JP7702827B2 - Method for preserving freshness of fruits and vegetables, packaging body and freshness-preserving metal member - Google Patents

Description

This disclosure relates to a method for preserving the freshness of fruits and vegetables, a packaging body, and a metal component for preserving freshness.

Fruits and vegetables are sometimes not consumed immediately after harvest, but are stored during distribution. When storing fruits and vegetables, various studies are being conducted on ways to prevent loss of freshness during storage.

For example, Patent Document 1 describes a freshness-preserving sheet for fruits, vegetables, and flowers, which comprises an undercoat layer made of at least one type selected from an SBR-based emulsion, a vinyl acetate-based emulsion, and an acrylic-based emulsion on one side of paper ^or paperboard, and a polyvinyl dichloride (PVDC) layer of 2 to 5 g/ ^m2 provided thereon, and which is characterized by having a moisture permeability of 20 to 200 g/ ^m2 ·day, an oxygen permeability of 1000 to 50,000 cc/m2·day, and a carbon dioxide permeability of 20,000 cc/ ^m2 ·day or less.

Patent document 2 describes a package in which fruits and vegetables, including lettuce, are stored in a packaging container that includes a polymer film, and the package has an internal carbon dioxide concentration of 1 to 98% by volume and an internal oxygen concentration of 1 to 19% by volume.

JP 2000-025843 A JP 2018-167896 A

As mentioned above, fruits and vegetables may not be consumed immediately after harvest but may be stored during distribution.
Controlled Atmosphere (CA) storage and modified Atmosphere (MA) storage of fruits and vegetables are storage methods for preserving the quality of fruits and vegetables by storing them under low oxygen concentrations or high carbon dioxide concentrations.
However, the present inventor has discovered a problem that, for example, exposing fruits and vegetables to an extremely low oxygen concentration for a long period of time may result in adverse effects such as abnormal ripening, browning of tissues, and accumulation of acetaldehyde and ethanol in the fruits and vegetables.
The above problems can cause discoloration, unpleasant odors, etc., which can cause fruits and vegetables to lose their freshness and make them unsellable.

The problem that one embodiment of the present disclosure aims to solve is to provide a freshness preservation method, packaging material, and freshness-preserving metal component for fruits and vegetables that can effectively preserve the freshness of the fruits and vegetables.

Means for solving the above problems include the following embodiments.
<1> A method for preserving the freshness of fruits and vegetables, comprising: a package production step of producing a package by packaging fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal in a freshness-preserving packaging material; and a storage step of storing the fruits and vegetables while maintaining an oxygen concentration in the range of 0.1 vol% to 12.0 vol% and a carbon dioxide concentration in the range of 3 vol% to 30 vol% inside the package 40 hours after the production of the package, wherein during the storage step, the respiratory quotient of the fruits and vegetables is 0.5 to 2.0.
<2> The method for preserving the freshness of fruits and vegetables according to <1>, wherein the metal material comprises at least one selected from the group consisting of copper, a copper-containing alloy, aluminum, and an aluminum-containing alloy.
<3> The method for preserving the freshness of fruits and vegetables according to <1> or <2>, wherein the mass (g) of the metal material relative to the mass (g) of the fruits and vegetables is 0.00005 to 0.02000.
<4> The method for preserving the freshness of fruits and vegetables according to any one of <1> to <3>, wherein the mass (g) of the metal material relative to the volume (cm ³ ) of the packaging body is 0.1× ^{10 −4} to 10.0×10 ⁻⁴ .
<5> The method for preserving the freshness of fruits and vegetables according to any one of <1> to <4>, wherein the ratio of the surface area (cm ² ) of the metal material to the volume (cm ³ ) of the packaging body is 0.5×10 ⁻⁴ to 15.0×10 ⁻³ .
<6> The method for preserving the freshness of fruits and vegetables described in any one of <1> to <5>, wherein the package production step is a step of packaging the fruits and vegetables and a freshness-preserving metal component including a metal material containing at least one of the divalent metal and the trivalent metal in the freshness-preserving packaging material to produce the package.
<7> The method for preserving the freshness of fruits and vegetables described in <6>, wherein the freshness-preserving metal component includes a metal layer made of the metal material on an outermost surface, and the surface area of the metal layer is 70% to 100% of the total surface area of the freshness-preserving metal component.
<8> The method for preserving the freshness of fruits and vegetables according to <6> or <7>, wherein at least a portion of the freshness-preserving metal member is in contact with the fruits and vegetables.
<9> The method for preserving the freshness of fruits and vegetables according to any ^one of <1> to <8>, wherein the freshness-preserving packaging material has a carbon dioxide permeability of 4,500 cm ³ /m ² ·day ·atm to 45,000 ^{cm 3 /} m ² ·day ·atm and an oxygen permeability of 1,000 cm ³ /m ² ·day ·atm to 30,000 cm 3 /m 2 ·day ·atm.
<10> The method for preserving the freshness of fruits and vegetables according to any one of <1> to <9>, wherein the freshness-preserving packaging material is a polymer film containing at least one selected from the group consisting of polyethylene, polypropylene, polymethylpentene, and polyethylene terephthalate.
<11> The method for preserving the freshness of fruits and vegetables according to any one of <1> to <10>, wherein the freshness-preserving packaging material has one or less holes having a maximum diameter of 50 μm or more per 1 ^m2 .
<12> A package comprising: fruits or vegetables; a metal material containing at least one of a divalent metal and a trivalent metal; and a freshness-preserving packaging material, wherein the fruits or vegetables and the metal material are packaged in the freshness-preserving packaging material.
<13> A freshness-preserving metal component comprising a metal material containing at least one of a divalent metal and a trivalent metal.
<14> The freshness-preserving metal member according to <13>, which is a freshness-preserving display member for fruits and vegetables, comprising a metal layer made of the metal material and an adhesive layer provided on one side of the metal layer.
<15> The freshness-preserving metal component according to <13>, which is a decorative component for fruits and vegetables.

According to one embodiment of the present disclosure, it is possible to provide a freshness preservation method for fruits and vegetables, a packaging body, and a freshness-preserving metal component that can effectively preserve the freshness of fruits and vegetables.

In the present disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values before and after "to" as the minimum and maximum values, respectively.
In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced by the upper or lower limit value of another numerical range described in stages, or may be replaced by a value shown in the examples.
In this disclosure, when a material contains multiple substances corresponding to each component, the amount of each component in the material means the total amount of the multiple substances present in the material, unless otherwise specified.

<How to keep fruits and vegetables fresh>
The method for preserving the freshness of fruits and vegetables of the present disclosure includes a package manufacturing process for manufacturing a package by packaging fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal in a freshness-preserving packaging material;
and a storage step of storing the fruits and vegetables in the package 40 hours after the production of the package while maintaining an oxygen concentration in the range of 0.1% by volume to 12.0% by volume and a carbon dioxide concentration in the range of 3% by volume to 30% by volume,
During storage, the respiratory quotient of fruits and vegetables is 0.5 to 2.0.

The method for preserving the freshness of fruits and vegetables of the present disclosure includes the above-mentioned configuration, and is thereby able to effectively preserve the freshness of fruits and vegetables.
In the method for preserving the freshness of fruits and vegetables disclosed herein, the package produced in the package production process is stored in a low-oxygen, high-carbon dioxide state in the storage process. Furthermore, in the storage process, the respiratory quotient of the fruits and vegetables is 0.5 to 2.0 (i.e., aerobic respiration), so that discoloration, occurrence of unpleasant odors, etc. can be suppressed. As a result, the freshness of the fruits and vegetables can be well preserved.
Each step will be described below.

