, aroma intensity, off-flavors, irritation, aftertaste, sweetness, combustibility, and ash color. Chinese authorized patent CN113331456B discloses a method for kneading and making Maduro wrappers. After balancing and removing stems from tobacco leaves with a moisture content of 25-35%, the leaves are soaked in water and kneaded to obtain cigar tobacco leaves with a deep and uniform color, high oil content, and good overall oiliness. Chinese patent CN105795506B discloses a fermentation method for improving the quality and reducing the consumption of cigar tobacco. The method involves balancing cigar tobacco leaves with a moisture content of 22-26%, fermenting them for 12-15 days at a temperature of 25-30℃ and a relative humidity of 75-78%. The treated tobacco leaves are then sealed and filled with nitrogen to maintain an oxygen concentration of 8-10%, kept at 25-30℃ for 30-35 days. Finally, the leaves are ventilated and dehumidified until the moisture content reaches below 17%, resulting in cigar tobacco leaves with low dry matter consumption, uniform color, good softness, good elasticity, and strong tensile strength.

[0004] The technologies used in the aforementioned existing technologies are either not designed for processing dark-colored tobacco leaves; or the processes are complex, cumbersome, and the cost of other raw materials is too high; or there are problems such as poor uniformity of color and insufficient color depth in the tobacco leaves. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a highly uniform dark-colored tobacco wrapper preparation method based on aerobic fermentation technology. This method not only simplifies and facilitates the production process but also produces dark-colored tobacco leaves with uniform color, high aroma quality and quantity, and strong industrial applicability. Specifically, this is achieved through the following technologies.

[0006] A method for preparing dark wrapper for cigar tobacco leaves based on aerobic fermentation includes the following steps:

[0007] S1. Select dried cigar tobacco leaves and (add water) prepare a mixture of ferric citrate and xylooligosaccharides; the mass ratio of ferric citrate to xylooligosaccharides is 1:1.

[0008] S2. Soak the cigar tobacco leaves in the mixture for 3-5 minutes, then remove the cigar tobacco leaves and air dry them until no mixture residue remains.

[0009] S3. Control the moisture content of the cigar tobacco raw material obtained in step S2, and carry out fermentation treatment to obtain the dark-colored cigar wrapper product.

[0010] The method for preparing dark cigar wrappers provided by this invention is based on existing common or traditional methods for preparing cigar wrappers. The method involves first soaking cigar tobacco raw materials that meet the requirements for wrappers in a mixture of ferric citrate and xylooligosaccharides (hereinafter referred to as the mixture), then air-drying them before proceeding with other conventional fermentation processes. After soaking in the mixture, the brightness and color values ​​of the cigar tobacco leaves obtained after fermentation are significantly different from those before fermentation. That is, the color of the cigar tobacco leaves is significantly darker after fermentation, and the color distribution is very uniform. Compared with cigar tobacco leaves that have not been soaked in the mixture, the cigar tobacco leaves soaked in the mixture are darker in color, have higher quality and more uniform color, and also have higher aroma quality and aroma intensity.

[0011] Preferably, in step S1, the total concentration of ferric citrate and xylooligosaccharides in the mixture is 0.5-2.0%. When the total concentration of ferric citrate and xylooligosaccharides is too low, the color of the cigar wrapper will not deepen sufficiently; when it is higher than 2.0%, the improvement is not obvious and raw materials are wasted.

[0012] More preferably, in step S1, the total concentration of ferric citrate and xylooligosaccharides in the mixture is 2.0%.

[0013] After a large number of experimental tests, it is found that when the total concentration of ferric citrate and xylo-oligosaccharide is 2.0%, the brightness value and the chroma value of the fermented cigar leaf decrease the most, that is, the color of the cigar leaf wrapper is darker, which meets the quality requirements of the cigar leaf wrapper.

[0014] Preferably, in step S3, the water content of the cigar leaf raw material is 28-30%.

[0015] More preferably, in step S3, the water content of the cigar leaf raw material is 29%.

