Slow-release external-control fresh-keeping bag for multi-category food and preparation method of slow-release external-control fresh-keeping bag

Abstract

The invention relates to the technical field of food preservation, in particular to a slow-release external-control preservation bag for multiple kinds of food and a preparation method thereof.The slow-release external-control preservation bag is composed of an external coating material and an internal preservation compound, and the coating material sequentially comprises a high-temperature-resistant layer, a first middle layer, a second middle layer and a heat sealing layer from outside to inside; air holes are formed in the high-temperature-resistant layer and serve as directional channels for the fresh-keeping factors to be slowly released outwards, the middle layer 2 is prepared by melting and mixing various functional substances and directional polypropylene and has antibacterial and hygroscopic properties, in the fresh-keeping factors, hydroxypropyl-beta-cyclodextrin in an active inclusion compound is high in water solubility and inclusion property, and the fresh-keeping effect is good. Sulfonic groups in sulfonated sodium alginate also have certain antioxidant ability, the antibacterial and antioxidant action time of cinnamon essential oil and 6-gingerol is prolonged, the cinnamon essential oil and 6-gingerol have a synergistic interaction with the middle layer 2, and the antibacterial and anti-oxidation antibacterial film has a wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of food preservation technology, and in particular to a slow-release external preservation package for multiple types of food and its preparation method. Background Technology

[0002] With the rapid development of the food industry and the upgrading of consumption, consumers' requirements for food freshness, safety, and shelf life are constantly increasing, making food preservation one of the core needs of the industry. Currently, the mainstream food preservation methods include low-temperature refrigeration, vacuum packaging, and the addition of chemical preservatives, but all of them have obvious limitations: low-temperature refrigeration is costly and cannot completely inhibit the growth of microorganisms; vacuum packaging is only suitable for some foods and has limited preservation effect on foods that are easily oxidized or absorb moisture; directly adding chemical preservatives can easily lead to excessive residues and cannot be flexibly adjusted to meet the preservation needs of different types of food. Existing food preservation bags are mostly single-function, such as oxygen-absorbing preservation bags, dehumidifying preservation bags, and antibacterial preservation bags. They have the following shortcomings and need further improvement: 1. Limited applicability: Oxygen-absorbing preservation bags are only suitable for oxygen-sensitive foods, and dehumidifying preservation bags are only suitable for foods with high water activity. They cannot simultaneously meet the complex preservation needs of multiple food categories, such as pastries (which need to be protected against oxidation and mold), meat products (which need to be protected against microorganisms and browning), and dried aquatic products (which need to be protected against moisture and spoilage). 2. Uncontrollable release rate: Preservatives are mostly released rapidly. If the initial concentration is too high, it will easily lead to changes in the flavor of food. If the concentration is insufficient in the later stage, it will not be able to maintain the preservation effect, and the preservation period is short (usually no more than 15 days).

[0003] Therefore, based on the relevant technologies mentioned above, there is an urgent need to develop a slow-release external preservation package for various types of food and its preparation method. Summary of the Invention

[0004] In view of this, the purpose of this invention is to propose a slow-release external control preservation package for multi-category foods and its preparation method, so as to solve the problems of limited applicability and fast release rate in the prior art.

[0005] To achieve the above objectives, the present invention provides a slow-release external preservation package for various types of food and its preparation method.

[0006] A slow-release external control preservation package for multi-category food, the external control preservation package comprising an outer coating material and an inner preservation complex; The preservation complex includes a preservation carrier and a preservation factor. The preservation medium is food-grade cotton sheet; The preservation factor comprises the following raw materials in parts by weight: Edible alcohol 43-60 parts; active inclusion complex 17.5-21.2 parts; diatomaceous earth 1-2 parts; montmorillonite 2-3.3 parts; green tea extract microspheres 8.1-13.6 parts; plant extract 12.3-17 parts; The coating material consists of a high-temperature resistant layer, an intermediate layer 1, an intermediate layer 2, and a heat-sealing layer from the outside to the inside. The high-temperature resistant layer is provided with vent holes with a diameter of 0.1-0.13 mm.

[0007] Preferably, the thickness of the high-temperature resistant layer is 25-30 μm, the thickness of the intermediate layer 1 is 12-18 μm, the thickness of the intermediate layer 2 is 8-13 μm, and the thickness of the heat-sealing layer is 12-18 μm. The plant extract was obtained by mixing garlic extract, 6-gingerol, and Vaccinium bracteatum berry extract in a mass ratio of 3.8-5:3-5:6-6.9. The active inclusion complex was prepared from cinnamon essential oil, 6-gingerol, sulfonated sodium alginate, hydroxypropyl-β-cyclodextrin and calcium chloride.

[0008] Preferably, the high-temperature resistant layer is formed by extrusion molding of polyethylene terephthalate and oriented polypropylene; The intermediate layer 1 is made of oriented polypropylene, nylon and ethylene-vinyl alcohol through an encapsulation and extrusion molding process. The intermediate layer 2 is obtained by melt blending, twin-screw extrusion granulation, melt spinning, hot air drying and corona treatment of oriented polypropylene, silver ion exchange zeolite, zinc stearate, green tea extract microspheres, nano calcium chloride, chitosan and diatomaceous earth. The heat-sealing layer is formed by co-extrusion blown film of cast polypropylene and ethylene-vinyl alcohol.

[0009] Preferably, the silver ion loading in the silver ion exchange zeolite is 2%-4%; The silver ion exchange zeolite has a particle size of 25-45 nm; The particle size of the nano-calcium chloride is 60-75 nm; The diatomaceous earth has a particle size of 2-4 nm and a specific surface area of ​​≥300 m² / g.

