Glucomannan-water-soluble cellulose antibacterial material, preparation method thereof and preservative film

Abstract

The invention relates to the technical field of fresh-keeping materials, in particular to a glucomannan-water-soluble cellulose antibacterial material, a preparation method thereof and a fresh-keeping film. The preparation method comprises the following steps: preparing an aqueous phase solution from glucomannan with a mass concentration of 1.5-3.5% and water-soluble cellulose with a mass concentration of 1.0-2.5%; preparing an oil phase solution by using an antibacterial agent and an emulsifier; dropwise adding the oil-phase solution into the water-phase solution, and carrying out high-speed shearing emulsification to form a nano-emulsion; adding a cross-linking agent into the nano-emulsion to form a cross-linked emulsion with a net structure; and preparing the cross-linked emulsion into the sustained-release capsule. According to the preparation method, the antibacterial agent is effectively wrapped by a mixed system of glucomannan and water-soluble cellulose, and the antibacterial agent can be stably released.

Description

Technical Field

[0001] The invention relates to the technical field of fresh-keeping materials, and in particular to a glucomannan-water-soluble cellulose antibacterial material and a preparation method thereof and a fresh-keeping film. Background Art

[0002] Food preservation methods usually include refrigeration, freezing, or vacuum packaging; although these methods can extend the shelf life of food to a certain extent, the effect is limited and food spoilage is still likely to occur.

[0003] Related Technology In order to further extend the shelf life of food, natural plant essential oils with good antibacterial and antioxidant properties are also used in food preservation.

[0004] However, this type of natural plant essential oil antibacterial agent is volatile and unstable, making it difficult to use it directly in food preservation and storage. Summary of the invention

[0005] The purpose of the present invention is to provide a glucomannan-water-soluble cellulose antibacterial material, a preparation method thereof and a preservative film. The preparation method utilizes a mixed system of glucomannan and water-soluble cellulose to effectively encapsulate an antibacterial agent and ensure that the antibacterial agent can be stably released, thereby improving and prolonging the antibacterial effect of the glucomannan-water-soluble cellulose antibacterial material. Moreover, both glucomannan and water-soluble cellulose are biocompatible materials, thereby ensuring the safety of the glucomannan-water-soluble cellulose antibacterial material. The preservative film prepared from the glucomannan-water-soluble cellulose antibacterial material can be used for preserving food.

[0006] The present invention is achieved in that:

[0007] In a first aspect, the present invention provides a method for preparing a glucomannan-water-soluble cellulose antibacterial material, comprising:

[0008] Prepare an aqueous phase solution using glucomannan and water-soluble cellulose, wherein the mass concentration of glucomannan is 1.5-3.5%, and the mass concentration of water-soluble cellulose is 1.0-2.5%;

[0009] preparing an oil phase solution with an antimicrobial agent and an emulsifier;

[0010] The oil phase solution is added dropwise to the water phase solution, and high-speed shear emulsification is performed to form a nanoemulsion;

[0011] adding a cross-linking agent to the nanoemulsion to form a cross-linked emulsion having a network structure;

[0012] The cross-linked latex was prepared into sustained-release capsules.

[0013] In an optional embodiment, the mass concentration of glucomannan is 2.5%, and the mass concentration of water-soluble cellulose is 1.5%.

[0014] In an alternative embodiment, the water-soluble cellulose includes at least one of hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose and polymerized quaternium-10.

[0015] In an alternative embodiment, the emulsifier comprises Tween 80, and the cross-linking agent comprises at least one of a calcium chloride solution and glutaraldehyde.

[0016] In an alternative embodiment, the antimicrobial agent comprises at least one of eugenol, carvacrol, thymol, citral, cinnamaldehyde, vanillin, perillaldehyde, citronellol, cumin essential oil and benzyl isothiocyanate.

[0017] In an optional embodiment, the method of adding a cross-linking agent to the nanoemulsion comprises: dropping the cross-linking agent into the nanoemulsion, stirring, and reacting at a temperature of 35-45°C.

