Agricultural product preservative based on traditional Chinese medicinal material source carbon dots and preparation method and application thereof

Abstract

The application discloses to the technical field of agricultural product preservative, and particularly discloses an agricultural product preservative based on traditional Chinese medicinal material source carbon dots and a preparation method and application thereof, which comprises traditional Chinese medicinal material source carbon dots and a solvent, wherein the traditional Chinese medicinal material source carbon dots are one of Astragalus membranaceus, licorice, honeysuckle, Coptis chinensis and angelica; the concentration of the traditional Chinese medicinal material source carbon dots in the preservative is 0.1-1.0 mg / mL; and the solvent is deionized water. According to the application, the traditional Chinese medicinal material is selected as the only carbon source, and the hydrothermal synthesis and purification process are optimized, so that the carbon dot preparation process is green and environmentally friendly, the carbon dot preparation cost is reduced, the carbon dot purity and safety are improved, and the cytotoxicity caused by the photo-degradation of the carbon dots is avoided.

Description

Technical Field

[0001] This invention relates to the field of agricultural product preservatives, specifically to an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials, its preparation method, and its application. Background Technology

[0002] Postharvest preservation of agricultural products is a crucial link in the agricultural industry chain, directly affecting the commodity value, market circulation efficiency, and economic benefits of agricultural products. Traditional methods of preserving agricultural products are mainly divided into two categories: one is physical methods such as low-temperature storage and controlled atmosphere storage, and the other is chemical methods that involve adding chemical preservatives.

[0003] Carbon dots, as a novel zero-dimensional carbon nanomaterial, possess advantages such as small particle size (typically less than 10 nm), excellent fluorescence properties, low toxicity, good biocompatibility, and relatively low preparation cost. In recent years, they have been widely researched and applied in fields such as biomedicine, sensing and detection, and environmental remediation. With the deepening of carbon dot research, its application potential in the field of agricultural product preservation is gradually being explored. However, related research is still in its early stages, and mature and systematic application solutions have not yet been formed.

[0004] In existing technologies, carbon dots are mostly prepared using chemical reagents (such as citric acid, glucose, urea, etc.) or industrial byproducts (such as coal tar, waste plastics, etc.) as carbon sources. Although carbon dots can be synthesized, there are obvious limitations: for example, existing carbon dot preparation technologies suffer from environmentally unfriendly carbon sources, high costs, or insufficient safety. Using citric acid as a carbon source results in high raw material costs (citric acid market price is about 8-10 yuan / kg), and auxiliary reagents need to be added during the synthesis process, which can easily produce harmful residues. Using coal tar as a carbon source results in complex compositions containing harmful substances such as polycyclic aromatic hydrocarbons. Although this can reduce costs, the safety of the carbon dots cannot be fully verified, and their use in agricultural product preservation poses food safety risks. At the same time, carbon dots prepared by existing chemical synthesis or industrial byproducts are easily degraded under light conditions, releasing molecules with cytotoxicity, further limiting their application in the field of agricultural product preservation. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A preservative for agricultural products based on carbon dots derived from traditional Chinese medicinal materials includes carbon dots derived from traditional Chinese medicinal materials and a solvent. The carbon dots derived from traditional Chinese medicinal materials are one of the following: Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis. The concentration of the carbon dots derived from traditional Chinese medicinal materials in the preservative is 0.1-1.0 mg / mL. The solvent is deionized water.

[0006] As a preferred embodiment of the agricultural product preservative based on carbon dots from traditional Chinese medicinal materials according to the present invention, it further includes: 0.5-1.0% of a film-forming agent, wherein the film-forming agent is one of chitosan and sodium alginate.

[0007] As a preferred embodiment of the agricultural product preservative based on carbon dots from traditional Chinese medicine materials described in this invention, it further includes: 0.1-0.3% of natural plant antibacterial extract, wherein the natural plant antibacterial extract is one of peppermint extract, artemisia extract, and clove extract.