<Package manufacturing process>
The package manufacturing process in the present disclosure is a process of manufacturing a package by packaging fruits or vegetables and a metal material containing at least one of a divalent metal and a trivalent metal in a freshness-preserving packaging material.

By packaging fruits and vegetables in freshness-preserving packaging materials, the carbon dioxide and oxygen concentrations inside the package can be adjusted in a well-balanced manner, suppressing the respiration rate of the fruits and vegetables. As a result, the freshness of the fruits and vegetables can be well-preserved for a long period of time.

(Fruits and vegetables)
Fruits and vegetables include fruits and vegetables.
Examples of fruits include strawberries, mangoes, avocados, quince, pears, apples, American cherries, cherries, plums, apricots, plums, peaches, figs, persimmons, kiwi fruit, cranberries, grapes, blueberries, blackberries, raspberries, loquats, bayberries, watermelons, melons, papayas, passion fruit, pineapples, and citrus fruits, with strawberries being particularly preferred.
Examples of vegetables include spinach, lettuce, cabbage, Chinese cabbage, komatsuna, bok choy, osmanthus leaf, mizuna, parsley, celery, Japanese parsley, green onion, tomato, cherry tomato, eggplant, pumpkin, bell pepper, cucumber, myoga, cauliflower, broccoli, chrysanthemum, onion, asparagus, burdock, butterbur, burdock, carrot, daikon radish, radish, turnip, Chinese yam, mountain yam, potato, sweet potato, taro, lotus root, okra, pumpkin, bitter melon, corn, edamame, snow peas, broad beans, and green beans.

Among the fruits and vegetables listed above, strawberries, mangoes, and avocados are preferred, with strawberries being more preferred.

(metallic material)
The metallic material in the present disclosure includes at least one of a divalent metal and a trivalent metal.
By including the metal material of the present disclosure in the packaging body of the present disclosure, discoloration and occurrence of unpleasant odors can be effectively suppressed even when fruits and vegetables are stored in a low-oxygen, high-carbon dioxide condition as in the storage process of the present disclosure, and as a result, the freshness of the fruits and vegetables can be effectively maintained.
The metallic material in the present disclosure may include at least one selected from the group consisting of divalent metals, trivalent metals, and alloys thereof.

The divalent metal can be used without any particular limitation.
The divalent metal is preferably copper, iron, nickel, manganese, tungsten, titanium, silver or zinc, more preferably copper, iron, tungsten or silver, and even more preferably copper.

The trivalent metal can be used without any particular limitation.
The trivalent metal is preferably aluminum, palladium, manganese, iron or titanium, more preferably aluminum or iron, and even more preferably aluminum.

As alloys containing divalent metals, brass (Cu 60-70%, Zn 30-40%), copper-tungsten (W 70%, Cu 30%) or gilding metal (Cu 85%, Zn 15%) are preferred, with brass (Cu 60-70%, Zn 30-40%) or copper-tungsten (W 70%, Cu 30%) being more preferred.

A preferred alloy containing a trivalent metal is aluminum-magnesium (97% Al, 3% Mg).

In the method for preserving the freshness of fruits and vegetables disclosed herein, it is preferable that the metal material contains at least one selected from the group consisting of copper, a copper-containing alloy, aluminum, and an aluminum-containing alloy.

(Freshness-preserving metal parts)
The freshness-preserving metal component in the present disclosure includes a metal material containing at least one of a divalent metal and a trivalent metal.
The packaging body in the present disclosure includes fresh produce, a metal material containing at least one of a divalent metal and a trivalent metal, and a freshness-preserving packaging material, wherein the fresh produce and the metal material are packaged in the freshness-preserving packaging material.
In the package, the metallic material is preferably present as a freshness-preserving metallic component comprising a metallic material containing at least one of a divalent metal and a trivalent metal.

The package manufacturing process is preferably a process of manufacturing a package by packaging fruits or vegetables and a freshness-preserving metal component containing a metal material containing at least one of a divalent metal and a trivalent metal in a freshness-preserving packaging component.

Specific examples of the freshness-preserving metal components include display components for preserving the freshness of fruits and vegetables, which are used to display the specifications of fruits and vegetables, and decorative components for decorating fruits and vegetables.

[Indication material for preserving freshness of fruits and vegetables]
The display component for preserving the freshness of fruits and vegetables according to the present disclosure includes the freshness-preserving metal component according to the present disclosure, and the freshness-preserving metal component is in the form of a sheet with an adhesive applied to one side.
Examples of the display member for maintaining the freshness of fruits and vegetables include labels, stickers, tapes, and the like.

[Decorative materials for fruit and vegetable display]
The fruit and vegetable decorative member of the present disclosure includes the freshness-preserving metal member of the present disclosure.
Examples of fruit and vegetable decorative members include cushioning materials, wires, ribbons, and the like.

The freshness-preserving metal components of the present disclosure can be used in a variety of ways without particular limitation.
For example, the freshness-preserving metal component of the present disclosure may be an adhesive sticker, a label, a tag, a ribbon, wire, a cushioning material (e.g., a fruit cap), a fruit bag, a fruit pack, a sheet, a foil, a rivet, a cable tie, a tape, a twist tie, or a clip.

From the viewpoint of effectively maintaining the freshness of fruits and vegetables, the freshness-preserving metal component includes a metal layer made of a metal material on the outermost surface, and the surface area of the metal layer is preferably 70% to 100%, more preferably 75% to 99%, and even more preferably 80% to 95% of the total surface area of the freshness-preserving metal component.

In the method of preserving the freshness of fruits and vegetables disclosed herein, it is preferable that at least a portion of the freshness-preserving metal component is in contact with the fruits and vegetables in order to effectively preserve the freshness of the fruits and vegetables.

(Freshness-preserving packaging materials)
In the package manufacturing process of the present disclosure, fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal are packaged in a freshness-preserving packaging material to manufacture a package.
There are no particular restrictions on the freshness-preserving packaging material, so long as it is a freshness-preserving packaging material that can maintain the oxygen concentration in the range of 0.1% by volume to 12.0% by volume and the carbon dioxide concentration in the range of 3% by volume to 30% by volume within the package 40 hours after the package is manufactured during the storage process described below.
Examples of freshness-preserving packaging materials include films.

In the present disclosure, from the viewpoint of suppressing the respiration rate of fruits and vegetables and adjusting the carbon dioxide and oxygen concentrations in the package in a well-balanced manner, it is preferable that the freshness-preserving packaging material has a carbon dioxide permeability and an oxygen permeability within a specific range.

(Carbon dioxide permeability)
The freshness-preserving packaging material in the present disclosure preferably has a carbon dioxide permeability of 4,500 cm ³ /m ² ·day ·atm to 45,000 ^{cm 3} /m ² ·day ·atm, more preferably 7,000 cm ³ /m ² ·day ·atm to 40,000 cm ³ /m ² ·day ·atm, and even more preferably 10,000 cm ³ /m ² ·day ·atm to 35,000 cm ³ /m ² ·day ·atm.
The carbon dioxide permeability is measured at 23° C. and 0% RH.
By having the carbon dioxide permeability within the above range, the carbon dioxide that has increased inside the package due to respiration of the fruit or vegetable is released to the outside, and the carbon dioxide concentration is appropriately adjusted, thereby making it possible to satisfactorily maintain the freshness of the fruit or vegetable.

The carbon dioxide permeability of the freshness-preserving packaging material is a value measured using a differential pressure gas permeability measuring device (GTR-30XA, GTR Tech Co., Ltd.) under an environment of 23°C and 0% RH, with 100% test gas (CO ₂ ) and a test area of 15.2 cm ² .

