Preparation method of resveratrol and application of resveratrol in meat preservation

Abstract

The invention belongs to the technical field of resveratrol synthesis, and particularly relates to a preparation method of resveratrol and application of resveratrol in meat preservation. The method comprises the following steps: taking 3, 5-dimethoxybenzoic acid as a raw material, and carrying out acylation reaction to obtain 3, 5-dimethoxybenzoyl chloride. Then reacting with p-acetoxystyrene to generate 3, 3 '-dihydroxy-3, 3'-dihydroxy-3 The preparation method comprises the following steps: taking 1, 5-dimethoxy-4 '-acetoxystilbene as a raw material, hydrolyzing and demethylating to obtain resveratrol, and preparing resveratrol lipid nanoparticle suspension by taking resveratrol, a ZIF-8 / chitosan compound, compound lipid, cholesterol, epsilon-polylysine, ascorbyl palmitate and phosphate buffer saline as raw materials. High load and controlled release of resveratrol are achieved, and the problems that resveratrol is poor in water solubility and prone to oxidation are solved.

Description

A method for preparing resveratrol and its application in meat preservation. Technical Field

[0001] This invention belongs to the field of resveratrol synthesis technology, specifically relating to a method for preparing resveratrol and its application in meat preservation. Background Technology

[0002] Resveratrol (RESV) is a natural polyphenol compound widely found in plants such as grapes and Japanese knotweed, possessing various biological activities including antioxidant, anti-inflammatory, and anti-aging properties. In the health supplement industry, it is used for anti-aging, cardiovascular protection, and blood sugar management. In pharmaceutical research, its potential for anti-tumor activity, neuroprotection, and immunomodulation is attracting significant attention, particularly in adjuvant chemotherapy and Alzheimer's disease prevention. The cosmetics industry utilizes its properties of promoting collagen synthesis and inhibiting melanin production to develop anti-wrinkle and whitening products. Furthermore, it is used in agricultural feed additives, food preservation, and oral care. Resveratrol's multifunctional properties make it a star ingredient for cross-disciplinary applications.

[0003] Chinese patent CN120289277A discloses a method for preparing resveratrol, resveratrol and its applications. The method involves dissolving compound 1 in an organic solvent and reacting it to obtain compound 2. Then, chlorobenzene and a catalyst are added, and under ultraviolet light, compound 2 undergoes a Friedel-Crafts reaction with chlorobenzene to obtain compound 3. Compound 3 is then oxidized and reduced to obtain 1-(4-phenol)-2-(3,5-dihydroxyphenyl)ethanol, and the hydroxyl group is eliminated to obtain resveratrol. By using ultraviolet light to assist the Friedel-Crafts reaction, the content of byproducts in the Friedel-Crafts reaction is reduced, simplifying the preparation process of resveratrol and lowering its preparation cost. Chinese patent CN118666649A discloses a novel method for synthesizing resveratrol from 3,5-dimethoxybenzaldehyde. This method utilizes tetrafluorothiamane salt as a novel coupling agent, replacing halogen reagents, in the Heck reaction under the catalysis of the highly efficient phosphine ligand AntPhos, to synthesize resveratrol. This method offers mild reaction conditions, ease of operation, low-cost catalysts, and high yields. However, the synthetic routes provided in the aforementioned prior art are lengthy and have poor industrial applicability.

[0004] Therefore, there is a need to provide a simple and high-yield method for preparing resveratrol, as well as a highly stable and long-lasting resveratrol lipid nanoparticle, to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing resveratrol and its application in meat preservation.

[0006] To achieve the purpose of this invention, the following technical solution is adopted: A method for preparing resveratrol, comprising the following steps: (1) using 3,5-dimethoxybenzoic acid as raw material, dissolving it in an organic solvent and reacting it with an acylation reagent to obtain 3,5-dimethoxybenzoyl chloride; (2) using 3,5-dimethoxybenzoyl chloride and p-acetoxystyrene as raw materials, reacting them under the action of a ligand and a catalyst to obtain 3,5-dimethoxy-4'-acetoxystilbene; (3) using 3,5-dimethoxy-4'-acetoxystilbene as raw material, hydrolyzing and demethylating it to obtain the resveratrol.

[0007] Preferably, the organic solvent is at least one of methanol, acetone, toluene, and dimethyl sulfoxide; and the acylation reagent is at least one of oxalyl chloride, thionyl chloride, and phosphorus pentachloride.

[0008] Preferably, the ligand is triphenylphosphine; the catalyst is at least one of Pd(PPh3)4, Pd2(dba)3, and Pd(OAc)2.