[0008] A method for preparing an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials includes the following specific steps: S1, Preparation of carbon dots from Chinese medicinal materials: S11, Pre-processing of Chinese medicinal materials: First, select at least one of Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis and Angelica sinensis as raw materials. Then, wash the Chinese medicinal materials with deionized water and dry them in an oven at 60-80℃ for 1-2 hours. After that, pulverize them with a high-speed pulverizer and pass them through an 80-100 mesh sieve to obtain uniform Chinese medicinal material powder. S12, hydrothermal synthesis: Mix the Chinese herbal medicine powder with deionized water, stir evenly, and react at 150-200℃ for 4-12 hours. After the reaction is completed, cool naturally to room temperature to obtain a suspension. S13, Purification: First, place the suspension in a high-speed centrifuge and take the supernatant. Then, transfer the supernatant to a dialysis bag with a molecular weight cutoff of 1000-3500 Da and dialyze with deionized water for 24-48 hours, changing the deionized water 3-4 times during the process. After that, filter the dialyzed solution through a 0.20-0.24 μm microporous membrane to obtain the purified carbon dot solution. S14, directional retention and modification of active ingredients: First, add the extract of Chinese medicinal materials to the purified carbon dot solution and stir at a constant temperature of 30-40℃ for 30-60 minutes. Then, concentrate it to 1 / 2 of the original volume by vacuum rotary evaporation to obtain carbon dots from Chinese medicinal materials. S2, Preparation of agricultural product preservatives: S21, dissolve the carbon dots from the Chinese medicinal material in a solvent to prepare an aqueous solution with a concentration of 0.1-1.0 mg / mL; S22, when added to an aqueous solution with 0.5-1.0% film-forming agent and stirred until completely dissolved, forms a composite preservative; S23, add 0.1-0.3% of natural plant antibacterial extract to the compound preservative, and after stirring evenly, let it stand in the dark to obtain an agricultural product preservative.

[0009] As a preferred embodiment of the preparation method of an agricultural product preservative based on carbon dots of Chinese medicinal materials according to the present invention, in step S11, the following ingredients are used: Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis are used in proportions of 2-10 parts each: Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis.

[0010] As a preferred embodiment of the preparation method of an agricultural product preservative based on carbon dots from traditional Chinese medicine materials according to the present invention, in step S12, the mass ratio of traditional Chinese medicine powder to deionized water is set to 1:20-1:50.

[0011] As a preferred embodiment of the preparation method of an agricultural product preservative based on carbon dots from traditional Chinese medicine materials according to the present invention, in step S13, the speed of the high-speed centrifuge is set to 8000-12000 rpm, and the centrifugation time is set to 15-20 minutes.

[0012] As a preferred embodiment of the preparation method of an agricultural product preservative based on carbon dots from traditional Chinese medicine materials according to the present invention, in step S14, the mass ratio of the purified carbon dot solution to the extract of traditional Chinese medicine materials is set to 1:0.5, and the extract of traditional Chinese medicine materials is one of the following: Astragalus membranaceus extract, Glycyrrhiza uralensis extract, Lonicera japonica extract, Coptis chinensis extract, and Angelica sinensis extract.

[0013] As a preferred embodiment of the preparation method of an agricultural product preservative based on carbon dots from traditional Chinese medicinal materials according to the present invention, in step S23, the standing temperature is set to 25℃-30℃ and the standing time is set to 20-30 minutes.

[0014] An application of a preservative for agricultural products based on carbon dots derived from traditional Chinese medicinal materials in postharvest preservation of agricultural products, wherein the agricultural products are fruits or vegetables; the application method is soaking or spraying, the soaking time is 1-3 minutes, and after spraying, the product is naturally dried and stored at room temperature or low temperature.