(Oxygen permeability)
The freshness-preserving packaging material in the present disclosure preferably has an oxygen permeability of 1000 cm ³ /m ² ·day ·atm to 30,000 ^{cm 3} /m ² ·day ·atm, more preferably 8,000 cm ³ /m ² ·day ·atm to 25,000 ^{cm 3} /m ² ·day ·atm, and even more preferably 10,000 cm ³ /m ² ·day ·atm to 20,000 cm ³ /m ² ·day ·atm.
The oxygen transmission rate of the freshness-preserving packaging material means the oxygen transmission rate at 23° C. and 0% RH.
By setting the oxygen permeability within the above range, the oxygen concentration inside the package can be maintained at a low level, suppressing respiration of the fruits and vegetables. Also, oxygen lost due to respiration is supplied from the outside, maintaining the minimum necessary oxygen concentration.
Furthermore, by ensuring that the oxygen permeability is within the above range, the freshness of fruits and vegetables can be well maintained.

The oxygen permeability is a value measured using a differential pressure gas permeability measuring device (GTR-30XA, GTR Tech Co., Ltd.) under an environment of 23° C. and 0% RH, with 100% test gas (O ₂ ) and a test area of 15.2 cm ² .

The freshness-preserving packaging member preferably has a carbon dioxide permeability of 4,500 cm ³ /m ² ·day·atm to 45,000 ^{cm 3} /m ² ·day·atm and an oxygen permeability of 1,000 cm ³ /m ² ·day·atm to 30,000 ^{cm 3} /m ² ·day·atm.

From the viewpoint of preventing the intrusion of bacteria and the like from the outside, the freshness-preserving packaging material in the present disclosure preferably exhibits excellent gas permeability even without pores. In addition, the fewer the number of pores that may cause the intrusion of bacteria and the like from the outside, the more preferable.
Specifically, it is preferred that the freshness-preserving packaging material have no more than one hole with a maximum diameter of 50 μm or more per square ^meter .

The material of the freshness-preserving packaging member in the present disclosure is not particularly limited, but examples thereof include α-olefin copolymers.
Examples of the α-olefin copolymer include polyethylene, polypropylene, polymethylpentene, and polyethylene terephthalate.

In one embodiment of the present disclosure, the freshness-preserving packaging material contains a polymer having structural units derived from 4-methyl-1-pentene (hereinafter also referred to as a 4-methyl-1-pentene polymer). 4-methyl-1-pentene polymers have a bulkier molecular structure than other polyolefins such as polyethylene and polypropylene, and therefore have a lower density and exhibit high gas permeability. For this reason, they can be suitably used as a material for freshness-preserving packaging materials.

The 4-methyl-1-pentene polymer may be a homopolymer consisting only of structural units derived from 4-methyl-1-pentene, or a copolymer containing structural units derived from 4-methyl-1-pentene and structural units derived from a component other than 4-methyl-1-pentene.
By changing the ratio of constituent units derived from 4-methyl-1-pentene to constituent units derived from components other than 4-methyl-1-pentene, the carbon dioxide permeability and oxygen permeability of the freshness-preserving packaging material can be adjusted to the desired range.

When the 4-methyl-1-pentene polymer is a copolymer containing structural units derived from a component other than 4-methyl-1-pentene, the component other than 4-methyl-1-pentene is preferably ethylene or an α-olefin having 3 to 20 carbon atoms (excluding 4-methyl-1-pentene).

Specific examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1-octadecene, and 1-eicosene.
Among these, propylene is preferred from the viewpoint of availability, and 1-butene is preferred from the viewpoint of imparting low-temperature heat sealability to the freshness-preserving packaging material.

The method for synthesizing the 4-methyl-1-pentene polymer is not particularly limited, and known methods can be used. When using a component other than 4-methyl-1-pentene when synthesizing the 4-methyl-1-pentene polymer, only one type or two or more types of the component other than 4-methyl-1-pentene may be used.

The freshness-preserving packaging material may contain a 4-methyl-1-pentene polymer and a polymer other than a 4-methyl-1-pentene polymer.
By changing the blend ratio of the 4-methyl-1-pentene polymer contained in the freshness-preserving packaging material to a polymer other than the 4-methyl-1-pentene polymer, the carbon dioxide permeability and oxygen permeability of the freshness-preserving packaging material can be adjusted to the desired range.

When the freshness-preserving packaging material contains a 4-methyl-1-pentene polymer and a polymer other than a 4-methyl-1-pentene polymer, the polymer other than a 4-methyl-1-pentene polymer is preferably a polyolefin, and preferred examples of the polymer other than a 4-methyl-1-pentene polymer include homopolymers or copolymers of ethylene or α-olefins having 3 to 20 carbon atoms (excluding 4-methyl-1-pentene).

Specific examples of homopolymers or copolymers of α-olefins having 3 to 20 carbon atoms include homopolymers or copolymers of propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1-octadecene, and 1-eicosene.
Among these, from the viewpoint of availability, a propylene homopolymer or copolymer (propylene-based polymer) is preferred, and from the viewpoint of imparting heat sealability at low temperatures to the freshness-preserving packaging material, a 1-butene homopolymer or copolymer (1-butene-based polymer) is preferred.

When the freshness-preserving packaging material contains a 4-methyl-1-pentene polymer and a polymer other than the 4-methyl-1-pentene polymer, the method of blending these polymers is not particularly limited, and known methods can be used. When the freshness-preserving packaging material contains a 4-methyl-1-pentene polymer and a polymer other than the 4-methyl-1-pentene polymer, only one type or two or more types of the polymer other than the 4-methyl-1-pentene polymer may be used.

The freshness-preserving packaging material may have a single-layer structure or a multi-layer structure. For example, while 4-methyl-1-pentene polymers have excellent gas permeability, they tend to have a high melting point and insufficient heat sealability at low temperatures. For this reason, the freshness-preserving packaging material may be a laminate that includes a layer that has excellent heat sealability at low temperatures in addition to a layer that contains a 4-methyl-1-pentene polymer.

The thickness of the freshness-preserving packaging material is not particularly limited. From the standpoint of strength and ease of handling, it may be selected from the range of 10 μm to 100 μm.

The form of the freshness-preserving packaging material is not particularly limited, but it is preferably a polymer film.
The freshness-preserving packaging material is preferably a polymer film containing an α-olefin copolymer.

It is more preferable that the freshness-preserving packaging material is a polymer film containing at least one selected from the group consisting of polyethylene, polypropylene, polymethylpentene, and polyethylene terephthalate.

≪Packaging body≫
The packaging body of the present disclosure includes fresh produce, a metal material containing at least one of a divalent metal and a trivalent metal, and a freshness-preserving packaging material, wherein the fresh produce and the metal material are packaged in the freshness-preserving packaging material.
The package of the present disclosure is produced by packaging fruits or vegetables and a metal material containing at least one of a divalent metal and a trivalent metal in a freshness-preserving packaging material.
By including the above-described configuration, the packaging body of the present disclosure can effectively preserve the freshness of fruits and vegetables.

The shape of the packaging body is not particularly limited. For example, it may be bag-shaped, pack-shaped, box-shaped, etc. As long as the effects of the present disclosure can be obtained, a part of the packaging body may be made of a material other than the freshness-preserving packaging material (for example, a material having a lower carbon dioxide permeability and oxygen permeability than the freshness-preserving packaging material of the present disclosure) as necessary.
From the viewpoint of suppressing the respiration of the fruit or vegetable and maintaining the freshness of the fruit or vegetable well, the package is preferably in a sealed state (substantially free of pores, gaps, etc. communicating with the outside). That is, in the package manufacturing process, it is preferable to manufacture the package by sealing the fruit or vegetable with the above-mentioned freshness-maintaining packaging material.

