Method and system for detecting sugar content of cotton fiber based on visible near infrared spectrum

Abstract

The invention provides a method and system for detecting the sugar content of cotton fiber based on visible near infrared spectroscopy, and the method comprises the following steps: preparing fructose standard solutions with different concentrations, measuring the transmission spectrum of the fructose solutions with different concentrations, and calculating and correcting the absorbance of the fructose standard solutions; establishing a standard working curve taking the corrected absorbance of the fructose standard solution as a vertical coordinate and the concentration of the fructose standard solution as a horizontal coordinate; treating the cotton fiber sample, preparing a cotton fiber extract liquor, collecting the transmission spectrum of the cotton fiber extract liquor, and calculating and correcting the absorbance of the cotton fiber extract liquor; and substituting the corrected absorbance of the cotton fiber extract into the standard working curve, and predicting the sugar concentration of the cotton fiber extract to obtain the sugar content of the cotton fiber. No chemical reagent is used, so that environmental protection and no pollution are ensured; according to the method, the strong robustness of the model is ensured by utilizing visible near-infrared full-band information.

Description

Technical Field

[0001] This invention belongs to the field of cotton fiber quality detection technology in agricultural engineering, specifically relating to a method and system for detecting the sugar content of cotton fibers based on visible and near-infrared spectroscopy. Background Technology

[0002] As an economic crop, cotton's fiber quality directly impacts textile production efficiency and product quality. The sugar content in cotton fiber refers to the total amount of soluble sugars, including both endogenous and exogenous sugars. Exogenous sugars in cotton fiber are a key factor leading to abnormal fiber stickiness. Exogenous sugars (such as honeydew secreted by aphids and whiteflies) directly increase fiber stickiness, causing the "three-winding" phenomenon (sticking to the rollers, aprons, and tires) during spinning. Endogenous sugars, if not completely converted into cellulose due to factors such as frost, can also lead to chronic stickiness problems. Both reduce textile processing efficiency and affect yarn quality. It is internationally recognized that a sugar content exceeding 0.3% in raw cotton hinders the spinning process; therefore, accurate detection of cotton fiber sugar content has significant industrial value. Methods for determining cotton fiber sugar content can be categorized based on their principles, including redox titration, colorimetric methods, spectrophotometry, high-performance liquid chromatography, and near-infrared spectroscopy. Foreign expert Brushwood improved the potassium ferricyanide test method by adding an acid hydrolysis step to the standard test procedure, effectively solving the problem of insufficient sensitivity in the detection of sucrose and selenoketose. Ghosh and Roy used near-infrared technology, with the Perkins method as the quantitative basis, to determine the content of reducing sugars in cotton by grinding cotton fiber samples and using near-infrared diffuse reflectance spectroscopy. By correlating the absorbance values ​​of these wavelengths with the percentage of sugar content measured by the Perkins method, a four-wavelength (1445 nm, 1722 nm, 1905 nm, and 2230 nm) regression model was established to discuss the rapid determination of reducing sugar content using near-infrared spectroscopy for various sugars. Zhao Hailang and Han Ning et al. further separated various sugars in the extract using high-performance liquid chromatography and determined the sugar content of cotton fibers using a refractive index detector (RID). They also found that the sugars in cotton fibers were mainly fructose and glucose, with relatively low contents of other sugars.

[0003] Current methods for determining the sugar content of cotton fibers include redox titration and high-performance liquid chromatography (HPLC): although they have high quantitative accuracy, they require multiple titrations or chromatographic separations, making the operation complex and time-consuming, and HPLC equipment is expensive; traditional near-infrared spectroscopy: although the detection speed is fast, it relies on single-spectral absorbance modeling; spectrophotometry: it relies on colorimetric reactions, and can only indirectly estimate the sugar content through absorbance, and is sensitive to the detection environment (temperature, humidity), with poor repeatability, etc.

