Fish gelatin variety distinguishing method based on combination of amino acid content analysis and stoichiometric method

Abstract

The invention relates to a fish gelatin variety distinguishing method based on amino acid content analysis combined with a stoichiometric method. The method comprises the following steps: S1, obtaining the variety and content of amino acids of a fish gelatin sample; s2, carrying out Kaiser-Meyer-Olkin and Bartlet tests, carrying out principal component analysis, and drawing a principal component analysis two-dimensional diagram; according to a distribution quadrant of a main component of a to-be-detected fish gelatin sample in the determination map, determining the type of the to-be-detected fish gelatin sample; s3, establishing a Fisher discriminant analysis function model, substituting the types and content of amino acids in the fish gelatin sample to be detected into the Fisher discriminant analysis function model, and judging the fish gelatin type with the maximum function value as the type of the fish gelatin sample to be detected. According to the method, five different fish gelatin can be quickly and accurately distinguished, a new thought is provided for research of a fish gelatin identification method, the fish gelatin identification accuracy and efficiency are improved, and powerful technical support is provided for industry supervision, quality control and consumer protection.

Description

Technical Field

[0001] The invention relates to the technical field of fish glue identification, in particular to a method for distinguishing fish glue types based on amino acid content analysis combined with chemometrics. Background Art

[0002] Fish maw (Ingluciespiscis), commonly known as fish maw, fish milt, fish belly, etc., is a precious food made from the dried maw of some fish. It is rich in nutrition, rich in collagen, various amino acids, vitamins, and various trace elements such as calcium, iron, zinc, etc., and is known for its low fat and high protein content (about 85%). As a model of medicine and food with a long history, fish maw has good health care effects, but there is no unified standard at the national level to regulate it. The fish maw market is mixed, with a wide variety of products and different price systems, and lacks a unified grade classification standard. The grading of fish maw in the market often depends on subjective factors such as fish species, fish age, storage years, appearance (such as size, thickness, color) to evaluate, resulting in large subjective errors in the classification process. The imperfection of this grading system and the huge price differences between different types of fish maws provide opportunities for unscrupulous businesses. They often mislead consumers through false labeling and passing inferior products off as good ones (such as using low-priced sea bass fish maw to impersonate yellow croaker fish maw), exacerbating market chaos.

[0003] In the field of fish maw identification, DNA barcoding technology has become the most common identification method due to its strong specificity and high sensitivity. However, it also has limitations such as unsuccessful primer amplification, difficulty in distinguishing old and poorly differentiated species, cumbersome experimental procedures, and high costs.

[0004] In recent years, amino acid combined with chemometric analysis has been widely studied in the authenticity identification, origin identification, and variety differentiation of food. Wistaff et al. used principal component analysis (PCA) and partial least squares (PLS) to establish an amino acid identification model for blood orange juice and adulterated juice. The model has the ability to distinguish most authentic and fake juices. Lee et al. used high performance liquid chromatography combined with multivariate analysis to obtain the amino acid spectrum of bird's nests in the east and west regions of Malaysia, and screened out characteristic amino acids: glycine, cysteine, tryptophan, and aspartic acid. The orthogonal partial least squares OPLS-DA model achieved a 100% accuracy rate in the origin attribution of blind samples. Wen Yaqin et al. used an amino acid analyzer to determine the amino acid composition of rapeseed honey, linden honey, and acacia honey, and combined a variety of chemometric methods to identify different varieties of honey. The three types of honey were well distinguished by the LDA discriminant model. However, the amino acid identification method for fish glue has not been reported.

[0005] In view of this, it is particularly urgent and necessary to establish a new, comprehensive and adaptable method for isinglass identification. Summary of the invention

[0006] The purpose of the present invention is to overcome the existing difficulty in identifying fish glue and provide a method for distinguishing fish glue types based on amino acid content analysis combined with chemometrics. The method uses principal component analysis to achieve preliminary identification of fish glue types. For fish glue that is difficult to identify, a discriminant equation is further established through discriminant analysis. The discriminant accuracy of all training set samples is 100%, and the discriminant accuracy of test set samples is 93.33%.

[0007] The method provided by the present invention uses 5 different types of fish glue (Zolo glue, Jinlong glue, Iceland cod glue, red fish glue, white jade glue) as test samples, and uses an amino acid analyzer to determine the content and composition of amino acids in fish glue. The differences in the amino acid content between different types of fish glue are clarified by principal component analysis and discriminant analysis, and a type discrimination model of the 5 types of fish glue is established by Fisher discriminant, which can achieve rapid and accurate discrimination of fish glue types.

[0008] The specific plan is as follows:

[0009] A method for distinguishing fish glue types based on amino acid content analysis combined with chemometrics comprises the following steps:

[0010] S1, obtaining the types and contents of amino acids of the fish glue sample to be tested, as well as the types and contents of amino acids of five test samples of Zorro glue, Jinlong glue, Icelandic cod glue, red fish glue and white jade glue;

[0011] S2, the amino acid types and contents obtained in S1, sampling suitability test and Bartlett test are carried out, and principal component analysis is carried out by verification. The principal component data of the test sample are used to draw a principal component analysis two-dimensional graph as a determination map; the type of the isinglass sample to be measured is determined according to the distribution quadrant of the principal component of the isinglass sample to be measured in the determination map;

[0012] If the verification fails, the process returns to step S1; if the type of the determined fish maw sample belongs to the five test samples and is not unique, the process proceeds to the next step;

[0013] S3, utilize the amino acid kind and content of described test sample sample, establish Fisher discriminant analysis function model, substitute the amino acid kind and content of described fish glue sample to be tested into Fisher discriminant analysis function model, and judge the fish glue kind with the maximum function value as the kind of described fish glue sample to be tested.

