Method for predicting moisture of re-dried tobacco stems

Abstract

The invention discloses a method for predicting moisture of redried tobacco stems. The method comprises the following steps: preparing a sample; initial moisture detection; simulating re-drying: dividing the balanced samples in different production areas into a plurality of parts, and respectively drying at different temperatures; moisture detection: detecting the instant moisture content of the samples in different production areas at different temperatures at different time points; and model prediction: establishing a water loss equation based on a Weibull model according to the instant water content of the balanced sample at different time points at different temperatures in different production areas, and predicting the instant water content of the sample by using the water loss equation. According to the method for predicting the moisture of the re-dried tobacco stems, the water loss equation based on the Weibull model is used for predicting the instant moisture content of balanced samples in different production areas at different temperatures, a basis is provided for controlling the stability of the moisture content of tobacco stem processing, and technical support is provided for classified processing of the tobacco stems and improvement of the processing quality of cut stems.

Description

Technical Field

[0001] The present invention relates to the technical field of tobacco stem moisture prediction, and more particularly, to a method for predicting the moisture content of redrying tobacco stems. Background Art

[0002] Cut stems offer the advantages of low cost and high filling value, significantly reducing the tar content of cigarette smoke and are widely used in tobacco product formulations. Studies have shown that the physical properties and chemical composition (such as total sugar, total nitrogen, and nicotine) of tobacco stems vary significantly from region to region, leading to differences in their water retention capacity. Moisture control during tobacco stem storage is a key factor in preventing mold. Based on tobacco industry experience and relevant research (such as "YC / T 146-2010 Tobacco Stems"), the moisture content of tobacco stems is generally controlled within the range of 10% to 12%. Within this range, the water activity (Aw) of tobacco stems is low, effectively inhibiting the growth and reproduction of molds (such as Aspergillus and Penicillium), significantly reducing the risk of mold. Too high or too low a moisture content in tobacco stems will have adverse effects. If the moisture content exceeds 13%, the risk of mold growth increases sharply, especially in an environment with a temperature above 25°C or high humidity, where mold may occur within a few days. If the moisture content is below 8%, the tobacco stems may become brittle and fragile, affecting the quality of subsequent processing (such as the production of reconstituted tobacco leaves). It is necessary to balance the requirements of mold prevention and physical properties.

[0003] Tobacco stems are produced directly during the threshing and redrying process. This process involves separating the tobacco leaves from the stems after threshing, and then redrying them to control moisture and maintain quality. The moisture content of redrying tobacco stems directly affects storage stability and subsequent processing. According to "YC / T 146-2010 Tobacco Stems," the threshing and redrying process specification, the factory moisture content of redrying tobacco stems is generally set at 12% ± 1% (i.e., 11% to 13%). The specific value may be adjusted based on the company's processes or customer needs. The moisture content of redrying tobacco stems is generally controlled within this range to effectively inhibit mold growth (water activity Aw ≤ 0.7), maintain stem toughness, avoid brittleness caused by overdrying, and ensure suitable physical properties for subsequent processing (such as silk making and reconstituted tobacco leaves).

[0004] Tobacco stems from different regions exhibit significant differences in drying properties, primarily influenced by factors such as raw material characteristics, climatic conditions, processing technology, and storage environment. Regarding raw material characteristics, tobacco stems from high-latitude regions (such as Northeast China and the Yunnan-Guizhou Plateau) are thicker, have a higher fiber content, a dense structure, and a slower water evaporation rate. Tobacco stems from low-latitude regions (such as South China and Southeast Asia) are thinner, have a thinner skin, and are higher in pectin and sugar, making them prone to clumping during drying. Due to the varying drying properties of tobacco stems from different regions, tobacco stems processed using the same pretreatment parameters can have significantly different moisture contents after storage, making it difficult to ensure moisture stability in subsequent processing steps, which in turn affects the quality of cut stems. However, research on the water loss properties of tobacco stems from different regions has been scarce.

