JP6636980B2 - Package suitable for maintaining freshness of fruits and vegetables, and method for maintaining freshness of fruits and vegetables - Google Patents

Description

  The present invention relates to a package excellent in freshness preserving performance of fruits and vegetables including cabbage, and more specifically, to store fruits and vegetables including cabbage in a packaging container having a polymer film and having a specific oxygen concentration. It relates to a package.

By providing a gas permeable portion in the polymer film base material, a gas permeable film that allows gas such as oxygen, carbon dioxide, and water vapor to pass therethrough from the gas permeable portion is used in the food field to produce fruits and vegetables, particularly fresh vegetables such as cut vegetables. It is suitably used as a packaging material. When vegetables, fruits, and the like are packaged using such a gas-permeable film, for example, an oxygen concentration suitable for maintaining the freshness of the contents of vegetables and fruits, for example, an oxygen concentration of about 1 to 4% can be maintained. It is known that contents can be stored while maintaining freshness for a relatively long period of time.
For example, in Patent Document 1, in a package of fruits and vegetables comprising a polymer film in which fruits and vegetables are sealed, the package is composed of (A) a perforated polymer film and (B) a non-porous polymer film; (A), at least one of the film properties (B), the water vapor permeability measured at 25 ° C. and a relative humidity of 75% is 50 to 800 gm ⁻² d ^{−1 based} on the effective surface area of the package. There is described a package containing fruits and vegetables characterized in that the open area ratio of (A) is 3 × 10 ^{−6 to} 7 × 10 ⁻⁴ % with respect to the effective surface area of the package. Specifically, (A) a perforated polymer film made of stretched polypropylene having a thickness of 35 μm and having 95 holes with an average pore diameter of 95 μm, and having nine holes with an average pore diameter of 60 μm, etc. It is used.

Cabbage is one of the most widely distributed vegetables among fruits and vegetables, and the above-described package and storage method can be suitably applied. In particular, cut cabbage, which has been cut from cabbage, has been increasing in demand in recent years because it can be easily served for meals, and because cabbage is one of the most common vegetables for salads, etc., it has high economical efficiency. Have value. For this reason, packages and storage methods that are particularly suitable for maintaining the freshness of cut cabbage are being actively studied, and the oxygen transmission rate, carbon dioxide transmission rate, and water vapor transmission rate of the package, and the oxygen concentration in the package And setting the carbon dioxide concentration to specific values (for example, Patent Document 2).
However, even with the above technology, it may not be possible to sufficiently achieve both the suppression of the off-flavor of cabbage and the suppression of browning.Considering the suppression of the number of viable bacteria that affects the safety, preservability, and hygienic handling of food. Meanwhile, the solution was required.

JP-A-5-168400 JP 2004-242504 A

In view of the above-described limitations of the background art, the present invention provides a packaging in which fruits and vegetables including cabbage are stored in a packaging container from the viewpoint of the influence of the freshness given by the water content of cut vegetables (specifically, cut cabbage). The body is excellent in freshness maintaining function of the fruits and vegetables, which can suppress the browning of the fruits and vegetables including the cabbage, and at the same time, can extremely effectively suppress the generation of the odor, and can also suppress the increase in the number of viable bacteria. It is an object of the present invention to provide a packaged body.
In the present invention, in particular, in view of the actual situation of commercial transactions, with respect to a package in which fruits and vegetables including cabbage are stored in a packaging container, after packaging of the cabbage, a condition of 2 ° C. or more and 15 ° C. or less, preferably about 10 ° C. It is another object of the present invention to provide a package which can suppress the generation of off-flavor and browning which may affect the commercial value for a long time, and which is excellent in suppressing an increase in the number of viable bacteria.

  The present inventor has conducted intensive studies and, as a result of controlling the water content of cabbage at the time of storage to a specific amount, in a package containing vegetables and fruits including cabbage in a packaging container containing a polymer film, The present inventors have found that the above problems can be solved, and have completed the present invention.

That is, the present invention
[1]
A package comprising a vegetable or vegetable containing cabbage stored in a packaging container containing a polymer film, wherein the cabbage has a water content of less than 23% when stored.
[2]
The package according to [1], wherein the inside of the package is sealed with nitrogen.
[3]
[1] or [2], wherein the generation of the cabbage odor can be suppressed for 96 hours or more at 10 ° C. after packaging, and the generation of browning of the cabbage can be suppressed for 144 hours or more at 10 ° C. after packaging. A package according to item 1.
[4]
The method according to any one of [1] to [3], wherein the viable cell count of the cabbage is 168 hours or more at 10 ° C. after packaging, and can be suppressed more than the case where the water content of the cabbage is 23%. Packaging.
[5]
The package according to any of [1] to [4], wherein the polymer film has an oxygen permeability of 500 cc / m ² / day / atm or more and 30000 cc / day / atm at 20 ° C. and 90% RH. body.
[6]
The package according to any one of [1] to [5], wherein the packaging container does not have a through hole that can be confirmed with an ink leak checker.
[7]
The package according to any one of [1] to [6], wherein the thickness of the polymer film is 15 μm or more and 45 μm or less.
[8]
The package according to any one of [1] to [7], wherein the polymer film is a stretched polypropylene film, a polyethylene-based film, or a laminate of a stretched film and a polyethylene-based film.
[9]
The package according to any one of [1] to [8], wherein the polymer film contains at least one antibacterial agent or is coated with at least one antibacterial agent.
[10]
The package for maintaining freshness of fruits and vegetables according to any one of [1] to [9], further containing a moisture absorbent and / or an antibacterial agent.
[11]
A method for maintaining freshness of fruits and vegetables under a condition of 2 ° C. or more and 15 ° C. or less, comprising a step of storing fruits and vegetables including cabbage having a water content of less than 23% in a packaging container containing a polymer film.
[12]
The method for maintaining freshness of fruits and vegetables according to [11], further comprising a step of enclosing nitrogen in the packaging container.

According to the present invention, in a package containing vegetables and fruits including cabbage in a packaging container, by controlling the water content of the cabbage to be stored to a specific amount, for a long time from the time of encapsulation, its off-flavor, browning, Then, the number of viable bacteria can be effectively suppressed in total. Therefore, the package and the method for maintaining freshness of the fruits and vegetables including the cabbage according to the present invention can exert an effect that the freshness maintaining function of the fruits and vegetables is excellent.
According to the present invention, in particular, for a package containing vegetables and fruits including cabbage in a packaging container, after packaging the cabbage, 2 ° C or more and 15 ° C or less, preferably about 10 ° C for a long time, It can both suppress the generation of off-flavors and browning that affect the commercial value, and can also provide a package excellent in suppressing the increase in the number of viable bacteria, and has high commercial value in commercial transactions. The effect can be achieved.