[0014] Furthermore, the method for obtaining the types and contents of amino acids in the sample in S1 comprises the following steps:

[0015] S11. Cut the sample into pieces with stainless steel scissors or smash it with a hammer, put it into a grinder for crushing and grinding, and then sieve it to collect the gelatin powder;

[0016] S12, accurately weigh the fish glue powder and place it in a hydrolysis bottle, add hydrochloric acid solution, then add phenol, then freeze, continuously fill with nitrogen, and seal during the nitrogen filling process; put the sealed hydrolysis bottle into a heating environment for hydrolysis, cool to room temperature after taking out; open the hydrolysis bottle, rinse the hydrolysis bottle with water, filter the hydrolyzate, accurately determine the volume, shake and mix, accurately draw the sample hydrolyzate in a test tube, blow dry with a nitrogen blower, then dissolve and remove acid with secondary water, vortex, and finally blow completely with nitrogen to dry; add sodium citrate buffer solution to the test tube, vortex and mix, draw the solution filter membrane with a syringe, transfer to a sample injection bottle, and use it as a sample determination liquid for standby on the machine; prepare a standard mixed solution of amino acids at the same time, dilute it to the corresponding concentration with the machine buffer solution, vortex and mix, as a mixed amino acid standard solution, wait for use on the machine;

[0017] S13. Use an amino acid analyzer with a sulfonic acid cationic resin chromatographic column and detection wavelengths of 440nm and 570nm. Inject the sample test solution and the mixed amino acid standard solution into the amino acid analyzer in equal amounts, calculate the ratio of peak area and concentration by the external standard method, and determine the type and content of amino acids in the sample.

[0018] Further, 0.100 g of the fish glue powder in S12 is accurately weighed to 0.001 g and placed in a hydrolysis bottle, 10 mL of 6 mol / L hydrochloric acid solution is added, and then 4 drops of phenol with a concentration of 80 wt% are added, followed by freezing for 5 min, continuous nitrogen filling for 10 min, and sealing during the nitrogen filling process; the sealed hydrolysis bottle is placed in an electric heating blast drying oven at 110°C ± 1°C for hydrolysis for 24 h, and then cooled to room temperature after being taken out; the hydrolysis bottle is opened, and water is used to rinse the mixture; Wash the hydrolysis bottle, filter the hydrolyzate, accurately determine the volume to 50mL, and oscillate to mix; accurately pipette 200uL of sample hydrolyzate into a test tube, blow dry with a nitrogen blower at 45°C, then dissolve and remove acid with 200μL of secondary water, vortex, and finally blow dry with nitrogen completely; add 1.0mL of pH=2.2 sodium citrate buffer solution to the test tube, vortex to mix, use a syringe to draw the solution through a 0.22μm filter membrane, transfer to the injection bottle, and use it as the sample measurement solution for standby use on the machine.

[0019] Further, the eluent flow rate in S13 is 30-40 mL / h; the injection volume is 15-25 μL;

[0020] Optionally, a sampling suitability test and a Bartlett test are performed in S2. When the obtained KMO is ≥ 0.6 and the significance is ≤ 0.05, it is considered to have passed the validation.

[0021] Furthermore, the principal component analysis described in S2 includes principal component analysis of the contents of 16 amino acids in 5 test samples: threonine, valine, methionine, isoleucine, leucine, phenylalanine, lysine, aspartic acid, serine, glutamic acid, glycine, alanine tyrosine, histidine, arginine, and proline, and extracting four principal components with eigenvalues ​​> 1, namely principal component 1, principal component 2, principal component 3, and principal component 4, among which glycine, alanine, arginine, and proline have the largest weights in principal component 1, principal component 2 is composed of threonine, methionine, isoleucine, lysine, aspartic acid, serine, and glutamic acid; principal component 3 is valine, leucine and histidine, and principal component 4 is phenylalanine and tyrosine.

[0022] Furthermore, the PCA two-dimensional graph of the five test samples was established using the principal component 1 and the principal component 2. In the obtained judgment graph, Icelandic cod glue was distributed in the first quadrant, Zorro glue and Jinlong glue were separated from each other and distributed in the fourth quadrant, and red fish glue and white jade glue were concentrated in the second quadrant.

[0023] Furthermore, in S3, according to the types and contents of amino acids in the test samples and the discriminant analysis method, the characteristic values ​​of the canonical discriminant function and the discriminant coefficient of the Fisher function are obtained, and then the discriminant analysis function models of the five types of fish glue are established.

[0024] Furthermore, the accuracy of the discriminant analysis function model is tested, and a training set and a test set are constructed using the test samples, respectively. The types and contents of amino acids in the training set and the test set are determined, respectively, to obtain training set data and test set data; the training set data is substituted back into the discriminant analysis function model discriminant for calculation, and the test set data is tested at the same time.

[0025] The present invention also protects a terminal device for distinguishing fish glue types based on amino acid content analysis combined with chemical metrology, including a processor, a memory, and a computer program stored in the memory and running on the processor, and the processor implements the steps of the method when executing the computer program.

[0026] The present invention also protects a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method are implemented.