[0004] Chinese invention patent application CN105548055A discloses "a method for determining soluble sugars in cotton fibers", which is a UV-Vis spectrophotometric method using anthrone reagent as a colorimetric agent. However, although the anthrone colorimetric method optimizes the stability of the colorimetric agent, it still requires the participation of concentrated sulfuric acid, which pollutes the environment with waste liquid, and it still measures the soluble sugars in cotton fibers in a single wavelength band. Summary of the Invention

[0005] To address the aforementioned problems, the main objective of this invention is to provide a full-band detection method based on visible and near-infrared light, which addresses the issues of complex operation, high instrument costs, and the use of chemical reagents in existing cotton fiber sugar content detection methods. This method enables rapid, environmentally friendly, and easy-to-operate detection of soluble sugar content in cotton fibers.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A method for detecting sugar content in cotton fibers based on visible and near-infrared spectroscopy, comprising:

[0008] Prepare fructose standard solutions of different concentrations, measure the transmission spectra of fructose solutions of different concentrations, and calculate and correct the absorbance of fructose standard solutions.

[0009] Establish a standard working curve with the absorbance of the corrected fructose standard solution as the ordinate and the concentration of the fructose standard solution as the abscissa;

[0010] Cotton fiber samples were processed to prepare cotton fiber extract, and the transmission spectrum of the cotton fiber extract was collected. The absorbance of the cotton fiber extract was calculated and corrected.

[0011] The absorbance of the corrected cotton fiber extract was substituted into the standard working curve to predict the sugar concentration of the cotton fiber extract and obtain the sugar content of the cotton fiber.

[0012] Preferably, the transmission spectrum of the fructose standard solution is collected in the range of 350–1100 nm.

[0013] Preferably, the method for preparing the cotton fiber extract includes: weighing 2.000 g ± 0.001 g of cotton fiber sample, adding 200 mL of UR-grade purified water to the cotton fiber sample, and heating at 60 °C. The extract was shaken in a constant temperature shaker for 60 minutes and then filtered using a glass frit crucible to obtain the cotton fiber extract.

[0014] Preferably, the method for calculating and correcting the absorbance of the cotton fiber extract includes:

[0015] The transmittance of the cotton fiber extract was calculated based on the spectral values ​​measured in the cotton fiber extract, the spectral values ​​under dark conditions, and the spectral values ​​measured in a blank sample containing only UR-grade pure water.

[0016] The absorbance of the cotton fiber extract is calculated based on the transmittance of the cotton fiber extract.

[0017] The corrected absorbance is calculated based on the absorbance of the cotton fiber extract and the absorbance measured from the blank sample.

[0018] Preferably, the method for obtaining the sugar content of cotton fibers includes: calculating the sugar content of cotton fibers based on the volume of pure water used to extract the cotton fiber sample, the predicted sugar concentration of the cotton fiber extract, and the mass of the cotton fiber sample.

[0019] The present invention also provides a cotton fiber sugar content detection system based on visible and near-infrared spectroscopy, for implementing the method, comprising:

[0020] The fructose absorbance calculation module is used to prepare fructose standard solutions of different concentrations, measure the transmission spectra of fructose solutions of different concentrations, and calculate and correct the absorbance of the fructose standard solutions.

[0021] The working curve construction module is used to create a standard working curve with the absorbance of the corrected fructose standard solution as the ordinate and the concentration of the fructose standard solution as the abscissa.

[0022] The absorbance calculation module for cotton fiber extract is used to process cotton fiber samples, prepare cotton fiber extract, collect the transmission spectrum of the cotton fiber extract, and calculate and correct the absorbance of the cotton fiber extract.

[0023] The cotton fiber sugar content calculation module is used to substitute the corrected absorbance of the cotton fiber extract into the standard working curve to predict the sugar concentration of the cotton fiber extract and obtain the sugar content of the cotton fiber.

[0024] Preferably, the process for preparing the cotton fiber extract includes: weighing 2.000g ± 0.001g of cotton fiber sample, adding 200mL of UR-grade purified water to the cotton fiber sample, and heating at 60°C. The extract was shaken in a constant temperature shaker for 60 minutes and then filtered using a glass frit crucible to obtain the cotton fiber extract.

[0025] Preferably, the absorbance calculation module for cotton fiber extract includes:

[0026] The transmittance calculation unit is used to calculate the transmittance of cotton fiber extract based on the spectral values ​​measured by the cotton fiber extract, the spectral values ​​under dark conditions, and the spectral values ​​measured by the blank sample containing only UR grade pure water.