[0009] Preferably, the alkali used for hydrolysis is at least one of NaOH, KOH, and LiOH, and the acid used is at least one of HCl, HF, and H2SO4; the reagent used for demethylation is at least one of methanesulfonic acid, BBr3, and AlCl3.

[0010] The second objective of this invention is to provide a resveratrol prepared by a method for preparing resveratrol as described in any of the above technical solutions.

[0011] The third objective of this invention is to provide a resveratrol lipid nanoparticle suspension, wherein the raw materials of the resveratrol lipid nanoparticle suspension include resveratrol, ZIF-8 / chitosan complex, complex lipids, cholesterol, ε-polylysine, ascorbate palmitate, and phosphate buffered saline as described in the above technical solution.

[0012] The fourth objective of this invention is to provide a method for preparing resveratrol lipid nanoparticle suspension, comprising the following steps: S1, dissolving zinc nitrate hexahydrate and 2-methylimidazole in deionized water, stirring at room temperature for 20-30 min, adding chitosan, raising the temperature to 45-55℃, stirring for 2-4 h, and obtaining ZIF-8 / chitosan complex after centrifugation, washing, and drying; S2, dissolving resveratrol in chloroform-methanol solution, adding ZIF-8 / chitosan complex, stirring at room temperature for 10-15 h, then adding composite lipids, cholesterol, ε-polylysine, and ascorbate palmitate, rotary evaporating to form a film, then adding phosphate buffered saline containing Tween 80, vortexing, and sonicating in an ice bath to obtain a milky white suspension, which is the resveratrol lipid nanoparticle suspension.

[0013] Preferably, the composite lipid is a mixture of lecithin, sphingomyelin, and phosphatidylethanolamine-polyethylene glycol 2000-biotin in a mass ratio of 4-6:2-3:1.

[0014] Preferably, the ultrasonic conditions are: ultrasonic power: 200-240W, ultrasonic time: 5-15min, ultrasonic mode: 10s on / 10s off.

[0015] Another objective of this invention is to provide the application of the above-mentioned resveratrol lipid nanoparticle suspension in meat preservation.

[0016] This invention offers the following advantages: The resveratrol preparation method provided by this invention is simple in steps, has mild reaction conditions, and achieves a total yield of 88%. All reagents used are conventional raw materials, making it easy for industrial production. By using resveratrol, ZIF-8 / chitosan complex, composite lipids, cholesterol, ε-polylysine, ascorbate palmitate, and phosphate-buffered saline as raw materials, a resveratrol lipid nanoparticle suspension is prepared, achieving high loading and controlled release of resveratrol and solving the problems of poor water solubility and easy oxidation of resveratrol. Attached Figure Description

[0017] Figure 1 shows the total bacterial count (log) of Examples 4 to 7 and Comparative Examples 1 to 3 of the present invention. 10 Figure 2 shows the change of pH value with refrigeration time for Examples 4 to 7 and Comparative Examples 1 to 3 of the present invention; Figure 3 shows the change of volatile basic nitrogen (TVB-N) content with refrigeration time for Examples 4 to 7 and Comparative Examples 1 to 3 of the present invention; Figure 4 shows the change of thiobarbituric acid reactant (TBARS) content with refrigeration time for Examples 4 to 7 and Comparative Examples 1 to 3 of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] Resveratrol is a natural polyphenol compound with various biological activities such as antioxidation, anti-inflammation, and antibacterial properties, and it has broad application prospects in the field of food preservation. Currently, the preparation of resveratrol mainly involves two methods: plant extraction and chemical synthesis. Plant extraction relies on raw materials such as grapes and Japanese knotweed, is limited by season and production location, and has a low yield, making it difficult to meet industrial needs. Chemical synthesis suffers from drawbacks such as cumbersome steps, harsh reaction conditions, and low product purity. Therefore, the present invention provides a method for preparing resveratrol, comprising the following steps: (1) using 3,5-dimethoxybenzoic acid as a raw material, dissolving it in an organic solvent and reacting it with an acylation reagent to obtain 3,5-dimethoxybenzoyl chloride; (2) using 3,5-dimethoxybenzoyl chloride and p-acetoxystyrene as raw materials, reacting them under the action of a ligand and a catalyst to obtain 3,5-dimethoxy-4'-acetoxystilbene; (3) using 3,5-dimethoxy-4'-acetoxystilbene as a raw material, hydrolyzing and demethylating it to obtain the resveratrol.