[0027] Beneficial effects: The present invention uses an amino acid analyzer to determine the composition and content of 16 amino acids in five types of fish glue, namely, Zolo glue, Jinlong glue, Icelandic cod glue, red fish glue, and white jade glue, and evaluates the nutritional value of fish glue by an amino acid ratio coefficient method. It is found that fish glue is rich in amino acids, high in flavor amino acids and medicinal amino acids, and has a delicious taste.

[0028] Furthermore, the present invention evaluates the essential amino acid content in fish maw according to the WHO / FAO standard model spectrum and finds that its composition ratio is not good enough and it should not be used as the main protein source food in daily life and needs to be consumed together with other foods.

[0029] Furthermore, the method provided by the present invention performs principal component analysis, and the results obtained indicate that there are differences in the amino acid content between the fish maws. The principal component analysis two-dimensional graph established based on this can be used as a determination graph; based on the distribution quadrant of the principal component of the fish maw sample to be tested in the determination graph, the type of the fish maw sample to be tested can be preliminarily determined.

[0030] For cluster samples that are difficult to identify using the discriminant graph, a discriminant equation can be established in combination with discriminant analysis to identify the type of fish maw based on the discrimination model. It has been verified that the discrimination accuracy of the discrimination model for all training set samples is 100%, and the discrimination accuracy for the test set samples is 93.33%, indicating that the model can accurately distinguish different types of fish maw. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings will be briefly introduced below. Obviously, the accompanying drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0032] Figure 1 This is a standard sample spectrum provided by an embodiment of the present invention; the meanings of the numbers in the figure are: 1. Aspartic acid Asp 2. Threonine Thr 3. Serine Ser 4. Glutamic acid Glu 5. Proline Pro 6. Glycine Gly 7. Alanine Ala 8. Cystine Asp 9. Valine Val 10. Methionine Met 11. Isoleucine Iso 12. Leucine Leu 13. Tyrosine Tyr 14. Phenylalanine Phe 15. Histidine His 16. Lysine Lys 17. Amm 18. Arginine Arg;

[0033] Figure 2 The present invention provides an amino acid spectrum of white jade glue; the meanings of the symbols in the figure are: 1. Aspartic acid Asp 2. Threonine Thr 3. Serine Ser 4. Glutamic acid Glu 5. Proline Pro 6. Glycine Gly 7. Alanine Ala 8. Cystine Asp 9. Valine Val 10. Methionine Met 11. Isoleucine Iso 12. Leucine Leu 13. Tyrosine Tyr 14. Phenylalanine Phe 15. Histidine His 16. Lysine Lys 17. Amm 18. Arginine Arg;

[0034] Figure 3It is a PCA two-dimensional graph of 5 kinds of fish glue provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0035] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. In the examples, those without specifying specific techniques or conditions are carried out according to the techniques or conditions described in the literature in this area or according to the product specification. Those without specifying the manufacturer of reagents or instruments used are all conventional products that can be obtained commercially. In the following examples, if not clearly stated, "%" refers to weight percentage.

[0036] Embodiment 1

[0037] A method for distinguishing fish glue types based on amino acid content analysis combined with chemometrics comprises the following steps:

[0038] S1. Obtain the types and contents of amino acids of the fish glue sample to be tested, as well as the types and contents of amino acids of five test samples, namely, Zorro glue, Jinlong glue, Icelandic cod glue, red fish glue and white jade glue.

[0039] In this embodiment, 5 different types of fish glue (Zolo glue, Jinlong glue, Icelandic cod glue, red fish glue, and white jade glue) are used as test samples, and 13 portions of each of the 5 different types of fish glue are used, namely Zolo glue, Jinlong glue, Icelandic cod glue, red fish glue, and white jade glue. All samples are provided by Xiamen Customs Technical Center, as shown in Table 1.

[0040] Table 1 Information of five kinds of fish glue in the test samples

[0041]

[0042] All fish glue samples were cut into pieces with stainless steel scissors or smashed with hammers, put into a high-speed grinder for crushing and grinding, and then passed through a 60-mesh sieve. The obtained fish glue powder was stored in a food-grade sealed bag and placed in a cool place at room temperature for testing.

[0043] The method for amino acid determination is as follows:

[0044] Preparation of sample determination solution: Refer to GB 5009.124-2016 "National Food Safety Standard Determination of Amino Acids in Food", accurately weigh 0.100g of fish gelatin powder (accurate to 0.001g) and place it in a hydrolysis bottle, add 10mL of 6mol / L hydrochloric acid solution, and then add 4 drops of phenol with a concentration of 80%, then freeze for 5min, continuously fill with nitrogen for 10min, and seal during the nitrogen filling process. Place the sealed hydrolysis bottle in an electric blast drying oven at 110℃±1℃ for hydrolysis for 24h, take it out and cool it to room temperature. Open the hydrolysis bottle, rinse the hydrolysis bottle with water several times, filter the hydrolyzate, accurately determine the volume to 50mL, and shake and mix. Accurately draw 200uL of sample hydrolyzate into a test tube, blow dry with a nitrogen blower at 45℃, then use 200μL of secondary water to dissolve and remove acid, vortex, and finally blow it completely with nitrogen to dry. Add 1.0 mL of sodium citrate buffer solution with a pH of 2.2 to the test tube, vortex mix, use a syringe to draw the solution through a 0.22 μm filter membrane, transfer it to a sample injection bottle, and use it as the sample measurement solution for use on the machine.

