Bacteriostatic preservative fresh-keeping spray as well as preparation method and application thereof

Abstract

The preparation method comprises the following steps: firstly, taking anthocyanin as a pH response indicator, combining thiamine, pyridoxine and iron ions, compounding lactoferrin to form a compound, adding alginate fibers to prepare microcapsules with pH responsiveness and an antibacterial function, and preparing the antibacterial preservative fresh-keeping spray. The stability of anthocyanin is improved, and color mixing with curcumin is avoided. According to the preparation method, curcumin is taken as a photothermal agent, an antioxidant and a core antibacterial agent, chitosan and alginate fiber are taken as a film-forming agent and an auxiliary antibacterial agent, the microcapsule and an antibacterial main body are mixed, an aqueous solution containing aloe vera gel is added, spray is prepared, and the overall emulsification effect and storage stability of the spray are remarkably improved. The fresh meat preservative is suitable for families, common meat berths, supermarkets and other scenes, can be flexibly sprayed according to requirements, and has high practical value in the fields of fresh meat preservation and preservation and decay early warning.

Description

Technical Field

[0001] This invention belongs to the field of food preservation technology, specifically relating to an antibacterial and preservative spray, its preparation method, and its application. Background Technology

[0002] Fresh meat is an important source of high-quality protein in our daily diet, and its freshness and safety are directly related to consumer health. However, during storage, transportation, and sales, fresh meat is prone to spoilage due to the growth of microorganisms (such as E. coli, Staphylococcus aureus, and Salmonella), enzymatic reactions, and oxidation. This not only results in significant food waste but may also lead to public health problems such as food poisoning. Currently, the industry has developed various technologies to address the preservation and anti-corrosion needs of fresh meat.

[0003] Current fresh meat preservation technologies mostly rely on chemical preservatives (such as nitrites and potassium sorbate) or physical preservation methods (such as low-temperature refrigeration and vacuum packaging). While chemical preservatives can inhibit microbial growth to some extent, long-term excessive use may pose potential health risks, and some preservatives can react with meat components, affecting the meat's flavor and nutritional value. Physical preservation, on the other hand, has the limitation of "passive preservation": low temperatures only slow down the rate of microbial metabolism and cannot completely prevent spoilage. Once the cold chain breaks or the storage time is too long, spoilage will still occur, and there is no way to warn of the spoilage process in advance. Consumers cannot judge the freshness of meat by sight, posing a risk to their consumption. To address the difficulty in detecting fresh meat spoilage, some studies have attempted to introduce pH-responsive indicators (such as anthocyanins and betalains). These indicators utilize amines and organic acids produced by bacterial metabolism during meat spoilage to alter the environmental pH, causing the indicators to change color and providing a visual warning. However, current technologies often involve directly adding or simply mixing these indicators into the preservation system, leading to two major problems: first, the indicators have poor stability and are easily degraded by light, temperature, and the meat's own components, resulting in decreased warning sensitivity; second, if mixed with antibacterial components (such as curcumin and chitosan), the pigments can interact and cause "color mixing," interfering with the identification of warning signals and making it impossible to accurately determine the stage of spoilage. Furthermore, most warning technologies only provide a single "warning" function and are not deeply integrated with preservation functions, making it difficult to form an integrated "preservation-warning" solution. The demand for fresh meat preservation technologies in households, ordinary butcher shops, supermarkets, and markets is characterized by "low cost, ease of operation, and easy accessibility." While existing high-end preservation technologies (such as modified atmosphere packaging and nano-antibacterial coatings) are effective, their high equipment investment and complex operation make them difficult to promote in small and medium-sized settings. Simple preservation methods (such as plastic wrap and ordinary sprays) suffer from short preservation periods and lack of early warning functions, failing to meet consumers' core needs for "identifiable freshness and controllable safety" in fresh meat. With the increasing demand for convenient consumption, antibacterial sprays, due to their flexible use and uniform coverage, are gradually being applied to the field of fresh meat preservation. Summary of the Invention

[0004] The technical problem to be solved: Traditional edible plastic wrap is a wrapping type, which cannot be replenished in time and requires continuous passive preservation. It is only suitable for production preservation in large-scale factories and cannot be conveniently applied in homes, supermarkets, or farmers' markets. Spray form is more flexible than film, applicable to more food types, and is more convenient to use. This invention uses anthocyanins as indicators for responsive microencapsulation, improving their stability while avoiding color mixing with curcumin. The microcapsule particles are then combined with chitosan and curcumin to prepare a spray, improving the overall emulsification effect and stability of the spray. Curcumin is photosensitive and can be excited by light to produce reactive oxygen species, which enhances bactericidal and antibacterial effects.