[0016] At present, there is no specific and strict requirement for the water content of the cigar leaf before fermentation in the fermentation process of the cigar leaf wrapper on the market, which is generally 22-30%, and the highest can reach 35% or even 40%. After a large number of experimental tests, it is found that no matter the water content of the cigar leaf raw material is within the above range, as long as the water content remains unchanged, after soaking with the above mixed solution, the cigar leaf wrapper obtained by fermentation can make the brightness value and the chroma value of the cigar leaf decrease significantly. This also shows that the soaking with the mixed solution has a positive effect on the color index of the finished cigar leaf wrapper.

[0017] Preferably, in step S3, when the center temperature of the cigar leaf pile is higher than 50℃ or the temperature continuously decreases for 24h, immediately perform the turning pile treatment, and the specific method is: shake and cool the leaf to room temperature and then perform fermentation again, the relative humidity of the environment air is not less than 75%, and the time for shaking the leaf is 0.5-1.0h. The turning pile treatment is a common treatment step for the fermentation of the cigar leaf, and the purpose is to prevent the temperature of the leaf from being too high during the fermentation, so as to affect the fermentation effect and the quality of the leaf.

[0018] More preferably, in step S3, during the fermentation treatment, the oxygen concentration in the fermentation environment is also controlled to be 28-30%, and the turning pile treatment is also performed during the fermentation, until the center temperature of the cigar leaf pile in the fermentation chamber no longer changes or the change amplitude is not more than 1℃, and then the fermentation is completed. The applicant found through further research that when the above mixed solution is used to soak the cigar leaf raw material and the oxygen concentration in the fermentation chamber is controlled to be 28-30% during the fermentation, it is beneficial to the oxidation of the leaf and ultimately makes the color of the cigar leaf wrapper uniform and darker. When the oxygen concentration is lower than 28%, the oxidation speed is slow, and the color deepening is not enough in a short time; when the oxygen concentration is higher than 30%, the leaf is oxidized violently and the color is rapidly deepened, which is not uniform and is difficult to control the reaction, affecting the quality stability of the leaf wrapper. This shows that when the above special mixed solution is used for soaking and the oxygen concentration in the fermentation environment is controlled within a specific range, the cigar leaf wrapper with the most required color index can be prepared.

[0019] Further preferably, in step S3, the oxygen concentration in the fermentation environment is 30%. When the oxygen concentration in the fermentation environment is 30%, the soaking step of the mixed solution can make the color of the cigar wrapper the deepest.

[0020] Compared with the prior art, the present application has the advantages that: the present application provides a preparation method of deep color cigar wrapper. By using the mixed solution of ferric citrate and xylo-oligosaccharide to soak the cigar wrapper raw materials before fermentation, the color of the finished product of the cigar wrapper is significantly deepened; and when the oxygen concentration around is increased to 28-30% during fermentation, the color deepening effect is more obvious. The whole method is simple to operate and does not require too much additional labor cost, and the color quality of the finished product of the cigar wrapper is higher and more uniform; the aroma quality and amount of the wrapper are also significantly improved. DETAILED DESCRIPTION

[0021] The technical solutions of the present application will be described below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0022] The following examples and comparative examples provide a preparation method of deep color cigar wrapper, which is prepared by the following method if not specified:

[0023] S1, according to the basic requirements of cigar wrapper, 120 kg of CX26 wrapper variety from Danjiangkou City, Hubei Province was selected as the raw material for making deep color cigar wrapper, the length of the tobacco leaf was 40-50 cm, and the thickness was 0.05-0.10 mm;

[0024] The same amount of ferric citrate (Renyou Chemical Co., Ltd., AR 500 g) and xylo-oligosaccharide (Shandong Longli Biological Technology Co., Ltd., food grade, 500 g) were prepared into a mixed solution with a specific total concentration, and were prepared for use;

