JP2020500792A - Packaging material and its preparation method - Google Patents

Abstract

A packaging material is provided. The packaging material includes a degradable polymer and a natural antimicrobial agent, wherein the degradable polymer forms a polymeric matrix in which the natural antimicrobial agent is dispersed. Also provided are methods of preparing the packaging material, and the use of the packaging material in food packaging. There are no drawings relating to the publication of the abstract.

Description

[Cross-reference of related applications]
This application claims the benefit of priority of Singapore Patent Application No. 10201610373X, filed December 9, 2016, the contents of which are hereby incorporated by reference in their entirety for all purposes. Be incorporated.

  Various embodiments relate generally to materials and methods, and more particularly to materials and methods for packaging applications, such as packaging materials used in food technology.

  Currently, about 40 million tonnes of plastic packaging is used annually around the world, and its food and beverage packaging contributes an estimated 70% of the United States (US) packaging market of over $ 100 billion, and $ 400 billion. Contributes to more than half of the world market. The increased indiscriminate use of non-degradable polymers for food packaging applications is causing serious ecological problems due to their non-degradability and increasing environmental concerns regarding their disposal Has been brought.

  Landfill and incineration are the first methods used in the disposal of these plastic wastes. However, there are limitations associated with these waste disposal methods. For example, landfills are not long-term sustainable because non-degradable polymers remain in the environment even after very long periods of time. As a result, city planners are constantly faced with the pressure to procure more land space for landfills. On the one hand, burning plastic in incinerators produces toxic by-products that pollute the environment. Physical reuse of plastic packaging is often impractical and economically inconvenient due to contamination by food and biological materials.

  Global concerns about the environmental impacts caused by the widespread use of polymeric materials are driving more attention to the development of environmentally friendly degradable polymers for food packaging applications. The use of macromolecules with completely degradable properties serves as a decisive step in protecting society from ever-increasing environmental pollution.

  In addition to the above, another important consideration in selecting a filling material for food packaging relates to the ability of the packaging material to maintain food safety and quality throughout storage, transport, and end use. Toxic residues and corrosive solvents left behind during the manufacturing process can cause food spoilage and are detrimental to food safety. At the same time, raw and processed product contamination, especially those caused by cold pathogens and spoilage microorganisms, has always been a serious concern to human health.

  One conventional method of reducing and inhibiting microbial growth is to use dipping or spraying an antimicrobial agent on the surface of the product. However, antimicrobial substances, if evaporated and diffused into the bulk of the food product, can interact with the components of the food product with minimal success.

  Other approaches have also been used to extend the storage of environmentally friendly products. These include high hydrostatic pressure, high intensity ultrasound, and gamma irradiation. However, these treatments have been of limited success because they can affect the sensory properties of the food, alter the structure of the protein in the food, and generate free radicals that affect the aroma of the food.

  The use of films containing synthetic preservatives that inhibit the growth of food spoilage microorganisms represents a possible solution to increase food safety and extend the shelf life of the food, but consumers have found that synthetic Concerns have been raised over the safety of foods in direct contact with preservatives, and there is debate about the use of chemical additives in foods.

  Despite various preservation methods, foodborne infections in the US are increasing over time, causing approximately 76 million patients, 325,000 hospitalizations, and 5000 deaths annually, It has been estimated that more than 5.2 million cases are due to food-borne bacterial pathogens. As a result, consumers are demanding that packaging materials be made from environmentally friendly, degradable materials while avoiding the use of chemical preservatives and improving food preservation.

  Therefore, there is a demand for the development of a new packaging system that produces an environmentally friendly food packaging film with an environmentally friendly manufacturing process. It can have degradability in the natural environment to increase food safety and extend the shelf life of food, while providing antibacterial / antifungal properties that inhibit the growth of food spoilage microorganisms .

  In a first aspect, a packaging material is provided. The packaging material includes a degradable polymer and a natural antimicrobial agent, wherein the degradable polymer forms a polymeric matrix in which the natural antimicrobial agent is dispersed.

  In a second aspect, there is provided a method of preparing a packaging material according to the first aspect. The method includes providing a natural antimicrobial agent, wherein the method provides for dispersing the natural antimicrobial agent in a degradable polymer to obtain a packaging material.

  In a third aspect, there is provided the use of the packaging material according to the first aspect or the packaging material prepared by the method according to the second aspect in food packaging.

  The present invention will be better understood with reference to the detailed description when considered in conjunction with non-limiting examples and the accompanying drawings.

FIG. 2 is a schematic diagram illustrating two-roll milling as a first step in manufacturing an environmentally friendly packaging film according to one embodiment. In the figure, PCL means poly (ε-caprolactone).

FIG. 4 is a schematic diagram illustrating a combination of sieving and two-roll milling as a second step of manufacturing an environmentally friendly packaging film according to one embodiment. In the figure, PCL means poly (ε-caprolactone), CS means chitosan, and GFSE means grapefruit seed extract.

FIG. 4 is a schematic diagram showing a heat press as a third step of manufacturing an environmentally friendly packaging film according to one embodiment. In the figure, PCL means poly (ε-caprolactone), CS means chitosan, and GFSE means grapefruit seed extract.

It is the schematic which shows the dissolution process in manufacture of CS / GFSE particle.

It is the schematic which shows the freeze-dry process in manufacture of CS / GFSE particle.