[0005] Technical solution: A method for preparing an antibacterial, preservative, and freshness-preserving spray, comprising the following steps: S1. Thiamine and pyridoxine are mixed with water and stirred to form a vitamin solution. A metal ion solution is slowly added and stirred in a water bath. Lactoferrin is then added and stirring is continued to form a complex solution. S2. Anthocyanins are dissolved in ethanol solution to form anthocyanin solution, a complex is added and ultrasonically treated, then seaweed fiber is added and homogenized to form microcapsule colostrum, which is then freeze-dried to obtain microcapsule powder. S3. Chitosan is added to an aqueous acetic acid solution, stirred, and the pH is adjusted to obtain a chitosan solution. Curcumin is mixed with glycerol to obtain a curcumin dispersion. S4. Add seaweed fiber to chitosan solution, stir in water bath, slowly add curcumin dispersion, mix and sonicate under light-protected conditions to form antibacterial main solution; S5. Slowly add the antibacterial base solution to the aloe vera gel aqueous solution, stir and mix, add the microcapsule powder, continue stirring, shear emulsify to obtain the spray concentrate, filter and pack into a container to obtain the spray.

[0006] Furthermore, in step S1, the concentration of the vitamin solution is 3-8 wt.%, the stirring speed is 200-300 rpm, the metal ion is zinc ion or iron ion, the water bath stirring temperature is 40-50℃, the water bath stirring speed is 300-500 rpm, and the water bath stirring time is 20-30 min; the stirring speed is continued at 400-600 rpm, and the stirring time is continued at 40-60 min.

[0007] Furthermore, in step S1, the metal ion solution is ferric chloride or zinc sulfate solution, and the concentration of the metal ion solution is 0.01-0.05 mol / L; the mass ratio of thiamine to pyridoxine is (2-4):1, and the mass ratio of vitamin solution, metal ion solution and lactoferrin is 100:(10-30):(3-5).

[0008] Furthermore, in step S2, the concentration of the ethanol solution is 10-30 wt.%, and the anthocyanin content in the anthocyanin solution is 20-50 wt.%; the ultrasonic treatment power is 200-300 W, and the ultrasonic treatment time is 15-20 min; the mass ratio of anthocyanin solution, complex solution, and seaweed fiber is (3-5):50:(1-2); the homogenization speed is 10000-15000 rpm, and the homogenization time is 15-30 min.

[0009] Furthermore, in step S3, the concentration of the acetic acid aqueous solution is 1-2 wt.%; the chitosan concentration of the chitosan solution is 2-4 wt.%; the stirring speed is 400-500 rpm, and the stirring time is 1-1.5 h; the pH is adjusted to 5.5-6.0; and the curcumin content in the curcumin dispersion is 3-5 wt.%.

[0010] Furthermore, in step S4, the mass ratio of chitosan solution, seaweed fiber, and curcumin dispersion is (150-200):(1-3):(50-100); the water bath stirring temperature is 50-60°C, and the water bath stirring time is 40-60 min; the ultrasonic treatment power is 100-200 W, and the time is 10-20 min.

[0011] Furthermore, in step S5, the concentration of the aloe vera gel aqueous solution is 8-12 wt.%; the mass ratio of the antibacterial main solution, the aloe vera gel aqueous solution, and the microcapsule powder is (20-30):(60-75):(3-8); the stirring speed is 200-300 rpm, and the stirring time is 20-40 min; the shear emulsification speed is 8000-10000 rpm, and the time is 10-30 min.

[0012] The above preparation method yields an antibacterial and preservative spray.

[0013] The above-described antibacterial and preservative-preserving spray is used in the preservation of fresh meat.

[0014] Furthermore, after the preservation spray is applied to the surface of fresh meat, the photodynamic effect of curcumin can be activated by shining a mobile phone flashlight or LED light. Beneficial effects

[0015] This invention features an intelligent spoilage indicator, allowing consumers to determine whether food has spoiled without guessing. They can make a judgment based on the visual change in the color of the spray coating (anthocyanins change color under alkaline conditions), greatly improving food safety, reducing health risks caused by accidentally consuming spoiled food, and also reducing food waste caused by the inability to determine spoilage.

[0016] This invention successfully solves two key problems through microencapsulation technology: it improves the chemical stability of anthocyanins, making them less prone to degradation during storage, thus ensuring the durability and reliability of the indicator function; it avoids color interference; and it physically isolates anthocyanins and curcumin, preventing them from mixing when unactivated, which could lead to an overly dark background color or color distortion, thereby ensuring the clarity and accuracy of the color-changing indicator.

[0017] This invention incorporates multiple antibacterial substances, including chitosan, lactoferrin, thiamine / pyridoxine-metal ion complex, and curcumin itself, which has good antibacterial and antioxidant properties, broad-spectrum antibacterial activity, and good inhibitory effects on various bacteria and fungi, resulting in a more comprehensive and longer-lasting preservative effect.

[0018] After spraying, this invention can stimulate curcumin to produce a large amount of reactive oxygen species (ROS) by simply irradiating it with a mobile phone light or a dedicated LED light. This powerfully and rapidly eliminates microorganisms on the coating surface, providing targeted enhancement. When users feel that the risk is high or that additional protection is needed, they can actively increase the antibacterial level by spraying and irradiating. The spray form is more convenient and faster, and is suitable for homes, ordinary butcher shops, supermarkets, and markets.