[0025] S2, all the tobacco leaves were soaked in the mixed solution for 3 minutes, and then the soaked raw materials were taken out; the tobacco leaves drained of the mixed solution were placed on a 20-mesh screen on a 30° inclined plane and naturally air-dried for 1.5 h until no obvious mixed solution flowed out or remained on the surface of the tobacco leaves;

[0026] S3, an oxygen cylinder and an oxygen concentration monitoring device were placed in the fermentation chamber to control the oxygen concentration in the fermentation chamber; the moisture content of the tobacco leaves was measured before humidification, the amount of water to be added was calculated according to the target moisture value, and then the tobacco leaves were humidified by spraying;

[0027] The fermentation wood box with a size of 120x80x80cm is used, and cotton cloth is laid on the bottom and around the box; the humidified tobacco leaves are laid flat in the fermentation box with the leaf stalks outward and the leaf tips inward; when the tobacco leaves are laid to the level of the box mouth, the cotton cloth is covered and the cover plate is covered, and a weight of 25kg is used for fermentation;

[0028] A temperature probe is placed at the center of the cigar tobacco pile in the fermentation box, and the temperature of the fermentation box is observed and recorded every 2h; when the center temperature of the cigar tobacco pile is detected to be ≥50℃, or the temperature continuously decreases for 24h, the box is immediately opened and the pile is turned over; when the pile is turned over, all the tobacco leaves are fully shaken and scattered, so that they are completely cooled to room temperature, and then the tobacco leaves are re-packed for continuous fermentation; the turning over process is carried out in a room with a relative humidity of ≥75%, and the time for shaking and scattering the tobacco leaves is controlled to be 0.5-1.0h, so as to prevent excessive loss of moisture in the tobacco leaves and affect the subsequent fermentation effect.

[0029] In the above method, the oxygen concentration is controlled by observing the oxygen concentration of the oxygen monitoring equipment at 8am every day, and the oxygen concentration in the fermentation chamber is adjusted manually when the oxygen concentration is insufficient.

[0030] When the center temperature of the cigar tobacco pile in the fermentation box approaches the ambient temperature, or the change range of the center temperature of the cigar tobacco pile in the fermentation box is <1℃ for 4 consecutive days, the fermentation is completed.

[0031] Example 1

[0032] The preparation method of the cigar tobacco leaf dark wrapper provided in this embodiment is based on the above preparation method, and the total concentration of the mixed solution in step S1 is set to 1.0%; in step S3, the oxygen concentration in the fermentation chamber is continuously controlled to be (29±1) %.

[0033] Example 2

[0034] The preparation method of the cigar tobacco leaf dark wrapper provided in this embodiment is based on the above preparation method, and the total concentration of the mixed solution in step S1 is set to 1.0%; in step S3, the oxygen concentration in the fermentation chamber is continuously controlled to be (29±1) %.

[0035] Example 3

[0036] The preparation method of the cigar tobacco leaf dark wrapper provided in this embodiment is based on the preparation method of Example 2, and the total concentration of the mixed solution in step S1 is set to 0.2%; in step S3, the oxygen concentration in the fermentation chamber is continuously controlled to be (29±1) %.

[0037] Example 4

[0038] The method for preparing dark cigar wrapper provided in this embodiment is based on the preparation method of Example 2, except that the total concentration of the mixture in step S1 is set to 0.5%; and in step S3, the oxygen concentration in the fermentation chamber is continuously controlled at (29±1)%.

[0039] Example 5

[0040] The method for preparing dark cigar wrapper provided in this embodiment is based on the preparation method of Example 2, except that the total concentration of the mixture in step S1 is set to 2.0%; and in step S3, the oxygen concentration in the fermentation chamber is continuously controlled at (29±1)%.

[0041] Example 6

[0042] The method for preparing dark cigar wrapper provided in this embodiment is based on the preparation method in Example 2, except that the total concentration of the mixture in step S1 is set to 3.0%; in step S3, the fermentation chamber is in a normal air environment and is kept under normal ventilation, without any oxygen concentration control or monitoring.

