A method for identifying the authenticity of concentrated fruit and vegetable juice
By measuring the stable oxygen isotope ratio of water in concentrated fruit and vegetable juice and building a database, the problem of difficult to identify counterfeit and inferior products of concentrated fruit and vegetable juice in the prior art is solved, and the accurate identification of the authenticity of concentrated fruit and vegetable juice is achieved, and the interests of manufacturers and consumers are protected.
Patent Information
- Application Number
- CN202211640384.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-20
- Publication Date
- 2025-04-11
- Estimated Expiration
- 2042-12-20
AI Technical Summary
The prior art is difficult to effectively identify counterfeit and inferior products in concentrated fruit and vegetable juices, especially because concentrated fruit and vegetable juices have similar physical characteristics to sugar raw materials such as fruit and glucose syrup, which leads to difficulty in detection.
Using stable isotope technology, a database of this feature is constructed by measuring the stable oxygen isotope ratio of water in concentrated fruit and vegetable juices, and using this as a basis to identify the authenticity of concentrated fruit and vegetable juices.
It has achieved accurate identification of the authenticity of concentrated fruit and vegetable juice, which is simple and fast, with low cost, and can effectively protect the interests of manufacturers and consumers.
Abstract
Description
Technical Field
[0001] The invention belongs to the field of food detection and relates to a method for identifying the authenticity of concentrated fruit and vegetable juice. Background Art
[0002] In recent years, with the improvement of people's living standards and the pursuit of healthy life, fruit juice / juice-type beverages with nutrition and health as selling points have become more and more popular. Fruit juice beverages are not only rich in flavor and good taste, but also rich in organic acids and dietary fiber. Among them, fruit cellulose is the main component of plant cell walls. Although it is not a nutrient, it absorbs water and swells after being ingested by the human body. It can absorb harmful components in food, stimulate gastrointestinal motility, help consumption, speed up excretion in the body, shorten the retention time of harmful substances in the body, and ultimately achieve the purpose of preventing gastrointestinal diseases. It has positive significance for preventing digestive tract cancer. Therefore, cellulose is called the seventh nutrient after protein, carbohydrates, fat, inorganic salts, vitamins and trace elements by nutritionists.
[0003] In recent years, the output of fruit and vegetable juice in my country has stabilized at around 15 million tons. In the first half of 2021, the output of fruit juice and vegetable beverages in China was 8.256 million tons, a year-on-year increase of 17.32%. At present, my country's fruit juice consumption market is very large. Considering our growing consumption level, there is still a huge room for development in my country's demand for fruit juice in the future. Since freshly squeezed juice / NFC juice has just started, the market is mainly dominated by low-alcohol juice, medium-alcohol juice and 100% reconstituted juice, and the raw materials for the production of these categories are all concentrated fruit and vegetable juice. However, since concentrated fruit and vegetable juice has similar physical properties to sugar raw materials such as fructose syrup, the problem of counterfeiting concentrated fruit and vegetable juice with sucrose or fructose syrup occurs from time to time, which seriously damages the interests of downstream fruit juice beverage manufacturers. The "concentrated fruit and vegetable juice" they purchase may be counterfeit and inferior products. In the absence of detection methods, not only do they spend a high price to buy low-quality products, but using them in the production of fruit juice beverages further damages the interests of consumers.
[0004] Stable isotope technology has important application value in food adulteration detection and authenticity identification. It is different from other technologies such as chromatography and mass spectrometry in that it studies not trace substances, but the characteristics and differences of constant substances (such as organic matter containing carbon and hydrogen elements). The prior art discloses that carbon isotope technology can be used to detect carbon-4 plant sugars in concentrated fruit and vegetable juices, but this method is limited to detecting carbon-4 plant sugars such as cane sugar and corn syrup. Substances such as beets and nectar plants belong to carbon-3 plants, and carbon isotope technology will lose its effect. Hydrogen isotope technology can be used to detect carbon-3 beet sugars in concentrated fruit and vegetable juices, but it is difficult to detect other carbon-3 plant sugars such as rice syrup and wheat syrup. Constant substances in concentrated fruit and vegetable juices are not only organic matter containing carbon and hydrogen elements, but water is also at a constant level. Although the water content is less than that of sugar organic matter, there is no difference in order of magnitude. Summary of the invention
[0005] The present invention proposes a method for identifying the authenticity of concentrated fruit and vegetable juice. Starting from the index characteristics of constant compounds, the stable oxygen isotope technology is used to accurately measure the stable oxygen isotope characteristics of water in the concentrated fruit and vegetable juice, and a database of the characteristics is constructed. Based on this, the authenticity of the concentrated fruit and vegetable juice is identified.