Hereinafter, embodiments for implementing the present invention will be described.
The present invention is a package in which fruits and vegetables including cabbage are stored in a packaging container containing a polymer film, and the cabbage has a water content of less than 23% when stored. As described above, the package of the present invention has at least the packaging container and the fruits and vegetables stored therein.
The numerical range in the present application includes a lower limit and an upper limit unless otherwise specified. Therefore, for example, the notation “500 to 30000 cc / day / atm” means 500 cc / day / atm or more and 30000 cc / day / atm unless otherwise specified.

Packaging Container The packaging container constituting the package of the present invention contains a polymer film. Here, "comprising a polymer film" means that the entire packaging container is composed of a polymer film, and that a part of the packaging container such as a lid is composed of a polymer film. The purpose is to include both.
Therefore, the packaging container may be a flexible packaging container in which all or a main part is formed of a flexible polymer film, a so-called packaging bag, such as a flexible polymer film and coated paper. May be a flexible packaging container in which other flexible members are combined, or a packaging container in which a flexible polymer film and a rigid member are combined, for example, as a lid material. It may be a combination of a molecular film and a rigid member such as a tray or a cup.

In an embodiment in which the packaging container is a so-called packaging bag, for example, three or two sides are heat-sealed in a state where two polymer films are overlapped with each other or one polymer film is folded. To form a packaging bag. The remaining one side can be sealed by arranging the contents such as fruits and vegetables in the packaging bag and then similarly fusing by heat sealing.
The shape of such a packaging bag in a plan view may be a circle, a triangle, a rectangle, or a polygon having a rectangle or more, but it is preferable to form a rectangle from the viewpoint of workability and ease of handling.

  The packaging container used in the present invention comprises the above-described polymer film, and its oxygen permeability is not particularly limited, and the amount, type, and after a predetermined time after packaging of the fruits and vegetables to be stored are not limited. An appropriate oxygen permeability can be selected according to a desired internal oxygen concentration. Usually, at 20 ° C. and 90% RH, those having a range of 500 to 30,000 cc / day / atm can be preferably used.

Fruits and Vegetables The package of the present invention contains fruits and vegetables including cabbage in the packaging container. Here, the expression "the vegetable or vegetable includes" the cabbage "is intended to include both the case where the whole of the vegetable is composed of cabbage and the case where a part of the vegetable is composed of cabbage. Therefore, the fruits and vegetables stored in the packaging container may or may not include other vegetables and fruits. Furthermore, as long as cabbage is included, it may contain components other than fruits and vegetables, for example, foods other than fruits and vegetables, seasonings, food additives, and the like.
The cabbage constituting the package of the present invention (stored in the packaging container) is preferably a cabbage that has been cut, washed, dehydrated or dried to have an appropriate water content.

The “cabbage” that constitutes the package of the present invention (contained in a packaging container) is a concept that includes general head vegetables belonging to the Brassicaceae Brassica genus, and is limited to vegetables distributed under the name “cabbage” itself. Not done.
That is, the “cabbage” referred to here is, as a preferable example, a cold cabbage (winter) cabbage, a spring cabbage, a plateau cabbage, a red cabbage, a green ball (round ball), a savoy cabbage (crepe cabbage), a brussels sprouts, a petite veil, There are (but not limited to) bamboo shoot type cabbage such as Misaki Kanai and Tongari cabbage, and the concept encompasses all of these.

The cabbage (contained in the packaging container) constituting the package of the present invention has a water content of less than 23% when stored. The water content is preferably 7% or more and less than 23%, and more preferably 9% or more and 22% or less from the viewpoint of simultaneously suppressing the off-flavor and browning of cabbage and suppressing the number of viable bacteria over a long period of time. More preferably, it is 9% or more and 21% or less, still more preferably 9% or more and 15% or less, and particularly preferably 9% or more and 12% or less.
In commercial transactions, the texture of cabbage may be regarded as important. However, when the water content of the cabbage is reduced, the texture of fresh cabbage may be reduced even when the cabbage is excellent in suppression of off-flavor and browning. In the case where while maintaining the texture as a fresh cabbage and simultaneously suppressing the off-flavor and browning of the cabbage and suppressing the number of viable bacteria, the water content is 12% as a whole. It is preferably not less than 20% and not more than 15%, more preferably not less than 15% and not more than 19%. The water content in this range is excellent in that it can effectively suppress the odor, browning and viable cell count of the cabbage while maintaining the fresh texture of the cabbage for a long time.
In addition, the water content in the present application is based on the “analysis method for nutrition labeling in nutrition labeling standards” (Consumer Affairs Agency), and the sample dried under reduced pressure at 70 ° C. for 5 hours is defined as zero (starting point). Say from the weight minutes. For example, when 100 g of cut cabbage is reduced to 90 g by drying under reduced pressure at 70 ° C. for 5 hours, the water content is 10 g / 100 g = 10%.

  The control of the water content of the cabbage at the time of storage is performed by a drying process using a drainer, but is not limited to this process as long as the purpose can be achieved. As the dehydration or drying treatment by draining, for example, a method by centrifugation, shaking, wind, absorption by a hygroscopic agent (drying agent), or a method by a combination of two or more of these can be mentioned, provided that the object can be achieved. However, the present invention is not limited to these methods.

The form of the cabbage (contained in the packaging container) constituting the package of the present invention is not particularly limited. It may be a freshly harvested one, a so-called pre-treated one from which outer leaves have been removed, or a cut form called a cut cabbage.
The form of the cabbage may be processed by cutting or other processing such as slicing, and is not limited to a processing method within the scope of the present invention. Therefore, specifically, it also includes forms such as chopped and shredded.
The cabbage constituting the package of the present invention (contained in a packaging container) may be one that has been subjected to any or all of treatments such as washing, cooling, and dehydration within the scope of the present invention. Alternatively, none of these processes may be performed.

