Method for rapidly detecting neutral detergent fiber content of feeding ramie leaves by near infrared

Abstract

The invention discloses a method for quickly detecting the content of neutral detergent fibers in feeding ramie leaves through near infrared. The method comprises the following steps: detecting the component content of the neutral detergent fibers in a feeding ramie leaf powder sample by adopting a chemical measurement method; scanning absorption spectrum data of the sample feeding ramie leaf powder by adopting a near-infrared agricultural product quality tester; selecting a spectrum pretreatment method of neutral detergent fibers; establishing a spectral analysis model by using the scanned absorption spectrum data and combining the detection value of the chemical measurement method and the data obtained by the spectrum pretreatment method; and selecting ramie leaf powder for verification feeding to correct the spectral analysis model.

Description

Technical Field

[0001] The invention belongs to the field of biotechnology, and particularly relates to a method for quickly detecting the neutral detergent fiber content of ramie leaves for feeding by near infrared. Background Art

[0002] Domestic and foreign studies have found that the tender stems and leaves of ramie for feeding are rich in crude protein, crude fiber, trace elements, amino acids and other nutrients, and can be used as high-quality protein feed. At the same time, ramie for feeding is rich in neutral detergent fiber. Neutral detergent fiber (NDF) is one of the important substrates for the production of volatile fatty acids in the rumen, which is essential for maintaining the normal function of the rumen and the health of animals. If the fiber level in the diet is low, starch fermentation is too fast, a large amount of organic acid will be produced, which will reduce the pH in the rumen, inhibit the activity of rumen microorganisms, and may cause acidosis. Therefore, it is particularly important to screen out ramie leaf germplasm with a high content of neutral detergent fiber and suitable for high-quality protein feed.

[0003] Traditionally, the 72% concentrated sulfuric acid method is commonly used to determine the content of neutral detergent fiber. The main disadvantages of this method are that it is complicated to operate, time-consuming, and cannot be carried out in large quantities. Although the high-performance liquid chromatography method for determining neutral detergent fiber is accurate, the equipment is expensive. Therefore, it is particularly important to find a method for determining the content of neutral detergent fiber quickly, accurately, efficiently, and at a low price.

[0004] Near-infrared spectroscopy analysis technology has the advantages of being fast, accurate, and pollution-free. Therefore, a near-infrared prediction model for detecting neutral detergent fiber in ramie leaves for feeding is established to shorten time and reduce costs. It can not only provide a reference for the quality evaluation of ramie for feeding as feed, but also provide a rapid screening technology for feed-type ramie germplasm. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a method for rapid near-infrared detection of the neutral detergent fiber content of ramie leaves for feeding, so as to achieve rapid and efficient detection of the neutral detergent fiber content of ramie leaves for feeding, accurately evaluate the quality of ramie feed for feeding, and provide a rapid screening technology for feed-type ramie germplasm.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The method for rapid near infrared detection of neutral detergent fiber content in ramie leaves for feeding comprises the following steps:

[0008] Step 1: using a chemical measurement method to detect the neutral detergent fiber content in the sample ramie leaf powder;

[0009] Step 2: Scan the absorption spectrum data of the sample ramie leaf powder for feeding using a near infrared agricultural product quality tester;

[0010] Step 3: Select the spectral pretreatment method for neutral detergent fiber;

[0011] Step 4: Using the scanned absorption spectrum data, combined with the detection value of the chemical measurement method and the data obtained by the spectrum preprocessing method, a spectrum analysis model is established;

[0012] Step 5: Select and verify ramie leaf powder for feeding to calibrate the spectral analysis model;

[0013] Furthermore, the determination of the neutral detergent fiber content in step 1 is repeated at least three times.

[0014] Furthermore, in step 2, an S400 near-infrared agricultural product quality measuring instrument is used to collect the absorption spectrum, and the scanning range is 1100nm to 2500nm (4000-9090.91 (1 / cm)).

[0015] Furthermore, in the step 2, the absorption spectrum of the fodder ramie leaves is scanned multiple times; and in the step 4, an infrared spectrum analysis model is established using the average value of the absorption spectrum data of the multiple scans.

[0016] Furthermore, the step 3 of selecting the spectral preprocessing method for neutral detergent fiber is to select a spectral preprocessing method that maximizes the coefficient of determination and resolution of the spectral analysis model and minimizes the correction standard deviation and relative standard deviation.

[0017] Further, the process of establishing the spectral analysis model in step 4 is as follows: using CAUNIR near-infrared calibration software, the chemical measurement value of the neutral detergent fiber content of the sample ramie leaf powder and the absorption spectrum data collected by three scans are averaged respectively, the chemical measurement value of the neutral detergent fiber content of the sample ramie leaf powder and the data after absorption spectrum pretreatment are associated one by one, and the quantitative partial least squares (QPLS) method is used for modeling. The original spectrum data preprocessing method that maximizes the determination coefficient and resolution of the spectral analysis model and minimizes the correction standard deviation and relative standard deviation is selected for data preprocessing and modeling.