[0006] The present invention provides a method for identifying the authenticity of concentrated fruit and vegetable juice, comprising the following steps:
[0007] 1) adding an organic reagent to a real concentrated fruit and vegetable juice sample to obtain a real concentrated fruit and vegetable juice sample solution; determining the stable oxygen isotope ratio of water in the real concentrated fruit and vegetable juice sample solution, and constructing a database of stable oxygen isotope ratios of water in the real concentrated fruit and vegetable juice sample;
[0008] 2) adding an organic reagent to the concentrated fruit and vegetable juice sample to be tested to obtain a concentrated fruit and vegetable juice sample solution to be tested; and determining the stable oxygen isotope ratio of water in the concentrated fruit and vegetable juice sample to be tested;
[0009] 3) comparing the stable oxygen isotope ratio measurement result of water in the concentrated fruit and vegetable juice sample to be tested obtained in step 2) with the stable oxygen isotope ratio database of water in the real concentrated fruit and vegetable juice samples obtained in step 1); if the measurement result of the concentrated fruit and vegetable juice to be tested is less than the minimum value of the database, it is determined that the concentrated fruit and vegetable juice to be tested is not real concentrated fruit and vegetable juice.
[0010] Furthermore, in step 1) and step 2), the organic reagent is at least one of esters, alcohols, nitriles, ethers, and ketones;
[0011] Preferably, the organic reagent is an alcohol;
[0012] More preferably, the organic agent is ethanol.
[0013] Furthermore, in step 1) and step 2), the organic reagent is subjected to anhydrous treatment;
[0014] Preferably, the organic reagent is anhydrous by molecular sieve.
[0015] Further, in step 1), the mass ratio of the real concentrated fruit and vegetable juice sample to the organic reagent is 1:0.6-1;
[0016] Preferably, the mass ratio of the real concentrated fruit and vegetable juice sample to the organic reagent is 1:1;
[0017] In step 2), the mass ratio of the concentrated fruit and vegetable juice sample to be tested to the organic reagent is 1:0.6-1;
[0018] Preferably, the mass ratio of the concentrated fruit and vegetable juice sample to be tested to the organic reagent is 1:1.
[0019] Furthermore, in step 1) and step 2), a gas chromatography-isotope ratio mass spectrometer is used to measure the stable oxygen isotope ratio of water.
[0020] Furthermore, in step 3), the data in the database are obtained annually from similar concentrated fruit and vegetable juice samples across the country, with the number being at least 30.
[0021] Furthermore, the concentrated fruit and vegetable juice includes concentrated orange juice, concentrated apple juice, concentrated pear juice, concentrated peach juice, concentrated mango juice or concentrated carrot juice.
[0022] The present invention has the following advantages:
[0023] The method for identifying the authenticity of concentrated fruit and vegetable juice proposed by the present invention takes into account the low water content in concentrated fruit and vegetable juice, uses an organic solvent to dissolve and extract the water in the concentrated fruit and vegetable juice, under the action of an organic reagent, the water is fully contacted with carbon dioxide, and the stable oxygen isotope ratio of carbon dioxide is determined by a gas chromatography-stable isotope ratio mass spectrometry system, and finally the stable oxygen isotope ratio of water in the concentrated fruit and vegetable juice is obtained by calibration with a standard product, thereby achieving the determination of the oxygen isotope ratio of water in concentrated fruit and vegetable juice with very little water content. By analyzing the oxygen isotope characteristics of water in real concentrated fruit and vegetable juice and establishing a database, and then comparing the concentrated fruit and vegetable juice sample to be tested with the data in the database, the authenticity of the concentrated fruit and vegetable juice sample to be tested can be determined. The method is simple and fast, has low cost, and can accurately identify the authenticity of concentrated fruit and vegetable juice. DETAILED DESCRIPTION
[0024] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.
