Process for extracting carnosic acid and application of the extracted carnosic acid in vegetable oil

Abstract

The application relates to a process for extracting rosmarinic acid and application of the extracted rosmarinic acid in plant oil, S1, rosemary leaves are added into a mixed solution of ethanol and water with a first-stage concentration and are heated for extraction, after the extraction is completed, a first-stage extraction liquid is obtained; S2, the first-stage extraction liquid is concentrated, the concentrated liquid is subjected to plate-frame pressure filtration, the filter cake is washed with water, a filtrate and a filter residue are obtained; S3, the filtrate is subjected to extraction, the extraction liquid is concentrated, and after drying, a rosemary acid crude product is obtained; S4, the filter residue is subjected to reextraction with a mixed solution of ethanol and water with a second-stage concentration, after the reextraction is completed, filtration is carried out, a filtrate and a filter residue are obtained; the filter residue is a crude extract of ursolic acid and rosmarinic acid; S5, the filtrate is subjected to decolorization, and then is concentrated into a paste, after vacuum drying, a rosmarinic acid crude product is obtained. The method in the application can separate multiple active substances, obtain multiple crude products, improve the utilization rate of rosemary, and thus reduce the production cost.

Description

A process for extracting oxalic acid and its application in vegetable oils. Technical Field

[0001] This application relates to the technical field of drug extraction and application, and in particular to a process for extracting oxalic acid and the application of the extracted oxalic acid in vegetable oils. Background Technology

[0002] As people pay increasing attention to food safety, they are beginning to realize the potential harm of chemically synthesized antioxidants to humans. The pursuit of safe, non-toxic, and green functional antioxidants, advocating for a return to nature, has become mainstream worldwide. With the rapid advancement of science and technology, natural antioxidants have flourished, and people are increasingly favoring plant-derived antioxidants. Compared to chemically synthesized antioxidants, some natural antioxidants exhibit stronger antioxidant effects, thus attracting attention from the international academic community. Natural antioxidants have therefore become one of the most active areas in the antioxidant industry. Most natural antioxidants are polyphenols, among which dozens are widely used, including rosemary extract, vitamin E, bamboo leaf flavonoids, tea polyphenols, ginkgo extract, and licorice extract. The active ingredients in rosemary with antioxidant effects are diterpenoid phenolic compounds such as carnosic acid (CA), rosmarinic acid (RA), carnosine, and epirosmarinic acid, with carnosic acid possessing the strongest antioxidant capacity.

[0003] Sageric acid, a phenolic diterpenoid fat-soluble compound, with the molecular formula C 20 H 28 O4 has a relative molecular mass of 332.43. Sageric acid appears as a yellow-green powder and is highly soluble in chloroform and acetone. Due to its safety, high efficiency, and heat resistance, it is widely used in food additives, daily chemicals, animal feed, pharmaceuticals, and health products.

[0004] There are many extraction methods for rosmarinic acid from rosemary. Some existing improved methods mainly focus on increasing the purity of rosmarinic acid. Therefore, in actual extraction methods, other active extracts (such as rosmarinic acid and ursolic acid) are always sacrificed. However, in practical applications, crude rosmarinic acid has good anti-inflammatory and antioxidant effects, and other active substances also have other special functions. The price of raw material rosemary is not cheap, so it is very necessary to provide a method that can achieve the extraction of multiple active substances. Summary of the Invention

[0005] To improve the utilization rate of rosemary, this application provides a process for extracting carrageenan and the application of the extracted carrageenan in vegetable oils.

[0006] The first aspect is a process for extracting oxalic acid, which adopts the following technical solution:

[0007] A process for extracting oxalic acid from rat's tail includes the following steps:

[0008] S1. Rosemary leaves were added to a mixed solution of ethanol and water of the first-order concentration and heated for extraction. After extraction, the first-order extract was obtained.

[0009] S2. Concentrate the first-stage extract in step S1, filter the concentrate by plate and frame filter, wash the filter cake with water, and obtain filtrate and filter residue.

[0010] S3. Extract the filtrate from step S2, concentrate the extract, and dry it to obtain crude rosmarinic acid.

[0011] S4. The filter residue from step S2 is subjected to a second-stage concentration of ethanol and water for re-extraction. After the re-extraction is completed, the residue is filtered to obtain filtrate and filter residue. The filter residue is the crude extract of ursolic acid and caryophyllene.

[0012] S5: Decolorize the filtrate from step S4, then concentrate it into a paste, and vacuum dry it to obtain crude oxalic acid.