[0045] Preparation of standard liquid for use in the machine: accurately pipette an appropriate amount of the amino acid mixed solution, dilute it to the corresponding concentration with pH = 2.2 buffer solution for use in the machine, vortex mix, and set aside for use in the machine.

[0046] Instrumental determination conditions: chromatographic column: sulfonic acid type cationic resin; eluent flow rate: 35mL / h; detection wavelength: 440+570nm; injection volume: 20μL; elution procedure is shown in Table 2. The sample determination solution and the mixed amino acid standard solution are injected into the amino acid analyzer with equal injection volume, and the concentration of amino acids in the sample is determined by calculating the ratio of peak area and concentration by the external standard method. During the acid hydrolysis process, cysteine ​​will be oxidized and lost, resulting in a low content, and tryptophan will be completely destroyed and cannot be determined. Therefore, this method can actually only accurately determine the content of 16 amino acids.

[0047] Table 2 Elution program

[0048]

[0049] The standard and sample liquid were injected separately. Since proline has the maximum absorption wavelength at 440nm, 440nm is used to detect proline, and 570nm is used to determine other amino acids except proline. Figure 1 , Figure 2 As shown, it can be seen that the separation effect between the 16 amino acids is good.

[0050] In order to further understand the amino acid composition of the five fish maw samples, the amino acid nutritional value of fish maw was evaluated by referring to the standard scoring model value of essential amino acids for human body proposed by WHO / FAO in 1973 and the amino acid ratio coefficient method. The amino acid ratio RAA (Ratio of amino acid), amino acid ratio coefficient RC (Ratio coefficient), and amino acid ratio coefficient score SRC (Score of ratio coefficient) were calculated respectively according to the following formula:

[0051] RAA = [Content of a certain essential amino acid in the protein of the sample to be tested (mg / g protein)] / [Content of the corresponding essential amino acid in the FAO / WHO scoring standard model (mg / g protein)] (1)

[0052] RC = RAA of a certain essential amino acid in the sample to be tested / average RAA of various amino acids (2)

[0053] CV (coefficient of variation of RC) = standard deviation of RC / mean value of RC (3)

[0054] SRC=100×(1-CV) (4)

[0055] Note: RC is a measure of the ratio of the amino acid composition in food to the equivalent amount of ideal amino acids. RC>1 indicates a relative excess of a specific amino acid, while RC<1 indicates a relative lack of the amino acid. The one with the smallest RC value is called the first limiting amino acid in food. The closer the SRC is to 100, the higher the nutritional value of the food and the more balanced the amino acid content, and vice versa.

[0056] According to the results of the determination of 16 amino acids in the five fish maw samples, the nutritional status was analyzed and the results are shown in Table 3.

[0057] As can be seen from Table 3, all five fish glues contain 16 kinds of amino acids, and the total amino acid content is about 62.76%-70.84%. Among them, the highest total amino acid content is Jinlong glue, about 70.84%, and the lowest content is red fish glue, about 62.76%. Except for the small difference in the content of phenylalanine, the contents of the other 15 amino acids are significantly different. The amino acid with the highest content in the five fish glues is glycine, as high as 15.41-17.89g / 100g, accounting for about 25% of the total. Glycine is one of the most abundant amino acids in collagen. It is an amino acid composed of endogenous antioxidant reduced glutathione. It has been proven in a large number of animal experiments that it has good antioxidant effects and life extension functions. It can be seen that fish glue has the potential to beautify and delay aging.

[0058] Table 3 Amino acid composition and content of fish glue (g / 100g)

[0059]

[0060]

[0061] Note: Different superscript letters in the same row indicate significant differences in content (P < 0.05)

[0062] According to different properties and uses, amino acids can be divided into flavoring amino acids and medicinal amino acids. Fish glue has a delicious taste and has been regarded as a "sea delicacy" since ancient times. The presence of flavoring amino acids can significantly enhance the taste and flavor of fish glue. According to the different flavor characteristics of flavoring amino acids, they can be divided into sweet amino acids SAA (Sweet amino acids), bitter amino acids BAA (Bitterness amino acids), and UAA umami amino acids (Umami amino acids). As shown in Table 4, the flavoring amino acids of the five types of fish glue account for 52.40%-57.71%, 20.28%-21.78%, and 59.94%-63.25% of TAA, respectively, among which UAA accounts for the highest proportion, which also explains why fish glue tastes delicious. The content of SAA and UAA in Jinlong glue is the highest, which is significantly different from the other four types of fish glue (P < 0.05), and the content of BAA is low. The taste is mainly sweet and fresh, and it has a slight advantage in taste and flavor. Therefore, consumers who care about the taste of fish glue can give priority to Jinlong glue.

[0063] Medicinal amino acids (MAA) are amino acids that can treat or prevent diseases and improve human physiological functions. The MAA / TAA of the five types of fish glue is about 64%. Jinlong glue has the highest content of medicinal amino acids, while Zoro glue has the highest proportion of medicinal amino acids. Among them, arginine has the effect of nourishing the kidney and consolidating essence, and improving sexual dysfunction. In traditional Chinese medicine research, this characteristic of fish glue is combined with other traditional Chinese medicines to develop medicinal health products such as "Fish Maw Kidney-Nourishing Pills" and "Qi Ju Di Huang Paste". This shows that the five types of fish glue not only have delicious taste and unique flavor, but also have certain medicinal effects. The high content of flavor amino acids and medicinal amino acids in fish glue provides a broad space for its development and application in condiments, flavor enhancers, and nutritional health products. Through scientific extraction and processing, more high value-added products can be developed to meet the needs of the market and consumers.