It is the schematic which shows the accumulation process of the powder in manufacture of CS / GFSE particle.

1 is an optical image showing the overall appearance and flexibility of a PCL film as manufactured.

1 is an optical image showing the overall appearance and flexibility of a PCL / CS composite film (PCL / CS film: 15 wt% CS) during manufacture.

1 is an optical image showing the overall appearance and flexibility of a PCL / CS / GFSE composite film (PCL / CS / GFSE film: 15 wt% CS / GFSE (CS: GFSE ratio, 1: 1 g / ml)) as manufactured. .

1 is an optical image showing the overall appearance and flexibility of a manufactured CS / GFSE composite film (CS / GFSE film: 1: 1 g / ml).

1 is an optical image showing the overall appearance and flexibility of a PE film as manufactured (PE means polyethylene).

It is an optical image which shows the transparency of the PCL film at the time of manufacture.

It is an optical image which shows the transparency of the PCL / CS composite film (PCL / CS film: 15 wt% CS) at the time of manufacture.

It is an optical image which shows the transparency of the PCL / CS / GFSE composite film at the time of manufacture (PCL / CS / GFSE film: CS / GFSE of 15 wt% (CS: GFSE ratio, 1: 1 g / ml)).

It is an optical image which shows the transparency of the CS / GFSE composite film (CS / GFSE film: 1: 1 g / ml) at the time of manufacture.

It is an optical image which shows the transparency of the PE film at the time of manufacture.

Figure 4 is an optical image showing before (top) and after (bottom) sliding of a water droplet on a PCL film. The contact angle is 74.4 ± 1.4 °.

Figure 4 is an optical image showing before (top) and after (bottom) sliding of water droplets on PCL / CS composite film. The contact angle is 75.0 ± 2.7 °.

Figure 4 is an optical image showing before (top) and after (bottom) sliding of a droplet of water on a PCL / CS / GFSE composite film. The contact angle is 50.0 ± 7.8 °.

Figure 4 is an optical image showing before (top) and after (bottom) sliding of a water droplet on a PE film. The contact angle is 95.3 ± 4.6 °.

It is a scanning electron microscope (SEM) image which shows the surface morphology of a PCL / CS composite film (PCL / CS film: CS of 15 wt%). Scale bar means 50 μm.

It is a scanning electron microscope (SEM) image which shows the surface morphology of a PCL / CS composite film (PCL / CS film: CS of 15 wt%). Scale bar means 10 μm.

It is a scanning electron microscope (SEM) image which shows the cross section of PCL / CS composite film (PCL / CS film: CS of 15 wt). Scale bar means 100 μm.

It is a scanning electron microscope (SEM) image which shows the cross section of PCL / CS composite film (PCL / CS film: CS of 15 wt). Scale bar means 20 μm.

FIG. 3 is a diagram showing a Fourier transform infrared spectroscopy (FTIR) spectrum of a PCL / CS composite film (PCL / CS film: 15 wt CS) showing characteristic functional groups of PCL and CS.

FIG. 4 is a diagram showing a UV-vis spectrum of a PCL / CS composite film in comparison with a pure PCL film.

It is a figure which shows the antioxidant property of PCL / CS composite film (DPPH: 1,1- diphenyl-2-picryl hydrazyl; PCL / CS film: CS of 15wt).

FIG. 3 is a diagram showing a decomposition profile of a PCL / CS composite film (PCL / CS film: 15 wt% CS) in seawater, as compared to a pure PCL film.

FIG. 2 is an optical image showing a preliminary study of fungal growth in bread samples filled with PE, PCL, PCL / CS and PCL / CS / GFSE films and stored at 24 ° C. for up to 13 days (control group: commercial foods). Packaging polyethylene (PE) film and pure PCL film; PCL / CS film: 15 wt% CS; PCL / CS / GFSE film: 15 wt% CS / GFSE (CS: GFSE ratio: 1: 1 g / ml); dark arrow : First fungal growth).

  Packaging materials according to various embodiments disclosed herein have antimicrobial / antimycotic properties due to the presence of a natural antimicrobial agent as an additive in the packaging material. Thus, for example, in food packaging applications, to slow or inhibit the growth of food spoilage microorganisms by inhibiting the growth of undesirable microorganisms on the food surface when the packaging material comes into contact with the food. May be possible. In doing so, food safety for public health and extending the shelf life of the food may be realized. Advantageously, the packaging material according to the embodiments disclosed herein is an environmentally friendly, environmentally friendly packaging material, the preparation of which is free of chemical additives and toxic residues, It involves a process. Packaging materials according to embodiments disclosed herein may be particularly suitable as food packaging materials for various food products, such as confectionery, marine products, red meat, dairy products, to name just a few.

  With the above in mind, in a first aspect, various embodiments refer to a packaging material comprising a degradable polymer and a natural antimicrobial agent.

  As used herein, the term "packaging material" refers to a material for containing or surrounding an object, at least partially or completely. By at least partially or completely enclosing or surrounding the object, the packaging material may function as a barrier layer, or may act as an interface between the object and the environment, and contaminants or contaminants that may be present in the environment. Seals and / or protects objects from degradation and / or contamination due to Further, the packaging material may be in direct contact with the object, which may translate into a reduced rate of object degradation due to the action of the natural antimicrobial agent. In some embodiments, the packaging material can be used to form a container that can be used to hold or contain perishable items such as food.