In the present invention, when cabbage is stored in the packaging container, there is no particular limitation on other fruits and vegetables that can be stored together, and non-heated or heated fruits and vegetables that can be served together with the cabbage can be appropriately stored. Specific examples of such fruits and vegetables include fruits such as banana, mango, plum, apple, strawberry, orange, grape, Japanese pear, pear, root vegetables such as carrot, yam, burdock, tomato, cucumber, Fruits and vegetables such as eggplant, pepper, edamame, okra, mushrooms such as mung bean sprouts, soy bean sprouts, syrup, shiitake mushrooms, shimeji mushrooms, eryngii, maitake, fungi mushrooms such as matsutake mushrooms, broccoli, spinach , Komatsuna, bok choy, radish, lettuce, asparagus, but not limited thereto.
When cabbage is stored, the mode of controlling and maintaining the oxygen concentration, which is one mode of the present embodiment, is particularly effective in maintaining the freshness of a fruit or vegetable that is substantially breathing due to its action.

In the present invention, the form of other fruits and vegetables that can be stored together with the cabbage in the packaging container is not particularly limited. Therefore, the fruits and vegetables including cabbage may be as-harvested, so-called pre-processed vegetables from which outer leaves and the like have been removed, and so-called cut vegetables (cut cabbage). It may be. The fruits and vegetables may have been subjected to any or all of the processing such as washing, cooling, and dehydration, or may be those without any of these processings.
In addition, in the case of the cabbage in which the stored and freshness-retained cabbage is cut, it is preferable that the cabbage be cut, washed, dehydrated, or dried to adjust the water content to an appropriate value. Specifically, the cut cabbage is washed with hypochlorous acid at 80 to 120 ppm for 10 to 20 minutes based on the “Manual for Mass Cooking Facilities Hygiene Management” (Ministry of Health and Welfare), and then “analysis method for nutrition labeling based on nutrition labeling standards” ( The amount of water measured based on weight loss when dried under reduced pressure at 70 ° C. for 5 hours based on the Consumer Affairs Agency) is used to determine the balance between prevention of odor generation and prevention of appearance deterioration such as browning, and the number of viable bacteria. From the viewpoint of suppression of, the content is set to a range of 23% or less and preferably 7% or more and less than 23%, more preferably 9% or more and 22% or less, and more preferably 9% or more and 21% or less. It is still more preferably 9% or more and 15% or less, and particularly preferably 9% or more and 12% or less. Further, considering the balance including the maintenance of the texture of the cabbage, the water content is preferably 12% or more and 20% or less, more preferably 15% or more and 19% or less.

The demand for cut vegetables has been increasing in recent years because they can be easily served for meals, etc., and their commercial value is high, and thus they have high economic value. Cut cabbage is a typical example of cut vegetables, and a mixture of these as it is can be easily served as a salad or the like to a meal, and therefore has a particularly high economic value. On the other hand, cabbage generally tends to sharply activate its respiratory action and metabolic reaction when cut, resulting in a sharp decline in quality. For this reason, cut cabbage is liable to have an unpleasant odor, browning, and an increase in the number of viable bacteria, which have a large effect on the commercial value, as time passes. Above all, off-flavors are said to be particularly strong as compared to other common vegetables, and have a significant effect on commercial value. However, in the present embodiment, the off-flavor can also be effectively suppressed, so that it can be effectively used for keeping the freshness of cut cabbage together with the suppression of browning and viable cell count.
The number of viable bacteria usually means the number of viable mesophilic aerobic bacteria that grow under certain conditions, and is the most representative index indicating the degree of microbial contamination of food. It is used for comprehensive evaluation of food safety, preservability, and hygiene handling. Generally, the number of colonies observed after culturing at 35 ° C. ± 1.0 ° C. for 48 hours ± 3 hours under aerobic conditions using a standard agar medium was calculated. Be told.

  The preferred oxygen concentration for maintaining freshness differs depending on the type and form of the cabbage (contained in the packaging container) constituting the package of the present invention, and accordingly, within the scope of the present invention, the oxygen permeability and the like. The mode of the polymer film giving a high oxygen permeability can be appropriately selected. By setting these appropriately, it is possible to maintain effective freshness of any of the above-mentioned cabbage and fruits and vegetables that are stored together when present, within the scope of the present invention.

Package The internal oxygen concentration of the package of the present invention is not particularly limited as long as the object of the present invention can be achieved, but is usually maintained at an oxygen concentration of more than 0% by volume to about 0.5% by volume or less. It is desired to do so.
The temperature condition at which the package of the present invention is placed is not particularly limited as long as the object of the present invention can be achieved, but is preferably 2 ° C. or more and 15 ° C. or less, more preferably 10 ° C. in view of the actual conditions of commercial transactions. .
The oxygen concentration inside the package can be specified, for example, by measuring the oxygen concentration with an O ₂ / CO ₂ analyzer for food packaging Check Material 3 manufactured by Dansensor.
Here, "after packaging" refers to the elapsed time since the packaging container was sealed after storing the fruits and vegetables including cabbage in the packaging container. For example, "3 days after packaging" refers to the packaging container. Means that three days have passed since the cabbage was stored in the container, and then the packaging container was sealed (ie, after 72 hours).

  From the viewpoint of realizing the desired internal oxygen concentration described above, it is preferable that the inside of the packaging container is sealed with nitrogen. This is because, by sealing and saturating with nitrogen when the packaging container is sealed, the internal oxygen concentration immediately after packaging can be eliminated. In addition, since the pressure inside the packaging container can be kept high by further enclosing nitrogen, the inflow of outside air having a higher oxygen concentration is prevented, and the internal oxygen concentration is maintained at 0.5% by volume or less for a long time after packaging. Can be kept low.

Polymer Film In order to realize the above-mentioned desired internal oxygen concentration, it is desirable to configure a packaging container using a polymer film having an oxygen permeability of a predetermined value or more.
That is, the lower limit of the oxygen permeability of the polymer film used in the present invention is preferably 500 cc / m ² / day / atm or more at 20 ° C. and 90% RH, and more preferably 800 cc / m ² / day / atm or more. Is more preferable, it is more preferably 1000 cc / m ² / day / atm or more, and further preferably 5000 cc / m ² / day / atm or more. When the oxygen permeability at 20 ° C. and 90% RH is 1000 cc / m ² / day / atm or more, oxygen from outside air is introduced, and the desired internal oxygen concentration can be maintained. Specifically, the internal oxygen concentration in the packaging container saturated with nitrogen at the time of encapsulation can be maintained at an internal oxygen concentration of more than 0% by volume for at least 6 days (144 hours) after packaging. The upper limit of the oxygen permeability of the polymer film used in the present invention is not particularly limited, but is preferably 30,000 cc / m ² / day / atm or less at 20 ° C. and 90% RH, and is preferably 15,000 cc / m ^2. / more preferably day / atm or less, more preferably less ^{10000cc / m 2 / day / atm} , more preferably not more than ^{5000cc / m 2 / day / atm} , 3000cc / m 2 / day / Atm or less is more preferable.

