Method for rapidly detecting quality of agaricus bisporus three-time fermentation compost and application thereof

Abstract

The invention discloses a method for rapidly detecting the quality of an agaricus bisporus three-time fermentation culture material and application of the method, and belongs to the technical field of biologication.The method comprises the steps that firstly, the nitrogen content, the ash content and the water content of an agaricus bisporus culture material sample are detected through a chemical method; scanning spectrum data of the agaricus bisporus culture material sample by adopting a near infrared spectrum detector; performing spectrum pretreatment on the original spectrum; establishing a nitrogen content calibration model, an ash content calibration model and a water content calibration model of the agaricus bisporus compost; then, the prediction performance of the calibration model is verified; scanning a to-be-detected agaricus bisporus three-time fermentation culture material sample by adopting a near infrared spectrum detector, and obtaining the nitrogen content, the ash content and the water content in the to-be-detected agaricus bisporus culture material sample through the nitrogen content calibration model, the ash content calibration model and the water content calibration model. The method replaces a chemical method to measure the physical and chemical indexes of the third-time material part of the agaricus bisporus, and has a better application effect.

Description

Technical Field

[0001] The invention relates to the field of biotechnology, and in particular to a method for quickly detecting the quality of a Agaricus bisporus tertiary fermentation culture medium and an application thereof. Background Art

[0002] Physical and chemical parameters such as nitrogen content, ash content and water content can be used as the most intuitive evaluation indicators of the quality of Agaricus bisporus culture medium.

[0003] Most of the tests on physiochemical parameters of Agaricus bisporus culture medium use traditional conventional chemical testing methods, which not only have few testing indicators but also take a long time (usually takes 3-7 days). They cannot timely and comprehensively evaluate the quality of the culture medium, resulting in a serious lack of quality control and supervision of the culture medium. Therefore, scientific monitoring of the quality of the culture medium is the key link to ensure increased production.

[0004] The existing near-infrared spectroscopy analysis technology introduced from abroad has the characteristics of simple operation, fast speed and non-destructiveness. However, due to the differences in domestic raw materials and temperature in different seasons, the physicochemical indicators of the culture predicted by this near-infrared spectroscopy analyzer have certain deviations and cannot be directly used to guide the production of domestic Agaricus bisporus culture materials.

[0005] However, there are few reports on the construction and application of near-infrared spectroscopy detection models for physicochemical indicators of Agaricus bisporus culture materials in China. Therefore, the establishment of near-infrared spectroscopy detection technology for Agaricus bisporus culture materials is urgently needed for the current industrial development. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a method for quickly detecting the quality of Agaricus bisporus tertiary fermentation culture medium and its application.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] The method for rapidly detecting the quality of Agaricus bisporus tertiary fermentation culture medium comprises the following steps:

[0009] 1. Use chemical method to detect nitrogen content, ash content and water content of Agaricus bisporus culture medium samples, and repeat the test at least three times for each sample;

[0010] 2. Scan the spectrum data of the Agaricus bisporus culture medium sample using a near-infrared spectrometer, repeat the process at least three times for each sample, and obtain an average spectrum, which is the original spectrum of the Agaricus bisporus culture medium sample;

[0011] 3. Perform spectral preprocessing on the original spectrum;

[0012] 4. Establish the nitrogen content calibration model, ash content calibration model and water content calibration model of Agaricus bisporus culture medium;

[0013] A calibration model with a low cross-validation standard deviation SECV and a high cross-validation correlation coefficient 1-VR is selected; specifically, WinISIⅢ near-infrared calibration software is used to calibrate using an improved least square method, and the nitrogen content, ash content and water content chemical analysis values ​​of Agaricus bisporus culture medium and the processed spectral data are linearly fitted one by one to obtain a calibration model; wherein, the spectral data is subjected to a scattering-free process + a first-order derivative process to obtain a nitrogen content calibration model; the spectral data is subjected to a standard normalization process + a first-order derivative process to obtain an ash content calibration model; the spectral data is subjected to a descattering process + a first-order derivative process to obtain a water content calibration model;

[0014] 5. Verify the prediction performance of the nitrogen content calibration model, ash content calibration model and moisture content calibration model;

[0015] 6. Use a near-infrared spectrometer to scan the Agaricus bisporus tertiary fermentation culture medium sample to be tested, and obtain the nitrogen content, ash content and water content in the Agaricus bisporus culture medium sample to be tested through a nitrogen content calibration model, an ash calibration model and a water content calibration model.