[0010] Preferably, the active inclusion complex is prepared by the following method: Step A1. Add sodium nitrite to deionized water, and after it is completely dissolved, heat it to 85-90°C. Add an aqueous solution of sodium bisulfate with a mass fraction of 18%-20%, and adjust the pH of the system to 8-8.5 with sodium hydroxide. Stir for 2-3 hours to obtain compound A. Step A2. Add compound A dropwise to a 1%-1.5% sodium alginate aqueous solution and stir at 40-47°C for 10-12 hours. After precipitation, wash and freeze-dry to obtain sulfonated sodium alginate. Step A3. Add hydroxypropyl-β-cyclodextrin to a 50% (w / w) aqueous ethanol solution and stir at 55-65°C for 3-4 h to obtain a hydroxypropyl-β-cyclodextrin suspension. Add a 5%-6% (w / w) cinnamon essential oil ethanol solution and a 5%-6% (w / w) 6-gingerol ethanol solution to the hydroxypropyl-β-cyclodextrin suspension and stir at room temperature for 48-50 h. Centrifuge and freeze dry to obtain hydroxypropyl-β-cyclodextrin modified particles. Step A4. After dissolving sodium sulfonate in deionized water, add hydroxypropyl-β-cyclodextrin modified particles, stir for 2-3 hours, and spray the resulting mixture into a 5% (w / w) calcium chloride solution for cross-linking and curing to obtain the active inclusion complex.

[0011] Preferably, the ratio of sodium nitrite, deionized water and sodium bisulfate aqueous solution used in step A1 is 1-2.5g:30-75mL:35-80mL; The volume ratio of the sodium alginate aqueous solution to compound A in step A2 is 200-260:67-90.

[0012] Preferably, the ratio of hydroxypropyl-β-cyclodextrin, aqueous ethanol solution, cinnamon essential oil ethanol solution and 6-gingerol ethanol solution used in step A3 is 2-3g:60-85mL:20-42mL:12-18mL; The ratio of sodium sulfonate, deionized water, hydroxypropyl-β-cyclodextrin modified particles and calcium chloride solution used in step A4 is 1.5-2.2g:150-220mL:8.5-12.2g:300-385mL.

[0013] Preferably, the green tea extract microspheres are prepared as follows: Step B1. Wash, remove dust, and coarsely crush 20-36g of tender green tea leaves and buds. Add 240-400mL of deionized water and soak at 80-90°C for 40-60min to obtain a crude extract. After filtration, vacuum concentration, resin adsorption and elution, sterilization and cooling, and freeze-drying, green tea extract is obtained. Step B2. Add gum arabic and maltodextrin to deionized water, stir well, then add green tea extract until completely dissolved, and freeze-dry to obtain green tea extract microspheres.

[0014] Preferably, the ratio of gum arabic, maltodextrin, deionized water and green tea extract in step B2 is 3.3-5g:1.2-1.5g:40-58mL:18.6-27.4g.

[0015] A method for preparing a slow-release external preservation package for multiple food categories includes the following steps: The preservation compound is transported to the packaging equipment through a conveying pipeline and then heat-sealed with a wrapping material to produce a slow-release external control preservation package for multi-category foods.

[0016] The beneficial effects of this invention are: This invention provides a slow-release external controlled-release preservation package for various food products and its preparation method. The invention combines an external coating material and an internal preservation complex to obtain an external controlled-release preservation package suitable for various foods, possessing slow-release, antibacterial, and antioxidant properties. The coating material, from the outside to the inside, consists of a high-temperature resistant layer, an intermediate layer 1, an intermediate layer 2, and a heat-sealing layer. The high-temperature resistant layer has permeable pores, serving as directional channels for the slow release of preservation factors. The intermediate layer 2 is prepared by melt-blending various functional substances with directional polypropylene, possessing antibacterial and hygroscopic properties, and synergistically enhancing the preservation factors in the preservation complex. In the preservation factor, the active inclusion complex is prepared from cinnamon essential oil, 6-gingerol, sulfonated sodium alginate, hydroxypropyl-β-cyclodextrin, and calcium chloride. Hydroxypropyl-β-cyclodextrin, as the etherified product of β-cyclodextrin, breaks the original intramolecular cyclic hydrogen bonds in β-cyclodextrin, improves water solubility, and has a higher inclusion capacity. In addition, the sulfonic acid group in sulfonated sodium alginate also has a certain antioxidant capacity. The antibacterial and antioxidant effects of cinnamon essential oil and 6-gingerol are prolonged after treatment with sulfonated sodium alginate and hydroxypropyl-β-cyclodextrin, achieving a sustained-release effect. Compared with the existing technology, it has broad application prospects. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0018] The sources and properties of some of the raw materials used in this invention are as follows: Sodium alginate was purchased from Qingdao Haizhilin Biotechnology Development Co., Ltd.; hydroxypropyl-β-cyclodextrin was purchased from Zibo Qianhui Biotechnology Co., Ltd.; Vaccinium bracteatum berry extract was purchased from Xi'an Senran Bioengineering Co., Ltd.; and 6-gingerol was purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.

