Method for rapidly detecting aging years of dried orange peel

Abstract

The invention discloses a method for rapidly detecting the aging year of pericarpium citri reticulatae, which comprises the following steps: constructing a function model of the aging year of pericarpium citri reticulatae and physical and chemical index parameters of pericarpium citri reticulatae, and then inputting corresponding physical and chemical index parameter values of pericarpium citri reticulatae of a pericarpium citri reticulatae sample to be detected into the function model to obtain the aging year of the sample to be detected. According to the method, the advantages of optical and chemical analysis technologies are combined, through simple determination of physical and chemical indexes, the operation is simple, the aging years of the dried orange peel can be detected in a short time, and the detection efficiency is improved. Through double verification of quantitative analysis and statistical analysis, personal errors are reduced, and the accuracy and objectivity of detection are improved. The method can also be popularized to aging year detection of other traditional Chinese medicinal materials or agricultural products, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of Chinese medicinal material detection, and in particular relates to a method for quickly detecting the aging year of tangerine peel. Background Art

[0002] Tangerine peel is a plant of Rutaceae Citrμs reticμlata Blanco The dried mature peel of its cultivars is divided into "Chenpi" and "Guang Chenpi" (Xinhui Chenpi), and among them, Guang Chenpi is of better quality. Guang Chenpi is a cultivated variety of the citrus plant of the Rutaceae family. Citrus reticulata The dried and mature peel of 'Chachi' has the effects of regulating qi and strengthening the spleen, drying dampness and resolving phlegm. As a famous Chinese medicinal material and condiment, the quality of dried tangerine peel is closely related to the aging year. Due to different aging years, its components and pharmacological activities are different. It is said that "the older the tangerine peel, the better". Most studies also believe that as the storage years of tangerine peel increase, its medicinal value is higher. At present, the tangerine peel on the market is mainly tangerine peel with an aging year of less than 12 years. Therefore, it is of great practical application value and significance to distinguish and identify the storage years of tangerine peel.

[0003] Traditional identification of tangerine peel age mostly relies on empirical judgment, usually by experienced appraisers to make preliminary assessments based on its external characteristics such as smell, appearance, and color. Although these methods have certain basis, they are highly subjective and cannot achieve accurate quantification. With the advancement of instrument technology, instrumental analysis methods have been applied to the identification of tangerine peel age, mainly including infrared spectroscopy, liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS). Although more objective identification methods such as instrumental analysis can provide a more scientific basis, their process is complicated, time-consuming, and the equipment is expensive. In addition, they require highly professional operators, which leads to their limitations in rapid detection applications and makes it difficult to promote and apply them on a large scale. Therefore, it is urgent to develop a simple, fast, and accurate method for detecting the aging year of tangerine peel. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects and shortcomings in the prior art and provide a method for quickly detecting the aging year of tangerine peel.

[0005] The above-mentioned object of the present invention is achieved through the following technical solutions: The present invention first provides a method for quickly detecting the aging year of tangerine peel, comprising the following steps: S1. Constructing a function model of tangerine peel aging years and tangerine peel physical and chemical index parameters; S2. Input the physical and chemical index parameter values ​​of the tangerine peel samples to be tested into the function model to obtain the aging year of the samples to be tested; The tangerine peel physical and chemical index parameters include pH value, conductivity and 420nm absorbance.

[0006] The present invention measures simple physicochemical indicators of tangerine peel, such as pH value, conductivity, 420nm absorbance, reducing sugar, Fe²⁺ concentration and starch content. By measuring the above indicators and screening them in combination, the accuracy of the above indicators in predicting the aging year of tangerine peel is judged through univariate / multivariate linear regression fitting equations. Studies have shown that the aging year of tangerine peel has a high correlation with the pH value, conductivity and 420nm absorbance of tangerine peel. The tangerine peel of unknown aging year can be detected by establishing a function model between the above indicators and the aging year of tangerine peel. Specifically, the aging year of tangerine peel cannot be accurately judged by measuring a single physicochemical indicator, while the aging year of tangerine peel can be judged more accurately by measuring three detection indicators including pH value, conductivity and 420nm absorbance. The degree of fit (R 2 ) exceeded 0.90; among them, by measuring pH value, conductivity and 420nm absorbance, the goodness of fit (R 2 ) reaches 0.9106, and the error is controlled within ±1 year, indicating that the aging year of tangerine peel can be predicted more accurately, and the detection time is greatly shortened. The present invention realizes the accurate determination of the aging year of tangerine peel by combining quantitative analysis with statistical analysis, and improves the objectivity and accuracy of the detection.

