Fresh-keeping preservative for sauced products and preparation method of fresh-keeping preservative

Abstract

The invention discloses a fresh-keeping preservative for sauced products and a preparation method of the fresh-keeping preservative, and belongs to the technical field of preservatives. The preservative prepared by the invention is prepared from modified catechin, Arabic gum, vitamin E, sodium citrate, citric acid and deionized water according to the mass ratio of (15 to 20): (4 to 8): (0.5 to 1.5): (1.5 to 3): (0.05 to 0.1): (70 to 75). During preparation, catechin is esterified through organic acid to obtain modified catechin, then Arabic gum is dissolved in deionized water to prepare a colloidal solution, the modified catechin, vitamin E and sodium citrate are sequentially added into the colloidal solution, stirring conditions are controlled, and finally the fresh-keeping preservative is obtained. The liposolubility and stability of catechin are improved through esterification modification, the dispersibility is enhanced in cooperation with Arabic gum, efficient preservation and corrosion prevention are achieved, and the edible safety and quality of sauced and marinated products are guaranteed.

Description

Technical Field

[0001] This application belongs to the field of preservative technology, specifically relating to a preservative for braised and marinated products and its preparation method. Background Technology

[0002] Braised and stewed products, as an important category of traditional meat processing in my country, are favored by consumers for their unique flavor, rich nutrition, and convenient consumption, occupying an important position in the food market. These products are typically made from livestock and poultry meat, soy products, etc., processed through braising and stewing techniques. This processing introduces a large amount of protein, fat, carbohydrates, and other nutrients. Simultaneously, the high moisture content and suitable pH environment provide favorable conditions for microbial growth and reproduction. During the production, transportation, and sales of braised and stewed products, microbial contamination and fat oxidation are the main causes of quality deterioration and shortened shelf life. Once spoiled, products not only exhibit off-odors, changes in color, and deterioration in texture, but may also produce harmful substances, posing a threat to consumer health and causing economic losses to production enterprises. Therefore, developing safe and efficient preservation and anti-corrosion technologies to extend the shelf life of braised and stewed products and ensure their food safety and quality stability has become a critical issue that the braised and stewed product industry urgently needs to address. Currently, commonly used preservation and anti-corrosion methods fall into two main categories: physical preservation and chemical preservation. Among chemical preservation methods, chemical preservatives are the most frequently used, offering advantages such as low cost and good efficacy. However, chemical preservatives have poor natural degradation capabilities and may accumulate in the human body, potentially causing harm. Therefore, natural preservatives have emerged. Existing natural preservatives are mainly extracted from various natural plants, offering advantages such as high safety, good compatibility, and minimal impact on the flavor of the product, making them a research hotspot in recent years. Chinese invention patent CN111838296A discloses a natural preservative for braised meat products, comprising the following ingredients in parts by weight: 0.1-0.5 parts grape seed extract, 0.1-0.5 parts nutmeg extract, 0.1-0.5 parts clove extract, 0.2-1.2 parts tea polyphenols, 0.8-2.4 parts pomegranate peel extract, and 0.6-3.2 parts dehydrated vinegar powder. This preservative is mainly made from natural plants and fermentation products. It has a broad antibacterial range, good preservation effect, and the advantages of removing fishy smell and enhancing flavor. It can significantly improve the overall flavor of meat products and significantly extend the shelf life of food.

[0003] However, among existing natural preservatives, such as catechins, the dispersibility in mixed systems of water and oil phases, such as soy sauce and braising liquid, is not as good as that of chemical preservatives, and they are easily oxidized and become ineffective. Therefore, developing a highly efficient and stable natural preservative has become an urgent problem to be solved. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the primary objective of this application is to provide a preservative for braised and marinated products and its preparation method, so as to solve the problems of poor dispersibility and stability of existing natural preservatives.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] In a first aspect, this application provides a preservative for braised and marinated products, comprising: modified catechin, gum arabic, vitamin E, sodium citrate, citric acid, and deionized water; wherein the modified catechin is obtained by esterification reaction of natural organic acids and catechin.