[0019] Example 1: A method for preparing a slow-release external preservation package for multiple types of food, comprising the following steps: S1. Add 1g of sodium nitrite to 30mL of deionized water, and after it is completely dissolved, heat it to 85°C, add 35mL of sodium bisulfate aqueous solution with a mass fraction of 18%, and adjust the pH of the system to 8 with sodium hydroxide. After stirring for 2h, compound A is obtained. S2. Add 67 mL of compound A dropwise to 200 mL of a 1% sodium alginate aqueous solution, stir at 40°C for 10 h, precipitate, wash, freeze dry to obtain sulfonated sodium alginate; S3. Add 2g of hydroxypropyl-β-cyclodextrin to 60mL of 50% ethanol aqueous solution and stir at 55°C for 3h to obtain a hydroxypropyl-β-cyclodextrin suspension. Add 20mL of 5% cinnamon essential oil ethanol solution and 12mL of 5% 6-gingerol ethanol solution to the hydroxypropyl-β-cyclodextrin suspension and stir at room temperature for 48h. Centrifuge and freeze dry to obtain hydroxypropyl-β-cyclodextrin modified particles. S4. Dissolve 1.5g of sulfonated sodium alginate in 150mL of deionized water, add 8.5g of hydroxypropyl-β-cyclodextrin modified particles, stir for 2h, and spray the resulting mixture into 300mL of 5% calcium chloride solution for cross-linking and curing to obtain the active inclusion complex. S5. Wash, remove dust, and coarsely crush 20g of tender green tea leaves and buds, add 240mL of deionized water, and soak at 80°C for 40min to obtain a crude extract. After filtration, vacuum concentration, resin adsorption and elution, sterilization and cooling, and freeze drying, green tea extract is obtained. S6. Add 3.3g gum arabic and 1.2g maltodextrin to 40mL of deionized water, stir well, then add 18.6g green tea extract until completely dissolved, and freeze dry to obtain green tea extract microspheres. S7. 72g of oriented polypropylene, 3g of silver ion exchange zeolite, 4g of green tea extract microspheres, 6.5g of nano calcium chloride, 3g of diatomaceous earth, 3g of chitosan and 0.2g of zinc stearate were added to a high-speed mixer and mixed for 20min at 1000r / min and 60℃. Then, the mixture was granulated by twin-screw extrusion, melt spun, dried by hot air and corona treated to obtain intermediate layer 2. S8. A high-temperature resistant layer is obtained by extrusion molding of polyethylene terephthalate and oriented polypropylene; an intermediate layer 1 is made by encapsulation extrusion molding of oriented polypropylene, nylon and ethylene-vinyl alcohol; and a heat-sealing layer is obtained by co-extrusion blow molding of cast polypropylene and ethylene-vinyl alcohol. S9. The preservation compound is transported to the packaging equipment through a conveying pipeline and heat-pressed and packaged with a film material. In the film material, the thickness of the high temperature resistant layer is 25μm, the thickness of the intermediate layer 1 is 12μm, the thickness of the intermediate layer 2 is 8μm, and the thickness of the heat-sealing layer is 12μm, which is a slow-release external control preservation package for multi-category food.

[0020] Example 2: A method for preparing a slow-release external preservation package for multiple types of food, comprising the following steps: S1. Add 1.5g of sodium nitrite to 40mL of deionized water, and after it is completely dissolved, heat it to 88°C, add 45mL of sodium bisulfate aqueous solution with a mass fraction of 18%, and adjust the pH of the system to 8 with sodium hydroxide. After stirring for 2.5h, compound A is obtained. S2. 75 mL of compound A was added dropwise to 215 mL of a 1.2% sodium alginate aqueous solution, and the mixture was stirred at 42°C for 11 h. After precipitation, washing, and freeze-drying, sulfonated sodium alginate was obtained. S3. Add 2.4 g of hydroxypropyl-β-cyclodextrin to 65 mL of 50% ethanol aqueous solution and stir at 58°C for 3.5 h to obtain a hydroxypropyl-β-cyclodextrin suspension. Add 25 mL of 5.4% cinnamon essential oil ethanol solution and 14 mL of 5.4% 6-gingerol ethanol solution to the hydroxypropyl-β-cyclodextrin suspension and stir at room temperature for 49 h. Centrifuge and freeze dry to obtain hydroxypropyl-β-cyclodextrin modified particles. S4. Dissolve 1.7g of sulfonated sodium alginate in 170mL of deionized water, add 10g of hydroxypropyl-β-cyclodextrin modified particles, stir for 2.5h, and spray the resulting mixture into 325mL of 5% calcium chloride solution for cross-linking and curing to obtain the active inclusion complex. S5. Wash, remove dust, and coarsely crush 25g of tender green tea leaves and buds, add 270mL of deionized water, and soak at 84°C for 47min to obtain a crude extract. After filtration, vacuum concentration, resin adsorption and elution, sterilization and cooling, and freeze drying, green tea extract is obtained. S6. Add 4g gum arabic and 1.3g maltodextrin to 47mL of deionized water, stir well, then add 21.5g green tea extract until completely dissolved, and freeze dry to obtain green tea extract microspheres. S7. 76g of oriented polypropylene, 3.8g of silver ion exchange zeolite, 4.8g of green tea extract microspheres, 7.2g of nano calcium chloride, 3.8g of diatomaceous earth, 3.8g of chitosan and 0.28g of zinc stearate were added to a high-speed mixer and mixed for 24min at 1200r / min and 66℃. The mixture was then granulated by twin-screw extrusion, melt spun, dried by hot air and corona treated to obtain intermediate layer 2. S8. A high-temperature resistant layer is obtained by extrusion molding of polyethylene terephthalate and oriented polypropylene; an intermediate layer 1 is made by encapsulation extrusion molding of oriented polypropylene, nylon and ethylene-vinyl alcohol; and a heat-sealing layer is obtained by co-extrusion blow molding of cast polypropylene and ethylene-vinyl alcohol. S9. The preservation compound is transported to the packaging equipment through a conveying pipeline and heat-pressed and packaged with a film material. In the film material, the thickness of the high temperature resistant layer is 30μm, the thickness of the intermediate layer 1 is 12μm, the thickness of the intermediate layer 2 is 10μm, and the thickness of the heat-sealing layer is 12μm, which is a slow-release external control preservation package for multi-category food.

