WO2020080542A1

WO2020080542A1 - Freshness-retaining film and freshness-retaining container

Info

Publication number: WO2020080542A1
Application number: PCT/JP2019/041207
Authority: WO
Inventors: 佐々木　正人
Original assignee: 佐々木　正人; 株式会社ニッショー化学; 株式会社ニッショー化学ホールディングス; 西山広文
Priority date: 2018-10-19
Filing date: 2019-10-18
Publication date: 2020-04-23
Also published as: CN112969586A; JPWO2020080542A1

Abstract

Provided is a freshness-retaining film capable of efficiently decomposing ethylene generated from foods (in particular, fresh foods, vegetables, fruits, and the like) and plants other than food plants into water and carbon dioxide molecules not only under light conditions but also in darkness. This freshness retaining film is provided with a first layer 1, a second layer 2, and a third layer 3. The second layer 2 is located between the first layer 1 and the third layer 3. The first layer 1 contains zinc oxide in a resin which tends not to transmit oxygen and water vapor, and the zinc oxide has a photocatalytic active site coated with a coating agent. The coverage of the zinc oxide with the coating agent is 0.3 to 1.2%. The second layer 2 contains an organic fungicide in a resin which tends not to transmit oxygen and water vapor. The third layer 3 is made of a resin which tends not to transmit oxygen and water vapor.

Description

Freshness preservation film and freshness preservation container

The present invention relates to a freshness-keeping film and a freshness-keeping container used for keeping food (especially fresh foods, fruits and vegetables, etc.) and freshness of plants other than food (including keeping growth of plants).

ㆍ Plastic film exhibits various physical properties (water vapor permeability, gas permeability) due to differences in material, manufacturing method such as stretching method, and thickness. For example, a film having low water vapor permeability and high gas permeability (for example, polyethylene film) is generally used for packaging of fruits and vegetables. When packaging fruits and vegetables using such a film, the humidity inside the packaging bag or packaging container is close to 100%. As a result, transpiration of fruits and vegetables is suppressed. Therefore, since the plastic film packaging can completely suppress the wrinkling of fruits and vegetables due to the transpiration action, the fresh consumption of fruits and vegetables in circulation can be suppressed. However, when the temperature is high, it may cause gas damage in the fruits and vegetables themselves, reproduction of microorganisms, and generation of aging hormone and ethylene gas, which may cause aging ripening and spoilage. Has been done. For example, in each distribution process of fruits and vegetables from the production area to the consumption area, even a trace amount of 0.005 ppm of ethylene gas may cause irreversible damage to 25 to 46% of the entire distribution amount. Thus, there is no safe level for ethylene gas concentration. Generally, in the storage room of a distribution center, ripe agricultural products and non-ripened agricultural products are in a mixed state, and it is calculated that the loss after harvest due to ethylene gas reaches 25 to 30%. Many companies have realized such a technology for decomposing ethylene gas using a photocatalyst (see Patent Documents 1 to 3, for example).

Further, Patent Document 4 discloses an anti-aging transportation container using coated photocatalyst particles which are partially coated with a photo-inert inorganic substance for long-term maintenance of freshness. In this Patent Document 4, as described as "things coated like konpeito (Konpeito type particles)" and "one coated like muskmelon mask (muskmelon type particles)", The partial coating covers the surface of the photocatalyst particles so as to cover a certain area.

JP, 9-196545, A JP, 2009-35327, A JP, 2010-207223, A Utility model registration No. 3115187

However, when a photocatalyst is used, it requires light conditions, and more hydroxyl radicals are generated by the photocatalytic action to decompose ethylene and simultaneously cause damage to plants such as vegetables and fruits. It has the drawback of decomposing, degrading or discoloring the resin forming the film or container. In addition, it is known that acetaldehyde is produced in food freshness-keeping agents that also use oxygen scavengers, and these odors are not only perceived as a pungent odor or a strange odor when the bag is opened, but also when eating food. However, since the odor transferred to food gives a consumer discomfort and a feeling of strangeness, it is necessary to remove the odor.

Therefore, the present invention has been made in view of the above situations, and not only under light conditions but also in the dark, food (especially fresh foods, fruits and vegetables) and ethylene generated from plants other than food (EN) Provided is a freshness-retaining film which can be efficiently decomposed into water and carbon dioxide molecules. Moreover, it aims at providing the freshness preservation container using the above-mentioned freshness preservation film.

(1) The freshness preservation film of the present invention comprises a first layer, a second layer and a third layer, the second layer being in the middle of the first layer and the third layer. The first layer contains a zinc oxide whose photocatalytically active site is coated with a coating agent in a resin having a property of hardly permeating oxygen and water vapor, and the coating rate of the zinc oxide by the coating agent is 0. The second layer is a layer containing an organic antifungal agent in a resin having a property of hardly permeating oxygen and water vapor, and the third layer is It is characterized in that it is a layer made of a resin having a property of making it difficult for oxygen and water vapor to permeate.

