760 results about "Food preservation" patented technology

The invention relates to a food fresh-keeping method, device and equipment and a storage medium, and the method comprises the steps: collecting respiration intensity data and decay gas concentration of target food in a cold chain carriage, carrying out fresh-keeping threshold matching, and generating food fresh-keeping information; real-time environment parameters of the cold chain compartment are collected, a fresh-keeping instruction is generated according to the food fresh-keeping information and the real-time environment parameters, and an air adjusting valve opening instruction and a compressor frequency instruction are obtained; dynamic regulation and control operation is executed based on the air regulating valve opening instruction and the compressor frequency instruction, and putrefying bacterium comprehensive evaluation indexes and compressor power consumption data are obtained in real time; and according to the putrefying bacterium comprehensive evaluation index and the compressor power consumption data, instruction feedback analysis is carried out, strategy construction is carried out, and a fresh-keeping regulation and control strategy is output. The air conditioning and refrigeration strategy can be dynamically adjusted according to the breathing characteristics of different foods and the growth dynamic state of putrefying bacteria.

The invention belongs to the technical field of functional Pickering emulsion preparation, and particularly discloses a silk fibroin nanoparticle-stabilized biphase drug-loaded Pickering emulsion and an antibacterial application thereof. The curcumin-loaded silk fibroin nanoparticles Cur-SFNPs with uniform form and size are prepared by using an anti-solvent precipitation method. In order to improve the antibacterial effect of the Pickering emulsion, the Cur-SFNPs is utilized to stabilize the soybean oil loaded with resveratrol, and the oil-in-water type Pickering emulsion is prepared. The Pickering emulsion prepared by taking Cur-SFNPs as a stabilizer has the characteristics of small particle size, uniform distribution, storage stability, heating stability, freeze-thaw stability, food safety and environmental friendliness. And as a two-phase drug-loaded emulsion, two natural hydrophobic active drugs are loaded at the same time, so that the solubility and bioavailability of the emulsion can be enhanced, the loaded active substances play a synergistic antibacterial and antioxidant role, and the emulsion can be applied to food preservation.

The invention belongs to the technical field of food preservation, and particularly relates to a field intensity adjusting method based on electrostatic preservation. According to the method, a dynamic field intensity adjusting instruction is generated by obtaining biological impedance data of a to-be-preserved object, the phase difference and the voltage amplitude of the multi-electrode plate array are controlled to form a three-dimensional rotating electric field, and space uniform distribution of field intensity is achieved. The ozone generation module operates independently of an electric field, and the ozone concentration is dynamically adjusted through an ultraviolet light source. A high-frequency short-pulse mode or a low-frequency long-pulse mode is matched according to the type of the object, and the antibacterial and fresh-keeping effects are optimized. Self-adaptive field intensity adjustment is achieved through biological impedance feedback, the three-dimensional rotating electric field and ozone decoupling control are combined, the freshness retaining uniformity and safety are improved, the shelf life is prolonged, and energy consumption is reduced.

The invention discloses a preparation method of ocimum gratissimum carbon dots and application of the ocimum gratissimum carbon dots in antibacterial drugs and food preservation. The preparation method of the ocimum gratissimum carbon dots comprises the following steps: performing steam distillation on ocimum gratissimum leaves to remove essential oil, drying in the shade, and crushing; adding an alcohol solvent into the powder, extracting, filtering, concentrating and drying to obtain an alcohol extract; dispersing the alcohol extract in distilled water, and stirring and pyrolyzing on a heating table; and diluting the pyrolysis product with distilled water, centrifuging, taking supernate, filtering with a filter membrane, dialyzing, and freeze-drying to obtain the carbon dots. The obtained carbon dots have a carbon dot-vesicle coexisting structure, and the average particle size is 5.732 + / -0.5 nm. The prepared ocimum gratissimum carbon dots can be applied to preparation of antibacterial drugs, especially drugs for inhibiting the activity of bacillus cereus and listeria, and the field of food preservation, and have the advantages of being wide in raw material source, simple in preparation method, low in cost, environmentally friendly and the like.