[0043] Comparative Example 1

[0044] In the method for preparing dark cigar wrapper provided in this comparative example, the same cigar wrapper raw materials as those in other embodiments are selected in accordance with the basic requirements of cigar wrapper; the moisture content of the cigar wrapper raw materials is controlled to be 29% by weighing and humidifying (measuring the moisture content of the tobacco leaves before humidification, calculating the amount of water to be added according to the target moisture value, and then humidifying by spraying).

[0045] The tobacco leaves were stacked and fermented using the same fermentation boxes and methods as in other embodiments, and the entire fermentation chamber was normally ventilated without any oxygen concentration control. The temperature inside and outside the fermentation chamber was monitored, and the turning process inside the fermentation chamber was the same as in other embodiments.

[0046] Comparative Example 2

[0047] In the method for preparing dark cigar wrapper provided in this comparative example, the same cigar wrapper raw materials as those in other embodiments are selected in accordance with the basic requirements of cigar wrapper; the moisture content of the cigar wrapper raw materials is controlled to be 29% by weighing and humidifying (measuring the moisture content of the tobacco leaves before humidification, calculating the amount of water to be added according to the target moisture value, and then humidifying by spraying).

[0048] The tobacco leaves were stacked and fermented using the same fermentation boxes and fermentation methods as in other embodiments; and the oxygen concentration in the entire fermentation chamber was controlled at (29±1)%. The temperature inside and outside the fermentation box was monitored, and the turning process inside the fermentation box was the same as in other embodiments.

[0049] Comparative Example 3

[0050] The preparation method of the dark tobacco wrapper for cigar provided in the comparative example is the same as that in Example 2 for steps S2 and S3, and the mixed solution used in step S1 is an aqueous solution of iron citrate with a concentration of 1.0%.

[0051] Comparative Example 4

[0052] The preparation method of the dark tobacco wrapper for cigar provided in the comparative example is the same as that in Example 2 for steps S2 and S3, and the mixed solution used in step S1 is an aqueous solution of xylo-oligosaccharide with a concentration of 1.0%.

[0053] Comparative Example 5

[0054] The preparation method of the dark tobacco wrapper for cigar provided in the comparative example is the same as that in Example 3 for steps S2 and S3, and the mixed solution used in step S1 is an aqueous solution of equal mass of baijiu (45°) and honey, with a total concentration of 1.0%, instead of the original mixed solution of iron citrate and xylo-oligosaccharide.

[0055] Test Example 1: Brightness value and color change of cigar tobacco leaves after fermentation according to the above examples and comparative examples

[0056] The cigar tobacco leaves after fermentation according to the above examples and comparative examples were shaken and classified according to the YC / T 588-2021 Cigar Tobacco Leaf Industrial and Commercial Handover Grade Standard to obtain dark tobacco leaves with uniform color, and the proportion of dark tobacco leaves with uniform color in all tobacco leaves was calculated.

[0057] The color difference value of the cigar tobacco leaves before and after fermentation was measured using a CIE X precision color difference meter, the color difference meter was calibrated with a standard black cavity, and after calibration, the standard white plate was used for full white calibration; after calibration, the sample value was saved; then the brightness value L*, red-green value a*, and yellow-blue value b* of the cigar tobacco leaves were measured. The color calculation formula is as follows:

[0058]

[0059] In the formula, L*0, a*0, and b*0 represent the color parameters of the standard white plate (L*0 = 94.59, a*0 = 0.01, and b*0 = 1.04). The larger the E value, the darker the color of the measured sample. The difference between the E value after fermentation and the E value before fermentation, i.e. ΔE, and the difference between the L value after fermentation and the L value before fermentation, i.e. ΔL, were calculated. The larger the absolute value of ΔL and ΔE (negative value), the greater the difference in brightness value and color value between the cigar tobacco leaves before and after fermentation, and the better the color deepening effect of fermentation on the cigar tobacco leaves.