[0005] Therefore, there is an urgent need for a method to predict the moisture content of tobacco stems after redrying. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for predicting the moisture content of tobacco stems after redrying, so as to solve the problems in the above-mentioned prior art and to predict the instantaneous moisture content of equilibrated samples at different temperatures in different production areas.

[0007] The present invention provides a method for predicting the moisture content of tobacco stems after redrying, which comprises:

[0008] Sample preparation: Tobacco stem samples from different production areas are collected and sieved to obtain tobacco stems of different coarseness and fineness. The sieved samples are then equilibrated according to the sieving ratio to obtain equilibrated samples.

[0009] Initial moisture test: Take the balanced sample and use the oven method to test the moisture content to obtain the initial moisture content of the sample;

[0010] Simulated redrying: The balanced samples from different production areas are divided into multiple portions and dried at different temperatures;

[0011] Moisture detection: After equilibration, samples are taken from different production areas and temperatures, and the instantaneous moisture content is detected at different time points.

[0012] Model prediction: Based on the instantaneous moisture content of the equilibrated samples at different temperatures in different production areas at different time points, a water loss equation based on the Weibull model is established, and the water loss equation is used to predict the instantaneous moisture content of the equilibrated samples at different temperatures in different production areas.

[0013] In the above method for predicting the moisture content of tobacco stems after redrying, preferably, the sample preparation comprises: taking tobacco stem samples from different production areas, sieving the tobacco stem samples to obtain tobacco stems of different coarseness and fineness, taking the sieved samples according to the sieving ratio and performing balancing treatment to obtain balanced samples, including:

[0014] Tobacco stem samples from different production areas were collected and sieved using a tobacco stem sieving device to obtain stem tips, thin stems, and medium stems. The diameter of the stem tips was greater than 16 mm, the diameter of the thin stems was less than 3 mm, and the diameter of the medium stems was between 3 mm and 16 mm.

[0015] Take a sample of not less than 200g after sieving according to the sieving ratio of the stem, thin stem and medium stem, and separate it by quartering, taking one quarter to make a sample of not less than 50g;

[0016] The sample was balanced in a constant temperature and humidity chamber at a temperature of 65°C to 85°C and a relative humidity of 75% to 85% for 45 hours to obtain the balanced sample.

[0017] In the above method for predicting the moisture content of tobacco stems after redrying, preferably, the simulated redrying comprises: dividing the equilibrated samples from different production areas into multiple portions and subjecting each portion to drying treatment at different temperatures, including:

[0018] Set the temperature of the hot air oven to 100°C, 105°C, 110°C, 115°C, and 120°C respectively, and preheat the hot air oven for 18-22 minutes in advance;

[0019] The balanced tobacco stem samples from different production areas were divided into 15 parts and placed in hot air ovens at different temperatures. Three tobacco stem samples from different production areas were placed in the hot air oven at each temperature, and the drying time was not less than 40 minutes.

[0020] In the above method for predicting the moisture content of tobacco stems after redrying, preferably, the moisture detection comprises detecting the instantaneous moisture content at different time points of equilibrated samples at different temperatures in different production areas, including:

[0021] Every 4.9-5.1 minutes, quickly take out the sample from the oven, weigh it and record the weight, and immediately put it back into the oven to continue drying;

[0022] Calculate the instantaneous moisture content of the sample based on the initial moisture content of the sample and the mass difference between the sample at each time point and the initial sample;

[0023] If the relative mass ratio of the sample changes by ≤0.01% during the test time, the sample is considered to have reached equilibrium, and the moisture content of the sample at this time is the equilibrium moisture content of the sample under the experimental conditions;

[0024] According to the instantaneous moisture content of the sample at each time point, a curve of instantaneous moisture content changing with time is obtained.