[0013] By adopting the above technical solution, this application first uses a first-stage extraction with ethanol (high concentration) and water, which allows for the large-scale release of rosemary active substances. The extract is then concentrated. During concentration, ethanol evaporates faster than water. Rosmarinic acid is water-soluble, while caryopsisic acid, caryopsisol, and ursolic acid are insoluble. Therefore, as evaporation proceeds, the ethanol content decreases significantly (to almost none). Caryopsisic acid, caryopsisol, and ursolic acid precipitate out during concentration, while rosmarinic acid remains in the liquid. Therefore, during plate filtration, the filtrate mainly contains rosmarinic acid, while the residue contains a mixture of caryopsisic acid, caryopsisol, and ursolic acid. A second-stage concentration of ethanol (lower concentration) and water is then used, taking advantage of the different solubilities of caryopsisic acid, caryopsisol, and ursolic acid in lower concentration ethanol. Caryopsisic acid has the highest solubility, while caryopsisol and ursolic acid have lower solubility. During the re-extraction, the filtrate mainly contains caryopsisic acid, while the residue mainly contains caryopsisol and ursolic acid, thus achieving the separation of caryopsisic acid. The extraction method in this application is relatively simple and can simultaneously extract multiple active substances from rosemary, improving the utilization rate of rosemary.

[0014] Preferably, in step S1, the mass concentration of ethanol in the first-stage concentration ethanol and water mixed solution is 85-95%; the number of extractions is 2-3 times, the extraction time is 0.5-1.5 hours, the extraction temperature is 65-75°C, and each extraction involves adding a mixed solution in an amount 8-12 times the mass of rosemary.

[0015] By adopting the above technical solution, the concentration of ethanol in the mixed solution used in this application must be greater than 85%. If the concentration is too low, caryophyllophenol and ursolic acid will be difficult to dissolve, which will lead to incomplete extraction. The number of extractions and the amount of extract added can be finely adjusted according to the actual situation, so as to ensure the extraction effect without wasting too much extract solution.

[0016] Preferably, in step S2, the concentration is carried out by vacuum decompression concentration, concentrating the first-stage extract to 5-15% of its original volume; ethanol is recovered during the concentration process; the filtrate includes the filtered liquid and the liquid collected after washing.

[0017] By adopting the above technical solution, the concentration in this application through vacuum decompression can preferably evaporate a large amount of ethanol, and the remaining liquid in the concentrate is basically water. As a result, a large amount of rosmarinic acid, rosmarinic acid and ursolic acid will precipitate out and form filter residue. Rosmarinic acid is water-soluble, so it can be separated from other active components.

[0018] Preferably, in step S3, the extractant is ethyl acetate.

[0019] By adopting the above technical solution, this application uses ethyl acetate for further extraction, which can further remove impurities, improve the purity of rosmarinic acid, and obtain crude rosmarinic acid with higher purity.

[0020] Preferably, in step S4, the mass concentration of ethanol in the mixed solution of ethanol and water with the second-step concentration is 55-65%; the amount of mixed solvent added is 25-30 times the mass of the filter residue; the re-extraction temperature is room temperature; and the re-extraction time is 0.5-1.5 h.

[0021] By adopting the above technical solution, this application can significantly reduce the dissolution of sarsaparilla oleoresin and ursolic acid by controlling the concentration and temperature of ethanol in the extract during re-extraction, so that the solution mainly contains sarsaparilla oleoresin, thereby achieving the separation of sarsaparilla oleoresin and sarsaparilla oleoresin.

[0022] Preferably, in step S5, activated carbon is used as the decolorizing agent.

[0023] By adopting the above technical solution, this application uses activated carbon for decolorization, which can remove colored impurities in the filtrate and improve the quality of oxalic acid.

[0024] Secondly, crude sarsaparilla acid was obtained by the above extraction method.

[0025] The third aspect concerns the application of crude sarsaparilla acid in enhancing the antioxidant effect of vegetable oils.

[0026] Preferably, the crude sarsaparilla acid needs to be pretreated before being added to the vegetable oil, specifically including the following steps:

[0027] Crude caryopsisic acid is dissolved in 90-95% ethanol, followed by the addition of 3-4 times the amount of vegetable oil relative to the caryopsisic acid mass. After stirring and mixing, the mixture is concentrated under vacuum to remove ethanol and water. After cooling, the precipitate is removed by filtration. Finally, fresh vegetable oil is added to adjust the caryopsisic acid mass concentration to 10%, thus obtaining caryopsisic acid oil. Caryopsisic acid oil can be added to vegetable oil as an antioxidant additive to exert an antioxidant effect.