[0060] The color change of the cigar leaf of Comparative Example 1 is shown in Table 1 below, the color change of the cigar wrapper obtained by the method of Example 1 is shown in Table 2 below, the color change of the cigar wrapper obtained by the method of Example 2 is shown in Table 3 below, the color change of the cigar wrapper obtained by the method of Example 3 is shown in Table 4 below, the color change of the cigar wrapper obtained by the method of Example 4 is shown in Table 5 below, the color change of the cigar wrapper obtained by the method of Example 5 is shown in Table 6 below, the color change of the cigar wrapper obtained by the method of Example 6 is shown in Table 7 below, the color change of the cigar wrapper obtained by the method of Comparative Example 1 is shown in Table 8 below, the color change of the cigar wrapper obtained by the method of Comparative Example 2 is shown in Table 9 below, the color change of the cigar wrapper obtained by the method of Comparative Example 3 is shown in Table 10 below, the color change of the cigar wrapper obtained by the method of Comparative Example 4 is shown in Table 11 below, and the color change of the cigar wrapper obtained by the method of Comparative Example 5 is shown in Table 12 below.

[0061] Table 1 Color change of the treated cigar leaf of Comparative Example 1

[0062]

[0063] As can be seen from Table 1 above, the average value of ΔL is -3.94 and the average value of ΔE is 0.60.

[0064] Table 2 Color change of the cigar wrapper obtained by the method of Example 1

[0065]

[0066] As can be seen from Table 2 above, when 1.0% of the mixed solution of ferric citrate and xylo-oligosaccharide is added without controlling the oxygen concentration in the fermentation chamber, the average value of ΔL is -4.20 and the average value of ΔE is 1.08, which indicates that the difference in brightness of the treated cigar leaf is reduced by 0.26 and the color difference is increased by 0.48 compared with the water treatment, indicating that the fermentation treatment with 1.0% of the mixed solution of ferric citrate and xylo-oligosaccharide can increase the color of the treated cigar leaf.

[0067] Table 3 Color change of the cigar wrapper obtained by the method of Example 2

[0068]

[0069] As can be seen from Table 3 above, when 1.0% of the mixed solution of ferric citrate and xylo-oligosaccharide is added and the oxygen concentration in the fermentation chamber is controlled, the average value of ΔL is -8.81 and the average value of ΔE is 6.84, which indicates that the brightness of the treated cigar leaf is significantly reduced and the color is significantly deepened compared with Example 1.

[0070] Table 4 Color change of cigar wrapper obtained by the method of Example 3

[0071]

[0072] As can be seen in Table 4 above, after the addition of 0.2% of the mixture of ferric citrate and xylo-oligosaccharide and control of the oxygen concentration in the fermentation chamber, the average AL was -8.35 and the average AE was 1.52, which was 4.41 lower than the brightness value and 0.93 lower than the color difference value of Comparative Example 1 (treated with water), indicating that the color of the cigar tobacco leaves treated with the mixture and controlled oxygen concentration was significantly deepened.

[0073] Table 5 Color change of cigar wrapper obtained by the method of Example 4

[0074]

[0075] As can be seen in Table 5 above, after the addition of 0.5% of the mixture of ferric citrate and xylo-oligosaccharide and control of the oxygen concentration in the fermentation chamber, the average AL was -11.61 and the average AE was 4.96, which was 4.41 lower than the brightness value and 0.93 lower than the color difference value of Comparative Example 1 (treated with water), indicating that the brightness value of the cigar tobacco leaves treated with the mixture was significantly reduced and the color was significantly deepened.

[0076] Table 6 Color change of cigar wrapper obtained by the method of Example 5

[0077]

[0078] As can be seen in Table 6 above, after the addition of 2.0% of the mixture of ferric citrate and xylo-oligosaccharide and control of the oxygen concentration in the fermentation chamber, the average AL was -10.29 and the average AE was 3.46, indicating that the brightness value of the cigar tobacco leaves treated with the mixture was significantly reduced and the color was significantly deepened.