[0016] Furthermore, in step 3, standard normalization + trend change method and first-order derivative were selected to process the original spectrum.

[0017] Furthermore, in step three, the processed spectra are scanned for data matrix and chemical analysis value scores, and the Mahalanobis distance GH is calculated, and samples with GH>3 are considered abnormal samples and are eliminated.

[0018] Furthermore, the Agaricus bisporus culture medium samples were divided into a validation set of samples and a calibration set of samples.

[0019] Furthermore, near infrared spectroscopy is performed on the calibration set samples to obtain spectral data, and after preprocessing the spectral data, an improved least squares method is used to establish a calibration model for the nitrogen content, ash content and water content of Agaricus bisporus culture medium.

[0020] Furthermore, the validation set samples are used to validate the nitrogen content, ash content and moisture content calibration model of Agaricus bisporus culture medium; the validation indicators are: one or more of system deviation, prediction standard deviation, chemical analysis value standard deviation and near infrared prediction value standard deviation.

[0021] Furthermore, a near-infrared spectrometer was used to measure the Agaricus bisporus culture medium sample, with a scanning range of 850-2498nm wavelength.

[0022] Furthermore, among the validation indicators, the system deviation was less than 0.6 times of the SECV of the calibration model, the prediction standard deviation was less than 1.3 times of the SECV of the calibration model, and the difference between the standard deviation of the chemical analysis value and the standard deviation of the near-infrared prediction value was less than 20% of the standard deviation of the chemical analysis value, indicating that the prediction performance of the calibration model was reliable.

[0023] Furthermore, in step five, statistical analysis software is further used to determine the reliability of the model, and a paired t-test is performed between the chemical analysis values ​​of nitrogen content, ash content and water content of the Agaricus bisporus culture medium and the model prediction values.

[0024] In order to better achieve the purpose of the present invention, the present invention also provides an application of the method described in improving the detection efficiency of nitrogen content, ash content and / or water content in Agaricus bisporus culture material.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention constructs a set of nitrogen content calibration models, ash content calibration models and water content calibration models for online detection of the quality of Agaricus bisporus tertiary fermentation culture materials with high efficiency, fast speed and simple operation. The result monitoring of the calibration model shows that it has high accuracy and good stability, and can replace chemical methods to determine some physical and chemical indicators of Agaricus bisporus tertiary fermentation materials, and has good application effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 The original near-infrared spectrum of the key physical and chemical indicators of Agaricus bisporus culture medium;

[0029] Figure 2 This is the near infrared spectrum after standard normalization and first-order derivative processing;

[0030] Figure 3 It is a three-dimensional display diagram of the key physical and chemical indicators of Agaricus bisporus culture medium GH;

[0031] Figure 4 Calibrate the model test results for nitrogen content;

[0032] Figure 5 Calibrate the model test results for ash content;

[0033] Figure 6 Calibration model test results for water content. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0035] The test materials are 332 samples of Agaricus bisporus fermented culture materials from Shanghai Lianzhong Edible Fungi Cooperative for three years, and the near infrared spectroscopy sample set is divided into a calibration set and a validation 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, 272 samples were selected as the calibration set and 60 samples were selected as the validation set.

[0036] 1. Using chemical methods to detect key physical and chemical indicators of Agaricus bisporus culture medium

[0037] The nitrogen content, ash content and water content of 332 samples of Agaricus bisporus fermentation culture medium collected were measured by conventional chemical detection methods, with each sample repeated 3 times.

[0038] Nitrogen content measurement: crush the sample dried to constant weight, take 1g of sample, a nitrogen determination tablet and 12ml of concentrated sulfuric acid and put them into a digestion tube, and put the digestion tube into a graphite digester for digestion. Put the digested sample into the nitrogen determination instrument, input the sample weight, start distillation, and read the nitrogen content directly after the titration is completed.

[0039] Ash content measurement: Take a constant weight crucible, weigh its weight and record it as W0 (g), accurately weigh 2g of the dried sample to be tested and put it into the crucible, the total weight is recorded as W1, put the crucible containing the sample to be tested into a muffle furnace, set the temperature to 600℃, take it out after 4-5h (until the mass no longer changes), cool it, weigh its weight and record it as W2, ash content = (W1-W2) / (W1-W0)×100%.