The invention belongs to the technical field of food preservation, and particularly discloses an aerogel fiber membrane with humidity response and capable of being used for food preservation and a preparation method of the aerogel fiber membrane. The preparation method comprises the following steps: mixing a shell film-forming substance with a first solvent to obtain a shell spinning solution; mixing a core layer gel substance, a biological preservative, a cross-linking agent and a second solvent to obtain a core layer gel spinning solution; and then carrying out coaxial electrostatic spinning on the obtained shell layer spinning solution and core layer gel spinning solution at 40-60% RH to obtain the aerogel fiber membrane which has humidity response and can be used for food preservation. The core layer with the porous aerogel structure is prepared in one step, preparation is simple, industrialization is easy to achieve, and good application prospects are achieved; the aerogel fiber membrane not only can solve the problem of juice seepage in the storage process of fresh food, but also can perform humidity response to the environment and intelligently release an antibacterial agent in a controlled mode, growth and reproduction of dominant putrefying bacteria in the storage process of the fresh food are inhibited, and the preservation period is prolonged.

The invention discloses a slow-release antibacterial and antioxidant composite preservative film and a preparation method thereof. The slow-release antibacterial and antioxidant composite preservative film is prepared from a chitosan matrix and Chuzhou chrysanthemum essential oil nano-emulsion loaded in the chitosan matrix, the Chuzhou chrysanthemum essential oil nano-emulsion comprises Chuzhou chrysanthemum essential oil, a surfactant and a cosurfactant, and the average particle size of the Chuzhou chrysanthemum essential oil nano-emulsion is smaller than 200 nm; the composite preservative film has the function of slowly releasing the Chuzhou chrysanthemum essential oil and shows antibacterial and antioxidant activity; the preparation method comprises the following steps: firstly preparing Chuzhou chrysanthemum essential oil into a nano-emulsion by adopting a nano-encapsulation method through a high-pressure homogenization method to form the Chuzhou chrysanthemum essential oil nano-emulsion, then embedding the Chuzhou chrysanthemum essential oil nano-emulsion into chitosan to prepare an active chitosan composite film, and finally applying the antibacterial coating material to food preservation. The antibacterial coating film not only can effectively inhibit pathogenic microorganism infection in berry storage and logistics transportation in a wider spectrum, but also can regulate physiological metabolism of picked berries, delay the senescence process and reduce loss of internal moisture.

The invention relates to an electric field regulation and control preservation method and device for a ship partner refrigeration house and a storage medium, and relates to the technical field of refrigeration house preservation based on an electric field, and the method comprises the steps that S1, a set working mode is received; s2, searching a corresponding electric field intensity reference value and an electric field uniformity threshold value according to a set working mode; s3, acquiring each electric field intensity sensor in real time; s4, the maximum electric field intensity error and the average electric field change rate are calculated based on the collected electric field intensity values, and comprehensive uniformity parameters are obtained through calculation in combination with the electric field intensity reference value; s5, judging whether the comprehensive uniformity parameter is lower than an electric field uniformity threshold value or not, and if yes, executing the step S6; and S6, working parameters of the electric field generator are adjusted according to the maximum electric field intensity error and the average electric field change rate. Compared with the prior art, the food fresh-keeping device can effectively solve the problem that the food fresh-keeping effect is poor due to uneven electric field distribution caused by long-term wave swinging.

The invention provides a long-acting antibacterial / antioxidant biomass-based essential oil microcapsule and a preparation method thereof. The preparation method comprises the following steps: firstly, uniformly stirring and mixing a chitosan stock solution and a casein stock solution, adjusting the pH value of a mixed system, and promoting the formation of nanoparticles through reverse charge neutralization of casein and chitosan; centrifuging the mixed solution, collecting a supernatant, slowly dripping essential oil into the supernatant, stirring and emulsifying, and ultrasonically preparing an emulsion; and finally, adding a natural cross-linking agent for cross-linking, and filtering and drying after reaction to obtain the long-acting antibacterial / antioxidant biomass-based essential oil capsule. The method does not need an additional emulsifier, is simple in process and low in cost, and is suitable for the fields of drug delivery, cosmetics and food preservation. The prepared microcapsule has the advantages of better stability, high coating rate, good slow release performance, long-acting antibacterial / antioxidant property and the like.

