Baking method for improving high-altitude low-quality tobacco leaves

Abstract

The invention discloses a baking method for improving high-altitude low-quality tobacco leaves, and relates to the technical field of tobacco leaf baking. The method comprises the steps of yellowing stage control, color fixing stage control and stem drying stage control, and the core is the step of setting low-temperature stimulation of tobacco leaf withering in the later stage of the yellowing stage: adjusting the dry-bulb temperature to 38 DEG C from 42 DEG C, maintaining the wet-bulb temperature to 35.5 DEG C, and baking for 10-16 hours at the dry-bulb temperature and the wet-bulb temperature, so that the endogenous enzyme activity of the tobacco leaves is activated, chlorophyll degradation is forcefully started, and the tobacco leaf withering rate is increased. And then yellowing continues to be completed, and sufficient yellowing, excellent color fixing and thorough drying of the tobacco leaves are finally achieved through temperature rising in the color fixing period and the stem drying period. According to the method, the technical bottleneck that the chlorophyll content of the high-altitude low-quality tobacco leaves is high but a degradation system is dormant is solved, the tobacco leaves are sufficiently and uniformly yellowed, the color fixation is stable, the yellow tobacco rate and the middle-first-class tobacco ratio of the flue-cured tobacco leaves are remarkably increased, the color, the oil content and the sensory evaluation quality of the tobacco leaves are effectively improved, and finally the average price is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tobacco leaf curing, in particular to a curing method for improving high-altitude low-quality tobacco leaves. BACKGROUND

[0002] Yunnan is the main producing area of high-quality flue-cured tobacco in China, with low latitude, high altitude, large diurnal temperature difference and other diverse three-dimensional climate, which provides a good ecological basis for the formation of high-quality tobacco style of clear and sweet aroma. In recent years, with the adjustment of tobacco planting layout, the tobacco area has gradually shifted to high-altitude areas above 2000 meters. The unique continuous low temperature and strong radiation stress in high-altitude environment has a profound impact on the normal growth and development of tobacco leaves, directly leading to the formation of low-quality tobacco leaves. This kind of tobacco leaves shows unique physiological characteristics at harvest time: leaf is brittle and hard, leaf color is dark green, and the most core and prominent problem is that the content of chlorophyll is abnormally high. Studies have shown that this may be due to the inhibition of chloroplast function by environmental stress, which leads to the disruption of the metabolic balance of chlorophyll synthesis and degradation, so that it still maintains the state of greed for green at the mature stage. Greed for green refers to the phenomenon that tobacco plants still maintain an abnormal dark green color in the leaves, chlorophyll degradation is slow or stagnant, and it is difficult to turn yellow normally after the growth and development enters the mature stage.

[0003] When such tobacco leaves enter the curing link, their inherent physiological defects are dramatically amplified under the conventional three-stage curing process. The extremely high chlorophyll background value requires stronger degradation power, while the inhibited physiological state makes the activity level of chlorophyll degradation enzyme low, resulting in extremely slow initiation of yellowing process and difficulty in completely degrading chlorophyll during the entire curing period. Incomplete chlorophyll degradation directly leads to high green rate and high rate of mixed color in cured tobacco leaves, with rigid color and dull color, which seriously reduces the appearance quality of tobacco leaves. The more serious problem is that the synthesis and transformation of aroma precursor are often hindered, which is accompanied by abnormal chlorophyll metabolism. This leads to insufficient aroma, poor aroma quality, heavy green and mixed aroma in cured tobacco leaves, significantly reduces sensory evaluation quality, and ultimately causes damage to the economic benefits of tobacco farmers.

[0004] The root cause is that the existing conventional curing process is a steady-state heating universal scheme, which cannot break the physiological inertia of high-altitude low-quality tobacco leaves and cannot effectively activate the activity of the chlorophyll degradation system. Therefore, there is an urgent need in the art for a special curing method that can specifically awaken the physiological potential of tobacco leaves, effectively drive chlorophyll degradation and simultaneously improve aroma quality. SUMMARY

[0005] In view of the above-mentioned defects or deficiencies in the prior art, the present application provides a curing method for improving high-altitude low-quality tobacco leaves, which sets a low-temperature stimulation step for tobacco leaf senescence in the yellowing middle period, effectively breaks the physiological inertia of tobacco leaves, activates endogenous enzyme activity, and significantly promotes chlorophyll degradation and aroma precursor transformation of high-altitude low-quality tobacco leaves.