[0025] In the above method for predicting the moisture content of tobacco stems after redrying, preferably, the model prediction comprises: establishing a water loss equation based on the Weibull model according to the instantaneous moisture content corresponding to the equilibrium samples at different temperatures in different production areas at different time points, and using the water loss equation to predict the instantaneous moisture content of the equilibrium samples at different temperatures in different production areas, including:

[0026] For the equilibrated samples from different production areas and temperatures, the water loss ratio of the samples at time t was calculated using the following formula based on the weight of the tobacco stems at each time point during the drying process:

[0027] MR= (1)

[0028] Wherein, MR represents the water loss ratio of the sample at time t; It represents the mass of the sample at time t, in g; represents the initial mass of the sample in g, Indicates the mass of the sample at equilibrium, in g;

[0029] According to the water loss ratio of the samples at different times, the Weibull model was used to fit the data, and the characteristic time parameter α and shape parameter β of the Weibull model of samples from different production areas at different temperatures were obtained. The Weibull model is shown in the following formula:

[0030] MR= (2)

[0031] Among them, t represents the dehydration time, the unit is min, α represents the characteristic time parameter of the model, the unit is min, and β represents the shape parameter of the model;

[0032] Using the obtained time parameter α and shape parameter β values ​​in the Weibull model and the initial moisture content of the samples, the moisture content determination coefficient δ of different production areas at different temperatures was calculated using the following formula:

[0033] (3)

[0034] in, Indicates the initial moisture content of the sample,

[0035] Taking drying time as the independent variable, instantaneous moisture content as the dependent variable, and the moisture content determination coefficient δ as the equation coefficient, a custom formula for nonlinear fitting was established, and the water loss equations for samples from different production areas at different temperatures were established. The water loss equations were then used to estimate the instantaneous moisture content of the samples.

[0036] In the method for predicting the moisture content of tobacco stems after redrying as described above, preferably, the custom formula for nonlinear fitting includes a power function or a logarithmic function.

[0037] The present invention provides a method for predicting the moisture content of tobacco stems after redrying. According to the instantaneous moisture content of equilibrated samples at different temperatures in different production areas at different time points, a water loss equation based on a Weibull model is established. The water loss equation is used to predict the instantaneous moisture content of the equilibrated samples at different temperatures in different production areas, thereby providing a basis for controlling the stability of the moisture content in tobacco stem processing, thereby providing technical support for tobacco stem classification processing and improving the processing quality of cut stems. The water loss characteristics of tobacco stems in different regions are analyzed in combination with Weibull model parameters, and the moisture content of tobacco stems in different time periods under different processing conditions is predicted by nonlinear model fitting. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0039] Figure 1 This is a flow chart of an embodiment of the method for predicting the moisture content of tobacco stems after redrying provided by the present invention. DETAILED DESCRIPTION

[0040] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present disclosure, its application, or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of parts and steps, the composition of materials, numerical expressions, and numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limiting.

[0041] The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are simply used to distinguish different parts. Terms such as "include" or "comprising" mean that the elements preceding the term include the elements listed after the term, and do not exclude the possibility of also including other elements. Terms such as "upper," "lower," and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0042] In the present disclosure, when a specific component is described as being located between a first component and a second component, there may or may not be an intervening component between the specific component and the first component or the second component. When a specific component is described as being connected to another component, the specific component may be directly connected to the other component without an intervening component, or may not be directly connected to the other component but have an intervening component.

[0043] All terms (including technical or scientific terms) used in this disclosure have the same meaning as those understood by one of ordinary skill in the art to which this disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in, for example, general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or highly formal sense, unless explicitly defined herein.

[0044] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0045] like Figure 1 As shown, the method for predicting the moisture content of redrying tobacco stems provided in this embodiment includes the following steps during actual implementation:

[0046] Step S1, sample preparation: tobacco stem samples are taken from different production areas, and the tobacco stem samples are sieved to obtain tobacco stems of different coarseness and fineness. The sieved samples are taken according to the sieve ratio and balanced to obtain balanced samples.