[0021] Example 3: A method for preparing a slow-release external preservation package for multiple types of food, comprising the following steps: S1. Add 2g of sodium nitrite to 55mL of deionized water, and after it is completely dissolved, heat it to 88°C. Add 65mL of sodium bisulfate aqueous solution with a mass fraction of 19%, and adjust the pH of the system to 8.5 with sodium hydroxide. After stirring for 2.5h, compound A is obtained. S2. Add 82 mL of compound A dropwise to 240 mL of sodium alginate aqueous solution with a mass fraction of 1.4%, stir at 45°C for 11 h, precipitate, wash, freeze dry to obtain sulfonated sodium alginate; S3. 2.7 g of hydroxypropyl-β-cyclodextrin was added to 78 mL of 50% ethanol aqueous solution and stirred at 62°C for 3.5 h to obtain a hydroxypropyl-β-cyclodextrin suspension. 36 mL of 5.7% cinnamon essential oil ethanol solution and 16 mL of 5.7% 6-gingerol ethanol solution were added to the hydroxypropyl-β-cyclodextrin suspension and stirred at room temperature for 49 h. After centrifugation and freeze-drying, hydroxypropyl-β-cyclodextrin modified particles were obtained. S4. Dissolve 2g of sulfonated sodium alginate in 200mL of deionized water, add 11.3g of hydroxypropyl-β-cyclodextrin modified particles, stir for 3h, and spray the resulting mixture into 360mL of 5% calcium chloride solution for cross-linking and curing to obtain the active inclusion complex. S5. Wash, remove dust, and coarsely crush 30g of tender green tea leaves and buds, add 340mL of deionized water, and soak at 87°C for 53min to obtain a crude extract. After filtration, vacuum concentration, resin adsorption and elution, sterilization and cooling, and freeze drying, green tea extract is obtained. S6. Add 4.3g gum arabic and 1.4g maltodextrin to 51mL of deionized water, stir well, then add 25.4g green tea extract until completely dissolved, and freeze dry to obtain green tea extract microspheres. S7. Add 80g of oriented polypropylene, 4.2g of silver ion exchange zeolite, 5.5g of green tea extract microspheres, 7.7g of nano calcium chloride, 4.2g of diatomaceous earth, 4.2g of chitosan and 0.3g of zinc stearate to a high-speed mixer. Mix for 27min at 1400r / min and 70℃. Then, granulate by twin-screw extrusion, melt spin, dry with hot air and corona treatment to obtain intermediate layer 2. S8. A high-temperature resistant layer is obtained by extrusion molding of polyethylene terephthalate and oriented polypropylene; an intermediate layer 1 is made by encapsulation extrusion molding of oriented polypropylene, nylon and ethylene-vinyl alcohol; and a heat-sealing layer is obtained by co-extrusion blow molding of cast polypropylene and ethylene-vinyl alcohol. S9. The preservation compound is transported to the packaging equipment through a conveying pipeline and heat-sealed with a film material. The film material has a high-temperature resistant layer thickness of 25μm, an intermediate layer 1 thickness of 15μm, an intermediate layer 2 thickness of 10μm, and a heat-sealing layer thickness of 15μm, which is a slow-release external control preservation package for multi-category foods.

[0022] Example 4: A method for preparing a slow-release external preservation package for multiple types of food, comprising the following steps: S1. Add 2.5g of sodium nitrite to 75mL of deionized water, and after it is completely dissolved, heat it to 90°C, add 80mL of sodium bisulfate aqueous solution with a mass fraction of 20%, and adjust the pH of the system to 8.5 with sodium hydroxide. After stirring for 3h, compound A is obtained. S2. Add 90 mL of compound A dropwise to 260 mL of a 1.5% sodium alginate aqueous solution, stir at 47°C for 12 h, precipitate, wash, freeze dry to obtain sulfonated sodium alginate; S3. Add 3g of hydroxypropyl-β-cyclodextrin to 85mL of 50% ethanol aqueous solution and stir at 65°C for 4h to obtain a hydroxypropyl-β-cyclodextrin suspension. Add 42mL of 6% cinnamon essential oil ethanol solution and 18mL of 6% 6% 6-gingerol ethanol solution to the hydroxypropyl-β-cyclodextrin suspension and stir at room temperature for 50h. Centrifuge and freeze dry to obtain hydroxypropyl-β-cyclodextrin modified particles. S4. Dissolve 2.2g of sulfonated sodium alginate in 220mL of deionized water, add 12.2g of hydroxypropyl-β-cyclodextrin modified particles, stir for 3h, and spray the resulting mixture into 385mL of 5% calcium chloride solution for cross-linking and curing to obtain the active inclusion complex. S5. Wash, remove dust, and coarsely crush 36g of tender green tea leaves and buds, add 400mL of deionized water, and soak at 90°C for 60min to obtain a crude extract. After filtration, vacuum concentration, resin adsorption and elution, sterilization and cooling, and freeze drying, green tea extract is obtained. S6. Add 5g gum arabic and 1.5g maltodextrin to 58mL of deionized water, stir well, then add 27.4g green tea extract until completely dissolved, and freeze dry to obtain green tea extract microspheres. S7. Add 85g of oriented polypropylene, 5g of silver ion exchange zeolite, 6.2g of green tea extract microspheres, 8.3g of nano calcium chloride, 5g of diatomaceous earth, 5g of chitosan and 0.4g of zinc stearate to a high-speed mixer. Mix for 30min at 1500r / min and 80℃. Then, granulate by twin-screw extrusion, melt spin, dry with hot air and corona treatment to obtain intermediate layer 2. S8. A high-temperature resistant layer is obtained by extrusion molding of polyethylene terephthalate and oriented polypropylene; an intermediate layer 1 is made by encapsulation extrusion molding of oriented polypropylene, nylon and ethylene-vinyl alcohol; and a heat-sealing layer is obtained by co-extrusion blow molding of cast polypropylene and ethylene-vinyl alcohol. S9. The preservation compound is transported to the packaging equipment through a conveying pipeline and heat-sealed using a coating material. The coating material has a high-temperature resistant layer thickness of 30μm, an intermediate layer 1 thickness of 18μm, an intermediate layer 2 thickness of 13μm, and a heat-sealing layer thickness of 18μm, thus forming a slow-release external control preservation package for multi-category foods.

[0023] Comparative Example 1: Compared with Example 1, this comparative example did not add active inclusion complexes during the preparation of the preservation factor. All other steps and parameters were the same, and will not be repeated here. The final result was an externally controlled preservation package.