[0007] Furthermore, the mass ratio of the modified catechin, gum arabic, vitamin E, sodium citrate, citric acid and deionized water is (15~20):(4~8):(0.5~1.5):(1.5~3):(0.05~0.1):(70~75).

[0008] Furthermore, the natural organic acid includes any one of citric acid, malic acid, rosmarinic acid, and tartaric acid.

[0009] It should be noted that catechins, as active ingredients extracted from natural plants such as green tea, possess excellent antibacterial properties. However, natural catechins suffer from poor stability, are easily oxidized and decomposed, and have poor solubility and dispersibility in aqueous systems. Organic acids can enhance the solubility of catechins in oils through esterification reactions between the carboxyl groups and the phenolic hydroxyl groups in catechins, thereby improving their dispersibility in mixed systems. This makes it less likely for preservatives to agglomerate in the braising liquid, allowing them to disperse more easily on the surface of food and increasing the efficiency of contact between preservatives and bacteria. At the same time, esterified catechins have higher stability and can maintain their activity for a longer period of time. In addition, the addition of gum arabic further improves the dispersibility of modified catechins and other preservatives in the braising liquid, ensuring uniform dispersion of active ingredients and enhancing the preservation and anti-corrosion effect.

[0010] Secondly, this application provides a method for preparing a preservative for braised and marinated products, comprising the following steps:

[0011] Modified catechins were obtained by modifying catechins with natural organic acids.

[0012] A colloidal solution of arabic was prepared by adding gum arabic to deionized water.

[0013] It should be noted that gum arabic has good emulsifying, stabilizing, and dispersing properties. This step ensures that gum arabic is uniformly dispersed in deionized water, providing a basis for the dispersion of modified catechins.

[0014] Modified catechin and vitamin E were added sequentially to an arabic colloid solution to obtain a compound solution;

[0015] It should be noted that vitamin E is a natural antioxidant. When combined with preservatives, it works synergistically with modified catechins. On the one hand, it can scavenge free radicals and enhance the antioxidant capacity of food. On the other hand, it can also prevent modified catechins from being oxidized and deactivated, thus extending the shelf life of the preservative.

[0016] Sodium citrate and citric acid are added to the compound solution and stirred evenly to obtain a preservative.

[0017] It should be noted that sodium citrate and citric acid mainly act as buffers, playing a role in assisting preservation and maintaining system stability. Metal ions in braised and marinated products can catalyze oil oxidation and microbial growth. Sodium citrate can reduce the activity of metal ions by forming chelates with them, thus helping to extend the shelf life. At the same time, sodium citrate and trace amounts of citric acid can stabilize the pH of the preservative between 5.5 and 7, preventing the modified catechins from hydrolyzing due to excessively high pH or the flavor of the ingredients from being affected by excessively low pH.

[0018] Furthermore, the specific steps of the modification treatment are as follows:

[0019] Add catechin to anhydrous ethanol and stir at 700-900 rpm for 10-15 min to obtain a catechin ethanol solution.

[0020] The natural organic acid was added to the catechin ethanol solution in three portions, with a 3-minute interval between each addition, and the mixture was stirred for 5-10 minutes to obtain mixture A.

[0021] It should be noted that catechins contain multiple phenolic hydroxyl groups, which have an inactivating effect on microorganisms. The esterification reaction between organic acids and catechins will consume some of the phenolic hydroxyl groups. Therefore, it is necessary to control the amount of organic acids added and add them in batches to avoid multiple phenolic hydroxyl groups reacting, thereby reducing the overall activity of the preservative.

[0022] Transfer the mixture A into a reflux apparatus. Add the catalyst dropwise to the mixture at a temperature of 60-65℃ and a stirring rate of 1000-1200 rpm. Perform constant temperature reflux for 2-3 hours. Then cool to room temperature, add deionized water, and stir for 5-10 minutes to obtain mixture B.