[0040] Water content measurement: Take an empty constant weight crucible, weigh its weight and record it as M0 (g), accurately weigh 10g of the dried sample to be tested and put it into the crucible, the total weight is recorded as M1, put the crucible containing the sample to be tested into a muffle furnace, take it out, cool it, weigh its weight and record it as M2, water content = (M1-M2) / (M1-M0)×100%.

[0041] The statistical parameters of chemical analysis values ​​are shown in Table 1. The nitrogen content of the calibration set ranges from 1.50 to 2.48, with an average value of 1.94 and a standard deviation of 0.19; the ash content ranges from 23.6 to 47.5, with an average value of 37.53 and a standard deviation of 4.16; the moisture content ranges from 55.3 to 69.0, with an average value of 61.83 and a standard deviation of 2.79. The calibration set samples have a wide distribution range and are representative; the validation set is to select samples with stable chemical analysis values ​​and are within the calibration set range to ensure that the model has certain practical value.

[0042] Table 1 Statistical parameters of chemical analysis values ​​of physiochemical indicators of Agaricus bisporus culture

[0043]

[0044] 2. Collection of near infrared spectra of Agaricus bisporus culture medium samples

[0045] According to Table 1, 60 samples with relatively stable physical and chemical indicators were selected from the 332 samples used for near-infrared spectrum collection as the validation set, and the remaining 272 samples were used as the calibration set. The fresh base samples of Agaricus bisporus culture medium were mixed, and the 272 calibration set samples were measured using the NIRSTM DS2500F near-infrared spectrometer, and the near-infrared original spectrum data with a wavelength of 850-2498nm were collected, as shown in Figure 1. Figure 1 As shown in the figure, each sample was scanned 8 times to obtain an average spectrum, which is the original spectrum of the Agaricus bisporus culture medium sample. The spectra of the 272 Agaricus bisporus culture medium samples have multiple absorption peaks and the change trends are basically the same, indicating that the basic components of the culture medium are relatively consistent.

[0046] 3. Pretreatment of near infrared spectrum of Agaricus bisporus culture medium samples

[0047] 272 calibration spectrum files were opened by WinISIⅢ near-infrared calibration software, and the chemical detection values ​​corresponding to nitrogen content, ash content and water content were input. In order to eliminate or reduce the interference of useless information factors in the near-infrared spectrum and improve the accuracy of the calibration model, it is necessary to perform spectral preprocessing on the original spectrum before modeling. In the present invention, standard normalization + trend change method (SNV+DET) and derivative processing (first-order derivative processing) were selected for the original spectrum, and the results are as follows: Figure 2 The processed spectra were scanned for data matrix and chemical analysis values ​​to calculate scores, and the Mahalanobis distance GH was calculated using the score of each Agaricus bisporus culture medium sample and the average score of the calibration culture medium sample. Samples with GH>3 were considered abnormal samples and were eliminated.

[0048] Depend on Figure 3 It can be seen that most of the three-dimensional scores of physiochemical indicators in Agaricus bisporus culture are relatively concentrated, and a small number are distributed on the edge. The reason for the analysis may be that there are certain errors in the measurement of chemical analysis values.

[0049] 4. Establishment of near infrared model for key physical and chemical parameters of Agaricus bisporus culture medium and selection of optimal model

[0050] The most commonly used calibration technology for near-infrared calibration of natural samples is modified least squares (Modified PLS). The calibration model of nitrogen content, ash content and moisture content of Agaricus bisporus culture medium was established using the entire spectral band (wavelength 856-2498nm) through WinISIⅢ near-infrared calibration software, and different scattering methods and mathematical methods were used to process the spectral data. That is, standard normalization + scattering processing, no scattering processing, standard normalization processing, and de-scattering processing were used for scattering processing; the mathematical method used first-order derivative processing or second-order derivative processing, and third-order or fourth-order derivative processing would lead to the over-adaptability problem of the model. The influence of different scattering methods and mathematical methods on the calibration model was evaluated, and the best calibration method and model were selected, that is, the average value of the cross-validation standard deviation (SECV) between the near-infrared predicted value and the chemical analysis value of the samples not involved in the calibration and the average value of the cross-validation correlation coefficient (1-VR) between the near-infrared predicted value and the chemical analysis value of the samples not involved in the calibration were used to judge. SECV is the standard deviation between the near-infrared prediction value and the chemical analysis value obtained during cross-validation. SEVC can be used to roughly evaluate the prediction accuracy of the calibration model. 1-VR is the percentage of the model that can describe the concentration changes of the variety set during cross-validation. The lower the SECV, the higher the 1-VR, which means that the calibration model is better.