The oxygen permeability of the polymer film used in the present invention can be measured, for example, by the following method.
First, a bag having an inner size of 220 mm × 240 mm is formed by the following method.
One film is folded almost evenly into two pieces, about 5 mm wide, and heat sealing is performed by setting the scale of the heating condition to 3 with an impulse sealer (manufactured by Fuji Impulse Co., Ltd., product number Fi-200-10WK). One of the sides substantially perpendicular to the heat-sealed side is heat-sealed so that the side is almost at the center, and the whole of the other side is heat-sealed except for an end portion of about 2 cm, which is one of the communicating parts, and has an inner dimension of 220 mm × Form a 240 mm bag.
Next, nitrogen gas is injected from the communicating portion, and when the inside of the bag becomes saturated, almost all the gas in the bag is discharged from the communicating portion. After repeating this operation 5 times, nitrogen gas is injected to saturate the inside of the bag with nitrogen gas, and the communicating portion is heat-sealed with the impulse sealer under the same conditions. The bag saturated with nitrogen gas is left for 6 hours in a room at 22 ° C. and a relative humidity of 40% in the air (1 atm, oxygen concentration: 21%, nitrogen concentration: 79%).
The oxygen concentration inside the bag is specified, for example, by measuring the oxygen concentration with an O ₂ / CO ₂ analyzer for food packaging Check Material 3 manufactured by Dansensor. Further, the volume of the gas in the bag is measured, and the oxygen permeability is calculated from the following equation.
(Formula) Oxygen permeability = internal oxygen concentration change (%) / 100 × volume (cm ³ ) × 24 × 60 / hour (360 minutes) × 10000 cm ² / area (1232 cm ² ) /0.21 (partial pressure of oxygen) )

By appropriately selecting the material, thickness, processing method, and the like of the polymer film, the oxygen permeability of the polymer film can be appropriately adjusted.
For example, the oxygen permeability of a 30 μm OPP (biaxially oriented polypropylene) bag is 1000 cc / m ² / day / atm, but it becomes 2000 cc / m ² / day / atm when one 100φ hole is opened. In consideration of mechanical strength and the like, the thickness of the polymer film is more preferably 15 to 45 μm, and particularly preferably 20 to 40 μm.

As described above, the oxygen permeability of the polymer film can be adjusted by appropriately selecting the material, thickness, processing method, and the like of the polymer film. It is not necessary to provide an opening in the polymer film. In particular, the oxygen permeability of 1000 cc / m ² / day / atm or more at 20 ° C. and 90% RH in a preferred embodiment of the present invention can be achieved without providing an opening in the polymer film.
Since it is not necessary to provide an opening in the polymer film, the manufacturing process becomes simpler and lower in cost, and it is not necessary to precisely control the size, shape, and the like of the opening.
The absence of an opening in the polymer film can be confirmed, for example, by the fact that the polymer film forming the packaging container does not have a through hole that can be confirmed by an ink leakage checker.

On the other hand, in one embodiment of the present invention, in order to achieve a desired oxygen permeability, for example, when it is necessary to use a thick polymer film or a polymer material having a low oxygen permeability, May be used together. The shape of the opening is not particularly limited, and may be circular, substantially circular, or slit-like. A circular or substantially circular opening is preferable in that processing is easy, and the like, and a slit-shaped opening is preferable in that foreign substances can be effectively prevented from entering.
The size of each opening and the number of openings can be appropriately set and changed as long as the oxygen permeability of the polymer film is appropriate, and in that case, the opening occupying the effective area of the polymer film The number is a guide. For example, it is a slit-shaped opening having a length of 2 mm, and in a closed state, the width as a through hole cannot be visually recognized by an optical microscope (manufactured by Olympus, model SZH-131) at a magnification of 4 ×. In the case where a package is provided, there is an effect of increasing the oxygen permeability of about 1000 cc / m ² / day / atm every time one package is present in a 200 mm × 200 mm package. It is preferable to determine the number of slit openings from the oxygen permeability of the whole container.

  There is no particular limitation on the thickness of the polymer film used in the present invention. Suitable oxygen permeability, flexibility when forming a packaging container, strength, transparency, economy, etc. From the viewpoints of accuracy and easiness in forming the portion, a suitable thickness may be appropriately selected in relation to the material for forming the polymer film. Typically, the thickness of the polymer film is preferably from 10 to 45 μm, more preferably from 20 to 40 μm, still more preferably from 15 to 35 μm, and particularly preferably from 18 to 32 μm. .

  The material of the polymer film is not particularly limited, but a polymer used for a conventional film for packaging fruits and vegetables can be appropriately used. For example, polyethylene, polypropylene, polyethylene terephthalate, polystyrene, nylon (polyamide), ethylene vinyl acetate copolymer (EVA), polybutylene succinate, polybutylene succinate adipate, polylactic acid and the like can be mentioned. Also, for example, a natural polymer such as cellophane can be used. Further, any one of these materials may be used alone, or a plurality of these materials may be blended and / or laminated.

  From the viewpoint of easiness of processing and cost, the material of the polymer film is preferably a thermoplastic resin. Examples of the thermoplastic resin include homopolymers or copolymers of α-olefins such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene. Specifically, ethylene polymers such as high-pressure low-density polyethylene, linear low-density polyethylene (LLDPE), and high-density polyethylene, propylene homopolymer, propylene / α-olefin random copolymer, and propylene block copolymer And polyolefins such as poly 1-butene and poly 4-methyl / 1-pentene. Examples of the thermoplastic resin include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon-6, nylon-66, and polymethaxylene adipamide; polyvinyl chloride; polyimide; Biodegradable resins such as vinyl copolymers or saponified products thereof, polyvinyl alcohol, polyacrylonitrile, polycarbonate, polystyrene, ionomer, polylactic acid, polybutylene succinate, and mixtures thereof. One of these thermoplastic resins may be used, or two or more of them may be used in combination. Among these, as the thermoplastic resin, polyolefin, polyester, polyamide and the like are preferable because of their excellent rigidity and transparency. Further, as the thermoplastic resin, an ethylene-based polymer and a propylene-based polymer are more preferred because of their light weight and excellent film processability, and a propylene-based polymer is further preferred from the viewpoint of flexibility and transparency.