[0007] Furthermore, the tangerine peel is tangerine peel from Guangdong.

[0008] Furthermore, the aging method of the tangerine peel is natural aging.

[0009] Furthermore, the aging period of the tangerine peel is 1 to 12 years.

[0010] Furthermore, the function model in step S1 is a multiple linear regression fitting equation.

[0011] Furthermore, the tangerine peel physical and chemical indicators described in step S1 are obtained by measuring tangerine peel water extract.

[0012] Furthermore, the tangerine peel water extract is obtained by crushing the tangerine peel and then subjecting it to ultrasonic water extraction.

[0013] Preferably, the tangerine peel water extract is obtained by crushing the tangerine peel, adding water at a mass ratio of 1:48-52, and then ultrasonically extracting it.

[0014] Preferably, the tangerine peel water extract is obtained by crushing the tangerine peel, adding water at a mass ratio of 1:50, and then ultrasonically extracting it.

[0015] Preferably, the ultrasonic extraction conditions are a temperature of 1 to 25° C. and an ultrasonic extraction time of 8 to 12 min.

[0016] Preferably, the ultrasonic extraction conditions are a temperature of 1 to 25° C. and ultrasonic extraction for 10 min.

[0017] Preferably, the tangerine peel water extract is directly used to determine the diluted pH value and conductivity, and the tangerine peel water extract is diluted 10 times and then the absorbance at 420 nm is determined.

[0018] Furthermore, the tangerine peel physical and chemical index parameters in step S1 are pH value, conductivity and 420nm absorbance; or pH value, conductivity, 420nm absorbance, reducing sugar content, Fe 2+ concentration and starch content.

[0019] Preferably, the reducing sugar content is determined by 3,5-dinitrosalicylic acid colorimetry; Fe 2+ The concentration was determined by 1,10-phenanthroline spectrophotometry; the starch content was determined by anthrone colorimetry.

[0020] Preferably, the tangerine peel physical and chemical index parameters in step S1 are pH value, conductivity and absorbance at 420 nm.

[0021] Preferably, when the tangerine peel physical and chemical index parameters are pH value, conductivity and 420nm absorbance, the function model is: ; The physicochemical index parameters of tangerine peel are a combination of pH value, conductivity, 420 nm absorbance, reducing sugar content, Fe 2+ When the concentration and starch content are equal, the function model is: ; In the functional model, Y is the aging year of tangerine peel, DI is the conductivity, Abs420 is the absorbance at 420 nm, RS is the reducing sugar content, Fe is Fe 2+ concentration, AM is the starch content.

[0022] Among them, pH and Abs420 are dimensionless, conductivity is in μS / cm, reducing sugar is in mg / g, Fe 2+ The unit of concentration is mg / g.

[0023] Furthermore, the tangerine peel sample to be tested in step S2 is tangerine peel water extract.

[0024] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for quickly detecting the aging year of tangerine peel, comprising constructing a function model of the aging year of tangerine peel and the physical and chemical index parameters of tangerine peel, and then inputting the tangerine peel physical and chemical index parameter values ​​corresponding to the tangerine peel sample to be tested into the function model to obtain the aging year of the sample to be tested. The method combines the advantages of optical and chemical analysis technologies, is simple to operate through the determination of simple physical and chemical indicators, can complete the detection of the aging year of tangerine peel in a short time, and improves the detection efficiency. Through the dual verification of quantitative analysis and statistical analysis, human errors are reduced, and the accuracy and objectivity of the detection are improved. The method can also be extended to the aging year detection of other Chinese medicinal materials or agricultural products, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the fitting equation diagram of the multiple linear regression obtained in Example 2.

[0026] Figure 2 is the pH value of the Guang Chenpi extract in different aging years.

[0027] Figure 3 The Fe content of the extracts of dried orange peels of different aging years 2+ concentration.