  In various embodiments, the packaging material is a packaging film. For example, the packaging film may be in the form of a flat sheet or a continuous layer. The packaging material can be, for example, a food packaging film. In some embodiments, the packaging film is in direct contact with the food and may be used as a cling wrap, cling film, or food wrap for food packaging, or to seal the food in a container.

  The packaging film may be of sufficient thickness to provide barrier and mechanical properties and ease of processing, and may have a thickness appropriate for the intended use. For example, thick films, such as films having a thickness of 50 μm or more, have better barrier properties, but with such a film, film flexibility and transparency are compromised. On the one hand, thin films, such as films having a thickness in the range of 10 μm or in the range from about 10 μm to about 20 μm, still provide sufficient barrier and mechanical properties, but use less material. Bring.

  The packaging material includes a degradable polymer and a natural antimicrobial agent. As used herein, the term "macromolecule" refers to a large molecule made up of repeating small chemical units. The repeat unit of the polymer is usually equivalent or nearly equivalent to the monomer, ie, the starting material from which the polymer is formed. The repeating units of the polymer can be connected to each other by covalent bonds. In some cases, such as when the macromolecular chain has a single main chain without branches, the repeats are linear. In some cases, the chains are branched or interconnected to form a three-dimensional network.

  A macromolecule is a degradable macromolecule, which has a molecular structure that can break down or decay into small molecules over a period of time (eg, within days, or months, or years). Means The time required for degradation depends on factors such as the type of degradable polymer and environmental conditions. In various embodiments, the degradable polymer can degrade over a period of more than 20 years. In some embodiments, the degradable polymer can degrade over a period of 20 years or less, such as 15 years, 10 years, 8 years, 5 years, or 2 years or less. At room temperature, the degradation period of the polycaprolactone film in a dry environment can be, for example, 8 years or less. Degradation or spoilage of degradable macromolecules occurs by a variety of mechanisms, for example, by the action of naturally occurring microorganisms such as bacteria, fungi and algae, light, oxidation, and / or chemicals (such as water). obtain. The degradable polymer can thus be a biodegradable polymer, a photodegradable polymer, an oxidatively degradable polymer, and / or a hydrolyzable polymer.

  Examples of degradable polymers include, but are not limited to, glycolide, lactide, polylactic acid polymers and oligomers, polyesters of α-hydroxy acids including lactic acid and glycolic acid, polyglycolic acid, poly (DL-lactic acid) -Co-glycolic acid) (PLGA), poly-L-lactic acid (PLLA), and poly (α-hydroxy) acids, including terpolymers of DL-lactide and glycolide, with ε-caprolactone and polyester. Polylactones and polycaprolactones including polymerized ε-caprolactone, poly (caprolactone) (PCL), poly (ε-caprolactone), poly (δ-valerolactone), and poly (gamma-butyrolactone), polyanhydride, polyortho Esters, other hydroxy acids, polydioxanone and non-toxic Or as a metabolite in the body, including other biologically degradable polymer. Examples of polyamino acids include, but are not limited to, polylysine (PLL), poly L-aspartic acid, poly L-glutamic acid, and styrene-maleic anhydride copolymer. Examples of derivatives of polyethylene glycol include, but are not limited to, poly (ethylene glycol) -di- (ethylphosphatidyl (ethylene glycol)) (PEDGA), poly (ethylene glycol) -co-anhydride, poly (ethylene Glycol) -co-lactide, poly (ethylene glycol) -co-glycolide, and poly (ethylene glycol) -co-orthoester. Examples of acrylamide polymers include, but are not limited to, polyisopropylacrylamide, and polyacrylamide. Examples of acrylic acid polymers include, but are not limited to, diacrylates such as polyethylene glycol diacrylate (PEGDA), oligoacrylates, methacrylates, dimethacrylates, oligomethacrylates, and PEG-oligoglycolyl acrylates. Including. Examples of carboxyalkyl cellulose include, but are not limited to, carboxymethyl cellulose, and partially oxidized cellulose.

  In various embodiments, the degradable polymer is poly (ε-caprolactone), aliphatic polyester, polylactide, poly (glycolide), poly (hydroxyester ether), poly (hydroxybutyrate), poly (anhydride), It is selected from the group consisting of polycarbonate, poly (amino acid), poly (ethylene oxide), poly (phosphazene), polyetherester, polyesteramide, polyamide, combinations thereof, and copolymers thereof.

  In certain embodiments, the degradable polymer comprises poly (ε-caprolactone).

  The degradable polymer can have a weight average molecular weight ranging from about 60,000 to about 100,000, such as about 70,000 to about 90,000, or about 75,000 to about 85,000.

  The packaging material also contains a natural antimicrobial agent. As used herein, the term "natural" means that the substance can be found in nature. As used herein, the term "antimicrobial" refers to the ability to inhibit or suppress the spread or growth of microorganisms, which are unicellular or live in colonies of cellular organisms. Examples of microorganisms include bacteria, mycobacterium, fungi, yeast, archaebacteria, viruses, protests, or parasites. The terms "antibacterial" and "antifungal" refer to the ability of bacteria and fungi to inhibit or inhibit the spread or growth, respectively. In some embodiments, the antimicrobial is an antibacterial and / or antifungal.