[0024] Comparative Example 2: Compared with Example 1, this comparative example did not add green tea extract microspheres during the preparation of the preservation factor. All other steps and parameters were the same, and will not be repeated here. The final result was an externally controlled preservation package.

[0025] Comparative Example 3: Compared with Example 1, this comparative example did not add plant extracts during the preparation of the preservation factor. All other steps and parameters were the same, and will not be repeated here. The final result was an externally controlled preservation package.

[0026] Comparative Example 4: S1. Add 1g of sodium nitrite to 30mL of deionized water, and after it is completely dissolved, heat it to 85°C, add 35mL of sodium bisulfate aqueous solution with a mass fraction of 18%, and adjust the pH of the system to 8 with sodium hydroxide. After stirring for 2h, compound A is obtained. S2. Add 67 mL of compound A dropwise to 200 mL of a 1% sodium alginate aqueous solution, stir at 40°C for 10 h, precipitate, wash, freeze dry to obtain sulfonated sodium alginate; S3. Add 2g of hydroxypropyl-β-cyclodextrin to 60mL of 50% ethanol aqueous solution and stir at 55°C for 3h to obtain a hydroxypropyl-β-cyclodextrin suspension. Add 20mL of 5% cinnamon essential oil ethanol solution and 12mL of 5% 6-gingerol ethanol solution to the hydroxypropyl-β-cyclodextrin suspension and stir at room temperature for 48h. Centrifuge and freeze dry to obtain hydroxypropyl-β-cyclodextrin modified particles. S4. Dissolve 1.5g of sulfonated sodium alginate in 150mL of deionized water, add 8.5g of hydroxypropyl-β-cyclodextrin modified particles, stir for 2h, and spray the resulting mixture into 300mL of 5% calcium chloride solution for cross-linking and curing to obtain the active inclusion complex. S5. Wash, remove dust, and coarsely crush 20g of tender green tea leaves and buds, add 240mL of deionized water, and soak at 80°C for 40min to obtain a crude extract. After filtration, vacuum concentration, resin adsorption and elution, sterilization and cooling, and freeze drying, green tea extract is obtained. S6. Add 3.3g gum arabic and 1.2g maltodextrin to 40mL of deionized water, stir well, then add 18.6g green tea extract until completely dissolved, and freeze dry to obtain green tea extract microspheres. S7. A high-temperature resistant layer is obtained by extrusion molding of polyethylene terephthalate and oriented polypropylene; an intermediate layer is made by encapsulation extrusion molding of oriented polypropylene, nylon and ethylene-vinyl alcohol; and a heat-sealing layer is obtained by co-extrusion blow molding of cast polypropylene and ethylene-vinyl alcohol. S8. The preservation compound is transported to the packaging equipment through a conveying pipeline and then heat-pressed and packaged with a film material. The film material has a high-temperature resistant layer thickness of 25μm, an intermediate layer thickness of 12μm, and a heat-sealing layer thickness of 12μm, which is a slow-release external control preservation package for multi-category foods.

[0027] Comparative Example 5: S1. Add 1g of sodium nitrite to 30mL of deionized water, and after it is completely dissolved, heat it to 85°C, add 35mL of sodium bisulfate aqueous solution with a mass fraction of 18%, and adjust the pH of the system to 8 with sodium hydroxide. After stirring for 2h, compound A is obtained. S2. Add 67 mL of compound A dropwise to 200 mL of a 1% sodium alginate aqueous solution, stir at 40°C for 10 h, precipitate, wash, freeze dry to obtain sulfonated sodium alginate; S3. Add 2g of hydroxypropyl-β-cyclodextrin to 60mL of 50% ethanol aqueous solution and stir at 55°C for 3h to obtain a hydroxypropyl-β-cyclodextrin suspension. Add 20mL of 5% cinnamon essential oil ethanol solution and 12mL of 5% 6-gingerol ethanol solution to the hydroxypropyl-β-cyclodextrin suspension and stir at room temperature for 48h. Centrifuge and freeze dry to obtain hydroxypropyl-β-cyclodextrin modified particles. S4. Dissolve 1.5g of sulfonated sodium alginate in 150mL of deionized water, add 8.5g of hydroxypropyl-β-cyclodextrin modified particles, stir for 2h, and spray the resulting mixture into 300mL of 5% calcium chloride solution for cross-linking and curing to obtain the active inclusion complex. S5. Wash, remove dust, and coarsely crush 20g of tender green tea leaves and buds, add 240mL of deionized water, and soak at 80°C for 40min to obtain a crude extract. After filtration, vacuum concentration, resin adsorption and elution, sterilization and cooling, and freeze drying, green tea extract is obtained. S6. Add 3.3g gum arabic and 1.2g maltodextrin to 40mL of deionized water, stir well, then add 18.6g green tea extract until completely dissolved, and freeze dry to obtain green tea extract microspheres. S7. Add 72g of oriented polypropylene, 6.5g of nano-calcium chloride, 3g of diatomaceous earth, 3g of chitosan and 0.2g of zinc stearate to a high-speed mixer, mix for 20min at 1000r / min and 60℃, then granulate by twin-screw extrusion, melt spin, dry with hot air and corona treatment to obtain intermediate layer 2. S8. A high-temperature resistant layer is obtained by extrusion molding of polyethylene terephthalate and oriented polypropylene; an intermediate layer 1 is made by encapsulation extrusion molding of oriented polypropylene, nylon and ethylene-vinyl alcohol; and a heat-sealing layer is obtained by co-extrusion blow molding of cast polypropylene and ethylene-vinyl alcohol. S9. The preservation compound is transported to the packaging equipment through a conveying pipeline and heat-pressed and packaged with a film material. In the film material, the thickness of the high temperature resistant layer is 25μm, the thickness of the intermediate layer 1 is 12μm, the thickness of the intermediate layer 2 is 8μm, and the thickness of the heat-sealing layer is 12μm, which is a slow-release external control preservation package for multi-category food.