[0023] Transfer the mixture B into a separatory apparatus, let it stand for 10-20 minutes to remove the lower aqueous phase, and obtain the organic phase; add saturated sodium bicarbonate solution to the organic phase, then let it stand for 10-20 minutes to remove the lower aqueous phase, and obtain the purified organic phase;

[0024] The purified organic phase was transferred into an evaporation apparatus and subjected to vacuum distillation at a vacuum of 0.08~0.09MPa and 50~55℃ to obtain crude modified catechins. The crude modified catechins were then dissolved, chromatographically analyzed, and distilled to obtain modified catechins.

[0025] It should be noted that catalysts and organic acid impurities in the mixture can be removed by separation and the addition of saturated sodium bicarbonate, and ethanol solvent can be removed by vacuum distillation.

[0026] Furthermore, the mass ratio of the catechin, anhydrous ethanol, natural organic acid, catalyst, deionized water and saturated sodium bicarbonate solution is (15~23):(38~45):(10.5~14):(0.15~0.25):(14~17):(6~9).

[0027] Furthermore, the catalyst is food-grade concentrated sulfuric acid.

[0028] Furthermore, the specific steps for preparing the arabic colloidal solution are as follows:

[0029] Add deionized water to the reactor and turn on the heating and stirring at a temperature of 50-60℃ and a stirring speed of 500-600 rpm. Then add gum arabic to the deionized water and stir at a constant temperature for 20-30 minutes. Then keep it warm and let it stand for 5-10 minutes to obtain a gum arabic solution.

[0030] Furthermore, the specific preparation steps of the compound solution are as follows:

[0031] Add the modified catechin to the arabic colloid solution and increase the stirring speed to 800-1000 rpm. After the modified catechin is added, continue to add vitamin E to the arabic colloid solution and continue stirring for 15-20 minutes to obtain the compound solution.

[0032] Furthermore, the specific steps for adding the modified catechin to the arabic colloid solution are as follows: the modified catechin is added to the arabic colloid solution in 4 to 8 portions, with an interval of 2 minutes between each addition.

[0033] It should be noted that the modified catechin is an amphiphilic molecule, while the arabic colloid solution is an aqueous phase. The two have a certain tendency to separate into phases. The modified catechin is added in batches to avoid adding too much fat-soluble component at once, which would exceed the emulsification carrying capacity of the colloid and cause stratification or aggregation.

[0034] The beneficial effects of this application are:

[0035] This application modifies catechins using natural organic acids. The carboxyl groups carried by the natural organic acids react with the phenolic hydroxyl groups in the catechins to obtain esterified catechins. By controlling the amount of organic acid and reaction conditions, the lipophilicity of the catechins is improved without significantly reducing their antibacterial effect. This allows for more uniform dispersion in a sauce-water-oil mixture system, improving the contact efficiency between the preservative and bacteria / microorganisms, thus enhancing the preservative effect. Simultaneously, the esterified catechins, with their ester groups, exhibit better stability than the phenolic hydroxyl groups, reducing the risk of oxidative inactivation. Furthermore, by adding sodium citrate and a trace amount of citric acid to the preservative system, the pH of the system is maintained in the neutral to slightly acidic range, preventing the hydrolysis and inactivation of the phenolic hydroxyl groups on the modified catechins in acidic or alkaline environments. Sodium citrate and citric acid also act as antibacterial substances, further enhancing the preservative and antibacterial effects. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 A flowchart illustrating the preparation method of a preservative for braised and marinated products provided in this application. Detailed Implementation

[0038] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0039] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0040] The following specific embodiments further illustrate this point:

[0041] Example 1

[0042] A method for preparing a preservative for braised and marinated products:

[0043] 1. Add catechin to anhydrous ethanol and stir at 700 rpm for 10 min to obtain a catechin ethanol solution; then add citric acid to the catechin ethanol solution in three portions, with an interval of 3 min between each portion, and stir for 5 min each time to obtain mixture A;

[0044] 2. Transfer mixture A into a reflux apparatus. At a temperature of 60°C and a stirring speed of 1000 rpm, add food-grade concentrated sulfuric acid dropwise to mixture A and reflux at a constant temperature for 2 hours. Then cool to room temperature, add deionized water, and stir for 5 minutes to obtain mixture B.