[0006] The present application provides a method for improving the baking of high-altitude low-quality tobacco leaves, comprising: loading the tobacco leaves into a baking room and igniting; in the early stage of the yellowing period, the dry and wet ball temperatures are raised from room temperature to 32℃, and the tobacco leaves are baked at the above dry and wet ball temperatures for 4-6 hours; then the dry ball temperature is raised to 35℃, and the wet ball temperature is raised to 34℃, and the tobacco leaves are baked at the above dry and wet ball temperatures for 10-12 hours until the tips of the high-temperature layer tobacco leaves become soft; in the middle stage of the yellowing period, the dry ball temperature is raised to 38℃, and the wet ball temperature is raised to 35.5℃, and the tobacco leaves are baked at the above dry and wet ball temperatures for 10 hours until the high-temperature layer tobacco leaves are 5-6 yellowed; then the dry ball temperature is raised to 42℃, and the wet ball temperature is maintained at 35.5℃, and the tobacco leaves are baked at the above dry and wet ball temperatures for 2-4 hours; in the late stage of the yellowing period, the dry ball temperature is lowered from 42℃ to 38℃, and the wet ball temperature is maintained at 35.5℃, and the tobacco leaves are baked at the above dry and wet ball temperatures for 10-16 hours until the high-temperature layer tobacco leaves are fully wilted, the leaf color changes from dark green to light green and yellow, and the leaf veins begin to soften; the dry ball temperature is raised to 42℃ again, and the wet ball temperature is maintained at 35.5℃, and the tobacco leaves are baked at the above dry and wet ball temperatures for 16-20 hours until the high-temperature layer tobacco leaves are yellow with green veins and hooked tips; in the early stage of the color fixing period, the dry ball temperature is raised to 48℃, and the wet ball temperature is raised to 36℃, and the tobacco leaves are baked at the above dry and wet ball temperatures for 16-20 hours until the high-temperature layer tobacco leaves are small rolled cylinders; in the late stage of the color fixing period, the dry ball temperature is raised to 54℃, and the wet ball temperature is raised to 37℃, and the tobacco leaves are baked at the above dry and wet ball temperatures for 18-20 hours until the whole furnace tobacco leaves are fully dried; in the dry vein period, the dry ball temperature is raised to 68℃, and the wet ball temperature is raised to 39℃, and the tobacco leaves are baked at the above dry and wet ball temperatures for 24-36 hours until the whole baking room tobacco leaves are dried.

[0007] Further, in the early stage of the yellowing period, the temperature raising rate of the dry ball temperature from room temperature to 32℃ is 1℃ / 2h-1℃ / 4h, and the temperature raising rate of the dry ball temperature to 35℃ is 1℃ / h.

[0008] Further, in the middle stage of the yellowing period, the temperature raising rate of the dry ball temperature to 37℃-39℃ is 1℃ / 2h, and the temperature raising rate of the dry ball temperature to 41℃-43℃ is 1℃ / 0.5h.

[0009] Further, in the late stage of the yellowing period, the temperature lowering rate of the dry ball temperature from 42℃ to 38℃ is 1℃ / 0.25h, and the temperature raising rate of the dry ball temperature to 42℃ again is 1℃ / 2h.

[0010] Further, in the early stage of the color fixing period, the dry ball temperature is raised to 48 DEG C at a rate of 1 DEG C / 2h.

[0011] Further, in the late stage of the color fixing period, the dry ball temperature is raised to 54 DEG C at a rate of 1 DEG C / 2h.

[0012] Further, in the dry muscle period, the dry ball temperature is raised to 68 DEG C at a rate of 1 DEG C / h.

[0013] Further, the tobacco leaves are loaded into the curing barn, and the tobacco is loaded at a density of 42-45 kg / m 3 Further, the curing barn is an air flow descending type dense curing barn.

[0014] Further, the curing barn is an air flow descending type dense curing barn.

[0015] Further, the tobacco leaves include any one of K326, Honghua Dajinyuan and Yunyan 87.

[0016] The method for improving the curing of low-quality tobacco leaves at high altitudes has the following beneficial effects: In the middle stage of the yellowing period, the dry ball temperature is steadily raised, which makes necessary thermal preparation for the subsequent low-temperature stimulation, makes the tobacco leaf cells more sensitive to the upcoming temperature change, and lays the foundation for maximizing the reversion effect. In the late stage of the yellowing period, the dry ball temperature is lowered from 42 DEG C to 38 DEG C, the wet ball temperature is maintained at 35.5 DEG C, and mild physical stress is applied to the tobacco leaves, which effectively activates the activity of endogenous enzymes in the cells, especially chlorophyll degradation enzymes, and is the core key to starting and accelerating the chlorophyll degradation process. The curing method has clear process steps, simple and clear dry ball temperature setting and wet ball temperature control, is easy to master and promote, innovatively sets a unique low-temperature stimulation tobacco leaf reversion step in the yellowing period, stimulates chlorophyll degradation through precise temperature and humidity control, solves the fundamental technical bottleneck of high chlorophyll content and dormant degradation system of low-quality tobacco leaves at high altitudes, overcomes the fundamental technical bottleneck of slow chlorophyll degradation, difficult yellowing and easy curing green, realizes sufficient and uniform yellowing of tobacco leaves, stable color fixing, significantly improves the yellow tobacco rate and the proportion of medium and high grade tobacco after curing, effectively improves the color, oil and sensory evaluation quality of the tobacco leaves, and finally realizes the price increase. BRIEF DESCRIPTION OF DRAWINGS

