Camellia seed oil adulteration identification method

Abstract

The application discloses a camellia seed oil adulteration identification method, which comprises the following steps: adding sodium hydroxide methanol solution into a test tube, then adding a to-be-detected oil sample, and mixing; placing the mixture in 4-6 DEG C and oscillating to react, then taking upper solution for standby; selecting a chromatographic column and filling silica gel as a stationary phase, then adding the upper solution, and eluting with acetone-petroleum ether solution; collecting the eluent, adding dimethylamine ethanol solution, and stirring at 15-35 DEG C to obtain a mixed solution; adding chloroform into the mixed solution, oscillating in a shaker, and then standing; taking lower solution as a to-be-detected solution; adding conchiolin blue into the to-be-detected solution for detection; the to-be-detected solution with conchiolin blue can be heated, or the pH can be adjusted, or copper sulfate solution or iron sulfate solution can be slowly added; and whether the to-be-detected solution contains camellia seed oil is judged according to the color change of the to-be-detected solution. The application can quickly and accurately identify camellia seed oil in camellia seed oil, and solves the problem that camellia seed oil and camellia seed oil are difficult to identify.

Description

Technical Field

[0001] This invention belongs to the field of edible oil adulteration identification technology, specifically relating to a method for identifying adulterated camellia seed oil. Background Technology

[0002] Camellia seeds, also known as tea seeds ( Camellia oleifera Abel. Camellia oleifera is the fruit of a plant belonging to the genus Camellia in the family Theaceae. It is one of the world's four major woody oil-producing tree species and also a unique woody oil-producing tree species in my country. The oil extracted from camellia seeds is called camellia seed oil. The fatty acid composition of camellia seed oil is very similar to that of olive oil, with unsaturated fatty acids accounting for over 90%, earning it the reputation of "Oriental olive oil." Camellia seed oil production accounts for 8% of China's total edible vegetable oil production, making it one of the top ten best-selling edible vegetable oil categories in my country.

[0003] Tea seeds ( Camellia Sinensis O.Ktze Tea seeds are the fruit of the tea plant, a member of the Theaceae family. They are a byproduct of tea production, and the oil extracted from tea seeds is called tea seed oil.

[0004] Camellia seeds are round, oval, or rhomboid in shape, while tea seeds are mainly round. Some unscrupulous merchants, seeking exorbitant profits, pass off tea seeds as camellia seeds or mix tea seeds into camellia seeds in a certain proportion. Even worse, some mix cold-pressed tea seed oil into camellia seed oil in different proportions. Since tea trees and camellia trees are plants of the same order, family, and genus but different species, the resulting tea seed oil and camellia seed oil are very similar in appearance and color. Furthermore, the light flavor of tea seed oil makes it more difficult to detect, which not only harms the interests of consumers but also hinders the healthy development of the camellia oil industry. Summary of the Invention

[0005] To address the above shortcomings, this invention discloses a method for identifying adulterated camellia seed oil, which can quickly and accurately identify tea seed oil in camellia seed oil, thus solving the problem of difficulty in distinguishing between tea seed oil and camellia seed oil.