The volume of the package is not particularly limited.
From the viewpoint of maintaining the freshness of fruits and vegetables well, the volume of the package is preferably 50 cm ³ to 100,000 cm ³ , more preferably 100 cm ³ to 50,000 cm ³ , and even more preferably 1,000 cm ³ to 10,000 cm ³ .

The mass (g) of the metal material relative to the mass (g) of the fruit or vegetable (metal/fruit or vegetable) is preferably 0.00005 to 0.02000, more preferably 0.00010 to 0.01000, and even more preferably 0.00005 to 0.00700.

The mass (g) of the metal material relative to the volume (cm ³ ) of the packaging body is preferably 0.1×10 ⁻⁴ g/cm ³ to 10.0×10 ⁻⁴ g/cm ³ , more preferably 0.3×10 ⁻⁴ g/cm ³ to 8.0×10 ⁻⁴ g/cm ³ , and even more preferably 0.5×10 ⁻⁴ g/cm ³ to 3.0×10 ⁻⁴ g/cm ³ .

The surface area (cm ² ) of the metal material relative to the volume (cm ³ ) of the packaging body is preferably 0.5×10 ⁻⁴ to 15.0×10 ⁻³ , more preferably 0.5×10 ⁻⁴ to 12.0×10 ⁻³ , and even more preferably 0.7×10 ⁻⁴ to 10.0×10 ⁻³ .

<Storage process>
In the storage process of the present disclosure, fruits and vegetables are stored in the package 40 hours after the production of the package while maintaining the oxygen concentration in the range of 0.1 vol.% to 12.0 vol.% and the carbon dioxide concentration in the range of 3 vol.% to 30 vol.%.
During the storage step, the respiration quotient of the fruit or vegetable is 0.5 to 2.0.

The method of preserving the freshness of fruits and vegetables disclosed herein includes a storage step, which allows the package to be stored in a low-oxygen, high-carbon dioxide state (i.e., an anaerobic environment). Furthermore, by keeping the respiratory quotient of the fruits and vegetables at 0.5 to 2.0 (i.e., aerobic respiration) during the storage step, discoloration, unpleasant odors, and the like can be suppressed. As a result, the freshness of the fruits and vegetables can be well preserved.

The oxygen concentration and carbon dioxide concentration in the package 40 hours after the package is manufactured refer to the average oxygen concentration and average carbon dioxide concentration in the package 40 hours after the package is manufactured.

(Oxygen Concentration)
In the storage step, the oxygen concentration in the package is maintained within a range of 0.1% by volume to 12.0% by volume for 40 hours after the package is manufactured.
This provides a low-oxygen environment, which suppresses the respiration rate of the fruits and vegetables, thereby allowing the freshness of the fruits and vegetables to be well maintained.
From the same viewpoint as above, it is preferable that the oxygen concentration inside the package is 0.2% by volume or more.
The oxygen concentration within the package is preferably 10.5% by volume or less, more preferably 6.5% by volume or less, and even more preferably 3.0% by volume or less.

(Carbon dioxide concentration)
In the storage step, the carbon dioxide concentration in the package is maintained within a range of 3% by volume to 30% by volume 40 hours after the production of the package.
This provides a high carbon dioxide environment, which suppresses the respiration rate of the fruits and vegetables, thereby allowing the freshness of the fruits and vegetables to be well maintained.
From the same viewpoint as above, the carbon dioxide concentration in the package is preferably 8% by volume or more, more preferably 11% by volume or more, and even more preferably 15% by volume or more.
In the storage step, the carbon dioxide concentration in the package is preferably 28% by volume or less, and more preferably 25% by volume or less.
The oxygen concentration and carbon dioxide concentration can be measured using, for example, CheckPoint3 (MOCON-DANSENSOR).

In the storage step, the storage temperature is preferably 4°C to 25°C, and more preferably 8°C to 20°C.
Storage temperature refers to the average temperature during the storage process.

According to the method of the present disclosure, it is also possible to store fruits and vegetables for long periods of time.
The storage period may be, for example, 3 days or more, 5 days or more, or 10 days or more.

One example of a method for storing the packaged product in an environment with a predetermined temperature is to store the packaged product in a storage facility with the temperature inside the storage facility set to a predetermined temperature. Storage may involve transportation of the fruit or vegetable product.

(respiratory quotient)
During the storage step, the respiration quotient of the fruit or vegetable is 0.5 to 2.0.
In other words, during the storage process, the fruits and vegetables undergo aerobic respiration, which can prevent discoloration, unpleasant odors, etc. As a result, the freshness of the fruits and vegetables can be well maintained.
In the present disclosure, the respiratory quotient means the volume ratio of carbon dioxide output to the amount of oxygen consumed until nutrients are broken down in a living body and converted into energy in a given period of time.

During the storage process, by setting the respiratory quotient of the fruits and vegetables to 0.5 or more, the fruits and vegetables can consume a large amount of oxygen and maintain a state of aerobic respiration.
From the above viewpoint, the respiration quotient of the fruits and vegetables during the storage step is preferably 0.7 or more, and more preferably 0.9 or more.
During the storage process, by ensuring that the respiratory quotient of the fruits and vegetables is 2.0 or less, oxygen consumption can be ensured and aerobic respiration conditions can be maintained.
From the above viewpoint, the respiration quotient of the fruits and vegetables during the storage step is preferably 1.8 or less, and more preferably 1.6 or less.

The respiratory quotient of fruits and vegetables may be adjusted to a suitable range depending on the type of fruits and vegetables, etc.
For example, the fruit or vegetable is a strawberry, and the respiration quotient of the strawberry is preferably 0.5 to 2.0, and more preferably 0.8 to 1.8.
For example, the fruit or vegetable is a mango, and the respiratory quotient of the mango is preferably 0.5 to 1.5, and more preferably 0.8 to 1.4.

Respiratory quotient is expressed as the ratio of carbon dioxide output to oxygen consumption.
The amount of carbon dioxide emission and the amount of oxygen consumption can be measured by measuring the change in the oxygen concentration and the carbon dioxide concentration in the package, and can also be calculated by the method described in, for example, the Japanese Journal of Food Low Temperature Preservation, Vol. 22, No. 3, 1996, or the Journal of the Japanese Society of Agricultural and Food Science and Technology, 77(1): 19-27, 2015.
When the Michaelis Menten formula is used, the calculation can be performed, for example, in the following steps.
Specifically, the following applies:

In the simulation of the respiration of fruits and vegetables, a model based on the Michaelis Menten theory (also called the MM model) of (1) to (5) is used as the respiration model.
In addition, the change in respiration rate due to the effect of temperature is modeled using the Arrhenius equation in (6). Therefore, the oxygen consumption rate and carbon dioxide production rate per unit mass of fruit or vegetable are determined by the oxygen concentration, carbon dioxide concentration, and temperature of the gas inside the package.
The parameters of the MM model and the activation energy of the Arrhenius equation are determined based on experimental results. The experimental method is to calculate the respiration rate from the time series changes in oxygen concentration and carbon dioxide concentration measured using a method using a light-transmitting bag.
This calculation may be performed, for example, using Excel, and parameters of the MM model may be identified from the respiration rate in the gas composition of the measured oxygen concentration value and carbon dioxide concentration value.

