A flue-curing color-fixing method for improving the oil content of tobacco leaves

Abstract

The present invention discloses a flue-curing color-fixing method for improving the oil content of tobacco leaves, which relates to the technical field of tobacco leaf modulation; the method includes measuring the thickness and moisture content of fresh tobacco leaves, calculating their average values, and substituting them into the calculation formulas for the wet-bulb temperature at the initial stage of color-fixing, the wet-bulb temperature at the final stage of color-fixing, and the total time of the color-fixing period. Specifically: Y1 = 3.0831X1 - 2.9684X2 + 35.5; Y2 = 3.0831X1 - 2.9684X2 + 37.5; Y3 = 8.2448X1 + 155.72X2; where: Y1 is the wet-bulb temperature at the initial stage of color-fixing; Y2 is the wet-bulb temperature at the final stage of color-fixing; Y3 is the total time of the color-fixing period; X1 is the average value of the moisture content of fresh tobacco leaves; X2 is the average value of the thickness of fresh tobacco leaves. The method of the present invention can accurately determine the wet-bulb temperature and color-fixing time in the flue-curing barn, solves the problem that the staged color-fixing is easily affected by the experience and subjective factors of technicians, significantly improves the convenience and accuracy of tobacco leaf baking, and also improves the quality of tobacco leaf baking and the oil content of the baked tobacco leaves.

Description

Technical Field

[0001] The invention relates to the technical field of tobacco leaf curing, and in particular to a flue-cured tobacco color fixing method for increasing the oil content of tobacco leaves. Background Art

[0002] Tobacco leaf curing, also known as drying, refers to the process of processing fresh tobacco leaves harvested at the mature stage of the process into dry tobacco leaves that meet the requirements of industrial raw materials through temperature and humidity adjustment, and a series of physical, physiological and biochemical changes. The harvested tobacco leaves contain 80%-90% moisture. Curing is one of the important measures in tobacco production. During the tobacco leaf curing period, especially the color fixing period, it is an important period for the transformation of internal substances in the tobacco leaves and the synthesis of aroma precursor substances. It is also a key stage for improving the oil content of tobacco leaves after curing. The complex physiological and biochemical changes that occur inside the leaves are all carried out with water as the medium. Different temperature and humidity conditions and color fixing time affect the dehydration of tobacco leaves and also affect the internal material transformation of tobacco leaves. The wet-bulb temperature can better reflect the moisture status in the curing room and the physiological reaction temperature of tobacco leaves. Therefore, the wet-bulb temperature in the curing room is an important factor affecting the quality of tobacco leaves.

[0003] At present, the setting of the wet-bulb temperature of tobacco leaves is mostly within the range of suitable wet-bulb temperatures in each stage specified in the baking technical specifications, and is artificially set according to the state of tobacco leaves. It is affected by subjective factors such as the technical experience accumulated by baking technicians over the years. Once the technicians make mistakes in judgment and setting, it is very easy to cause bad tobacco such as baking green and hanging ash, causing economic losses to tobacco farmers. At the same time, in the color setting stage of tobacco leaves, the existing technology mostly adopts a multi-stage method, that is, during the color setting period from 42°C to 54°C, most of them are fixed at 46°C and 50°C for stable temperature color setting, such as the three-stage five-step tobacco leaf baking process disclosed in the authorized patent CN1444879B. The multi-stage color setting has the following disadvantages: first, it increases the difficulty of judging the color setting in stages, and second, in the stable temperature and moisture removal stage, the humidity environment in the tobacco loading room of the curing room fluctuates within a certain range, affecting the baking quality of tobacco leaves and not conducive to the improvement of the oil content of tobacco leaves after baking. Summary of the invention

[0004] In view of the deficiencies of the above prior art, the present invention provides a method for color fixing of flue-cured tobacco for improving the oil content of tobacco leaves. The method adopts corresponding wet-bulb temperature at the initial color fixing stage, wet-bulb temperature at the final color fixing stage, and total time of the color fixing stage based on the moisture content and thickness of different tobacco leaves. The parameters of the color fixing stage can be accurately determined according to tobacco leaves with different baking characteristics, thereby improving the baking quality of tobacco leaves and the oil content of the baked tobacco leaves; at the same time, the temperature stabilization time is shortened, and the color is fixed by slowly heating up and removing moisture, thereby significantly improving the convenience and accuracy of tobacco leaf baking, which is specifically achieved through the following technologies:

[0005] The present invention provides a flue-cured tobacco color fixing method for increasing the oil content of tobacco leaves, comprising the following steps:

[0006] S1. Select the fresh tobacco leaves to be baked, measure the thickness and moisture content of the fresh tobacco leaves, and calculate their average values;

[0007] S2. Calculate the wet-bulb temperature at the initial stage of color fixation, the wet-bulb temperature at the final stage of color fixation, and the total time of the color fixation period of the flue-cured tobacco according to the average values of the thickness and moisture content rate obtained in step S1;

[0008] S3. Input the wet-bulb temperature at the initial stage of color fixation, the wet-bulb temperature at the final stage of color fixation, and the total time of the color fixation period obtained in step S2 into the baking automatic control instrument to carry out water loss and color fixation of the flue-cured tobacco.

[0009] The calculation formulas for the above-mentioned wet-bulb temperature at the initial stage of color fixation, the wet-bulb temperature at the final stage of color fixation, and the total time of the color fixation period are as follows:

[0010] Y1 = 3.0831X1 - 2.9684X2 + 35.5;

[0011] Y2 = 3.0831X1 - 2.9684X2 + 37.5;

[0012] Y3 = 8.2448X1 + 155.72X2;

[0013] Where: Y1 is the wet-bulb temperature at the initial stage of color fixation; Y2 is the wet-bulb temperature at the final stage of color fixation; Y3 is the total time of the color fixation period; X1 is the average value of the moisture content of the fresh tobacco leaves; X2 is the average value of the thickness of the fresh tobacco leaves.

[0014] Further, in step S1, the fresh tobacco leaves are the tobacco leaves before stringing after harvesting.

[0015] Furthermore, the number of the above-mentioned fresh tobacco leaves is 8 - 10 pieces.

[0016] The specific operation of the above step S3 is as follows: Set the dry-bulb temperature in the later stage of yellowing and the dry-bulb temperature at the initial stage of color fixation of the baking automatic control instrument, input the corresponding heating-up time of 3h, the constant-temperature time of 1h and the above-mentioned wet-bulb temperature at the initial stage of color fixation; then set the dry-bulb temperature at the final stage of color fixation, input the corresponding heating-up time of the above-mentioned total time of the color fixation period, the constant-temperature time of 1h and the above-mentioned wet-bulb temperature at the final stage of color fixation.

[0017] Further, the dry-bulb temperature in the later stage of yellowing is 42°C, the dry-bulb temperature at the initial stage of color fixation is 43°C, and the dry-bulb temperature at the final stage of color fixation is 54°C.

[0018] Further, the variety of the above-mentioned fresh tobacco leaves is Yunyan 87 or K326. The above-mentioned color fixation method of the present invention can be applied not only to the two tobacco leaf varieties, but also to other varieties not listed.

[0019] In a large number of practical processes, the inventor constructed the above calculation method for accurately determining the wet-bulb temperature at the initial stage of color fixation, the wet-bulb temperature at the end stage of color fixation, and the total time of the color fixation period by analyzing the changes in the dry-bulb temperature and wet-bulb temperature in the curing barn required for different fresh tobacco leaf moisture contents and thicknesses, determined the coefficients in the calculation formula, accurately determined the parameters of the color fixation period according to tobacco leaves with different baking characteristics, and significantly improved the convenience and accuracy of tobacco leaf baking, as well as the quality of tobacco leaf baking and the oil content of the baked tobacco leaves.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. The flue-curing color fixation method of the present invention constructs a determination method for the wet-bulb temperature at the initial stage of color fixation, the wet-bulb temperature at the end stage of color fixation, and the total time of the color fixation period based on the moisture content and thickness of tobacco leaves, can accurately determine the wet-bulb temperature and color fixation time in the curing barn, and solves the problem that the color fixation in stages is easily affected by the experience and subjective factors of technicians.