  In various embodiments, the antimicrobial agent is capable of inhibiting or inhibiting the spread or growth of a microorganism selected from the group consisting of Gram positive bacteria, Gram negative bacteria, fungi, and combinations thereof.

  The term "Gram-positive bacteria" refers to bacterial cells that stain purple (positive) on a Gram stain test. Gram staining is associated with peptidoglycan abundant in the cell wall of Gram-positive bacteria. In contrast, the cell wall of "Gram-negative bacteria" is low in peptidoglycan, so that Gram-negative bacteria accept the counterstain of the Gram stain test. Bacteria include, for example, Acinetobacter, actinomycetes, Aeromonas, Bordetella, Borrelia, Brucella, Burkholderia, Campylobacter, Chlamydia, Clostridium, Corynebacterium, Enterococcus, Erwinia, Escherichia, Francisella, Hemophilus, Helicobacter, Klebsiella, Legionella , Listeria, Mycobacterium, Mycoplasma, Neisseria, Pseudomonas, Rickettsia, Salmonella, Shigella, Staphylococcus, Streptococcus, Treponema, Bayonela, Vibrio, or Yersinia. In certain embodiments, the bacterium comprises the group consisting of Staphylococcus aureus, Mycobacterium smegmatis, Pseudomonas aeruginosa, Burkholderia cepacia, Klebsiella pneumoniae, Elomonas hydrophila, Erwinia carotobola, Erwinia chrysanthe, and Escherichia coli. Is selected from

  Fungi include, for example, Candida albicans, Candida tropicalis, Candida (Crabispora) lusitania, Candida (Pichia) Giliel Mondi, Rodderomyces elongisporus, Debariomyces hanseni, Pichia stiptis, Aspergillus fumigatus, Blastmais It can be a species of dermatitidis, Cladofiarophora bantiana, Coccidioides imitis, Cryptococcus neoformans, Fusarium, Microsporum, Penicillium marnefei, or Trichophyton.

  In various embodiments, the antimicrobial agent is capable of inhibiting or inhibiting the spread or growth of a microorganism selected from the group consisting of E. coli, S. aureus, Candida, Albicans, and combinations thereof.

  Natural antimicrobial agents can be obtained from natural compounds such as, for example, weak organic acids, organic compounds, antimicrobial enzymes, bacteriocins, triclosan, fungicides, nisin, fruit and plant extracts, essential oils, and / or natural polysaccharides. Can be. In some embodiments, the natural antimicrobial agent is selected from the group consisting of chitosan, chitin, lignin, derivatives thereof, combinations thereof, and copolymers thereof. Derivatives of lignin may include, for example, lignin esters, lignin ethers, lignin hydroxyalkylates, lignin acrylates, carboxy lignins, or hydroxyalkoxy lignins.

  In certain embodiments, the natural antimicrobial agent comprises chitosan. Chitosan has good biodegradability, biocompatibility, and antimicrobial activity, which confers the utility of chitosan for biomedical applications. The term "chitosan", also referred to as poly-D-glucosamine or polyglucosamine, is a β-1,4-glycosic acid linked to glucosamine and optionally N-acetylglucosamine residue (2-acetamido-2-desoxy-). β-D-glucopyranose residue), wherein the ratio of glucosamine to N-acetylglucosamine residue is greater than 1 and refers to a chitin-derived biopolymer.

  The term "chitosan" as used herein also includes quaternized chitosan, also referred to herein as quaternary ammonium chitosan, which contains a quaternary ammonium group at the dissociated hydroxyl or amino group of chitosan. It is a derivative of chitosan prepared by introduction. As a result of quaternization of the amino group, quaternized chitosan has a permanent positive charge on the polysaccharide backbone. Due to this permanent positive charge, quaternized chitosan can also be called cationic quaternized chitosan.

  In various embodiments, chitosan is represented by Formula (I).

(I)

Each _{X, -NH-C (O) -CH} 3, -N (R 1) (R 2), and ^{-N + (R 3) (R} 4) independently selected from ^{(R 5),} where , at least one X is ^{-N + (R 3) (R} 4) (R 5), R 1, R 2, R 3, R 4 and ^{R 5} are independently from H and _{C 1-18} alkyl Let k be an integer between 3 and 3000.

The term “C ₁ -C ₁₈ alkyl” refers to a fully saturated aliphatic hydrocarbon having 1 to 18 carbon atoms. For example, it means that the alkyl group contains one carbon atom, two carbon atoms, three carbon atoms, etc., and contains up to 18 carbon atoms. The C ₁ -C ₁₈ alkyl group may be linear or branched, and may be substituted or unsubstituted. Exemplary substituents include, but are not limited to, C _1-6 aliphatic groups, hydroxy, alkoxy, cyano, halogen, nitro, silyl, and amino, and are mono- and di-substituted. Contains an amino group. Specific exemplary substituents are C ₁ -C ₁₀ alkoxy, C ₅ -C ₁₀ aryl, C ₅ -C ₁₀ aryloxy, sulfhydryl, C ₅ -C ₁₀ aryl, thio, F, Cl, Br, I Includes halogen, hydroxyl, amino, sulfonyl, nitro, cyano, and carboxyl groups. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-hexyl, n-heptyl, n-octyl, It can be n-nonyl or n-decyl and the like.