[0017] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings: Figure 1is a flowchart of a method for improving the baking of low-quality tobacco leaves at high altitudes according to an embodiment of the present application; Figure 2 is a temperature and humidity change line graph of a method for improving the baking of low-quality tobacco leaves at high altitudes according to an embodiment of the present application. DETAILED DESCRIPTION

[0018] To make the objectives, technical solutions, and superiorities of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0019] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an", and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0020] It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present application to describe obtaining modules, these obtaining modules should not be limited by these terms. These terms are only used to distinguish the obtaining modules from each other.

[0021] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if it is determined" or "if [a stated condition or event] is detected" can be interpreted to mean "when it is determined" or "in response to determining" or "when [a stated condition or event] is detected" or "in response to detecting [a stated condition or event]".

[0022] It should be noted that the orientation words "up", "down", "left", "right", etc. described in the embodiments of the present application are described from the angle shown in the drawings, and should not be understood as limiting the embodiments of the present application. In addition, in the context, it should also be understood that when referring to an element being formed "on" or "under" another element, it can be directly formed "on" or "under" another element, or indirectly formed "on" or "under" another element through an intermediate element.

[0023] Reference Figure 1 The embodiments of the present application provide a method for improving the baking of low-quality tobacco leaves at high altitudes, comprising: Step S101, the tobacco is loaded into the curing barn, wherein the tobacco includes any one of K326, Honghuadajinyuan and Yunyan87, the curing barn is a down-flow type bulk curing barn, the tobacco is bundled according to 7-8 kg / pole or 10-12 kg / clamp, if pole bundling is used, the tobacco stalks are bound on the poles according to 7-8 kg / pole, if clamp bundling is used, the tobacco stalks are clamped in the tobacco clamp according to 10-12 kg / clamp, and then the tobacco is loaded at a density of 42-45 kg / m 3 The curing barn is closed and ignited; Step S102, in the early yellowing stage, the dry bulb temperature is increased from room temperature to 32℃ at a temperature increasing rate of 1℃ / 2h-1℃ / 4h, the wet bulb temperature is increased from room temperature to 32℃, the tobacco is baked at the above dry and wet bulb temperatures for 4-6h; then the dry bulb temperature is increased to 35℃ at a temperature increasing rate of 1℃ / h, the wet bulb temperature is increased to 34℃, and the tobacco is baked at the above dry and wet bulb temperatures for 10-12h, until the high temperature layer of tobacco leaves is soft at the tip; Step S103, in the middle yellowing stage, the dry bulb temperature is increased to 38℃ at a temperature increasing rate of 1℃ / 2h, and the wet bulb temperature is increased to 35.5℃, the tobacco is baked at the above dry and wet bulb temperatures for 10h, until the high temperature layer of tobacco leaves is 5-6 yellow; then the dry bulb temperature is increased to 42℃ at a temperature increasing rate of 1℃ / 0.5h, and the wet bulb temperature is maintained at 35.5℃, the tobacco is baked at the above dry and wet bulb temperatures for 2-4h; this step steadily increases the dry bulb temperature, which is necessary for the subsequent low temperature stimulation, makes the tobacco cells more sensitive to the upcoming temperature change, and lays the foundation for maximizing the senescence effect; the senescence creates a low temperature stimulation environment, thereby triggering the physiological senescence and enzyme activity of the tobacco, and breaking the physiological inertia of the tobacco, so as to lay the foundation for the subsequent full yellowing and aroma substance formation; Step S104, in the late yellowing stage, the dry bulb temperature is adjusted back to 38℃ from 42℃ at a temperature decreasing rate of 1℃ / 0.25h, the wet bulb temperature is maintained at 35.5℃, the tobacco is baked at the above dry and wet bulb temperatures for 10-16h, until the high temperature layer of tobacco leaves is fully wilted, the leaf color is changed from dark green to light green and generally yellow, and the leaf veins begin to soften; the dry bulb temperature is increased to 42℃ again at a temperature increasing rate of 1℃ / 2h, the wet bulb temperature is maintained at 35.5℃, and the tobacco is baked at the above dry and wet bulb temperatures for 16-20h, until the high temperature layer of tobacco leaves is yellow with green veins and curled edges; this step adjusts the dry bulb temperature back to 38℃ from 42℃ and maintains the wet bulb temperature at 35.5℃, which exerts a mild physical stress on the tobacco, effectively activates the activity of endogenous enzymes in the cells, especially the chlorophyll degradation enzyme, and is the core and key to starting and accelerating the chlorophyll degradation process.