[0022] 2. The wet-bulb temperature in the curing barn is an important factor affecting the quality of tobacco leaves. By accurately determining the wet-bulb temperature and performing moisture removal and color fixation by slow temperature rise, the convenience and accuracy of tobacco leaf baking are significantly improved, as well as the quality of tobacco leaf baking and the oil content of the baked tobacco leaves. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a result diagram of flue-curing color fixation of Yunyan 87 in Experimental Example 1;

[0024] Figure 2 It is a result diagram of flue-curing color fixation of Yunyan 87 in Comparative Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] For the flue-curing color fixation method for improving the oil content of tobacco leaves disclosed in the embodiment of the present invention, the inventor conducted flue-curing color fixation and economic character comparison for all tobacco leaf varieties. In order to simplify the steps of this implementation method, the present invention only lists the flue-curing color fixation process and economic character comparison results of Yunyan 87 and K326.

[0027] Example 1

[0028] Select 8 representative tobacco leaves of Yunyan 87 from Lichuan, Hubei as the tobacco leaves to be baked before stringing after harvesting. Obtain the flue-curing high-oil content color fixation method for Yunyan 87 according to the following method:

[0029] S1. Measure the moisture content values and thickness values of 8 fresh tobacco leaves to be tested respectively, calculate the average values of the two indicators, and obtain that the average value of the moisture content of the fresh tobacco leaves is 0.8616 and the average value of the thickness is 0.3858;

[0030] S2. Substitute the average values of the thickness and moisture content of the measured fresh tobacco leaves into the calculation formulas for the wet-bulb temperature at the initial stage of color fixation, the wet-bulb temperature at the final stage of color fixation, and the total time of the color fixation period;

[0031] Among them, the calculation formulas for the wet-bulb temperature at the initial stage of color fixation, the wet-bulb temperature at the final stage of color fixation, and the total time of the color fixation period are as follows respectively:

[0032] Y1 = 3.0831X1 - 2.9684X2 + 35.5;

[0033] Y2 = 3.0831X1 - 2.9684X2 + 37.5;

[0034] Y3 = 8.2448X1 + 155.72X2;

[0035] In the formula: Y1 is the wet-bulb temperature at the initial stage of color fixation; Y2 is the wet-bulb temperature at the final stage of color fixation; Y3 is the total time of the color fixation period; X1 is the average value of the moisture content of the fresh tobacco leaves; X2 is the average value of the thickness of the fresh tobacco leaves;

[0036] Substitute the average value of the moisture content of the fresh tobacco leaves 0.8616 and the average value of the thickness 0.3858 obtained in step S1 into the formula to obtain the following results:

[0037] Y1 = 3.0831×0.8616 - 2.9684×0.3858 + 35.5 = 37.01;

[0038] Y2 = 3.0831×0.8616 - 2.9684×0.3858 + 37.5 = 39.01;

[0039] Y3 = 8.2448×0.8616 + 155.72×0.3858 = 67.19;

[0040] S3. Input the calculated wet-bulb temperature Y1 at the initial stage of color fixation, the wet-bulb temperature Y2 at the final stage of color fixation, and the total time Y3 of the color fixation period into the baking automatic controller to implement baking. Specifically:

[0041] Set the dry-bulb temperature in the later stage of yellowing of the baking automatic controller to 42°C, set the dry-bulb temperature at the initial stage of color change to 43°C, input the calculated wet-bulb temperature Y1 at the initial stage of color fixation as 37°C, the corresponding temperature increase time is 3h, and the corresponding stable time is 1h; then set the dry-bulb temperature at the final stage of color fixation to 54°C, input the calculated wet-bulb temperature Y2 at the final stage of color fixation as 39°C, the corresponding temperature increase time is the total time Y3 of the color fixation period is 67h, and the corresponding stable time is 1h.

[0042] The result diagram of the color change during the baking of Yunyan 87 in this embodiment is as Figure 1 shown. It can be seen that there are fewer variegated leaves in the baked tobacco leaves obtained by using the baking technology of this embodiment, the leaf surface is softer, and the oil content is relatively sufficient.

[0043] Example 2

[0044] Select K326 from Lichuan, Hubei as the tobacco leaves to be baked, and select 8 representative tobacco leaves before stringing after harvesting. The specific method of fixing the color with high oil content in this experimental example refers to Example 1.

[0045] In this embodiment, the average moisture content of the fresh tobacco leaves is calculated to be 0.8143, and the average thickness is 0.3946;

[0046] The wet-bulb temperature at the initial stage of color fixation, the wet-bulb temperature at the final stage of color fixation, and the total time of the color fixation period are calculated as follows:

[0047] Y1 = 3.0831×0.8143 - 2.9684×0.3946 + 35.5 = 36.8;

[0048] Y2 = 3.0831×0.8143 - 2.9684×0.3946 + 37.5 = 38.8;

[0049] Y3 = 8.2448×0.8143 + 155.72×0.3946 = 68.2.