[0018] In an optional embodiment, the method of preparing the cross-linked emulsion into a sustained-release capsule comprises: spray-drying the cross-linked emulsion.

[0019] In an optional embodiment, the inlet temperature of the spray drying is 170-190° C., the outlet temperature is 80-90° C., the atomization pressure is 0.15-0.25 MPa, and the feed rate is 4-6 mL / min.

[0020] In an optional embodiment, the rotation speed of the high-speed shear emulsification is 10000-15000 rpm.

[0021] In a second aspect, the present invention provides a glucomannan-water-soluble cellulose antibacterial material, which is prepared by the method for preparing a glucomannan-water-soluble cellulose antibacterial material according to any one of the aforementioned embodiments.

[0022] In a third aspect, the present invention provides a fresh-keeping film, the raw materials for preparing the fresh-keeping film include resin and the aforementioned glucomannan-water-soluble cellulose antibacterial material.

[0023] The beneficial effects of the preparation method of the glucomannan-water-soluble cellulose antibacterial material of the present invention include: the preparation method of the glucomannan-water-soluble cellulose antibacterial material provided by the embodiment of the present invention optimizes the ratio of glucomannan and water-soluble cellulose, can effectively encapsulate the antibacterial agent, and ensure that the antibacterial agent can be stably released, that is, the antibacterial effect of the glucomannan-water-soluble cellulose antibacterial material is improved and prolonged. Moreover, both glucomannan and water-soluble cellulose are biocompatible materials, ensuring the safety of the glucomannan-water-soluble cellulose antibacterial material.

[0024] The beneficial effects of the glucomannan-water-soluble cellulose antibacterial material of the present invention include: the glucomannan-water-soluble cellulose antibacterial material provided by the embodiment of the present invention utilizes glucomannan and water-soluble cellulose with optimized ratios to improve the encapsulation effect of the antibacterial agent and ensure the stable release of the antibacterial components in the glucomannan-water-soluble cellulose antibacterial material; moreover, the glucomannan-water-soluble cellulose antibacterial material has good safety and can be used in the fields of food preservation and the like.

[0025] The beneficial effects of the cling film of the present invention include: the raw materials for preparing the cling film provided by the embodiment of the present invention include resin and the aforementioned glucomannan-water-soluble cellulose antibacterial material, and the glucomannan-water-soluble cellulose antibacterial material is used to achieve long-term sustained release of the antibacterial agent, so that the cling film has a long-term antibacterial and fresh-keeping effect. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0027] The present invention provides a method for preparing a glucomannan-water-soluble cellulose antibacterial material, comprising: preparing an aqueous phase solution using glucomannan and water-soluble cellulose, wherein the mass concentration of glucomannan in the aqueous phase solution is 1.5-3.5% (for example: 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, etc., which are not specifically limited herein), and the mass concentration of water-soluble cellulose in the aqueous phase solution is 1.0-2.5% (for example: 1.0%, 1.5%, 2.0%, 2.5%, etc., which are not specifically limited herein); preparing an oil phase solution using an antibacterial agent and an emulsifier; dropping the oil phase solution into the aqueous phase solution, and performing high-speed shear emulsification to form a nanoemulsion; adding a crosslinking agent to the nanoemulsion to form a crosslinked emulsion with a network structure; and preparing the crosslinked emulsion into a sustained-release capsule.

[0028] Optimizing the ratio of glucomannan and water-soluble cellulose can effectively encapsulate the antibacterial agent and ensure that the antibacterial agent can be stably released, thereby improving and prolonging the antibacterial effect of the glucomannan-water-soluble cellulose antibacterial material. Moreover, both glucomannan and water-soluble cellulose are biocompatible materials, which ensures the safety of the glucomannan-water-soluble cellulose antibacterial material, so that the glucomannan-water-soluble cellulose antibacterial material has good safety and can be used in the field of food preservation.