[0024] Step S105: In the early stage of color fixation, the dry bulb temperature is raised to 48°C and the wet bulb temperature is raised to 36°C at a heating rate of 1°C / 2h. The tobacco leaves are baked at the above dry and wet bulb temperatures for 16~20h until they reach the high temperature layer. Step S106: In the later stage of the color fixation period, the dry bulb temperature is raised to 54°C and the wet bulb temperature is raised to 37°C at a heating rate of 1°C / 2h. The leaves are baked at the above dry and wet bulb temperatures for 18-20h until all tobacco leaf tissue in the oven is completely dry. Step S107: During the drying period, the dry bulb temperature is raised to 68°C and the wet bulb temperature is raised to 39°C at a heating rate of 1°C / h. The tobacco leaves are then baked at the above dry and wet bulb temperatures for 24-36 hours until the tobacco leaves in the entire curing barn are dry.

[0025] Example 1 In a tobacco-growing area at an altitude of 2250 meters in Xiangyun County, Dali Prefecture, a typical low-quality tobacco field caused by environmental stress was selected. The tobacco variety harvested was K326, and the middle leaves were selected. The characteristics of the harvested leaves were: brittle and hard leaves, dark green color, uneven maturity observed in the field, and significantly higher chlorophyll content than normal tobacco leaves. The harvested fresh tobacco leaves were woven into poles using conventional methods, and the woven tobacco leaves were then distributed at a rate of 42 kg / m². 3 The smoke density is adjusted, and the smoke is loaded into a dense drying oven with descending airflow. The oven is then dried using the drying method provided in this embodiment of the invention. See the temperature and humidity change line graph for Example 1. Figure 2 The specific steps are as follows: The tobacco leaves are loaded into the curing barn and then sealed and ignited. In the early stage of yellowing, the dry bulb temperature was raised from room temperature to 32°C and the wet bulb temperature was raised from room temperature to 32°C at a rate of 1°C / 2h. The leaves were baked at the above dry and wet bulb temperatures for 4h. Then, the dry bulb temperature was raised to 35°C and the wet bulb temperature was raised to 34°C at a rate of 1°C / h. The leaves were baked at the above dry and wet bulb temperatures for 12h until the tips of the tobacco leaves in the high-temperature layer softened. During the middle of the yellowing stage, the dry-bulb temperature is increased to 38°C at a rate of 1°C / 2h, while the wet-bulb temperature is increased to 35.5°C. The leaves are then baked at these dry and wet-bulb temperatures for 10h until the tobacco leaves in the high-temperature layer are 50-60% yellow. Then, the dry-bulb temperature is increased to 42°C at a rate of 1°C / 0.5h, while the wet-bulb temperature is maintained at 35.5°C. The leaves are then baked at these dry and wet-bulb temperatures for 2h. In the later stages of yellowing, the dry-bulb temperature was slowly reduced from 42℃ to 38℃ at a cooling rate of 1℃ / 0.25h, while maintaining the wet-bulb temperature at 35.5℃. The leaves were baked at these dry and wet-bulb temperatures for 12h until the tobacco leaves in the high-temperature layer were fully wilted, the leaf color changed from dark green to light green and generally turned yellow, and the leaf veins began to soften. The dry-bulb temperature was then raised back to 42℃ at a heating rate of 1℃ / 2h, while maintaining the wet-bulb temperature at 35.5℃. The leaves were baked at these dry and wet-bulb temperatures for 20h until the tobacco leaves in the high-temperature layer had green veins, yellow leaves, hooked tips, and curled edges.

[0026] In the early stage of color fixation, the dry ball temperature is increased to 48℃ at a rate of 1℃ / 2h, the wet ball temperature is increased to 36℃, and the tobacco is baked for 20h at the above dry and wet ball temperatures until the high-temperature layer of tobacco is baked; In the late stage of color fixation, the dry ball temperature is increased to 54℃ at a rate of 1℃ / 2h, the wet ball temperature is increased to 37℃, and the tobacco is baked for 20h at the above dry and wet ball temperatures until the whole-oven tobacco is baked to dryness; In the dry muscle period, the dry ball temperature is increased to 68℃ at a rate of 1℃ / h, the wet ball temperature is increased to 39℃, and the tobacco is baked for 36h at the above dry and wet ball temperatures until the whole-barn tobacco is baked to dryness.