[0050] Comparative Example 1

[0051] The difference between this comparative example and Example 1 is that the tobacco leaves to be baked in the same area are baked according to the local conventional three-stage and five-step baking process (a conventional technology in the field, and the specific method can refer to the method of Chinese authorized patent CN1444879).

[0052] The result diagram of the color change during the baking of Yunyan 87 in this comparative example is as Figure 2 shown. It can be seen that the proportion of variegated leaves in the baked tobacco leaves obtained by using the baking technology of this comparative example is relatively high, the tobacco leaves are stiff, and the oil content is insufficient.

[0053] Comparative Example 2

[0054] The difference between this comparative example and Example 2 is that the tobacco leaves to be baked in the same area are baked according to the local conventional three-stage and five-step baking process (a conventional technology in the field, and the specific method can refer to the method of Chinese authorized patent CN1444879).

[0055] Application Example: Comparison of the Economic Characters of the Baked Tobacco Leaves in Examples and Comparative Examples

[0056] For the specific color-fixing period parameters of the methods in Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, see Table 1-2 below. It can be seen from the table that the total color-fixing time of Example 1 is 69 h, of which 67 h is for continuous temperature rise during color-fixing; while the total color-fixing time of Comparative Example 1 is 64 h, and the total temperature stabilization time at 44 °C, 48 °C, and 54 °C is 34 h. The total color-fixing time of Example 2 is 68 h, of which 66 h is for continuous temperature rise during color-fixing; while the total color-fixing time of Comparative Example 2 is 66 h, and the total temperature stabilization time at 44 °C, 48 °C, and 54 °C is 36 h.

[0057] Table 1 Parameters of the color-fixing period in Example 1 and Comparative Example 1

[0058]

[0059] Table 2 Parameters of the color-fixing period in Example 1 and Comparative Example 1

[0060]

[0061] The quality of the flue-cured tobacco obtained by using the color-fixing methods of the examples and comparative examples is as follows:

[0062] 1. Appearance quality of the cured tobacco leaves

[0063] According to the applicant's enterprise internal standard, the appearance of the cured tobacco leaves in the examples and comparative examples was evaluated, mainly including indicators such as color, maturity, leaf structure, and oil content. The specific evaluation results are shown in Table 3 below.

[0064] Table 3 Evaluation results of the appearance quality of the cured tobacco leaves in Examples 1-2 and Comparative Examples 1-2

[0065] Processing Color Maturity Leaf structure Identity Oil content Chromaticity Total Example 1 8.3 8.4 8.5 7.8 7.5 6.6 47.1 Comparative example 1 7.2 7.8 7.9 7.5 6.0 5.4 41.8 Example 2 8.5 8.5 8.5 8.0 7.5 6.5 47.5 Comparative example 2 7.6 8.0 8.0 7.5 6.5 5.5 43.1

[0066] It can be seen from the appearance quality of the cured tobacco leaves in the table that compared with Comparative Examples 1-2, the appearance quality in Examples 1-2 has been significantly improved, and the oil content of the tobacco leaves has been significantly increased.

[0067] 2. Comparison of the sensory quality of the cured tobacco leaves

[0068] According to the "Method for Sensory Evaluation of Tobacco and Tobacco Products" YC / T 138, the sensory quality of the cured tobacco leaves in the examples and comparative examples was evaluated. The specific evaluation results are shown in Table 4 below. The results show that compared with the color-fixing method of the comparative example, the sensory smoking quality of the cured tobacco leaves by the color-fixing method of the example has been significantly improved, mainly manifested in the reduction of miscellaneous odors, the increase in the amount of aroma, and the improvement of the quality of the aroma. The sensory evaluation quality of the cured tobacco leaves with better maturity is better.