<Propylene polymer>
As the propylene-based polymer, propylene homopolymer (also referred to as homo PP) manufactured and sold under the name of polypropylene, propylene / α-olefin random copolymer (also referred to as random PP) And a crystalline polymer containing propylene as a main component, such as a mixture of a propylene homopolymer and a low-crystalline or amorphous propylene-ethylene random copolymer (also called a block PP). . The propylene-based polymer may be a mixture of propylene homopolymers having different molecular weights, and a propylene homopolymer and a random copolymer of propylene and ethylene or an α-olefin having 4 to 10 carbon atoms. It may be a mixture.

  As the propylene-based polymer, specifically, polypropylene, propylene / ethylene copolymer, propylene / ethylene / 1-butene copolymer, propylene / 1-butene copolymer, propylene / 1-pentene copolymer Propylene as a main monomer, such as propylene / 1-hexene copolymer or propylene / 1-octene copolymer, and copolymerized with at least one or more selected from ethylene and α-olefins having 4 to 10 carbon atoms. Coalescence. These may be used alone or in combination of two or more.

The density of the propylene-based polymer is preferably 0.890 to 0.930 g / cm ³ , more preferably 0.900 to 0.920 g / cm ³ . The MFR (ASTM D1238, load 2160 g, temperature 230 ° C.) of the propylene polymer is preferably 0.5 to 60 g / 10 min, more preferably 0.5 to 10 g / 10 min, and 1 to 5 g / 10 min. Is more preferred.

<Ethylene polymer>
As the ethylene polymer, a homopolymer of ethylene, ethylene as a main monomer, a copolymer thereof with at least one kind of α-olefin having 3 to 8 carbon atoms, an ethylene / vinyl acetate copolymer, Saponified products and ionomers. Specifically, polyethylene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-pentene copolymer, ethylene / 1-hexene copolymer, ethylene / 4-methyl-1-pentene Copolymers and copolymers of ethylene as a main monomer and at least one or more α-olefins having 3 to 8 carbon atoms, such as an ethylene / 1-octene copolymer, may be mentioned. The proportion of α-olefin in these copolymers is preferably from 1 to 15 mol%.

  Examples of the ethylene-based polymer include ethylene polymers manufactured and sold under the name of polyethylene. Specifically, high-pressure low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE) are preferred, and LLDPE is more preferred. LLDPE is a copolymer of ethylene and a small amount of propylene, butene-1, heptene-1, hexene-1, octene-1, 4-methyl-pentene-1, and the like. Further, the ethylene polymer may be a homopolymer of ethylene or a polymer mainly composed of ethylene such as LLDPE.

Density of the ethylene polymer is preferably ^{0.910~0.940g / cm 3, 0.920~0.930g / cm} 3 is more preferable. When the density is 0.910 g / cm ³ or more, heat sealability is improved. When the density is 0.940 g / cm ³ or less, workability and transparency are improved.

  The blend and / or laminate may be a blend of any of the above polymers and / or a laminate, and may be any of the above polymers and a material other than the polymer. And / or a laminate. That is, the polymer film is made of a material other than a polymer, such as a heat stabilizer (antioxidant), a weather stabilizer, an ultraviolet absorber, a lubricant, a slip agent, a nucleating agent, an antiblocking agent, an antistatic agent and an antifogging agent. And various fillers such as talc, silica, and diatomaceous earth, in addition to pigments and dyes, or a laminate of a polymer film and metal foil, paper, nonwoven fabric, or the like.

In the present invention, the polymer film constituting the packaging container may be any of a non-stretched film and a stretched film.
From the viewpoint of mechanical strength and the like, stretched films of various polymers can be suitably used.
In particular, a stretched film (stretched polypropylene film) using a propylene-based polymer is excellent in mechanical strength, transparency, heat resistance and the like, and therefore can be particularly preferably used in the packaging container used in the present invention.
In addition, a film using an ethylene-based polymer (polyethylene-based film) may be either a non-stretched film or a stretched film, but from the viewpoint of heat sealing properties and the like, a non-stretched film is particularly preferably used. be able to.
Examples of particularly preferable polymer films constituting the packaging container in the present invention include a stretched polypropylene film, a polyethylene-based film, and a laminate of a stretched film and a polyethylene-based film.

<Stretched polypropylene film>
The stretched polypropylene film preferably used in the present invention may be composed of a film stretched in at least one direction, or the stretched polypropylene film itself may be stretched in at least one direction. When a biaxially stretched film is obtained as the stretched polypropylene film, it can be easily produced by, for example, sequentially or simultaneously biaxially stretching it. When a biaxially stretched film is obtained as a stretched polypropylene film, it is usually stretched 5 to 8 times in the machine direction, and then 8 to 10 times in the transverse direction by using a tenter mechanism, and the film thickness is finally adjusted. It can be manufactured by a method in which the thickness is 20 to 40 μm, or the film is stretched in the longitudinal and transverse directions by 5 to 10 times (25 to 100 times in area ratio), respectively.
<Polyethylene film>
The polyethylene-based film preferably used in the present invention is a film containing the ethylene-based polymer. Although various known molding methods can be used for the polyethylene-based film, cast molding by extrusion with an extruder is preferable from the viewpoint of production efficiency.

<Stretched film>
Polyamide film made of nylon 6, nylon 66, etc., film made of polyester represented by polyethylene terephthalate, polyethylene naphthalate, polycarbonate film, ethylene-vinyl alcohol copolymer film, polyvinyl alcohol film, polyvinyl chloride film, polyvinylidene chloride It is a uniaxially or biaxially stretched film made of a film, a polystyrene film, a polyolefin such as polypropylene, poly-L-lactic acid, poly-D-lactic acid, or a stereocomplex polylactic acid in which poly-L-lactic acid and poly-D-lactic acid are precisely coordinated.

<Laminated body of stretched film and polyethylene film>
The laminate of a stretched film and a polyethylene-based film preferably used in the present invention is obtained by laminating the above-mentioned polyethylene-based film layer and the stretched film layer. The polyethylene film may be stretched in one or two directions, but is preferably a non-stretched film from the viewpoint of the stability of the mechanical strength of the packaging bag.
Dry lamination is performed to attach a stretched film and a polyethylene-based film that have been prepared in advance using an adhesive, but it is necessary to perform a corona treatment on the stretched film surface where the adhesive is applied from the viewpoint of adhesion stability. preferable. Specifically, the surface tension of the film surface after corona treatment is preferably 35 mN / m or more, more preferably 40 mN / m or more, from the viewpoint of adhesion stability.