[0027] An absorbance calculation unit is used to calculate the absorbance of the cotton fiber extract based on the transmittance of the cotton fiber extract.

[0028] An absorbance correction unit is used to calculate the corrected absorbance based on the absorbance of the cotton fiber extract and the absorbance measured from the blank sample.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: by using fructose as a reagent for the standard curve, the present invention can ensure that the sugar content of cotton fibers can be detected as much as possible; the present invention does not use any chemical reagents, ensuring environmental protection and no pollution; the present invention utilizes full-band information of visible and near-infrared to ensure strong model robustness. Attached Figure Description

[0030] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the fructose solution measuring device according to an embodiment of the present invention;

[0032] Figure 2 Transmittance diagrams of fructose solutions of different concentrations according to embodiments of the present invention;

[0033] Figure 3 The above are absorbance graphs of fructose solutions of different concentrations according to embodiments of the present invention.

[0034] Figure 4 This is a normalized absorbance graph of fructose solutions of different concentrations according to an embodiment of the present invention;

[0035] Figure 5 The above are corrected absorbance graphs of fructose solutions of different concentrations according to embodiments of the present invention.

[0036] Figure 6 This is a standard working curve diagram of fructose solution according to an embodiment of the present invention;

[0037] Figure 7 This is a standard working curve diagram of the fructose solution in an embodiment of the present invention;

[0038] Figure 8 Transmittance diagrams of different cotton fiber extracts from embodiments of the present invention;

[0039] Figure 9 The above are absorbance graphs of fructose solutions of different concentrations according to embodiments of the present invention.

[0040] Figure 10 The above are corrected absorbance diagrams of different cotton fiber extracts according to embodiments of the present invention.

[0041] Figure 11This is a concentration prediction graph for different cotton fiber extracts according to an embodiment of the present invention;

[0042] Figure 12 This is a flowchart of a method according to an embodiment of the present invention.

[0043] As shown in the figure:

[0044] 1 Light source, 2 Spectrometer, 3 Fiber optic collimating coupler cuvette holder, 4 Fiber optic cable, 5 Computer. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Example 1:

[0048] like Figure 12 As shown, a method for detecting sugar content in cotton fibers based on visible and near-infrared spectroscopy is described. The reagents and instruments prepared include D-fructose, UR-grade purified water, a visible and near-infrared spectrometer (350 nm–1100 nm), and a constant-temperature oscillator (temperature control accuracy 60 ± 0.5 nm). Electronic balance (graduation value 0.001 g), glass frit crucible (G2 type), vacuum pump, 25 mL colorimetric tube, 100 mL volumetric flask, 50 mL volumetric flask, 250 mL conical flask.

[0049] D-fructose is used to prepare fructose standard solutions; a spectrometer is connected via fiber optic cable to the darkroom containing the sample and a computer to measure spectral values; a constant-temperature shaker is used to prepare cotton fiber extract; an electronic balance is used to weigh cotton fiber samples. A glass frit crucible (G2 type) and a vacuum pump are used to filter the initial cotton fiber extract. 25 mL colorimetric tubes, 100 mL volumetric flasks, 50 mL volumetric flasks, and 250 mL Erlenmeyer flasks are used to quantitatively determine the fructose solution concentration and the cotton fiber extract concentration.

[0050] Specific methods include:

[0051] S1: Prepare fructose standard solutions of different concentrations and measure the transmission spectra of fructose solutions of different concentrations, calculate and correct the absorbance of the fructose standard solutions; a further implementation method involves acquiring the transmission spectra of fructose standard solutions in the range of 350–1100 nm. The concentration gradient of the fructose standard working solution is determined as follows: prepare a series of fructose solutions of different concentrations, acquire their visible-near-infrared spectra in the range of 350–1100 nm, analyze the linear relationship between the spectral response value and the concentration, and finally determine the gradient points with concentrations of 0.04 mg / mL, 0.08 mg / mL, 0.10 mg / mL, 0.12 mg / mL, 0.16 mg / mL, and 0.20 mg / mL. This gradient has a good linear response across the entire wavelength range.