[0069] Table 4 Comparison of the sensory quality of the cured tobacco leaves in Examples 1-2 and Comparative Examples 1-2

[0070]

[0071] 3. Comparison of Economic Characters of Flue-cured Tobacco Leaves after Baking

[0072] According to the standard of flue-cured tobacco grade classification basis in this field, GB / T 2635 - 1992, the flue-cured tobacco leaves after baking in the examples and comparative examples were rated and evaluated for economic characters. The specific evaluation results are shown in Table 5 below. It can be seen that the color-fixing method in the examples effectively reduces the proportion of mottled tobacco, and the proportion of superior-grade tobacco, the proportion of orange-yellow tobacco, and the average price of the flue-cured tobacco leaves after baking have all increased.

[0073] Table 5 Economic Characters of Flue-cured Tobacco Leaves after Baking

[0074]

[0075]

[0076] Thus, it can be seen that by using the color-fixing method of the examples, the evaluations of the appearance, sensory properties, and economic characters of the flue-cured tobacco leaves obtained by baking are all superior to those of the comparative examples. The present invention provides a new method for color-fixing of flue-cured tobacco leaves. At the same time, the baking color-fixing parameters can be objectively calculated, and the measurement methods of the required index parameters are simple and easy to operate, and are not affected by individual experience differences and subjective factors. The optimal color-fixing parameters of flue-cured tobacco leaves with different qualities can be obtained according to the color-fixing method of the present invention, and color-fixing can be implemented by the method of continuous temperature rise color-fixing, which can improve the appearance, sensory quality, and oil content of flue-cured tobacco leaves after baking.

[0077] The above specific embodiments have described the implementation of the present invention in detail. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solutions of the present invention, and these simple variations all belong to the protection scope of the present invention.

Claims

1. A flue-curing color-fixing method for improving the oil content of tobacco leaves, characterized in that, It includes the following steps: S1. Select fresh tobacco leaves to be baked, measure the thickness and moisture content of the fresh tobacco leaves, and calculate their average values; S2. Calculate the wet-bulb temperature at the initial stage of color fixing, the wet-bulb temperature at the final stage of color fixing, and the total time of the color-fixing period of the flue-cured tobacco according to the average values of the thickness and moisture content rate obtained in step S1; The calculation formulas for the wet-bulb temperature at the initial stage of color fixing, the wet-bulb temperature at the final stage of color fixing, and the total time of the color-fixing period are as follows: Y1 = 3.0831X1 - 2.9684X2 + 35.5; Y2 = 3.0831X1 - 2.9684X2 + 37.5; Y3 = 8.2448X1 + 155.72X2; In the formula: Y1 is the wet-bulb temperature at the initial stage of color fixing; Y2 is the wet-bulb temperature at the final stage of color fixing; Y3 is the total time of the color-fixing period; X1 is the average moisture content of the fresh tobacco leaves; X2 is the average thickness of the fresh tobacco leaves; S3. Input the wet-bulb temperature at the initial stage of color fixing, the wet-bulb temperature at the final stage of color fixing, and the total time of the color-fixing period obtained in step S2 into the baking automatic control instrument to carry out color fixing of the flue-cured tobacco.

2. The flue-cured tobacco color-fixing method for improving the oil content of tobacco leaves according to claim 1, characterized in that, In step S1, the fresh tobacco leaves are the tobacco leaves before stringing after harvesting.

3. The flue-cured tobacco color-fixing method for improving the oil content of tobacco leaves according to claim 2, wherein, The number of the fresh tobacco leaves is 8 - 10 pieces.

4. The flue-curing color-fixing method for improving the oil content of tobacco leaves according to claim 1, wherein The specific operation of step S3 is as follows: Set the dry-bulb temperature in the later stage of yellowing and the dry-bulb temperature at the initial stage of color fixing of the baking automatic control instrument, input the corresponding heating-up time of 3h, the constant-temperature time of 1h, and the wet-bulb temperature at the initial stage of color fixing; then set the dry-bulb temperature at the final stage of color fixing, and input the corresponding heating-up time of the total time of the color-fixing period, the constant-temperature time of 1h, and the wet-bulb temperature at the final stage of color fixing.

5. The flue-curing color-fixing method for improving the oil content of tobacco leaves according to claim 4, characterized in that, The dry-bulb temperature in the later stage of yellowing is 42°C, the dry-bulb temperature at the initial stage of color fixing is 43°C, and the dry-bulb temperature at the final stage of color fixing is 54°C.

6. The flue-curing color-fixing method for improving the oil content of tobacco leaves according to any one of claims 1-5, characterized in that, The variety of the fresh tobacco leaves is Yunyan 87 or K326.

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