In the simulation, a Michaelis-Menten (MM) type equation is used as the respiration model. (1) to (5) show each model at the reference temperature. Note that the subscript j in the respiration model equation represents either oxygen or carbon dioxide.
Each formula is shown below.

・Michaelis Menten (MM), Formula 1

r _ref,j : respiration rate at reference temperature [m ³ kg ⁻¹ s ⁻¹ ]
t: time [s]
α _j : Maximum reaction rate [m ³ kg ⁻¹ s ⁻¹ ]
y _O2 : Oxygen concentration φ _j : Michaelis constant [%]

- Michaelis Menten competitive (MMC, competitive inhibition), formula 2

r _ref,j : respiration rate at reference temperature [m ³ kg ⁻¹ s ⁻¹ ]
t: time [s]
α _j : Maximum reaction rate [m ³ kg ⁻¹ s ⁻¹ ]
y _O2 : Oxygen concentration φ _j : Michaelis constant [%]
y _CO2 : Carbon dioxide concentration γ _c,j : Inhibition constant [%]

- Michaelis-Menten uncompetitive (MMU), formula 3

r _ref,j : respiration rate at reference temperature [m ³ kg ⁻¹ s ⁻¹ ]
t: time [s]
α _j : Maximum reaction rate [m ³ kg ⁻¹ s ⁻¹ ]
y _O2 : Oxygen concentration φ _j : Michaelis constant [%]
y _CO2 : Carbon dioxide concentration γ _u,j : Non-inhibition constant [%]

- Michaelis Menten non-competitive (MMN, non-competitive inhibition), formula 4

r _ref,j : respiration rate at reference temperature [m ³ kg ⁻¹ s ⁻¹ ]
t: time [s]
α _j : Maximum reaction rate [m ³ kg ⁻¹ s ⁻¹ ]
y _O2 : Oxygen concentration φ _j : Michaelis constant [%]
y _CO2 : Carbon dioxide concentration γ _n,j : Non-inhibition constant [%]

- Michaelis-Menten combination of competitive and uncompetitive (MMUN, noncompetitive inhibition), formula 5

r _ref,j : respiration rate at reference temperature [m ³ kg ⁻¹ s ⁻¹ ]
t: time [s]
α _j : Maximum reaction rate [m ³ kg ⁻¹ s ⁻¹ ]
y _O2 : Oxygen concentration φ _j : Michaelis constant [%]
y _CO2 : Carbon dioxide concentration γ _c,j : Inhibition constant [%]
t _i : At the initial time, the subscript i is initial.
γ _n,j : non-inhibition constant [%]

- Arrhenius equation (temperature-based respiration model correction), Equation 6

r _j : respiration rate [m ³ kg ⁻¹ s ⁻¹ ], subscript j is either O ₂ or CO ₂ .
t: time [s]
r _ref,j : respiration rate at reference temperature [m ³ kg ⁻¹ s ⁻¹ ]
E _r,j : Activation energy (respiration rate) [Jmol ⁻¹ ]
R: gas constant [JK ⁻¹ mol ⁻¹ ]
T _F : Temperature of fruits and vegetables [K]
T _F,ref : Reference temperature of fruits and vegetables [K]

(Calculation of respiration rate from measured gas concentration), Equation 7,
Using A ₁ , B ₁ , C ₁ , and D ₁ as parameters, the concentration on the left side is fitted to the measured concentration.

Y _O2 : Oxygen concentration [%]
t: time [s]
_A1 :32.47007
_B1 : 0.963
_C1 :0.00017
_D1 :0

The same fitting as for equation 7 is performed for equation 8 to determine A ₁ , B ₁ , C ₁ , D ₁ , A ₂ , B ₂ , C ₂ , and D ₂ .

Y _CO2 : Carbon dioxide concentration [%]
t: time [s]
_A2 : 312.67
_B2 : 0.670826
_C2 :0
_D2 :7.2315503

(Equation 7 time-differentiated), Equation 9
(Equation 8 time-differentiated), Equation 10
Using predetermined _A1 , _B1 , _C1 , _D1 , _A2 , _B2 , _C2 , and _D2 , the amount of change in the oxygen concentration and the carbon dioxide concentration is calculated.

(Equation 9 and equation for calculating respiration rate from gas permeability of packaging material), Equation 11
(Equation 10 and equation for calculating respiration rate from gas permeability of packaging material), Equation 12

_rO2 : Oxygen breathing rate _YO2 : Oxygen concentration [%]
t: time [s]
V _H : Volume of mixed gas in the package [m ³ ]
W _F : Weight of fruits and vegetables [kg], the subscript F stands for fruits and vegetables (i.e. Fruits)
A _p : Surface area of packaging film [m ² ]
Q _O2 : Carbon dioxide permeability [m ³ m ⁻² atm ⁻¹ d ⁻¹ ]
y _O2 : Oxygen concentration L: Thickness of packaging film [m]
ρ _H : Total gas pressure inside the packaging film [Pa], the subscript H is the head space

_rCO2 : Carbon dioxide respiration rate _YCO2 : Carbon dioxide concentration [%]
t: time [s]
V _H : Volume of mixed gas in the package [m ³ ]
W _F : Weight of fruits and vegetables [kg], the subscript F stands for fruits and vegetables (i.e. Fruits)
A _p : Surface area of packaging film [m ² ]
Q _CO2 : Carbon dioxide permeability [m ³ m ⁻² atm ⁻¹ d ⁻¹ ]
L: Thickness of packaging film [m]
ρ _H : Total gas pressure inside the packaging film [Pa], the subscript H is the head space

The respiration rate at each measured concentration value in Equations 11 and 12 is fitted to the respiration rate of the respiration model, and the parameters of each MM type model are identified.
The respiratory quotient is defined as the carbon dioxide respiration rate, _rCO2 , divided by the oxygen respiration rate, _rO2 .

Embodiments of the present disclosure will be described in detail below with reference to examples. Note that the invention of the present disclosure is not limited in any way to the description of these examples.

Details of the members used in this embodiment are as follows.
[Freshness-preserving metal components]
Copper ribbon: Nilaco Corporation, brand 110607, width 3.0 mm, thickness 0.1 mm, length 2 cm
Surface area of metal material: 1.2 ^cm2
Surface area of metal layer/total surface area of freshness-preserving metal component: 1.2 ^cm2
Aluminum foil, manufactured by Daiso Industries Co., Ltd., brand F030, aluminum foil, thickness 11 μm, size 7 cm square, surface area of metal material: 98 ^cm2
Surface area of metal layer/total surface area of freshness-preserving metal component: 98 ^cm2
Copper alloy, manufactured by Nilaco Corporation, brand number 531109, diameter 1 mm, length 16 cm, surface area of metal material: 5 ^cm3
Surface area of metal layer / total surface area of freshness-preserving metal component: 5

[Freshness-preserving packaging materials]
・Stretched polypropylene film A
Mitsui Chemicals Tocello Co., Ltd. Brand Spash (NFHC-SP) Thickness 30 μm
・Stretched polypropylene film B
Mitsui Chemicals Tocello Co., Ltd. Brand Spash (NFHC-SP) Thickness 30 μm
・Stretched polypropylene film C
Mitsui Chemicals, Inc. Adfresh (M20) Thickness: 40 μm
・4-Methyl-1-pentene film (4M1P film)
A laminate comprising, in this order, a surface layer (outside the bag) containing 90 parts by mass of a propylene polymer and 10 parts by mass of a 1-butene polymer, an intermediate layer containing 20 parts by mass of a 4-methyl-1-pentene polymer, 56 parts by mass of a propylene polymer and 24 parts by mass of a 1-butene polymer, and a surface layer (inside the bag) containing 90 parts by mass of a propylene polymer and 10 parts by mass of a 1-butene polymer, and the thicknesses of the surface layer (outside the bag), intermediate layer and surface layer (inside the bag) are 8 μm, 24 μm and 8 μm, respectively (total thickness of 40 μm).