[0079] Table 7 Color change of cigar wrapper obtained by the method of Example 6

[0080]

[0081] As can be seen in Table 7 above, after the addition of 3.0% of the mixture of ferric citrate and xylo-oligosaccharide and control of the oxygen concentration in the fermentation chamber, the average AL was -6.16 and the average AE was 1.62, indicating that the brightness value of the cigar tobacco leaves treated with the mixture was reduced and the color was deepened, but compared with the brightness value reduction and color deepening of the cigar tobacco leaves of Example 2, Example 4 and Example 5, in which the oxygen concentration in the fermentation chamber was controlled to be continuously (29±1)%, the brightness value reduction and color deepening of the cigar tobacco leaves of Example 6 was obvious.

[0082] Color change of the cigar wrapper obtained by the method of Example 1

[0083]

[0084]

[0085] As can be seen in Table 8 above, the comparative example 1 did not use any soaking solution for the cigar wrapper raw material and did not control the oxygen concentration during fermentation, with an average of -3.94 for AL and 0.59 for AE, indicating that conventional fermentation treatment can also increase the color of the cigar wrapper to a certain extent, but the degree is low.

[0086] Color change of the cigar wrapper obtained by the method of Example 2

[0087]

[0088] As can be seen in Table 9 above, the comparative example 2 did not use any soaking solution for the cigar wrapper raw material and controlled the oxygen concentration in the fermentation chamber to be (29±1)%, with an average of -5.14 for AL and 1.54 for AE, indicating that controlling the oxygen concentration to be (29±1)% after fermentation, the brightness value of the cigar wrapper color decreased by -1.20 and the color difference value decreased by 0.95, indicating that controlling the oxygen concentration to be (29±1)% has the effect of deepening the color of the cigar wrapper after fermentation.

[0089] Color change of the cigar wrapper obtained by the method of Example 3

[0090]

[0091] As can be seen in Table 10 above, the comparative example 3 used only 1.0% lemon iron solution for soaking the cigar wrapper raw material and controlled the oxygen concentration in the fermentation chamber to be (29±1)%, with an average of -7.80 for AL and 2.38 for AE, indicating that the brightness value of the cigar wrapper color after fermentation decreased by -2.66 and the color difference value decreased by 0.84 compared with the comparative example 2, indicating that under the condition of oxygen concentration of (29±1)% in the fermentation chamber, using lemon iron solution for soaking has the effect of deepening the color of the cigar wrapper after fermentation.

[0092] Color change of the cigar wrapper obtained by the method of Example 4

[0093]

[0094] As can be seen from Table 11, in the case of Comparative Example 4, the solution of 1.0% xylo-oligosaccharide in water was used to soak the raw material of cigar wrapper, and the oxygen concentration in the fermentation chamber was controlled to be (29±1)%, the average △L was -7.59, and the average △E was 2.12. Compared with Comparative Example 2, the color brightness value of the cigar leaf after fermentation was reduced by -2.45, and the color difference value was reduced by 0.58. This indicates that under the condition of an oxygen concentration of (29±1)% in the fermentation chamber, the use of xylo-oligosaccharide solution for soaking has the effect of deepening the color of the cigar leaf after fermentation.

[0095] Table 12: Color change of cigar wrapper obtained by the method of Comparative Example 5

[0096]

[0097] As can be seen from Table 12, in the case of Comparative Example 5, the solution of 1.0% conventional white wine and honey was used to soak the raw material of cigar wrapper, and the oxygen concentration in the fermentation chamber was controlled to be (29±1)%, the average △L was -5.16, and the average △E was 1.61. Compared with Comparative Example 2, the color brightness value of the cigar leaf after fermentation was reduced by -0.02, and the color difference value was reduced by 0.10. This indicates that under the condition of an oxygen concentration of (29±1)% in the fermentation chamber, the use of white wine and honey solution for soaking has the effect of deepening the color of the cigar leaf after fermentation, which is similar to the effect of water, and is worse than the effects of iron citrate or xylo-oligosaccharide.