[0019] The addition of microcapsule particles and chitosan-algae fiber system in this invention significantly improves the emulsification stability of the spray liquid, prevents component separation, and forms a uniform, dense, and strongly adhesive functional protective film on the food surface after spraying. The product has good stability and a long shelf life. The protective film can better isolate air and microorganisms, lock in food moisture, and does not affect the appearance of the food.

[0020] All the core ingredients of this invention (anthocyanins, B vitamins, lactoferrin, chitosan, seaweed fiber, curcumin, and aloe vera gel) are derived from nature, have good biocompatibility and edibility, meet the modern consumer's pursuit of "clean label" products, are highly safe, and do not require concern about the potential health risks of chemical preservatives.

[0021] This invention employs a responsive microcapsule encapsulation indicator with antibacterial function. Bacterial metabolism produces amines or alkaline substances, which can destroy the microcapsules. When the antibacterial substances are unable to exert their effective effect, these substances accumulate and gradually penetrate the microcapsule wall, causing anthocyanins to change color, indicating a change in the acidity or alkalinity of the food and food spoilage.

[0022] This invention utilizes thiamine (vitamin B1) and pyridoxine (vitamin B6), which are pH-responsive and possess antibacterial properties when combined with zinc or iron ions. These are further combined with lactoferrin and seaweed fiber, which also have antibacterial properties. Lactoferrin can also bind with zinc or iron ions, thus forming a complex with thiamine and pyridoxine. When seaweed fiber is added, it forms a stable microcapsule with antibacterial function. Detailed Implementation

[0023] The present invention will be further described below with reference to embodiments. These embodiments are illustrative of the present invention, but the present invention is not limited to these embodiments: Example 1

[0024] A method for preparing an antibacterial, preservative, and freshness-preserving spray includes the following steps: S1.6g thiamine and 2g pyridoxine were mixed with 92g water and stirred at 200 rpm to form an 8wt.% vitamin solution. 30g of 0.03mol / L ferric chloride solution was slowly added and stirred at 500 rpm in a 40℃ water bath for 20min. 3g lactoferrin was added and stirred at 600 rpm for another 40min to form a complex solution. S2.1g of anthocyanin was dissolved in 4g of 10wt.% ethanol solution to form anthocyanin solution. 50g of complex was added and ultrasonically treated at 200W for 20min. Then, 2g of seaweed fiber was added and homogenized at 10000 rpm for 15min to form microcapsule colostrum. The microcapsule powder was obtained by freeze drying. S3. 2g of chitosan was added to 98g of 1wt.% acetic acid aqueous solution, stirred at 500 rpm for 1h, and the pH was adjusted to 6.0 to obtain chitosan solution. 3g of curcumin was added to 97g of glycerol to obtain curcumin dispersion. S4. Add 2g of seaweed fiber to 100g of chitosan solution, stir in a 50°C water bath for 60min, slowly add 25g of curcumin dispersion, mix and sonicate at 300 W for 20min under light-protected conditions to form the antibacterial main solution; Slowly add 70g of 8wt.% aloe vera gel aqueous solution to 30g of antibacterial main solution, stir and mix at 300 rpm for 20min, add 3g of microcapsule powder, continue stirring for 20min, and shear emulsify at 8000 rpm for 15min to obtain spray stock solution, filter and pack into a container to obtain spray. Example 2

[0025] A method for preparing an antibacterial, preservative, and freshness-preserving spray includes the following steps: S1.6g thiamine and 2g pyridoxine were mixed with 92g water and stirred at 200 rpm to form an 8wt.% vitamin solution. 30g of 0.03mol / L ferric chloride solution was slowly added and stirred at 500 rpm in a 40℃ water bath for 20min. 3g lactoferrin was added and stirred at 600 rpm for another 40min to form a complex solution. S2.1g of anthocyanin was dissolved in 4g of 10wt.% ethanol solution to form anthocyanin solution. 50g of complex was added and ultrasonically treated at 200W for 20min. Then, 2g of seaweed fiber was added and homogenized at 10000 rpm for 15min to form microcapsule colostrum. The microcapsule powder was obtained by freeze drying. S3. 2g of chitosan was added to 98g of 1wt.% acetic acid aqueous solution, stirred at 500 rpm for 1h, and the pH was adjusted to 6.0 to obtain chitosan solution. 3g of curcumin was added to 97g of glycerol to obtain curcumin dispersion. Add 0.8g of seaweed fiber to 4.80g of chitosan solution, stir in a 50°C water bath for 60min, slowly add 40g of curcumin dispersion, mix and sonicate at 300 W for 20min under light-protected conditions to form the antibacterial main solution; Slowly add 70g of 8wt.% aloe vera gel aqueous solution to 30g of antibacterial main solution, stir and mix at 300 rpm for 20min, add 3g of microcapsule powder, continue stirring for 20min, and shear emulsify at 8000 rpm for 15min to obtain spray stock solution, filter and pack into a container to obtain spray. Example 3