(2) The freshness-keeping film of the present invention is characterized in that the third resin layer does not contain the zinc oxide and the organic fungicide.

(3) The freshness keeping film of the present invention is characterized in that the coating amount of the coating agent is 0.2 to 10% by weight based on the weight of the zinc oxide.

(4) The freshness keeping film of the present invention is characterized in that the resin in at least one of the first layer, the second layer and the third layer is polyethylene.

(5) The freshness keeping film of the present invention is characterized in that the organic antifungal agent is 2-methoxycarbonylamino-benzimidazole.

(6) The freshness-keeping container of the present invention comprises the freshness-keeping film according to any one of the above (1) to (5), which is any one of a bag-like structure, a tubular structure, a tunnel structure, a layered structure, and a nested structure. It is characterized by being formed into a structure including one or more.

According to the above configuration, plastic packaging storage is performed that can be stored for a long period of time while maintaining the freshness of food (particularly fresh foods, fruits and vegetables) and plants other than food (fresh flowers, etc.) not only under light conditions but also in the dark. It becomes possible. Here, plastic packaging and storage utilizes the difference in permeability between water vapor and gas in the plastic film to package food (especially fresh food, fruits and vegetables) and non-food plants (fresh flowers, etc.) with the plastic film. This means that transpiration and respiration during storage can be suppressed and freshness can be maintained for a long period of time. In the gas environment in the sealed film, oxygen in the film is consumed by the respiratory action of food (particularly fresh foods, fruits and vegetables) and plants other than food (fresh flowers, etc.) itself, and carbon dioxide gas is accumulated. The gas environment in the film changes depending on the ambient temperature, the material of the packaging material, the food to be packaged (especially fresh foods, fruits and vegetables, etc.) and the plants other than food (fresh flowers, etc.), for example, the thickness of leaf vegetables at low temperatures (5 ° C or less). When sealed with 0.03 mm low density polyethylene, the gas environment inside the film is stable with an oxygen concentration of 2-3% and carbon dioxide gas of 5-10%. Since the oxygen concentration in the atmosphere is 20.9% and carbon dioxide is less than 0.1%, it becomes an environment of low oxygen-high carbon dioxide concentration compared to the atmosphere, and when stored in this environment, it is compared to that stored in the atmosphere. Therefore, the effect of suppressing the deterioration of freshness (CA effect) can be obtained.

The above-mentioned plastic film or plastic container packaging storage is also called MA storage (Modified Atmosphere), and is used as an interior material when distributing many foods (particularly fresh foods, fruits and vegetables) and plants other than food (fresh flowers, etc.). It's being used. In addition to the above-mentioned CA effect, 1. Suppression of wilting by transpiration of plants such as fruits and vegetables or food itself 2. Suppression of surface mechanical damage, 3. This is to obtain the effect of suppressing dew condensation on the surface of fruits and vegetables due to temperature fluctuations.

Further, the zinc oxide whose photocatalytic active site is coated with a coating agent, by coating the active site of the zinc oxide photocatalyst with a coating agent, suppresses the activity of the photocatalyst and suppresses the generation of active oxygen, Elutes zinc ions from zinc oxide to exert antibacterial, antifungal and deodorant effects. In addition, the second resin layer containing an organic antifungal agent further improves the effects of antibacterial, antifungal, deodorant, etc., and maintains good freshness even for meat, fish, flowers, etc. is doing.

It is sectional drawing of the freshness preservation film in embodiment of this invention. It is a figure which shows the change of the AGEs value of pork. It is a figure which shows the comparison result of the freshness preservation effect of the freshness preservation film and the comparative examples 1 and 2 in the Example which concerns on this invention. It is a figure which shows the comparison result of the freshness preservation effect of the freshness preservation film in the Example which concerns on this invention, and Comparative Examples 1 and 2, and is a figure different from FIG. It is a figure which shows the comparison result of the freshness preservation effect after 24 hours progress. It is a figure which shows the freshness preservation effect with respect to the vacuum-processed meat of each freshness preservation film. It is a figure which shows the difference of the freshness preservation effect of the freshness preservation film in the Example which concerns on this invention, and Comparative Examples 1 and 2. It is a figure which shows the comparison result of the freshness preservation effect of "Tuna 7 days old" with the freshness preservation film in the Example which concerns on this invention, and Comparative Examples 3 and 4. It is a figure which shows the comparison result of the freshness retention effect of "fresh tuna 10 days fresh" with the freshness retention film in the Example which concerns on this invention, and Comparative Examples 3 and 4. It is a figure which shows the storage state of the oxygen water mist process in the Example which concerns on this invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG.
FIG. 1 is a cross-sectional view of a freshness keeping film according to an embodiment of the present invention.
As shown in FIG. 1, the freshness keeping film of the present invention includes a first layer 1, a second layer 2 and a third layer 3 from the top.
The first layer 1 is a layer containing zinc oxide whose photocatalytically active site is coated with a coating agent in a resin having a property of making it difficult for oxygen and water vapor to permeate.
The second layer 2 is an intermediate layer between the first layer 1 and the third layer 3, and is a layer containing an organic antifungal agent in a resin having a property of making it difficult for oxygen and water vapor to permeate.
The third layer 3 is a layer made of a resin having a property of making it difficult for oxygen and water vapor to permeate.