[0018] Furthermore, in the step 3, the neutral detergent fiber of the ramie leaf powder for feeding is spectrally preprocessed by an external detection method, and the spectral preprocessing is performed by range normalization + standard normal transformation + scatter correction method + centralization.

[0019] Furthermore, the correlation coefficients between the neutral detergent fiber content in the ramie leaves predicted by the spectral analysis model and the actually measured neutral detergent fiber content in the ramie leaves are 0.8896.

[0020] Furthermore, in step 4, the content of neutral detergent fiber in the ramie leaves to be tested is predicted using a spectral analysis model, and the average value of the absorption spectrum data of the ramie leaf powder to be tested collected by the near-infrared agricultural product quality tester is input into the spectral analysis model. After spectral data preprocessing and model calculation and prediction, the predicted value of the component is obtained, and the content of neutral detergent fiber in the ramie leaves for feeding can be predicted.

[0021] The beneficial effect of the present invention is that the method for rapid near-infrared detection of the neutral detergent fiber content of ramie leaves for feeding is to establish a spectral analysis model by utilizing the measured neutral detergent fiber component content of sample ramie leaves for feeding, so as to achieve rapid, efficient and accurate detection of the neutral detergent fiber component content in ramie leaf powder, with low cost, and provide a rapid screening technology for feed-type ramie germplasm. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the original spectrum of the ramie leaf sample for feeding;

[0023] Figure 2 This is a correlation diagram between the measured and predicted values ​​of neutral detergent fiber of ramie for feed. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The method for rapid near infrared detection of neutral detergent fiber content in ramie leaves for feeding comprises the following steps:

[0026] Step 1: using a chemical measurement method to detect the neutral detergent fiber content in the sample ramie leaf powder;

[0027] Step 2: Scan the absorption spectrum data of the sample ramie leaf powder for feeding using a near infrared agricultural product quality tester;

[0028] Step 3: Select the spectral pretreatment method for neutral detergent fiber;

[0029] Step 4: Using the scanned absorption spectrum data, combined with the detection value of the chemical measurement method and the data obtained by the spectrum preprocessing method, a spectrum analysis model is established;

[0030] Step 5: Select and verify ramie leaf powder for feeding to calibrate the spectral analysis model;

[0031] Furthermore, the determination of the neutral detergent fiber content in step 1 is repeated at least three times.

[0032] Furthermore, in step 2, an S400 near-infrared agricultural product quality measuring instrument is used to collect the absorption spectrum, and the scanning range is 1100nm to 2500nm (4000-9090.91 (1 / cm)).

[0033] Furthermore, in the step 2, the absorption spectrum of the fodder ramie leaves is scanned multiple times; and in the step 4, an infrared spectrum analysis model is established using the average value of the absorption spectrum data of the multiple scans.

[0034] Furthermore, the step 3 of selecting the spectral preprocessing method for neutral detergent fiber is to select a spectral preprocessing method that maximizes the coefficient of determination and resolution of the spectral analysis model and minimizes the correction standard deviation and relative standard deviation.

[0035] Further, the process of establishing the spectral analysis model in step 4 is as follows: using CAUNIR near-infrared calibration software, the chemical measurement value of the neutral detergent fiber content of the sample ramie leaf powder and the absorption spectrum data collected by three scans are averaged respectively, the chemical measurement value of the neutral detergent fiber content of the sample ramie leaf powder and the data after absorption spectrum pretreatment are associated one by one, and the quantitative partial least squares (QPLS) method is used for modeling. The original spectrum data preprocessing method that maximizes the determination coefficient and resolution of the spectral analysis model and minimizes the correction standard deviation and relative standard deviation is selected for data preprocessing and modeling.

[0036] Furthermore, in the step 3, the neutral detergent fiber of the ramie leaf powder for feeding is spectrally preprocessed by an external detection method, and the spectral preprocessing is performed by range normalization + standard normal transformation + scatter correction method + centralization.

[0037] Furthermore, the correlation coefficients between the neutral detergent fiber content in the ramie leaves predicted by the spectral analysis model and the actually measured neutral detergent fiber content in the ramie leaves are 0.8896.

[0038] Furthermore, in step 4, the content of neutral detergent fiber in the ramie leaves to be tested is predicted using a spectral analysis model, and the average value of the absorption spectrum data of the ramie leaf powder to be tested collected by the near-infrared agricultural product quality tester is input into the spectral analysis model. After spectral data preprocessing and model calculation and prediction, the predicted value of the component is obtained, and the content of neutral detergent fiber in the ramie leaves for feeding can be predicted.