[0026] A method for preparing an antibacterial, preservative, and freshness-preserving spray includes the following steps: S1.6g thiamine and 2g pyridoxine were mixed with 92g water and stirred at 200 rpm to form an 8wt.% vitamin solution. 30g of 0.03mol / L ferric chloride solution was slowly added and stirred at 500 rpm in a 40℃ water bath for 20min. 3g lactoferrin was added and stirred at 600 rpm for another 40min to form a complex solution. S2.1g of anthocyanin was dissolved in 4g of 10wt.% ethanol solution to form anthocyanin solution. 50g of complex was added and ultrasonically treated at 200W for 20min. Then, 2g of seaweed fiber was added and homogenized at 10000 rpm for 15min to form microcapsule colostrum. The microcapsule powder was obtained by freeze drying. S3. 2g of chitosan was added to 98g of 1wt.% acetic acid aqueous solution, stirred at 500 rpm for 1h, and the pH was adjusted to 6.0 to obtain chitosan solution. 3g of curcumin was added to 97g of glycerol to obtain curcumin dispersion. S4. Add 2g of seaweed fiber to 100g of chitosan solution, stir in a 50°C water bath for 60min, slowly add 25g of curcumin dispersion, mix and sonicate at 300 W for 20min under light-protected conditions to form the antibacterial main solution; Slowly add 70g of 8wt.% aloe vera gel aqueous solution to 20g of antibacterial main solution, stir and mix at 300 rpm for 20min, add 3g of microcapsule powder, continue stirring for 20min, and shear emulsify at 8000 rpm for 15min to obtain spray stock solution, filter and pack into a container to obtain spray. Example 4

[0027] A method for preparing an antibacterial, preservative, and freshness-preserving spray includes the following steps: S1.6g thiamine and 2g pyridoxine were mixed with 92g water and stirred at 200 rpm to form an 8wt.% vitamin solution. 30g of 0.03mol / L ferric chloride solution was slowly added and stirred at 500 rpm in a 40℃ water bath for 20min. 3g lactoferrin was added and stirred at 600 rpm for another 40min to form a complex solution. S2.2g of anthocyanin was dissolved in 8g of 10wt.% ethanol solution to form anthocyanin solution. 100g of complex was added and ultrasonically treated at 200W for 20min. Then, 4g of seaweed fiber was added and homogenized at 10000 rpm for 15min to form microcapsule colostrum. The microcapsule powder was obtained by freeze drying. S3. 2g of chitosan was added to 98g of 1wt.% acetic acid aqueous solution, stirred at 500 rpm for 1h, and the pH was adjusted to 6.0 to obtain chitosan solution. 3g of curcumin was added to 97g of glycerol to obtain curcumin dispersion. S4. Add 2g of seaweed fiber to 100g of chitosan solution, stir in a 50°C water bath for 60min, slowly add 25g of curcumin dispersion, mix and sonicate at 300 W for 20min under light-protected conditions to form the antibacterial main solution; Slowly add 70g of 8wt.% aloe vera gel aqueous solution to 30g of antibacterial main solution, stir and mix at 300 rpm for 20min, add 8g of microcapsule powder, continue stirring for 20min, and shear emulsify at 8000 rpm for 15min to obtain spray stock solution, filter and pack into a container to obtain spray. Example 5

[0028] A method for preparing an antibacterial, preservative, and freshness-preserving spray includes the following steps: S1.6g thiamine and 2g pyridoxine were mixed with 92g water and stirred at 200 rpm to form an 8wt.% vitamin solution. 30g of 0.03mol / L zinc sulfate solution was slowly added and stirred at 500 rpm in a 40℃ water bath for 20min. 3g lactoferrin was added and stirred at 600 rpm for another 40min to form a complex solution. S2.1g of anthocyanin was dissolved in 4g of 10wt.% ethanol solution to form anthocyanin solution. 50g of complex was added and ultrasonically treated at 200W for 20min. Then, 2g of seaweed fiber was added and homogenized at 10000 rpm for 15min to form microcapsule colostrum. The microcapsule powder was obtained by freeze drying. S3. 2g of chitosan was added to 98g of 1wt.% acetic acid aqueous solution, stirred at 500 rpm for 1h, and the pH was adjusted to 6.0 to obtain chitosan solution. 3g of curcumin was added to 97g of glycerol to obtain curcumin dispersion. S4. Add 2g of seaweed fiber to 100g of chitosan solution, stir in a 50°C water bath for 60min, slowly add 25g of curcumin dispersion, mix and sonicate at 300 W for 20min under light-protected conditions to form the antibacterial main solution; Slowly add 70g of 8wt.% aloe vera gel aqueous solution to 30g of antibacterial main solution, stir and mix at 300 rpm for 20min, add 3g of microcapsule powder, continue stirring for 20min, and shear emulsify at 8000 rpm for 15min to obtain spray stock solution, filter and pack into a container to obtain spray. Example 6