[0028] Figure 4 Abs420 value of Guang Chenpi extract in different aging years. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0030] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0031] During the aging process of Guang Chenpi, the pH value usually changes over time, and the acidity gradually changes, so it may be used as a reference indicator for predicting the aging year. Conductivity can reflect the change in the ion concentration of the material. During the aging process of Guang Chenpi, the decomposition and reorganization of the components will affect its conductivity. Abs420, as an absorbance indicator, can reflect the content of colored substances in the sample. Since the colored substances in Guang Chenpi will undergo significant changes during the aging process. As the aging process proceeds, sugar substances gradually decompose, so the change in reducing sugar content provides an important clue for predicting the aging year. Fe 2+The change of concentration can reflect the oxidation process of phenols and other compounds in the peel of dried orange. The starch content will gradually degrade during the aging process, and this change can affect the aging degree of the peel of dried orange. Although the above parameter index has a direct or indirect relationship with the aging year of the peel of dried orange, it is still uncertain whether it can be used as an effective index for predicting the aging year of the peel of dried orange. Therefore, the present invention detects and screens the above indexes, and the obtained parameter detection results are fitted and modeled to evaluate the prediction effect.

[0032] Example 1 Select Guang tangerine peel samples from 2012 to 2023, remove surface impurities, dry and other pretreatment steps, grind and crush them with a high-speed crusher and set aside to ensure the accuracy of the test results. At least 3 samples are taken for each year, and at least two complete tangerine peels are crushed.

[0033] 2. Parameter detection and analysis: The ground tangerine peel powder was added into ultrapure water (18.2 MΩ·cm -1 ), shake well and mix evenly, put it into an ultrasonic cleaner for ultrasonic extraction for 10 min (water bath temperature 1-25 ° C), and then put it into a high-speed centrifuge at 4500rpm for 5 min, take the supernatant, and get the tangerine peel water extract for use. Use a pH tester, conductivity tester and UV-visible spectrophotometer to measure pH value, conductivity DI (μS / cm), absorbance Abs420 at 420nm, reducing sugar RS (mg / g), Fe 2+ concentration (mg / g), starch content AM (mg / g). The pH value and conductivity were directly measured, the tangerine peel water extract was diluted 10 times and then measured on the machine for Abs420, and the reducing sugar content was determined by 3,5-dinitrosalicylic acid colorimetry; Fe 2+ The concentration was determined using the Ferrous Iron reagent kit (Cat. No. 103769) produced by Hach Company, USA, and the determination principle is based on the 1,10-phenanthroline spectrophotometry. The starch content (mg / g) was determined using the anthrone colorimetric method, taking 0.1g of ground tangerine peel powder and using the plant starch test kit (Cat. No. A148-1-1) of Nanjing Jiancheng Bioengineering Institute for determination.

[0034] Multiple linear regression analysis method: SPSS software was used to perform the analysis. Select "Analysis" → "Regression" → "Linear". The independent variable was the parameter index of the test, and the dependent variable was the actual year of Guang Chenpi. The error year was obtained by subtracting the actual year of the sample from the year predicted by the fitting equation. The goodness of fit R 2 The performance of the fit can be evaluated.

[0035] 3. Comprehensive judgment: The multivariate linear regression method was used for fitting modeling. The fitting results showed that the pH value, conductivity, Abs420, reducing sugar, Fe 2+ The determination coefficient (R²) of the fitting effect of concentration and starch content on year prediction reached 0.9138, and the error was controlled within ±1 year. The fitting equation of multiple linear regression was: .

[0036] Therefore, the present invention found that the aging year of tangerine peel has a significant effect on the pH value, conductivity, Abs420, reducing sugar, Fe 2+ There is a linear relationship between concentration and starch content, and the fitting effect is high. The above indicators can be tested to predict tangerine peel of different aging years. Tangerine peel with an aging year of more than 12 years can also be tested and calculated using the fitting equation. This law is universal.

[0037] Example 2 Select Guang tangerine peel samples from 2012 to 2023, remove surface impurities, dry and other pretreatment steps, grind and crush them with a high-speed crusher and set aside to ensure the accuracy of the test results. At least 3 samples are taken for each year, and at least two complete tangerine peels are crushed.

[0038] 2. Parameter detection and analysis: The ground tangerine peel powder was added into ultrapure water (18.2 MΩ·cm -1 ), shake well and mix evenly, put it into ultrasonic cleaning machine for ultrasonic extraction for 10 min (water bath temperature 1-25℃), then put it into high-speed centrifuge at 4500rpm for 5 min, take the supernatant to get tangerine peel water extract, set aside, use UV-visible spectrophotometer to measure pH value, conductivity, Abs420 respectively. Among them, pH value, conductivity, direct determination, tangerine peel water extract diluted 10 times to determine Abs420 value.