First, the first layer 1 will be described in detail.
The first layer 1 is a resin layer containing zinc oxide whose photocatalytically active site is coated with a coating agent. The resin used for the first layer 1 is not particularly limited as long as it is a material that does not easily transmit oxygen and water vapor. Specifically, LDPE: low density polyethylene, HDPE: high density polyethylene, OPP: stretched polypropylene, CPP: unstretched polypropylene, ON: stretched nylon (polyamide), CN: unstretched nylon (polyamide), BDR: polybutadiene, PMP. : Polymethyl bentene, BOV: Stretched vinylon, OV: Stretched vinylon coated with PVDC, PET: Polyethylene terephthalate, PVDC: Polyvinyldene chloride, KOP: Polyvinyldene chloride coated OPP, KON: Polyvinylidene chloride coated ON, EVOH: Ethylene / vinyl alcohol Copolymer, EVA: ethylene / vinyl acetate copolymer, PS: polystyrene, PT: normal cellophane, MST: polymer type moisture-proof cellophane, ABS: acrylonitrile-butadiene-styrene copolymer, etc. And the like. These can be used alone or in combination. Here, the term “hardly permeates oxygen and oxygen” means that oxygen and water vapor do not permeate through the resin film in normal use. If the oxygen permeability is high, there is a problem that the object to be packaged is oxidized. In addition, when the water vapor permeability is high, the humidity inside the film when the film is formed into a bag is excessively lowered, and the plant is withered.

Specific examples of the coating agent include KBM-403 (γ-glycidoxypropyltrimethoxysilane) and KBM-503 (γ-methacryloxypropyltrisilane), which are silane coupling agents manufactured by Shin-Etsu Chemical Co., Ltd. Methoxysilane), but mainly involved in the reaction with the surface of the inorganic oxide particles such as zinc oxide is a silanol group produced by hydrolysis of the hydrolyzable group of the silane coupling agent, It is well known that organic functional groups such as epoxy groups and methacrylic groups can mainly react with various resins and bond with them. For the purpose of suppressing the photocatalytic activity, other silane coupling agents, that is, silane coupling agents having a vinyl group, a mercapto group, an amino group or the like may be used.

Incidentally, it is not clear why the coating treatment with the silane coupling agent can suppress the photocatalytic activity of zinc oxide in a smaller amount than the coating treatment with the inorganic substance, but the active site controlling the photocatalytic activity of the zinc oxide particle surface and the silane coupling agent The reactivity with the ring agent is higher than the reactivity with the inorganic surface treatment agent and the active site that controls the photocatalytic activity of the surface of the zinc oxide particles, and therefore the silane coupling agent has a small coating amount. Therefore, it is presumed that the active sites that control the photocatalytic activity on the surface of the zinc oxide particles are killed without waste.

Zinc oxide whose photocatalytically active site is coated with a silane coupling agent which is a coating agent (hereinafter, also referred to as “silane coupling zinc oxide”) may be obtained by a so-called wet synthesis method, or a so-called dry method. It may be obtained by a synthetic method. The coating treatment method of the zinc oxide powder with the silane coupling agent may be a so-called wet method in which the silane coupling agent is added while stirring the slurry of the zinc oxide powder, and a Henschel mixer or a high speed mixer capable of high speed rotation. A so-called dry method in which the silane coupling agent is sprayed or dropped while stirring the zinc oxide powder at high speed with a so-called dry method, or the silane coupling agent carried with an inert gas such as nitrogen is introduced into the reaction vessel containing the zinc oxide powder. However, a so-called vapor phase method of performing coating treatment may be used.

In the freshness keeping film of the present invention, the coating rate of zinc oxide with a coating agent such as the above-mentioned silane coupling agent is essential to be 0.3 to 1.2%, and 0.5 to 0. It is more preferably 6%. If the coverage of zinc oxide is less than 0.3%, the photocatalytic activity of zinc oxide cannot be sufficiently suppressed. On the other hand, if the coverage of zinc oxide exceeds 1.2%, the elution of zinc ions is hindered, and the effects of sterilization, antibacterial, stick mold, deodorization, etc. cannot be obtained.