Further, these polymer films may be subjected to a stretching process, an anti-fogging process or printing, and may be an inorganic antibacterial agent such as silver or copper, or an organic antibacterial agent such as chitin, chitosan or allyl isothiocyanate. Agents may be applied, or they may be kneaded in a film.
From the viewpoint of maintaining the freshness of contents such as fruits and vegetables, it is preferable that the polymer film contains at least one antibacterial agent.
Further, a specific surfactant may be present on the surface of the polymer film in a specific amount, or the polymer film may have a specific amount of a specific surfactant to have an antibacterial function. For example, palmityl diethanolamine, stearyl diethanolamine, at least one compound selected from the group consisting of glycerin monolaurate and diglycerin monolaurate is preferably present on at least one surface of the polymer film, It is particularly preferred that one compound is present at 0.002 to 0.5 g / m ² . Alternatively, it is preferable that the polymer film contains at least one compound selected from the group consisting of palmityl diethanolamine, stearyl diethanolamine, glycerin monolaurate and glycerin monocaprate, and 0.001 to 3 parts by mass. It is particularly preferred that it be contained.
When a specific amount of a specific surfactant is present on the surface of the polymer film, or when the polymer film contains a specific amount of the specific surfactant, dew condensation on the surface of the polymer film is suppressed, and various bacteria Is suppressed, the growth of various bacteria in dew (drip) is suppressed, and an antibacterial function is exhibited.

From the viewpoint of transparency, flexibility, cost, and the like, it is particularly preferable to use a stretched polypropylene film, which has been widely used in the related art, or a laminate of a stretched polypropylene film and a polyethylene-based film as a polymer film. . Since these films are generally excellent in heat sealability, productivity is good in the production of packaging containers.
When using a stretched propylene film alone, the thickness is preferably 10 to 100 μm, and when using a laminate of a stretched polypropylene film and a polyethylene film, the former thickness is 10 to 50 μm, and the latter is Preferably, the thickness is from 10 to 120 μm.

  When a polymer film that is not always suitable for heat sealing is used, the polymer film may be formed by laminating or coating a sealant layer on all or a part of the polymer film. For example, a cellophane film coated with an acrylic resin, a film in which linear low-density polyethylene (LLDPE) polystyrene and EVA are laminated on polyethylene terephthalate (PET), and the like, can be used as a suitable polymer film.

The present invention provides a method for producing a package, and a method for maintaining freshness. According to the present invention, a vegetable or vegetable containing cabbage is stored in a packaging container including a polymer film, and the amount of water contained in the cabbage at the time of storage is appropriately adjusted. Can be manufactured, and the method for maintaining freshness of fruits and vegetables, which is one embodiment of the present invention, can be performed.
Hereinafter, the method for producing a package of the present invention will be described by taking a package of fresh cabbage for keeping freshness as an example.

  First, in the pretreatment step, the cabbage from which the outer leaves have been removed manually, divided into two to four parts, and the core has been removed is supplied to the conveyor. The cabbage conveyed by the conveyor is cut by a slicer, washed in a washing tank filled with cold water while also cooling, and then drained by a centrifugal dehydrator, dry air, etc. so that the water content becomes less than 23%. . The dehydrated cut cabbage is packed in a packaging container (one side not sealed) containing the polymer film used in the present embodiment, and after weighing, the packaging container is sealed to maintain the freshness of the cut cabbage. A package is manufactured.

  The cut cabbage dehydrated in the above pretreatment step is weighed so as to have a predetermined amount, and packed into a packaging container (one side not sealed) containing the polymer film used in the present embodiment, The packaging container is sealed, and a package for keeping freshness in which cut cabbage is stored (packaged) is manufactured.

From the viewpoint of maintaining the freshness of the cut cabbage, it is preferable to use a sharp blade and reduce the number of scratches on the cut surface.
In addition, as the cut width is smaller, the cut area increases, and it becomes more difficult to maintain freshness. Therefore, from the viewpoint of maintaining freshness, it is preferable that the cut width is wide as long as it conforms to the form of demand.
Furthermore, if a lot of germs adhere to the cut cabbage from the beginning, it becomes more difficult to maintain the freshness. Therefore, it is preferable to reduce the adhesion of germs as much as possible by washing well. Washing is particularly effective for maintaining freshness, since it not only reduces the adhesion of various bacteria, but also has the effect of removing cell fluids and the like that contain highly active enzymes and the like and may cause discoloration.
In addition, it is important to sufficiently remove moisture attached to the surface of the cut cabbage after washing to maintain freshness. In cut cabbage, the moisture content needs to be reduced to less than 23%. Of particular importance. Even if water is drained after standing still after washing, much water still adheres to the surface of the cut cabbage, so use a centrifugal dehydrator etc. to sufficiently remove water and dry with dry air. It is effective to do. This is because it is possible to suppress the growth of various germs due to extra small water droplets. More specifically, based on the "Manual for Mass Cooking Facilities Sanitation Management" (Ministry of Health and Welfare), after washing with hypochlorous acid at 80 to 120 ppm for 10 to 20 minutes, "Analysis method of nutrition labeling in nutrition labeling standards" (Consumer Affairs Agency) The amount of water measured based on the weight loss when dried under reduced pressure at 70 ° C. for 5 hours is less than 23%, from the viewpoint of suppressing odor and preventing appearance deterioration such as browning.

The package for maintaining freshness of fruits and vegetables according to the present embodiment is used for storing fruits and vegetables including cabbage (preferably cabbage adjusted to an appropriate moisture content by cutting, washing, dehydrating or drying) and sealing the packaging container. Later, nitrogen filling and / or degassing may be performed. By performing nitrogen filling and / or degassing, it becomes possible to quickly reach a desired oxygen concentration designed as an equilibrium state between the oxygen permeability of the packaging container and the respiratory volume of the fruits and vegetables, which is advantageous for maintaining freshness. .
Degassing may be performed after the packaging container is sealed from the viewpoints of efficiency improvement, space saving, and elimination of a specific gas during the distribution process.

  According to the method as described above, for example, after carrying out a step of storing fruits and vegetables including cut cabbage having a water content of less than 23% in a packaging container containing a polymer film, the oxygen concentration in the packaging container is measured. Thereafter, the freshness of the fruits and vegetables including cut cabbage can be effectively maintained by maintaining the content at more than 0% by volume to 0.5% by volume or less under the condition of 10 ° C. for at least 6 days (144 hours).