[0052] S2: Establish a standard working curve with the absorbance of the corrected fructose standard solution as the ordinate and the concentration of the fructose standard solution as the abscissa. This invention focuses on "no chemical reagents, full-band coverage, and fructose standard working curve reference," utilizing the multi-feature information advantages of the visible and near-infrared full-band (350-1100nm) spectrum, combined with fructose solution to establish a standard working curve, thus achieving the prediction of soluble sugar content. By using fructose as the reagent for the standard curve, this invention can ensure that the sugar content of cotton fibers can be detected as much as possible; this invention does not use any chemical reagents, ensuring environmental friendliness and zero pollution; this invention, by utilizing the full-band information of the visible and near-infrared spectrum, ensures the robustness of the model.

[0053] The establishment of the fructose standard curve first requires preprocessing the acquired spectral data by calculating transmittance, absorbance, and corrected absorbance using formulas. This preprocessing includes smoothing (Savitzky-Golay) and min-max normalization. Fitting is then performed using the following functional forms: linear function, quadratic polynomial, exponential function, power function, and logarithmic function. Finally, the coefficient of determination (R²) is compared. 2 The optimal fructose standard working curve is then selected by using the root mean square error (RMSE) and other parameters.

[0054] A further embodiment of the method for preparing the cotton fiber extract includes: weighing 2.000 g ± 0.001 g of cotton fiber sample, adding 200 mL of UR-grade purified water to the cotton fiber sample, and heating at 60 °C. The extract was shaken in a constant temperature shaker for 60 minutes and then filtered using a glass frit crucible to obtain the cotton fiber extract.

[0055] S3: Process cotton fiber samples, prepare cotton fiber extract, and collect the transmission spectrum of the cotton fiber extract; calculate and correct the absorbance of the cotton fiber extract; a further embodiment is that the method for calculating and correcting the absorbance of the cotton fiber extract includes:

[0056] Based on the spectral values ​​measured from the cotton fiber extract, the spectral values ​​under dark conditions, and the spectral values ​​measured from a blank sample containing only UR-grade purified water, the transmittance of the cotton fiber extract was calculated. The transmittance calculation formula is as follows:

[0057]

[0058] T sample : Spectral values ​​measured from the sample solution; T dark Spectral values ​​under dark conditions; T empty : Spectral values ​​measured from blank samples.

[0059] Calculate the absorbance of the cotton fiber extract based on its transmittance; the formula for absorbance calculation is as follows:

[0060]

[0061] The corrected absorbance is calculated based on the absorbance of the cotton fiber extract and the absorbance measured from the blank sample.

[0062] The corrected absorbance is calculated as follows:

[0063]

[0064] A C : Correct absorbance; A sample : Absorbance measured from the extract of cotton fiber sample; A empty : Absorbance measured on a blank sample.

[0065] S4: Substitute the corrected absorbance of the cotton fiber extract into the standard working curve to predict the sugar concentration of the cotton fiber extract and obtain the sugar content of the cotton fiber.

[0066] A further implementation method for obtaining the sugar content of cotton fibers includes: calculating the sugar content of cotton fibers based on the volume of pure water used to extract the cotton fiber sample, the predicted sugar concentration of the cotton fiber extract, and the mass of the cotton fiber sample. The sugar content of cotton fibers is calculated according to formula (4).

[0067] The sugar content is calculated as follows:

[0068]

[0069] X: Sugar content of the cotton fiber sample, mg / g; V: Volume of pure water used for extraction, mL (200 mL in this example); c: Concentration of the sample solution predicted by the near-infrared spectroscopy model described in this invention, mg / mL; m: Mass of the cotton fiber sample, g.

[0070] Example 2

[0071] The present invention also provides a cotton fiber sugar content detection system based on visible and near-infrared spectroscopy, for implementing the method of Example 1, comprising:

[0072] The fructose absorbance calculation module is used to prepare fructose standard solutions of different concentrations, measure the transmission spectra of fructose solutions of different concentrations, and calculate and correct the absorbance of the fructose standard solutions.

[0073] The working curve construction module is used to create a standard working curve with the absorbance of the corrected fructose standard solution as the ordinate and the concentration of the fructose standard solution as the abscissa.

