A full life cycle green type sea squirt collagen-based antibacterial film and a preparation method thereof

Abstract

The application discloses a full-life-cycle green type sea tunic collagen-based antibacterial film and a preparation method thereof. Marine fouling organism, i.e., a real sea tunic, is used as a raw material for preparing the collagen film, and the preparation process mainly comprises the following steps: destroying the hydrogen bond between the closely gathered collagen fibers in the tissue through a strong polar hydrogen bond breaker, i.e., a urea solution, and mechanical action, obtaining micro-nano-sized collagen fibers, then performing suction filtration on the suspension, quickly obtaining a collagen fiber film, and then soaking the film in a chitosan solution, and finally preparing the collagen-based antibacterial film. The material has a short preparation time, only involves urea and sodium chloride reagents in the preparation process, and the urea solution generated in the experiment process can be naturally air-dried and recycled through evaporation crystallization. The collagen-based antibacterial film meets the sustainable development concept from the selection of raw materials, to the processing and preparation process, to the disposal of the product after use, and is a full-life-cycle green type food packaging film.

Description

Technical Field

[0001] This invention belongs to the field of green food processing, specifically relating to a green sea squirt collagen-based antibacterial film with a complete life cycle and its preparation method. Background Technology

[0002] With the improvement of living standards in my country, the biodegradability of packaging materials and their impact on food safety have received widespread attention. Currently, the mainstream food packaging materials are mainly petroleum-based polymers. However, due to the non-renewable, difficult-to-degrade, and low biocompatibility of petroleum-based polymers, the global environmental situation is becoming increasingly severe, leading to growing interest in the development of biomass food packaging materials. China is a major maritime nation with abundant marine biological resources. Marine bio-derived collagen, with its abundant raw material sources and unique structure and physicochemical properties, has become a hot topic in biomass resource development research and has broad application prospects.

[0003] Collagen is widely available and possesses excellent biodegradability, biocompatibility, and film-forming properties. Therefore, using collagen films as a substrate in food packaging has natural advantages. In food packaging, collagen films are primarily used to ensure food quality and extend shelf life. Eurygmus, one of the main species of sea squirts, has strong reproductive, growth, and survival capabilities. Often attached to ship hulls or fishing nets, it has become one of the world's major pollutants. Eurygmus mainly consists of a capsule and internal tissue. The internal soft tissue is rich in collagen. Therefore, developing Eurygmus for use as food packaging films can not only achieve high-value utilization of marine biomass but also alleviate marine environmental pollution.

[0004] Collagen membranes prepared using existing technologies typically involve first extracting collagen using an acid-enzymatic method, followed by casting. The collagen extraction process utilizes numerous chemical reagents, such as sodium carbonate, sodium chloride, acetic acid, and pepsin. The extraction steps are also quite complex, including pretreatment, defatting, protein removal, acid dissolution, salting out, re-acid dissolution, dialysis, and freeze-drying. The extensive use of chemical reagents and the complexity of the extraction process result in high economic costs, a long extraction cycle, and significant environmental impact. Furthermore, the natural drying of the obtained collagen solution after casting is time-consuming, and the high viscosity of the collagen solution leads to poor membrane uniformity. Summary of the Invention

[0005] The purpose of this invention is to provide a green, life-cycle-oriented sea squirt collagen-based antibacterial membrane and its preparation method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a green, life-cycle-oriented sea squirt collagen-based antibacterial membrane includes the following steps:

[0008] 1) Preparation of collagen membrane:

[0009] ① After removing the shell and viscera of the sea squirt, chop it up and add 5-15 times the volume (v / v) of 1-3 mol / L sodium chloride solution. Let it stand at 0-4 ℃ for 9-15 h, then rinse it with deionized water, and then add 5-15 times the volume of 5-20 mg / mL urea solution.

[0010] ② Use a high-speed homogenizer to stir at a speed of 10000-15000 r / min 1-3 times, each time for 1-3 minutes;

[0011] ③ After homogenization, place the mixture in a freezer and freeze for 3-5 hours. After thawing slightly, immediately use a high-speed homogenizer to stir 1-3 times at a speed of 10000-15000 r / min, each time for 1-3 minutes.

[0012] ④ Repeat step ③ 1-2 times;

[0013] ⑤ Pour the homogenized liquid into a vacuum filtration device to form a membrane. After filtration, peel off the membrane and rinse it repeatedly with distilled water to remove urea. Place the rinsed membrane in a constant temperature and humidity chamber (humidity 80-90%, temperature 15-25 ℃) to dry for 1-3 hours to obtain a collagen membrane.

[0014] 2) Preparation of collagen-based antibacterial membrane: The collagen membrane was immersed in chitosan solution for 1-3 seconds and then removed and dried at room temperature to obtain the collagen-based antibacterial membrane.