[0006] This invention is achieved using the following technical solution: A method for identifying adulteration in camellia seed oil, comprising the following steps: (1) Add sodium hydroxide methanol solution to a test tube, then add the oil sample to be tested and mix. Then place it at 4-6℃ and shake for 13-15 hours. Then take the upper layer solution for later use. (2) Select a 3cm×40cm chromatography column, fill the chromatography column with silica gel as the stationary phase, and then add 2-5g of the upper layer solution obtained in step (1) to the chromatography column and elute with acetone-petroleum ether solution; (3) Collect the eluent obtained after elution in step (2) and place it in a constant temperature reactor. Add dimethylamine ethanol solution and stir for 1 to 2 hours at a temperature of 15 to 35°C to obtain a mixed solution. (4) Take the mixture obtained in step (3) and put it in a test tube. Then add chloroform and mix. Then place it in a shaker and shake for 5 minutes. After standing, take the lower layer solution as the test solution and put it in a test tube for later use. (5) Take the test solution obtained in step (4), add chitin to the test solution. If the color of the test solution does not change significantly, the oil sample does not contain tea seed oil; if the color of the test solution turns blue, then process it in any of the following ways: Method A: Heat the test liquid to above 85℃. If the color of the test liquid changes from blue to orange or red, it indicates that the oil sample contains tea seed oil. Method B: Add pH adjuster to the test solution to adjust the pH value of the test solution to below 4. If the color of the test solution changes from blue to orange or red, it indicates that the oil sample contains tea seed oil. Method C: Slowly add copper sulfate solution or ferric sulfate solution to the test solution. If the blue color of the test solution becomes significantly lighter or turns red, it indicates that the oil sample contains tea seed oil.

[0007] This invention utilizes the difference in ester composition between camellia seed oil and tea seed oil. It identifies whether tea seed oil has been added to camellia seed oil by extracting and detecting the unique ester components in tea seed oil. Specifically, sodium hydroxide methanol solution is added to the oil sample to be tested for mixing and reaction, causing the unique ester components in tea seed oil to hydrolyze and yield hydrolysis products. Simultaneously, shaking treatment at 4-6℃ facilitates the hydrolysis of esters. After the reaction is complete, the mixture is allowed to stand to obtain a supernatant containing hydrolysis products. This supernatant is then added to a chromatography column and eluted with acetone-petroleum ether to separate the eluent containing hydrolysis products. Dimethylamine ethanol solution is then added to the eluent for treatment, followed by chloroform extraction to obtain... When a test solution containing hydrolysis products is added, chitosan blue will bind to the hydrolysis products, causing the test solution to change color. If the test solution does not change color, it indicates that no hydrolysis products corresponding to the esters of tea seed oil have been extracted and separated from the tea seed oil, thus indicating that the tea seed oil does not contain tea seed oil. If the test solution turns blue, it is highly likely that the test solution contains hydrolysis products. Then, by heating, adjusting the pH, and adding copper sulfate solution or ferric sulfate solution, the test solution is further treated. If the color of the test solution changes significantly, it can be clearly stated that the test solution contains hydrolysis products corresponding to the esters of tea seed oil. Therefore, it can be determined that the tea seed oil contains tea seed oil.

[0008] This invention involves adding dimethylamine ethanol solution to the eluent to promote the binding of the hydrolysis products to chitosan cyanin, causing a color change in the test solution and thus improving the accuracy of identification. Simultaneously, heating and lowering the pH value can disrupt the structure of the hydrolysis products, also causing a color change in the test solution. Adding copper sulfate or ferric sulfate solution to the test solution, along with the added Fe... 3+ and Cu 2+ It can significantly disrupt the structure of hydrolysis products, thereby causing the test solution to change color.

[0009] Furthermore, the sodium hydroxide methanol solution mentioned in step (1) is prepared by adding 0.02 to 0.03 mol of sodium hydroxide per 1 L of methanol. Controlling the concentration of sodium hydroxide is beneficial to promoting the ester hydrolysis of tea seed oil to obtain hydrolysis products, because the reaction is incomplete when the concentration is below 0.02 mol / L, but the isomerization of the hydrolysis products is severe when the concentration is above 0.03 mol / L.

[0010] Furthermore, the silica gel in step (2) has a particle size of 200-300 mesh; the acetone-petroleum ether solution is obtained by mixing acetone and petroleum ether, and the volume ratio of acetone to petroleum ether is 70:30.

[0011] Furthermore, the volume ratio of the sodium hydroxide methanol solution to the oil sample to be tested in step (1) is 50:1.

[0012] Furthermore, in step (2), the amount of silica gel filled into the chromatography column is 60-150g.