The invention discloses a chitosan-based preservative film with a pH colorimetric function as well as a preparation method and application of the chitosan-based preservative film. The chitosan-based preservative film is prepared from the following preparation raw materials: chitosan, cellulose nanofibers, a deep eutectic solvent and a beet red-zinc ion complex. Wherein the chitosan enables the film to have antibacterial property; the cellulose nanofiber can enhance the tensile strength and toughness and reduce the water vapor / oxygen permeation coefficient; the beet red-zinc ion complex has the characteristic of more stable color development, and the color difference response delta E to pH 2-12 is greater than or equal to 8. The chitosan-based preservative film disclosed by the invention can be applied to food fresh-keeping packaging and food freshness monitoring; the preservative film disclosed by the invention can be used for effectively prolonging the service life of fruits and vegetables while ensuring the food safety; in food freshness monitoring application, the preservative film changes from low-pH-value orange to high-pH-value yellow according to the change of acid-base conditions, and the preservative film can be used as a pH colorimetric sensing film for freshness monitoring.

The invention belongs to the technical field of high polymer materials, and particularly relates to a high-strength plastic film and a preparation method thereof. The high-strength plastic film is prepared from the following raw materials in parts by weight: 80 to 90 parts of polylactic acid, 5 to 10 parts of polyurethane resin, 2 to 6 parts of flame-retardant modified halloysite, 2 to 6 parts of antioxidant modified halloysite, 0.5 to 2 parts of silane coupling agent and 1 to 3 parts of plasticizer. According to the invention, the halloysite is subjected to flame-retardant modification and antioxidant modification and is added into a PLA matrix, so that the halloysite can be used as an inorganic filler to reinforce the rigidity and strength of the PLA matrix, and also has flame-retardant and antioxidant dual functions; meanwhile, the tubular structure of the halloysite nanotube can form a zigzag path in a PLA matrix, so that diffusion of water vapor and oxygen is delayed, the water vapor permeation amount and the oxygen permeation coefficient are reduced, and the halloysite nanotube can be applied to food packaging to prolong the fresh-keeping period of food.

The invention discloses a carbon quantum dot-polyvinyl alcohol composite film and a preparation method thereof, and belongs to the technical field of food packaging fresh-keeping materials. The composite film is prepared by taking apocynum venetum carbon quantum dots and polyvinyl alcohol as raw materials under the action of a plasticizer, wherein the apocynum venetum carbon quantum dots are prepared from apocynum venetum fiber powder, dithiosalicylic acid and urea through a hydrothermal method. The composite film provided by the invention has excellent ultraviolet shielding, pH-responsive fluorescence discoloration, antibacterial and antioxidant properties, and can realize visual monitoring of the freshness of high-protein food. The preparation method disclosed by the invention is simple in process, environment-friendly, suitable for the field of food active packaging and wide in application prospect.

The invention discloses a degradable antibacterial preservative film with medicinal and edible extracts as well as a preparation method and application of the degradable antibacterial preservative film, and belongs to the technical field of preservative films. The method comprises the following steps: (1) dissolving chitosan in an acetic acid aqueous solution, adding a wormwood extract into the obtained chitosan solution, and stirring at a certain temperature to form a mixed solution; (2) adding potato starch into water to prepare a potato starch solution; gelatinizing the potato starch solution, adding glycerol into the gelatinized solution at a certain temperature, and stirring to obtain potato starch gelatinized solution; (3) mixing the mixed solution and the potato starch gelatinization solution according to a certain proportion, pouring the mixture to a polytetrafluoroethylene substrate, and drying to form a film, so as to obtain the degradable antibacterial preservative film. The method has the advantages of being convenient in process, wide in raw material source and suitable for large-scale production. The prepared degradable antibacterial preservative film has excellent biodegradability, preservation performance and oxidation resistance, and has a wide application prospect in the field of food preservation.