[0098] In summary, for the soaking with the mixed solution of iron citrate and xylo-oligosaccharide (operation ①) and the control of the oxygen concentration in the fermentation chamber to be (29±1)% (operation ②):

[0099] When operation ① is used alone, it can be seen from the comparison with the control group of clean water that the brightness value of the treated tobacco leaf is significantly reduced, and the color is significantly deepened.

[0100] When operations ① and ② are used simultaneously, the degree of brightness value reduction and color deepening of the treated tobacco leaf is greater than when operation ① is used alone.

[0101] When operations ① and ② are used simultaneously, and only the concentration of the mixed solution is changed, the greater the concentration of the mixed solution, the greater the degree of brightness value reduction and color deepening of the tobacco leaf.

[0102] When operations ① and ② are not performed on the raw material of cigar wrapper, the brightness value change of the tobacco leaf treated by fermentation with water without controlling the oxygen concentration is small.

[0103] When operation ② is used alone, although the brightness value of the treated tobacco leaf is reduced to a certain extent, and the color is deepened to a certain extent, it is far from the effect of using operation ① alone and using operations ① and ② simultaneously.

[0104] When operation ① is used alone and the mixed solution only contains ferric citrate or xylo-oligosaccharide, although the brightness value of the treated tobacco leaves is reduced to a certain extent and the color is deepened to a certain degree, the effect is not as good as that of using operation ① alone and using operations ① and ② simultaneously.

[0105] When operations ① and ② are used simultaneously and the mixed solution is replaced by a mixed aqueous solution of white spirit and honey, the degree of reduction in brightness value and deepening of color of the tobacco leaves is also not as good as that of using operation ① alone and using operations ① and ② simultaneously.

[0106] Test Example 2: Quality evaluation of cigar tobacco leaves after fermentation of the above examples and comparative examples

[0107] Cigar tobacco sensory quality evaluation method: After the fermentation of the cigar tobacco sample is completed, 1.0-2.0 kg of the sample is selected, and 30 standard cigar samples are rolled according to the method specified in GBT 15269.1-2010 "Cigar Tobacco Part 1: Product Classification and Sampling Technical Requirements". The standard cigar samples obtained have a medium size, a weight of 3.0-6.0 g per sample, a length of 13-15 cm, a diameter of 1.6-1.7 cm, and a proper tightness.

[0108] Five to seven professional evaluators are invited to evaluate the sensory quality of the standard cigar samples, and the number of standard cigar samples is selected according to the number of evaluators. The evaluation criteria for the sensory quality of the standard cigar samples include aroma quality, aroma quantity, odor, irritation, aftertaste, sweetness, burning property, and ash color. The specific evaluation method is referred to the evaluation method specified in GB 15269.4-2011 "Cigar Tobacco Part 4: Sensory Technical Requirements". Each index is scored according to the scoring standard in Table 13, and the score of each index is averaged according to the number of evaluators. The total score of the sensory evaluation quality of the cigar is obtained by adding the average scores of each index.

[0109] Table 13: Scoring standard for cigar tobacco sensory quality evaluation indexes

[0110] No. Evaluation index Scoring standard 1 Quality of aroma Good: 18-16; moderate: 15-13; poor: ≤12. 2 Amount of aroma Enough: 16-14; general: 13-11; weaker: ≤10. 3 Odor None: 10-9; lighter: 8-7; have: 6-5; heavy: ≤4. 4 Irritation None: 12-11; slightly: 10-9; have: 8-7; larger: ≤6. 5 Aftertaste Comfortable: 16-14; more comfortable: 13-11; still comfortable: 10-8; slightly bitter, tongue: ≤7. 6 Sweetness Strong: 10-9; moderate: 8-7; weaker: 6-5; weak: ≤4. 7 Combustion Good: 10-8; moderate: 7-5; poor: 4-2; extinguish: ≤1. 8 Ash color Ash white: 8-7; gray: 6-5; gray black: 4-3; black: ≤2.

[0111] The total score of the eight evaluation indexes in Table 13 is 100 points, and the score is recorded in units of 0.5 points.