[Measurement and Evaluation]
(carbon dioxide concentration, oxygen concentration)
Measurement was performed using CheckPoint3 (MOCON-DANSENSOR).

(respiratory quotient)
The respiratory quotient was measured by the method described above in the section (Respiratory quotient).

(Acetaldehyde concentration)
The acetaldehyde concentration was measured using a gas chromatograph (manufactured by Nissha FIS, model: SGEA-P3-C) that uses a semiconductor gas sensor. The measurement method was a manual gas injection method using a syringe (sample amount: 5 cc/time), and the measurement graph and the measurement target gas concentration were displayed using the SGC measurement analysis software.

(Discoloration ratio)
Images of the fruits and vegetables before and after storage were taken from above, and the discoloration ratio was measured using a visual analyzer IRIS VA400 (manufactured by Alphamos) to determine the ratio [%] of the following color numbers to the total area of the fruits and vegetables in the captured images.

Regarding the evaluation of red-black coloring of strawberries, a visual analyzer IRIS VA400 (manufactured by Alpha Moss Japan Co., Ltd.) was used to evaluate the ratio of color number "1296" (R: 88, G: 24, B: 8), color number "1297" (R: 88, G: 24, B: 24), color number "1313" (R: 88, G: 40, B: 24), color number "1568" (R: 104, G: 40, B: 8), color number "1808" (R: 120, G: 24, B: 8), color number "1840" (R: 120, G: 56, B: 8), color number "2096" (R: 136, G: 56, B: 8), and color number "2098" (R: 136, G: 56, B: 40).
The color numbers "1296", "1297", "1313", "1568", "1808", "1840", "2096", and "2098" indicate reddish black and discolored areas of the strawberry. The larger the sum of the above ratios, the larger the proportion of discolored areas of the strawberry.

Regarding the evaluation of the black-red coloring of mangoes, a visual analyzer IRIS VA400 (manufactured by Alpha Moss Japan Co., Ltd.) was used to evaluate the percentages of color number "2099" (R: 136, G: 56, B: 56), color number "2116" (R: 136, G: 72, B: 72), and color number "2370" (R: 152, G: 72, B: 40).
The color numbers "2099", "2116" and "2370" indicate a black-red color and represent discolored areas of the mango. The larger the sum of the above ratios, the larger the proportion of discolored areas of the mango.

The green coloring of the avocados was evaluated using a visual analyzer IRIS VA400 (manufactured by Alpha Moss Japan Co., Ltd.) to evaluate the proportion of color number "1091" (R: 72, G: 72, B: 56).
The color number "1091" indicates the color green, which represents the portion of the avocado other than the discolored portion. The larger the sum of the above ratios, the smaller the proportion of the discolored portion of the avocado.

The color change ratio was calculated from the obtained color ratio.
Change in discoloration ratio of strawberry = (discoloration ratio of strawberry image after storage) - (discoloration ratio of strawberry image before storage) [%]
Color numbers: "1296" (R:88, G:24, B:8), "1297" (R:88, G:24, B:24), "1313" (R:88, G:40, B:24), "1568" (R:104, G:40, B:8), "1808" (R:120, G:24, B:8), "1840" (R:120, G:56, B:80), "2096" (R:136, G:56, B:8), and "2098" (R:136, G:56, B:40)
A larger change in the discoloration ratio means a larger increase in the discolored area.

Change in discoloration ratio of mango = (discoloration ratio of mango image after storage) - (discoloration ratio of mango image before storage) [%]
Color number: "2099" (R:136, G:56, B:56), color number "2116" (R:136, G:72, B:72), color number "2370" (R:152, G:72, B:40)
A larger change in the discoloration ratio means a larger increase in the discolored area.

Change in discoloration rate of avocado = (discoloration rate of avocado image after storage) - (discoloration rate of avocado image before storage) [%]
Color number "1091" (R: 72, G: 72, B: 56)
A larger change in the discoloration ratio means a larger increase in the discolored area.
That is, in the case of avocado, a larger change in the discoloration ratio means a larger reduction in the amount of green part, and a smaller change in the discoloration ratio means that the green part is maintained.

(Taste index)
The taste index was calculated by assigning a score for each taste to all fruits and vegetables packaged in the package according to Table 1 below, and adding up the scores for all fruits and vegetables to calculate the index for each taste. Within the range of scores for each taste, the best score is 3.

(Sensory evaluation)
～Appearance～
The appearance of the fruits and vegetables was evaluated by the following method.
・ΔE * ab
Using a visual analyzer IRIS VA400 (manufactured by Alphamos), photographs of the fruits and vegetables were taken before and after the experiment, and the L*a*b* information for each was extracted. The color difference, ΔE*ab, was calculated using the following formula.
It can be said that the smaller the ΔE*ab value, the less the color change.

Using the obtained ΔE*ab, the appearance of the fruits and vegetables was evaluated according to the following criteria.
Of the following criteria, 1 is the best rank.
〔standard〕
1: No blackening.
2: Not entirely, but some areas were discolored black.
3: The whole was discolored black.

～Taste～
The taste was evaluated according to the following criteria.
Of the following criteria, 1 is the best rank.
〔standard〕
1: Delicious with a rich aroma.
2: The aroma is mild and the taste is somewhat delicious.
3: It smells fermented and tastes bad.

<Examples 1 to 3, Comparative Example 1>
[Storage test implementation]
To carry out the storage test, strawberries (variety: Tochiotome, mass: 276 g, number of pieces: 17) were prepared. Also, bags were made using the freshness-preserving packaging materials shown in Table 2.

[Packaging manufacturing process]
Strawberries and the freshness-preserving metal member shown in Table 2 (total mass: mass shown in Table 2) were placed in a bag made using the freshness-preserving packaging member shown in Table 2. The top of the bag was then tied with a cable tie to produce a package.
The volume of the package was 1500 ^cm3 .
The mass of strawberries per unit volume in the package is 0.184 g/ ^cm3 .

[Storage process]
The resulting packages were placed on pallets and stored in a storage cabinet at the average temperature listed in Table 2 for 3 days.
During storage, at least a portion of the freshness-preserving metal member is in contact with the fruit or vegetable.
The results of various evaluations and measurements are shown in Table 2.

As shown in Table 2, an example using a freshness preservation method for fruits and vegetables, which includes a package manufacturing process for manufacturing a package by packaging fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal in a freshness preserving packaging member, and a storage process for storing the fruits and vegetables in the package 40 hours after the production of the package while maintaining an oxygen concentration in the range of 0.1% by volume to 12.0% by volume and a carbon dioxide concentration in the range of 3% by volume to 30% by volume, and in which the respiratory quotient of the fruits and vegetables in the storage process is 0.5 to 2.0, showed low discoloration rate change, high taste index, and excellent appearance and taste in a sensory evaluation. Therefore, the freshness of the fruits and vegetables could be well preserved.
In addition, since the acetaldehyde concentration is low in the examples, it is believed that the unpleasant odor is suppressed.
On the other hand, Comparative Example 1, which did not contain any metal material, had a high discoloration rate change, a low taste index, and was poor in appearance and taste in the sensory evaluation. Therefore, the freshness of fruits and vegetables could not be well maintained.
In addition, it is considered that the acetaldehyde concentration in Comparative Example 1 is high, and therefore the unpleasant odor is not suppressed.