[0025] An embodiment of the present invention provides a method for identifying the authenticity of concentrated fruit and vegetable juice, comprising the following steps:
[0026] 1) adding an organic reagent to a real concentrated fruit and vegetable juice sample to obtain a real concentrated fruit and vegetable juice sample solution; determining the stable oxygen isotope ratio of water in the real concentrated fruit and vegetable juice sample solution, and constructing a database of stable oxygen isotope ratios of water in the real concentrated fruit and vegetable juice sample;
[0027] 2) adding an organic reagent to the concentrated fruit and vegetable juice sample to be tested to obtain a concentrated fruit and vegetable juice sample solution to be tested; and determining the stable oxygen isotope ratio of water in the concentrated fruit and vegetable juice sample to be tested;
[0028] 3) comparing the stable oxygen isotope ratio measurement result of water in the concentrated fruit and vegetable juice sample to be tested obtained in step 2) with the stable oxygen isotope ratio database of water in the real concentrated fruit and vegetable juice samples obtained in step 1); if the measurement result of the concentrated fruit and vegetable juice to be tested is less than the minimum value of the database, it is determined that the concentrated fruit and vegetable juice to be tested is not real concentrated fruit and vegetable juice.
[0029] In the embodiment of the present invention, no matter what kind of cheap sugar (sugar or syrup) is added when the concentrated fruit and vegetable juice is counterfeited, water will inevitably be added in order to meet the physical and chemical indicators of the concentrated fruit and vegetable juice. Therefore, the stable oxygen isotope difference of water in the concentrated fruit and vegetable juice can be used to identify the authenticity of the concentrated fruit and vegetable juice. However, since the water content in the concentrated fruit and vegetable juice is not as high as that in wine and fruit juice, it is difficult to use existing analytical techniques for sample analysis and characteristic research, so a method for accurately analyzing the stable oxygen isotope ratio of water in the concentrated fruit and vegetable juice is proposed, and the water in the concentrated fruit and vegetable juice is dissolved and extracted by an organic solvent, so that the water is fully contacted with carbon dioxide, and the stable oxygen isotope ratio of carbon dioxide is directly measured, and then calibrated by a standard product to obtain the stable oxygen isotope ratio of water. By establishing a database of real concentrated fruit and vegetable juice, the concentrated fruit and vegetable juice to be tested is compared with it, thereby achieving the purpose of distinguishing the authenticity of the concentrated fruit and vegetable juice.
[0030] It should be pointed out that concentrated fruit and vegetable juice is made by evaporating part of the water by concentrating the fruits and vegetables after they are squeezed into original juice. The water content of original fruit and vegetable juice is very high, usually between 80-85%, and the concentration operation can increase the solids in the original fruit and vegetable juice from 5-20% to 60-75%, greatly reducing the water content. Since concentrated fruit and vegetable juice has similar physical properties to sugar raw materials such as fructose syrup, the problem of counterfeiting concentrated fruit and vegetable juice with sucrose or fructose syrup occurs from time to time. The present invention effectively solves the application technical problem of the lack of a simple and rapid method for identifying the authenticity of concentrated fruit and vegetable juice in the field of adulteration detection / authenticity assurance of concentrated fruit and vegetable juice, and will promote the formation of a normal and orderly competition order in the domestic concentrated fruit and vegetable juice industry, put an end to the phenomenon of "bad money driving out good money", and at the same time protect the interests of downstream fruit and vegetable juice production companies and consumers.
[0031] Preferably, the concentrated fruit and vegetable juice comprises concentrated orange juice, concentrated apple juice, concentrated pear juice, concentrated peach juice, concentrated mango juice or concentrated carrot juice. 18 O) is significantly higher than the δ 18 O, so it can be detected by this method.