[0020] Specifically, step (1) involves adding 3,5-dimethoxybenzoic acid and an organic solvent to a three-necked flask equipped with a reflux condenser and a drying tube, stirring in an ice-water bath, adding the acylation reagent dropwise using a constant pressure funnel, removing the ice bath after the addition is complete, adding DMF, refluxing at 70-80℃ for 2-3 hours, detecting the reaction endpoint by TLC, and removing the organic solvent and acylation reagent by vacuum distillation after the reaction solution is cooled to room temperature to obtain a pale yellow oily crude product, which is 3,5-dimethoxybenzoyl chloride.

[0021] Step (2) is as follows: The obtained 3,5-dimethoxybenzoyl chloride is directly added to a dry Schlenk reaction flask. In the Schlenk flask, p-acetoxystyrene, catalyst, ligand, anhydrous sodium acetate, and solvent DMF are added in sequence. The reaction system is evacuated and purged with nitrogen gas, and the cycle is repeated more than 3 times. Then, the mixture is stirred and refluxed in an oil bath at 80-90℃. After the reaction is completed, the mixture is cooled to room temperature and saturated ammonium chloride solution is slowly added to quench the reaction. The mixture is extracted with ethyl acetate, and the organic phases are combined. The organic phases are then washed with saturated brine and water in sequence, dried with anhydrous sodium sulfate, and the solvent is removed by rotary evaporation to obtain a brownish-yellow solid, which is 3,5-dimethoxy-4'-acetoxystyrene.

[0022] Step (3) is as follows: In a three-necked flask equipped with a reflux condenser, add 3,5-dimethoxy-4'-acetoxystilbene and 95% ethanol, stir and heat until dissolved, add alkaline solution dropwise, reflux and stir at 70-80℃ for 2-4 hours, cool and place in an ice bath at 0-5℃, add acid solution dropwise to adjust pH to 4-5, a white precipitate is precipitated, centrifuge, filter and dry to obtain a white solid, dissolve it in dichloromethane, stir until dissolved, add anhydrous AlCl3 under nitrogen protection, stir for 20-30 minutes, add a suspension made of sodium ethyl sulfate and dichloromethane dropwise in an ice bath at 0℃, stir for 2-4 hours, wash with alkaline solution and saturated saline solution in sequence, dry with anhydrous sodium sulfate, filter and recrystallize to obtain resveratrol.

[0023] In step (1), the organic solvent is at least one of methanol, acetone, toluene, and dimethyl sulfoxide, preferably toluene, which can fully dissolve 3,5-dimethoxybenzoic acid and has good compatibility with the subsequent acylation reagent; the acylation reagent is at least one of oxalyl chloride, thionyl chloride, and phosphorus pentachloride, preferably thionyl chloride, which has high reactivity and easy removal of byproducts.

[0024] Toluene, as an aprotic polar solvent, can enhance the solubility of 3,5-dimethoxybenzoic acid while avoiding reaction with acylation reagents; thionyl chloride, as an acylation reagent, reacts with carboxyl groups to generate acyl chlorides without residual impurities, thus improving product purity.

[0025] In step (2), the ligand is triphenylphosphine, which can form a stable complex with the catalyst to enhance the activity and selectivity of the catalyst; the catalyst is at least one of Pd(PPh3)4, Pd2(dba)3, and Pd(OAc)2, preferably Pd(OAc)2, which has high catalytic efficiency and relatively low cost.

[0026] In step (3), the alkali used for hydrolysis is at least one of NaOH, KOH, and LiOH, preferably NaOH; the acid used is at least one of HCl, HF, and H2SO4, preferably HCl; the reagent used for demethylation is at least one of methanesulfonic acid, BBr3, and AlCl3, preferably AlCl3, which has high demethylation efficiency and mild reaction conditions.

[0027] NaOH, as a strong base, can rapidly break the ester bond of acetoxy groups to generate hydroxyl groups; HCl is used to neutralize excess base, causing intermediates to precipitate and preventing subsequent demethylation reactions from being interfered with by the base; AlCl3, as a Lewis acid, can form complexes with methoxy groups, promoting methyl removal.

[0028] A resveratrol is prepared by a resveratrol preparation method as described in any of the above technical solutions.