[0013] Furthermore, the dimethylamine ethanol solution mentioned in step (3) is obtained by adding dimethylamine to ethanol, and the volume ratio of dimethylamine to ethanol is 85:15.

[0014] Furthermore, the pH adjuster mentioned in step (5) is any one of citric acid, lactic acid, and acetic acid.

[0015] Furthermore, the Cu in the copper sulfate solution described in step (5) 2+ The concentration is (0.2–1.0 mmol / 100 mL), and the Fe in the ferric sulfate solution is... 3+ The concentration is (0.2~1.0 mmol / 100mL).

[0016] Compared with existing technologies, this technical solution has the following advantages: This invention identifies the unique components of tea seed oil by comparing the components of camellia seed oil and tea seed oil. Then, it separates these components into the eluent using column chromatography, followed by extraction with chloroform to obtain the test solution. Chitosan blue is added to the test solution, or treatment methods such as heating, pH adjustment, addition of copper sulfate, or addition of ferric sulfate are used. Observing the color change of the test solution allows for the determination of whether the oil sample contains tea seed oil. The detection limit for tea seed oil concentration is below 10%, achieving rapid and accurate identification of tea seed oil in camellia seed oil. This solves the problem of difficulty in distinguishing between tea seed oil and camellia seed oil, which is beneficial for standardizing the camellia oil product market and promoting the healthy development of the camellia oil industry. Attached Figure Description

[0017] Figure 1 These are test images of the oil sample described in Experiment Example 1 after processing and the addition of chitosan blue.

[0018] Figure 2 These are partial sample test images of oil sample A described in Experiment Example 1.

[0019] Figure 3 These are partial sample test images of oil sample B described in Experiment Example 1. Detailed Implementation

[0020] The present invention is further illustrated by the following examples, but these are not intended to limit the invention. Specific experimental conditions and methods not specified in the following examples are generally conventional methods well known to those skilled in the art.

[0021] Example 1: A method for identifying adulteration in camellia seed oil, comprising the following steps: (1) Take sodium hydroxide methanol solution and add it to a test tube, then add the oil sample to be tested and mix. The volume ratio of sodium hydroxide solution to oil sample to be tested is 50:1. Then place it at 4.5℃ and shake for 14h. Then take the upper layer solution for later use. The sodium hydroxide methanol solution is prepared according to the ratio of 0.025mol sodium hydroxide per 1L of methanol. (2) Select a 3cm×40cm chromatography column, fill the chromatography column with silica gel as the stationary phase, and fill the chromatography column with 60g of silica gel. Then add 2g of the upper layer solution obtained in step (1) to the chromatography column and elute with acetone-petroleum ether solution. The particle size of the silica gel is 250 mesh. The acetone-petroleum ether solution is obtained by mixing acetone and petroleum ether, and the volume ratio of acetone to petroleum ether is 70:30. (3) Collect the eluent obtained after elution in step (2) and place it in a constant temperature reactor. Add dimethylamine ethanol solution and stir for 1 hour at a temperature of 15°C to obtain a mixed solution. The dimethylamine ethanol solution is obtained by adding dimethylamine to ethanol, and the volume ratio of dimethylamine to ethanol is 85:15. (4) Take the mixture obtained in step (3) and put it in a test tube. Then add chloroform and mix. Then place it in a shaker and shake for 5 minutes. After standing, take the lower layer solution as the test solution and put it in a test tube. (5) Take the test solution obtained in step (4) and add chitin to the test solution. If the color of the test solution does not change significantly, the oil sample does not contain tea seed oil. If the color of the test solution turns blue, heat the test solution to 90°C. If the color of the test solution changes from blue to orange or red, it indicates that the oil sample contains tea seed oil.