[0028] Comparative Example 6: S1. Add 2g of β-cyclodextrin to 60mL of 50% ethanol aqueous solution and stir at 55°C for 3h to obtain a β-cyclodextrin suspension. Add 20mL of 5% cinnamon essential oil ethanol solution and 12mL of 5% 6-gingerol ethanol solution to the β-cyclodextrin suspension and stir at room temperature for 48h. Centrifuge and freeze dry to obtain β-cyclodextrin modified particles. S2. Dissolve 1.5g sodium alginate in 150mL of deionized water, add 8.5g β-cyclodextrin modified particles, stir for 2h, and spray the resulting mixture into 300mL of 5% calcium chloride solution for cross-linking and curing to obtain the active inclusion complex. S3. Wash, remove dust, and coarsely crush 20g of tender green tea leaves and buds, add 240mL of deionized water, and soak at 80°C for 40min to obtain a crude extract. After filtration, vacuum concentration, resin adsorption and elution, sterilization and cooling, and freeze drying, green tea extract is obtained. S4. Add 3.3g gum arabic and 1.2g maltodextrin to 40mL of deionized water, stir well, then add 18.6g green tea extract until completely dissolved, and freeze dry to obtain green tea extract microspheres. S5. 72g of oriented polypropylene, 3g of silver ion exchange zeolite, 4g of green tea extract microspheres, 6.5g of nano calcium chloride, 3g of diatomaceous earth, 3g of chitosan and 0.2g of zinc stearate were added to a high-speed mixer and mixed for 20min at 1000r / min and 60℃. Then, the mixture was granulated by twin-screw extrusion, melt spun, dried by hot air and corona treated to obtain intermediate layer 2. S6. A high-temperature resistant layer is obtained by extrusion molding of polyethylene terephthalate and oriented polypropylene; an intermediate layer 1 is made by encapsulation extrusion molding of oriented polypropylene, nylon and ethylene-vinyl alcohol; and a heat-sealing layer is obtained by co-extrusion blow molding of cast polypropylene and ethylene-vinyl alcohol. S7. The preservation compound is transported to the packaging equipment through a conveying pipeline and heat-pressed and packaged with a film material. In the film material, the thickness of the high temperature resistant layer is 25μm, the thickness of the intermediate layer 1 is 12μm, the thickness of the intermediate layer 2 is 8μm, and the thickness of the heat-sealing layer is 12μm, which is a slow-release external control preservation package for multi-category food.

[0029] Comparative Example 7: Compared with Example 1, this comparative example only replaces "the thickness of the high-temperature resistant layer is 25μm, the thickness of the intermediate layer 1 is 12μm, the thickness of the intermediate layer 2 is 8μm, and the thickness of the heat-sealing layer is 12μm" with "the thickness of the high-temperature resistant layer is 20μm, the thickness of the intermediate layer 1 is 9μm, the thickness of the intermediate layer 2 is 16μm, and the thickness of the heat-sealing layer is 12μm". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, an external control preservation bag is obtained.

[0030] Comparative Example 8: Compared with Example 1, this comparative example only replaces "the thickness of the high-temperature resistant layer is 25μm, the thickness of the intermediate layer 1 is 12μm, the thickness of the intermediate layer 2 is 8μm, and the thickness of the heat-sealing layer is 12μm" with "the thickness of the high-temperature resistant layer is 25μm, the thickness of the intermediate layer 1 is 14μm, the thickness of the intermediate layer 2 is 4μm, and the thickness of the heat-sealing layer is 14μm". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, an external control preservation bag is obtained.

[0031] Performance testing: The external preservation packages prepared in Examples 1-4 and Comparative Examples 1-8 were respectively placed into 45g sliced ​​cake packages and sealed. The packages were placed in a constant temperature incubator (25±2℃) and the samples were collected and processed according to the methods in GB4789.1-2016 "National Food Safety Standard General Rules for Microbiological Examination of Food". The samples were tested according to the methods in GB4789.15-2016 "National Food Safety Standard Microbiological Examination of Food for Counting of Molds and Yeasts". The number of molds (CFU / g) was tested at 3d, 15d, 30d, 60d, 180d and 240d respectively. The external preservation packages prepared in Examples 1-4 and Comparative Examples 1-8 were respectively placed into 400g sausages and sealed. After 15 days in a constant temperature and humidity chamber at 20℃ and 50%, 10 experienced judges were invited to conduct sensory evaluations on the 12 groups of sausages. The sensory evaluation mainly focused on four aspects: color, taste, aroma, and texture. Each indicator had a maximum score of 10 points, with a minimum of 0 points. A weighted method was used to calculate the total score, with a weighting coefficient of 0.2 for color, 0.3 for taste, 0.3 for aroma, and 0.2 for texture. The scoring criteria are shown in Table 2.