<Example 4, Comparative Example 2>
[Storage test implementation]
To carry out the storage test, mangoes (variety: Irwin, mass: 460 g, number of pieces: 1) were prepared. Also, bags were made using the freshness-preserving packaging materials shown in Table 3.

[Packaging manufacturing process]
The mangoes were placed in a bag made using the freshness-preserving packaging material described in Table 3 above.
Aluminum foil was inserted as a freshness-preserving material. The top of the bag was then tied with a cable tie, and the mangoes were packed into the bag to produce a package.
The volume of the package was 500 ^cm3 .
The mass of mango per unit volume in the package is 0.92 g/ ^cm3 .

[Storage process]
The resulting packages were placed on pallets and stored in a storage cabinet at the average temperature listed in Table 3 for 8 days.
During storage, at least a portion of the freshness-preserving metal member is in contact with the fruit or vegetable.
The results of various evaluations and measurements are shown in Table 3.

As shown in Table 3, an example using a freshness preservation method for fruits and vegetables, which includes a package manufacturing step of manufacturing a package by packaging fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal in a freshness preserving packaging member, and a storage step of storing the fruits and vegetables in the package 40 hours after the production of the package while maintaining an oxygen concentration in the range of 0.1% by volume to 12.0% by volume and a carbon dioxide concentration in the range of 3% by volume to 30% by volume, and in which the respiratory quotient of the fruits and vegetables in the storage step is 0.5 to 2.0, showed low change in discoloration ratio and excellent appearance and taste in a sensory evaluation. Therefore, the freshness of the fruits and vegetables could be well preserved.
In addition, since the acetaldehyde concentration is low in the examples, it is believed that the unpleasant odor is suppressed.
On the other hand, Comparative Example 2, which did not contain any metal material, had a high discoloration rate and was poor in appearance and taste in the sensory evaluation. Therefore, the freshness of fruits and vegetables could not be well preserved.
In addition, since the acetaldehyde concentration in Comparative Example 3 is high, it is considered that the unpleasant odor is not suppressed.

<Example 5, Comparative Example 3>
[Storage test implementation]
To carry out the storage test, an avocado (mass: 170 g, number of pieces) was prepared. Also, a bag was made using the freshness-preserving packaging material shown in Table 4.

[Packaging manufacturing process]
The prepared avocados and a copper ribbon as a freshness preserving material were placed in a bag made using the freshness preserving packaging material described in Table 4. The top of the bag was then tied with a cable tie, and the avocados were packaged to produce a package.
The volume of the package was 600 ^cm3 .
The mass of avocado per unit volume in the package is 0.283 g/ ^cm3 .

[Storage process]
The resulting packages were placed on pallets and stored in a storage cabinet at the average temperatures listed in Table 4 for 6 days.
During storage, at least a portion of the freshness-preserving metal member is in contact with the fruit or vegetable.
The results of various evaluations and measurements are shown in Table 4.

As shown in Table 4, the examples using the freshness preservation method for fruits and vegetables, which includes a package manufacturing process for manufacturing a package by packaging fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal in a freshness preserving packaging member, and a storage process for storing the fruits and vegetables in the package 40 hours after the production of the package while maintaining an oxygen concentration in the range of 0.1% by volume to 12.0% by volume and a carbon dioxide concentration in the range of 3% by volume to 30% by volume, and in which the respiratory quotient of the fruits and vegetables in the storage process is 0.5 to 2.0, showed low change in discoloration ratio and excellent appearance and taste in a sensory evaluation. Therefore, the freshness of the fruits and vegetables could be well preserved.
In addition, since the acetaldehyde concentration is low in the examples, it is believed that the unpleasant odor is suppressed.
On the other hand, Comparative Example 3, which did not contain any metal material, had a high discoloration rate and was poor in appearance and taste in the sensory evaluation. Therefore, the freshness of fruits and vegetables could not be well preserved.
In addition, since the acetaldehyde concentration in Comparative Example 3 is high, it is considered that the unpleasant odor is not suppressed.

Claims (17)