[0074] The cotton fiber extract absorbance calculation module is used to process cotton fiber samples, prepare cotton fiber extracts, collect the transmission spectrum of cotton fiber extracts, and calculate and correct the absorbance of cotton fiber extracts.

[0075] The cotton fiber sugar content calculation module is used to substitute the corrected absorbance of the cotton fiber extract into the standard working curve to predict the sugar concentration of the cotton fiber extract and obtain the sugar content of the cotton fiber.

[0076] A further embodiment involves preparing the cotton fiber extract by: weighing 2.000g ± 0.001g of cotton fiber sample, adding 200mL of UR-grade purified water to the cotton fiber sample, and heating at 60°C. The extract was shaken in a constant temperature shaker for 60 minutes and then filtered using a glass frit crucible to obtain the cotton fiber extract.

[0077] A further embodiment is that the absorbance calculation module for the cotton fiber extract includes:

[0078] The transmittance calculation unit is used to calculate the transmittance of cotton fiber extract based on the spectral values ​​measured by the cotton fiber extract, the spectral values ​​under dark conditions, and the spectral values ​​measured by the blank sample containing only UR grade pure water.

[0079] The absorbance calculation unit is used to calculate the absorbance of the cotton fiber extract based on the transmittance of the extract.

[0080] The absorbance correction unit is used to calculate the corrected absorbance based on the absorbance of the cotton fiber extract and the absorbance measured from the blank sample.

[0081] Example 3

[0082] This embodiment provides specific equipment for detecting the sugar content of cotton fibers and a detailed experimental procedure.

[0083] like Figure 1 As shown, the circuit connection for spectral acquisition of the sample solution is as follows: "Light source 1 - Fiber optic 4 - Fiber optic collimating coupler mirror - Cuvette holder 3 - Fiber optic 4 - Spectrometer 2 - Data cable - Computer 5"; Figure 2 As shown, the transmittance of the spectra collected for different fructose solution concentrations was calculated using Formula 1, and then processed using Savitzky-Golay (window size 45, polynomial order 2); Figure 3 As shown, the absorbance of fructose solutions at various concentrations was calculated using Formula 2; Figure 4 As shown, the acquired absorbance image is subjected to global normalization (Min-Max value) processing; as... Figure 5 As shown, the corrected absorbance for each fructose solution concentration is calculated according to Formula 3; Figure 6 As shown, a standard working curve for fructose was fitted using linear, quadratic polynomial, exponential, power function, and logarithmic forms, with the corrected absorbance as the ordinate and different concentrations as the abscissa; (e.g.) Figure 7 As shown, select the optimal fructose standard working curve; as... Figure 8 As shown, extraction is performed on the cotton fiber solution after constant-temperature shaking; as Figure 9 As shown, the transmittance of the collected spectrum of the cotton fiber extract was calculated using Formula 1, and then processed using Savitzky-Golay (window size 45, polynomial order 2); Figure 10 As shown, the absorbance of the cotton fiber extract was calculated according to Formula 2; Figure 11 As shown, the corrected absorbance of the cotton fiber extract was calculated according to Formula 3.

[0084] The following is a specific operational example:

[0085] I. Preparation of blank solution and fructose standard solution:

[0086] 1. In this invention, 1.0 mL of (UR grade) pure aqueous solution is first pipetted into a 25 mL colorimetric tube as a blank solution;

[0087] 2. For example Figure 2 As shown, pour the blank solution into a quartz cuvette with a 10 mm optical path, place it in the calibrated 350-1100 nm range, measure the absorbance of the solution and record the readings.

[0088] 3. Weigh 0.200 g of D-fructose and place it in a 100 mL volumetric flask. Dissolve it in (UR grade) purified water and dilute to volume to obtain a standard stock solution with a concentration of 2.0 mg / mL.

[0089] 4. Using a pipette, pipette 1.0 mL, 2.0 mL, 2.5 mL, 3.0 mL, 4.0 mL, and 5.0 mL of fructose standard stock solution and inject them into 50 mL volumetric flasks respectively. Dilute to volume with (UR grade) purified aqueous solution to obtain a series of fructose standard concentrations of 0.04 mg / mL, 0.08 mg / mL, 0.10 mg / mL, 0.12 mg / mL, 0.16 mg / mL, and 0.20 mg / mL, respectively.