The present invention belongs to the field of biotechnology and pharmaceutical engineering technology, and discloses a functionalized drug-loaded exosome based on milk exosomes, a preparation method thereof, and an application thereof. The functionalized drug-loaded exosomes include a carrier and a water-insoluble drug, and the water-insoluble drug is loaded inside the carrier; wherein the surface of the carrier is loaded with milk exosomes with functionalized molecules, and the functionalized molecule is any one of phosphatidylserine, a molecule capable of macrophage targeting, and a molecule or polymer that enhances the targeting and stability of milk exosomes; the water-insoluble drug is any one of an antibacterial drug, an antitumor drug, and a gene drug. The functionalized drug-loaded exosomes in the present invention can improve the gastrointestinal stability of oral administration and enhance the efficacy against bacterial pathogens; expand the application scope of milk exosomes in the fields of anti-intestinal bacterial infection and food preservation, and the exosome content in milk is very rich, which is convenient for large-scale preparation and has important application value.

The utility model belongs to the technical field of food preservation, and particularly relates to an alcohol bag for food preservation. The alcohol fresh-keeping material comprises a front-side wrapping material, a back-side wrapping material and an alcohol fresh-keeping material body, a middle reserved cavity is formed by the front-side wrapping material and the back-side wrapping material in a peripheral hot-pressing mode, and the middle reserved cavity is filled with an alcohol fresh-keeping material body. The surface of the front surface wrapping material is provided with breathable micropores. Ventilation micropores are formed in the back surface wrapping material. The ventilation micropores are conical holes, and the taper can be adjusted so as to assist in controlling the volatilization speed of the alcohol. Each of the front-side wrapping material and the back-side wrapping material is composed of a high-temperature-resistant printing layer, a composite connecting layer and a heat sealing layer. The alcohol fresh-keeping material body is a pure liquid or a colloidal mixture or particles. The packaging film formed by extruding macromolecules ensures that the packaging film is air-permeable and liquid-impermeable, the volatilization speed is adjustable, the situation that the taste of food is affected by overhigh local alcohol concentration is not easily caused, and meanwhile, the food can be kept fresh for a long time.

The invention relates to the technical field of papermaking, in particular to food waterproof and oilproof paper and a preparation method thereof.The food waterproof and oilproof paper is composed of base paper and a coating layer covering the surface of the base paper; the base paper is prepared from the following raw materials: sisal fibers, polylactic acid fibers, water glass, nano silicon dioxide, starch and polyacrylamide; preparing a coating layer: coating the surface of base paper with the coating liquid, and then drying and calendering to obtain the coating layer; the coating liquid is prepared from the following raw materials: modified fucoidin, poly (butylene succinate), modified nano cellulose, sorbitol, polysilicate aluminum sulfate, polyvinyl alcohol, sodium thiosulfate and water. Through matching and combination of the raw materials, the food waterproof and oil-proof paper has certain antibacterial property and strength while improving waterproof and oil-proof properties, and the food fresh-keeping effect is improved.

The invention discloses a polypropylene compounded and plasticized antibacterial starch composite material as well as a preparation method and application thereof, belongs to the technical field of food preservation, and provides the polypropylene compounded and plasticized antibacterial starch composite material. Comprising the following raw materials: 70 to 200 parts of polypropylene, 20 to 60 parts of maleic anhydride grafted polyolefin elastomer, 6.633 to 19.71 parts of starch, 2.673 to 8.91 parts of glycerin, 0.02 to 3 parts of a bacteriostatic agent and 1 part of an antioxidant. The plasticized antibacterial starch and the maleic anhydride grafted polyolefin elastomer are compounded with the polypropylene, so that the mechanical property of the polypropylene material is improved, the broad-spectrum antibacterial property of the polypropylene material is realized, and the polypropylene compounded plasticized antibacterial starch composite material effectively reduces the food transportation loss and the quality safety problem; the problem of excess production value of common polypropylene is solved, and a new choice is provided for toughening modification and antibacterial functionalization of polypropylene.