[0045] 3. Transfer mixture B into a separatory apparatus, let stand for 10 min, remove the lower aqueous phase to obtain the organic phase; add saturated sodium bicarbonate solution to the organic phase, then let stand for 10 min, remove the lower aqueous phase to obtain the purified organic phase; transfer the purified organic phase into an evaporator, and perform vacuum distillation at 0.08 MPa and 50℃ to obtain crude modified catechin; dissolve the crude modified catechin, perform chromatography, and distillation to obtain modified catechin for later use;

[0046] 4. Add deionized water to the reaction vessel and turn on the heating and stirring at 50°C and 500 rpm. Then add gum arabic to the deionized water, stir at a constant temperature for 20 minutes, and then keep it at the temperature and let it stand for 5 minutes to obtain a gum arabic solution.

[0047] 5. Add the modified catechin to the arabic colloid solution in 4 portions, with an interval of 2 minutes between each addition, and increase the stirring speed to 800 rpm. After the modified catechin is added, continue to add vitamin E to the arabic colloid solution and continue stirring for 15 minutes to obtain the compound solution.

[0048] 6. Add sodium citrate and citric acid to the compound solution, reduce the stirring speed to 500 rpm, and stir for 5 minutes to obtain the preservative described in Example 1.

[0049] In this embodiment, the mass ratio of catechin, anhydrous ethanol, citric acid, food-grade concentrated sulfuric acid, deionized water, and saturated sodium bicarbonate solution in steps 1, 2, and 3 is 15:45:14:0.15:17:8.85.

[0050] The mass ratio of deionized water, gum arabic, modified catechin, vitamin E, sodium citrate, and citric acid in steps 4, 5, and 6 is 70:5.95:20:1:3:0.05.

[0051] Example 2

[0052] A method for preparing a preservative for braised and marinated products:

[0053] 1. Add catechin to anhydrous ethanol and stir at 800 rpm for 12 min to obtain a catechin ethanol solution; then add DL-malic acid to the catechin ethanol solution in three portions, with an interval of 3 min between each portion, and stir for 8 min to obtain mixture A;

[0054] 2. Transfer mixture A into a reflux apparatus. At a temperature of 62°C and a stirring speed of 1100 rpm, add food-grade concentrated sulfuric acid dropwise to mixture A and reflux at a constant temperature for 2.5 hours. Then cool to room temperature, add deionized water, and stir for 8 minutes to obtain mixture B.

[0055] 3. Transfer mixture B into a separatory apparatus, let stand for 15 min, remove the lower aqueous phase to obtain the organic phase; add saturated sodium bicarbonate solution to the organic phase, then let stand for 15 min, remove the lower aqueous phase to obtain the purified organic phase; transfer the purified organic phase into an evaporator, and perform vacuum distillation at 0.085 MPa and 52℃ to obtain crude modified catechin; dissolve the crude modified catechin, perform chromatography, and distillation to obtain modified catechin for later use;

[0056] 4. Add deionized water to the reaction vessel and turn on the heating and stirring at 55°C and 550 rpm. Then add gum arabic to the deionized water, stir at a constant temperature for 25 minutes, and then keep it at the temperature and let it stand for 8 minutes to obtain a gum arabic solution.

[0057] 5. Add the modified catechin to the arabic colloid solution in 6 portions, with an interval of 2 minutes between each addition, and increase the stirring speed to 900 rpm. After the modified catechin is added, continue to add vitamin E to the arabic colloid solution and continue stirring for 18 minutes to obtain the compound solution.

[0058] 6. Add sodium citrate and citric acid to the compound solution, reduce the stirring speed to 550 rpm, and stir for 8 minutes to obtain the preservative described in Example 2.