[0015] The concentration of the chitosan solution is 1-3% (w / v), and its preparation method is as follows: 0.5-1.5 g of low molecular weight chitosan powder is dispersed in 50 mL of 1% (v / v) acetic acid solution, and gently stirred at room temperature until completely dissolved.

[0016] This invention uses the marine fouling organism *Utricularia salina* as a raw material for preparing collagen membranes. The preparation process mainly involves using a highly polar hydrogen bond disruptor, urea solution, and mechanical action to break the hydrogen bonds between tightly aggregated collagen fibers in the tissue, obtaining micro- and nano-sized collagen fibers. The suspension is then filtered to rapidly obtain a collagen fiber membrane, which is subsequently immersed in a chitosan solution to ultimately prepare a collagen-based antibacterial membrane. This material has a short preparation time, involves only urea and sodium chloride reagents, and the urea solution generated during the experiment can be naturally dried and recovered through evaporation and crystallization.

[0017] Compared with collagen membranes obtained by acid enzymatic methods, sea squirt-based antibacterial membranes, in addition to the aforementioned advantages of short preparation time, low economic cost, and environmental friendliness, also possess outstanding characteristics such as excellent mechanical properties and superior uniformity. Therefore, developing sea squirt-based antibacterial membranes as a green food packaging film with a complete life cycle is not only crucial for the high-value development of marine biomass resources and the acquisition of high-performance food packaging materials, but also of great significance for promoting the realization of my country's "dual-carbon" strategic goals.

[0018] This invention utilizes marine fouling organisms, specifically sea squirts, to prepare a collagen-based antibacterial film, solving the problem of marine biological pollution caused by sea squirts and simultaneously achieving high-value utilization of biomass resources. From raw material selection to processing and preparation, and finally to post-use disposal, the collagen-based antibacterial film of this invention aligns with the concept of sustainable development, making it a green food packaging film with a complete lifecycle. Attached Figure Description

[0019] Figure 1 This is a scanning electron microscope image of the surface of the sea squirt collagen-based antibacterial membrane.

[0020] Figure 2 This refers to the change in malondialdehyde content in strawberries during the exposure of the sea squirt collagen-based antibacterial film to air. Implementation Example 1

[0021] A method for preparing a green, life-cycle-oriented sea squirt collagen-based antibacterial membrane includes the following steps:

[0022] (1) First, remove the shell and viscera of the sea squirt, chop it, add 5 times the volume (v / v) of 1 mol / L sodium chloride solution, let it stand at 4 ℃ for 9 h, and then rinse it with deionized water. Then add 5 times the volume of 5 mg / mL urea solution, and process it once with a high-speed homogenizer at 10000 r / min for 1 min each time. Place the homogenized mixture in a freezer and freeze for 3 h. After taking it out, thaw it slightly, and immediately stir it once with a homogenizer at 10000 r / min for 1 min each time. Repeat the "freeze-thaw-homogenize" process once. Then pour the homogenized solution into a vacuum filter to filter it into a membrane. After peeling off the membrane, rinse it repeatedly with distilled water. After completion, place it in a constant temperature and humidity chamber (humidity 80%, temperature 15 ℃) and dry it for 1 h to obtain a collagen membrane.

[0023] (2) Prepare a 1% (w / v) chitosan solution: Disperse 0.5 g of low molecular weight chitosan powder in 50 mL of 1% (v / v) acetic acid solution and stir gently at room temperature until completely dissolved.

[0024] (3) The prepared collagen membrane was soaked in chitosan solution for 2 seconds and then removed and dried naturally at room temperature to obtain sea squirt collagen-based antibacterial membrane. Example 2

[0025] A method for preparing a green, life-cycle-oriented sea squirt collagen-based antibacterial membrane includes the following steps:

[0026] (1) First, remove the shell and viscera of the sea squirt, chop it, add 10 times the volume (v / v) of 2 mol / L sodium chloride solution, let it stand at 4 ℃ for 12 h, and then rinse it with deionized water. Then add 10 times the volume of 10 mg / mL urea solution, and process it twice with a high-speed homogenizer at 12500 r / min, each time for 2 min. Place the homogenized mixture in a freezer and freeze for 4 h. After taking it out, thaw it slightly, and immediately stir it twice with a homogenizer at 12500 r / min, each time for 2 min. After homogenization, continue to freeze it in the freezer for 4 h. Repeat the "freeze-thaw-homogenize" process twice. Then pour the homogenized solution into a vacuum filter to form a membrane. After peeling off the membrane, rinse it repeatedly with distilled water. After completion, place it in a constant temperature and humidity chamber (humidity 85%, temperature 20 ℃) ​​and dry for 2 h to obtain a collagen membrane.

