JP6577506B2 - Package suitable for keeping freshness of fruits and vegetables, and method for keeping freshness of fruits and vegetables - Google Patents

Description

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

A gas permeable film that is provided with a gas permeable portion on a polymer film substrate and allows gas such as oxygen, carbon dioxide, and water vapor to pass through the gas permeable portion is used in the field of foods, particularly for fresh vegetables such as fruits and vegetables. It is suitably used as a packaging material. Using such a gas permeable film, for example, when packaging vegetables, fruits, etc., the oxygen concentration suitable for maintaining the freshness of the vegetables, fruits, etc., for example, an oxygen concentration of about 1 to 4% is maintained. It is known that contents can be stored while maintaining freshness over a relatively long period of time.
For example, in Patent Document 1, in a package containing fruits and vegetables made of a polymer film in which fruits and vegetables are sealed, the package is composed of (A) a porous polymer film and (B) a non-porous polymer film, The water vapor transmission rate measured under the conditions where the film characteristics of at least one of (A) and (B) are 25 ° C. and the relative humidity is 75% is 50 to 800 gm ⁻² d ^{−1 based} on the effective surface area of the package. There is described a packaged product with 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 porous polymer film made of stretched polypropylene having a thickness of 35 μm, having 95 holes with an average pore diameter of 30 μm, 9 holes with an average pore diameter of 60 μm, etc. in use.

Among fruits and vegetables, cabbage is one of the most widely distributed vegetables, and the packaging body and the storage method as described above can be suitably applied. In particular, cut cabbage cut from cabbage has increased in demand in recent years because it can be easily used for meals, and since cabbage is one of the most common vegetables for salads, it is highly economical. Have value. For this reason, a packaging body particularly suitable for maintaining the freshness of cut cabbage and a storage method have been actively studied. The oxygen transmission rate, carbon dioxide transmission rate, and water vapor transmission rate of the packaging body, and the oxygen concentration in the packaging body. It has been proposed to set the carbon dioxide concentration to a specific value (see, for example, Patent Document 2).
However, the demand level of consumers and consumers for the quality of cabbage including cut cabbage is improving year by year, especially the demand level regarding the suppression of odor, and further the compatibility of suppression of odor and discoloration, Even with the above prior art, it has reached a level that is difficult to solve.
Against such a background, there is a strong demand for a technology that can maintain the freshness of fruits and vegetables including cabbage beyond the level of the prior art, such as suppressing odor generation very effectively and simultaneously suppressing browning over a long period of time. It was.

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

In view of the limitations of the background art described above, the present invention is a packaging body that contains fruits and vegetables containing cabbage in a packaging container, and at the same time extremely effective in generating odor while suppressing browning of the fruits and vegetables containing cabbage. It is an object of the present invention to provide a package excellent in the function of maintaining freshness of fruits and vegetables.
As a result of intensive studies, the inventor of the present invention is particularly effective in maintaining the freshness such as suppression of the smell of fruits and vegetables including cabbage, by controlling the internal oxygen concentration of the package after a predetermined time has elapsed after packaging. As a result, the present invention has been completed.

That is, the present invention
[1]
The fruit and vegetables containing cabbage are stored in a packaging container containing a polymer film, and the internal oxygen concentration at 72 hours after sealing of the package is 1.2 vol% or more and 18.0 vol% or less, Packaging body.

Hereinafter, [2] to [10] are each one aspect or preferred embodiment of the present invention.
[2]
The package according to [1], wherein browning of the cabbage and generation of odor are suppressed for 72 hours or more under a condition of 10 ° C. after sealing of the package.
[3]
The package according to [1] or [2], wherein an oxygen concentration in the packaging container immediately after sealing the package is 0% by volume or more and 25.0% by volume or less.
[4]
The oxygen permeability of the polymer film is 3000 cc / m ² / atm / day / atm or more and 50000 cc / m ² / atm / day or less at 20 ° C. and 90% RH, from [1] to [3] The package according to any one of the above.
[5]
The package according to any one of [1] to [4], wherein the polymer film has a thickness of 15 to 45 μm.
[6]
The package according to any one of [1] to [5], wherein the polymer film is a stretched polypropylene film, a polyethylene film, or a laminate of a stretched film and a polyethylene film.
[7]
The package according to any one of [1] to [6], wherein the polymer film contains at least one antibacterial agent or is coated with at least one antibacterial agent.
[8]
The package according to any one of [1] to [7], wherein the cabbage is a cut cabbage.
[9]
The package according to any one of [1] to [8], further containing a hygroscopic agent and / or an antibacterial agent.
[10]
Oxygen concentration after holding for 72 hours under conditions of 2 ° C. to 15 ° C. after sealing the package in the packaging container, and storing the fruits and vegetables containing cabbage in the packaging container comprising the polymer film The method for maintaining the freshness of fruits and vegetables, comprising the step of:

  According to the present invention, by controlling the oxygen concentration inside the package after a predetermined time from the packaging to a predetermined range, the occurrence of odor is suppressed extremely effectively while suppressing the browning of fruits and vegetables containing cabbage, Provided are a package that can effectively suppress the freshness of fruits and vegetables, and a method for maintaining the freshness of fruits and vegetables.

Hereinafter, modes for carrying out the present invention will be described.
The present invention contains fruits and vegetables containing cabbage in a packaging container containing a polymer film, and the internal oxygen concentration at 72 hours after sealing of the package is 1.2 vol% or more and 18.0 vol% or less. It is a package. That is, the package of the present invention has at least a packaging container and fruits and vegetables stored therein.

Packaging container The packaging container which comprises the package of this invention comprises a polymer film. Here, “comprising a polymer film” means that when the entire packaging container is made of a polymer film and when a part of the packaging container such as a lid is made of a polymer film, It is intended to include both.
Therefore, the packaging container may be a flexible packaging container, or a so-called packaging bag, whose whole or main part is composed of a flexible polymer film, such as a flexible polymer film and coated paper. It 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 in the form of a combination of a molecular film and a rigid member such as a tray or 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. A packaging bag can be formed by, for example, fusing. The remaining one side can be sealed by arranging the contents such as fruits and vegetables in the packaging bag and then fusing it by heat sealing.
Such a packaging bag may have a circular shape, a triangular shape, a quadrangular shape, or a polygonal shape equal to or more than a quadrangular shape in a plan view, but is preferably rectangular from the viewpoint of processability 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. For example, it is 800 cc / m ² / day / atm or more and 50000 cc / m ² / day. / atm can be preferably used those which are within the range, more preferably 900cc ^/ m 2 ^/ day ^/ atm or more, the use of what is within the scope of the following 35000cc ^/ m 2 ^/ day ^/ atm It is possible to select an appropriate oxygen permeability in accordance with the amount and type of fruits and vegetables to be stored and a desired internal oxygen concentration 72 hours after sealing the package.

Vegetables and Fruits The package of the present invention contains fruits and vegetables containing cabbage in the packaging container. Here, the phrase “contains” cabbage includes the case where all the fruits and vegetables are made of cabbage and the case where some of the fruits and vegetables are made of cabbage. Therefore, the fruits and vegetables stored in the packaging container may or may not contain vegetables, fruits and the like other than cabbage. Furthermore, as long as cabbage is included, ingredients other than fruits and vegetables, for example, foods other than fruits and vegetables, seasonings, food additives and the like may be included.

The “cabbage” constituting the package of the present invention (contained in the packaging container) is a concept including general headed vegetables belonging to the Brassicaceae genus Brassica, and is limited to vegetables distributed under the name of “cabbage” itself. Not.
That is, “cabbage” here is, as a preferable example, cold ball (winter) cabbage, spring cabbage, plateau cabbage, red cabbage, green ball (round ball), savoy cabbage (chirimen cabbage), Brussels sprouts, petit veil, This concept encompasses all of Misaki Kanai / Tongari Kyabetsu, but is not limited thereto.