In the package of the present invention, only fruits and vegetables including cabbage may be stored in the packaging container, or other members may be stored.
For example, in addition to the fruits and vegetables, a moisture absorbent and / or an antibacterial agent may be contained in the packaging container.
There is no particular limitation on the hygroscopic agent, and known or commercially available materials having a hygroscopic effect or a humidity controlling effect can be used. Examples of those preferably used as a moisture absorbent include, for example, activated carbon, silica gel, alumina gel, silica alumina gel, anhydrous magnesium sulfate, zeolite, synthetic zeolite, calcium oxide, calcium chloride, and calcined alum, or a mixture thereof. But not limited thereto.
Among them, it is particularly preferable to use activated carbon which has relatively little effect on fruits and vegetables and concerns about use near foods such as fruits and vegetables. Activated carbon can be in any form of powder or granules, and the raw material can be coconut shell, sawdust, charcoal, bamboo charcoal, lignite, peat, stone, oil pitch, or anything else. The activated carbon is desirably packaged for each unit of use with a nonwoven fabric, cellophane, paper, or the like, but the activated carbon itself may be fibrous. The activated carbon packaging material is preferably a heat-sealing material such as a nonwoven fabric made of a synthetic resin, but any paper or natural fiber may be used as long as it has water vapor permeability and does not spill activated carbon. no problem.

  There is no particular limitation on the antibacterial agent, and a substance having an antibacterial action can be used as appropriate. It can be preferably used. More specifically, chitosan, allyl isothiocyanate, hinokitiol, limonene, and the like, which are natural antibacterial agents, can be stored in a packaging container.

  Hereinafter, the present invention will be specifically described with reference to Examples / Comparative Examples. The present invention is not limited in any sense by the following examples.

In the following Examples / Comparative Examples, each characteristic was evaluated by the following methods.
(With or without opening)
After injecting a red penetration liquid (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: Ageless Seal Check Spray) into the packaging container, set the heating condition scale to 3 with an impulse sealer, heat seal with a width of about 5 mm, (Kokuyo PPC paper, paper A4) was pressed, and the presence or absence of the opening was confirmed by the presence or absence of transfer of the ink to the paper.
(amount of water)
As described above, the amount of water in the cabbage stored in the packaging container was dried at 70 ° C. for 5 hours under reduced pressure based on “Analysis of Nutrition Labeling in Nutrition Labeling Standards” (Consumer Affairs Agency). The sample was taken as zero (starting point) to determine the weight from there. For example, when 100 g of cut cabbage is reduced to 90 g by drying under reduced pressure at 70 ° C. for 5 hours, the water content is 10 g / 100 g = 10%.
(Oxygen concentration and carbon dioxide concentration)
The measurement was performed using an O ₂ / CO ₂ analyzer for food packaging Check Material 3 manufactured by Dansensor.
(appearance)
The package was opened, the cabbage taken out was arranged, and the area of the entire browning portion was visually evaluated with n (the number of samples) = 5 centering on the cut cross section.
The evaluation criteria are as follows.
A: There is no problem in a fresh state B: There is some browning but it can be said that it is fresh C: There is browning but it is in the same state as on the market, and it can be sold D: The browning is more intense and the consumer cares E: A state in which browning is further strong and cannot be sold In the present application, in the case of evaluation of C, D, and E, browning was evaluated to occur, and in the case of D and E, browning that lost commercial value occurred was evaluated. did.
(smell)
When the seal of the package was opened, the face was approached and the odor inside was smelled, and the sensory evaluation was performed with n (number of samples) = 5.
The evaluation criteria are as follows.
A: There is no problem in a fresh state B: Slightly smell but fresh state C: Smell strong but in the same state as in the market and available for sale D: Smell more strong and the consumer cares E: A state in which the smell is further strong and cannot be sold In the present application, in the case of evaluation of C, D, and E, it is evaluated that an unusual odor has occurred, and in the case of D and E, it is evaluated that an unusual odor that loses commercial value has occurred did.
(Viable cell count)
The number of viable bacteria was determined using a standard agar medium under aerobic conditions for n (number of samples) = 5 on the 4th day (96 hours after) and the 7th day (168 hours after) after packaging of cut cabbage. The number (unit: CFU / g) at which colonies were observed after culturing at 35 ° C. ± 1.0 ° C. for 48 hours ± 3 hours was calculated.

(Example 1)
Two OPP (biaxially oriented polypropylene) films each having a thickness of 30 μm are overlapped, three sides are sealed with heat sealing, and then cut. One side is an unsealed packaging bag (170 mm × 235 mm; (Area: 799 cm ² ).
When the presence or absence of an opening in the film was confirmed, it was confirmed that there was no opening.
Regarding gas permeability of the film, the oxygen permeability was 1000 cc / m ² / day / atm at 20 ° C. and 90% RH.
The oxygen concentration was maintained at a low concentration of 2% by volume or less during the measurement period.
The cut cabbage used in this example was produced as follows.
After removing cabbage stains and damaged parts, the cabbage was cut into a width of about 2 mm, and washed with hypochlorous acid at 100 ppm for 10 minutes based on the "Manual for Mass Cooking Facilities Sanitation Management" (Ministry of Health and Welfare). Thereafter, dehydration and drying were properly performed to produce cut cabbage.
In addition, as described above, the cut cabbage water content is measured based on the weight loss when dried under reduced pressure at 70 ° C. for 5 hours based on “Analysis Method of Nutrition Labeling in Nutrition Labeling Standards” (Consumer Affairs Agency). did. As a result, the water content was 9% as shown in Table 1.
50 g of cut cabbage having a water content shown in Table 1 was stored in a packaging container, and the inside of the container was completely filled with nitrogen and heat-sealed to prepare a package. The package was stored at 10 ° C., and the internal oxygen concentration and carbon dioxide concentration were measured every day for 6 days at 10 ° C. from the package of the cut cabbage to evaluate the smell and appearance of the cut cabbage. Table 1 shows the results.
In addition, the viable cell count (unit: CFU / g) on days 4 and 7 from the cut cabbage packaging was examined.

(Examples 2-3)
In accordance with the “Manual for Mass Cooking Facilities Hygiene” (Ministry of Health and Welfare), after passing through the steps of 1 cut, 2 washings and washing with water, 3 dehydration steps are replaced with “analysis method for nutrition labeling based on nutrition labeling standards” (consumption The dewatering condition and drying conditions were adjusted using a dehydrator and a dryer with the sample dried under reduced pressure at 70 ° C. for 5 hours as zero (starting point) based on the Example 2) and 15% (Example 3) of the cut cabbage were obtained, and the production and evaluation of the package were performed in the same manner as in Example 1. Table 1 shows the results.