[0059] In this embodiment, the mass ratio of catechin, anhydrous ethanol, DL-malic acid, food-grade concentrated sulfuric acid, deionized water, and saturated sodium bicarbonate solution in steps 1, 2, and 3 is 20.3:43:10.5:0.2:17:9.

[0060] The mass ratio of deionized water, gum arabic, modified catechin, vitamin E, sodium citrate, and citric acid in steps 4, 5, and 6 is 75:7.9:15:0.5:1.5:0.1.

[0061] Example 3

[0062] A method for preparing a preservative for braised and marinated products:

[0063] 1. Add catechin to anhydrous ethanol and stir at 900 rpm for 15 min to obtain a catechin ethanol solution; then add rosmarinic acid to the catechin ethanol solution in three portions, with an interval of 3 min between each portion, and stir for 10 min to obtain mixture A;

[0064] 2. Transfer mixture A into a reflux apparatus. At a temperature of 65°C and a stirring speed of 1200 rpm, add food-grade concentrated sulfuric acid dropwise to mixture A and reflux at a constant temperature for 3 hours. Then cool to room temperature, add deionized water, and stir for 10 minutes to obtain mixture B.

[0065] 3. Transfer mixture B into a separatory apparatus, let stand for 20 min, remove the lower aqueous phase to obtain the organic phase; add saturated sodium bicarbonate solution to the organic phase, then let stand for 20 min, remove the lower aqueous phase to obtain the purified organic phase; transfer the purified organic phase into an evaporator, and perform vacuum distillation at 0.09 MPa and 55℃ to obtain crude modified catechin; dissolve the crude modified catechin, perform chromatography, and distillation to obtain modified catechin for later use;

[0066] 4. Add deionized water to the reaction vessel and turn on the heating and stirring at 60°C and 600 rpm. Then add gum arabic to the deionized water, stir at a constant temperature for 30 minutes, and then keep it at the temperature and let it stand for 10 minutes to obtain a gum arabic solution.

[0067] 5. Add the modified catechin to the arabic colloid solution in 8 portions, with an interval of 2 minutes between each addition, and increase the stirring speed to 1000 rpm. After the modified catechin is added, continue to add vitamin E to the arabic colloid solution and continue stirring for 20 minutes to obtain the compound solution.

[0068] 6. Add sodium citrate and citric acid to the compound solution, reduce the stirring speed to 600 rpm, and stir for 10 min to obtain the preservative described in Example 3.

[0069] In this embodiment, the mass ratio of catechin, anhydrous ethanol, rosmarinic acid, food-grade concentrated sulfuric acid, deionized water, and saturated sodium bicarbonate solution in steps 1, 2, and 3 is 23:38:13.75:0.25:16:9.

[0070] The mass ratio of deionized water, gum arabic, modified catechin, vitamin E, sodium citrate, and citric acid in steps 4, 5, and 6 is 74:4:18.42:1.5:2:0.08.

[0071] Example 4

[0072] A method for preparing a preservative for braised and marinated products:

[0073] 1. Add catechin to anhydrous ethanol and stir at 700 rpm for 10 min to obtain a catechin ethanol solution; then add tartaric acid to the catechin ethanol solution in three portions, with an interval of 3 min between each portion, and stir for 5 min each time to obtain mixture A;

[0074] 2. Transfer mixture A into a reflux apparatus. At a temperature of 60°C and a stirring speed of 1000 rpm, add food-grade concentrated sulfuric acid dropwise to mixture A and reflux at a constant temperature for 2 hours. Then cool to room temperature, add deionized water, and stir for 5 minutes to obtain mixture B.

[0075] 3. Transfer mixture B into a separatory apparatus, let stand for 10 min, remove the lower aqueous phase to obtain the organic phase; add saturated sodium bicarbonate solution to the organic phase, then let stand for 10 min, remove the lower aqueous phase to obtain the purified organic phase; transfer the purified organic phase into an evaporator, and perform vacuum distillation at 0.08 MPa and 50℃ to obtain crude modified catechin; dissolve the crude modified catechin, perform chromatography, and distillation to obtain modified catechin for later use;

[0076] 4. Add deionized water to the reaction vessel and turn on the heating and stirring at 50°C and 500 rpm. Then add gum arabic to the deionized water, stir at a constant temperature for 20 minutes, and then keep it at the temperature and let it stand for 5 minutes to obtain a gum arabic solution.