[0051] The calibration model was obtained by linear fitting the chemical analysis values ​​of nitrogen, ash and moisture content of Agaricus bisporus culture medium and the processed spectral data one by one.

[0052] It can be seen from Table 2 that the best model for nitrogen content is the model obtained by no scattering treatment + first-order derivative treatment (SECV = 0.0839, 1-VR = 0.8060), the best model for ash content is the model obtained by standard normalization treatment + first-order derivative treatment (SECV = 1.8991, 1-VR = 0.7851), and the best model for moisture content is the model obtained by descattering treatment + first-order derivative treatment (SECV = 1.2902, 1-VR = 0.7797).

[0053] Table 2 Main evaluation parameters of key physical and chemical indicators of Agaricus bisporus culture medium under different treatment methods

[0054]

[0055]

[0056] 5. Monitoring of key physical and chemical indicators of Agaricus bisporus culture medium using near infrared model

[0057] The prediction performance of the best calibration model was verified by using 60 independent sample groups that did not participate in the calibration (i.e., validation set samples). The system deviation (Bias) was less than 0.6 times the SECV of the calibration model, the standard deviation of prediction (SEP) was less than 1.3 times the SECV of the calibration model, and the difference between the standard deviation (SD) of the chemical analysis value and the standard deviation (SD) of the near-infrared prediction value was less than 20% of the standard deviation (SD) of the chemical analysis value, indicating that the prediction performance of the calibration model was reliable. RSQ represents the correlation coefficient between the near-infrared prediction value and the chemical analysis value of the calibration model. At the same time, the SPSS22.0 software was used to perform a paired t-test on the true value of the validation set and the model prediction value to further determine the reliability of the model.

[0058] The results of the nitrogen content calibration model test ( Figure 4 ) shows that Bias = 0.017 < 0.0839 (SECV) × 0.6 = 0.05, SEP = 0.102 < 0.0839 (SECV) × 1.3 = 0.109, 0.141 (SD) - 0.091 (SD) = 0.05 > 0.141 (SD) × 0.2 = 0.0282, RSQ (external) is 0.488.

[0059] Ash calibration model test results ( Figure 5 ) shows that Bias = 0.327 < 1.8991 (SECV) × 0.6 = 1.1395, SEP = 1.574 < 1.8991 (SECV) × 1.3 = 2.4688, 2.346-2.776 = -0.43 < 2.379 × 0.2 = 0.4758, and RSQ (external) is 0.688.

[0060] Water content calibration model test results ( Figure 6 ) shows that Bias = -0.313 < 1.2902 (SECV) × 0.6 = 0.7741, SEP = 1.828 > 1.2902 (SECV) × 1.3 = 1.6773, 2.272-1.826 = 0.446 < 2.27 × 0.2 = 0.454, RSQ (external) is 0.392.

[0061] As shown in Table 3, the P values ​​of the chemical analysis values ​​of nitrogen content, ash content and moisture content of the validation set samples and the predicted values ​​were 0.208, 0.108 and 0.187, respectively, which were not significant, further indicating that the established prediction model can well predict the nitrogen content, ash content and moisture content in unknown samples.

[0062] Table 3 t-test results of chemical analysis values ​​and predicted values ​​of validation set samples

[0063]

[0064]

[0065] In summary, the present invention has constructed a set of nitrogen content calibration models, ash content calibration models and water content calibration models for online detection of the quality of Agaricus bisporus tertiary fermentation culture materials with high efficiency, fast speed and simple operation. The result monitoring of the calibration model shows that it has high accuracy and good stability, and can replace chemical methods to determine some physical and chemical indicators of Agaricus bisporus tertiary fermentation materials, and has a good application effect.