The invention provides a fresh-cut jack fruit shelf life prediction method based on characteristic metabolites, relates to the technical field of food preservation, and solves the problems that the existing shelf life prediction method depends on subjective evaluation or single physicochemical indexes, so that the precision is insufficient, and environmental parameters cannot be dynamically integrated. The method comprises the following steps: detecting metabolite components of fruit bracts with different freshness through liquid nitrogen grinding in combination with an HS-SPME / GC-MS technology, and screening a VIP value gt by using an OPLS-DA model; a BP neural network model is constructed, the concentration of the metabolites and storage parameters are input, the shelf life is predicted, and the model is verified and corrected by comparing a predicted value with an actual value. According to the method, the warehouse logistics strategy can be dynamically optimized, and the quality loss of the fresh-cut jackfruits is reduced.

The invention belongs to the technical field of food preservation, and particularly relates to a fresh meat preservation method by coupling an electric field with storage temperature, which is used for solving the problems of short preservation period, quality reduction and the like caused by microorganism breeding, oxidative deterioration and juice loss in the traditional fresh meat storage. The method comprises the following steps: cutting fresh meat into meat blocks with the thickness of 3cm-5cm, pre-cooling to 0-4 DEG C, then treating for 10-15 minutes by using an alternating electric field of 3kV / m-5kV / m, and reversing the direction of the electric field once every 30 seconds; storing the treated meat blocks in a single layer in a storage room at-1 DEG C to-1 DEG C, synchronously applying a pulsed electric field, and performing atomization sterilization every 24 hours; in the final packaging process, a packaging bag with the oxygen transmission rate smaller than 8 cm / (m.24h. 0.1 MPa) is adopted, and mixed gas of nitrogen, carbon dioxide and oxygen is inflated. The method can prolong the shelf life of fresh meat and maintain color and taste, and is suitable for industrial production.

The invention discloses preparation and application of bacteriophage-loaded sericin microgel, and belongs to the technical field of food preservation. The sericin microgel capable of loading the bacteriophage is prepared from a sericin solution extracted by using 1-ethyl-(3-dimethylaminopropyl) carbodiimide (EDC) in combination with a mechanical shearing method and a high-temperature and high-pressure method. The sericin protein microgel loaded with bacteriophage, which is obtained by soaking the microgel into bacteriophage proliferation liquid after freeze-drying, can significantly improve the storage stability of the bacteriophage and can effectively prolong the shelf life of beef, and the preparation method is green, simple and safe, has a wide application prospect, and is suitable for industrial production. Meanwhile, a new field is opened up for efficient application of the bacteriophage.

A container for a food product is disclosed, the container comprising a base and an inlay core. The base includes a base plate and a peripheral bead having an inner side wall extending upwardly from a periphery of the base plate, a top wall extending laterally outwardly from an upper end of the inner side wall, and an outer side wall extending downwardly from a laterally outer edge of the top wall. At least the lower portion of the inner side wall and the base plate laterally and from below enclose the liquid collection reservoir. The base includes a base peripheral engagement surface extending around the collection reservoir. The insert core includes a support plate having an insert core peripheral engagement surface releasably interlockable with the base peripheral engagement surface to assemble the insert core onto the base such that the support plate covers the collection reservoir. The support plate has at least one aperture for discharging liquid from above into the collection reservoir.

The invention relates to the technical field of biological preservation, in particular to a refrigerator food material preservation method and system based on a multi-modal decision dynamic weight mechanism, and the method comprises the steps: collecting multi-modal characteristic data of food materials; constructing a dynamic weight attention mechanism, and dynamically adjusting the fusion weight of each modal feature; combining a GNN graph neural network to construct a food material spoilage correlation graph, and outputting a spoilage risk prediction value at a t moment; an optimal fresh-keeping strategy combination is generated through multi-objective optimization; and processing real-time disturbance by adopting a model predictive control method and outputting a cooperative control signal. According to the method, the dynamic weight attention mechanism based on the food material category and the storage state is constructed to realize adaptive weight fusion of temperature, humidity, gas, weight and vision sensor modalities, so that the time sequence adaptability, the category specificity and the response sensitivity of multi-modal fusion are improved; and the contribution degree of the key sensor can be adaptively enhanced by the system in different scenes, and the corruption risk prediction precision is remarkably improved.