[0027] Example 2 In the tobacco-growing area at an altitude of 2250m in Xiangyun County, Dali, a typical low-quality tobacco field formed due to environmental stress is selected, the tobacco variety is K326, and the part is middle leaves, which are characterized by brittle and hard leaves, dark green color, uneven maturity observed in the field, and significantly higher chlorophyll content than normal tobacco leaves. The harvested fresh tobacco leaves are bundled according to the conventional method, the bundled tobacco leaves are loaded into the air-lowering type intensive curing barn at a loading density of 42kg / m 3 The tobacco leaves are loaded into the curing barn and ignited after being sealed; The tobacco leaves are loaded into the curing barn and ignited after being sealed; In the early stage of yellowing, the dry ball temperature is increased to 32℃ at a rate of 1℃ / 2h from room temperature, the wet ball temperature is increased to 32℃ from room temperature, and the tobacco is baked for 6h at the above dry and wet ball temperatures, then the dry ball temperature is increased to 35℃ at a rate of 1℃ / h, the wet ball temperature is increased to 34℃, and the tobacco is baked for 12h at the above dry and wet ball temperatures until the leaf tips of the high-temperature layer of tobacco are soft; In the middle stage of yellowing, the dry ball temperature is increased to 38℃ at a rate of 1℃ / 2h, and the wet ball temperature is increased to 35.5℃ at the same time, and the tobacco is baked for 10h at the above dry and wet ball temperatures until the high-temperature layer of tobacco is 5-6 yellow; then the dry ball temperature is increased to 42℃ at a rate of 1℃ / 0.5h, the wet ball temperature is maintained at 35.5℃, and the tobacco is baked for 4h at the above dry and wet ball temperatures; In the late stage of yellowing, the dry ball temperature is slowly adjusted back to 38℃ at a rate of 1℃ / 0.25h from 42℃, the wet ball temperature is maintained at 35.5℃, and the tobacco is baked for 16h at the above dry and wet ball temperatures until the high-temperature layer of tobacco is fully wilted, the leaf color is changed from dark green to light green and generally yellow, and the leaf veins begin to soften; the dry ball temperature is increased to 42℃ at a rate of 1℃ / 2h, the wet ball temperature is maintained at 35.5℃, and the tobacco is baked for 18h at the above dry and wet ball temperatures until the high-temperature layer of tobacco is yellow with green veins and hooked tips.

[0028] In the early stage of color fixation, the dry ball temperature is increased to 48℃ at a rate of 1℃ / 2h, the wet ball temperature is increased to 36℃, and the tobacco is baked for 18h at the above dry and wet ball temperatures until the high-temperature layer of tobacco is baked into small rolls; In the middle stage of color fixation, the dry ball temperature is increased to 54℃ at a rate of 1℃ / 2h, the wet ball temperature is increased to 37℃, and the tobacco is baked for 20h at the above dry and wet ball temperatures until the whole-oven tobacco is baked into dry tobacco. In the dry muscle period, the dry ball temperature is increased to 68℃ at a rate of 1℃ / h, the wet ball temperature is increased to 39℃, and the tobacco is baked for 30h at the above dry and wet ball temperatures until the whole-baking room tobacco is baked into dry tobacco.

[0029] Comparative Example 1 In the tobacco-growing area at an altitude of 2250m in Xiangyun County, Dali, a typical low-quality tobacco field formed due to environmental stress was selected from the same batch and the same plot as Example 1. The harvested fresh tobacco leaves were bundled according to the conventional method, and then loaded into a down-flow dense curing barn at a loading density of 42kg / m 3 .

[0030] This comparative example aims to explore the influence of extending the 42℃ stable temperature time. Except for the stable temperature time of 42℃ in the middle stage of the yellowing period, the other baking steps of Comparative Example 1 are the same as those of Example 1. In the middle stage of the yellowing period, the dry ball temperature is increased to 42℃ at a rate of 1℃ / 0.5h, the wet ball temperature is maintained at 35.5℃, and the tobacco is baked for 6h at the above dry and wet ball temperatures.

[0031] Comparative tests were conducted according to the above curing method of Comparative Example 1 and the curing methods of Example 1 and Example 2, and the appearance quality, main aroma components and sensory evaluation quality of the cured tobacco leaves were comprehensively evaluated, and the results are shown in Tables 1 to 3.

[0032] Table 1 Comparison table of appearance quality and economic characters of cured tobacco leaves Table 1 shows that the economic characters of the tobacco leaves baked by the curing methods of Example 1 and Example 2 are significantly better than those of the tobacco leaves baked by the curing method of Comparative Example 1, which is specifically manifested in that: The ratio of middle and upper grade tobacco leaves of Example 1 is higher than that of Comparative Example 1 by 6.8 percentage points, the grade-out tobacco leaves are lower than those of Comparative Example 1 by 6.6 percentage points, and the average price is higher than that of Comparative Example 1 by 1.6 yuan / kg; The ratio of middle and upper grade tobacco leaves of Example 2 is higher than that of Comparative Example 1 by 5.7 percentage points, the grade-out tobacco leaves are lower than those of Comparative Example 1 by 5.2 percentage points, and the average price is higher than that of Comparative Example 1 by 1.3 yuan / kg.