[0029] A method for preparing an antibacterial, preservative, and freshness-preserving spray includes the following steps: S1.6g thiamine and 2g pyridoxine were mixed with 92g water and stirred at 200 rpm to form an 8wt.% vitamin solution. 30g of 0.03mol / L ferric chloride solution was slowly added and stirred at 500 rpm in a 40℃ water bath for 20min. 5g lactoferrin was added and stirred at 600 rpm for another 40min to form a complex solution. S2.1g of anthocyanin was dissolved in 4g of 10wt.% ethanol solution to form anthocyanin solution. 50g of complex was added and ultrasonically treated at 200W for 20min. Then, 2g of seaweed fiber was added and homogenized at 10000 rpm for 15min to form microcapsule colostrum. The microcapsule powder was obtained by freeze drying. S3. 2g of chitosan was added to 98g of 1wt.% acetic acid aqueous solution, stirred at 500 rpm for 1h, and the pH was adjusted to 6.0 to obtain chitosan solution. 3g of curcumin was added to 97g of glycerol to obtain curcumin dispersion. S4. Add 2g of seaweed fiber to 100g of chitosan solution, stir in a 50°C water bath for 60min, slowly add 25g of curcumin dispersion, mix and sonicate at 300 W for 20min under light-protected conditions to form the antibacterial main solution; Slowly add 70g of 8wt.% aloe vera gel aqueous solution to 30g of antibacterial main solution, stir and mix at 300 rpm for 20min, add 3g of microcapsule powder, continue stirring for 20min, and shear emulsify at 8000 rpm for 15min to obtain spray stock solution, filter and pack into a container to obtain spray. Comparative Example 1

[0030] The difference between this comparative example and Example 1 is that thiamine and pyridoxine were not added in the preparation of the responsive microcapsules, as detailed below: S1.3g lactoferrin was added to 97g water and stirred at 600 rpm for 40 minutes to form a lactoferrin solution; S2.1g of anthocyanin was dissolved in 4g of 10wt.% ethanol solution to form anthocyanin solution. 50g of lactoferrin solution was added and ultrasonicated at 200W for 20min. Then, 2g of seaweed fiber was added and homogenized at 10000 rpm for 15min to form microcapsule colostrum. The microcapsule powder was obtained by freeze drying. S3. 2g of chitosan was added to 98g of 1wt.% acetic acid aqueous solution, stirred at 500 rpm for 1h, and the pH was adjusted to 6.0 to obtain chitosan solution. 3g of curcumin was added to 97g of glycerol to obtain curcumin dispersion. S4. Add 2g of seaweed fiber to 100g of chitosan solution, stir in a 50°C water bath for 60min, slowly add 25g of curcumin dispersion, mix and sonicate at 300 W for 20min under light-protected conditions to form the antibacterial main solution; Slowly add 70g of 8wt.% aloe vera gel aqueous solution to 30g of antibacterial main solution, stir and mix at 300 rpm for 20min, add 3g of microcapsule powder, continue stirring for 20min, and shear emulsify at 8000 rpm for 15min to obtain spray stock solution, filter and pack into a container to obtain spray. Comparative Example 2

[0031] The difference between this comparative example and Example 1 is that no metal ions are added, as detailed below: S1.6g thiamine and 2g pyridoxine were mixed with 92g water and stirred at 200 rpm to form an 8wt.% vitamin solution. 3g lactoferrin was added and stirred at 600 rpm for 40 minutes to form a complex solution. S2.1g of anthocyanin was dissolved in 4g of 10wt.% ethanol solution to form anthocyanin solution. 50g of complex was added and ultrasonically treated at 200W for 20min. Then, 2g of seaweed fiber was added and homogenized at 10000 rpm for 15min to form microcapsule colostrum. The microcapsule powder was obtained by freeze drying. S3. 2g of chitosan was added to 98g of 1wt.% acetic acid aqueous solution, stirred at 500 rpm for 1h, and the pH was adjusted to 6.0 to obtain chitosan solution. 3g of curcumin was added to 97g of glycerol to obtain curcumin dispersion. S4. Add 2g of seaweed fiber to 100g of chitosan solution, stir in a 50°C water bath for 60min, slowly add 25g of curcumin dispersion, mix and sonicate at 300 W for 20min under light-protected conditions to form the antibacterial main solution; Slowly add 70g of 8wt.% aloe vera gel aqueous solution to 30g of antibacterial main solution, stir and mix at 300 rpm for 20min, add 3g of microcapsule powder, continue stirring for 20min, and shear emulsify at 8000 rpm for 15min to obtain spray stock solution, filter and pack into a container to obtain spray. Comparative Example 3