[0090] II. Absorbance Measurement and Curve Modeling:

[0091] 1. Transfer 1.0 mL of each fructose standard working solution into a 25 mL colorimetric tube, dilute and bring to volume to obtain a concentration gradient of 0.0016 mg / mL, 0.0032 mg / mL, 0.0040 mg / mL, 0.0048 mg / mL, 0.0064 mg / mL, and 0.0080 mg / mL. Measure the different fructose solution concentrations using the same method as in step one for measuring the blank solution.

[0092] 2. For example Figure 6 As shown, for the entire 350-1100 nm band, linear, quadratic polynomial, exponential, power function, and logarithmic functions were used respectively (y = a*x + b; y = a*x). 2 + b*x + c; y = a*exp(b*x); y = a*x b Five methods were used to establish a fructose standard curve model with corrected absorbance as the ordinate and concentration as the abscissa. This model was then analyzed using the coefficient of determination (R²). 2 The optimal fructose standard working curve was then selected by using the root mean square error (RMSE) and other parameters.

[0093] in RMSE=

[0094] R 2 A value closer to 1 indicates a better model fit, meaning a higher consistency between the predicted and actual values. A smaller RMSE indicates higher prediction accuracy and a smaller fitting error.

[0095] 3. For example Figure 7 As shown, the optimal fructose working curve quadratic polynomial is: y = 37.5533*X 2 + 0.1579*X + 0.0036(R) 2 = 0.7938, RMSE = 0.000562).

[0096] III. Preparation and Detection of Cotton Fiber Extract:

[0097] 1. Take no less than 30 g of cotton fiber samples (i.e., micronaire values ​​of 3.5, 4.0, 5.0, and 5.5) stored in a standard environment (temperature 21±1℃, relative humidity 65±2%) and weigh out 3 samples of 2.000 g ± 0.001 g each.

[0098] 2. Place each in a 250 mL Erlenmeyer flask, add 200 mL of (UR grade) pure aqueous solution to fully wet them, shake on a constant temperature shaker (60℃) for 30 min, turn the cotton over with a glass rod, and continue shaking for 30 min;

[0099] 3. For example Figure 8 As shown, three sample solutions were obtained by filtration using a glass frit crucible. 1.0 mL of each sample solution was pipetted into a 25 mL colorimetric tube, diluted, and brought to volume. The cotton fiber extract was then measured using the same method as the blank solution measurement in step one.

[0100] 4. Using the established fructose standard working curve, predict the solution concentration of the corresponding cotton fiber extract, and finally calculate the sugar content of the cotton fiber using formula 4.

[0101] 5. For example Figure 12 As shown, the predicted concentrations of cotton fiber samples in this invention are as follows: Micron value 3.5: 0.0135 mg / mL; Micron value 4.5: 0.0143 mg / mL; Micron value 5.0: 0.0151 mg / mL; Micron value 5.5: 0.0101 mg / mL.

[0102] The formula for calculating transmittance is as follows:

[0103]

[0104] T sample : Spectral values ​​measured from the sample solution; T dark Spectral values ​​under dark conditions; T empty : Spectral values ​​measured from blank samples.

[0105] Absorbance calculation formula:

[0106]

[0107] The corrected absorbance is calculated as follows:

[0108]

[0109] A C : Correct absorbance; A sample : Absorbance measured from the extract of cotton fiber sample; A empty : Absorbance measured on a blank sample.

[0110] Based on the measured corrected absorbance value, it is substituted into the fructose standard working curve model established in the previous steps to calculate the predicted concentration value of the sample solution, denoted as c, and expressed in mg / mL.

[0111] The sugar content is calculated as follows:

[0112]

[0113] X: Sugar content of the cotton fiber sample, %; V: Volume of pure water used for extraction, mL (200 mL in this example); c: Concentration of the sample solution predicted by the near-infrared spectral model described in this invention; m: Mass of the cotton fiber sample, g; K: Unit conversion factor.

[0114] The global normalization of data uses min-max normalization. Min-max normalization is a commonly used data preprocessing method that aims to linearly map the original data to a specified interval, typically [0, 1]. The formula is as follows:

[0115]

[0116] 𝑥 represents a value in the original data; min(𝑥) and max(𝑥) represent the minimum and maximum values ​​in the data set, respectively; 𝑥' is the normalized result, whose value will fall between 0 and 1.