[0033] Table 2 Comparison table of main aroma components of tobacco leaves Table 2 shows that the aroma substance content of the tobacco leaves baked by the baking method of the present application embodiment 1 and embodiment 2 is obviously better than that of the tobacco leaves baked by the baking method of the comparative example 1, which is specifically shown as follows: The total aroma component content of the tobacco leaves baked by the present application embodiment 1 is as high as 408.77 μg / g, which is increased by 43.60 μg / g compared with the comparative example 1, and is increased by about 11.94%; the increase in key aroma components is particularly significant: neophytadiene is increased by about 11.42% compared with the comparative example 1, β-damascenone is increased by about 59.76% compared with the comparative example 1, dihydrojasmone is increased by about 58.93% compared with the comparative example 1; cembrene 2 is increased by about 6.49% compared with the comparative example 1, phenylacetaldehyde is increased by about 53.02% compared with the comparative example 1; furfural is increased by about 31.40% compared with the comparative example 1; The total aroma component content of the tobacco leaves baked by the present application embodiment 2 is as high as 393.38 μg / g, which is increased by 28.21 μg / g compared with the comparative example 1, and is increased by about 7.73%; the increase in key aroma components is particularly significant: neophytadiene is increased by about 8.70% compared with the comparative example 1, β-damascenone is increased by about 51.87% compared with the comparative example 1, dihydrojasmone is increased by about 41.96% compared with the comparative example 1; cembrene 2 is increased by about 20.54% compared with the comparative example 1, phenylacetaldehyde is increased by about 24.16% compared with the comparative example 1; furfural is increased by about 8.14% compared with the comparative example 1.

[0034] Table 3 Comparison table of comprehensive evaluation of sensory evaluation quality of tobacco leaves Table 3 shows that the comprehensive evaluation score of the sensory evaluation quality of the tobacco leaves baked by the baking method of the present application embodiment 1 and embodiment 2 is obviously better than that of the tobacco leaves baked by the baking method of the comparative example 1, which is specifically shown as follows: The quality of the tobacco leaves baked by the present application embodiment 1 is good, the smoke amount is 0.1 higher than that of the baking method of the comparative example 1, the aroma is 0.6 higher than that of the baking method of the comparative example 1, the harmony is 0.2 higher than that of the baking method of the comparative example 1, the irritation is 0.3 higher than that of the baking method of the comparative example 1, the taste is 0.2 higher than that of the baking method of the comparative example 1, and the comprehensive score is 1.3 higher than that of the baking method of the comparative example 1; The quality of the tobacco leaves baked by the present application embodiment 2 is good, the smoke amount is 0.1 higher than that of the baking method of the comparative example 1, the aroma is 0.4 higher than that of the baking method of the comparative example 1, the harmony is 0.2 higher than that of the baking method of the comparative example 1, the irritation is 0.3 higher than that of the baking method of the comparative example 1, the taste is 0.2 higher than that of the baking method of the comparative example 1, and the comprehensive score is 1.1 higher than that of the baking method of the comparative example 1.

[0035] In summary, Comparative Example 1 fully proves that prolonging the 42℃ constant temperature time to 6 hours (exceeding the range of 2-4 hours of the present application) will cause the appearance quality, aroma substance synthesis and sensory evaluation quality of the cured tobacco leaves to appear overall and obvious degradation.

[0036] Comparison of the quality of the cured tobacco leaves The control group was cured according to the conventional curing method, and the quality of the cured tobacco leaves of Example 1, Example 2 and the control group was compared, and the test results are shown in Table 4.

[0037] Table 4 Comparison table of the quality of the cured tobacco leaves The ratio of medium and high grade tobacco leaves of the cured tobacco leaves of Example 1 is 6.3 percentage points higher than that of the control group, the ratio of out-of-grade tobacco leaves is 3.8 percentage points lower than that of the control group, and the average price is 1.2 yuan / kg higher than that of the control group. The curing process adopted in Example 1 of the present application can obviously improve the appearance quality of the tobacco leaves, and improve the commodity grade and economic value.

[0038] The ratio of medium and high grade tobacco leaves of the cured tobacco leaves of Example 2 is 5.2 percentage points higher than that of the control group, the ratio of out-of-grade tobacco leaves is 2.4 percentage points lower than that of the control group, and the average price is 0.9 yuan / kg higher than that of the control group. Even if there is a small fluctuation, the curing process adopted in Example 2 of the present application is still stable and superior to the conventional method in improving the appearance quality and economic benefit of the tobacco leaves.