[0032] The difference between this comparative example and Example 2 is that seaweed fiber is not added to the microcapsules, as detailed below: S1.6g thiamine and 2g pyridoxine were mixed with 92g water and stirred at 200 rpm to form an 8wt.% vitamin solution. 30g of 0.03mol / L ferric chloride solution was slowly added and stirred at 500 rpm in a 40℃ water bath for 20min. 3g lactoferrin was added and stirred at 600 rpm for another 40min to form a complex solution. S2.1g of anthocyanin was dissolved in 4g of 10wt.% ethanol solution to form anthocyanin solution. 50g of complex was added and ultrasonicated at 200W for 20min. The mixture was homogenized at 10000 rpm for 15min to form microcapsule colostrum. The microcapsule powder was obtained by freeze drying. S3. 2g of chitosan was added to 98g of 1wt.% acetic acid aqueous solution, stirred at 500 rpm for 1h, and the pH was adjusted to 6.0 to obtain chitosan solution. 3g of curcumin was added to 97g of glycerol to obtain curcumin dispersion. S4. Add 2g of seaweed fiber to 100g of chitosan solution, stir in a 50°C water bath for 60min, slowly add 25g of curcumin dispersion, mix and sonicate at 300 W for 20min under light-protected conditions to form the antibacterial main solution; Slowly add 70g of 8wt.% aloe vera gel aqueous solution to 30g of antibacterial main solution, stir and mix at 300 rpm for 20min, add 3g of microcapsule powder, continue stirring for 20min, and shear emulsify at 8000 rpm for 15min to obtain spray stock solution, filter and pack into a container to obtain spray. Comparative Example 4

[0033] The difference between this comparative example and Example 2 is that seaweed fiber is not added to the antibacterial main solution, as detailed below: S1.6g thiamine and 2g pyridoxine were mixed with 92g water and stirred at 200 rpm to form an 8wt.% vitamin solution. 30g of 0.03mol / L ferric chloride solution was slowly added and stirred at 500 rpm in a 40℃ water bath for 20min. 3g lactoferrin was added and stirred at 600 rpm for another 40min to form a complex solution. S2.1g of anthocyanin was dissolved in 4g of 10wt.% ethanol solution to form anthocyanin solution. 50g of complex was added and ultrasonically treated at 200W for 20min. Then, 2g of seaweed fiber was added and homogenized at 10000 rpm for 15min to form microcapsule colostrum. The microcapsule powder was obtained by freeze drying. S3. 2g of chitosan was added to 98g of 1wt.% acetic acid aqueous solution, stirred at 500 rpm for 1h, and the pH was adjusted to 6.0 to obtain chitosan solution. 3g of curcumin was added to 97g of glycerol to obtain curcumin dispersion. S4. Slowly add 25g curcumin dispersion to 100g chitosan solution, mix and sonicate at 300 W for 20min under light-protected conditions to form antibacterial main solution; Slowly add 70g of 8wt.% aloe vera gel aqueous solution to 30g of antibacterial main solution, stir and mix at 300 rpm for 20min, add 3g of microcapsule powder, continue stirring for 20min, and shear emulsify at 8000 rpm for 15min to obtain spray stock solution, filter and pack into a container to obtain spray. Comparative Example 5

[0034] The difference between this comparative example and Example 1 is that aloe vera gel is not added, as detailed below: S1.6g thiamine and 2g pyridoxine were mixed with 92g water and stirred at 200 rpm to form an 8wt.% vitamin solution. 30g of 0.03mol / L ferric chloride solution was slowly added and stirred at 500 rpm in a 40℃ water bath for 20min. 3g lactoferrin was added and stirred at 600 rpm for another 40min to form a complex solution. S2.1g of anthocyanin was dissolved in 4g of 10wt.% ethanol solution to form anthocyanin solution. 50g of complex was added and ultrasonically treated at 200W for 20min. Then, 2g of seaweed fiber was added and homogenized at 10000 rpm for 15min to form microcapsule colostrum. The microcapsule powder was obtained by freeze drying. S3. 2g of chitosan was added to 98g of 1wt.% acetic acid aqueous solution, stirred at 500 rpm for 1h, and the pH was adjusted to 6.0 to obtain chitosan solution. 3g of curcumin was added to 97g of glycerol to obtain curcumin dispersion. S4. Add 2g of seaweed fiber to 100g of chitosan solution, stir in a 50°C water bath for 60min, slowly add 25g of curcumin dispersion, mix and sonicate at 300 W for 20min under light-protected conditions to form the antibacterial main solution; Slowly add 70g of water to 30g of antibacterial main solution, stir and mix at 300 rpm for 10 minutes, add 3g of microcapsule powder, continue stirring for 20 minutes, and shear emulsify at 8000 rpm for 15 minutes to obtain the spray stock solution, filter and pack into a container to obtain the spray. Performance testing

[0035] Stability test The particle size of the diluted samples was measured using a particle size analyzer. The samples were then stored for 5 days, 10 days, 15 days, and 20 days, and the particle size was measured at each time.