[0032] In the embodiment of the present invention, in step 1), a real concentrated fruit and vegetable juice sample is selected, dissolved with an organic reagent, and after the water is released from the viscous state, the mixture containing water and organic reagent is used as the research object, and the stable oxygen isotope ratio of water is measured to construct a database of the stable oxygen isotope ratio of water in raw honey. Among them, the real concentrated fruit and vegetable juice sample is a product without any illegal additives, and the constructed database is a real and valid database.
[0033] In the embodiment of the present invention, in step 2), the concentrated fruit and vegetable juice to be tested is dissolved with an organic reagent, and after the water is released from the viscous state, subsequent analysis is performed based on the water-organic reagent mixture to determine the stable oxygen isotope ratio of water.
[0034] In one embodiment of the present invention, in step 1) and step 2), the organic reagent is at least one of esters, alcohols, nitriles, ethers, and ketones. Preferably, the organic reagent is alcohol. More preferably, the organic reagent is ethanol.
[0035] In one embodiment of the present invention, in step 1) and step 2), the organic reagent is subjected to anhydrous treatment. Preferably, the organic reagent is subjected to anhydrous treatment using a molecular sieve.
[0036] In one embodiment of the present invention, in step 1), the mass ratio of the real concentrated fruit and vegetable juice sample to the organic reagent is 1:0.6-1. Preferably, the mass ratio of the real concentrated fruit and vegetable juice sample to the organic reagent is 1:1.
[0037] In one embodiment of the present invention, in step 2), the mass ratio of the concentrated fruit and vegetable juice sample to be tested to the organic reagent is 1:0.6-1. Preferably, the mass ratio of the concentrated fruit and vegetable juice sample to be tested to the organic reagent is 1:1.
[0038] In one embodiment of the present invention, in step 1) and step 2), a gas chromatography-isotope ratio mass spectrometer (GC-IRMS) is used to measure the stable oxygen isotope ratio of water. The measurement methods of step 1) and step 2) are the same.
[0039] Specifically, taking step 2) as an example, step 2) specifically includes:
[0040] A) adding an organic reagent to the concentrated fruit and vegetable juice sample to be tested, mixing and letting stand, and taking the upper layer of liquid to obtain a solution to be tested;
[0041] B) placing the test solution obtained in step A) in a bottle, sealing it, replacing the air in the bottle with high-purity carbon dioxide gas, and then placing the bottle containing the test solution and high-purity carbon dioxide under constant temperature conditions to react to obtain a reaction solution;
[0042] C) Using a gas chromatography-stable isotope ratio mass spectrometry system, after determining the stable oxygen isotope ratio of carbon dioxide in the reaction solution, the stable oxygen isotope ratio of water in the concentrated fruit and vegetable juice sample to be measured is obtained by calibration with a standard substance.
[0043] Among them, in step C), the standard calibration specifically includes: selecting standard water (stable oxygen isotope ratio is known), adding an organic reagent to the water to obtain a standard solution to be tested; placing the standard solution to be tested in a bottle, sealing it, replacing the air in the bottle with high-purity carbon dioxide gas, reacting under constant temperature conditions, using a gas chromatography-stable isotope ratio mass spectrometry system, determining the stable oxygen isotope ratio of carbon dioxide in the standard reaction solution, and establishing a standard curve for water working standard between water and carbon dioxide; in combination with the above standard curve, according to the stable oxygen isotope ratio of carbon dioxide in the reaction solution, the stable oxygen isotope ratio of water in the reaction solution can be calculated.
[0044] The determination conditions of the standard solution to be tested are the same as those of the reaction solution.
[0045] In step B), the replacement time is 1 to 20 minutes, the reaction temperature is 10 to 100° C. under constant temperature conditions, and the reaction time is 4 to 48 hours under constant temperature conditions.
[0046] In the embodiment of the present invention, step 3) in other words, if the test result of the concentrated fruit and vegetable juice sample is within the distribution range of the database, it is determined that the concentrated fruit and vegetable juice sample is a real concentrated fruit and vegetable juice.
[0047] In one embodiment of the present invention, in step 3), the data in the database are obtained from similar concentrated fruit and vegetable juice samples across the country every year, and the number is at least 30.