[0039] Multiple linear regression analysis was performed according to the method in Example 1.

[0040] 3. Comprehensive judgment: The multivariate linear regression method was used for fitting modeling. Figure 1 As shown in the figure, the fitting results show that the fitting effect determination coefficient (R²) of year prediction by pH value, conductivity and Abs420 reaches 0.9106, and the error is controlled within ±1 year. The fitting equation of multiple linear regression is: .

[0041] Therefore, the present invention found that the aging year of tangerine peel has a linear relationship with the pH value, conductivity, and Abs420 of tangerine peel, and the fitting effect is high. The tangerine peel of different aging years can be predicted by detecting the above indicators. Compared with Example 1, the detection time of this embodiment is shorter, and the aging year of tangerine peel can be detected more quickly.

[0042] Example 3 1. Sample preparation: Dry the samples of unknown year at 40℃, and then grind them into 100-200 mesh with a high-speed grinder for later use.

[0043] 2. Add the ground tangerine peel powder to ultrapure water (18.2 MΩ·cm -1 ), shake thoroughly and mix evenly, put it into an ultrasonic cleaner for ultrasonic extraction for 10 min, and then put it into a high-speed centrifuge for centrifugation at 4500 rpm for 5 min, and then take the supernatant for use.

[0044] 3. Parameter determination: The pH value of the supernatant was detected by a Mettler pH tester (the pH tester was calibrated with a standard solution in advance), and the conductivity of the supernatant was detected by a Rasen conductivity tester. The supernatant was diluted 10 times, and the absorbance at 420 nm was detected by a DR6000 UV-visible spectrophotometer. The average value of each parameter was taken for 3 times.

[0045] 4. Year prediction: Input the measured pH value, conductivity and Abs420 into the fitting equation of multiple linear regression , and the corresponding year of the sample is obtained. The prediction error of the tangerine peel year using this fitting equation is within 1 year.

[0046] Comparative Example 1 1. Sample pretreatment: Select Guang tangerine peel samples from 2012 to 2023, remove surface impurities, dry and other pretreatment steps, grind and crush them with a high-speed crusher and set aside to ensure the accuracy of the test results. At least 3 samples are taken for each year, and at least two complete tangerine peels are crushed.

[0047] 2. Parameter detection and analysis: The ground tangerine peel powder was added into ultrapure water (18.2 MΩ·cm -1 ), shake well and mix evenly, put it into ultrasonic cleaning machine for ultrasonic extraction for 10 min (water bath temperature 1-25℃), then put it into high-speed centrifuge at 4500rpm for 5 min, take the supernatant, and get the tangerine peel water extract for later use; use pH tester, conductivity tester and UV-visible spectrophotometer to measure pH value, Abs420, Fe 2+Concentration (mg / g), the pH value of the tangerine peel water extract was directly measured on the machine, and the absorbance at 420nm (Abs420 value) was measured on the machine after dilution 10 times, Fe 2+ The concentration was determined using the Ferrous Iron reagent kit (Cat. No. 103769) and DR6000 spectrophotometer (Method No. 8146) produced by Hach Company, USA. The determination principle is based on the 1,10-phenanthroline spectrophotometric method.

[0048] 3. Test results The pH test results of the water extract of Guang Chenpi samples from 2012 to 2023 are as follows: Figure 2 As shown in the figure, the pH value test results show that the pH value of the Guang Chenpi extract is linearly correlated with the Guang Chenpi aging year, and the correlation coefficient R 2 =0.77. With the increase of aging years, the pH value of tangerine peel extract decreased significantly, especially in the first 6 years, but the decline was not obvious after 6 years. Therefore, the aging year of Guang tangerine peel cannot be accurately determined by using pH value as the detection index.

[0049] Fe in water extracts of Guang Chenpi samples from 2012 to 2023 2+ The concentration test results are as follows Figure 3 As shown, Fe in tangerine peel extract 2+ The concentration increases with the years. The concentration is relatively low in the first three years. As the aging years increase, more effective substances in the dried orange peel are dissolved, the color of the extract is lighter, and the corresponding light absorption is also stronger. 2+ The concentration value also increased significantly, showing a linear correlation, and the correlation coefficient R 2 =0.46, but only Fe 2+ Concentration as a detection indicator cannot accurately determine the aging year of Guang Chenpi.