[0036] The results are shown in Table 1, influenced by component ratios, additives (such as seaweed fiber and aloe vera gel), and metal ion crosslinking. The examples with complete components and optimized ratios had smaller initial particle sizes (less than 4 μm), while the comparative examples had larger initial particle sizes. The particle size growth rate during storage depended on the stability of the formulation. Examples with added stabilizers (such as seaweed fiber and aloe vera gel) and metal ions showed slower particle size growth, while the comparative examples lacking key components showed faster particle size growth. Example 4, due to the doubled amount of microcapsule components, resulted in a larger initial particle size, but its stability was similar to Example 1, with a similar particle size growth rate. Comparative Example 1, lacking thiamine and pyridoxine, had an unstable microcapsule structure, large particle size, rapid aggregation during storage, and rapid particle size growth. Comparative Example 2, lacking metal ions, had insufficient crosslinking, leading to easy aggregation of microcapsules, large initial particle size, and rapid growth. Comparative Example 3, lacking seaweed fiber in its microcapsules, had a fragile structure and the fastest particle size growth during storage. Comparative Example 4, lacking seaweed fiber in its antibacterial matrix, had poor film-forming properties and an unstable emulsion. Comparative Example 5, lacking aloe vera gel, had an emulsion that lacked stabilizers, making it prone to separation and aggregation. Table 1. Particle size of the spray (μm)

[0037]

[0038] Antibacterial test The agar perforation diffusion method was used. Bacterial suspension was added to an agar plate in a petri dish, spread evenly with a spreader, and perforated with a perforator. 100 μl of spray agent, a positive control, and a negative control were added to each perforator. After incubation at 37°C for at least 12 h, the diameter of the inhibition zone was visually observed and measured.

[0039] The specific results are shown in Table 2. The antibacterial effect of the examples was significantly better than that of the comparative examples. Comparative example 2 lacked metal ions, which hindered the formation of the complex. Furthermore, the lack of metal ion complexation reduced the antibacterial effects of thiamine, pyridoxine, and lactoferrin. Comparative example 5 lacked aloe vera gel, thus lacking synergistic antibacterial activity.

[0040] Table 2. Diameter of the antibacterial zone of the spray.

[0041] Protect antioxidant properties DPPH free radical scavenging rate determination Prepare 1.75×10 with ethanol -4 Prepare a 2 mL solution of DPPH solution (mol / L), dilute to a specific concentration, dissolve the analyte in the DPPH solution, mix thoroughly, and let stand for 30 min. Measure the absorbance at 517 nm.

[0042] DPPH free radical scavenging rate (%) =

[0043] In the formula: A i The absorbance of 2 mL of DPPH solution and 2 mL of sample solution; A j The absorbance of 2 mL of sample extract and 2 mL of ethanol; A c The absorbance is the result of mixing 2 mL of DPPH solution with 2 mL of ethanol.

[0044] Determination of ABTS free radical scavenging rate Take 1 mL of sample solution diluted to a certain concentration, add 3 mL of ABTS+ solution (7 mM ABTS solution and 2.45 mM K2S2O2 are mixed in equal proportions and reacted overnight (12 h-16 h) to prepare ABTS·+ stock solution. Adjust the absorbance of the ABTS·+ reaction solution at 734 nm to 0.70 ± 0.02;), shake for 30 s, react at room temperature in the dark for 60 min, and then measure the absorbance value at 734 nm.

[0045] ABTS · + Clearance Rate (%) = (Acontrol − Atest) ∗100 / Acontrol In the formula: Acontrol is the absorbance value of the control tube; Atest is the absorbance value of the sample to be tested.

[0046] The results are shown in Table 3. The antioxidant properties of all comparative examples were lower than those of the examples. Examples 2 and 4 exhibited the highest free radical scavenging rates. Example 2 improved the stability and efficiency of the active ingredient by optimizing the film-forming agent ratio; Example 4 achieved synergistic enhancement by increasing the amount of antioxidant (anthocyanin). A comparison of Examples 1 and 3 clearly shows that reducing the amount of the antibacterial component (i.e., curcumin) directly leads to a significant decrease in antioxidant capacity. Example 5 used zinc ions instead of iron ions, and its antioxidant performance was comparable to the baseline group, indicating that this substitution is technically feasible and provides flexibility for formulation adjustments.

[0047] Table 3 Free radical scavenging rate

[0048] Preservation Experiment The spray was applied to fresh pork, and the timing began immediately. After 12 hours, the pork was sprayed again and exposed to light. The time required for the indicator to develop color (turning blue, green, or yellow) was recorded. Observations and samples were taken every 12 hours. The accuracy and reasonableness of the indicator display were determined based on the measured volatile basic nitrogen (TVB-N).