Regarding the amount of the silane coupling agent used, it is necessary to consider the specific surface area of the zinc oxide powder to be coated. For example, the zinc oxide powder used had a specific surface area by the BET method of 20 m ² / g, and the photocatalytic activity of zinc oxide could be suppressed almost completely by coating this with a 1 wt% silane coupling agent. When coating a finer zinc oxide powder with a larger specific surface area for the same purpose, the photocatalytic activity cannot be sufficiently suppressed unless the coating amount is increased based on the coverage. Inferred. In other words, it requires coverage of about 20% in the case of performing the coating treatment of the zinc oxide powder having a remarkably large specific surface area (e.g. 400 meters 2 / ^g), conversely, the specific surface area is about several m ^{2 /} g When coating zinc oxide powder having a relatively large particle size, a sufficient effect can be expected even with a coating amount of about 0.1%. Therefore, the usual range of the coating amount is 0.1 to 20% by weight, preferably 0.2 to 15% by weight in consideration of dispersibility, and preferably 0.1 to 10% by weight in consideration of cost. It is preferably 0.2 to 10% by weight.

In the silane-coupled zinc oxide contained in the freshness-keeping film of the present invention, the photocatalytic activity can be suppressed with a smaller coating amount, that is, the relative content of zinc oxide can be suppressed as much as possible. It retains its ultraviolet absorbing effect as it is, and despite its photocatalytic activity being suppressed, it retains its bactericidal, antibacterial, antifungal and deodorizing effects. The reason for this is due to the zinc ions contained in the silane coupling zinc oxide. That is, it is due to the action of trace metals. When the zinc oxide contained in the freshness keeping film of the present invention is completely coated with a coupling agent, zinc ions cannot be eluted. Therefore, in the freshness keeping film of the present invention, it is essential that the zinc oxide coating is only on the photocatalytically active portion.

To further improve the dispersibility in the resin, it is necessary to select the silane coupling agent in consideration of the compatibility between the resin used and the organic functional group of the silane coupling agent. This is a point of improving the dispersibility which cannot be achieved by the surface coating treatment with an inorganic substance such as Al, Si, Zr or Sn oxide or hydroxide based on the conventional technique. For example, it is used in a low density polyethylene resin. In this case, it is preferable to coat the zinc oxide powder with a silane coupling agent KBM-503 (γ-methacryloxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.

The silane-coupled zinc oxide contained in the freshness-keeping film of the present invention has ultraviolet absorption, sterilization, antibacterial, antifungal, and deodorizing effects, but is used as an additive whose photocatalytic activity is suppressed. By being used by adding it to a product or an oil and fat composition, effects such as ultraviolet absorption, sterilization, antibacterial, antifungal, deodorization, etc. are achieved, and since the photocatalytic activity is suppressed, the resin composition and the oil and fat composition decompose. No deterioration, deterioration or discoloration. When used as an additive in the present invention, the silane coupling zinc oxide powder may be used alone or as a mixture with other components.

Kneading the above silane-coupling zinc oxide into a resin composition, for example, forming a film, when using it as a packaging material for foods, etc., prevent discoloration of foods due to ultraviolet rays, and at the same time sterilize, antibacterial Also, it is possible to prevent spoilage due to antifungal action and prevent unpleasant odor during opening due to deodorizing action.

In the present invention, the above-mentioned silane-coupled zinc oxide preferably has a particle size of about 40 nm to 400 nm, more preferably 100 nm to 200 nm. Silane-coupled zinc oxide is added to the film material made of the above resin at least on the order of ppm or ppb (1 ppb to 12 ppc (0.0000001% to 12%), preferably 1 ppb to 5 ppc (0.0000001% to 5). %) (Approx.)) And mixed (containing) or applied to the surface of the film material. When the particle size is less than 40 nm or the content is less than 1 ppb, the frequency of contact with ethylene gas is reduced and the ethylene decomposing ability is reduced. On the other hand, if the particle size exceeds 400 nm or the content exceeds 12 ppc, the transparency of the freshness-keeping film deteriorates. Here, when applying to the surface of the film material, it is carried out by spray-applying a spreading agent to which the above-mentioned silane coupling zinc oxide is added at a mass ratio of 10 ppb to 10 ppc and naturally drying. Examples of the base material of the spreading agent include polyalkylene glycol alkyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene octyl phenyl ether, soluble starch, casein solution, soy milk, soybean powder and the like.

Next, the second layer 2 will be described.
The second layer 2 is a layer containing an organic antifungal agent in a resin that does not easily transmit oxygen and water vapor. In general, it is difficult to employ an organic fungicide that is excessively toxic in a film for food packaging. However, in the above freshness keeping film, the second layer 2 which is a layer sandwiched between the first layer 1 and the third layer 3 contains an organic antifungal agent. For this reason, when the above freshness-keeping film is used, since the freshness-keeping film does not come into direct contact with the user or the object to be packaged, various organic fungicides can be used without considering the toxicity. . As such an organic fungicide, one that can be added to a freshness-maintaining product and has safety and efficacy is preferable. 2-Methoxycarbonylamino-benzimidazole is particularly preferable.

The resin used for the second layer 2 is not particularly limited as long as it is a material that does not cause problems such as adhesion with an adjacent layer and is difficult to permeate oxygen and water vapor. The resin used for 1 layer 1 can be used. The resin of the second layer 2 may be the same material as the first layer 1 or may be different.