[0029] A resveratrol lipid nanoparticle suspension, comprising resveratrol, a ZIF-8 / chitosan complex, composite lipids, cholesterol, ε-polylysine, ascorbate palmitate, and phosphate-buffered saline. The composite lipids are a mixture of lecithin, sphingomyelin, and phosphatidylethanolamine-polyethylene glycol 2000-biotin in a mass ratio of 4-6:2-3:1. The ZIF-8 / chitosan complex serves as the core carrier, enabling high loading and controlled release of resveratrol; the composite lipids construct a lipid shell, enhancing nanoparticle stability; cholesterol regulates lipid membrane fluidity, reducing resveratrol leakage; ε-polylysine synergistically inhibits bacteria with resveratrol, enhancing the antibacterial effect; and ascorbate palmitate possesses antioxidant properties, protecting resveratrol from oxidation.

[0030] The method for preparing resveratrol lipid nanoparticles is characterized by the following steps: S1, dissolving zinc nitrate hexahydrate and 2-methylimidazole in deionized water, stirring at room temperature for 20-30 min to form a precursor solution, adding chitosan (degree of deacetylation > 85%), raising the temperature to 45-55℃, stirring for 2-4 h, and after the reaction is completed, centrifuging, washing with anhydrous ethanol, and vacuum drying to obtain ZIF-8 / chitosan complex; S2, dissolving resveratrol in chloroform-methanol solution, adding ZIF-8 / chitosan complex, stirring at room temperature for 10-15 h, then adding composite lipids, cholesterol, ε-polylysine, and ascorbate palmitate, rotary evaporating to form a film, then adding phosphate buffered saline containing Tween 80 at 50-70℃, vortexing, and then sonicating in an ice bath to obtain a milky white suspension, which is the resveratrol lipid nanoparticle suspension.

[0031] In the above steps, the volume ratio of chloroform-methanol solution is 1:1-3:1, and the ultrasonic conditions are: ultrasonic power: 200-240W, ultrasonic time: 5-15min, ultrasonic mode: 10s on / 10s off. This ultrasonic mode avoids excessive temperature during ultrasonication, which could lead to lipid membrane rupture and resveratrol oxidation. Zinc nitrate hexahydrate and 2-methylimidazole form a ZIF-8 porous structure through coordination bonds. The amino groups in chitosan molecules coordinate with the carboxyl groups on the surface of ZIF-8, and chitosan molecules are cross-linked through hydrogen bonds to form a ZIF-8 / chitosan complex. Resveratrol fills the pores of ZIF-8 through molecular diffusion and hydrogen bonding, achieving a high loading. During rotary evaporation, the chloroform-methanol solvent evaporates, and the composite lipids, cholesterol, and other components form a uniform lipid film on the carrier surface. Vortex oscillation causes the lipid film to detach, and ultrasonic treatment further refines the particle size, resulting in a uniform nano-suspension.

[0032] Application of resveratrol lipid nanoparticle suspension in meat preservation. The prepared resveratrol lipid nanoparticle suspension was uniformly sprayed onto the surface of meat at a spraying rate of 80-100 μL / cm². 2 The meat includes livestock and poultry meat and aquatic meat, preferably at least one of pork, beef, mutton and chicken.

[0033] This invention provides a method for preparing resveratrol, the specific reaction process of which is as follows: .

[0034] Example 1: Synthesis of 3,5-Dimethoxybenzoyl chloride. 50 g of 3,5-dimethoxybenzoic acid and 300 ml of anhydrous toluene were added to a three-necked flask equipped with a reflux condenser and a drying tube. The mixture was stirred in an ice-water bath, and 100 ml of thionyl chloride (SOCl2) was slowly added dropwise using a constant-pressure funnel. After the addition was complete, the ice bath was removed. 1 ml of DMF was added dropwise, and the mixture was refluxed at 75°C for 2.5 h. The reaction endpoint was detected by TLC. After the reaction solution was cooled to room temperature, toluene and SOCl2 were removed by vacuum distillation, yielding 49.6 g of a pale yellow, oily crude product, 3,5-dimethoxybenzoyl chloride, with a yield of 90%.

[0035] Example 2: Synthesis of Dimethoxy-4'-acetoxystilbene. 49.6 g of 3,5-dimethoxybenzoyl chloride was directly added to a dry Schlenk flask. 38.12 g of p-oxyacetylstyrene, 2.43 g of palladium acetate (Pd(OAc)₂, 5 mol%), 5.67 g of triphenylphosphine (PPh₃, 10 mol%) as ligands, 35.52 g of anhydrous sodium acetate as base, and 400 mL of anhydrous DMF as solvent were added sequentially to the Schlenk flask. The reaction system was evacuated and purged with nitrogen, cyclically repeated four times. The mixture was stirred and refluxed in an oil bath at 85 °C for 8 h. After the reaction was complete, the mixture was cooled to room temperature, and a saturated ammonium chloride solution was slowly added to quench the reaction. The mixture was extracted with ethyl acetate (3 × 30 mL), and the organic phases were combined. The organic phases were washed sequentially with saturated brine (20 mL) and water (20 mL), and dried over anhydrous sodium sulfate. The solvent was removed by rotary evaporation to give 54.55 g of brownish-yellow solid 3,5-dimethoxy-4'-acetoxystilbene, with a yield of 74%.