[0047] In one embodiment of the method for predicting the moisture content of tobacco stems after redrying of the present invention, step S1 may specifically include:

[0048] Step S11: Take tobacco stem samples from different production areas respectively, and use a tobacco stem screening device to screen the tobacco stem samples to obtain bends, thin stems and medium stems, wherein the diameter of the bends is greater than 16 mm, the diameter of the thin stems is less than 3 mm, and the diameter of the medium stems is 3 mm-16 mm.

[0049] Step S12: Take a sample of not less than 200 g after sieving according to the sieving ratio of the stem, thin stem and medium stem, and separate it by quartering, taking one quarter to make a sample of not less than 50 g.

[0050] Step S13: Equilibrate in a constant temperature and humidity chamber at a temperature of 65° C. to 85° C. and a relative humidity of 75% to 85% for 45 hours to 50 hours (for example, 48 hours) to obtain an equilibrium sample.

[0051] In one embodiment of the present invention, 5000 g of tobacco stems from 2024 Henan Xuchang Zhongyan 100 and 2024 Fujian Sanming Cui Bi No. 1 were randomly taken. After screening of the 2024 Henan Xuchang Zhongyan 100 sample, the proportions of thin stems, medium stems and turned stems were 19.35%, 67.95% and 12.70% respectively; after screening of the 2024 Fujian Sanming Cui Bi No. 1 sample, the proportions of thin stems, medium stems and turned stems were 21.10%, 68.78% and 10.12% respectively.

[0052] Randomly sample 20g of sieved fine stems, 140g of medium stems, and 40g of stalks from each of the 2024 Henan Xuchang Zhongyan 100 and 2024 Fujian Sanming Cuibi No. 1 varieties. Mix the mixture evenly to form a single sample, then divide the mixture into four equal parts. From one of these samples, approximately 50g, equilibrate in a constant temperature and humidity chamber at 70°C and 80% relative humidity for 48 hours. Repeat this process until 16 samples each of the 2024 Henan Xuchang Zhongyan 100 and 2024 Fujian Sanming Cuibi No. 1 varieties are obtained, for a total of 32 samples. These samples are then placed in a constant temperature and humidity chamber for equilibration.

[0053] Step S2, initial moisture detection: take the balanced sample and perform moisture detection using the oven method to obtain the initial moisture content of the sample.

[0054] In one embodiment of the present invention, one sample each of 2024 Henan Xuchang Zhongyan 100 and 2024 Fujian Sanming Cui Bi No. 1 were taken, and the initial moisture of the samples was tested using the oven method, and the initial moisture contents were found to be 21.12% and 23.98%, respectively.

[0055] Step S3, simulated redrying: the balanced samples from different production areas are divided into multiple portions and subjected to drying treatment at different temperatures.

[0056] In one embodiment of the method for predicting the moisture content of tobacco stems after redrying of the present invention, step S3 may specifically include:

[0057] Step S31 : setting the temperatures of the hot air oven to 100° C., 105° C., 110° C., 115° C., and 120° C., respectively, and preheating the hot air oven for 18 min-22 min (for example, 20 min).

[0058] Step S32: Divide the balanced tobacco stem samples from different production areas into 15 portions, and place them in hot air ovens at different temperatures. Three tobacco stem samples from different production areas are placed in the hot air oven at each temperature, and the drying time is not less than 40 minutes.

[0059] In one embodiment of the present invention, the balanced tobacco stem samples are placed in a hot air oven, the oven is preheated for 20 minutes in advance, and the temperatures are set to 100°C, 105°C, 110°C, 115°C, and 120°C, respectively. Three tobacco stem samples each of 2024 Henan Xuchang Zhongyan 100 and 2024 Fujian Sanming Cui Bi No. 1 are placed in the oven at each temperature.

[0060] Step S4, moisture detection: for the equilibrated samples at different temperatures in different production areas, the instantaneous moisture content at different time points is detected.