[0032] Table 1. Summary of experimental data from Examples 1-4 and Comparative Examples 1-8 project 3d(CFU / g) 15d (CFU / g) 30d (CFU / g) 60d(CFU / g) 180d(CFU / g) 240d(CFU / g) Example 1 ＜10 ＜10 ＜10 ＜10 ＜10 ＜10 Example 2 ＜10 ＜10 ＜10 ＜10 ＜10 ＜10 Example 3 ＜10 ＜10 ＜10 ＜10 ＜10 ＜10 Example 4 ＜10 ＜10 ＜10 ＜10 ＜10 ＜10 Comparative Example 1 ＜10 ＜10 ＜10 ＜10 ＞10 - Comparative Example 2 ＜10 ＜10 ＜10 ＜10 ＜10 ＞10 Comparative Example 3 ＜10 ＜10 ＜10 ＜10 ＜10 ＞10 Comparative Example 4 ＜10 ＜10 ＜10 ＜10 ＜10 ＞10 Comparative Example 5 ＜10 ＜10 ＜10 ＜10 ＜10 ＞10 Comparative Example 6 ＜10 ＜10 ＜10 ＜10 ＜10 ＞10 Comparative Example 7 ＜10 ＜10 ＜10 ＜10 ＜10 ＜10 Comparative Example 8 ＜10 ＜10 ＜10 ＜10 ＜10 ＞10 Table 2 Scoring Criteria project 8-10 points 5-7 points 4 points and below Color The lean meat is bright red or jujube red, while the fat is milky white, with distinct colors and a glossy appearance. The lean meat is dark red, and the fat is milky white, with distinct colors and a glossy appearance. The lean meat is dark red, and the fat is gray and dull. Flavor It has the inherent flavor of sausage and the fresh aroma of vegetables, with no unpleasant taste. It has the inherent flavor of sausage, with a slight vegetable taste and no other off-flavors. It has a distinct vegetable or other unpleasant odor. Organizational status The tissue is compact, free of cartilage and other foreign matter, with a clean cut surface and no pores. The tissue is relatively compact, with some elasticity, and the cut surface is relatively neat with a small number of pores. The tissue is loose, with low elasticity, an irregular cut surface, and numerous pores. taste Fine and even texture, with good chewing properties It has a rough texture and average chewing performance. Rough texture and poor chewing ability Table 3 Summary of experimental data from Examples 1-4 and Comparative Examples 1-8 project Color Flavor Organizational status taste Example 1 9 9 8 9 Example 2 8 8 9 9 Example 3 8 9 9 9 Example 4 9 9 8 9 Comparative Example 1 6 7 7 6 Comparative Example 2 7 7 7 6 Comparative Example 3 7 8 7 7 Comparative Example 4 6 7 6 6 Comparative Example 5 7 7 6 7 Comparative Example 6 8 7 8 7 Comparative Example 7 8 8 8 7 Comparative Example 8 7 8 8 8 Data Analysis: As can be seen from Tables 1-3, the external control preservation package prepared by this invention has a better preservation effect and a longer preservation time. This may be because the packaging material consists of a high-temperature resistant layer, an intermediate layer 1, an intermediate layer 2, and a heat-sealing layer from the outside to the inside. The high-temperature resistant layer has vents that act as directional channels for the slow release of preservation factors. The intermediate layer 2 is prepared by melt-blending various functional substances with directional polypropylene, possessing antibacterial and hygroscopic properties, and synergistically enhancing the preservation factors in the preservation complex. Among the preservation factors, active inclusion... The product was prepared from cinnamon essential oil, 6-gingerol, sulfonated sodium alginate, hydroxypropyl-β-cyclodextrin and calcium chloride. Hydroxypropyl-β-cyclodextrin, as the etherified product of β-cyclodextrin, disrupts the original intramolecular cyclic hydrogen bonds in β-cyclodextrin, improves water solubility, and has a higher inclusion capacity. In addition, the sulfonic acid group in sulfonated sodium alginate also has a certain antioxidant capacity. The antibacterial and antioxidant effects of cinnamon essential oil and 6-gingerol after treatment with sulfonated sodium alginate and hydroxypropyl-β-cyclodextrin are prolonged, achieving a sustained-release effect. Comparative Examples 1-3, due to changes in the composition of the preservative factor, had shorter preservation times. This may be because green tea extract, plant extract, and active inclusion complex are important components of the preservative factor, and the three work synergistically to have antibacterial, antioxidant, and preservative effects. Comparative Example 4 had a shorter preservation time because it did not add intermediate layer 2 to the coating material, and Comparative Example 5 had a shorter preservation time because it did not add antibacterial green tea extract, chitosan and silver ion exchange zeolite to intermediate layer 2. This may be because the oriented polypropylene in intermediate layer 2 has good compatibility with the high temperature resistant layer and intermediate layer 1, and its certain thickness can also delay the release of the preservation complex. The functional substances melt-blended with oriented polypropylene give the outer control preservation bag a dual preservation effect, achieving synergistic effect between the coating material and the preservation complex. Comparative Example 6, by changing the composition of the active inclusion complex, had a shorter shelf life. This may be because the active inclusion complex, through the cavity loading of hydroxypropyl-β-cyclodextrin and the cross-linking and solidification of sodium sulfonate and calcium chloride, can delay the degradation of cinnamon essential oil and 6-gingerol. Furthermore, hydroxypropyl-β-cyclodextrin, as an etherified product of β-cyclodextrin, breaks the original intramolecular cyclic hydrogen bonds in β-cyclodextrin, improves water solubility, and has a higher inclusion capacity. The sulfonic acid groups in sodium sulfonate also have certain antioxidant properties. Compared with β-cyclodextrin and sodium alginate, it has a stronger inclusion capacity for the core material, resulting in a better sustained-release effect of the core material. Comparative Examples 7 and 8 showed shorter preservation times by increasing and decreasing the thickness of the intermediate layer 2. This may be because when the intermediate layer 2 is too thick, it may lead to excessive moisture absorption, which prevents some areas of the coating material from absorbing moisture, greatly increasing the relative humidity and thus providing conditions for mold growth. When the intermediate layer 2 is too thin, its moisture absorption and antibacterial effect is not obvious.

[0033] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0034] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A slow-release, externally controlled, fresh-keeping package for multi-category food, characterized in that, The external control fresh-keeping bag comprises an external bag film material and an internal fresh-keeping compound; The fresh-keeping compound comprises a fresh-keeping carrier and a fresh-keeping factor; The fresh-keeping carrier is an edible cotton sheet; The fresh-keeping factor comprises the following raw materials in mass parts: 43-60 parts of edible alcohol; 17.5-21.2 parts of active inclusion compound; 1-2 parts of diatomite; 2-3.3 parts of montmorillonite; 8.1-13.6 parts of green tea extract microspheres; 12.3-17 parts of plant extract; The bag film material comprises, from outside to inside, a high-temperature-resistant layer, an intermediate layer 1, an intermediate layer 2 and a heat-sealing layer, and the high-temperature-resistant layer is provided with air-permeable holes with a size of 0.1-0.13 mm.