[0077] 5. Add the modified catechin to the arabic colloid solution in 4 portions, with an interval of 2 minutes between each addition, and increase the stirring speed to 800 rpm. After the modified catechin is added, add 1 part of vitamin E to the arabic colloid solution and continue stirring for 15 minutes to obtain the compound solution.

[0078] 6. Add sodium citrate and citric acid to the compound solution, reduce the stirring speed to 500 rpm, and stir for 5 minutes to obtain the preservative described in Example 4.

[0079] In this embodiment, the mass ratio of catechin, anhydrous ethanol, rosmarinic acid, food-grade concentrated sulfuric acid, deionized water, and saturated sodium bicarbonate solution in steps 1, 2, and 3 is 20:45:14.85:0.15:14:6.

[0080] The mass ratio of deionized water, gum arabic, modified catechin, vitamin E, sodium citrate, and citric acid in steps 4, 5, and 6 is 70:8:17.95:1:3:0.05.

[0081] Comparative Example 1

[0082] The difference between Comparative Example 1 and Example 1 is that the catechins were not esterified. The remaining steps are the same as in Example 1 and will not be repeated here.

[0083] Comparative Example 2

[0084] The difference between Comparative Example 2 and Example 1 is that gum arabic was not added when compounding the preservatives. The remaining steps are the same as in Example 1 and will not be repeated here.

[0085] Comparative Example 3

[0086] The difference between Comparative Example 3 and Example 1 is that citric acid was added all at once during the modification of catechins, instead of in batches. The remaining steps are the same as in Example 1 and will not be repeated here.

[0087] To demonstrate the preservation effect of the preservative provided in this application on ingredients such as braised duck parts, the colony count method was used to test the number of colonies of braised duck wings treated in Examples 1-4 and Comparative Examples 1-3 after natural storage for 7 days. The preservation effect of the preservative was evaluated by the number of colonies.

[0088] The braised duck wings were divided into different experimental groups and control groups. Examples 1-4 and Comparative Examples 1-3 were added to the braised duck wings of the experimental groups at a concentration of 0.1%. The mixture was then slowly stirred for 5 minutes. The braised duck wings of each experimental group and the control group were placed in the same experimental environment and left for 7 days. The number of bacterial colonies on the braised duck wings of each experimental group and the control group was then detected. The test results are shown in Table 1.

[0089] Table 1. Colony count test results of Examples 1-5 and Comparative Examples 1-3

[0090]

[0091] As shown in Table 1 above, the bacterial count of braised duck wings treated with preservatives prepared in Examples 1-4 was significantly lower than that in Comparative Examples 1-3. This is mainly because, in the preparation process, Comparative Example 1 did not modify the catechins by esterification. This resulted in less uniform dispersion of the preservatives when mixed in the braising liquid compared to esterified catechins, leading to uneven distribution of the preservatives on the braised duck wings. In areas with less preservative, bacteria were more likely to grow. Furthermore, unmodified catechins are more easily oxidized and deactivated, resulting in a shorter shelf life. In Comparative Example 2, the lack of gum arabic for more thorough dispersion of the preservatives resulted in a weaker antibacterial effect compared to the preservatives in the examples. In Comparative Example 3, citric acid was added all at once during the preparation process, leading to an increase in the number of substituted phenolic hydroxyl groups on the catechins, thus weakening the antibacterial effect of the catechins. Therefore, the comparative experiments show that the preservative prepared in the embodiments of this application has good antibacterial and preservative effects, is natural and harmless, has a long shelf life, and is suitable for the preservation and preservation of braised products.