[0050] The Abs420 value test results of the water extract of Guang Chenpi samples from 2012 to 2023 are as follows Figure 4 As shown in Figure 2, the Abs420 value in the tangerine peel extract increases with the aging years, showing a linear correlation. 2 =0.61, but the aging year of Guang Chenpi cannot be accurately determined by using only Abs420 value as the detection index.

[0051] This comparative example provides the fitting data of univariate linear regression between three single simple physical and chemical indicators and the aging years of Guang Chenpi. The results show that selecting only one of the simple physical and chemical indicators cannot accurately determine the aging years of Guang Chenpi.

[0052] Comparative Example 2 Select Guang tangerine peel samples from 2012 to 2023, remove surface impurities, dry and other pretreatment steps, grind and crush them with a high-speed crusher and set aside to ensure the accuracy of the test results. At least 3 samples are taken for each year, and at least two complete tangerine peels are crushed.

[0053] 2. Parameter detection and analysis: The ground tangerine peel powder was added into ultrapure water (18.2 MΩ·cm -1 ), shake well and mix evenly, put it into ultrasonic cleaning machine for ultrasonic extraction for 10 min (water bath temperature 1-25℃), then put it into high-speed centrifuge at 4500rpm for 5 min, take the supernatant to obtain tangerine peel water extract, set aside, use pH tester, conductivity tester and UV-visible spectrophotometer to measure pH value, conductivity, reducing sugar (mg / g), Fe 2+ concentration (mg / g), starch content (mg / g). The pH value and conductivity were directly measured, and the reducing sugar content was determined by 3,5-dinitrosalicylic acid colorimetry; Fe 2+ The concentration was determined using the Ferrous Iron reagent pack (Cat. No. 103769) produced by Hach Company, USA, and the determination principle is based on the 1,10-phenanthroline spectrophotometry. The starch content was determined using the anthrone colorimetric method, taking 0.1 g of ground tangerine peel powder and using the plant starch test kit (Cat. No. A148-1-1) of Nanjing Jiancheng Bioengineering Institute for determination.

[0054] 3. Comprehensive judgment: The multivariate linear regression method was used for fitting modeling. The fitting results showed that the pH value, conductivity, reducing sugar, Fe 2+ The determination coefficient (R²) of the fitting effect of concentration and starch content on year prediction reached 0.8990, and the error was controlled within ±2 years.

[0055] Comparative Example 3 Select Guang tangerine peel samples from 2012 to 2023, remove surface impurities, dry and other pretreatment steps, grind and crush them with a high-speed crusher and set aside to ensure the accuracy of the test results. At least 3 samples are taken for each year, and at least two complete tangerine peels are crushed.

[0056] 2. Parameter detection and analysis: The ground tangerine peel powder was added into ultrapure water (18.2 MΩ·cm -1), shake well and mix evenly, put it into ultrasonic cleaning machine for ultrasonic extraction for 10 min (water bath temperature 1-25 ° C), and then put it into high-speed centrifuge 4500rpm centrifuge for 5 min, take the supernatant to get tangerine peel water extract, set aside, use pH tester, conductivity tester and UV-visible spectrophotometer to measure conductivity, reducing sugar (mg / g), Fe 2+ Concentration (mg / g), Abs420 and starch content (mg / g). The conductivity was directly measured, the Abs420 value was measured after the tangerine peel water extract was diluted 10 times, and the reducing sugar content was determined by the 3,5-dinitrosalicylic acid colorimetric method; Fe 2+ The concentration was determined using the Ferrous Iron reagent pack (Cat. No. 103769) produced by Hach Company, USA, and the determination principle is based on the 1,10-phenanthroline spectrophotometry. The starch content was determined using the anthrone colorimetric method, taking 0.1 g of ground tangerine peel powder and using the plant starch test kit (Cat. No. A148-1-1) of Nanjing Jiancheng Bioengineering Institute for determination.

[0057] 3. Judgment: The multivariate linear regression method was used for fitting modeling. The fitting results showed that the conductivity, reducing sugar, Fe 2+ The determination coefficient (R²) of the fitting effect of concentration, Abs420 and starch content on year prediction reached 0.8979, and the error was controlled within ±2 years.

[0058] Comparative Example 4 Select Guang tangerine peel samples from 2012 to 2023, remove surface impurities, dry and other pretreatment steps, grind and crush them with a high-speed crusher and set aside to ensure the accuracy of the test results. At least 3 samples are taken for each year, and at least two complete tangerine peels are crushed.