  Referring to formula (I), k is an integer from 3 to 3000. For example, k is 3 to 2800, 3 to 2400, 3 to 1800, 3 or 1600, 3 to 600, 120 to 3000, 600 to 3000, 700 to 2500, 1500 to 2500, 1200 to 2400, 1600 to 2800, or 1800 To an integer from 2800.

In various embodiments, R ¹ and R ² are selected from H and C _1-18 alkyl, and R ³ , R ⁴ , and R ⁵ are each independently C _1-10 alkyl. In certain embodiments, R ¹ and R ² are H, R ³ , R ⁴ and R ⁵ are each independently C _1-10 alkyl.

In various embodiments, R ³ and R ⁴ are methyl and R ⁵ is C _1-10 alkyl, preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl , N-octyl, n-nonyl or n-decyl. In certain embodiments, R ³ and R ⁴ are methyl and R ⁵ is methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl And n-decyl.

In various embodiments, X = —NH—C (O) —CH of a monomer where X = —N (R ¹ ) (R ² ) and —N ⁺ (R ³ ) (R ⁴ ) (R ⁵ ). _The ratio for a monomer that is ₃ is greater than 1. For example, X = ^-N (R 1) with ^{(R 2)} and ^{X = -N + (R 3)} (R 4) of ^{(R 5)} is a monomer, X = -NH-C (O ) -CH 3 The ratio for a given monomer can range from 2: 1 to 5: 1.

On the other hand, the ratio of the monomer where X = −N (R ¹ ) (R ² ) to the monomer where X = −N ⁺ (R ³ ) (R ⁴ ) (R ⁵ ) is 1: 4 to 4: 1. Range.

  Although a natural antimicrobial agent can inhibit or inhibit the spread or growth of microorganisms, in various embodiments, the natural antimicrobial agent further enhances the natural antimicrobial and / or antifungal properties of the natural antimicrobial agent. An active agent may be included.

  As used herein, the term "bioactive agent" refers to a substance that has an effect, such as a biological effect, on a living organism. As with natural antimicrobial agents, natural bioactive agents are substances that can be found in nature. In various embodiments, the natural bioactive agent comprises grapefruit seed extract, olive leaf extract, natamycin, hinokitiol, lysozyme, bacteriocin, essential oil, tea tree oil, lemon peel, pomelo, cinnamon, and combinations thereof. Selected from the group.

  In certain embodiments, the natural bioactive agent comprises or consists of a grapefruit seed extract, which refers to one or more antimicrobial components derived from a grapefruit seed, by extracting with an organic solvent. can get. The organic solvent can be, for example, an organic solvent containing one or more hydroxyl groups, such as glycol.

  Advantageously, the use of a combination of natural antimicrobial and natural bioactive agents, such as those shown in FIG. 9 (PCL / CS group vs. PCL / CS / GFSE group), enhances the effect of inhibiting microbial growth I will provide a. The ratio of natural bioactive agent to natural antimicrobial agent can be from about 1: 1 to about 3: 2 ml / g, from about 1: 1 to about 2: 1 ml / g, about 1: 1 to allow for easy production. From about 5: 2 ml / g, from about 3: 2 to about 3: 1 ml / g, from about 2: 1 to about 3: 1 ml / g, or from about 3: 2 to about 2: 1 ml / g, such as about 1: 1. To about 3: 1 ml / g.

  The degradable polymer forms a polymer matrix in which the natural antimicrobial agent is dispersed. For example, the natural antimicrobial agent can be in the form of particles. The natural antifungal agent can be at least substantially uniformly dispersed in the polymeric matrix. The term "substantially homogeneously dispersed" means that the distribution of the natural antifungal agent in the degradable polymer is substantially uniform or identical in all regions thereof, and the concentration or rate of the natural antifungal agent is It means that no special region that is substantially larger or smaller than any of its other regions is present in the degradable polymer.

  In various embodiments, the natural antimicrobial agent is about 5 μm to about 75 μm, about 10 μm to about 75 μm, about 20 μm to about 75 μm, about 30 μm to about 75 μm, about 50 μm to about 75 μm, about 5 μm to about 60 μm, about 5 μm to about 5 μm. Particles having a size of 75 μm or less, such as about 50 μm, or a size ranging from about 30 μm to about 50 μm.

  The amount of the natural antimicrobial agent in the polymeric substrate can be from about 0.01 wt% to about 35 wt%, about 0.01 wt% to about 20 wt%, about 0.01 wt% to about 15 wt%, about 1 wt% to about 25 wt%. , About 15 wt% to about 40 wt%, or about 25 wt% to about 40 wt%, such as about 0.01 wt% to about 40 wt%. In some embodiments, the amount of the natural antimicrobial agent in the polymeric matrix ranges from about 0.01 wt% to about 15 wt%, with a tensile strength similar to that exhibited by a commercial polyethylene (PE) packaging film. And ranges suitable for realizing mechanical properties, such as breaking strain.

  In a second aspect, various embodiments refer to a method of preparing a packaging material according to the first aspect. The method includes providing a natural antimicrobial agent. Suitable examples of natural antimicrobial agents have already been discussed above.

  As mentioned above, the natural antimicrobial agent may further include a natural bioactive agent. Suitable natural bioactive agents have already been mentioned above. In various embodiments, the natural bioactive agent comprises or consists of a grapefruit seed extract. Because the method does not rely on the chemical properties of the natural bioactive agent, even if the natural bioactive agent of the grapefruit seed extract is exemplified herein, advantageously the method of preparing the packaging material Is not limited to grapefruit seed extract, and may employ other types of natural bioactive agents, such as those mentioned above.