[0049] As shown in Table 4, the TVB-N value of Example 1 exceeded 15 mg / 100g after 96 hours, and the indicator changed color significantly, indicating a good antibacterial effect and good preservation of pork freshness. In Comparative Example 1, due to the absence of thiamine and pyridoxine, the capsules were destroyed more rapidly, leading to indicator color change. Comparative Example 2, lacking metal ions, experienced hindered complex formation, resulting in poor antibacterial effect and poor capsule stability. The pork freshness of the comparative examples decreased significantly faster than that of Example 1, demonstrating the significant preservation effect of the examples on pork.

[0050] Table 4 Results of the preservation experiment

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall still fall within the scope of protection of the present invention.

Claims

1. A method for preparing an antibacterial, preservative, and freshness-preserving spray, characterized in that, Includes the following steps: S1. Thiamine and pyridoxine are mixed with water and stirred to form a vitamin solution. A metal ion solution is slowly added and stirred in a water bath. Lactoferrin is then added and stirring is continued to form a complex solution. S2. Anthocyanins are dissolved in ethanol solution to form anthocyanin solution, a complex is added and ultrasonically treated, then seaweed fiber is added and homogenized to form microcapsule colostrum, which is then freeze-dried to obtain microcapsule powder. S3. Chitosan is added to an aqueous acetic acid solution, stirred, and the pH is adjusted to obtain a chitosan solution. Curcumin is mixed with glycerol to obtain a curcumin dispersion. S4. Add seaweed fiber to chitosan solution, stir in water bath, slowly add curcumin dispersion, mix and sonicate under light-protected conditions to form antibacterial main solution; S5. Slowly add the antibacterial base solution to the aloe vera gel aqueous solution, stir and mix, add the microcapsule powder, continue stirring, shear emulsify to obtain the spray concentrate, filter and pack into a container to obtain the spray.

2. The preparation method of the antibacterial, preservative and fresh-keeping spray according to claim 1, characterized in that: In step S1, the concentration of the vitamin solution is 3-8 wt.%, the stirring speed is 200-300 rpm, the metal ions are zinc ions or iron ions, the water bath stirring temperature is 40-50℃, the water bath stirring speed is 300-500 rpm, and the water bath stirring time is 20-30 min; the stirring speed is continued at 400-600 rpm, and the stirring time is continued at 40-60 min.

3. The method for preparing an antibacterial, preservative, and fresh-keeping spray according to claim 1, characterized in that: In step S1, the metal ion solution is either ferric chloride or zinc sulfate solution, and the concentration of the metal ion solution is 0.01-0.05 mol / L; the mass ratio of thiamine to pyridoxine is (2-4):1, and the mass ratio of vitamin solution, metal ion solution and lactoferrin is 100:(10-30):(3-5).

4. The method for preparing an antibacterial, preservative, and fresh-keeping spray according to claim 1, characterized in that: In step S2, the concentration of the ethanol solution is 10-30 wt.%, and the anthocyanin content in the anthocyanin solution is 20-50 wt.%; the ultrasonic treatment power is 200-300 W, and the ultrasonic treatment time is 15-20 min; the mass ratio of anthocyanin solution, complex solution and seaweed fiber is (3-5):50:(1-2); the homogenization speed is 10000-15000 rpm, and the homogenization time is 15-30 min.

5. The method for preparing an antibacterial, preservative, and fresh-keeping spray according to claim 1, characterized in that: In step S3, the concentration of the acetic acid aqueous solution is 1-2 wt.%; the chitosan concentration of the chitosan solution is 2-4 wt.%; the stirring speed is 400-500 rpm, and the stirring time is 1-1.5 h; the pH is adjusted to 5.5-6.0; and the curcumin content in the curcumin dispersion is 3-5 wt.%.

6. The method for preparing an antibacterial, preservative, and fresh-keeping spray according to claim 1, characterized in that: In step S4, the mass ratio of chitosan solution, seaweed fiber and curcumin dispersion is (150-200):(1-3):(50-100); the water bath stirring temperature is 50-60°C and the water bath stirring time is 40-60 min; the ultrasonic treatment power is 100-200 W and the time is 10-20 min.

7. The method for preparing an antibacterial, preservative, and fresh-keeping spray according to claim 1, characterized in that: In step S5, the concentration of the aloe vera gel aqueous solution is 8-12 wt.%; the mass ratio of the antibacterial main solution, the aloe vera gel aqueous solution, and the microcapsule powder is (20-30):(60-75):(3-8); the stirring speed is 200-300 rpm, and the stirring time is 20-40 min; the shear emulsification speed is 8000-10000 rpm, and the time is 10-30 min.

8. A preservative spray with antibacterial and antiseptic properties obtained by the preparation method according to any one of claims 1-7.

9. The application of the antibacterial and preservative spray according to claim 8 in the preservation of fresh meat.

10. The application of the antibacterial and preservative spray according to claim 9 in the preservation of fresh meat, characterized in that: After the preservation spray is applied to the surface of fresh meat, the photodynamic effect of curcumin can be activated by shining a mobile phone flashlight or LED light.

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