[0022] Example 2: A method for identifying adulteration in camellia seed oil, comprising the following steps: (1) Take sodium hydroxide methanol solution and add it to a test tube, then add the oil sample to be tested and mix. The volume ratio of sodium hydroxide solution to oil sample to be tested is 50:1. Then place it at 5℃ and shake for 13.5h. Then take the upper layer solution for later use. The sodium hydroxide methanol solution is prepared according to the ratio of 0.02mol sodium hydroxide per 1L of methanol. (2) Select a 3cm×40cm chromatography column, fill the chromatography column with silica gel as the stationary phase, and fill the chromatography column with 150g of silica gel. Then add 5g of the upper layer solution obtained in step (1) to the chromatography column and elute with acetone-petroleum ether solution. The particle size of the silica gel is 200 mesh. The acetone-petroleum ether solution is obtained by mixing acetone and petroleum ether, and the volume ratio of acetone to petroleum ether is 70:30. (3) Collect the eluent obtained after elution in step (2) and place it in a constant temperature reactor. Add dimethylamine ethanol solution and stir for 2 hours at a temperature of 35°C to obtain a mixed solution. The dimethylamine ethanol solution is obtained by adding dimethylamine to ethanol, and the volume ratio of dimethylamine to ethanol is 85:15. (4) Take the mixture obtained in step (3) and put it in a test tube. Then add chloroform and mix. Then place it in a shaker and shake for 5 minutes. After standing, take the lower layer solution as the test solution and put it in a test tube. (5) Take the test solution obtained in step (4) and add chitin to the test solution. If the color of the test solution does not change significantly, the oil sample does not contain tea seed oil. If the color of the test solution turns blue, add a pH adjuster to adjust the pH value of the test solution to 2. The pH adjuster is citric acid. If the color of the test solution changes from blue to orange or red, it indicates that the oil sample contains tea seed oil.

[0023] Example 3: A method for identifying adulteration in camellia seed oil, comprising the following steps: (1) Take sodium hydroxide methanol solution and add it to a test tube, then add the oil sample to be tested and mix. The volume ratio of sodium hydroxide solution to oil sample to be tested is 50:1. Then place it at 5.5℃ and shake for 14h. Then take the upper layer solution for later use. The sodium hydroxide methanol solution is prepared according to the ratio of 0.03mol sodium hydroxide per 1L of methanol. (2) Select a 3cm×40cm chromatography column, fill the chromatography column with silica gel as the stationary phase, and fill the chromatography column with 75g of silica gel. Then add 2.5g of the upper layer solution obtained in step (1) to the chromatography column and elute with acetone-petroleum ether solution. The particle size of the silica gel is 300 mesh. The acetone-petroleum ether solution is obtained by mixing acetone and petroleum ether, and the volume ratio of acetone to petroleum ether is 70:30. (3) Collect the eluent obtained after elution in step (2) and place it in a constant temperature reactor. Add dimethylamine ethanol solution and stir for 1.5 h at a temperature of 25°C to obtain a mixed solution. The dimethylamine ethanol solution is obtained by adding dimethylamine to ethanol, and the volume ratio of dimethylamine to ethanol is 85:15. (4) Take the mixture obtained in step (3) and put it in a test tube. Then add chloroform and mix. Then place it in a shaker and shake for 5 minutes. After standing, take the lower layer solution as the test solution and put it in a test tube. (5) Take the test solution obtained in step (4) and add chitin to the test solution. If the color of the test solution does not change significantly, the oil sample does not contain tea seed oil. If the color of the test solution turns blue, add a pH adjuster to adjust the pH value of the test solution to 3. The pH adjuster is lactic acid. If the color of the test solution changes from blue to orange or red, it indicates that the oil sample contains tea seed oil.