[0029] Optionally, the mass concentration of glucomannan is 2.5%, and the mass concentration of water-soluble cellulose is 1.5%. Optimizing the ratio of glucomannan to water-soluble cellulose can further improve the encapsulation rate of the antibacterial agent, so that the encapsulation rate of the antibacterial agent can reach 85% or more, and can achieve long-term sustained release.

[0030] Optionally, the glucomannan may be derived from konjac, locust bean gum, tara gum, etc., which are not specifically limited herein.

[0031] Optionally, the water-soluble cellulose includes at least one of hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose and polyquaternium-10. The above water-soluble celluloses all have good biocompatibility and are used to prepare the glucomannan-water-soluble cellulose antibacterial material, which can ensure the safety of the glucomannan-water-soluble cellulose antibacterial material.

[0032] Optionally, the emulsifier comprises Tween 80; and the cross-linking agent comprises at least one of a calcium chloride solution and glutaraldehyde.

[0033] It should be noted that the concentrations of the emulsifier, calcium chloride solution and glutaraldehyde can be selected as needed, for example: the mass concentration of the emulsifier can be 0.5-2%, the mass concentration of the calcium chloride solution can be 4-6%, and the final volume percentage of glutaraldehyde in the cross-linked emulsion can be 0.5-2%, which is not specifically limited here.

[0034] Optionally, the antibacterial agent includes at least one of eugenol, carvacrol, thymol, citral, cinnamaldehyde, vanillin, perillaldehyde, citronellol, cumin essential oil and benzyl isothiocyanate. The above antibacterial agents are all plant antibacterial essential oils, which not only have good antibacterial and antioxidant capabilities, but also have sufficiently high safety. Moreover, the plant antibacterial essential oils are volatile and can be effectively volatilized to improve the food preservation effect.

[0035] Optionally, the mass concentration of the antibacterial agent in the oil phase solution may be 3-7%, for example: 3%, 4%, 5%, 6%, 7%, etc., which is not specifically limited here.

[0036] Optionally, the method of adding a crosslinking agent to the nanoemulsion includes: dropping the crosslinking agent into the nanoemulsion, stirring, and reacting at a temperature of 35-45° C., for example, 35° C., 38° C., 40° C., 42° C., and 45° C. Optimizing the temperature of the crosslinking reaction can ensure the stability and mechanical strength of the formed network structure, improve the encapsulation rate of the antibacterial agent, and ensure that the encapsulated antibacterial agent can be stably released.

[0037] Optionally, the method of preparing the cross-linked emulsion into sustained-release capsules includes: spray drying the cross-linked emulsion. The method of preparing capsules by spray drying is simple and easy to operate, and is convenient for mass production.

[0038] Furthermore, the inlet temperature of spray drying is 170-190°C (for example: 170°C, 175°C, 180°C, 185°C, 190°C, etc., not specifically limited herein), the outlet temperature is 80-90°C (for example: 80°C, 82°C, 85°C, 88°C, 90°C, etc., not specifically limited herein), the atomization pressure is 0.15-0.25MPa (for example: 0.15MPa, 0.18MPa, 0.20MPa, 0.25MPa, etc., not specifically limited herein), and the feed rate is 4-6mL / min (for example: 4mL / min, 5mL / min, 6mL / min, etc., not specifically limited herein).

[0039] It should be noted that after the sustained-release capsules are prepared by spray drying, they can be screened to select particles of corresponding particle sizes and then vacuum-packed separately.

[0040] Optionally, the rotation speed of the high-speed shear emulsification is 10000-15000 rpm, for example: 10000 rpm, 12000 rpm, 15000 rpm, etc., which is not specifically limited here.

[0041] The present disclosure also provides a fresh-keeping film, the raw materials of which include resin and the glucomannan-water-soluble cellulose antibacterial material prepared by the above-mentioned preparation method, wherein the resin includes but is not limited to polyethylene (PE), polylactic acid (PLA), and polyvinylidene chloride (PVDC).