[0061] In one embodiment of the method for predicting the moisture content of tobacco stems after redrying of the present invention, step S4 may specifically include:

[0062] Step S41 , every 4.9 min-5.1 min (for example, 5 min), quickly take out the sample from the oven, weigh it and record the weight, and immediately put it back into the oven to continue drying.

[0063] In one embodiment of the present invention, balanced 2024 Henan Xuchang Zhongyan 100 and 2024 Fujian Sanming Cuibi No. 1 tobacco stem samples are weighed respectively, and the samples are quickly taken out, weighed and recorded at drying times of 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min and 40 min, and immediately put back and close the oven door after weighing.

[0064] Step S42: Calculate the instantaneous moisture content of the sample based on the initial moisture content of the sample and the mass difference between the sample at each time point and the initial sample.

[0065] Step S43: If the relative mass ratio of the sample changes by ≤0.01% during the test time, the sample is determined to have reached equilibrium, and the moisture content of the sample at this time is the equilibrium moisture content of the sample under the experimental conditions.

[0066] Step S44: Obtain a curve showing the change of the instantaneous moisture content over time according to the instantaneous moisture content of the sample at each time point.

[0067] The weight changes and calculated instantaneous moisture content of tobacco stems of Henan Xuchang Zhongyan 100 and Fujian Sanming Cuibi No. 1 are shown in Table 1 and Table 2 respectively.

[0068] Table 1 Weight change and instant moisture content of Henan Xuchang Zhongyan 100 tobacco stems

[0069]

[0070] Table 2 Changes in stem weight and instantaneous moisture content of Cuibi No. 1 tobacco from Sanming, Fujian

[0071]

[0072] Step S5, model prediction: Based on the instantaneous moisture content of the equilibrated samples at different temperatures in different production areas at different time points, a water loss equation based on the Weibull model is established, and the water loss equation is used to predict the instantaneous moisture content of the equilibrated samples at different temperatures in different production areas.

[0073] In one embodiment of the method for predicting the moisture content of tobacco stems after redrying of the present invention, step S5 may specifically include:

[0074] Step S51: For the equilibrated samples at different temperatures in different production areas, the water loss ratio of the samples at time t is calculated using the following formula according to the mass of the tobacco stems at each time point during the drying process:

[0075] MR= (1)

[0076] Wherein, MR represents the water loss ratio of the sample at time t; It represents the mass of the sample at time t, in g; represents the initial mass of the sample in g, Indicates the mass of the sample at equilibrium, in g.

[0077] According to formula (1), the water loss ratios (MR) of tobacco stems of Henan Xuchang Zhongyan 100 and Fujian Sanming Cuibi No. 1 are shown in Tables 3 and 4, respectively.

[0078] Table 3 Water loss ratio of tobacco stems from Henan Xuchang Zhongyan 100

[0079]

[0080] Table 4 Water loss ratio of Fujian Sanming Cuibi No. 1 tobacco stems

[0081] unit:%

[0082]

[0083] Step S52: According to the water loss ratio of the samples at different times, the data are fitted using a Weibull model to obtain the characteristic time parameter α and shape parameter β of the Weibull model for samples from different production areas at different temperatures. The Weibull model is shown in the following formula:

[0084] MR= (2)

[0085] Among them, t represents the water loss time, unit is min, α represents the characteristic time parameter of the model, unit is min, and β represents the shape parameter of the model. α can be used to describe the speed of moisture change over time. The smaller the α value, the faster the moisture change of the sample and the higher the moisture absorption rate; β can reflect the strength of the combination of moisture and tobacco stems. The larger the β value, the stronger the interaction between water molecules and tobacco stems.

[0086] Step S53: Using the obtained time parameter α and shape parameter β values ​​in the Weibull model and the initial moisture content of the samples, the coefficient of determination δ of moisture content in different production areas at different temperatures is calculated using the following formula:

[0087] (3)

[0088] in, Indicates the initial moisture content of the sample.