[0024] Example 4: A method for identifying adulteration in camellia seed oil, comprising the following steps: (1) Add sodium hydroxide methanol solution to a test tube, then add the oil sample to be tested and mix. The volume ratio of sodium hydroxide solution to oil sample to be tested is 50:1. Then place it at 4℃ and shake for 15h. Then take the upper layer solution for later use. The sodium hydroxide methanol solution is prepared according to the ratio of 0.025mol sodium hydroxide per 1L of methanol. (2) Select a 3cm×40cm chromatography column, fill the chromatography column with silica gel as the stationary phase, and fill the chromatography column with 100g of silica gel. Then add 3g of the upper layer solution obtained in step (1) to the chromatography column and elute with acetone-petroleum ether solution. The particle size of the silica gel is 250 mesh. The acetone-petroleum ether solution is obtained by mixing acetone and petroleum ether, and the volume ratio of acetone to petroleum ether is 70:30. (3) Collect the eluent obtained after elution in step (2) and place it in a constant temperature reactor. Add dimethylamine ethanol solution and stir for 1.5 h at a temperature of 20°C to obtain a mixed solution. The dimethylamine ethanol solution is obtained by adding dimethylamine to ethanol. The volume ratio of dimethylamine to ethanol is 85:15. (4) Take the mixture obtained in step (3) and put it in a test tube. Then add chloroform and mix. Then place it in a shaker and shake for 5 minutes. After standing, take the lower layer solution as the test solution and put it in a test tube. (5) Take the test solution obtained in step (4) and add chitin to the test solution. If the color of the test solution does not change significantly, the oil sample does not contain tea seed oil. If the color of the test solution turns blue, heat the test solution to 95°C. If the color of the test solution changes from blue to orange or red, it indicates that the oil sample contains tea seed oil.

[0025] Example 5: A method for identifying adulteration in camellia seed oil, comprising the following steps: (1) Add sodium hydroxide methanol solution to a test tube, then add the oil sample to be tested and mix. The volume ratio of the sodium hydroxide solution to the oil sample to be tested is 50:1. Then place it at 5℃ and shake for 14h. Then take the upper layer solution for later use. The sodium hydroxide methanol solution is prepared according to the ratio of 0.02mol sodium hydroxide per 1L of methanol. (2) Select a 3cm×40cm chromatography column, fill the chromatography column with silica gel as the stationary phase, and fill the chromatography column with 110g of silica gel. Then add 3.5g of the upper layer solution obtained in step (1) to the chromatography column and elute with acetone-petroleum ether solution. The particle size of the silica gel is 200 mesh. The acetone-petroleum ether solution is obtained by mixing acetone and petroleum ether, and the volume ratio of acetone to petroleum ether is 70:30. (3) Collect the eluent obtained after elution in step (2) and place it in a constant temperature reactor. Add dimethylamine ethanol solution and stir for 1 hour at a temperature of 25°C to obtain a mixed solution. The dimethylamine ethanol solution is obtained by adding dimethylamine to ethanol, and the volume ratio of dimethylamine to ethanol is 85:15. (4) Take the mixture obtained in step (3) and put it in a test tube. Then add chloroform and mix. Then place it in a shaker and shake for 5 minutes. After standing, take the lower layer solution as the test solution and put it in a test tube. (5) Take the test solution obtained in step (4), add chitin to the test solution. If the color of the test solution does not change significantly, the oil sample does not contain tea seed oil; if the color of the test solution turns blue, slowly add copper sulfate solution to the test solution. The copper sulfate solution contains Cu 2+ If the blue color of the test solution becomes significantly lighter or turns red when the concentration is 0.5 mmol / 100 mL, it indicates that the oil sample contains tea seed oil.