a package manufacturing process for manufacturing a package by packaging fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal with a freshness-preserving packaging material;
a storage step of storing the fruits and vegetables in the package 40 hours after production of the package while maintaining an oxygen concentration in the range of 0.1% by volume to 12.0% by volume and a carbon dioxide concentration in the range of 3% by volume to 30% by volume;
Including,
In the storage step, the respiration quotient of the fruits and vegetables is 0.5 to 2.0;
The mass (g) of the metal material relative to the mass (g) of the fruit or vegetable is 0.00005 to 0.02000,
the surface area (cm ² ) of the metal material relative to the volume (cm ³ ) of the packaging body is 0.5×10 ⁻⁴ to 15.0×10 ⁻³ ;
A method for preserving the freshness of fruits and vegetables, wherein the divalent metal is at least one selected from the group consisting of copper, iron, nickel, manganese, tungsten, titanium, silver, and zinc, and the trivalent metal is at least one selected from the group consisting of aluminum, palladium, manganese, iron, and titanium . a package manufacturing process for manufacturing a package by packaging fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal with a freshness-preserving packaging material;
a storage step of storing the fruits and vegetables in the package 40 hours after production of the package while maintaining an oxygen concentration in the range of 0.1% by volume to 12.0% by volume and a carbon dioxide concentration in the range of 3% by volume to 30% by volume;
Including,
In the storage step, the respiration quotient of the fruits and vegetables is 0.5 to 2.0;
The mass (g) of the metal material relative to the mass (g) of the fruit or vegetable is 0.00005 to 0.02000,
The package manufacturing process is a process of manufacturing the package by packaging the fruit or vegetable and a freshness-preserving metal member containing a metal material containing at least one of the divalent metal and the trivalent metal with the freshness-preserving packaging material,
The freshness-preserving metal component includes a metal layer made of the metal material on the outermost surface, and the surface area of the metal layer is 70% to 100% of the total surface area of the freshness-preserving metal component;
A method for preserving the freshness of fruits and vegetables, wherein the divalent metal is at least one selected from the group consisting of copper, iron, nickel, manganese, tungsten, titanium, silver, and zinc, and the trivalent metal is at least one selected from the group consisting of aluminum, palladium, manganese, iron, and titanium . The mass (g) of the metal material relative to the volume (cm ³ ) of the package is 0.1×10 ⁻⁴
The method for preserving the freshness of fruits and vegetables according to claim 1 or 2, wherein the freshness preservation rate is 10.0×10 ⁻⁴ or less. The method for preserving the freshness of fruits and vegetables according to claim 2 , wherein at least a portion of the freshness-preserving metal member is in contact with the fruits and vegetables. The method for preserving the freshness of fruits and vegetables according to any ^{one of claims 1 to 4, wherein the freshness-preserving packaging material has a carbon dioxide permeability of 4,500 cm 3 /m 2 · day ·} atm to 45,000 cm ³ /m ² ·day ·atm and an oxygen permeability of 1,000 cm ³ /m ² ·day ·atm to 30,000 cm 3 /m 2 ·day ·atm. The freshness-preserving packaging material is a polymer film containing at least one selected from the group consisting of polyethylene, polypropylene, polymethylpentene, and polyethylene terephthalate. The method for preserving the freshness of fruits and vegetables according to any one of claims 1 to 5 . The method for preserving the freshness of fruits and vegetables according to any one of claims 1 to 6 , wherein the freshness-preserving packaging material has one or less pores having a maximum diameter of 50 μm or more per 1 ^m2 . a package manufacturing process for manufacturing a package by packaging fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal with a freshness-preserving packaging material;
a storage step of storing the fruits and vegetables in the package 40 hours after production of the package while maintaining an oxygen concentration in the range of 0.1% by volume to 12.0% by volume and a carbon dioxide concentration in the range of 3% by volume to 30% by volume;
Including,
In the storage step, the respiration quotient of the fruits and vegetables is 0.5 to 2.0;
the mass (g) of the metal material relative to the volume (cm ³ ) of the packaging body is 0.1×10 ⁻⁴ to 10.0×10 ⁻⁴ ,
the surface area (cm ² ) of the metal material relative to the volume (cm ³ ) of the packaging body is 0.5×10 ⁻⁴ to 15.0×10 ⁻³ ;
A method for preserving the freshness of fruits and vegetables, wherein the divalent metal is at least one selected from the group consisting of copper, iron, nickel, manganese, tungsten, titanium, silver, and zinc, and the trivalent metal is at least one selected from the group consisting of aluminum, palladium, manganese, iron, and titanium . a package manufacturing process for manufacturing a package by packaging fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal with a freshness-preserving packaging material;
a storage step of storing the fruits and vegetables in the package 40 hours after production of the package while maintaining an oxygen concentration in the range of 0.1% by volume to 12.0% by volume and a carbon dioxide concentration in the range of 3% by volume to 30% by volume;
Including,
In the storage step, the respiration quotient of the fruits and vegetables is 0.5 to 2.0;
the mass (g) of the metal material relative to the volume (cm ³ ) of the packaging body is 0.1×10 ⁻⁴ to 10.0×10 ⁻⁴ ,
The package manufacturing process is a process of manufacturing the package by packaging the fruit or vegetable and a freshness-preserving metal member containing a metal material containing at least one of the divalent metal and the trivalent metal with the freshness-preserving packaging material,
The freshness-preserving metal component includes a metal layer made of the metal material on the outermost surface, and the surface area of the metal layer is 70% to 100% of the total surface area of the freshness-preserving metal component;
A method for preserving the freshness of fruits and vegetables, wherein the divalent metal is at least one selected from the group consisting of copper, iron, nickel, manganese, tungsten, titanium, silver, and zinc, and the trivalent metal is at least one selected from the group consisting of aluminum, palladium, manganese, iron, and titanium . a package manufacturing process for manufacturing a package by packaging fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal with a freshness-preserving packaging material;
a storage step of storing the fruits and vegetables in the package 40 hours after production of the package while maintaining an oxygen concentration in the range of 0.1% by volume to 12.0% by volume and a carbon dioxide concentration in the range of 3% by volume to 30% by volume;
Including,
In the storage step, the respiration quotient of the fruits and vegetables is 0.5 to 2.0;
The fruit or vegetable is a strawberry, a mango, or an avocado;
the surface area (cm ² ) of the metal material relative to the volume (cm ³ ) of the packaging body is 0.5×10 ⁻⁴ to 15.0×10 ⁻³ ;
A method for preserving the freshness of fruits and vegetables, wherein the divalent metal is at least one selected from the group consisting of copper, iron, nickel, manganese, tungsten, titanium, silver, and zinc, and the trivalent metal is at least one selected from the group consisting of aluminum, palladium, manganese, iron, and titanium . a package manufacturing process for manufacturing a package by packaging fruits and vegetables and a metal material containing at least one of a divalent metal and a trivalent metal with a freshness-preserving packaging material;
a storage step of storing the fruits and vegetables in the package 40 hours after production of the package while maintaining an oxygen concentration in the range of 0.1% by volume to 12.0% by volume and a carbon dioxide concentration in the range of 3% by volume to 30% by volume;
Including,
In the storage step, the respiration quotient of the fruits and vegetables is 0.5 to 2.0;
The fruit or vegetable is a strawberry, a mango, or an avocado;
The package manufacturing process is a process of manufacturing the package by packaging the fruit or vegetable and a freshness-preserving metal member containing a metal material containing at least one of the divalent metal and the trivalent metal with the freshness-preserving packaging material,
The freshness-preserving metal component includes a metal layer made of the metal material on the outermost surface, and the surface area of the metal layer is 70% to 100% of the total surface area of the freshness-preserving metal component;
A method for preserving the freshness of fruits and vegetables, wherein the divalent metal is at least one selected from the group consisting of copper, iron, nickel, manganese, tungsten, titanium, silver, and zinc, and the trivalent metal is at least one selected from the group consisting of aluminum, palladium, manganese, iron, and titanium . The present invention includes a freshness-preserving packaging material, the freshness-preserving packaging material comprising: fruits and vegetables; a metal material containing at least one of a divalent metal and a trivalent metal; and
The mass (g) of the metal material relative to the mass (g) of the fruit or vegetable is 0.00005 to 0.02000,
The fruits and vegetables and the metal material are packaged in the freshness-preserving packaging material,
the surface area (cm ² ) of the metal material relative to the volume (cm ³ ) of the packaging body is 0.5×10 ⁻⁴ to 15.0×10 ⁻³ ;
The divalent metal is at least one selected from the group consisting of copper, iron, nickel, manganese, tungsten, titanium, silver, and zinc, and the trivalent metal is at least one selected from the group consisting of aluminum, palladium, manganese, iron, and titanium . The present invention includes a freshness-preserving packaging material, the freshness-preserving packaging material comprising: fruits and vegetables; a metal material containing at least one of a divalent metal and a trivalent metal; and
the mass (g) of the metal material relative to the volume (cm ³ ) of the package is 0.1×10 ⁻⁴ to 10.0×10 ⁻⁴ ,
The fruits and vegetables and the metal material are packaged in the freshness-preserving packaging material,
the surface area (cm ² ) of the metal material relative to the volume (cm ³ ) of the packaging body is 0.5×10 ⁻⁴ to 15.0×10 ⁻³ ;
The divalent metal is at least one selected from the group consisting of copper, iron, nickel, manganese, tungsten, titanium, silver, and zinc, and the trivalent metal is at least one selected from the group consisting of aluminum, palladium, manganese, iron, and titanium . The present invention includes a freshness-preserving packaging material, the freshness-preserving packaging material comprising: fruits and vegetables; a metal material containing at least one of a divalent metal and a trivalent metal; and
The fruit or vegetable is a strawberry, a mango, or an avocado;
The fruits and vegetables and the metal material are packaged in the freshness-preserving packaging material,
the surface area (cm ² ) of the metal material relative to the volume (cm ³ ) of the packaging body is 0.5×10 ⁻⁴ to 15.0×10 ⁻³ ;
The divalent metal is at least one selected from the group consisting of copper, iron, nickel, manganese, tungsten, titanium, silver, and zinc, and the trivalent metal is at least one selected from the group consisting of aluminum, palladium, manganese, iron, and titanium . A metal material containing at least one of a divalent metal and a trivalent metal ,
The freshness-preserving metal component includes a metal layer made of the metal material on the outermost surface, and the surface area of the metal layer is 70% to 100% of the total surface area of the freshness-preserving metal component;
The divalent metal is at least one selected from the group consisting of copper, iron, nickel, manganese, tungsten, titanium, silver, and zinc, and the trivalent metal is at least one selected from the group consisting of aluminum, palladium, manganese, iron, and titanium. A metal layer made of the metal material and an adhesive layer provided on one side of the metal layer,
The freshness-preserving metal member according to claim 15 , which is a freshness-preserving display member for fruits and vegetables. 16. The freshness-preserving metal component according to claim 15 , which is a decorative component for fruits and vegetables.