[0064] Table 4 Flavor amino acid and medicinal amino acid content of fish glue (g / 100g)

[0065]

[0066] Note: 1Sweet amino acids: Ser, Gly, Ala, Lys, Pro, Thr; 2 Bitter amino acids: His, Val, Arg, Phe, Ile, Leu, Met; 3 Umami amino acids: Glu, Ala, Gly, Asp, Arg; 4 Medicinal amino acids: Arg, Phe, Ile, Leu, Met, Gly, Glu, Lys, Tyr. Different superscript letters in the same row indicate significant differences in content (P < 0.05).

[0067] The present embodiment evaluates the nutritional value of fish glue by comparing the essential amino acids in fish glue with the WHO / FAO amino acid pattern spectrum. The closer the amino acid content ratio in the food is to the WHO / FAO amino acid pattern spectrum, the more easily the food has protein absorbed by the human body. If the difference is particularly large, it is not easy to absorb after eating. As shown in Table 5, the amino acid pattern spectrum ratios of all fish glues are very low and all fail to reach the WHO / FAO standard value, indicating that the rationality of the amino acid composition of fish glue is not good enough and is not suitable as a daily main protein source food. Among them, the value of lysine in Icelandic cod glue and the value of threonine in Jinlong glue are closest to the standard.

[0068] Table 5 Comparison of the mass fraction of EAA to TAA in fish maw with the WHO / FAO model spectrum (%)

[0069]

[0070] The amino acid ratio coefficient method is one of the commonly used methods to evaluate the nutritional value of amino acids in food. This method is based on the amino acid balance theory and evaluates the amino acid nutrition by comparing the difference between the ratio of essential amino acids in the target substance and the WHO / FAO amino acid pattern spectrum or the high-quality protein pattern spectrum.

[0071] As shown in Table 6, the RC values ​​of phenylalanine + tyrosine, lysine, and threonine of the five types of fish glue are all greater than 1, and the RC values ​​of lysine and threonine of several fish glues are greater than 1.3, which means that there is a relative surplus. When the content of a certain essential amino acid in food is relatively low or relatively lacking, it will become a key factor limiting the effective utilization of other amino acids, thereby weakening the overall nutritional value. These essential amino acids with the lowest content are called the first limiting amino acids. By comparing the size of RC, it is concluded that the first limiting amino acid of Zorro glue, Jinlong glue, and Iceland cod glue is leucine, that of red fish glue is isoleucine, and that of white jade glue is valine. It is recommended that grains, beans, meat, dairy products, etc. can be eaten together with fish glue to increase the intake of essential amino acids in the overall diet. For example, canned fish glue quinoa, fish glue chicken, fish glue stewed with fresh milk, etc., thereby producing a complementary effect of protein, so that the essential amino acids contained in them complement each other, and the ratio of essential amino acids can be improved, so as to achieve the effect of improving the nutritional value of fish glue food. Red fish maw has the highest SRC value, which means that the essential amino acid content of red fish maw is the most balanced among the five types of fish maw. This also shows that the more expensive fish maw is, the more nutritious it is.

[0072] It can be seen from this that future research and development of fish maw products should be committed to in-depth exploration of the complementary mechanism between fish maw and various proteins, and use food processing technologies such as enzymatic hydrolysis and fermentation to optimize the texture, taste and solubility of mixed food, so that the final product not only retains the rich collagen, minerals and unique flavor of fish maw, but also incorporates the high-quality amino acid composition, dietary fiber and low cholesterol characteristics of other proteins, thereby maximizing and balancing the nutritional value.

[0073] Table 6 Amino acid ratio coefficient of fish glue

[0074]

[0075]

[0076] S2, the type and content of the amino acids obtained in S1 are subjected to Kaiser-Meyer-Olkin and Bartlett tests, and principal component analysis is performed by verification. The principal component data of the test sample are used to draw a principal component analysis two-dimensional graph as a determination map; the type of the isinglass sample to be measured is determined according to the distribution quadrant of the principal component of the isinglass sample to be measured in the determination map;

[0077] If the verification fails, return to step S1; if the type of the determined fish maw sample belongs to the 5 test samples and is not unique, proceed to the next step.

[0078] In the present embodiment, first the amino acid composition and content of 5 kinds of fish glues are subjected to sampling suitability test Kaiser-Meyer-Olkin (KMO) and Bartlett test, which are used to test the degree of association between each factor, and whether it is suitable for principal component analysis. Generally, KMO≥0.6, significance≤0.05 meet the conditions for principal component analysis, as shown in Table 7, KMO is 0.686>0.6, and Bartlett's significance is 0, indicating that the prerequisite for principal component analysis is met by inspection. Therefore, principal component analysis is directly carried out below.

[0079] Table 7 KMO and Bartlett's test

[0080]

[0081] Principal Component Analysis (PCA) is usually the first step in data analysis and is used to detect outliers in patterns. It converts raw data into principal components (PCs) by PCA. By drawing two-dimensional or three-dimensional graphs, the main features in the data can be effectively extracted, and the relationship and distribution between different samples can be visualized.