Next, the third layer 3 will be described.
The third layer 3 in the present invention is for keeping the organic antifungal agent of the second layer 2, which is not a food additive, inside so as not to come into direct contact with the user of the freshness-keeping film or the article to be packaged. Is. The resin used for the third layer 3 is not particularly limited as long as it is a material that does not cause a problem in adhesion with an adjacent layer, and is a material that does not easily allow oxygen and water vapor to permeate. The resin used for 1 layer 1 can be used. The resin of the third layer 3 may be the same material as the first layer 1 or the second layer 2 or may be different.

Next, a method of manufacturing the freshness keeping film will be described.
The method for producing the freshness keeping film of the present invention is not particularly limited as long as it is a method of laminating the above-mentioned first layer 1, second layer 2 and third layer 3 in a predetermined order. Typical methods for producing the freshness-keeping film include a laminating method and a coextrusion method. Specifically, each layer is created by a processing method such as a T-die method or an inflation molding method, and these layers are laminated in a predetermined order by a laminating method so that the layers are laminated to maintain freshness of the multilayer structure. A film is obtained. As a laminating method, a method using an adhesive or a pressure-sensitive adhesive, a thermocompression bonding method, or the like can be adopted. Further, the first layer 1, the second layer 2, and the third layer 3 are simultaneously extruded by the coextrusion method to obtain a freshness-keeping film having a multilayer structure. The method of performing co-extrusion is not particularly limited and may be a known method such as a T-die method or an inflation method.

The thickness of the freshness-keeping film is not particularly limited as long as it does not impair the object of the present invention. The thickness of the freshness-keeping film is preferably such that flexibility and processability that are easy to use and durability that does not easily stretch or break are compatible. Further, in terms of raw material cost, it is preferable that the film is thinner because the manufacturing cost of the freshness-keeping film can be kept low.

The freshness preservation film may include various functional layers in addition to the first layer 1, the second layer 2 and the third layer 3 described above. The above-mentioned first layer 1 and third layer 3 except the above-mentioned second layer 2 may or may not be the outermost layers, respectively.
The outermost layer of the freshness-keeping film, for example, in order to enhance the design of the freshness-keeping film, is provided with a decorative layer having a pattern or pattern on the surface by a printing method or embossing, or a freshness-keeping film. A hard code layer may be provided in order to impart physical durability or chemical durability to the surface.

Further, various functional layers may be provided between the first layer 1 and the second layer 2 and between the second layer 2 and the third layer 3. A typical example of such a function is an adhesive layer (adhesive layer).

Further, the freshness-keeping film of the present invention can be processed into a bag-like structure, a tubular structure, a tunnel-like structure, a layered structure, or a nesting-type freshness-keeping container by further processing the above-mentioned laminated film. Further, the container may be a box-shaped freshness-keeping container having a lid provided with a freshness-keeping film inside by injection molding or the like. As a manufacturing method of such an aspect, any molding method may be used as long as it is a method capable of solid-forming into a fixed shape such as a box shape. Further, a freshness keeping container according to another embodiment of the present embodiment, the silane coupling zinc oxide coated with a silane coupling agent on the photocatalytically active site is mixed in the same proportion as in the case of the freshness keeping film (containing). Alternatively, the solid may be formed into a box shape and then applied on the surface. Note that examples of the box shape here include a cube, a rectangular parallelepiped, a triangular prism, a cylinder, and a triangular pyramid, but any shape can be used as long as it can store things inside. May be The container material used for the freshness-keeping container according to this alternative form is not particularly limited as long as it is a material that does not easily allow oxygen and water vapor to permeate, but specifically, low density polyethylene (LDPE) ( High pressure method), linear low density polyethylene (LLDPE), high density polyethylene (HDPE) (low pressure method), ultra high molecular weight polyethylene (UHMW-PE), crosslinked polyethylene, polyethylene terephthalate (PET), acrylonitrile styrene (AS) , Polypropylene (PP), polystyrene (PS), polycyclohexanedimethylene terephthalate = high heat resistant engineering plastic (PCT), saturated polyester resin, polymethylpentene (TPX), acrylonitrile-butadiene-styrene copolymer (ABS), etc. , These alone or in pairs Together it can be used.

Further, as the resin film in the freshness keeping film of the present invention, a resin film having an ethylene adsorption capacity may be used. Thus, when ethylene is generated from food (particularly fresh foods, fruits and vegetables) and plants other than food, the freshness-keeping film itself according to the present invention can function as an adsorbent for ethylene. Is more likely to adsorb ethylene. In addition, the effect of suppressing the respiration and the transpiration induced by the water and carbon dioxide generated by the ethylene decomposition can be improved more than before, and by extension, food (particularly fresh foods, fruits and vegetables) and plants other than food can be used. It can contribute to the preservation of freshness.