  In embodiments where the natural antimicrobial agent further comprises a natural bioactive agent, providing the natural antimicrobial agent comprises dispersing the natural antimicrobial agent and the natural bioactive agent in an aqueous solution, such as water or a buffer, to form an aqueous mixed solvent. This may include dissolving and drying the aqueous mixed solvent to obtain the natural antimicrobial agent.

  Dissolution of the natural antimicrobial agent and the natural bioactive agent in the aqueous solution can be, for example, at a ratio of the natural bioactive agent to the natural antimicrobial agent in the range of about 1: 1 to about 3: 1 ml / g, or any within that particular range. May be implemented as a suitable partial range of Advantageously, dissolution of the natural antimicrobial agent and the natural bioactive agent in the aqueous solution can be performed at ambient conditions. Substantially some or all of the natural bioactive agent and the natural antimicrobial agent can be dissolved in the aqueous solution to form an aqueous mixed solvent.

  The aqueous mixed solvent may be dried using any suitable drying method to obtain a natural antimicrobial with a natural bioactive agent. In various embodiments, drying of the aqueous mixed solvent can be performed by a two-stage method of freeze drying and vacuum drying.

  Various embodiments of the freeze-drying technology disclosed herein are based on the principle of water sublimation. During freeze-drying, the simultaneous action of vacuum and temperature may facilitate the need for hermetic filling of natural antimicrobial agents and natural bioactive agents. At the same time, the water present in the aqueous mixed solvent can sublime. In doing so, water may be removed from the aqueous mixed solvent, leaving only the natural antimicrobial agent and the natural bioactive agent, and allowing physical binding of the natural bioactive agent to the natural antimicrobial agent. Advantageously, by controlling the pressure and temperature, water can evaporate or sublime from the aqueous mixed solvent to form a natural antimicrobial with a natural bioactive agent. This makes the process environmentally friendly as no dangerous and toxic solvents are used.

  Freeze-drying the aqueous mixed solvent can be performed at any suitable temperature sufficient to sublime the water present in the mixture. In various embodiments, freeze drying of the aqueous mixed solvent is from about −30 ° C. to about 0 ° C., about −10 ° C. to about 0 ° C., about −50 ° C. to about −10 ° C., about −50 ° C. to about −20 ° C. C., from about -50.degree. C. to about -30.degree. C., from about -40.degree. C. to about -10.degree. C., from about -30.degree. C. to about -20.degree. C., and the like. In some embodiments, freeze drying of the aqueous mixed solvent is performed at a temperature of about -40 <0> C.

  Freeze drying may be performed for a time ranging from about 1 hour to about 3 hours, such as about 1.5 hours to about 2.5 hours, or about 2 hours. Subsequently, the aqueous mixed solvent that has been freeze-dried may be vacuum dried for a time ranging from about 1 day to about 3 days, such as about 1.5 days to about 2.5 days, or about 2 days.

  In various embodiments, the natural antimicrobial is in the form of particles, which may have a size of 75 μm or less.

  The methods disclosed herein include dispersing a natural antimicrobial agent in a degradable polymer. This may include melting the degradable polymer, mixing the natural antimicrobial agent with the melted degradable polymer to form a polymer mixture, and heat pressing the polymer mixture. .

  Melting the degradable polymer can be performed at a temperature above the melting point of the degradable polymer using, for example, a two-roll milling process, such as that shown in FIG. 1A. The rollers can rotate in opposite directions, and the shear forces generated by the rollers can be used to mix or disperse the material fed onto the rollers.

  The speed at which the rollers rotate can be any suitable speed, such as a speed ranging from about 2 rpm to about 10 rpm. In embodiments where the degradable polymer is poly (ε-caprolactone), melting the degradable polymer may be performed at about 65 ° C.

  The step of mixing the natural antimicrobial agent with the melted degradable polymer is performed while the two-roll milling process is being performed, such as that shown in FIG. 1B. This may include sieving the natural antimicrobial agent.

  When forming the polymer mixture, the polymer mixture, such as that shown in FIG. 1C, can be removed from the rollers and subjected to a heat press treatment. In various embodiments, heat pressing of the polymer mixture is performed at a pressure in the range of about 20 MPa to about 40 MPa, such as about 25 MPa to about 35 MPa, or about 30 Mpa. When heat-pressing the polymer mixture, the packaging material may take the form of a packaging film.

  Various embodiments are referenced in further aspects to the use of the packaging material according to the first aspect, or the packaging material prepared by the method according to the second aspect, in food packaging. Advantageously, packaging materials according to embodiments disclosed herein have sufficient UV absorption, anti-poisoning and anti-bacterial / anti-fungal functions, but are naturally degradable, suitable for optical packaging suitable as food packaging films. And demonstrate mechanical properties. The packaging materials disclosed herein degrade in the natural environment (e.g., seawater) to yield non-toxic products and prolonged use of the food with respect to extending the safety of the food to bacterial / fungal growth. Have a slow degradation rate to ensure food waste, thereby having the property of minimizing food waste.