[0042] Optionally, the method for preparing the cling film comprises mixing the resin and the glucomannan-water-soluble cellulose antibacterial material, and then extruding the mixture using a twin-screw extruder to form a film.

[0043] Optionally, the mass percentage of the glucomannan-water-soluble cellulose antibacterial material in the plastic wrap is 1-5%, for example: 1%, 2%, 3%, 4%, 5%, etc., which is not specifically limited here.

[0044] The present invention is further described in detail below in conjunction with embodiments.

[0045] Example 1

[0046] Prepare raw materials and equipment; raw materials: konjac glucomannan (food grade, viscosity ≥30000 mPa·s), hydroxypropyl cellulose (food grade, viscosity 100-300 mPa·s), carvacrol essential oil, deionized water, Tween 80 (food grade), glutaraldehyde (analytical grade, used as a cross-linking agent); equipment: high-speed shear emulsifier, constant temperature magnetic stirrer, spray dryer, vacuum packaging machine.

[0047] 1. Preparation of aqueous phase: Slowly add konjac glucomannan and hydroxypropyl cellulose to deionized water and stir at 60° C. for 2 hours until they are completely dissolved to obtain a transparent and viscous aqueous phase solution, wherein the mass concentration of glucomannan is 2.5% and the mass concentration of cellulose is 1.5%.

[0048] 2. Preparation of oil phase: Add Tween 80 to carvacrol essential oil; stir at room temperature for 10 minutes to obtain a uniform oil phase solution, wherein the mass concentration of carvacrol essential oil is 5%.

[0049] 3. Emulsification: slowly drop the oil phase solution into the water phase solution and use a high-speed shear emulsifier for emulsification; emulsification conditions: rotation speed 12000 rpm, time 15 minutes; after emulsification, a milky white translucent nanoemulsion is obtained.

[0050] 4. Cross-linking: slowly add glutaraldehyde solution to the emulsion until the volume percentage of glutaraldehyde reaches 0.5%, and stir evenly; react at 40° C. for 2 hours to form a cross-linked emulsion with a network structure.

[0051] 5. Spray drying: transfer the cross-linked emulsion to a spray dryer for drying; spray drying conditions: inlet temperature 180°C, outlet temperature 85°C, atomization pressure 0.2MPa, feed rate 5mL / min; collect the dried powder.

[0052] 6. Screening and packaging: Use a 100-mesh sieve to screen the dried powder; vacuum pack the screened powder and store it away from light.

[0053] Example 2

[0054] 1. Preparation of aqueous phase: slowly add glucomannan and carboxymethyl cellulose into deionized water, stir at 60°C for 2 hours until completely dissolved to obtain a transparent and viscous aqueous phase solution, wherein the mass concentration of glucomannan is 1.5% and the mass concentration of cellulose is 1.0%.

[0055] 2. Preparation of oil phase: Add cinnamaldehyde to Tween 80; stir at room temperature for 10 minutes to obtain a uniform oil phase solution, wherein the mass concentration of cinnamaldehyde is 3%.

[0056] 3. Emulsification: slowly drop the oil phase solution into the water phase solution and use a high-speed shear emulsifier for emulsification; emulsification conditions: rotation speed 10000 rpm, time 15 minutes; after emulsification, a milky white translucent nanoemulsion is obtained.

[0057] 4. Cross-linking: slowly add glutaraldehyde solution to the emulsion until the volume percentage of glutaraldehyde reaches 0.3%, and stir evenly; react at 35° C. for 2 hours to form a cross-linked emulsion with a network structure.

[0058] 5. Spray drying: transfer the cross-linked emulsion to a spray dryer for drying; spray drying conditions: inlet temperature 170°C, outlet temperature 80°C, atomization pressure 0.15 MPa, feed rate 4 mL / min; collect the dried powder.