Further, the method of applying the freshness-keeping film of the present invention, for example, by processing the freshness-keeping film into a bag shape or a container, as a freshness-keeping bag or a freshness-keeping container, a plant or food such as fruits and vegetables is enclosed inside, Alternatively, a plant or food such as fruits and vegetables is covered with the freshness-keeping film, and the plant or food such as fruits and vegetables is directly inoculated, or a freshness-keeping film is directly attached to the inner surface of a cardboard or container for storing the plant or food such as fruits and vegetables. It can be attached or used by being attached to the inner surface of a facility such as a storage for storing plants such as fruits and vegetables or food. Further, for example, a freshness-keeping film may be attached to a ventilation device or an air intake device in a storage room for plants such as fruits and vegetables or foods. Furthermore, by sticking or laminating the freshness-keeping film of the present invention on the inner wall or the drawn-out portion of the refrigerator, or by applying the freshness-keeping container of the present invention to the refrigerator compartment, the freshness-keeping function inside the refrigerator It is also possible to add.

The fruits and vegetables to be stored using the freshness-keeping bag and the freshness-keeping container according to the present embodiment should be appropriately determined based on the type of plant, growing method, climate and the like.

Note that the above-mentioned silane-coupled zinc oxide is capable of decomposing not only ethylene generated from plants such as fruits and vegetables or foods but also saprophytic gases such as aldehydes that cause corrosion. After storage, the saponification gas is decomposed at the same time as ethylene is decomposed to improve the freshness-retaining effect. As a condition for maintaining the freshness, ethylene decomposition functions even in a dark place, similarly to under the light condition. Further, under the humidity maintaining condition which is an important factor in the preservation of plants such as fruits and vegetables or food, even if the gas component is changed, the ethylene decomposing performance is exhibited similarly to the low humidity condition. Specifically, it is preferable to apply humidification in individual packaging or adjust the gas partial pressure to maintain freshness, and especially to arrange it near the surface of plants or food (for example, the surface of fruit parts of fruits and vegetables). It is more preferable to apply a freshness keeping sheet.

Here, since the freshness-keeping bag has a hollow structure with a high porosity and a high specific surface area, the minimum replenishment of oxygen carried by the respiration of plants, and the carbon dioxide that suppresses respiration is decomposed by ethylene. Can be provided. This makes it easier to maintain freshness through the suppression of respiration of plants such as fruits and vegetables or food, and promotes shelf life. The freshness-keeping bag and the freshness-keeping container have high water-absorbing power (power to adsorb water) on the surface, and can impart water-retaining property and moisture-retaining property to plants such as fruits and vegetables or food.

Therefore, when storing plants or foods such as fruits and vegetables, by applying a freshness-keeping bag or a freshness-keeping container, for the decomposition of ethylene effectively and the decomposition of ethylene in the freshness-keeping film into carbon dioxide and water, As a result, it is possible to suppress the respiration of plants or foods such as fruits and vegetables and to promote the retention of freshness by applying humidity to the plants or foods such as fruits and vegetables.

Hereinafter, the freshness maintaining layer film of the present invention will be described in more detail with reference to examples. The freshness keeping film of the present invention is not limited to these examples.
The freshness-keeping film of the present invention (Example 1), the freshness-keeping film having only the first layer (Comparative Example 1), the blank film having only the third layer (Comparative Example 2), and a commercially available plastic bag for storage (Comparative Example 3) The freshness-retaining effect of the freshness-retaining film of the present invention was verified by measuring the AGEs content of pork or tuna using a freshness-preserving antibacterial pack (Comparative Example 4). In addition, AGEs are advanced glycation end products, that is, "substances formed by heating proteins and sugars", which are toxic and cause aging.

1. Method for manufacturing freshness-keeping film <Example 1>
First, low-density polyethylene was coated with zinc oxide (trade name: AP-MO, manufactured by Nissho Chemical Co., Ltd.) whose photocatalytic active site was coated with a silane coupling agent as a coating material in a mass ratio of 0.5% of the whole. And mixed so as to obtain a film-shaped first layer by inflation molding. The silane-coupling zinc oxide was zinc oxide particles in which the photocatalytically active sites were coated with a silane coupling agent at a mass ratio of 0.5%.
Next, 2-methoxycarbonylamino-benzimidazole (trade name: AP-OK, manufactured by Nissho Chemical Co., Ltd.) was mixed with low-density polyethylene, and this was subjected to inflation molding to form a film-shaped second layer. . Next, low-density polyethylene was subjected to inflation molding to form a film-shaped third layer.
The first layer, the second layer, and the third layer produced as described above are laminated in this order, and laminated by thermal evaporation (heat sealing) by laminating and molding to obtain the freshness of Example 1 of the present invention having a multilayer structure. A holding film was produced.

<Comparative Example 1>
Only the first layer produced by the production method of Example 1 was used as the freshness keeping film of Comparative Example 1.

<Comparative example 2>
Only the third layer produced by the production method of Example 1 was used as the freshness keeping film of Comparative Example 2.