The invention discloses a chitosan grafted tannic acid-iron composite coating solution based on mussel adhesion simulation and application of the chitosan grafted tannic acid-iron composite coating solution in mango preservation, and belongs to the technical field of food preservation. According to the method, tannic acid is grafted to chitosan through a free radical mediation method to form a compound, then ferric ions are added for crosslinking, and a composite coating film with mussel adhesion imitating characteristics is constructed. According to the method, the technical problems that a traditional chitosan coating film is poor in adhesion, low in polyphenol utilization rate and prone to failure in a high-humidity environment are solved, the shelf life of mangoes can be effectively prolonged, the postharvest loss is reduced, and the method has important industrial application value.

The present invention belongs to the field of natural compounds, and specifically relates to a crude extract of frog follicles, the VMO1 protein, and their extraction methods and uses. The specific technical solution is as follows: A crude extract, wherein the crude extract is from frog follicles and does not contain egg grains. The preparation method includes: extracting the follicles of frogs, removing the egg grains under a sterile environment, adding a buffer solution, performing ultrasonic treatment and centrifugation, taking the supernatant, and filtering to obtain the crude extract. The crude extract obtained by the present invention has good maintained activity and can be further developed for subsequent uses. The crude extract obtained by the present invention can significantly reduce the surface tension, and at the same time has good antioxidant activity and good antibacterial ability, such as the ability to inhibit Pseudomonas aeruginosa. Since products derived from natural products have good biocompatibility, therefore, based on the above activities and functions, the crude extract provided by the present invention has good application prospects in multiple fields such as the field of cosmetics water retention, the field of food preservation, and the field of pharmaceuticals.

The invention relates to the technical field of food preservation, in particular to a double-layer fiber membrane for food preservation and a preparation method and application of the double-layer fiber membrane. The first layer of the double-layer fiber membrane for food preservation is composed of sericin / pullulan, and the second layer is a polylactic acid-based membrane doped with FA-coated Ag-ZIF-8 nanoparticles. The double-layer fiber membrane realizes high selectivity to oxygen and carbon dioxide, realizes regulation and control of microenvironment gas atmosphere, and inhibits respiration, so that an excellent fresh-keeping effect is achieved. The double-layer fiber membrane has antibacterial and antioxidant functions, and can inhibit oxidative degradation and microbial contamination of perishable fruits. According to the technology, dual mechanisms of gas regulation and control and biological protection are integrated, an innovative scheme is provided for solving the rotting problem of perishable fruits, and the technology shows important potential in the aspects of promoting development of a food fresh-keeping technology and optimizing a sustainable packaging scheme.

1. The name of the design product: Fresh-keeping box (3). 2. The use of the design product: used for food preservation. 3. The design points of the design product: in shape. 4. The picture or photo that best shows the design points: Design 1 perspective view. 5. Design 1 is designated as the basic design.

The invention provides an adsorbent with antioxidant and moisture absorption effects and a preparation method thereof. The preparation method comprises the following steps: preparing an emulsion, preparing a gelatin solution, preparing sol, preparing aerogel, and loading the curcumin emulsion to the aerogel. A cross-linked network of chitosan and gelatin can be used as a slow-release carrier of curcumin, curcumin is prepared into an oil-in-water emulsion and then is loaded by aerogel, after the aerogel absorbs water, the oil-in-water emulsion is easier to release, volatile oil is used as an oil phase of the emulsion, and curcumin can be carried to volatilize, so that the antibacterial and antioxidant effects are better exerted. The prepared adsorbent has excellent hygroscopicity, oxidation resistance and chemical stability, and has wide application prospects in the fields of food preservation and the like.