[0039] Comparison of the main aroma components of the cured tobacco leaves The control group was cured according to the conventional curing method, and the main aroma components of the cured tobacco leaves of Example 1, Example 2 and the control group were compared, and the test results are shown in Table 5.

[0040] Table 5 Comparison table of the main aroma components of the cured tobacco leaves The content of the total aroma components of the cured tobacco leaves of Example 1 is as high as 408.77 μg / g, which is 29.31 μg / g higher than that of the control group, and is increased by about 7.72%; the increase in key aroma components is particularly significant: neophytadiene is increased by about 4.69% compared with the control group, beta-damascone is increased by about 72.19% compared with the control group, megastigmatrienone B is increased by about 27.30% compared with the control group, dihydroactinidiolide is increased by about 97.78% compared with the control group, cedrol 2 is increased by about 71.30% compared with the control group, 2,6-di-tert-butyl-p-cresol is increased by about 206.78% compared with the control group, phenylacetaldehyde is increased by about 71.43% compared with the control group, and furfural is increased by about 77.49% compared with the control group; the curing process adopted in Example 1 of the present application can comprehensively and obviously increase the content of key aroma substances in tobacco leaves; The total aroma component content of the tobacco leaf after roasting in the embodiment 2 of the present application is as high as 393.38 μg / g, which is increased by 13.92 μg / g compared with the control group, and is increased by about 3.67%; the improvement in key aroma components is particularly significant: neophytadiene is increased by about 2.14% compared with the control group, beta-damascone is increased by about 63.69% compared with the control group, massoia lactone B is increased by about 7.89% compared with the control group, dihydroactinidiolide is increased by about 76.67% compared with the control group; cedrol 2 is increased by about 93.91% compared with the control group, 2,6-di-tert-butyl-p-cresol is increased by about 123.73% compared with the control group; phenylacetaldehyde is increased by about 39.10% compared with the control group; furfural is increased by about 46.07% compared with the control group; the roasting process adopted in the embodiment 2 of the present application has stable and excellent effects in improving the aroma quality of tobacco leaves.

[0041] Comparison of sensory evaluation quality of tobacco leaves after roasting The control group is roasted according to the conventional roasting method, and the sensory evaluation quality of tobacco leaves after roasting of the embodiment 1, the embodiment 2 and the control group is compared, and the test results are shown in Table 6.

[0042] Table 6 Comparison of sensory evaluation quality of tobacco leaves after roasting The tobacco leaf after roasting in the embodiment 1 of the present application has good quality, the aroma is increased by 0.4 points compared with the roasting method of the control group, the harmony is increased by 0.2 points compared with the roasting method of the control group, the irritancy is increased by 0.1 points compared with the roasting method of the control group, the taste is increased by 0.2 points compared with the roasting method of the control group, and the comprehensive score is increased by 0.9 points compared with the roasting method of the control group, and the roasting process adopted in the embodiment 1 of the present application can obviously improve the quality of tobacco leaves.

[0043] The tobacco leaf after roasting in the embodiment 2 of the present application has good quality, the aroma is increased by 0.2 points compared with the roasting method of the control group, the harmony is increased by 0.2 points compared with the roasting method of the control group, the irritancy is increased by 0.1 points compared with the roasting method of the control group, the taste is increased by 0.2 points compared with the roasting method of the control group, and the comprehensive score is increased by 0.7 points compared with the roasting method of the control group, and the roasting process adopted in the embodiment 2 of the present application can obviously improve the quality of tobacco leaves.

[0044] The embodiment of the present application provides a kind of improved high altitude low quality tobacco curing method, for high altitude low quality tobacco after curing, high chlorophyll content, insufficient aroma, low economic benefit and other prominent problems, in yellowing middle period, introduce the step of low temperature stimulation tobacco reversion: when dry ball temperature is first raised to 42 DEG C, slowly return to 38 DEG C at 0.25 DEG C / h rate, maintain wet ball temperature 35.5 DEG C, and temperature is stabilized for 10-16 hours.This process can effectively break the physiological inertia of tobacco, activate endogenous enzyme, especially chlorophyll degradation enzyme activity, significantly promote chlorophyll degradation and aroma precursor conversion.Application results show that the curing method provided by the present application can significantly reduce the chlorophyll content and color rate of cured tobacco, increase the proportion of medium and high grade tobacco;At the same time, significantly increase key aroma components such as beta-damascone, neophytadiene, etc., sensory evaluation in aroma amount, aroma quality, coordination and taste, etc.All aspects are comprehensively improved.The method of the present application is clear in steps, simple in operation, easy to popularize, and provides an efficient and reliable technical solution for solving the problem of high altitude tobacco curing, improving tobacco quality and economic benefit.