[0066] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for rapidly detecting the quality of Agaricus bisporus tertiary fermentation culture medium, characterized in that: The following steps are involved:

1. Use chemical method to detect nitrogen content, ash content and water content of Agaricus bisporus culture medium samples, and repeat the test at least three times for each sample; 2. Scan the spectrum data of the Agaricus bisporus culture medium sample using a near-infrared spectrometer, repeat the process at least three times for each sample, and obtain an average spectrum, which is the original spectrum of the Agaricus bisporus culture medium sample; 3. Perform spectral preprocessing on the original spectrum; 4. Establish the nitrogen content calibration model, ash content calibration model and water content calibration model of Agaricus bisporus culture medium; A calibration model with a low cross-validation standard deviation SECV and a high cross-validation correlation coefficient 1-VR is selected; specifically, WinISIⅢ near-infrared calibration software is used to calibrate using an improved least square method, and the nitrogen content, ash content and water content chemical analysis values ​​of Agaricus bisporus culture medium and the processed spectral data are linearly fitted one by one to obtain a calibration model; wherein, the spectral data is subjected to a scattering-free process + a first-order derivative process to obtain a nitrogen content calibration model; the spectral data is subjected to a standard normalization process + a first-order derivative process to obtain an ash content calibration model; the spectral data is subjected to a descattering process + a first-order derivative process to obtain a water content calibration model; 5. Verify the prediction performance of the nitrogen content calibration model, ash content calibration model and moisture content calibration model; 6. Use a near-infrared spectrometer to scan the Agaricus bisporus tertiary fermentation culture medium sample to be tested, and obtain the nitrogen content, ash content and water content in the Agaricus bisporus culture medium sample to be tested through a nitrogen content calibration model, an ash calibration model and a water content calibration model.

2. The method for rapidly detecting the quality of Agaricus bisporus tertiary fermentation culture medium according to claim 1, characterized in that: In step 3, standard normalization + trend change method and first-order derivative were selected to process the original spectrum.

3. The method for rapidly detecting the quality of Agaricus bisporus tertiary fermentation culture medium according to claim 2, characterized in that: In step three, the processed spectra are scanned for data matrix and chemical analysis value scores, and the Mahalanobis distance GH is calculated. Samples with GH>3 are considered abnormal samples and are eliminated.

4. The method for rapidly detecting the quality of Agaricus bisporus tertiary fermentation culture medium according to claim 3, characterized in that: The Agaricus bisporus culture medium samples were divided into validation set samples and calibration set samples.

5. The method for rapidly detecting the quality of Agaricus bisporus tertiary fermentation culture medium according to claim 4, characterized in that: Near infrared spectroscopy is performed on the calibration set samples to obtain spectral data, and after preprocessing the spectral data, an improved least square method is used to establish a calibration model for the nitrogen content, ash content and water content of Agaricus bisporus culture medium.

6. The method for rapidly detecting the quality of Agaricus bisporus tertiary fermentation culture medium according to claim 5, characterized in that: The validation set samples are used to validate the nitrogen content, ash content and water content calibration model of Agaricus bisporus culture medium; the validation indexes are: one or more of system deviation, prediction standard deviation, chemical analysis value standard deviation and near infrared prediction value standard deviation.

7. The method for rapidly detecting the quality of Agaricus bisporus tertiary fermentation culture medium according to claim 6, characterized in that: The Agaricus bisporus culture medium samples were measured using a near-infrared spectrometer with a scanning range of 850-2498 nm wavelength.

8. The method for rapidly detecting the quality of Agaricus bisporus tertiary fermentation culture medium according to claim 7, characterized in that: Among the validation indicators, the system deviation is less than 0.6 times of the SECV of the calibration model, the prediction standard deviation is less than 1.3 times of the SECV of the calibration model, and the difference between the standard deviation of the chemical analysis value and the standard deviation of the near-infrared prediction value is less than 20% of the standard deviation of the chemical analysis value, indicating that the prediction performance of the calibration model is reliable.

9. The method for rapidly detecting the quality of Agaricus bisporus tertiary fermentation culture medium according to claim 8, characterized in that: In step five, statistical analysis software was used to determine the reliability of the model, and paired t-tests were performed on the chemical analysis values ​​of nitrogen content, ash content, and water content of the Agaricus bisporus culture medium and the model prediction values.

10. A method according to any one of claims 1 to 9 for detecting nitrogen content, ash content and water content in Agaricus bisporus culture medium.

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