  The invention has been described broadly and generically herein. Each of the finer classes and sub-groups within the general disclosure also form part of the present invention. This is a general statement of the invention, with the proviso or negative limitation that removes any subject matter from its class, regardless of whether the deleted material is specifically recited herein. Includes description.

Other embodiments are within the following claims and non-limiting examples. In addition, if any feature or aspect of the invention is described in terms of a Markush group, the invention is hereby also described in terms of any individual element or subgroup element of the Markush group. Will be understood by those skilled in the art.
[Experiment]

  Various embodiments show methods for designing and manufacturing environmentally friendly packaging films for food technology. Specifically, films according to embodiments disclosed herein have sufficient UV absorbing, anti-poisoning and anti-bacterial / anti-fungal functions, but are naturally degradable and suitable for food packaging films. Designed with mechanical and mechanical properties. The films disclosed herein degrade in the natural environment (e.g., seawater) to yield non-toxic products and provide extended periods of use with respect to extending the safety of foods against bacterial / fungal growth. It has a slow degradation rate to ensure, thereby having the property of minimizing food waste.

  The environmentally friendly packaging film disclosed herein may include two components.

  (A) Degradable polymeric substrates as a barrier between food and the external environment. It has appropriate optical and mechanical properties, while at the same time has appropriate UV absorption and antioxidant functions. The polymeric substrate can also serve as a support for the naturally added material.

  (B) Naturally added materials comprising small particles that are uniformly dispersed in a polymer matrix. Produces antibacterial / antifungal properties.

  Environmentally friendly packaging films can be manufactured using a three-step physical method without using any solvents / chemicals. The degradable polymer (eg, poly (ε-caprolactone) (PCL) shown in FIG. 1A) is first melted and heated to a temperature just above its melting point (eg, 65 ° C. for PCL). The substrate may then be formed using a two-roll milling technique. Second, the substrate is compounded with small particles as an additive (eg, chitosan (CS) powder with a particle size of less than 75 μm) using a combination of sieving and two-roll milling techniques (FIG. 1B). Good.

  The small particle additive material uses a combination of lysis and freeze-drying techniques (FIGS. 2A, 2B, 2C) to enhance the antimicrobial / antimycotic properties of natural ingredients (eg, grapefruit seed extract (GFSE)). May be changed. Finally, the composite pellets may then be heat pressed into a film (eg, 65 ° C. and 30 Mpa for the PCL / CS and PCL / CS / GFSE films of FIG. 1C).

  The incorporation of a small amount of added particles into the polymeric substrate (eg, 15 wt% CS powder in the PCL substrate) reduces the overall appearance and flexibility of the environmentally friendly packaging film when compared to pure PCL film (Figure 3A and 3B) and the transparency (FIGS. 3F and 3G) are not changed.

  The incorporation of natural food preservatives (eg, GFSE / CS in a ratio of 1: 1 ml / g (GFSE volume / CS weight)) also affected the overall appearance, flexibility (FIG. 3C), and clarity (FIG. 3C) of the film. 3H). In contrast, CS / GFSE films (eg, GFSE / CS, 1: 1 ml / g) cannot be curved (FIG. 3D) and are completely opaque (FIG. 3I). Commonly used synthetic polyethylene (PE) films also exhibit similar clarity to PCL / CS and PCL / CS / GFSE films (FIG. 3J), but exhibit poor processing capabilities and tend to adhere easily (FIG. 3E).

  The incorporation of a small amount of CS microparticles (15 wt%) or CS / GFSE microparticles (15 wt%, CS: GFSE ratio, 1: 1 g / ml) was lower than that of the water contact angle on pure PCL film by PCL / CS and PCL / Only a small change in the water contact angle on the CS / GFSE film (FIGS. 4A to 4D). Although PE films have higher water contact angles than PCL-based films, it demonstrates that the surface properties to moisture adhesion are similar. (FIG. 4A, FIG. 4B, FIG. 4C, FIG. 4D) With various weight percentages of incorporation of added particles (eg, 0 to 25 wt% CS powder in PCL substrate), the mechanical properties of environmentally friendly packaging films are: May vary and tensile strength and breaking strain (eg, up to 15 wt% CS) approach those of PE films (7-30 Mpa tensile strength and 50-190% breaking strain, Table 1). .

Table 1: Mechanical properties of environmentally friendly packaging films of different compositions (n = 4)

  The environmentally friendly packaging film shows a crack-free topography on its surface (FIGS. 5A and 5B) and shows additive particles that are uniformly dispersed in the polymeric matrix (FIGS. 5C and 5D). Such films exhibit a combination of chemical properties from both the substrate and the additive particles and do not induce any changes to the typical chemical bonds of each component during the manufacturing process (FIG. 6).

  An environmentally friendly packaging film (eg, 15 wt% CS powder) gains improved UV absorption properties when compared to that of a pure PCL film (FIG. 7A), and has a nearly 90% DPPH (DPPH: 1,1). -Diphenyl-2-picrylhydrazyl, standard oxidant), showing robust antioxidant capacity with removal within 72 hours (FIG. 7B).

  Films also exhibit degradability in the natural environment (eg, seawater) and have slow degradation rates that can be altered by incorporation of added particles (eg, 15 wt% CS powder in FIG. 8). Such films (e.g., containing 15 wt% CS powder and 15 wt% CS / GFSE powder) have the potential to interfere with the development of fungal growth so as to increase the shelf life of the food (e.g., In the environmentally friendly packaging film of FIG. 9 compared to PE and PCL films, the shelf life of the bread is increased by a factor of about 2-3), which is due to the incorporation of added particles.