[0059] 6. Screening and packaging: Use a 100-mesh sieve to screen the dried powder; vacuum pack the screened powder and store it away from light.

[0060] Example 3

[0061] 1. Preparation of aqueous phase: slowly add glucomannan and hydroxyethyl cellulose into deionized water, stir at 60°C for 2 hours until completely dissolved to obtain a transparent and viscous aqueous phase solution, wherein the mass concentration of glucomannan is 3.5% and the mass concentration of cellulose is 2.5%.

[0062] 2. Preparation of oil phase: Add eugenol to Tween 80; stir at room temperature for 10 minutes to obtain a uniform oil phase solution, wherein the mass concentration of eugenol essential oil is 7%.

[0063] 3. Emulsification: slowly drop the oil phase solution into the water phase solution and use a high-speed shear emulsifier for emulsification; emulsification conditions: rotation speed 15000 rpm, time 15 minutes; after emulsification, a milky white translucent nanoemulsion is obtained.

[0064] 4. Cross-linking: slowly add glutaraldehyde solution to the emulsion until the volume percentage of glutaraldehyde reaches 0.5%, and stir evenly; react at 45° C. for 2 hours to form a cross-linked emulsion with a network structure.

[0065] 5. Spray drying: transfer the cross-linked emulsion to a spray dryer for drying; spray drying conditions: inlet temperature 190°C, outlet temperature 90°C, atomization pressure 0.25 MPa, feed rate 6 mL / min; collect the dried powder.

[0066] 6. Screening and packaging: Use a 100-mesh sieve to screen the dried powder; vacuum pack the screened powder and store it away from light.

[0067] Comparative Example 1

[0068] Comparative Example 1 is similar to Example 1, except that: the mass concentration of glucomannan is 1%, the mass concentration of cellulose is 0.5%; the temperature during cross-linking is 50° C.; and other process parameters refer to Example 1.

[0069] Comparative Example 2

[0070] Comparative Example 2 is similar to Example 1, except that: the mass concentration of glucomannan is 4%, the mass concentration of cellulose is 3%; the temperature during cross-linking is 30° C.; and the other process parameters refer to Example 1.

[0071] Experimental Example 1

[0072] The particle size distribution of the sustained-release capsules of Examples 1-3 and Comparative Examples 1-2 was detected.

[0073] The particle size distribution of the sustained-release capsules was measured using a laser particle size analyzer. The results are shown in Table 1.

[0074] Experimental Example 2

[0075] The encapsulation efficiency of the sustained-release capsules of Examples 1-3 and Comparative Examples 1-2 was tested.

[0076] The content of the antibacterial agent in the sustained-release capsules was determined by high performance liquid chromatography (HPLC), and the encapsulation efficiency was calculated. The encapsulation efficiency (EE%) = (actual measured content / theoretical input antibacterial agent content) × 100%. The results are shown in Table 1.

[0077] Experimental Example 3

[0078] The antibacterial agent release amount of the sustained-release capsules of Examples 1-3 and Comparative Examples 1-2 was tested.

[0079] The dialysis bag method was used to study the release behavior of sustained-release capsules in a simulated food environment; 1 g of sustained-release capsules was placed in a dialysis bag, immersed in a pH 6.8 phosphate buffer, and oscillated at a constant temperature at 37°C; samples were taken at regular intervals (at 4h and 72h, respectively), and the content of the antimicrobial agent in the release medium was determined by HPLC.

[0080] Table 1

[0081]

[0082] According to Table 1, as in Example 1, when the mass concentration of glucomannan is 2.5% and the mass concentration of cellulose is 1.5%, the encapsulation rate of the antibacterial agent is high, the particle size is relatively uniform, and the release of the antibacterial agent is stable.

[0083] Comparing Example 1 with Example 2, it can be seen that when the mass concentration of glucomannan and the mass concentration of cellulose decrease, the encapsulation rate of the antibacterial agent decreases, and the release rate of the antibacterial agent is relatively fast.