[0092] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application, and all such modifications and substitutions should be covered within the scope of the claims of this application.

Claims

1. A preservative for braised and marinated products, characterized in that, The components include: modified catechins, gum arabic, vitamin E, sodium citrate, citric acid, and deionized water; the modified catechins are obtained by esterification reaction of natural organic acids and catechins.

2. The preservative for braised and marinated products according to claim 1, characterized in that, The mass ratio of the modified catechin, gum arabic, vitamin E, sodium citrate, citric acid and deionized water is (15~20):(4~8):(0.5~1.5):(1.5~3):(0.05~0.1):(70~75).

3. The preservative for braised and marinated products according to claim 1, characterized in that, The natural organic acids include any one of citric acid, malic acid, rosmarinic acid, and tartaric acid.

4. A method for preparing a preservative for braised and marinated products, characterized in that, Includes the following steps: Modified catechins were obtained by modifying catechins with natural organic acids. A colloidal solution of arabic was prepared by adding gum arabic to deionized water. Modified catechin and vitamin E were added sequentially to an arabic colloid solution to obtain a compound solution; Sodium citrate and citric acid are added to the compound solution and stirred evenly to obtain a preservative.

5. The method for preparing a preservative for braised products according to claim 4, characterized in that, The specific steps of the modification process are as follows: Add catechins to anhydrous ethanol and stir at 700-900 rpm for 10-15 min to obtain a catechin ethanol solution. The natural organic acid was added to the catechin ethanol solution in three portions, with a 3-minute interval between each addition, and the mixture was stirred for 5-10 minutes to obtain mixture A. The mixture A was transferred into a reflux apparatus. At a temperature of 60-65℃ and a stirring speed of 1000-1200 rpm, a catalyst was added dropwise to the mixture A. The mixture was then refluxed at a constant temperature for 2-3 hours. After cooling to room temperature, deionized water was added and the mixture was stirred for 5-10 minutes to obtain mixture B. Transfer the mixture B into a separatory apparatus, let it stand for 10-20 minutes to remove the lower aqueous phase, and obtain the organic phase; add saturated sodium bicarbonate solution to the organic phase, then let it stand for 10-20 minutes to remove the lower aqueous phase, and obtain the purified organic phase; The purified organic phase was transferred into an evaporation apparatus and subjected to vacuum distillation at a vacuum of 0.08~0.09MPa and 50~55℃ to obtain crude modified catechins. The crude modified catechins were then dissolved, chromatographically analyzed, and distilled to obtain modified catechins.

6. The method for preparing a preservative for braised products according to claim 5, characterized in that, The mass ratio of the catechin, anhydrous ethanol, natural organic acid, catalyst, deionized water and saturated sodium bicarbonate solution is (15~23):(38~45):(10.5~14):(0.15~0.25):(14~17):(6~9).

7. A method for preparing a preservative for braised products according to claim 5, characterized in that, The catalyst is food-grade concentrated sulfuric acid.

8. A method for preparing a preservative for braised and marinated products according to claim 4, characterized in that, The specific steps for preparing the arabic colloidal solution are as follows: Add deionized water to the reactor and turn on the heating and stirring at a temperature of 50-60℃ and a stirring speed of 500-600 rpm. Then add gum arabic to the deionized water and stir at a constant temperature for 20-30 minutes. Then keep it warm and let it stand for 5-10 minutes to obtain a gum arabic solution.

9. A method for preparing a preservative for braised and marinated products according to claim 4, characterized in that, The specific preparation steps of the compound solution are as follows: Add the modified catechin to the arabic colloid solution and increase the stirring speed to 800-1000 rpm. After the modified catechin is added, continue to add vitamin E to the arabic colloid solution and continue stirring for 15-20 minutes to obtain the compound solution.

10. A method for preparing a preservative for braised products according to claim 9, characterized in that, The specific steps for adding modified catechins to the arabic colloid solution are as follows: the modified catechins are added to the arabic colloid solution in 4 to 8 portions, with an interval of 2 minutes between each addition.

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