  Although the invention has been shown and described in detail with reference to exemplary embodiments thereof, it is to be understood that the invention has been described in detail without departing from the spirit and scope of the invention as defined by the following claims. Those skilled in the art will appreciate that various changes may be made, and in detail.

Claims (28)

  A packaging material comprising a degradable polymer and a natural antimicrobial agent, wherein the degradable polymer forms a polymer matrix in which the natural antimicrobial agent is dispersed.   The packaging material according to claim 1, wherein the natural antibacterial agent is selected from the group consisting of chitosan, chitin, lignin, derivatives thereof, combinations thereof, and copolymers thereof.   The packaging material according to claim 1, wherein the natural antibacterial agent includes chitosan.   The packaging material according to any one of claims 1 to 3, wherein the natural antibacterial agent further comprises a natural bioactive agent.   The natural bioactive agent is selected from the group consisting of grapefruit seed extract, olive leaf extract, natamycin, hinokitiol, lysozyme, bacteriocin, essential oil, tea tree oil, lemon peel, pomelo, cinnamon, and combinations thereof. The packaging material according to claim 4.   The packaging material according to claim 4 or 5, wherein the natural bioactive agent comprises a grapefruit seed extract.   The packaging material of any one of claims 4 to 6, wherein the ratio of the natural bioactive agent to the natural antimicrobial agent ranges from about 1: 1 to about 3: 1 ml / g.   The packaging material according to any one of claims 1 to 7, wherein the natural antibacterial agent includes particles having a size of 75 µm or less.   9. The packaging material according to any one of the preceding claims, wherein the amount of the natural antimicrobial agent in the polymeric substrate ranges from about 0.01 wt% to about 40 wt%.   10. The packaging material according to any one of the preceding claims, wherein the amount of the natural antimicrobial agent in the polymeric substrate ranges from about 0.01 wt% to about 15 wt%.   The degradable polymer includes poly (ε-caprolactone), aliphatic polyester, polylactide, poly (glycolide), poly (hydroxyester ether), poly (hydroxybutyrate), poly (anhydride), polycarbonate, poly (amino acid) 11) selected from the group consisting of), poly (ethylene oxide), poly (phosphazene), polyetheresters, polyesteramides, polyamides, combinations thereof, and copolymers thereof. Packaging material as described.   The packaging material according to any one of claims 1 to 11, wherein the degradable polymer includes poly (ε-caprolactone).   13. The packaging material according to any one of the preceding claims, wherein the natural antimicrobial agent is at least substantially uniformly dispersed in the polymeric matrix.   The packaging material according to any one of claims 1 to 13, wherein the packaging material is a food packaging film. A method for preparing the packaging material according to any one of claims 1 to 14, wherein the method comprises:
a) providing a natural antimicrobial agent;
b) dispersing the natural antimicrobial agent in a degradable polymer to obtain the packaging material;
A method comprising:   16. The method of claim 15, wherein said natural antimicrobial agent further comprises a natural bioactive agent. Providing the natural antimicrobial agent,
a) dissolving the natural antimicrobial agent and the natural bioactive agent in an aqueous solution to form an aqueous mixed solvent;
b) drying the aqueous mixed solvent to obtain the natural antimicrobial agent;
17. The method of claim 16, comprising:   18. The method of claim 17, wherein dissolving the natural antimicrobial agent and the natural bioactive agent in an aqueous solution is performed at ambient conditions.   The step of dissolving the natural antimicrobial agent and the natural bioactive agent in an aqueous solution is performed at a ratio of the natural bioactive agent to the natural antimicrobial agent in a range from about 1: 1 to about 3: 1 ml / g. Item 19. The method according to Item 17 or 18.   The method according to any one of claims 17 to 19, wherein the step of drying the aqueous mixed solvent is performed by a two-step method of freeze-drying and vacuum drying.   21. The method of claim 20, wherein the freeze drying is performed for a time ranging from about 1 hour to about 3 hours.   22. The method of claim 20 or 21, wherein the step of vacuum drying is performed for a time ranging from about 1 day to about 3 days.   23. The method according to any one of claims 15 to 22, wherein the natural antimicrobial agent comprises particles having a size of 75m or less. Dispersing the natural antimicrobial agent in the degradable polymer,
a) melting the degradable polymer;
b) mixing the natural antimicrobial agent with the melted degradable polymer to form a polymer mixture;
c) heat pressing the polymer mixture;
24. The method according to any one of claims 15 to 23, comprising:   25. The method of claim 24, wherein melting the degradable polymer is performed at a temperature above the melting point of the degradable polymer using a two-roll milling process.   The step of mixing the natural antimicrobial agent with the molten degradable polymer comprises sieving the natural antimicrobial agent onto the molten degradable polymer while the two-roll milling process is performed. 26. The method of claim 25, comprising the step of clinging.   27. The method according to any one of claims 24 to 26, wherein the step of heat pressing the polymer mixture is performed at a pressure ranging from about 20 MPa to about 40 MPa.   28. Use of a packaging material according to any one of claims 1 to 14 or a packaging material prepared by a method according to any one of claims 15 to 27 in food packaging.