[0082] The principal component analysis of 16 amino acids in 5 kinds of fish glue was performed, and four principal components with eigenvalues ​​greater than 1 were extracted, among which principal component 1, principal component 2, principal component 3, and principal component 4 provided variance contribution rates of 37.77%, 28.96%, 10.42%, and 8.53%, respectively, and the cumulative contribution rate was greater than 85%, indicating that these four principal components have already comprehensively reflected the basic information of the original variables. Among the first principal component, glycine, alanine, arginine, and proline have the largest weights, while the second principal component is composed of threonine, methionine, isoleucine, lysine, aspartic acid, serine, and glutamic acid. The third principal component is valine, leucine, and histidine, and the fourth principal component is phenylalanine and tyrosine.

[0083] The PCA two-dimensional graph of the five types of fish maws was established using principal component 1 and principal component 2. The cumulative variance contribution rate of the first two principal components was 66.7%. Figure 3 It can be seen that the amino acid content of the five fish glues is different, the clustering effect between each type is good, and there is no abnormal observation value. Iceland cod glue is distributed in the first quadrant, Zorro glue and Jinlong glue are both distributed in the fourth quadrant, and the separation effect between samples is very good, but the red fish glue and white jade glue samples are obviously clustered in the second quadrant, indicating that the amino acid content between the two fish glues is similar, so further analysis is needed.

[0084] Table 8 Eigenvalues ​​and variance contribution rates of principal components

[0085]

[0086] In order to more comprehensively reflect the comprehensive information of the amino acid quality of fish glue, a comprehensive score calculation formula was established based on the rotated component matrix (Table 9). The weights were calculated by the following formula (5), and the weights of the four eigenvalues ​​were 0.44, 0.34, 0.12, and 0.10, respectively. The scores were added according to the different weights of each principal component, and finally a comprehensive score model of fish glue was established, and the average was calculated to obtain the final comprehensive scores of the five different fish glues. The scores of the five fish glues are Jinlong glue>Zorro glue>Icelandic cod glue>White jade glue>Red fish glue, indicating that the comprehensive quality of amino acids in Jinlong glue is higher, and it is a variety with better amino acid quality.

[0087] Weight = eigenvalue / sum of eigenvalues ​​(5)

[0088] Comprehensive score calculation function:

[0089] F1=0.458X1-0.130X2+0.118X3-0.861X4-0.122X5-0.121X6+0.062X7-0.160X8-0.560X9+0.359X 10 +0.870X 11 +0.970X 12 +0.218X 13 +0.183X 14 +0.880X 15 +0.711X 16 (6)

[0090] F 2＝ 0.761X1+0.248X2+0.728X3+0.154X4+0.386X5+0.115X6+0.733X7+0.904X8+0.693X9+0.704X 10 +0.298X 11 -0.033X 12 -0.059X 13 +0.391X 14 +0.357X 15 -0.256X 16 (7)

[0091] F3=0.130X1+0.794X2+0.570X3-0.242X4+0.647X5-0.349X6+0.564X7+0.312X8+0.129X9+0.346X 10 -0.196X 11 +0.115X 12 +0.296X 13 +0.817X 14-0.104X 15 -0.585X 16 (8)

[0092] F 4＝ 0.313X1+0.195X2+0.043X3-0.163X4-0.299X5+0.871X6-0.099X7-0.019X8-0.167X9+0.035X 10 -0.173X 11 +0.081X 12 +0.802X 13 -0.018X 14 -0.024X 15 +0.161X 16 (9)

[0093] F (comprehensive score) = 0.44F1 + 0.34F2 + 0.12F3 + 0.10F4 (10)

[0094] Table 9 Rotated component matrix

[0095]

[0096]

[0097] Table 10 Comprehensive scores of 5 types of fish maw

[0098]

[0099] S3, utilize the amino acid kind and content of described test sample sample, establish Fisher discriminant analysis function model, substitute the amino acid kind and content of described fish glue sample to be tested into Fisher discriminant analysis function model, and judge the fish glue kind with the maximum function value as the kind of described fish glue sample to be tested.

[0100] In step S2, the principal component analysis shows that there are differences in the amino acid composition of different types of fish glue, but there is still overlap between some fish glues, which is not enough to distinguish, such as red fish glue and white jade glue. Therefore, in order to better distinguish different types of fish glue, this embodiment uses the amino acid composition and content of fish glue to establish a Fisher discriminant analysis function model.

[0101] Discriminant Analysis is a statistical method used to determine how a set of variables can best distinguish or discriminate samples from two or more predetermined groups. This method determines which category a sample belongs to by establishing one or more discriminant functions, using a large amount of data on the research object to determine the coefficients to be determined in the discriminant function, and calculating the discriminant index. Discriminant analysis plays an important role in the food and medical industries due to its simplicity, interpretability, data dimensionality reduction ability, multi-category classification effect, and a wide range of applications.

[0102] As shown in Table 11: Consistent with the results of principal component analysis, four canonical discriminant function eigenvalues ​​greater than 1 were obtained. The cumulative variance contribution rate of the first typical discriminant function was the largest, reaching 72.7%, and the typical correlation was 0.998, which was a good correlation.