[0117] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for detecting sugar content in cotton fibers based on visible and near-infrared spectroscopy, characterized in that, include: Prepare fructose standard solutions of different concentrations, measure the transmission spectra of fructose solutions of different concentrations, and calculate and correct the absorbance of fructose standard solutions. Establish a standard working curve with the absorbance of the corrected fructose standard solution as the ordinate and the concentration of the fructose standard solution as the abscissa; Cotton fiber samples were processed to prepare cotton fiber extract, and the transmission spectrum of the cotton fiber extract was collected. The absorbance of the cotton fiber extract was calculated and corrected. The absorbance of the corrected cotton fiber extract was substituted into the standard working curve to predict the sugar concentration of the cotton fiber extract and obtain the sugar content of the cotton fiber.

2. The method according to claim 1, characterized in that, Transmission spectra of fructose standard solutions were collected in the range of 350–1100 nm.

3. The method according to claim 1, characterized in that, The method for preparing cotton fiber extract includes: weighing 2.000 g ± 0.001 g of cotton fiber sample, adding 200 mL of UR grade purified water to the cotton fiber sample, and heating at 60 °C. The extract was shaken in a constant temperature shaker for 60 minutes and then filtered using a glass frit crucible to obtain the cotton fiber extract.

4. The method according to claim 1, characterized in that, Methods for calculating and correcting the absorbance of cotton fiber extracts include: The transmittance of the cotton fiber extract was calculated based on the spectral values ​​measured in the cotton fiber extract, the spectral values ​​under dark conditions, and the spectral values ​​measured in a blank sample containing only UR-grade pure water. The absorbance of the cotton fiber extract is calculated based on the transmittance of the cotton fiber extract. The corrected absorbance is calculated based on the absorbance of the cotton fiber extract and the absorbance measured from the blank sample.

5. The method according to claim 3, characterized in that, Methods for obtaining the sugar content of cotton fibers include: calculating the sugar content of cotton fibers based on the volume of pure water used to extract the cotton fiber sample, the predicted sugar concentration of the cotton fiber extract, and the mass of the cotton fiber sample.

6. A cotton fiber sugar content detection system based on visible and near-infrared spectroscopy, used to implement the method described in any one of claims 1-5, characterized in that, include: The fructose absorbance calculation module is used to prepare fructose standard solutions of different concentrations, measure the transmission spectra of fructose solutions of different concentrations, and calculate and correct the absorbance of the fructose standard solutions. The working curve construction module is used to create a standard working curve with the absorbance of the corrected fructose standard solution as the ordinate and the concentration of the fructose standard solution as the abscissa. The absorbance calculation module for cotton fiber extract is used to process cotton fiber samples, prepare cotton fiber extract, collect the transmission spectrum of the cotton fiber extract, and calculate and correct the absorbance of the cotton fiber extract. The cotton fiber sugar content calculation module is used to substitute the corrected absorbance of the cotton fiber extract into the standard working curve to predict the sugar concentration of the cotton fiber extract and obtain the sugar content of the cotton fiber.

7. The system according to claim 6, characterized in that, The process for preparing cotton fiber extract includes: weighing 2.000g ± 0.001g of cotton fiber sample, adding 200mL of UR-grade purified water to the cotton fiber sample, and heating at 60°C. The extract was shaken in a constant temperature shaker for 60 minutes and then filtered using a glass frit crucible to obtain the cotton fiber extract.

8. The system according to claim 7, characterized in that, The absorbance calculation module for cotton fiber extract includes: The transmittance calculation unit is used to calculate the transmittance of cotton fiber extract based on the spectral values ​​measured by the cotton fiber extract, the spectral values ​​under dark conditions, and the spectral values ​​measured by the blank sample containing only UR grade pure water. An absorbance calculation unit is used to calculate the absorbance of the cotton fiber extract based on the transmittance of the cotton fiber extract. An absorbance correction unit is used to calculate the corrected absorbance based on the absorbance of the cotton fiber extract and the absorbance measured from the blank sample.

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