[0026] Example 6: A method for identifying adulteration in camellia seed oil, comprising the following steps: (1) Add sodium hydroxide methanol solution to a test tube, then add the oil sample to be tested and mix. The volume ratio of sodium hydroxide solution to oil sample to be tested is 50:1. Then place it at 6°C and shake for 13 hours. Then take the upper layer solution for later use. The sodium hydroxide methanol solution is prepared according to the ratio of 0.03 mol of sodium hydroxide added to 1L of methanol. (2) Select a 3cm×40cm chromatography column, fill the chromatography column with silica gel as the stationary phase, and fill the chromatography column with 130g of silica gel. Then add 4g of the upper layer solution obtained in step (1) to the chromatography column and elute with acetone-petroleum ether solution. The particle size of the silica gel is 300 mesh. The acetone-petroleum ether solution is obtained by mixing acetone and petroleum ether, and the volume ratio of acetone to petroleum ether is 70:30. (3) Collect the eluent obtained after elution in step (2) and place it in a constant temperature reactor. Add dimethylamine ethanol solution and stir for 2 hours at a temperature of 25°C to obtain a mixed solution. The dimethylamine ethanol solution is obtained by adding dimethylamine to ethanol, and the volume ratio of dimethylamine to ethanol is 85:15. (4) Take the mixture obtained in step (3) and put it in a test tube. Then add chloroform and mix. Then place it in a shaker and shake for 5 minutes. After standing, take the lower layer solution as the test solution and put it in a test tube. (5) Take the test solution obtained in step (4), add chitosan blue to the test solution. If the color of the test solution does not change significantly, the oil sample does not contain tea seed oil; if the color of the test solution turns blue, slowly add ferric sulfate solution to the test solution. The Fe in the ferric sulfate solution... 3+ If the blue color of the test solution becomes significantly lighter or turns red when the concentration is 1.0 mmol / 100 mL, it indicates that the oil sample contains tea seed oil.

[0027] Example 7: A method for identifying adulteration in camellia seed oil, comprising the following steps: (1) Take sodium hydroxide methanol solution and add it to a test tube, then add the oil sample to be tested and mix. The volume ratio of sodium hydroxide solution to oil sample to be tested is 50:1. Then place it at 5℃ and shake for 14h. Then take the upper layer solution for later use. The sodium hydroxide methanol solution is prepared according to the ratio of 0.02mol sodium hydroxide per 1L of methanol. (2) Select a 3cm×40cm chromatography column, fill the chromatography column with silica gel as the stationary phase, and fill the chromatography column with 75g of silica gel. Then add 2.5g of the upper layer solution obtained in step (1) to the chromatography column and elute with acetone-petroleum ether solution. The particle size of the silica gel is 300 mesh. The acetone-petroleum ether solution is obtained by mixing acetone and petroleum ether, and the volume ratio of acetone to petroleum ether is 70:30. (3) Collect the eluent obtained after elution in step (3) and place it in a constant temperature reactor. Add dimethylamine ethanol solution and stir for 1.5 h at a temperature of 25°C to obtain a mixed solution. The dimethylamine ethanol solution is obtained by adding dimethylamine to ethanol, and the volume ratio of dimethylamine to ethanol is 85:15. (4) Take the mixture obtained in step (3) and put it in a test tube. Then add chloroform and mix. Then place it in a shaker and shake for 5 minutes. After standing, take the lower layer solution as the test solution and put it in a test tube. (5) Take the test solution obtained in step (4) and add chitin to the test solution. If the color of the test solution does not change significantly, the oil sample does not contain tea seed oil. If the color of the test solution turns blue, add a pH adjuster to adjust the pH value of the test solution to 3. The pH adjuster is acetic acid. If the color of the test solution changes from blue to orange or red, it indicates that the oil sample contains tea seed oil.

[0028] Comparative Example 1: The conventional method was used to identify whether camellia seed oil contained tea seed oil, specifically including the following steps: (1) Internal standard method: After the sample with internal standard is hydrolyzed and extracted with ether solution, it is saponified and methylated under alkaline conditions to generate fatty acid methyl esters. The content of fatty acid methyl esters is quantitatively determined by capillary column gas chromatography. The total fat, saturated fat (acid), monounsaturated fat (acid), and polyunsaturated fat (acid) content are calculated based on the content of various fatty acid methyl esters and conversion coefficients. (2) External standard method: After the fat in the sample is extracted by hydrolysis-ether solution, it is saponified and methylated under alkaline conditions to generate fatty acid methyl esters. The content of fatty acids is quantitatively determined by capillary column gas chromatography. (3) Normalization method: After the sample is extracted with hydrolysis-ether solution to remove fat, it is saponified and methylated under alkaline conditions to generate fatty acid methyl esters. The fatty acid percentage is quantitatively determined by capillary column gas chromatography and area normalization method.