[0112] The artificial evaluation scores of the burning property and sensory evaluation quality of the cigar tobacco samples are shown in Table 14. The sensory evaluation quality scoring levels are as follows: <50 points for poor, 50-60 points for relatively poor, 60-70 points for general, 70-80 points for relatively good, and >80 points for good.

[0113] Table 14: Artificial evaluation scores of some examples and comparative examples

[0114]

[0115] From the evaluation results of Table 14, it can be seen that the method of the present application can also improve the sensory quality of the finished cigar wrapper to a certain extent, and has higher economic value. Among them, the effect is better when the cigar wrapper raw material is soaked in the mixed solution of the present application and the oxygen concentration in the environment during fermentation is controlled.

[0116] In summary, the method of the present application not only can make the color of the finished cigar wrapper significantly deeper, the color quality higher, and the color more uniform, but also can significantly improve the aroma quality and aroma amount of the wrapper.

[0117] The above specific embodiments describe the implementation of the present application in detail, but the present application is not limited to the specific details in the above embodiments. Within the scope of the claims and technical concepts of the present application, various simple modifications and changes can be made to the technical solutions of the present application, and these simple modifications all belong to the protection scope of the present application.

Claims

1. A process for the preparation of dark wrapper for cigar tobacco based on oxygen-boosted fermentation, characterized in that, The method comprises the following steps: S1, selecting air-dried cigar tobacco leaves, and preparing a mixed solution of ferric citrate and xylo-oligosaccharide; the mass ratio of ferric citrate to xylo-oligosaccharide is 1:1; the total concentration of ferric citrate and xylo-oligosaccharide in the mixed solution is 0.5-2.0%; S2, soaking the cigar tobacco leaves in the mixed solution for 3-5 min, and taking out the cigar tobacco leaves and naturally air-drying until no mixed solution remains; S3, controlling the water content of the obtained cigar tobacco leaf raw material in step S2, and performing fermentation treatment to obtain a dark cigar jacket product.

2. The process for preparation of dark fired cigar wrapper based on oxygen- augmented fermentation as claimed in claim 1 wherein, In step S1, the total concentration of ferric citrate and xylo-oligosaccharide in the mixed solution is 2.0%.

3. The process for preparation of aerated fermentation based dark fired cigar wrapper leaf according to claim 1, wherein, In step S3, the water content of the cigar tobacco leaf raw material is 28-30%.

4. The process for preparation of aerated fermentation based dark fired cigar wrapper leaf according to claim 1, wherein, In step S3, the water content of the cigar tobacco leaf raw material is 29%.

5. The process for preparation of aerated fermentation based dark fired cigar wrapper leaf according to claim 1, wherein, In step S3, when the center temperature of the cigar tobacco pile is higher than 50℃ or the temperature continuously decreases for 24 h, immediately perform pile turning treatment, and the specific method is: after the tobacco leaves are shaken and cooled to room temperature, fermentation is performed again, the relative humidity of the environment is not less than 75%, and the shaking time of the tobacco leaves is 0.5-1.0 h.

6. The process for the preparation of dark fired cigar leaf based on the aerobic fermentation according to any of claims 1 to 5, characterized in that, In step S3, during the fermentation treatment, the oxygen concentration in the fermentation environment is also controlled to be 28-30%, and pile turning treatment is also performed during the fermentation process, until the center temperature of the cigar tobacco pile no longer changes or the change amplitude is not more than 1℃, and then the fermentation is completed.

7. The process for preparation of dark fired cigar leaf based on oxygen- augmented fermentation as claimed in claim 6 wherein, In step S3, the oxygen concentration in the fermentation environment is 30%. In step S3, when the center temperature of the cigar tobacco pile is higher than 50℃ or the temperature continuously decreases for 24 h, immediately perform pile turning treatment, and the specific method is: after the tobacco leaves are shaken and cooled to room temperature, fermentation is performed again, the relative humidity of the environment is not less than 75%, and the shaking time of the tobacco leaves is 0.5-1.0 h.

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