[0039] Example

[0040] The test materials are 195 samples of ramie leaf powder for feeding, each of which is divided into 2 groups, one for chemical composition determination and the other for near-infrared spectrum collection. The near-infrared spectrum sample set is divided into a calibration set and a test set. The calibration set is used to establish the model and the internal cross-validation of the model, and the test set is used for the external validation of the model. In this experiment, 173 samples were selected as the calibration set and 22 samples were selected as the test set.

[0041] Collection of near infrared scanning spectra:

[0042] Use a micro-plant crusher to crush, fully mix and sieve, dry at 105℃ for 24 hours, place the sample in a glass dryer, cool to room temperature, put it into a small round sample cup, scrape and compact the sample to ensure that the loaded sample is uniform, and the sample weight is about 3g. The S400 near-infrared agricultural product quality tester is used to collect the absorption spectrum, with a scanning range of 1100nm~2500nm (4000-9090.91(1 / cm)). In order to reduce the interference of instrument fluctuations and sample loading on spectral scanning, each sample is scanned 3 times, and the spectrum processing software is used to merge into an average spectrum for modeling and verification.

[0043] Neutral detergent fiber content determination

[0044] The statistical results of the calibration set and test set sample data of the near infrared model of neutral detergent fiber of ramie leaves forage are shown in Table 1. The neutral detergent fiber content of the validation set of ramie leaves forage materials ranges from 29.43% to 66.73%, with an average of 44.09%; the neutral detergent fiber content of the validation set ranges from 22.85% to 57.21%, with an average of 43.15%. The distribution range of the chemical composition content of the samples is obviously different, and the samples are representative to a certain extent.

[0045] Table 1 Determination of detergent fiber content in ramie leaves for feeding

[0046]

[0047] Collection of original spectra

[0048] Figure 1 The figure shows the near-infrared diffuse reflectance spectrum of the ramie leaf sample for feeding at 1100nm~2500nm (4000-9090.91 (1 / cm)). There are multiple absorption peaks in the full wavelength range. The absorption spectrum characteristics of different samples in the near-infrared spectrum region are basically the same, and the full spectrum shows a high and low gentle trend, indicating that the main components of the samples are basically the same, but the relative content of each component is different. The near-infrared spectrum of the sample can be used to determine the detergent fiber content in the middle washing.

[0049] Original spectrum preprocessing and model building:

[0050] There are six methods for preprocessing the original spectrum: centering, range normalization, vector correction, scatter correction, first-order derivative, and second-order derivative. The recommended principal component number methods include external detection and internal crossover. The choice of the original spectrum preprocessing method directly affects the quality of the analysis model. The quantitative partial least squares (QPLS) method was used for modeling. The larger the determination coefficient (R2) and resolution (RPD) of the constructed near-infrared prediction model, the smaller the calibration standard deviation (SEC) and relative standard deviation (RSD), and the more accurate the prediction model. The above six preprocessing methods and the two recommended principal component number methods were compared and analyzed. The results are shown in Table 2. It was found that the determination of neutral detergent fiber content in ramie leaf powder for feeding was better by external detection, and then the spectrum preprocessing effect was best by range normalization + standard normal transformation + scatter correction + centering.

[0051] Table 2 Pretreatment results of chemical components of ramie leaves for feeding

[0052]

[0053] Model building:

[0054] The model was constructed using CAUN IR software, and there was a good linear relationship between the predicted value and the measured value after correction. The correlation coefficient of neutral detergent fiber was 0.8896. This showed that the near infrared model of ramie leaf neutral detergent fiber content had good prediction accuracy and could meet the accuracy requirements in material quality analysis.

[0055] Model Validation:

[0056] 22 samples of ramie leaves for forage that were not involved in the calibration were selected to verify the established neutral detergent fiber model. The verification results are shown in Table 3. The average values ​​of the measured and predicted values ​​of neutral detergent fiber are close, which are 43.15% and 43.36% respectively, and the average difference is 0.21%. The maximum absolute error between the chemical value of neutral detergent fiber and the predicted value is 7.42%, the minimum absolute error is 0.10%, and the average absolute error is 4.36%.