[0103] According to the Fisher function discriminant coefficient obtained in Table 12, the function discriminant formula (X1-X 16 Represents the content of 16 kinds of amino acids, g / 100g):

[0104] Y1(Zolo glue)=-62.613X1+482.155X2-204.691X3+……-256.377X 15 +822.085X 16 -4133.154 (11)

[0106] Y2(Jinlongjiao)=-85.606X1+511.147X2-184.958X3+……-342.194X 15 +487.991X 16 -4518.568 (12)

[0108] Y3 (Icelandic cod glue) = 109.370X1 + 329.683X2 - 138.884X3 + ... - 443.431X 15 +293.861X 16 -5229.420 (13)

[0110] Y4 (red fish glue) = 35.362X1 + 326.520X2 - 116.658X3 + ... - 349.149X 15 +105.635X 16 -3538.691 (14)

[0112] Y5 (white jade glue) = 0.502X1 + 347.446X2 - 122.157X3 + ... - 365.040X 15 +91.962X 16 -3920.194 (15)

[0114] When judging that the unknown sample belongs to one of the above five types of fish maws (according to the PCA two-dimensional graph, if it falls in the corresponding quadrant, it is inferred that the sample is the type of fish maw corresponding to the quadrant), the 16 amino acid contents of the unknown sample are substituted into the above function discriminant to obtain five Y values. The fish maw type with the largest Y value is judged to be the type of the unknown sample.

[0115] In order to verify the accuracy of the model, the training set data was back-substituted into the above function discriminant for calculation, and the test set was tested at the same time. The discriminant classification results are shown in Table 13. The discriminant accuracy of the fish glue types in the test set was 100%, the discriminant accuracy of the validation set was 93.33%, and the average accuracy was 96.67%. This shows that the model can distinguish these five different types of fish glue well. One red fish glue sample was misjudged as white jade glue, indicating that the amino acid content of the two fish glues is highly similar and easy to confuse, which is consistent with the results of the principal component analysis. Therefore, it is necessary to expand the number of fish glue samples to improve the universality and accuracy of the discriminant function.

[0116] Table 11 Canonical discriminant function eigenvalues

[0117]

[0118] Table 12 Fisher function discriminant coefficient

[0119]

[0120]

[0121] Table 13 Identification and classification results of fish maw types

[0122]

[0123] Embodiment 2

[0124] The present invention also provides a terminal device for distinguishing fish glue types based on amino acid content analysis combined with chemometrics, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned method embodiment of the first embodiment of the present invention are implemented.

[0125] Further, as an executable scheme, the terminal device for distinguishing fish glue types based on amino acid content analysis combined with chemometrics can be a computing device such as a desktop computer, a notebook, a PDA, and a cloud server. The terminal device for distinguishing fish glue types based on amino acid content analysis combined with chemometrics may include, but is not limited to, a processor and a memory. Those skilled in the art will appreciate that the composition structure of the terminal device for distinguishing fish glue types based on amino acid content analysis combined with chemometrics is only an example of a terminal device for distinguishing fish glue types based on amino acid content analysis combined with chemometrics, and does not constitute a limitation on the terminal device for distinguishing fish glue types based on amino acid content analysis combined with chemometrics, and may include more or less components than the above, or combine certain components, or different components, such as the terminal device for distinguishing fish glue types based on amino acid content analysis combined with chemometrics may also include input and output devices, network access devices, buses, etc., and the embodiment of the present invention does not limit this.

[0126] Further, as an executable solution, the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the terminal device for distinguishing fish glue types based on amino acid content analysis combined with chemical metrology, and various interfaces and lines are used to connect the various parts of the terminal device for distinguishing fish glue types based on amino acid content analysis combined with chemical metrology.

[0127] The memory can be used to store the computer program and / or module, and the processor realizes the various functions of the terminal device for distinguishing the fish glue types based on amino acid content analysis combined with chemometric method by running or executing the computer program and / or module stored in the memory, and calling the data stored in the memory. The memory can mainly include a storage program area and a storage data area, wherein the storage program area can store an operating system, an application required for at least one function; the storage data area can store data created according to the use of the mobile phone, etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0128] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method in the embodiment of the present invention are implemented.

[0129] The module / unit integrated in the terminal device for distinguishing fish glue types based on amino acid content analysis combined with chemometric method can be stored in a computer-readable storage medium if it is implemented in the form of a software functional unit and sold or used as an independent product. Based on such an understanding, the present invention implements all or part of the process in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can be implemented when executed by a processor. The steps of each method embodiment described above. Wherein, the computer program includes a computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory) and software distribution medium, etc. that can carry the computer program code.

[0130] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0131] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0132] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for distinguishing fish glue types based on amino acid content analysis combined with stoichiometric method, characterized in that: The following steps are involved: S1. Obtain the types and contents of amino acids of the fish glue samples to be tested, as well as the types and contents of amino acids of five test samples, namely, Zorro glue, Jinlong glue, Icelandic cod glue, red fish glue, and white jade glue; S2, the amino acid types and contents obtained in S1, sampling suitability test and Bartlett test are carried out, and principal component analysis is carried out by verification. The principal component data of the test sample are used to draw a principal component analysis two-dimensional graph as a determination map; the type of the isinglass sample to be measured is determined according to the distribution quadrant of the principal component of the isinglass sample to be measured in the determination map; If the verification fails, the process returns to step S1; if the type of the determined fish maw sample belongs to the five test samples and is not unique, the process proceeds to the next step; S3, utilize the amino acid kind and content of described test sample sample, establish Fisher discriminant analysis function model, substitute the amino acid kind and content of described fish glue sample to be tested into Fisher discriminant analysis function model, and judge the fish glue kind with the maximum function value as the kind of described fish glue sample to be tested.