<Comparative example 3>
Ziploc® was used as Comparative Example 3.

<Comparative example 4>
Keypod (registered trademark) was used as Comparative Example 4.

2. Evaluation of freshness retention effect As test materials, pork immediately after slaughter (35 minutes after slaughter, measurement after 2 hours) provided by Daisho Kanayama Ranch Co., Ltd., 14 days after slaughter, refrigerated for 4 days Pork 1, slaughtered 13 days, refrigerated preserved pork 2 stored for 5 days, slaughtered 6 days or 7 days later, chilled and vacuumed before shipment Various vacuum-treated vacuum treated pork meat parts (red meat, pork containing sardines) Red meat (fat), fat, skin, etc.) was used. These AGEs fluorescence intensity values were measured using an AGEs measuring instrument (prototype) manufactured by Sharp Corporation. Then, each pork was wrapped with the freshness-keeping film of Example 1 and Comparative Examples 1 and 2, and after being refrigerated and stored for 2 days with a cooling agent, the AGEs fluorescence intensity value was measured again to verify the difference in storage state.

It was found that the AGEs value of pork changes as shown in Fig. 2. Specifically, pork immediately after being slaughtered has the highest AGEs value in all parts, including lean meat, lean meat with lean meat, fat meat, and skin, and thereafter, the value decreases while being refrigerated. Became clear. Also, the AGEs value tended to rise again, albeit slightly, due to the vacuum treatment before shipment. It was suggested that the recovery of the AGEs value improved the preservation condition of meat by vacuum treatment. In particular, the tendency of recovery of the AGEs value was high in a portion containing a large amount of lipid such as red meat and fat containing sardine. In addition, the refrigerated red meat shows the average of AGEs values on the 4th and 5th refrigeration.

As shown in FIG. 3, the freshness-retaining effect of each freshness-keeping film on pork (red meat) was in the order of Example 1, Comparative Example 1, and then Comparative Example 2. In particular, in the freshness-keeping film of Example 1 of the present invention, as shown in FIG. 2, it was found that there is almost no change in the decrease in the fluorescence intensity value of the red meat and AGEs immediately after slaughter. That is, it was revealed that the freshness-keeping film of the present invention has a high freshness-keeping effect on pork.

Fig. 4 shows a spectrum analysis diagram of AGEs fluorescence intensity. The pork lean meat immediately after slaughter showed a high AGEs value (n = 12) as indicated by the fine dotted line. After that, the AGEs value was extremely lowered by the refrigeration treatment for 4 to 5 days. On the other hand, in Comparative Example 1 (solid line) and Comparative Example 2 (dashed-dotted line), almost the same degree of decrease tended to be due to the fact that only two days had passed since the slaughter. On the other hand, it was revealed that the freshness-keeping film of Example 1 (coarse dotted line) of the present invention maintained a high AGEs value even when compared with that immediately after slaughter.

Further, as shown in FIG. 5, when the changes in the AGEs value after the lapse of 24 hours were compared, a large freshness-retaining effect was confirmed with the freshness-retaining film of the present invention.

Next, as shown in FIG. 6, the freshness-preserving effect of each freshness-preserving film on the vacuum-treated meat showed the same tendency as freshness of pork immediately after being slaughtered. However, when pork immediately after slaughter was used, the effect was not apparent in Comparative Example 1, while a clear difference was observed in the pork after vacuum treatment. Further, it was revealed that the freshness-keeping film of the present invention had a higher effect of keeping pork freshness than Comparative Example 1.

Further, as shown in FIG. 7, it was revealed that when the vacuum-treated pork was used, the use of the freshness-preserving film of the present invention exhibited a higher AGEs value than the pork immediately after the vacuum treatment. This result suggests that a higher degree of freshness preservation can be achieved by combining pork with a freshness preservation film by processing. It should be noted that, as shown in FIG. 7, by nature, the AGEs value of pork decreases toward the death of the meat tissue due to the death of the individual. It was suggested that some vital activities were restored by adjusting appropriate oxygen and carbon dioxide partial pressure. Further, it can be seen that there is a difference in the freshness keeping effect between the freshness keeping films of Example 1 and Comparative Example 1 due to the difference in the wavelength peak.

Next, as test materials, tuna (tuna 7 days old) fenced 3 days ago and tuna (tuna 10 days fresh) fenced immediately before the test were used, and AGEs in tuna were used as a standard for each freshness-keeping film. The freshness preservation effect was verified. Note that the tuna fence was cut and then subjected to oxygen water mist treatment, that is, oxidation treatment. Here, the above-mentioned oxygen water mist treatment will be described. When the oxygen water mist treatment is performed, the AGEs value of the early crops increases, and the AGEs value of the latter crops decreases. In the case of tuna, it becomes a late reaction and aging is promoted. As a result, the change in the AGEs value becomes remarkable.