[0029] The method described in Comparative Example 1 for distinguishing between camellia seed oil and tea seed oil involves detecting fatty acid methyl esters in the sample and calculating the content of total fat, saturated fat (acid), monounsaturated fat (acid), and polyunsaturated fat (acid). When the oleic acid content in camellia seed oil is higher than 70% and the oleic acid content in tea seed oil is higher than 50%, it is impossible to distinguish whether tea seed oil has been added. In other words, the existing conventional method cannot accurately identify adulteration when the amount of tea seed oil added is small.

[0030] Experimental Example 1: 920 mL of camellia seed oil and 80 mL of tea seed oil were evenly mixed to prepare test oil sample A. 800 mL of camellia seed oil and 200 mL of tea seed oil were evenly mixed to prepare test oil sample B. 10 mL of each of the test oil samples A, B, and pure camellia seed oil were transferred and tested according to the methods described in Examples 1-7 and Comparative Example 1. The test results are shown in Table 1 and... Figures 1-3 .

[0031] Table 1 Results of oil samples tested using different methods Example 1 The color of the test solution changed from blue to orange. The color of the test solution changed from blue to red. The color of the test solution did not change significantly. Example 2 The color of the test solution changed from blue to orange. The color of the test solution changed from blue to red. The color of the test solution did not change significantly. Example 3 The color of the test solution changed from blue to orange. The color of the test solution changed from blue to red. The color of the test solution did not change significantly. Example 4 The color of the test solution changed from blue to orange. The color of the test solution changed from blue to red. The color of the test solution did not change significantly. Example 5 The color of the test solution changed from blue to orange. The color of the test solution changed from blue to red. The color of the test solution did not change significantly. Example 6 The color of the test solution changed from blue to orange. The color of the test solution changed from blue to red. The color of the test solution did not change significantly. Example 7 The color of the test solution changed from blue to orange. The color of the test solution changed from blue to red. The color of the test solution did not change significantly. Experimental Example 2: Camellia seed oil was mixed with different amounts of tea seed oil to obtain test oil samples C with different tea seed oil contents. Then, the samples were tested according to the methods described in Examples 1, 3, 5, and 6. The test results are shown in Table 2.

[0032] Table 2 3 The color of the test solution changed from blue to orange. The color of the test solution changed from blue to orange. The color of the test solution changed from blue to orange. The color of the test solution changed from blue to orange. 5 The color of the test solution changed from blue to orange. The color of the test solution changed from blue to orange. The color of the test solution changed from blue to orange. The color of the test solution changed from blue to orange. 8 The color of the test solution changed from blue to orange. The color of the test solution changed from blue to orange. The color of the test solution changed from blue to orange. The color of the test solution changed from blue to orange. 10 The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. 12 The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. 15 The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. 18 The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. 20 The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. 25 The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. 30 The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. The color of the test solution changed from blue to red. As can be seen from the above data, the method of the present invention can effectively identify tea seed oil components in tea seed oil, and its detection limit for tea seed oil concentration is below 10%.

[0033] Experimental Example 3: 900 mL of camellia seed oil and 100 mL of tea seed oil were mixed evenly to obtain test oil sample D. Then, the oil sample was tested according to the method described in Example 3. The oil sample was shaken and reacted at 1℃, 4℃, 6℃, 10℃, 15℃ and room temperature, respectively. Then, it was processed according to the steps. The test results are shown in Table 3.