[0015] Compared with existing technologies: 1. By adopting carbon point preservation technology from Chinese medicinal materials, there is no need to rely on high-energy-consuming physical storage equipment. It can achieve the preservation of various types of agricultural products, avoid damage to the quality of agricultural products caused by physical methods such as low temperature, and reduce preservation energy consumption and cost. 2. By preparing carbon dots using Chinese medicinal herbs as a carbon source, and relying on the synergistic effect of the natural active ingredients of Chinese medicinal herbs and carbon dots, it can achieve the effects of safe preservation of agricultural products, avoid the risk of excessive residues of chemical preservatives, prevent the development of microbial resistance, and ensure the safety of agricultural products for consumption. 3. By selecting traditional Chinese medicinal materials as the sole carbon source and optimizing the hydrothermal synthesis and purification process, the carbon dot preparation process can be made green and environmentally friendly, the carbon dot preparation cost can be reduced, the purity and safety of carbon dots can be improved, and the cytotoxicity caused by carbon dot photodegradation can be avoided. 4. By organically combining Chinese medicinal materials with carbon dot preparation and agricultural product preservation technology, the application value of by-products and low-grade medicinal materials of Chinese medicinal materials can be explored. This can achieve diversified utilization of Chinese medicinal material resources, enhance the economic value of Chinese medicinal materials, and promote the high-value development of Chinese medicinal material resources. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below.

[0017] Example 1: This invention provides an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials, comprising carbon dots derived from traditional Chinese medicinal materials and a solvent. The carbon dots derived from traditional Chinese medicinal materials are one of the following: Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis, and the concentration of the carbon dots derived from traditional Chinese medicinal materials in the preservative is 0.1 mg / mL; the solvent is deionized water.

[0018] It also includes 0.5% of a film-forming agent, wherein the film-forming agent is one of chitosan and sodium alginate.

[0019] It also includes: 0.1% of natural plant antibacterial extract, wherein the natural plant antibacterial extract is one of peppermint extract, artemisia extract, and clove extract.

[0020] A method for preparing an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials includes the following specific steps: S1, Preparation of carbon dots from Chinese medicinal materials: S11, Pre-processing of Chinese medicinal materials: First, select at least one of Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis as raw materials. Then, wash the Chinese medicinal materials with deionized water to remove impurities and surface stains, and dry them in a 60℃ oven for 1 hour. After that, pulverize them with a high-speed pulverizer and pass them through an 80-mesh sieve to obtain uniform Chinese medicinal material powder. Among them, the proportions of Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis are set as follows: 2 parts Astragalus membranaceus, 2 parts Glycyrrhiza uralensis, 2 parts Lonicera japonica, 2 parts Coptis chinensis, and 2 parts Angelica sinensis. S12, hydrothermal synthesis: The powdered Chinese medicinal materials are mixed with deionized water, stirred evenly, and reacted at 150°C for 4 hours. After the reaction is completed, the mixture is naturally cooled to room temperature to obtain a suspension. The mass ratio of the powdered Chinese medicinal materials to the deionized water is set to 1:20. S13, Purification: First, place the suspension in a high-speed centrifuge and collect the supernatant. Then, transfer the supernatant to a dialysis bag with a molecular weight cutoff of 1000 Da and dialyze with deionized water for 24 hours, changing the deionized water 3 times during the process to remove small molecule impurities. After that, filter the dialyzed solution through a 0.20 μm microporous membrane to obtain the purified carbon dot solution. The speed of the high-speed centrifuge was set to 8000 rpm and the centrifugation time was set to 15 minutes. S14, Targeted Retention and Modification of Active Ingredients: First, the extract of traditional Chinese medicine was added to the purified carbon dot solution and stirred at a constant temperature of 30℃ for 30 minutes. Then, the solution was concentrated to 1 / 2 of its original volume by vacuum rotary evaporation to obtain carbon dots from traditional Chinese medicine. The mass ratio of the purified carbon dot solution to the extract of traditional Chinese medicine was set to 1:0.5, and the extract of traditional Chinese medicine was one of the following: Astragalus membranaceus extract, Glycyrrhiza uralensis extract, Lonicera japonica extract, Coptis chinensis extract, and Angelica sinensis extract. S2, Preparation of agricultural product preservatives: S21, dissolve the carbon dots from the Chinese medicinal material in a solvent to prepare an aqueous solution with a concentration of 0.1 mg / mL; S22, when 0.5% of a film-forming agent is added to an aqueous solution and stirred until completely dissolved, forms a composite preservative; S23, 0.1% of natural plant antibacterial extract is added to the compound preservative, and after stirring evenly, it is left to stand in the dark to obtain an agricultural product preservative; wherein, the standing temperature is set at 25℃ and the standing time is set at 20 minutes.