[0027] (2) Prepare a 2% (w / v) chitosan solution: Disperse 1 g of low molecular weight chitosan powder in 50 mL of 1% (v / v) acetic acid solution and stir gently at room temperature until completely dissolved.

[0028] (3) The prepared collagen membrane was soaked in chitosan solution for 2 seconds and then removed and dried naturally at room temperature to obtain sea squirt collagen-based antibacterial membrane. Example 3

[0029] A method for preparing a green, life-cycle-oriented sea squirt collagen-based antibacterial membrane includes the following steps:

[0030] (1) First, remove the shell and viscera of the sea squirt, chop it, add 15 times the volume (v / v) of 3 mol / L sodium chloride solution, let it stand at 4 ℃ for 15 h, and then rinse it with deionized water. Then add 15 times the volume of urea solution with a concentration of 20 mg / mL, and process it three times with a high-speed homogenizer at 15000 r / min, each time for 3 min. Place the homogenized mixture in a refrigerator and freeze for 5 h. After taking it out, thaw it slightly, and immediately stir it three times with a homogenizer at 15000 r / min, each time for 3 min. After homogenization, continue to freeze it in a refrigerator for 6 h. Repeat the "freeze-thaw-homogenize" process three times. Then pour the homogenized solution into a vacuum filtration device to filter it into a membrane. After peeling off the membrane, rinse it repeatedly with distilled water. After completion, place it in a constant temperature and humidity chamber (humidity 90%, temperature 25 ℃) and dry for 3 h to obtain a collagen membrane.

[0031] (2) Prepare a 3% (w / v) chitosan solution: Disperse 1.5 g of low molecular weight chitosan powder in 50 mL of 1% (v / v) acetic acid solution and stir gently at room temperature until completely dissolved.

[0032] (3) The prepared collagen membrane was soaked in chitosan solution for 2 seconds and then removed and dried naturally at room temperature to obtain sea squirt collagen-based antibacterial membrane. Example 4

[0033] Preservation experiment of sea tunic collagen antibacterial film.

[0034] Fresh strawberries were purchased from a local supermarket. Before the experiment, the strawberries were washed with deionized water, and the surface moisture was absorbed with filter paper. They were then irradiated under a UV lamp for 5 minutes. Strawberries without mechanical damage or pests were placed in containers. One group of containers was left untreated (control group); the other group had its containers covered with a sea squirt collagen-based antibacterial film (experimental group). Both groups of strawberries were observed at room temperature, and the malondialdehyde (MDA) content inside the strawberries was recorded.

[0035] Figure 1 This is a scanning electron microscope image of the sea squirt collagen-based antibacterial membrane, which shows that the surface of the membrane is very dense and smooth.

[0036] Figure 2 This graph shows the changes in malondialdehyde (MDA) content in strawberries during a preservation experiment. The changes in MDA content during this experiment can be used to determine the freshness of the strawberries. Figure 2 The results show that the antibacterial membrane based on sea squirt collagen and chitosan significantly reduced the changes in malondialdehyde content in strawberries. The sea squirt collagen-based antibacterial membrane exhibits excellent physical properties.

Claims

1. A method for preparing a green, full-lifecycle sea squirt collagen-based antibacterial membrane, characterized in that, Includes the following steps: 1) Preparation of collagen membrane: ① After removing the shell and viscera of the sea squirt, chop it up, add 5-15 times the volume of 1-3 mol / L sodium chloride solution, let it stand at 0-4 ℃ for 9-15 h, rinse it with water, and then add 5-15 times the volume of urea solution with a concentration of 5-20 mg / mL. ② Use a high-speed homogenizer to stir 1-3 times, 1-3 minutes each time; ③ After homogenization, place the mixture in a freezer and freeze for 3-5 hours. After thawing slightly, immediately stir it with a high-speed homogenizer 1-3 times, 1-3 minutes each time. ④ Repeat step ③ 1-2 times; ⑤ Pour the homogenized liquid into a vacuum filtration device to form a membrane. After filtration, peel off the membrane and wash it repeatedly with water to remove urea. Place the washed membrane in a constant temperature and humidity chamber with a humidity of 80-90% and a temperature of 15-25℃ to dry for 1-3 hours to obtain a collagen membrane. 2) Preparation of collagen-based antibacterial membrane: Immerse the collagen membrane in a 1-3% heated chitosan solution for 1-3 seconds, then remove it and dry it at room temperature to obtain the collagen-based antibacterial membrane.

2. The method for preparing a green, full-lifecycle sea squirt collagen-based antibacterial membrane according to claim 1, characterized in that, The rotational speed of the high-speed homogenizer is 10000-15000 r / min.

3. A sea squirt collagen-based antibacterial membrane obtained by the preparation method according to claim 1 or 2.

Images