(Comparative Example 1)
In accordance with the “Manual for Mass Cooking Facilities Hygiene” (Ministry of Health and Welfare), after passing through the steps of 1 cut, 2 washings and washing with water, 3 dehydration steps are replaced with “analysis method for nutrition labeling based on nutrition labeling standards” (consumption The sample which was dried under reduced pressure at 70 ° C. for 5 hours based on the above-mentioned method was set to zero (starting point), and the dehydrating conditions and the drying conditions were adjusted using a dehydrator and a dryer. A cut cabbage was obtained, and a package was prepared and evaluated in the same manner as in Example 1. Table 1 shows the results.

In Examples 1 to 3 in which the cut cabbage had a moisture content of less than 23% when stored in a packaging container, the odor was evaluated by A or B even on the fourth day (after 96 hours) from the packaging. Although it can be said that the fresh state is maintained, even on the fifth day (after 120 hours) from the packaging, an unpleasant odor is generated. confirmed.
In Examples 1 to 3, it was also confirmed that the fresh state was maintained by the A or B evaluation even on the sixth day (after 144 hours) from the packaging with respect to the appearance (browning).
On the other hand, in Comparative Example 1 in which the cut cabbage had a moisture content of 23% when stored in a packaging container, although the evaluation was C, an unpleasant odor was generated on the third day after packaging (72 hours later). On the fourth day (after 96 hours), it was confirmed that an unpleasant odor was noticed by the D-rated consumers and the commercial value was lost.
Regarding the appearance (browning) of Comparative Example 1, even on the sixth day (144 hours) after packaging, it was confirmed by A or B evaluation that the fresh state was maintained as in the example.
For this reason, when the cut cabbage has a moisture content of 23% when stored in a packaging container as in Comparative Example 1, a odor is generated on the third day (72 hours after the packaging), and the product Although it does not lose its value, it cannot be said that odor and suppression of browning have both been achieved, and on the fourth day (96 hours after packaging), it gives off unpleasant odors that consumers are worried about. On the other hand, in Examples 1 to 3 in which the amount of water is lower than this water content while generating and losing commercial value, the fresh state is maintained while suppressing the generation of odor and browning even on the fourth day (after 96 hours) from the packaging. It was also found that even on the fifth day (after 120 hours) from the packaging, the generation of both offensive odor and browning that consumers who lose commercial value are concerned can be suppressed.

Furthermore, using Examples 1 to 3 and Comparative Example 1, the viable cell count was measured on the fourth day (after 96 hours) and the seventh day (after 168 hours) from the packaging of the cut cabbage. Note that, in this case, the package was stored at 10 ° C. until the 7th day (after 168 hours). Table 1 also shows the results.
From this result, in Comparative Example 1 in which the water content of cut cabbage was 23%, the water content was less than 23% on both the fourth day (after 96 hours) and the seventh day (after 168 hours). It was confirmed that the viable cell count was higher than that of any of the examples described in (1). Therefore, Examples 1 to 3 in which the water content of the cut cabbage is within the range of less than 23% are also superior to Comparative Example 1 in which the water content is 23% in terms of suppressing the number of viable bacteria. all right. In addition, when the water content was 20%, it was examined in the same manner, but it was 2.8 × 10 ⁶ CFU / g on the fourth day and 3.7 × 10 ⁶ CFU / g on the seventh day. It was also confirmed that the viable cell count was suppressed as compared with 23% of Comparative Example 1.

  According to the present invention, cabbage to be packaged in a package containing fruits and vegetables including cabbage having high economic value (particularly cabbage adjusted to an appropriate moisture content by cutting, washing, dehydrating or drying). By controlling the moisture concentration in the food to an appropriate value, the fresh odor of the cabbage is maintained while effectively suppressing the unpleasant odor and browning of the fruits and vegetables, the number of viable bacteria, and the texture as needed. As a result, it has practically high commercial value, and has high applicability in various industrial fields such as food processing, distribution, and restaurant.

Claims (10)

Fruits and vegetables including cabbage are stored in a packaging container obtained by fusing two polymer films in a state of being overlapped with each other or in a state of folding one polymer film. According to the Ministry of Health, Labor and Welfare's "Manual for Mass Cooking Facilities Hygiene Management", after washing with hypochlorous acid at 80 to 120 ppm for 10 to 20 minutes, the Consumer Affairs Agency "analysis method for nutrition labeling in nutrition labeling standards" at 70 ° C. A package having a water content of 9 % or more and 15% or less measured based on weight loss when dried under reduced pressure for 5 hours .   The package according to claim 1, wherein the inside of the package is sealed with nitrogen. 3. The package according to claim 1, wherein the polymer film has an oxygen permeability of 500 cc / m ² / day / atm or more and 3000 cc / m ² / day / atm at 20 ° C. and 90% RH. 4.   The package according to any one of claims 1 to 3, wherein the packaging container does not have a through hole that can be confirmed with an ink leak checker.   The package according to any one of claims 1 to 4, wherein the thickness of the polymer film is 15 µm or more and 45 µm or less.   The package according to any one of claims 1 to 5, wherein the polymer film is a stretched polypropylene film, a polyethylene-based film, or a laminate of a stretched film and a polyethylene-based film.   The package according to any one of claims 1 to 6, wherein the polymer film contains at least one antibacterial agent or has at least one antibacterial agent applied thereto.   The package for keeping freshness of fruits and vegetables according to any one of claims 1 to 7, further comprising a moisture absorbent and / or an antibacterial agent. Based on the Ministry of Health, Labor and Welfare's "Manual for Mass Cooking Facilities Hygiene" in a packaging container in which two polymer films are superimposed on each other or fused together with one polymer film folded, After washing with hypochlorous acid at 120 ppm for 10 to 20 minutes, measured based on the weight loss when dried under reduced pressure at 70 ° C. for 5 hours based on the Consumer Affairs Agency “Analysis method for nutrition labeling in nutrition labeling standards” A method for maintaining the freshness of fruits and vegetables under conditions of 2 ° C or more and 15 ° C or less, comprising a step of storing fruits and vegetables including cabbage having a water content of 9 % or more and 15% or less.   The method for maintaining freshness of fruits and vegetables according to claim 9, further comprising a step of enclosing nitrogen in the packaging container.