  In the present invention, there are no particular limitations on the fruits and vegetables other than cabbage that can be stored with cabbage in the packaging container, and unheated or heated fruits and vegetables that can be used for food together with cabbage can be appropriately stored. Specific examples of such fruits and vegetables include fruits such as bananas, mangoes, ume, apples, strawberries, mandarin, grapes, Japanese pears, pears, radish, carrots, Chinese yam, root vegetables such as burdock, tomatoes, Fruits and vegetables such as cucumber, eggplant, bell pepper, green beans, okra, sprouts such as mung bean sprout, soybean sprout, cypress, fungi (mushrooms) such as shiitake, shimeji, eringi, maitake, matsutake, broccoli , Spinach, komatsuna, chinensai, lettuce, leafy vegetables such as asparagus, flower buds or seedlings, but are not limited thereto. The action of the present embodiment of controlling and maintaining the oxygen concentration is particularly effective for maintaining the freshness of fruits and vegetables that are substantially breathing.

In the present invention, there is no particular limitation on the form of the fruit and vegetables containing cabbage stored in the packaging container and kept fresh. Therefore, the fruit and vegetables containing cabbage may remain as harvested, and the outer leaves and the like are removed. It may be a so-called pre-processed one, or a so-called cut vegetable (cut cabbage) that has been cut. In addition, the fruits and vegetables may be those that have been subjected to any or all of the treatments such as washing, cooling, and dehydration, and may be those that do not perform any of these treatments. In addition, when the cabbage that is stored and kept fresh is cut cabbage, it is preferable to perform cutting, washing, dehydration and / or drying to adjust the moisture content to an appropriate level. More specifically, for example, after cutting cabbage into 80 to 120 ppm for 10 to 20 minutes of hypochlorous acid based on the “Manufacturing Sanitation Management Manual” (Ministry of Health and Welfare) Method ”(Consumer Agency) Based on the weight loss when dried under reduced pressure at 70 ° C. for 5 hours, the moisture content measured based on the range of 10 to 20% is to prevent odor generation and browning, etc. It is particularly preferable from the viewpoint of the balance of prevention of appearance deterioration.

  The demand for cut vegetables has increased in recent years because it can be easily used for meals, and has high economic value. Cut cabbage is representative of cut vegetables and has a particularly high economic value because it can be simply used as a salad for meals. On the other hand, vegetables, especially cabbage, are cut and respiratory action and metabolic reaction are rapidly activated, and the quality tends to be drastically lowered. Since this embodiment can be used effectively for maintaining the freshness of such a cut cabbage, it has a particularly high economic value.

  Depending on the type and form of the cabbage (and the fruits and vegetables stored with the cabbage, if present), which is preferably cut, washed, dehydrated or dried and adjusted to an appropriate moisture content, the preferred oxygen concentration for maintaining freshness is However, the oxygen permeability varies to some extent within the scope of the present invention, and the mode of the polymer film that gives such oxygen permeability is also different. By appropriately setting these, the cabbage (and exists) In any case, the freshness of any fruits and vegetables stored with the cabbage can be effectively maintained by the present invention.

Packaging The internal oxygen concentration of the packaging body of the present invention after being held for 72 hours under the condition of 10 ° C. after sealing the packaging body is 1.2 volume% or more and 18.0 volume% or less.
Occurrence of cabbage odor in the fruits and vegetables contained in the packaging container when the internal oxygen concentration after holding for 72 hours under the condition of 10 ° C. after sealing the package is 1.2% by volume or more. It can be suppressed very effectively. The internal oxygen concentration after holding for 72 hours under the condition of 10 ° C. after sealing of the package is 18.0% by volume or less, thereby effectively reducing the browning of cabbage in the fruits and vegetables contained in the packaging container. Can be suppressed. In a preferred embodiment of the package of the present invention, the browning of cabbage in fruits and vegetables and the generation of odor are suppressed for a long period of time after sealing of the package, preferably over 72 hours under conditions of 10 ° C. Can do.
The internal oxygen concentration after holding the package of the present invention for 72 hours under the condition of 10 ° C. after sealing the package is more preferably 2.0% by volume or more, and 2.5% by volume or more. More preferably, it is more preferably 3.0% by volume or more.
The internal oxygen concentration after holding the package of the present invention for 72 hours under the condition of 10 ° C. after sealing the package is more preferably 17.5% by volume or less, and 17.0% by volume or less. Is particularly preferred.