2. The multi-category food slow-release type external control fresh-keeping package according to claim 1, characterized in that, The thickness of the high-temperature-resistant layer is 25-30 μm, the thickness of the intermediate layer 1 is 12-18 μm, the thickness of the intermediate layer 2 is 8-13 μm, and the thickness of the heat-sealing layer is 12-18 μm. The plant extract is obtained by mixing garlic extract, 6-gingerol and Vaccinium bracteatum berry extract in a mass ratio of 3.8-5:3-5:6-6.

9. The active inclusion compound is prepared from cinnamon essential oil, 6-gingerol, sulfonated sodium alginate, hydroxypropyl-β-cyclodextrin and calcium chloride.

3. The multi-category food slow-release type external control fresh-keeping package according to claim 1, characterized in that, The high-temperature-resistant layer is extruded from polyethylene terephthalate and oriented polypropylene. The intermediate layer 1 is made by wrapping extrusion molding process from oriented polypropylene, nylon and ethylene-vinyl alcohol. The intermediate layer 2 is obtained by melt blending, double-screw extrusion granulation, melt spinning, hot air drying and corona treatment from oriented polypropylene, silver ion-exchanged zeolite, zinc stearate, green tea extract microspheres, nano calcium chloride, chitosan and diatomite. The heat-sealing layer is made by flow casting polypropylene and ethylene-vinyl alcohol co-extrusion blown film molding.

4. The multi-category food slow-release type external control fresh-keeping bag according to claim 3, characterized in that, The silver ion-exchanged zeolite has a silver ion loading of 2%-4%. The silver ion-exchanged zeolite has a particle size of 25-45 nm. The nano calcium chloride has a particle size of 60-75 nm. The diatomite has a particle size of 2-4 nm and a specific surface area of ≥300 m² / g.

5. The multi-category food slow-release, external-control fresh-keeping package according to claim 1, characterized in that, The preparation method of the active inclusion compound is as follows: Step A1. Sodium nitrite is added to deionized water, completely dissolved, heated to 85-90°C, and then 18%-20% sodium bisulfate aqueous solution is added, and the pH of the system is adjusted to 8-8.5 with sodium hydroxide, and stirred for 2-3 h to obtain compound A; Step A2. Compound A is added dropwise to 1%-1.5% sodium alginate aqueous solution, and stirred at 40-47°C for 10-12 h, then precipitated, washed and freeze-dried to obtain sulfonated sodium alginate; Step A3. Hydroxypropyl-β-cyclodextrin is added to 50% ethanol aqueous solution, stirred at 55-65°C for 3-4 h to obtain a hydroxypropyl-β-cyclodextrin suspension, and then 5%-6% cinnamon essential oil ethanol solution and 5%-6% 6-gingerol ethanol solution are added to the hydroxypropyl-β-cyclodextrin suspension, stirred at room temperature for 48-50 h, centrifuged and freeze-dried to obtain hydroxypropyl-β-cyclodextrin modified particles; Step A4. After the sulfonated sodium alginate was dissolved in deionized water, the hydroxypropyl-β-cyclodextrin modified particles were added, and stirred for 2-3 h. The obtained mixture was sprayed into a 5% calcium chloride solution for cross-linking and solidification to obtain the active inclusion compound.

6. The modified release, external controlled, fresh keeping package for multiple food categories according to claim 5, characterized in that, The amount ratio of sodium nitrite, deionized water and sodium bisulfate aqueous solution in step A1 was 1-2.5 g: 30-75 mL: 35-80 mL. The volume ratio of sodium alginate aqueous solution and compound A in step A2 was 200-260: 67-90.

7. The multi-category food slow-release type, external control fresh-keeping package according to claim 5, characterized in that, The amount ratio of hydroxypropyl-β-cyclodextrin, ethanol aqueous solution, cinnamomum oil ethanol solution and 6-gingerol ethanol solution in step A3 was 2-3 g: 60-85 mL: 20-42 mL: 12-18 mL. The amount ratio of sulfonated sodium alginate, deionized water, hydroxypropyl-β-cyclodextrin modified particles and calcium chloride solution in step A4 was 1.5-2.2 g: 150-220 mL: 8.5-12.2 g: 300-385 mL.

8. The multi-category food slow-release, external-control fresh-keeping package according to claim 1, characterized in that, The preparation method of the green tea extract microspheres was as follows: Step B1. After 20-36 g of green tea tender leaves and tender buds were washed, dusted, and coarsely crushed, 240-400 mL of deionized water was added, and the mixture was immersed at 80-90 °C for 40-60 min to obtain a crude extract. The crude extract was filtered, vacuum concentrated, adsorbed and eluted by resin, sterilized and cooled, and freeze-dried to obtain the green tea extract; Step B2. The gum arabic and malt dextrin were added to deionized water, stirred until uniform, and then the green tea extract was added until completely dissolved. The mixture was freeze-dried to obtain the green tea extract microspheres.

9. The modified release, external controlled, fresh keeping package for multiple food categories according to claim 8, characterized in that, The amount ratio of gum arabic, malt dextrin, deionized water and green tea extract in step B2 was 3.3-5 g: 1.2-1.5 g: 40-58 mL: 18.6-27.4 g.

10. The process for the preparation of the slow release, externally controlled, fresh- keeping package for multiple category food products according to any one of claims 1-9, characterized in that, The method comprises the following steps: The preservative complex was delivered to the packaging equipment through a delivery pipeline and was heat-pressed and packaged by a coating material to obtain the slow-release external control preservative package for multiple types of food. The method comprises the following steps: The preservative complex was delivered to the packaging equipment through a delivery pipeline and was heat-pressed and packaged by a coating material to obtain the slow-release external control preservative package for multiple types of food.