[0036] Example 3: Synthesis of Resveratrol In a 1L three-necked flask equipped with a reflux condenser, 54.55g of 3,5-dimethoxy-4'-acetoxystilbene was added, followed by 600mL of 95% ethanol. The mixture was stirred and heated until dissolved. 50mL of 30% NaOH solution was slowly added dropwise to the ethanol solution in the flask. The mixture was refluxed at 75°C with stirring for 3 hours. After cooling, 10% dilute hydrochloric acid (HCl) was slowly added dropwise to adjust the pH to 4-5 in an ice bath at 0-5°C. A white precipitate formed. The precipitate was separated by centrifugation, filtered, and dried to obtain a white solid. This solid was dissolved in 900mL of dichloromethane (DCM) and stirred until dissolved. Under N2 protection, 141.61g of anhydrous AlCl3 was added, and the mixture was stirred for 30 minutes. Then, 85g of sodium ethyl sulfate (EtSNa) and 200mL of sodium ethyl sulfate (EtSNa) were added dropwise in an ice bath at 0°C. The suspension prepared by DCM was stirred for 2 hours and washed successively with 30% NaOH solution and saturated brine to remove acid, aluminum salt and water. After drying with anhydrous Na2SO4, the mixture was filtered, the solvent was evaporated, and crude resveratrol was obtained. The crude resveratrol was redissolved to remove color and recrystallized to obtain 35.55 g of refined resveratrol, with a yield of 88%.

[0037] Example 4: Application of 0.1% Resveratrol in Meat Product Preservation. Preparation method of 0.1% resveratrol lipid nanoparticle suspension: Includes the following steps: S1, Dissolve 1.0g zinc nitrate hexahydrate and 2.0g 2-methylimidazole in 50mL deionized water, stir at room temperature for 25min to form a precursor solution, add 0.2g chitosan, raise the temperature to 50℃, stir for 3h, centrifuge after reaction, wash with anhydrous ethanol (3×20mL), and vacuum dry at 45℃ for 8h to obtain the ZIF-8 / chitosan complex; S2, Dissolve 0.1g resveratrol in 25mL chloroform-methanol solution (chloroform 16.7mL + methanol 8.3mL), then add 0.3g... ZIF-8 / chitosan complex was stirred at room temperature for 12 hours. Then, 8.0 g of complex lipids (lecithin, sphingomyelin, and phosphatidylethanolamine-polyethylene glycol 2000-biotin mixed in a mass ratio of 5:2:1), 0.25 g of cholesterol, 0.1 g of ε-polylysine, and 0.05 g of ascorbate palmitate were added. The mixture was then rotary evaporated to form a film (rotary evaporation temperature 40℃, rotation speed 100 r / min). 100 mL of 60℃ phosphate-buffered saline (PBS) (containing 1% Tween 80 surfactant) was added. After vortexing, the mixture was sonicated in an ice bath for a cumulative 10 min (ultrasonic power: 220 W, sonication time: 10 min, sonication mode: 10 s on / 10 s off) to obtain a milky white suspension (particle size ≈ 200-400 nm), which is the resveratrol lipid nanoparticle suspension.

[0038] Take a piece of fresh pork leg and cut it into 5×5×1 cm pieces. 3 Size, spray the suspension onto the surface of the meat sample (dosage: 80 μL / cm) 2The preservation effect was tested at 4℃. Regular sampling and testing were conducted (days 0, 3, 6, 9, and 12). Microbiological analysis included: determination of total colony count (PCA); pH value: directly measured in meat homogenate; TVB-N (volatile basic nitrogen): assessing the degree of protein spoilage; TBARS (thiobarbituric acid reactants): reflecting the degree of lipid oxidation. Results are shown in Figures 1-4 for the corresponding test results of the 0.1% RESV component.