[0057] Table 3 Near infrared model verification results

[0058] Serial number Sample name Chemical value (%) Predicted value (%) Absolute error (%) 1 212 41.28 42.70 1.42 2 292 up 39.94 45.78 5.84 3 292 in 39.60 39.70 0.10 4 319 out of 319 41.66 41.20 0.46 5 321 next 47.74 47.31 0.43 6 328 next 49.71 44.63 5.08 7 330 35.36 42.64 7.28 8 330 22.85 30.27 7.42 9 331 up 57.21 50.67 6.54 10 332 next 47.4 42.38 5.02 11 364 on 46.94 40.81 6.13 12 334 up 39.8 43.06 3.26 13 334 next 48.16 46.43 1.73 14 334 in 39.74 45.86 6.12 15 336 next 38.72 45.76 7.04 16 336 out of 336 51.24 45.60 5.64 17 338 next 45.39 41.60 3.79 18 355 up 41.57 38.24 3.33 19 355 51.4 51.08 0.32 20 355 36.7 41.82 5.12 21 362 up 48.85 41.69 7.16 22 362 out of 3 38.02 44.65 6.63 Mean 43.15 43.36 4.36

[0059] The prediction model is built using the predicted values ​​of optical data and the values ​​measured by chemical methods. The chemical method for detecting these indicators is done in accordance with national standards, which is time-consuming and laborious. The preliminary modeling requires obtaining the chemical values ​​of a certain amount of ramie for feeding. After the model is built, it needs to be opened in the near-infrared analysis software. The x value is the predicted value of the absorption spectrum data scanned by the near-infrared agricultural product quality tester, and y is the predicted chemical value. The prediction model is established using the real measured value to ensure the reliability of the predicted value. In practical applications, it is only necessary to use a near-infrared instrument to scan the ramie leaf powder for feeding to obtain optical data, and directly use the model to measure the content of neutral detergent fiber in the leaves, without the need for chemical methods for measurement. It is simple, fast, efficient, and saves money and effort.

[0060] For those skilled in the art, various corresponding changes and modifications can be made according to the above technical solutions and concepts, and all of these changes and modifications should be included in the protection scope of the claims of the present invention.

Claims

1. A method for rapid near-infrared detection of neutral detergent fiber content in ramie leaves for feeding, characterized in that: The method comprises the following steps: Step 1: using a chemical measurement method to detect the content of neutral detergent fiber components in the sample ramie leaf powder; Step 2: Scan the absorption spectrum data of the sample ramie leaf powder for feeding using a near infrared agricultural product quality tester; Step 3: Select the spectral pretreatment method for neutral detergent fiber; Step 4: Using the scanned absorption spectrum data, combined with the detection value of the chemical measurement method and the data obtained by the spectrum preprocessing method, a spectrum analysis model is established; Step 5: Select and verify ramie leaf powder for feeding to calibrate the spectral analysis model.

2. The method for rapid near-infrared detection of neutral detergent fiber content in ramie leaves according to claim 1, characterized in that: In step 1, the neutral detergent fiber content is determined by at least three replicates.

3. The method for rapid near-infrared detection of neutral detergent fiber content in ramie leaves according to claim 1, characterized in that: In the step 2, the absorption spectrum of the fodder ramie leaves is scanned multiple times, and the scanning range is 1100nm to 2500nm.

4. The method for rapid near-infrared detection of neutral detergent fiber content in ramie leaves according to claim 1, characterized in that: When selecting the spectral preprocessing method for neutral detergent fiber, the original spectral processing method with the smallest post-modeling correction standard deviation (SEC) and relative standard deviation (RSD) is selected.

5. The method for rapid near-infrared detection of neutral detergent fiber content in ramie leaves according to claim 1, characterized in that: In the step 4, using CAUNIR near-infrared spectroscopy analysis software, the chemical measurement value of the neutral detergent fiber content of the sample ramie leaf powder and the absorption spectrum data collected by three scans are averaged respectively, the chemical measurement value of the neutral detergent fiber content of the sample ramie leaf powder and the data after absorption spectrum pretreatment are associated one by one, and the quantitative partial least squares (QPLS) method is used for modeling; The original spectral data preprocessing method that maximizes the coefficient of determination and resolution of the spectral analysis model and minimizes the correction standard deviation and relative standard deviation is selected for data preprocessing and modeling.

6. The method for rapid near-infrared detection of neutral detergent fiber content in ramie leaves according to claim 1, characterized in that: In step 5, the neutral detergent fiber of ramie leaf powder for feeding is subjected to principal component analysis of spectral preprocessing data by external detection method, and then the spectral preprocessing data is verified by range normalization + standard normal transformation + scatter correction method + centering.

7. The method for rapid near-infrared detection of neutral detergent fiber content in ramie leaves according to claim 6, characterized in that: The correlation coefficient between the neutral detergent fiber content in the ramie leaves predicted by the spectral analysis model and the actually measured neutral detergent fiber content in the ramie leaves is 0.8896.

8. The method for rapid near-infrared detection of neutral detergent fiber content in ramie leaves according to claim 1, characterized in that: The step 4 uses a spectral analysis model to predict the content of neutral detergent fiber in the ramie leaves to be tested, which is to input the average value of the absorption spectrum data of the ramie leaf powder to be tested collected by the near-infrared agricultural product quality tester into the spectral analysis model, and obtain the predicted value of the component through spectral data preprocessing and model calculation prediction, so as to predict the content of neutral detergent fiber in the ramie leaves for feeding.

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