[0084] Comparing Example 1 with Example 3, it can be seen that when the mass concentration of glucomannan and the mass concentration of cellulose increase, although the encapsulation rate of the antibacterial agent increases, the release rate of the antibacterial agent is too slow.

[0085] By comparing Examples 1 and 2 with Comparative Example 1, it can be seen that when the mass concentration of glucomannan and the mass concentration of cellulose are too low and the cross-linking temperature is too high, although the obtained sustained-release capsules show a relatively stable sustained-release effect, it is difficult to achieve effective encapsulation of the antibacterial agent, the total amount of the antibacterial agent in the sustained-release capsules is small, and the antibacterial effect is poor.

[0086] By comparing Examples 1 and 3 with Comparative Example 2, it can be seen that even if the mass concentration of glucomannan and the mass concentration of cellulose are increased, stickiness is likely to occur when forming microcapsules after cross-linking at a relatively low temperature, resulting in uneven particle size of the sustained-release capsules, and it is difficult to increase the encapsulation rate of the antibacterial agent, thereby making it difficult for the prepared sustained-release capsules to achieve a good and relatively long-lasting antibacterial effect.

[0087] Example 4

[0088] PE and the glucomannan-water-soluble cellulose antibacterial material (sustained-release capsule) of Example 1 were mixed, and the mixture was extruded by a twin-screw extruder to prepare a fresh-keeping film; wherein the mass percentage of the sustained-release capsule was 5%.

[0089] Example 5

[0090] PE and the glucomannan-water-soluble cellulose antibacterial material (sustained-release capsule) of Example 1 were mixed, and the mixture was extruded by a twin-screw extruder to prepare a fresh-keeping film; wherein the mass percentage of the sustained-release capsule was 1%.

[0091] Example 6

[0092] PE and the glucomannan-water-soluble cellulose antibacterial material (sustained-release capsule) of Example 1 were mixed, and the mixture was extruded by a twin-screw extruder to prepare a fresh-keeping film; wherein the mass percentage of the sustained-release capsule was 3%.

[0093] Example 7

[0094] PE and the glucomannan-water-soluble cellulose antibacterial material (sustained-release capsule) of Example 1 were mixed, and the mixture was extruded by a twin-screw extruder to prepare a fresh-keeping film; wherein the mass percentage of the sustained-release capsule was 7%.

[0095] Experimental Example 4

[0096] The cling film of Examples 4-7 was used to test the antibacterial activity; Escherichia coli and Staphylococcus aureus were mixed as indicator bacteria and inoculated on agar medium, and the antibacterial activity of each cling film was tested by the inhibition zone method. The results are shown in Table 2.

[0097] Table 2

[0098]

[0099] According to Table 2, when the mass percentage of the sustained-release capsules is 5%, the plastic wrap has the best antibacterial property; when the mass percentage of the sustained-release capsules is lower than 5% or higher than 5%, the antibacterial effect is reduced.

[0100] Experimental Example 5

[0101] A freshness-keeping test was carried out using the cling film of Example 4 and a commercially available ordinary PE cling film; the test objects were strawberries and chicken breasts, and the test method was to wrap the strawberries and chicken breasts with the cling film of Example 4 and the ordinary PE cling film, respectively, wherein the strawberries wrapped with the cling film of Example 4 were test group 1, the chicken breasts wrapped with the cling film of Example 4 were test group 2, the strawberries wrapped with the ordinary PE cling film were control group 1, and the chicken breasts wrapped with the ordinary PE cling film were control group 2, and then the test groups 1 and 2 and the control groups 1 and 2 were placed under the same room temperature and stored for 72 hours.

[0102] Microbiological testing, sensory evaluation and physical and chemical index testing were carried out on the experimental groups 1 and 2 and the control groups 1 and 2. The results are shown in Table 3.

[0103] Table 3

[0104]

[0105]

[0106] Note: ND means not detected.