[0039] Example 5: Application of 0.3% Resveratrol in Meat Product Preservation. Preparation method of 0.3% resveratrol lipid nanoparticle suspension: Includes the following steps: S1, Dissolve 1.2g zinc nitrate hexahydrate and 2.4g 2-methylimidazole in 60mL deionized water, stir at room temperature for 25min to form a precursor solution, add 0.25g chitosan, raise the temperature to 50℃, stir for 3h, centrifuge after reaction, wash with anhydrous ethanol (3×25mL), and vacuum dry at 45℃ for 8h to obtain ZIF-8 / chitosan complex; S2, Dissolve 0.3g resveratrol in 30mL chloroform-methanol solution (20mL chloroform + 10mL methanol), add 0.9g ZIF-8... 8. Chitosan complex was stirred at room temperature for 12 hours, and then 9.0 g of complex lipids (lecithin, sphingomyelin, and phosphatidylethanolamine-polyethylene glycol 2000-biotin mixed in a mass ratio of 5:2:1), 0.3 g of cholesterol, 0.3 g of ε-polylysine, and 0.08 g of ascorbate palmitate were added. The mixture was then rotary evaporated to form a film (rotary evaporation temperature 40℃, rotation speed 100 r / min). Then, 100 mL of phosphate-buffered saline (PBS) (containing 1% Tween 80 surfactant) at 60℃ was added. After vortexing, the mixture was sonicated in an ice bath for a cumulative 10 min (ultrasonic power: 220 W, sonication time: 10 min, sonication mode: 10 s on / 10 s off) to obtain a milky white suspension (particle size ≈ 200-400 nm), which is the resveratrol lipid nanoparticle suspension.

[0040] Take a piece of fresh pork leg and cut it into 5×5×1 cm pieces. 3 Size, spray the suspension onto the surface of the meat sample (dosage: 80 μL / cm) 2 The preservation effect was tested at 4℃. Regular sampling and testing were conducted (days 0, 3, 6, 9, and 12). Microbiological analysis included: determination of total colony count (PCA); pH value: directly measured in meat homogenate; TVB-N (volatile basic nitrogen): assessing the degree of protein spoilage; TBARS (thiobarbituric acid reactants): reflecting the degree of lipid oxidation. Results are shown in Figures 1-4 for the corresponding test results of the 0.3% RESV component.

[0041] Example 6: Application of 0.5% Resveratrol in Meat Product Preservation. Preparation method of 0.5% resveratrol lipid nanoparticle suspension: Includes the following steps: S1, Dissolve 1.5g zinc nitrate hexahydrate and 3.0g 2-methylimidazole in 70mL deionized water, stir at room temperature for 25min to form a precursor solution, add 0.3g chitosan, raise the temperature to 50℃, stir for 3h, centrifuge after reaction, wash with anhydrous ethanol (3×30mL), and vacuum dry at 45℃ for 8h to obtain the ZIF-8 / chitosan complex; S2, Dissolve 0.5g resveratrol in 35mL chloroform-methanol solution (chloroform 23.3mL + methanol 11.7mL), then add 1.5g... ZIF-8 / chitosan complex was stirred at room temperature for 12 hours. Then, 10.0 g of complex lipids (lecithin, sphingomyelin, and phosphatidylethanolamine-polyethylene glycol 2000-biotin mixed in a mass ratio of 5:2:1), 0.35 g of cholesterol, 0.5 g of ε-polylysine, and 0.1 g of ascorbate palmitate were added. The mixture was then rotary evaporated to form a film (rotary evaporation temperature 40℃, rotation speed 100 r / min). 100 mL of 60℃ phosphate-buffered saline (PBS) (containing 1% Tween 80 surfactant) was added. After vortexing, the mixture was sonicated in an ice bath for a cumulative 10 min (ultrasonic power: 220 W, sonication time: 10 min, sonication mode: 10 s on / 10 s off) to obtain a milky white suspension (particle size ≈ 200-400 nm), which is the resveratrol lipid nanoparticle suspension.

[0042] Take a piece of fresh pork leg and cut it into 5×5×1 cm pieces. 3 Size, spray the suspension onto the surface of the meat sample (dosage: 80 μL / cm) 2 The preservation effect was tested at 4℃. Regular sampling and testing were conducted (days 0, 3, 6, 9, and 12). Microbiological analysis included: determination of total colony count (PCA); pH value: directly measured in meat homogenate; TVB-N (volatile basic nitrogen): assessing the degree of protein spoilage; TBARS (thiobarbituric acid reactants): reflecting the degree of lipid oxidation. Results are shown in Figures 1-4 for the corresponding test results of the 0.5% RESV component.