[0021] An application of a preservative for agricultural products based on carbon dots derived from traditional Chinese medicinal materials in postharvest preservation of agricultural products, wherein the agricultural products are fruits or vegetables; the application method is soaking or spraying, the soaking time is 1 minute, and after spraying, the product is naturally dried and stored at room temperature or low temperature.

[0022] Example 2: This invention provides an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials, comprising carbon dots derived from traditional Chinese medicinal materials and a solvent. The carbon dots derived from traditional Chinese medicinal materials are one of the following: Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis, and the concentration of the carbon dots derived from traditional Chinese medicinal materials in the preservative is 0.5 mg / mL; the solvent is deionized water.

[0023] It also includes 0.75% of a film-forming agent, wherein the film-forming agent is one of chitosan and sodium alginate.

[0024] It also includes: 0.2% of natural plant antibacterial extract, wherein the natural plant antibacterial extract is one of peppermint extract, artemisia extract, and clove extract.

[0025] A method for preparing an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials includes the following specific steps: S1, Preparation of carbon dots from Chinese medicinal materials: S11, Pre-processing of Chinese medicinal materials: First, select at least one of Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis as raw materials. Then, wash the Chinese medicinal materials with deionized water to remove impurities and surface stains, and dry them in a 70℃ oven for 1.5 hours. After that, pulverize them with a high-speed pulverizer and pass them through a 90-mesh sieve to obtain uniform Chinese medicinal material powder. Among them, the proportions of Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis are set as follows: 6 parts Astragalus membranaceus, 6 parts Glycyrrhiza uralensis, 6 parts Lonicera japonica, 6 parts Coptis chinensis, and 6 parts Angelica sinensis. S12, hydrothermal synthesis: The powdered Chinese medicinal materials are mixed with deionized water, stirred evenly, and reacted at 175℃ for 8 hours. After the reaction is completed, the mixture is naturally cooled to room temperature to obtain a suspension. The mass ratio of the powdered Chinese medicinal materials to the deionized water is set to 1:35. S13, Purification: First, place the suspension in a high-speed centrifuge and collect the supernatant. Then, transfer the supernatant to a dialysis bag with a molecular weight cutoff of 2250 Da and dialyze with deionized water for 36 hours, changing the deionized water 3 times during the process to remove small molecule impurities. After that, filter the dialyzed solution through a 0.22 μm microporous membrane to obtain the purified carbon dot solution. The speed of the high-speed centrifuge was set to 10000 rpm and the centrifugation time was set to 17.5 minutes. S14, Targeted Retention and Modification of Active Ingredients: First, the extract of traditional Chinese medicine was added to the purified carbon dot solution and stirred at a constant temperature of 35℃ for 45 minutes. Then, the solution was concentrated to 1 / 2 of its original volume by vacuum rotary evaporation to obtain carbon dots from traditional Chinese medicine. The mass ratio of the purified carbon dot solution to the extract of traditional Chinese medicine was set to 1:0.5, and the extract of traditional Chinese medicine was one of the following: Astragalus membranaceus extract, Glycyrrhiza uralensis extract, Lonicera japonica extract, Coptis chinensis extract, and Angelica sinensis extract. S2, Preparation of agricultural product preservatives: S21, dissolve the carbon dots from the Chinese medicinal material in a solvent to prepare an aqueous solution with a concentration of 0.5 mg / mL; S22, when 0.75% of a film-forming agent is added to an aqueous solution and stirred until completely dissolved, forms a composite preservative; S23, 0.2% of natural plant antibacterial extract is added to the compound preservative, and after stirring evenly, it is placed in the dark to obtain an agricultural product preservative; wherein, the standing temperature is set at 27.5℃ and the standing time is set at 25 minutes.

[0026] An application of a preservative for agricultural products based on carbon dots derived from traditional Chinese medicinal materials in postharvest preservation of agricultural products, wherein the agricultural products are fruits or vegetables; the application method is soaking or spraying, the soaking time is 1-3 minutes, and after spraying, the product is naturally dried and stored at room temperature or low temperature.