[0048] The present invention will be described in detail below with reference to embodiments.
[0049] Example 1 Authenticity Identification of Concentrated Apple Juice Samples
[0050] a) Collect control samples: Collect pure, additive-free concentrated apple juice (42) from production companies in Shanxi, Shaanxi, Gansu, Yunnan, and Shandong, China, and record the sampling time and location;
[0051] b) Obtaining samples to be tested: registering detailed information of three concentrated apple juices to be tested, which are divided into sample 1, sample 2 and sample 3;
[0052] c) Take 3 g of sample from each control sample and the sample to be tested, and add 2.4 g of ethanol (add 10 g of activated The molecular sieve is dissolved in anhydrous ethanol and mixed evenly, and then the mixture is allowed to stand, and the liquid is taken for testing;
[0053] d) Pour the solution obtained in c) into a crimp-top headspace injection bottle, seal it with a crimp cap, insert a gas guide needle, fill it with high-purity CO2 and exhaust all the air, and then remove the gas guide needle;
[0054] e) Place the headspace bottle in d) at a constant temperature of 25°C and shake for more than 8 hours.
[0055] f) taking the headspace injection bottle after oscillation for 8 hours in e), collecting the gas in the headspace of the headspace injection bottle, injecting it into the GC-IRMS system, and determining the stable oxygen isotope ratio of carbon dioxide;
[0056] g) According to the PIT (identical treatment) principle of stable isotope analysis and testing [Werner RA, Brand WA. Referencing strategies and techniques in stable isotope ratio analysis. Rapid Commun Mass Spectrom. 2001; 15(7): 501-19. doi: 10.1002 / rcm.258. PMID: 11268135.], the stable isotope ratio of carbon dioxide was calibrated with a standard substance to obtain the stable oxygen isotope ratio of water in pure, additive-free concentrated apple juice.
[0057] The stable oxygen isotope ratio (δ 18 O) value distribution range is -1.44‰~3.91‰;
[0058] The δ in water of sample 1 was measured 18 O value is -5.11‰, and the δ 18 The O value was -0.82‰, and the δ18O value in the water of sample three was measured to be 2.04‰.
[0059] h) Compare the stable oxygen isotope ratios (δ 18 O) It can be seen that:
[0060] δ of sample 1 18 The O value is less than the minimum value in the database, so the product can be determined to be fake concentrated apple juice;
[0061] δ of sample 2 18 The O value conforms to the distribution range of the database, and the product can be determined to be true concentrated apple juice;
[0062] δ of sample 3 18 The O value is consistent with the distribution range of the database, and the product can be determined to be true concentrated apple juice.
[0063] Test Example 1 Verify the accuracy of the detection method of the present invention
[0064] a) Select a concentrated apple juice (No. 1#) as the research object, and measure its soluble solid content to be 66.3%. Select beet sugar and tap water as the research objects, and prepare a syrup (No. 2#) having the same soluble solid content as the concentrated apple juice No. 1;
[0065] b) adding syrup to concentrated apple juice at a mass ratio of 2:8, 4:6, 6:4 and 8:2, thereby obtaining simulated samples with syrup mass ratios of 20%, 40%, 60% and 80%, which are numbered 3#, 4#, 5# and 6# respectively;
[0066] c) Take 3g of each of the above 6 samples, add 3g of ethanol and mix thoroughly, let stand and take the upper solution for later use;
[0067] d) Pour the solution obtained in c) into a crimp-top headspace injection bottle, seal it with a crimp cap, insert a gas guide needle, fill it with high-purity CO2 and exhaust all the air, and then remove the gas guide needle;
[0068] e) Place the headspace bottle in d) at a constant temperature of 25°C and shake for more than 8 hours.
[0069] f) taking the headspace injection bottle after oscillation for 8 hours in e), collecting the gas in the headspace of the headspace injection bottle, injecting it into the GC-IRMS system, and determining the stable oxygen isotope ratio of carbon dioxide;
[0070] g) According to the PIT (identical treatment) principle of stable isotope analysis and testing, the stable isotope ratio of carbon dioxide was calibrated with a standard substance to obtain the stable oxygen isotope ratio of water in each sample. The results are shown in Table 1.