As a test method, as shown in FIG. 8, tuna 7-day old was sealed from the left with Ziploc (registered trademark) of Comparative Example 3, treated with oxygen water mist, and then sealed with Ziploc (registered trademark) of Comparative Example 3. After treatment with oxygen water mist, sealing with the Keypod (registered trademark) of Comparative Example 4 was performed, and after treatment with oxygen water mist, sealing with the freshness keeping film of Example 1 of the present invention was compared. Further, in the above-mentioned test, comparison was made immediately after the above treatment (0 hr), after 12 hours (12 hr), and after 96 hours (96 hr).

From the results of FIG. 8, with respect to the freshness retention effect of “Tuna 7 days old”, in Example 1 in which the freshness retention film of the present invention and the freshness retention film of the present invention were sealed, compared to Comparative Examples 3 and 4, immediately after the above-mentioned treatment. (0 hr), after 12 hours (12 hr) and after 96 hours (96 hr), it was found that the AGEs value decreased little and the effect of keeping freshness was high.

In addition, from the results of FIG. 9, the freshness-retaining effect of “fresh tuna for 10 days” was compared with Comparative Examples 3 and 4 in Example 1 in which the freshness-retaining film of the present invention was sealed with oxygen water mist treatment. It was found that there was little decrease in the AGEs value immediately after the treatment (0 hr), after 12 hours (12 hr), and after 96 hours (96 hr), and the effect of keeping freshness was high.

Therefore, from the results shown in FIGS. 8 and 9, it was confirmed that the sealing treatment with the freshness-preserving film of the present invention exhibited higher freshness retention.

Further, as shown in FIG. 10, when sealed with the freshness-keeping film of the present invention, in Example 1, it was confirmed that the tuna fence was the most reddish and visually fresh. .

When the freshness-keeping film of the present invention is used, in addition to the freshness-keeping film, it is also used as packaging containers, air caps, packing materials, paints, sheet-like wraps (PVC), etc. using regular layer films such as bags, trays and tappers. There is.

3. Coverage of Zinc Oxide Next, the coverage of zinc oxide in the freshness keeping film of the present invention was verified.
<Example 2>
A freshness-keeping film of Example 2 was produced in the same manner as in Example 1 except that the coverage of zinc oxide with the silane coupling agent was 0.3%.

<Example 3>
A freshness-keeping film of Example 3 was produced in the same manner as in Example 1 except that the coverage of zinc oxide with the silane coupling agent was 1.2%.

<Comparative Example 5>
A freshness-keeping film of Comparative Example 5 was produced in the same manner as in Example 1 except that the coverage of zinc oxide with the silane coupling agent was 0.2%.

<Comparative example 6>
A freshness-keeping film of Comparative Example 6 was produced in the same manner as in Example 1 except that the coverage of zinc oxide with the silane coupling agent was 1.3%.

In the freshness-keeping films of Examples 2 and 3 and Comparative Examples 5 and 6, the AGEs fluorescence intensity values were measured in the same manner as above. As a result, in Examples 2 and 3, the AGEs fluorescence intensity was slightly inferior, but good AGEs fluorescence intensity was obtained. The value was obtained. On the other hand, in Comparative Example 5, the coverage of zinc oxide was too small at 0.2%, while in Comparative Example 6, the coverage of zinc oxide was too large at 1.3%. Was not obtained.

Although the embodiments of the present invention have been described above, it should be considered that the specific configurations are not limited to these embodiments. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and further includes meanings equivalent to the scope of the claims and all modifications within the scope. For example, it is effective not only for fruits and vegetables such as tomatoes, but also for root vegetables cultivation, orchid flower cultivation, leaf cultivation at a plant factory, and freshness maintenance of mushrooms.

Claims

A first layer, a second layer, and a third layer,
The second layer is intermediate between the first layer and the third layer,
The first layer contains zinc oxide whose photocatalytically active site is coated with a coating agent in a resin having a property of hardly permeating oxygen and water vapor, and the coating rate of the zinc oxide by the coating agent is 0. 3 to 1.2% of the layer,
The second layer is a layer containing an organic antifungal agent in a resin having a property of making oxygen and water vapor hardly permeate,
The freshness-keeping film, wherein the third layer is a layer made of a resin having a property of making it difficult for oxygen and water vapor to permeate.
The freshness-keeping film according to claim 1, wherein the third layer does not contain the zinc oxide and the organic antifungal agent.
The freshness-keeping film according to claim 1 or 2, wherein the coating amount of the coating agent is 0.2 to 10% by weight based on the weight of the zinc oxide.
The freshness preservation film according to any one of claims 1 to 3, wherein the resin in at least one of the first layer, the second layer, and the third layer is polyethylene.
The freshness keeping film according to any one of claims 1 to 4, wherein the organic antifungal agent is 2-methoxycarbonylamino-benzimidazole.
A freshness-retaining film according to any one of claims 1 to 5 is formed into a structure including any one or more of a bag-shaped structure, a tubular structure, a tunnel structure, a layered structure, and a nested structure. A container for keeping freshness, which is characterized in that