[0027] Example 3: This invention provides an agricultural product preservative based on carbon dots derived from traditional Chinese medicine, comprising carbon dots derived from traditional Chinese medicine and a solvent. The carbon dots derived from traditional Chinese medicine are one of the following: Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis, and the concentration of the carbon dots derived from traditional Chinese medicine in the preservative is 1.0 mg / mL; the solvent is deionized water.

[0028] It also includes: 1.0% of a film-forming agent, wherein the film-forming agent is one of chitosan and sodium alginate.

[0029] It also includes: 0.3% of natural plant antibacterial extract, wherein the natural plant antibacterial extract is one of peppermint extract, artemisia extract, and clove extract.

[0030] A method for preparing an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials includes the following specific steps: S1, Preparation of carbon dots from Chinese medicinal materials: S11, Pre-processing of Chinese medicinal materials: First, select at least one of Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis as raw materials. Then, wash the Chinese medicinal materials with deionized water to remove impurities and surface stains, and dry them in an 80℃ oven for 2 hours. After that, pulverize them with a high-speed pulverizer and pass them through a 100-mesh sieve to obtain uniform Chinese medicinal material powder. Among them, the proportions of Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis are set as follows: 10 parts of Astragalus membranaceus, 10 parts of Glycyrrhiza uralensis, 10 parts of Lonicera japonica, 10 parts of Coptis chinensis, and 10 parts of Angelica sinensis. S12, hydrothermal synthesis: The powdered Chinese medicinal materials are mixed with deionized water, stirred evenly, and reacted at 200℃ for 12 hours. After the reaction is completed, the mixture is naturally cooled to room temperature to obtain a suspension. The mass ratio of the powdered Chinese medicinal materials to the deionized water is set to 1:50. S13, Purification: First, place the suspension in a high-speed centrifuge and collect the supernatant. Then, transfer the supernatant to a dialysis bag with a molecular weight cutoff of 3500 Da and dialyze with deionized water for 48 hours, changing the deionized water 4 times during this period to remove small molecule impurities. After that, filter the dialyzed solution through a 0.24 μm microporous membrane to obtain the purified carbon dot solution. The speed of the high-speed centrifuge was set to 12000 rpm and the centrifugation time was set to 20 minutes. S14, Targeted Retention and Modification of Active Ingredients: First, the extract of traditional Chinese medicine was added to the purified carbon dot solution and stirred at a constant temperature of 40℃ for 60 minutes. Then, the solution was concentrated to 1 / 2 of its original volume by vacuum rotary evaporation to obtain carbon dots from traditional Chinese medicine. The mass ratio of the purified carbon dot solution to the extract of traditional Chinese medicine was set to 1:0.5, and the extract of traditional Chinese medicine was one of the following: Astragalus membranaceus extract, Glycyrrhiza uralensis extract, Lonicera japonica extract, Coptis chinensis extract, and Angelica sinensis extract. S2, Preparation of agricultural product preservatives: S21, dissolve the carbon dots from the Chinese medicinal material in a solvent to prepare an aqueous solution with a concentration of 1.0 mg / mL; S22, when 1.0% of a film-forming agent is added to an aqueous solution and stirred until completely dissolved, forms a composite preservative; S23, 0.3% of natural plant antibacterial extract is added to the compound preservative, and after stirring evenly, it is left to stand in the dark to obtain an agricultural product preservative; wherein, the standing temperature is set at 30℃ and the standing time is set at 30 minutes.

[0031] An application of a preservative for agricultural products based on carbon dots derived from traditional Chinese medicinal materials in postharvest preservation of agricultural products, wherein the agricultural products are fruits or vegetables; the application method is soaking or spraying, the soaking time is 3 minutes, and after spraying, the product is naturally dried and stored at room temperature or low temperature.

[0032] The following data were obtained by comparing the agricultural product preservatives prepared in Examples 1-3 above:

[0033] As shown in the table above, the agricultural product preservatives prepared in Examples 1-3 all showed good performance in terms of spoilage rate. After use, Example 2 showed the best effect.

[0034] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A preservative for agricultural products based on carbon dots derived from traditional Chinese medicinal materials, characterized in that, The product includes carbon dots derived from Chinese medicinal materials and a solvent. The carbon dots derived from Chinese medicinal materials are one of the following: Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis. The concentration of the carbon dots derived from Chinese medicinal materials in the preservative is 0.1-1.0 mg / mL. The solvent is deionized water.