[0028] By adopting the above technical solution, the vegetable oil containing arugula acid in this application is first completely dissolved in high-concentration ethanol, then mixed with a small amount of vegetable oil, and then the ethanol is removed. After that, it is further filtered to remove non-oil-soluble impurities. This method can further improve the arugula acid content, reduce impurities, and ensure the antioxidant properties of the oil. Moreover, mixing it with vegetable oil first avoids the direct addition to vegetable oil, which would cause impurities to precipitate and affect the quality of the oil.

[0029] In summary, this application includes at least one of the following beneficial technical effects:

[0030] 1. This application utilizes the differences in solubility among various active substances in rosemary, and through operations such as extraction, concentration, and re-extraction of filter residue, various active substances can be separated to obtain various crude products. The extraction of oxalic acid will not affect the extraction of other active substances, which can significantly improve the utilization rate of rosemary and thus reduce production costs.

[0031] 2. The crude carrageenan in this application can be directly applied to vegetable oils to play an antioxidant role, which can significantly improve the antioxidant effect of vegetable oils. No further purification is required. Before use, the crude carrageenan can be well blended with vegetable oil and then added to vegetable oils as an additive component. Attached Figure Description

[0032] Figure 1 shows the peroxide value variation curve of sage-containing soybean oil in the application example.

[0033] Figure 2 shows the change in acid value of sarsaparilla acid soybean oil in an application example.

[0034] Figure 3 shows the change in oxalic acid content in soybean oil in an application example.

[0035] Figure 4 shows the changes in soybean oil and food before and after frying in an application example. Detailed Implementation

[0036] Example 1

[0037] S1. Add 25 kg of rosemary leaf powder to 250 kg of 90% ethanol solution and heat to 70°C for the first extraction for 1 hour. After extraction, filter out the filtrate. Add another 250 kg of 90% ethanol solution to the residue and perform a second extraction for 1 hour under the same conditions. After extraction, filter out the filtrate and combine the two filtrates to obtain the extract.

[0038] S2. The extract from step S1 is concentrated under vacuum until it reaches 10% of its original volume to obtain a concentrated solution. The concentrated solution is then subjected to plate and frame filter press. The filter cake is washed with water, and the washing liquid and filtrate are combined to obtain a filtrate. The washed filter cake is the filter residue.

[0039] S3. Extract the filtrate from step S2 with ethyl acetate, concentrate the extract, and dry it under vacuum to obtain crude rosmarinic acid (crude product mass is 1011.14g, purity is 10.21%).

[0040] S4. Add 30 times the equivalent of 60% ethanol solution to the filter residue from step S2 and perform a second extraction at room temperature for 1 hour. After the second extraction is complete, filter to obtain filtrate and filter residue. The filter residue is the crude extract of ursolic acid and caryophyllene (the crude extract has a mass of 1594.49 g, the purity of ursolic acid is 25.33%, and the purity of caryophyllene is 8.67%).

[0041] S5: Decolorize the filtrate from step S4 with activated carbon, then concentrate it into a paste, and then vacuum dry it to obtain crude rat oxalic acid (1510.47g, purity 39.36%).

[0042] Example 2

[0043] S1. Add 25 kg of rosemary leaf powder to 200 kg of 95% ethanol solution and heat to 65°C for the first extraction for 0.5 h. After extraction, filter out the filtrate. Add another 200 kg of 95% ethanol solution to the residue and perform a second extraction for 0.5 h under the same conditions. After extraction, filter out the filtrate and combine the two filtrates to obtain the extract.

[0044] S2. The extract from step S1 is concentrated under vacuum until it reaches 5% of its original volume to obtain a concentrated solution. The concentrated solution is then subjected to plate and frame filter press. The filter cake is washed with water, and the washing liquid and filtrate are combined to obtain a filtrate. The washed filter cake is the filter residue.

[0045] S3. Extract the filtrate from step S2 with ethyl acetate, concentrate the extract, and dry it under vacuum to obtain crude rosmarinic acid (crude product mass is 947.45g, purity is 11.24%).

[0046] S4. Add 25 times the equivalent of 55% ethanol solution to the filter residue from step S2 and perform a second extraction at room temperature for 1.5 hours. After the second extraction is complete, filter to obtain filtrate and filter residue. The filter residue is the crude extract of ursolic acid and caryophyllene (the crude extract has a mass of 1987.67 g, the purity of ursolic acid is 20.54%, and the purity of caryophyllene is 9.17%).

[0047] S5: Decolorize the filtrate from step S4 with activated carbon, then concentrate it into a paste, and vacuum dry it to obtain crude rat oxalic acid (1214.94g, purity 33.85%).