[0043] Example 7: Application of 1% Resveratrol in Meat Product Preservation. Preparation method of 1% resveratrol lipid nanoparticle suspension: Includes the following steps: S1, Dissolve 2.0g zinc nitrate hexahydrate and 4.0g 2-methylimidazole in 80mL deionized water, stir at room temperature for 25min to form a precursor solution, add 0.4g chitosan, raise the temperature to 50℃, stir for 3h, centrifuge after reaction, wash with anhydrous ethanol (3×35mL), and vacuum dry at 45℃ for 8h to obtain the ZIF-8 / chitosan complex; S2, Dissolve 1g resveratrol in 40mL chloroform-methanol solution (chloroform 26.7mL + methanol 13.3mL), then add 3.0g... ZIF-8 / chitosan complex was stirred at room temperature for 12 hours. Then, 12.0 g of complex lipids (lecithin, sphingomyelin, and phosphatidylethanolamine-polyethylene glycol 2000-biotin mixed in a mass ratio of 5:2:1), 0.4 g of cholesterol, 1.0 g of ε-polylysine, and 0.15 g of ascorbate palmitate were added. The mixture was then rotary evaporated to form a film (rotary evaporation temperature 40℃, rotation speed 100 r / min). 100 mL of 60℃ phosphate-buffered saline (PBS) (containing 1% Tween 80 surfactant) was added. After vortexing, the mixture was sonicated in an ice bath for a cumulative 10 min (ultrasonic power: 220 W, sonication time: 10 min, sonication mode: 10 s on / 10 s off) to obtain a milky white suspension (particle size ≈ 200-400 nm), which is the resveratrol lipid nanoparticle suspension.

[0044] Take a piece of fresh pork leg and cut it into 5×5×1 cm pieces. 3 Size, spray the suspension onto the surface of the meat sample (dosage: 80 μL / cm) 2 The preservation effect was tested at 4℃. Regular sampling and testing were conducted (days 0, 3, 6, 9, and 12). Microbiological analysis included: determination of total colony count (PCA); pH value: directly measured in meat homogenate; TVB-N (volatile basic nitrogen): assessing the degree of protein spoilage; TBARS (thiobarbituric acid reactants): reflecting the degree of lipid oxidation. Results are shown in Figures 1-4 for the corresponding test results of the 1% RESV components.

[0045] The difference between Comparative Example 1 (blank control group) and Example 4 is that only an equal amount of PBS (containing 1% Tween 80) was sprayed on.

[0046] Take the meat from the same thigh and cut it into 5×5×1 cm pieces. 3 Size, directly spray PBS (containing 1% Tween 80) onto the surface of the meat sample (dosage: 80 μL / cm). 2The preservation effect was tested by refrigeration at 4℃. Samples were taken periodically for testing (days 0, 3, 6, 9, and 12) to determine the total colony count (PCA), pH value, TVB-N, and TBARS value. The results are shown in Figures 1-4, corresponding to the test results of the blank control group.

[0047] Comparative Example 2 (carrier control group) is basically the same as Example 4, except that resveratrol is not added.

[0048] Preparation method of lipid nanoparticle suspension: including the following steps: S1, dissolve 1.0 g zinc nitrate hexahydrate and 2.0 g 2-methylimidazole in 50 mL deionized water, stir at room temperature for 25 min to form a precursor solution, add 0.2 g chitosan, raise the temperature to 50 °C, stir for 3 h, centrifuge after reaction, wash with anhydrous ethanol (3 × 20 mL), and vacuum dry at 45 °C for 8 h to obtain ZIF-8 / chitosan complex; S2, add 0.3 g to 25 mL chloroform-methanol solution (chloroform 16.7 mL + methanol 8.3 mL). ZIF-8 / chitosan complex was stirred at room temperature for 12 hours. Then, 8.0 g of complex lipids (lecithin, sphingomyelin, and phosphatidylethanolamine-polyethylene glycol 2000-biotin mixed in a mass ratio of 5:2:1), 0.25 g of cholesterol, 0.1 g of ε-polylysine, and 0.05 g of ascorbate palmitate were added. The mixture was then rotary evaporated to form a film (rotary evaporation temperature 40℃, rotation speed 100 r / min). 100 mL of 60℃ phosphate-buffered saline (PBS) (containing 1% Tween 80 surfactant) was added. After vortexing, the mixture was sonicated in an ice bath for a cumulative 10 min (ultrasonic power: 220 W, sonication time: 10 min, sonication mode: 10 s on / 10 s off) to obtain a milky white suspension, which is the lipid nanoparticle suspension (particle size ≈ 200-400 nm).