[0071] Table 1 δ in water of each sample 18 O value (‰)
[0072] Sample No. 1# 2# 3# 4# 5# 6# Measured value 0.63 -8.11 -0.95 -3.15 -4.62 -6.62 Predicted value - - -1.12 -2.87 -4.61 -6.36 difference - - -0.17 0.28 0.01 0.26
[0073] As can be seen from Table 1, the absolute value of the difference between the predicted value and the measured value is <0.3‰, which meets the standard deviation requirements of the stable isotope ratio mass spectrometer oxygen isotope analysis test in water. The t-test analysis between the measured value and the predicted value shows that there is no significant difference between the two, and the measured value is linearly negatively correlated with the syrup blending ratio. Therefore, it can be shown that the method of the present invention can accurately analyze the stable oxygen isotope ratio of water in concentrated juice samples.
[0074] δ of water in the concentrated apple juice in Example 1 18 O database comparison, in this verification example, when the proportion of concentrated apple juice mixed with syrup is higher than 24%, the δ 18 The O value is smaller than the minimum value in the database, so it can be determined to be fake concentrated apple juice.
[0075] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for identifying the authenticity of concentrated fruit and vegetable juice, characterized in that: The steps include: 1) adding an organic reagent to a real concentrated fruit and vegetable juice sample to obtain a real concentrated fruit and vegetable juice sample solution; determining the stable oxygen isotope ratio of water in the real concentrated fruit and vegetable juice sample solution, and constructing a database of stable oxygen isotope ratios of water in real concentrated fruit and vegetable juice samples; wherein the mass ratio of the real concentrated fruit and vegetable juice sample to the organic reagent is 1:1; 2) adding an organic reagent to the concentrated fruit and vegetable juice sample to be tested to obtain a concentrated fruit and vegetable juice sample solution to be tested; determining the stable oxygen isotope ratio of water in the concentrated fruit and vegetable juice sample to be tested; wherein the mass ratio of the concentrated fruit and vegetable juice sample to be tested to the organic reagent is 1:1; 3) comparing the stable oxygen isotope ratio determination result of water in the concentrated fruit and vegetable juice sample to be tested obtained in step 2) with the stable oxygen isotope ratio database of water in the real concentrated fruit and vegetable juice sample obtained in step 1), if the determination result of the concentrated fruit and vegetable juice to be tested is less than the minimum value of the database, it is determined that the concentrated fruit and vegetable juice to be tested is not a real concentrated fruit and vegetable juice; Wherein, in step 1) and step 2), the organic reagent is ethanol, and the stable oxygen isotope ratio of water is determined using a gas chromatography-isotope ratio mass spectrometer; step 2) specifically comprises: A) adding an organic reagent to the concentrated fruit and vegetable juice sample to be tested, mixing and letting stand, and taking the upper layer of liquid to obtain a solution to be tested; B) placing the test solution obtained in step A) in a bottle, sealing it, replacing the air in the bottle with high-purity carbon dioxide gas, and then placing the bottle containing the test solution and high-purity carbon dioxide under constant temperature conditions to react to obtain a reaction solution; C) Using a gas chromatography-stable isotope ratio mass spectrometry system, after determining the stable oxygen isotope ratio of carbon dioxide in the reaction solution, the stable oxygen isotope ratio of water in the concentrated fruit and vegetable juice sample to be measured is obtained by calibration with a standard substance.
2. The method according to claim 1, characterized in that: In step 1) and step 2), the organic reagent is subjected to anhydrous treatment.
3. The method according to claim 1, characterized in that In step 1) and step 2), the organic reagent is anhydrous by molecular sieve.
4. The method according to claim 1, characterized in that In step 3), the data in the database are obtained from similar concentrated fruit and vegetable juice samples across the country every year, with a number of at least 30.
5. The method according to claim 1, characterized in that: Concentrated fruit and vegetable juices include concentrated orange juice, concentrated apple juice, concentrated pear juice, concentrated peach juice, concentrated mango juice or concentrated carrot juice.