[0048] Example 3

[0049] S1. Add 25 kg of rosemary leaf powder to 200 kg of 85% ethanol solution and heat to 75°C for the first extraction for 1.5 h. After extraction, filter out the filtrate. Add another 200 kg of 85% ethanol solution to the residue and perform a second extraction for 1.5 h under the same conditions. After extraction, filter out the filtrate and combine the two filtrates to obtain the extract.

[0050] S2. The extract from step S1 is concentrated under vacuum to 15% of its original volume to obtain a concentrated solution. The concentrated solution is then subjected to plate and frame filter press. The filter cake is washed with water, and the washing liquid and filtrate are combined to obtain a filtrate. The washed filter cake is the filter residue.

[0051] S3. Extract the filtrate from step S2 with ethyl acetate, concentrate the extract, and dry it under vacuum to obtain crude rosmarinic acid (crude product mass is 1429.64g, purity is 8.57%).

[0052] S4. Add 35 times the equivalent of 65% ethanol solution to the filter residue from step S2 and perform a second extraction at room temperature for 0.5 hours. After the second extraction is complete, filter to obtain filtrate and filter residue. The filter residue is the crude extract of ursolic acid and caryophyllene (the crude extract has a mass of 1315.32 g, the purity of ursolic acid is 31.14%, and the purity of caryophyllene is 7.94%).

[0053] S5: Decolorize the filtrate from step S4 with activated carbon, then concentrate it into a paste, and then vacuum dry it to obtain crude rat oxalic acid (1650.55g, purity 36.37%).

[0054] Application Example 1

[0055] The crude carotenoid acid from Example 1 was dissolved in 95% ethanol. Then, 3.5 times the mass of vegetable oil relative to carotenoid acid was added. After stirring and mixing, the mixture was concentrated under vacuum to remove ethanol and water. After cooling, the precipitate was removed by filtration. Finally, fresh vegetable oil was added to adjust the mass concentration of carotenoid acid to 10%, thus obtaining carotenoid acid oil.

[0056] Antioxidant test:

[0057] (1) Prepare three frying pans, labeled A, B and C respectively. Add 1 kg of soybean oil without added oxalic acid to pan A as a blank control group. Add 1 kg of soybean oil with oxalic acid at final concentrations of 0.05% and 0.1% to pans B and C respectively as treatment groups.

[0058] (2) Take a small amount of oil samples from pots A, B and C respectively for peroxide value, acid value and sage acid content HPLC detection, and record the results as 0d as the initial control.

[0059] (3) Add the same weight of fried meat products to A, B and C respectively, fry at the same temperature (160℃) for 20 minutes, remove the food, continue heating for 6 hours, take a small amount of frying oil for peroxide value, acid value and oxalic acid content HPLC detection, and record it as 1 day of frying.

[0060] The peroxide value and acid value of the edible oils were tested using corresponding rapid test strips, both of which were purchased from Guangdong Dayuan Oasis Food Safety Technology Co., Ltd.

[0061] (4) The subsequent frying and testing steps are the same as (3), and are recorded in order as frying on days 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11.

[0062] (5) Record the frying time and various test indicators in detail every day.

[0063] 1. The antioxidant effect of crude sarsaparilla acid on soybean oil is shown in Table 1 and Figure 1.

[0064] Table 1. Determination of peroxide value in soybean oil containing sage

[0065]

[0066] As shown in Figure 1, the amount of oxalic acid added at different specifications had a significant impact on the antioxidant properties of soybean oil. In the early frying process, the antioxidant properties of soybean oil did not change with the extension of frying time. However, starting from the fourth day, soybean oil without added oxalic acid and soybean oil containing 0.05% oxalic acid began to show significant changes, and the peroxide value increased rapidly after the seventh day. Soybean oil containing 0.1% oxalic acid showed stable antioxidant properties, indicating that soybean oil with this specification of oxalic acid has a significant effect on antioxidant properties.

[0067] 2. The effect of oxalic acid on the acid value of soybean oil. The test results are shown in Table 2 and Figure 2.

[0068] Table 2. Determination of Acid Value of Soybean Oil with Sageretia prostrata

[0069]

[0070] As shown in Table 2 and Figure 2, the initial acid value of soybean oil with added carrageenan was higher than that of the control group. With the extension of frying time, the acid value of the control group increased significantly, reaching the national health standard limit on the 5th day of continuous frying. The acid value growth rate of group B containing 0.05% carrageenan slowed down, reaching the limit on the 11th day of continuous frying, while group C containing 0.1% carrageenan showed stable performance. This indicates that soybean oil with 0.1% carrageenan has a significant effect on prolonging the quality change of frying oil.