[0059] 2. Parameter detection and analysis: The ground tangerine peel powder was added into ultrapure water (18.2 MΩ·cm -1 ), shake well and mix evenly, put it into ultrasonic cleaning machine for ultrasonic extraction for 10 min (water bath temperature 1-25 ° C), and then put it into high-speed centrifuge 4500rpm centrifuge for 5 min, take the supernatant to get tangerine peel water extract, set aside, use UV-visible spectrophotometer to measure Abs420, reducing sugar (mg / g), Fe 2+ concentration (mg / g) and starch content (mg / g). The water extract of dried tangerine peel was diluted 10 times and the Abs420 value was determined. The reducing sugar content was determined by 3,5-dinitrosalicylic acid colorimetry; Fe 2+The concentration was determined using the Ferrous Iron reagent pack (Cat. No. 103769) produced by Hach Company, USA, and the determination principle is based on the 1,10-phenanthroline spectrophotometry. The starch content was determined using the anthrone colorimetric method, taking 0.1 g of ground tangerine peel powder and using the plant starch test kit (Cat. No. A148-1-1) of Nanjing Jiancheng Bioengineering Institute for determination.

[0060] 3. Comprehensive judgment: The multivariate linear regression method was used for fitting modeling. The fitting results showed that the Abs420, reducing sugar, Fe 2+ The determination coefficient (R²) of the fitting effect of concentration and starch content on year prediction reached 0.8116, and the error was controlled within ±2 years.

[0061] Comparative Example 5 Select Guang tangerine peel samples from 2012 to 2023, remove surface impurities, dry and other pretreatment steps, grind and crush them with a high-speed crusher and set aside to ensure the accuracy of the test results. At least 3 samples are taken for each year, and at least two complete tangerine peels are crushed.

[0062] 2. Parameter detection and analysis: The ground tangerine peel powder was added into ultrapure water (18.2 MΩ·cm -1 ), shake well and mix evenly, put it into ultrasonic cleaning machine for ultrasonic extraction for 10 min (water bath temperature 1-25℃), and then put it into high-speed centrifuge at 4500rpm for 5 min, then take the supernatant to obtain tangerine peel water extract for later use, and use UV-visible spectrophotometer to measure reducing sugar (mg / g), Fe 2+ concentration (mg / g), starch content (mg / g). The reducing sugar content was determined by 3,5-dinitrosalicylic acid colorimetry; Fe 2+ The concentration was determined using the Ferrous Iron reagent pack (Cat. No. 103769) produced by Hach Company, USA, and the determination principle is based on the 1,10-phenanthroline spectrophotometry. The starch content was determined using the anthrone colorimetric method, taking 0.1 g of ground tangerine peel powder and using the plant starch test kit (Cat. No. A148-1-1) of Nanjing Jiancheng Bioengineering Institute for determination.

[0063] 3. Comprehensive judgment: The multivariate linear regression method was used for fitting modeling. The fitting results showed that the 2+ The determination coefficient (R²) of the fitting effect of concentration and starch content on year prediction reached 0.5455, and the error was controlled within ±3 years.

[0064] Comparative Example 6 Select Guang tangerine peel samples from 2012 to 2023, remove surface impurities, dry and other pretreatment steps, grind and crush them with a high-speed crusher and set aside to ensure the accuracy of the test results. At least 3 samples are taken for each year, and at least two complete tangerine peels are crushed.

[0065] 2. Parameter detection and analysis: The ground tangerine peel powder was added into ultrapure water (18.2 MΩ·cm -1 ), shake and mix thoroughly, put it into an ultrasonic cleaner for ultrasonic extraction for 10 min (water bath temperature 1-25°C), and then put it into a high-speed centrifuge at 4500rpm for 5 min to obtain the supernatant to obtain the tangerine peel water extract for standby use. The Abs420, reducing sugar (mg / g) and starch content (mg / g) were measured by UV-visible spectrophotometer. The tangerine peel water extract was diluted 10 times to determine the Abs420 value, and the reducing sugar content was determined by the 3,5-dinitrosalicylic acid colorimetric method. The starch content was determined by the anthrone colorimetric method. 0.1g of ground tangerine peel powder was taken and measured using the plant starch test kit (item number A148-1-1) of Nanjing Jiancheng Bioengineering Institute.

[0066] 3. Comprehensive judgment: The multivariate linear regression method was used for fitting modeling. The fitting results showed that the fitting effect determination coefficient (R²) of year prediction by Abs420, reducing sugar and starch content reached 0.6210, and the error was controlled within ±2 years.