[0049] Take the meat from the same thigh and cut it into 5×5×1 cm pieces. 3 Size, spray the suspension onto the surface of the meat sample (dosage: 80 μL / cm) 2 The preservation effect was tested by refrigeration at 4℃. Samples were taken periodically for testing (days 0, 3, 6, 9, and 12) to determine the total colony count (PCA), pH value, TVB-N, and TBARS value. The results are shown in Figures 1-4, corresponding to the test results of the carrier control group.

[0050] The difference between Comparative Example 3 and Example 4 is that Comparative Example 3 was sprayed with a 0.3% potassium sorbate (PS) solution (positive control).

[0051] Take the meat from the same thigh and cut it into 5×5×1 cm pieces. 3 Size, spray 0.1% potassium sorbate solution onto the surface of the meat sample (dosage: 80 μL / cm). 2The preservation effect was tested by refrigeration at 4℃. Samples were taken periodically (on days 0, 3, 6, 9, and 12) to determine the total colony count (PCA), pH value, TVB-N, and TBARS value. The results are shown in Figures 1-4 for the test results corresponding to the 0.3% PS component.

[0052] Relevant test analysis: Table 1 The test results in Figures 1-4 were summarized and analyzed to draw the following conclusions, as shown in Table 1: 0.3-0.5% lipid nanoparticle resveratrol can effectively inhibit microbial proliferation and lipid oxidation, and control key spoilage indicators of meat within safe thresholds within 12 days. The effect is better than potassium sorbate, and it has the potential for natural and safe commercial application.

[0053] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0054] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing resveratrol, characterized in that, The process includes the following steps: using 3,5-dimethoxybenzoic acid as a raw material, dissolving it in an organic solvent and reacting it with an acylation reagent to obtain 3,5-dimethoxybenzoyl chloride; using 3,5-dimethoxybenzoyl chloride and p-acetoxystyrene as raw materials, reacting them under the action of a ligand and a catalyst to obtain 3,5-dimethoxy-4'-acetoxystilbene; and using 3,5-dimethoxy-4'-acetoxystilbene as a raw material, hydrolyzing and demethylating it to obtain the resveratrol.

2. The method for preparing resveratrol according to claim 1, characterized in that, The organic solvent is at least one of methanol, acetone, toluene, and dimethyl sulfoxide; the acylation reagent is at least one of oxaloyl chloride, thionyl chloride, and phosphorus pentachloride.

3. The method for preparing resveratrol according to claim 1, characterized in that, The ligand is triphenylphosphine; the catalyst is at least one of Pd(PPh3)4, Pd2(dba)3, and Pd(OAc)2.

4. The method for preparing resveratrol according to claim 1, characterized in that, The alkali used for hydrolysis is at least one of NaOH, KOH, and LiOH, and the acid used is at least one of HCl, HF, and H2SO4; the reagent used for demethylation is at least one of methanesulfonic acid, BBr3, and AlCl3.

5. A resveratrol, characterized in that, It was prepared using the method described in any one of claims 1-4.

6. A resveratrol lipid nanoparticle suspension, characterized in that, The raw materials for the resveratrol lipid nanoparticle suspension include resveratrol as described in claim 5, ZIF-8 / chitosan complex, complex lipids, cholesterol, ε-polylysine, ascorbate palmitate, and phosphate buffered saline.

7. A method for preparing the resveratrol lipid nanoparticle suspension according to claim 6, characterized in that, Includes the following steps: S1. Dissolve zinc nitrate hexahydrate and 2-methylimidazole in deionized water, stir at room temperature for 20-30 min, add chitosan, raise the temperature to 45-55℃, stir for 2-4 h, and obtain ZIF-8 / chitosan complex after centrifugation, washing and drying; S2. Dissolve resveratrol in chloroform-methanol solution, add ZIF-8 / chitosan complex, stir at room temperature for 10-15 h, then add complex lipids, cholesterol, ε-polylysine and ascorbate palmitate, evaporate to form a film, then add phosphate buffered saline containing Tween 80, vortex and sonicate in ice bath to obtain a milky white suspension, which is resveratrol lipid nanoparticle suspension.

8. The method for preparing the resveratrol lipid nanoparticle suspension according to claim 7, characterized in that, The composite lipid is a mixture of lecithin, sphingomyelin, and phosphatidylethanolamine-polyethylene glycol 2000-biotin in a mass ratio of 4-6:2-3:

1.

9. The method for preparing the resveratrol lipid nanoparticle suspension according to claim 7, characterized in that, The ultrasonic conditions are as follows: ultrasonic power: 200-240W, ultrasonic time: 5-15min, ultrasonic mode: 10s on / 10s off.

10. The application of the resveratrol lipid nanoparticle suspension according to claim 6 in meat preservation.

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