2. The agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials according to claim 1, characterized in that, Also includes: 0.5-1.0% of a film-forming agent, wherein the film-forming agent is one of chitosan and sodium alginate.

3. The agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials according to claim 1, characterized in that, Also includes: 0.1-0.3% of natural plant antibacterial extracts, wherein the natural plant antibacterial extracts are one of peppermint extract, artemisia extract, and clove extract.

4. A method for preparing an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials, characterized in that, The specific steps are as follows: S1, Preparation of carbon dots from Chinese medicinal materials: S11, Pre-processing of Chinese medicinal materials: First, select at least one of Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis and Angelica sinensis as raw materials. Then, wash the Chinese medicinal materials with deionized water and dry them in an oven at 60-80℃ for 1-2 hours. After that, pulverize them with a high-speed pulverizer and pass them through an 80-100 mesh sieve to obtain uniform Chinese medicinal material powder. S12, hydrothermal synthesis: Mix the Chinese herbal medicine powder with deionized water, stir evenly, and react at 150-200℃ for 4-12 hours. After the reaction is completed, cool naturally to room temperature to obtain a suspension. S13, Purification: First, place the suspension in a high-speed centrifuge and take the supernatant. Then, transfer the supernatant to a dialysis bag with a molecular weight cutoff of 1000-3500 Da and dialyze with deionized water for 24-48 hours, changing the deionized water 3-4 times during the process. After that, filter the dialyzed solution through a 0.20-0.24 μm microporous membrane to obtain the purified carbon dot solution. S14, directional retention and modification of active ingredients: First, add the extract of Chinese medicinal materials to the purified carbon dot solution and stir at a constant temperature of 30-40℃ for 30-60 minutes. Then, concentrate it to 1 / 2 of the original volume by vacuum rotary evaporation to obtain carbon dots from Chinese medicinal materials. S2, Preparation of agricultural product preservatives: S21, dissolve the carbon dots from the Chinese medicinal material in a solvent to prepare an aqueous solution with a concentration of 0.1-1.0 mg / mL; S22, in an aqueous solution, is mixed with 0.5-1.0% of a film-forming agent and stirred until completely dissolved to form a composite preservative; S23, add 0.1-0.3% of natural plant antibacterial extract to the compound preservative, and after stirring evenly, let it stand in the dark to obtain an agricultural product preservative.

5. The method for preparing an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials according to claim 4, characterized in that, In S11, the following ingredients are used in proportion: Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis, with each ingredient being 2-10 parts: Astragalus membranaceus, Glycyrrhiza uralensis, Lonicera japonica, Coptis chinensis, and Angelica sinensis.

6. The method for preparing an agricultural product preservative based on carbon dots from traditional Chinese medicinal materials according to claim 4, characterized in that, In step S12, the mass ratio of Chinese medicinal herb powder to deionized water is set to 1:20-1:

50.

7. The method for preparing an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials according to claim 4, characterized in that, In step S13, the speed of the high-speed centrifuge is set to 8000-12000 rpm, and the centrifugation time is set to 15-20 minutes.

8. The method for preparing an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials according to claim 4, characterized in that, In step S14, the mass ratio of the purified carbon dot solution to the herbal extract is set to 1:0.5, and the herbal extract is one of the following: Astragalus membranaceus extract, Glycyrrhiza uralensis extract, Lonicera japonica extract, Coptis chinensis extract, and Angelica sinensis extract.

9. The method for preparing an agricultural product preservative based on carbon dots derived from traditional Chinese medicinal materials according to claim 4, characterized in that, In step S23, the settling temperature is set to 25℃-30℃, and the settling time is set to 20-30 minutes.

10. The application of a preservative for agricultural products based on carbon dots derived from traditional Chinese medicinal materials in postharvest preservation of agricultural products, characterized in that... The agricultural products mentioned are fruits or vegetables; the application method is soaking or spraying. The soaking time is 1-3 minutes, and after spraying, they are naturally dried and stored at room temperature or low temperature.

Images