[0089] According to formula (2) and formula (3), the α value, β value and moisture content determination coefficient δ of Henan Xuchang Zhongyan 100 and Fujian Sanming Cuibi No. 1 are shown in Table 5.

[0090] Table 5 α value, β value and moisture content determination coefficient δ of tobacco stems from different production areas at different temperatures

[0091]

[0092] Step S54: Using 5 times the drying time (min) as the independent variable, the instantaneous moisture content as the dependent variable, and the moisture content determination coefficient δ as the equation coefficient, a custom formula for nonlinear fitting is established, and a water loss equation for samples from different production areas at different temperatures is established. The water loss equation is then used to estimate the instantaneous moisture content of the samples.

[0093] The custom formula for the nonlinear fit includes a power function or a logarithmic function (ln function), with the logarithmic function being preferred. When using the logarithmic function, the R value is closest to 1, resulting in the best fitting effect, which may be related to the water loss pattern of the stems. The water loss equations for samples from different production areas at different temperatures are shown in Table 6. In Table 6, the horizontal coordinates 1, 2, ..., 9 represent 5, 10, ..., 45 minutes, respectively. Based on Table 6, the expression for the instantaneous moisture content prediction model can be obtained. To achieve a moisture content of 12% after roasting, Henan Xuchang Zhongyan 100 tobacco stems require 13 minutes, while Fujian Sanming Cuibi No. 1 tobacco stems require 21 minutes. This time can be appropriately shortened when the redrying temperature is higher.

[0094] Table 6 Water loss equation expressions of samples from different production areas at different temperatures

[0095]

[0096] The method for predicting the moisture content of tobacco stems after redrying provided in an embodiment of the present invention establishes a water loss equation based on the Weibull model according to the instantaneous moisture content corresponding to the equilibrium samples at different temperatures in different production areas at different time points, and uses the water loss equation to predict the instantaneous moisture content of the equilibrium samples at different temperatures in different production areas, thereby providing a basis for controlling the stability of the moisture content of tobacco stem processing, and providing technical support for tobacco stem classification processing and improving the quality of stem cutting processing; the water loss characteristics of tobacco stems in different regions are analyzed in combination with the Weibull model parameters, and the moisture content of tobacco stems in different time periods under different processing conditions is predicted by nonlinear model fitting.

[0097] Thus far, various embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details known in the art have not been described. Based on the above description, those skilled in the art can fully understand how to implement the technical solutions disclosed herein.

[0098] Although some specific embodiments of the present disclosure have been described in detail through examples, those skilled in the art will understand that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. Those skilled in the art will understand that the above embodiments may be modified or some technical features may be replaced with equivalents without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A method for predicting the moisture content of tobacco stems after redrying, characterized in that: include Sample preparation: Tobacco stem samples from different production areas are collected and sieved to obtain tobacco stems of different coarseness and fineness. The sieved samples are then equilibrated according to the sieving ratio to obtain equilibrated samples. Initial moisture test: Take the balanced sample and use the oven method to test the moisture content to obtain the initial moisture content of the sample; Simulated redrying: The balanced samples from different production areas are divided into multiple portions and dried at different temperatures; Moisture detection: After equilibration, samples are taken from different production areas and temperatures, and the instantaneous moisture content is detected at different time points. Model prediction: Based on the instantaneous moisture content of the equilibrated samples at different temperatures in different production areas at different time points, a water loss equation based on the Weibull model is established, and the water loss equation is used to predict the instantaneous moisture content of the equilibrated samples at different temperatures in different production areas.