The invention belongs to the technical field of food fresh-keeping and antibacterial materials, and discloses a preparation method and application of a bamboo cellulose-based sprayable hydrogel fresh-keeping film. According to the system, bamboo cellulose is used as a structural support and cooperates with epsilon-polylysine and bamboo polyphenol, and a hydrogel coating with physical barrier, antibacterial and antioxidant functions is formed on the surfaces of fruits and vegetables through in-situ self-assembly and calcium ion crosslinking. The method comprises the following steps: compounding sodium alginate, carboxymethyl chitosan and a bamboo fiber nano dispersion liquid, and adding epsilon-polylysine and bamboo polyphenol to prepare a functional spray; a calcium chloride solution is sprayed after spraying, and a stable and transparent hydrogel film with high adhesive force is rapidly formed through ionic crosslinking. The technical process is simple and convenient, the film forming speed is high, the components are natural, and industrial spraying is easy. Verified by fruits and vegetables such as bananas and the like, the coating can effectively delay decay, and the application blank of the nano bamboo cellulose in a spray fresh-keeping carrier is filled.

The invention aims to provide a preparation method and application of a CMC / PVA active packaging film coated with chitosan-tannic acid on the surface, and belongs to the field of food preservation. Comprising the following steps: firstly, preparing a CP40 film, and then preparing a CP40 / CT% composite film: preparing a chitosan solution with the mass concentration of 1%, adding tannic acid TA into the chitosan solution, stirring for 30 minutes in a shading manner at room temperature to form a CT coating solution, flatly laying the prepared CP40 film on a planar carrier, coating the surface of a substrate film with the CT coating solution, and putting the composite film and the carrier into a drying oven at 45 DEG C for constant-temperature drying, so as to obtain the CP40 / CT% composite film. And after the solvent of the coating layer is completely volatilized, taking out and stripping to obtain the CP40 / CT% composite film. Under the action of hydrogen bonds and electrostatic attraction, a compact network structure of an amorphous-weak crystal region is formed in the composite film, so that the interface bonding strength of the film is enhanced, and the rigidity and flexibility of the film are balanced. The physical and chemical properties and biological activity of the composite membrane are synergistically optimized, and the composite membrane has obvious degradation signs after being buried in soil for 35 days and belongs to a biodegradable material.

The application discloses a pH-responsive degradable composite bacteriostatic film derived from waste bone powder extract and a preparation method thereof. The main components of the film are collagen and hydroxyapatite extracted from waste bone powder, citric acid monohydrate-betaine and lactic acid-betaine eutectic solvent, and in addition, purple corn anthocyanin is used as a pH response agent, and citric acid monohydrate-betaine eutectic solvent is used as a crosslinking agent and a bacteriostatic agent. In the preparation process, collagen and hydroxyapatite are mixed with an aqueous solution of eutectic solvent and heated, and after the system is reduced to room temperature, the anthocyanin aqueous solution is added, mixed, and ultrasonic defoaming is performed, then the film forming liquid is poured into a clean mold, vacuum dried, and cooled to remove the film. The pH-responsive degradable composite film prepared based on the above method has good properties, not only has the characteristics that the overall color changes with the microenvironment pH, but also has good mechanical strength, bacteriostasis and degradability, and has wide application potential in many fields such as food preservation.

The utility model relates to the technical field of vacuum packaging machines, and discloses a vacuum packaging machine for food preservation, which comprises a machine body, a packaging groove is arranged at the top of the machine body, a partition plate is fixedly mounted at the top of the packaging groove, and two fixing plates are fixedly mounted on each of the left side and the right side of the partition plate. Sliding columns are slidably mounted in the left end and the right end of the fixing plate. Through the arrangement of the fixing plate, when a packaging bag is placed on the top of the pressing block and the top of the fixing plate, the fixing rod is rotated firstly to press the packaging bag preliminarily, and when the vacuum compressor presses the pressing rod downwards, the pressing rod compresses the spring through the attraction force of the magnet; the situation that due to different shapes of food, deviation occurs during vacuum packaging operation is avoided, the position of the packaging bag is further reinforced through magnetic attraction between the magnet and the fixing plate, and the situation that due to the fact that the food shape is irregular or internal air pressure changes, the packaging bag deviates or deforms is effectively prevented; therefore, the consistency and the attractiveness of the packaging quality are ensured.