[0034] 1 The color of the test solution changed from blue to red. 4 The color of the test solution changed from blue to red. 6 The color of the test solution changed from blue to red. 10 The color of the test solution changed from blue to orange. 15 The color of the test solution did not change significantly. room temperature The color of the test solution did not change significantly. As can be seen from the above data, lowering the mixing temperature of sodium hydroxide methanol solution and the oil sample to be tested according to the method of the present invention is beneficial to the extraction and separation of unique components in tea seed oil, and improves the sensitivity of tea seed oil identification.

[0035] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for identifying adulteration in camellia seed oil, characterized in that: Includes the following steps: (1) Add sodium hydroxide methanol solution to a test tube, then add the oil sample to be tested and mix. Then place it at 4-6℃ and shake for 13-15 hours. Then take the upper layer solution for later use. (2) Select a 3cm×40cm chromatography column, fill the chromatography column with silica gel as the stationary phase, and then add 2-5g of the upper layer solution obtained in step (1) to the chromatography column and elute with acetone-petroleum ether solution; (3) Collect the eluent obtained after elution in step (2) and place it in a constant temperature reactor. Add dimethylamine ethanol solution and stir for 1 to 2 hours at a temperature of 15 to 35°C to obtain a mixed solution. (4) Take the mixture obtained in step (3) and put it in a test tube. Then add chloroform and mix. Then place it in a shaker and shake for 5 minutes. After standing, take the lower layer solution as the test solution and put it in a test tube for later use. (5) Take the test solution obtained in step (4), add chitin to the test solution. If the color of the test solution does not change significantly, the oil sample does not contain tea seed oil; if the color of the test solution turns blue, then process it in any of the following ways: Method A: Heat the test liquid to above 85℃. If the color of the test liquid changes from blue to orange or red, it indicates that the oil sample contains tea seed oil. Method B: Add pH adjuster to the test solution to adjust the pH value of the test solution to below 4. If the color of the test solution changes from blue to orange or red, it indicates that the oil sample contains tea seed oil. Method C: Slowly add copper sulfate solution or ferric sulfate solution to the test solution. If the blue color of the test solution becomes significantly lighter or turns red, it indicates that the oil sample contains tea seed oil.

2. The method for identifying adulteration of camellia seed oil according to claim 1, characterized in that: The sodium hydroxide methanol solution mentioned in step (1) is prepared by adding 0.02 to 0.03 mol of sodium hydroxide per 1L of methanol.

3. The method for identifying adulteration of camellia seed oil according to claim 1, characterized in that: The silica gel in step (2) has a particle size of 200-300 mesh; the acetone-petroleum ether solution is obtained by mixing acetone and petroleum ether, and the volume ratio of acetone to petroleum ether is 70:

30.

4. The method for identifying adulteration of camellia seed oil according to claim 1, characterized in that: The volume ratio of the sodium hydroxide methanol solution to the oil sample to be tested in step (1) is 50:

1.

5. The method for identifying adulteration of camellia seed oil according to claim 1, characterized in that: In step (2), the amount of silica gel filled into the chromatography column is 60-150g.

6. The method for identifying adulteration of camellia seed oil according to claim 1, characterized in that: The dimethylamine ethanol solution mentioned in step (3) is obtained by adding dimethylamine to ethanol, and the volume ratio of dimethylamine to ethanol is 85:

15.

7. The method for identifying adulteration of camellia seed oil according to claim 1, characterized in that: The pH adjuster mentioned in step (5) is any one of citric acid, lactic acid, and acetic acid.

8. The method for identifying adulteration of camellia seed oil according to claim 1, characterized in that: Cu in the copper sulfate solution described in step (5) 2+ The concentration is (0.2–1.0 mmol / 100 mL), and the Fe in the ferric sulfate solution is... 3+ The concentration is (0.2~1.0 mmol / 100mL).

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