2. The method for predicting moisture content of tobacco stems after redrying according to claim 1, characterized in that: The sample preparation comprises: taking tobacco stem samples from different production areas, sieving the tobacco stem samples to obtain tobacco stems of different coarseness and fineness, taking the sieved samples according to the sieving ratio, and performing balancing treatment to obtain balanced samples, including: Tobacco stem samples from different production areas were collected and sieved using a tobacco stem sieving device to obtain stem tips, thin stems, and medium stems. The diameter of the stem tips was greater than 16 mm, the diameter of the thin stems was less than 3 mm, and the diameter of the medium stems was between 3 mm and 16 mm. Take a sample of not less than 200g after sieving according to the sieving ratio of the stem, thin stem and medium stem, and separate it by quartering, taking one quarter to make a sample of not less than 50g; The sample was balanced in a constant temperature and humidity chamber at a temperature of 65°C to 85°C and a relative humidity of 75% to 85% for 45 hours to obtain the balanced sample.

3. The method for predicting moisture content of tobacco stems after redrying according to claim 1, characterized in that: The simulated redrying process involves dividing balanced samples from different production areas into multiple portions and performing drying treatments at different temperatures, including: Set the temperature of the hot air oven to 100°C, 105°C, 110°C, 115°C, and 120°C respectively, and preheat the hot air oven for 18-22 minutes in advance; The balanced tobacco stem samples from different production areas were divided into 15 parts and placed in hot air ovens at different temperatures. Three tobacco stem samples from different production areas were placed in the hot air oven at each temperature, and the drying time was not less than 40 minutes.

4. The method for predicting moisture content of tobacco stems after redrying according to claim 1, characterized in that: The moisture detection is to detect the instantaneous moisture content of the equilibrated samples at different temperatures in different production areas at different time points, including: Every 4.9-5.1 minutes, quickly take out the sample from the oven, weigh it and record the weight, and immediately put it back into the oven to continue drying; Calculate the instantaneous moisture content of the sample based on the initial moisture content of the sample and the mass difference between the sample at each time point and the initial sample; If the relative mass ratio of the sample changes by ≤0.01% during the test time, the sample is considered to have reached equilibrium, and the moisture content of the sample at this time is the equilibrium moisture content of the sample under the experimental conditions; According to the instantaneous moisture content of the sample at each time point, a curve of instantaneous moisture content changing with time is obtained.

5. The method for predicting moisture content of tobacco stems after redrying according to claim 1, characterized in that: The model prediction: Based on the instantaneous moisture content of the samples after equilibrium at different temperatures in different production areas at different time points, a water loss equation based on the Weibull model is established, and the instantaneous moisture content of the samples after equilibrium at different temperatures in different production areas is predicted using the water loss equation, including: For the equilibrated samples from different production areas and temperatures, the water loss ratio of the samples at time t was calculated using the following formula based on the weight of the tobacco stems at each time point during the drying process: MR= (1) Wherein, MR represents the water loss ratio of the sample at time t; It represents the mass of the sample at time t, in g; represents the initial mass of the sample in g, Indicates the mass of the sample at equilibrium, in g; According to the water loss ratio of the samples at different times, the Weibull model was used to fit the data, and the characteristic time parameter α and shape parameter β of the Weibull model of samples from different production areas at different temperatures were obtained. The Weibull model is shown in the following formula: MR= (2) Among them, t represents the dehydration time, the unit is min, α represents the characteristic time parameter of the model, the unit is min, and β represents the shape parameter of the model; Using the obtained time parameter α and shape parameter β values ​​in the Weibull model and the initial moisture content of the samples, the moisture content determination coefficient δ of different production areas at different temperatures was calculated using the following formula: （3） in, Indicates the initial moisture content of the sample, Taking drying time as the independent variable, instantaneous moisture content as the dependent variable, and the moisture content determination coefficient δ as the equation coefficient, a custom formula for nonlinear fitting was established, and the water loss equations for samples from different production areas at different temperatures were established. The water loss equations were then used to estimate the instantaneous moisture content of the samples.

6. The method for predicting moisture content of tobacco stems after redrying according to claim 5, characterized in that: The custom formula for the nonlinear fitting includes a power function or a logarithmic function.

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