[0067] Comparative Example 7 Select Guang tangerine peel samples from 2012 to 2023, remove surface impurities, dry and other pretreatment steps, grind and crush them with a high-speed crusher and set aside to ensure the accuracy of the test results. At least 3 samples are taken for each year, and at least two complete tangerine peels are crushed.

[0068] 2. Parameter detection and analysis: The ground tangerine peel powder was added into ultrapure water (18.2 MΩ·cm -1 ), shake well and mix evenly, put it into ultrasonic cleaning machine for ultrasonic extraction for 10 min (water bath temperature 1-25℃), then put it into high-speed centrifuge at 4500rpm for 5 min, take the supernatant to obtain tangerine peel water extract, set aside, use pH tester, conductivity tester and UV-visible spectrophotometer to measure pH value, conductivity, reducing sugar content (mg / g), Fe 2+concentration (mg / g), Abs420, pH value and conductivity were directly measured, the Abs420 value was measured after the tangerine peel water extract was diluted 10 times, and the reducing sugar content was determined by the 3,5-dinitrosalicylic acid colorimetric method; Fe 2+ The concentration was determined using the Ferrous Iron reagent kit (Cat. No. 103769) produced by Hach Company (USA), which is based on the 1,10-phenanthroline spectrophotometric method.

[0069] 3. Comprehensive judgment: The multivariate linear regression method was used for fitting modeling. The fitting results showed that the pH value, conductivity, reducing sugar, Fe 2+ The determination coefficient (R²) of the fitting effect of concentration and Abs420 on year prediction reached 0.9010, and the error was controlled within ±2 years.

[0070] Based on Examples 1 to 2 and Comparative Examples 1 to 7, it can be seen that a single physical and chemical index is difficult to be used to detect the aging year of tangerine peel. The combination of multiple physical and chemical indicators (pH value, conductivity, Abs420, reducing sugar, Fe 2+ concentration, starch content), can better detect the aging year of tangerine peel, however, the detection of reducing sugar, Fe 2+ The time required for the determination of concentration and starch content is relatively long, usually more than 3 hours. Therefore, reducing the detection indexes can better realize the rapid detection of the aging year of tangerine peel. Among them, only the pH value, conductivity, and Abs420 of Guang tangerine peel can be measured, which can also accurately detect the aging year of tangerine peel. At the same time, the detection time is greatly shortened, and the rapid detection of Guang tangerine peel aging year can be realized.

Claims

1. A method for quickly detecting the aging year of tangerine peel, characterized in that: The following steps are involved: S1. Constructing a function model of tangerine peel aging years and tangerine peel physical and chemical index parameters; S2. Input the physical and chemical index parameter values ​​of the tangerine peel samples to be tested into the function model to obtain the aging year of the samples to be tested; The tangerine peel physical and chemical index parameters include pH value, conductivity and 420nm absorbance.

2. The method according to claim 1, characterized in that: The tangerine peel is Guangdong tangerine peel.

3. The method according to claim 1, characterized in that: The aging method of the tangerine peel is natural aging.

4. The method according to claim 1, characterized in that: The aging years of the tangerine peel are 1 to 12 years.

5. The method according to claim 1, characterized in that: The function model in step S1 is a multiple linear regression fitting equation.

6. The method according to claim 1, characterized in that: The tangerine peel physical and chemical indicators described in step S1 are obtained by measuring the tangerine peel water extract.

7. The method according to claim 6, characterized in that: The tangerine peel water extract is obtained by crushing the tangerine peel and then subjecting it to ultrasonic water extraction.

8. The method according to claim 7, characterized in that: The tangerine peel water extract is obtained by adding water to the tangerine peel at a mass ratio of 1:48-52 after crushing the tangerine peel, and then ultrasonically extracting the tangerine peel.

9. The method according to claim 1, characterized in that: The physicochemical index parameters of the dried tangerine peel in step S1 are pH value, conductivity and absorbance at 420 nm; or pH value, conductivity, absorbance at 420 nm, reducing sugar content, Fe 2+ concentration and starch content.

10. The method according to claim 9, characterized in that: The reducing sugar content is determined by 3,5-dinitrosalicylic acid colorimetry; Fe 2+ The concentration was determined by 1,10-phenanthroline spectrophotometry; the starch content was determined by anthrone colorimetry.

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