2. The method for distinguishing fish glue types based on amino acid content analysis combined with stoichiometry according to claim 1, characterized in that: The method for obtaining the types and contents of amino acids in a sample in S1 comprises the following steps: S11. Cut the sample into pieces with stainless steel scissors or smash it with a hammer, put it into a grinder for crushing and grinding, and then sieve it to collect the gelatin powder; S12, accurately weigh the fish glue powder and place it in a hydrolysis bottle, add hydrochloric acid solution, then add phenol, then freeze, continuously fill with nitrogen, and seal during the nitrogen filling process; put the sealed hydrolysis bottle into a heating environment for hydrolysis, take it out and cool it to room temperature; open the hydrolysis bottle, rinse the hydrolysis bottle with water, filter the hydrolyzate, accurately determine the volume, shake and mix, accurately draw the sample hydrolyzate in a test tube, blow dry with a nitrogen blower, then dissolve and remove acid with secondary water, vortex, and finally blow completely with nitrogen to dry; add sodium citrate buffer solution to the test tube, vortex and mix, draw the solution filter membrane with a syringe, transfer it to a sample injection bottle, and use it as a sample determination liquid for standby on the machine; prepare a standard mixed solution of amino acids at the same time, dilute it to the corresponding concentration with the machine buffer solution, vortex and mix, as a mixed amino acid standard solution, wait to be used on the machine; S13. Use an amino acid analyzer with a sulfonic acid cationic resin chromatographic column and detection wavelengths of 440nm and 570nm. Inject the sample test solution and the mixed amino acid standard solution into the amino acid analyzer in equal amounts, calculate the ratio of peak area and concentration by the external standard method, and determine the type and content of amino acids in the sample.

3. The method for distinguishing fish glue types based on amino acid content analysis combined with stoichiometry according to claim 2, characterized in that: Accurately weigh 0.100 g of gelatin powder in S12 and place it in a hydrolysis bottle to an accuracy of 0.001 g. Add 10 mL 6mol / L hydrochloric acid solution, then add 4 drops of phenol with a concentration of 80wt%, then freeze for 5min, continuously fill with nitrogen for 10min, and seal during the nitrogen filling process; put the sealed hydrolysis bottle into an electric heated air drying oven at 110℃±1℃ for hydrolysis for 24h, take it out and cool it to room temperature; open the hydrolysis bottle, rinse the hydrolysis bottle with water, filter the hydrolyzate, accurately determine the volume to 50mL, and oscillate to mix; accurately draw 200uL of sample hydrolyzate into a test tube, blow dry with a nitrogen blower at 45℃, then dissolve and remove acid with 200μL of secondary water, vortex, and finally blow completely with nitrogen to dry; add 1.0mL of sodium citrate buffer solution with pH=2.2 to the test tube, vortex to mix, use a syringe to draw the solution through a 0.22μm filter membrane, transfer it to the injection bottle, and use it as the sample determination solution for standby on the machine.

4. The method for distinguishing fish glue types based on amino acid content analysis combined with stoichiometry according to claim 2, characterized in that: The eluent flow rate in S13 is 30-40 mL / h; the injection volume is 15-25 μL; Optionally, a sampling suitability test and a Bartlett test are performed in S2. When the obtained KMO is ≥ 0.6 and the significance is ≤ 0.05, it is determined to have passed the validation.

5. The method for distinguishing fish glue types based on amino acid content analysis combined with stoichiometry according to claim 4, characterized in that: The principal component analysis described in S2 includes principal component analysis of the contents of 16 amino acids in 5 test samples: threonine, valine, methionine, isoleucine, leucine, phenylalanine, lysine, aspartic acid, serine, glutamic acid, glycine, alanine tyrosine, histidine, arginine, and proline, and extracting four principal components with eigenvalues ​​greater than 1, namely principal component 1, principal component 2, principal component 3, and principal component 4. Among them, glycine, alanine, arginine, and proline have the largest weights in principal component 1, and principal component 2 is composed of threonine, methionine, isoleucine, lysine, aspartic acid, serine, and glutamic acid; principal component 3 is valine, leucine, and histidine, and principal component 4 is phenylalanine and tyrosine.

6. The method for distinguishing fish glue types based on amino acid content analysis combined with chemometrics according to claim 5, characterized in that: The PCA two-dimensional graph of the five test samples was established using the principal component 1 and the principal component 2. In the obtained determination graph, Icelandic cod glue was distributed in the first quadrant, Zorro glue and Jinlong glue were separated from each other and distributed in the fourth quadrant, and red fish glue and white jade glue were concentrated in the second quadrant.

7. The method for distinguishing fish glue types based on amino acid content analysis combined with chemometrics according to any one of claims 1 to 6, characterized in that: In S3, according to the types and contents of amino acids in the test samples and the discriminant analysis method, the characteristic values ​​of the canonical discriminant function and the discriminant coefficient of the Fisher function are obtained, and then the discriminant analysis function models of the five types of fish glue are established.

8. The method for distinguishing fish glue types based on amino acid content analysis combined with chemometrics according to claim 7, characterized in that: The discriminant analysis function model is tested for accuracy, a training set and a test set are constructed using the test samples, the types and contents of amino acids in the training set and the test set are determined, and training set data and test set data are obtained; Substitute the training set data back into the discriminant analysis function model discriminant to calculate, and at the same time, test the test set data.

9. A terminal device for distinguishing fish maw types based on amino acid content analysis combined with chemometrics, characterized in that: The method comprises a processor, a memory and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of the method according to any one of claims 1 to 8 when executing the computer program.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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