[0071] 3. The changes in oxalic acid content during soybean oil frying are shown in Table 3 and Figure 3.

[0072] Table 3. Determination of oxalic acid content in soybean oil (HPLC)

[0073]

[0074] As shown in Table 3 and Figure 3, the content of oxalic acid in soybean oil gradually decreases with the extension of frying time, indicating that the oxidative deterioration of soybean oil during food frying is related to the change in oxalic acid content, and that oxalic acid can slow down the deterioration rate of frying oil.

[0075] 4. Effects of oxalic acid antioxidant on sensory evaluation during soybean oil frying

[0076] For consumers, the most direct source of judgment on food quality is sensory perception. Quality is generally a subjective judgment, which may be influenced by individual differences in perception. During frying, soybean oil undergoes complex chemical reactions, gradually accumulating a series of deteriorating products. These adversely affect the oil's sensory qualities and overall quality, particularly its color and viscosity. As shown in Figure 4, with prolonged frying time, the control group's soybean oil showed significant color changes before and after frying, and its viscosity and light transmittance also decreased significantly. Compared to the blank control group, at the same frying time, the oil in the antioxidant-added group had a lighter color and lower viscosity than the control group. Furthermore, the soybean oil with 0.1% oxalic acid was in even better condition, indicating that adding oxalic acid effectively inhibits the increase in oil viscosity and delays color deterioration during frying. This may be related to the fact that the added antioxidant inhibits the formation of carbonyl compounds in the oil.

[0077] In terms of overall antioxidant effect, this study investigated the influence of oxalic acid (XAR) antioxidant on the quality of soybean oil under high-temperature frying conditions. The practical application effect of XAR antioxidant was evaluated by measuring the acid value, peroxide value, color, and viscosity of the oil. The results showed that, compared with the control group, the addition of XAR effectively inhibited the increase in acid value of the frying oil, while also effectively maintaining the viscosity and sensory quality of the oil. During the first 3 days of frying, the peroxide value of both the control and experimental groups remained essentially unchanged. From 3 to 11 days, the upward trend in the XAR antioxidant of the experimental group slowed down. Specifically, the peroxide value of soybean oil with 0.1% XAR antioxidant remained essentially unchanged, while the peroxide value of the control group continued to increase. This indicates that XAR antioxidant has a significant inhibitory effect on the decline in the physicochemical quality of frying oil, and the optimal addition level is 0.1% (HPLC). Meanwhile, sarsaparilla acid can inhibit the degradation of unsaturated fatty acids in frying oil, which may be related to the inhibition of the production of volatile aldehydes in the oil, maintaining the frying performance of the oil, increasing the oxidative stability of the oil, and thus protecting the quality of the oil during the frying process.

[0078] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A process for extracting oxalic acid from rat's tail, characterized in that, Includes the following steps: S1. Rosemary leaves are added to a mixed solution of ethanol and water of the first-order concentration and heated for extraction. After extraction, the first-order extract is obtained. S2. The first-order extract from step S1 is concentrated, and the concentrate is filtered by plate and frame pressing. The filter cake is washed with water to obtain filtrate and residue. S3. The filtrate from step S2 is extracted, and the extract is concentrated and dried to obtain crude rosmarinic acid. S4. The residue from step S2 is re-extracted using a mixed solution of ethanol and water of the second-order concentration at room temperature. After re-extraction, it is filtered to obtain filtrate and residue. The residue is the crude extract of ursolic acid and caryophyllene. S5. The filtrate from step S4 is decolorized... After being concentrated into a paste and vacuum dried, crude oxalic acid is obtained. In step S1, the mass concentration of ethanol in the first-stage concentration mixed solution of ethanol and water is 85-95%, the extraction is performed 2-3 times, the extraction time is 0.5-1.5 h, the extraction temperature is 65-75℃, and 8-12 times the mass of the mixed solution relative to the rosemary mass is added for each extraction. In step S4, the mass concentration of ethanol in the second-stage concentration mixed solution of ethanol and water is 55-65%, the amount of mixed solvent added is 25-30 times the mass of the filter residue, the re-extraction temperature is room temperature, and the re-extraction time is 0.5-1.5 h. In step S3, the extractant is ethyl acetate.

2. The process for extracting oxalic acid according to claim 1, characterized in that, In step S2, the concentration is carried out by vacuum decompression concentration, which concentrates the first-stage extract to 5-15% of its original volume; ethanol is recovered during the concentration process.

3. The process for extracting oxalic acid according to claim 1, characterized in that, In step S5, activated carbon is used as the decolorizing agent.

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