[0107] According to Table 3, the sustained-release capsules added to the cling film of Example 4 can effectively inhibit bacteria, thereby improving the preservation effect of food, slowing down the rate of food spoilage, slowing down the rate of decline in food sensory quality, and delaying the process of food rancidity to maintain the nutritional components of food.

[0108] In summary, the preparation method of the glucomannan-water-soluble cellulose antibacterial material of the present invention optimizes the ratio of glucomannan and water-soluble cellulose, can effectively encapsulate the antibacterial agent, and ensures that the antibacterial agent can be stably released, that is, the antibacterial effect of the glucomannan-water-soluble cellulose antibacterial material can be improved and prolonged. Moreover, both glucomannan and water-soluble cellulose are biocompatible materials, ensuring the safety of the glucomannan-water-soluble cellulose antibacterial material.

[0109] The glucomannan-water-soluble cellulose antibacterial material prepared by the preparation method of the invention is used for preparing fresh-keeping film, and can make the fresh-keeping film have a long-lasting antibacterial and fresh-keeping effect.

[0110] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a glucomannan-water-soluble cellulose antibacterial material, characterized in that: include: Prepare an aqueous phase solution using glucomannan and water-soluble cellulose, wherein the mass concentration of the glucomannan is 1.5-3.5%, and the mass concentration of the water-soluble cellulose is 1.0-2.5%; preparing an oil phase solution with an antimicrobial agent and an emulsifier; The oil phase solution is added dropwise to the water phase solution, and high-speed shear emulsification is performed to form a nanoemulsion; adding a cross-linking agent to the nanoemulsion to form a cross-linked emulsion having a network structure; The cross-linked emulsion is prepared into sustained-release capsules.

2. The method for preparing the glucomannan-water-soluble cellulose antibacterial material according to claim 1, characterized in that: The mass concentration of the glucomannan is 2.5%, and the mass concentration of the water-soluble cellulose is 1.5%.

3. The method for preparing the glucomannan-water-soluble cellulose antibacterial material according to claim 1, characterized in that: The water-soluble cellulose includes at least one of hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose and polymerized quaternary ammonium salt-10.

4. The method for preparing the glucomannan-water-soluble cellulose antibacterial material according to claim 1, characterized in that: The emulsifier includes Tween 80, and the cross-linking agent includes at least one of a calcium chloride solution and glutaraldehyde.

5. The method for preparing the glucomannan-water-soluble cellulose antibacterial material according to claim 1, characterized in that: The antibacterial agent comprises at least one of eugenol, carvacrol, thymol, citral, cinnamaldehyde, vanillin, perillaldehyde, citronellol, cumin essential oil and benzyl isothiocyanate.

6. The method for preparing the glucomannan-water-soluble cellulose antibacterial material according to claim 1, characterized in that: The method of adding the crosslinking agent to the nanoemulsion comprises: dropping the crosslinking agent into the nanoemulsion, stirring, and reacting at a temperature of 35-45°C.

7. The method for preparing the glucomannan-water-soluble cellulose antibacterial material according to claim 1, characterized in that: The method for preparing the cross-linked emulsion into sustained-release capsules comprises: spray drying the cross-linked emulsion; and the rotation speed of the high-speed shear emulsification is 10000-15000 rpm.

8. The method for preparing the glucomannan-water-soluble cellulose antibacterial material according to claim 7, characterized in that: The inlet temperature of the spray drying is 170-190° C., the outlet temperature is 80-90° C., the atomization pressure is 0.15-0.25 MPa, and the feed rate is 4-6 mL / min.

9. A glucomannan-water-soluble cellulose antibacterial material, characterized in that: The glucomannan-water-soluble cellulose antibacterial material is prepared by the preparation method of the glucomannan-water-soluble cellulose antibacterial material according to any one of claims 1 to 8.

10. A fresh-keeping film, characterized in that: The raw materials for preparing the fresh-keeping film include resin and the glucomannan-water-soluble cellulose antibacterial material according to claim 9.

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