[0045] The above description is only the preferred embodiment of the present application. Those skilled in the art should understand that the disclosed range of the present application is not limited to the technical solution formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the disclosed concept. For example, the above features are replaced with the technical features disclosed in the present application (but not limited to) having similar functions to form a technical solution.

Claims

1. A method for improving the curing of low-quality tobacco leaves grown at high altitudes, characterized in that, include: The tobacco leaves are loaded into the curing barn and then sealed and ignited. In the early stage of yellowing, the dry and wet bulb temperatures are raised from room temperature to 32°C and baked at the above dry and wet bulb temperatures for 4-6 hours; then the dry bulb temperature is raised to 35°C and the wet bulb temperature is raised to 34°C and baked at the above dry and wet bulb temperatures for 10-12 hours until the tips of the tobacco leaves in the high-temperature layer soften. In the middle of the yellowing period, the dry bulb temperature is raised to 38°C and the wet bulb temperature is raised to 35.5°C. The leaves are baked at the above dry and wet bulb temperatures for 10 hours until the tobacco leaves in the high-temperature layer are 50-60% yellow. Then the dry bulb temperature is raised to 42°C and the wet bulb temperature is maintained at 35.5°C. The leaves are baked at the above dry and wet bulb temperatures for 2-4 hours. In the later stages of yellowing, the dry-bulb temperature is reduced from 42℃ to 38℃, while the wet-bulb temperature is maintained at 35.5℃. The leaves are then baked at these temperatures for 10-16 hours until the tobacco leaves in the high-temperature layer are fully wilted, the leaf color changes from dark green to light green and yellowish, and the veins begin to soften. The dry-bulb temperature is then raised back to 42℃, while the wet-bulb temperature is maintained at 35.5℃. The leaves are then baked at these temperatures for 16-20 hours until the tobacco leaves in the high-temperature layer have green veins, yellow leaves, hooked tips, and curled edges. In the early stage of color fixation, the dry bulb temperature is raised to 48°C and the wet bulb temperature is raised to 36°C. The tobacco leaves are baked at the above dry and wet bulb temperatures for 16 to 20 hours until they reach the high temperature layer. In the later stage of color fixation, the dry bulb temperature is raised to 54℃ and the wet bulb temperature is raised to 37℃. The tobacco leaves are baked at the above dry and wet bulb temperatures for 18-20 hours until all the tobacco leaf tissue in the oven is completely dry. During the drying period, the dry bulb temperature is raised to 68℃ and the wet bulb temperature is raised to 39℃. The tobacco leaves are then baked at these temperatures for 24-36 hours until the entire tobacco barn is dry.

2. The method for improving the curing of low-quality tobacco leaves at high altitudes according to claim 1, characterized in that, During the early stage of the yellowing period, the heating rate for raising the dry bulb temperature from room temperature to 32°C is 1°C / 2h to 1°C / 4h, and the heating rate for raising the dry bulb temperature to 35°C is 1°C / h.

3. The method for improving the curing of low-quality tobacco leaves at high altitudes according to claim 1, characterized in that, During the middle of the yellowing period, the heating rate to raise the dry bulb temperature to 38°C is 1°C / 2h; the heating rate to raise the dry bulb temperature to 42°C is 1°C / 0.5h.

4. The method for improving the curing of low-quality tobacco leaves at high altitudes according to claim 1, characterized in that, During the later stages of the yellowing period, the rate at which the dry bulb temperature is reduced from 42°C to 38°C is 1°C / 0.25h, and the rate at which the dry bulb temperature is raised back to 42°C is 1°C / 2h.

5. The method for improving the curing of low-quality tobacco leaves at high altitudes according to claim 1, characterized in that, During the early stage of the color fixation period, the heating rate for raising the dry bulb temperature to 48°C is 1°C / 2h.

6. The method for improving the curing of low-quality tobacco leaves at high altitudes according to claim 1, characterized in that, During the later stage of the color fixation period, the heating rate for raising the dry bulb temperature to 54°C is 1°C / 2h.

7. The method for improving the curing of low-quality tobacco leaves at high altitudes according to claim 1, characterized in that, During the drying period, the heating rate to raise the dry bulb temperature to 68°C is 1°C / h.

8. The method for improving the curing of low-quality tobacco leaves at high altitudes according to claim 1, characterized in that, The process involves loading tobacco leaves into the curing barn, and then weaving them at a rate of 7-8 kg / pole or 10-12 kg / clamp, with a speed of 42-45 kg / m. 3 The density of the smoke is used for packing.

9. A method for improving the curing of low-quality tobacco leaves at high altitudes according to claim 8, characterized in that, The drying room is a dense drying room with descending airflow.

10. A method for improving the curing of low-quality tobacco leaves at high altitudes according to claim 8, characterized in that, The tobacco leaves include any one of K326, Honghua Dajinyuan, and Yunyan 87.

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