The oxygen concentration inside the package can be specified by, for example, sampling the gas inside the package with a sampling needle tube and measuring the oxygen concentration with a zirconia oxygen concentration meter for food packaging.
Here, “after sealing the package” means the elapsed time after the packaging container is sealed after storing the fruits and vegetables containing cabbage in the packaging container. "After holding for 72 hours under the conditions of" refers to the state immediately after holding the fruits and vegetables containing cabbage in the packaging container and then holding the packaging container for 72 hours under the condition of 10 ° C. Say.

In the package of the present invention, oxygen is consumed when the fruits and vegetables containing the cabbage stored therein breathe, so the internal oxygen concentration often decreases with time. Therefore, in the present invention in which the internal oxygen concentration after holding for 72 hours under the condition of 10 ° C. after sealing of the package is 1.2% by volume or more, under the condition of 10 ° C. after sealing of the package. Therefore, it is highly possible that the internal oxygen concentration is 1.2% by volume or more over 0 to 72 hours. Such a history of oxygen concentration is particularly preferable for further effectively suppressing the occurrence of cabbage odor in fruits and vegetables.
Regarding the history of oxygen concentration, the oxygen concentration in the packaging container immediately after sealing the package, that is, immediately after sealing the packaging container after storing the fruits and vegetables containing cabbage in the packaging container is 0 to 25.0. It is preferable that it is volume%. For example, the generation of odor from cabbage or the like can be particularly effectively suppressed by storing a gas containing oxygen in a predetermined amount or more together with fruits and vegetables containing cabbage in a packaging container and sealing the packaging container.
From the viewpoint of effectively suppressing the generation of odor from cabbage or the like, when the oxygen concentration in the packaging container immediately after packaging is 10% or less, the oxygen permeability of the packaging container is 3000 cc / m ² / atm / It is preferably not less than day, and more preferably not less than 4500 cc / m ² / atm / day.
The oxygen concentration in the packaging container immediately after packaging is more preferably 5 to 22.0% by volume, more preferably 10 to 22.0% by volume, and 15 to 22.0% by volume. More preferably, it is 18-22.0 volume% especially preferable.

In addition, in order to realize the above-described desired internal oxygen concentration, it is desirable to configure the packaging container using a polymer film having an oxygen permeability of a predetermined value or less.
That is, the oxygen permeability of the polymer film used in the present invention is 50000 cc / m ² / atm / day or less at 20 ° C. and 90% RH from the viewpoint of preventing cabbage browning and mold generation. preferable. Even when the oxygen permeability at 20 ° C. and 90% RH is not more than the above value, oxygen can be prevented from entering from the outside air, and after holding the package at 10 ° C. for 72 hours, A moderate internal oxygen concentration of 0.0% by volume or less can be maintained, and the browning of fruits and vegetables can be effectively suppressed. Oxygen permeability of the polymer film used in the present invention, 20 ° C., in 90% RH, more preferably less ^{45000cc / m 2 / atm / day} , not more than 35000cc ^/ m 2 ^/ atm ^/ day More preferred is 32000 cc / m ² / atm / day or less.
There is no particular lower limit to the oxygen permeability of the polymer film, but 800 cc / m ² / atm / day at 20 ° C. and 90% RH as long as a normal polymer film without gas barrier coating or the like is used. Generally, this is the case.
Moreover, from the viewpoint of preventing the generation of odor from the stored fruits and vegetables, the polymer film preferably has an oxygen permeability that allows the fruits and vegetables to breathe. From this viewpoint, the oxygen permeability of the polymer film is preferably 1000 cc / m ² / atm / day or more at 20 ° C. and 90% RH, and preferably 3000 cc / m ² / atm / day or more. It is particularly preferably 4500 cc / m ² / atm / day or more.

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 a (cm) × b (cm) is formed by the following method.
One film is folded almost equally into two, approximately 5 mm wide, and heat sealing is performed with an impulse sealer (manufactured by Fuji Impulse Co., product number Fi-200-10WK) with the heating condition scale set to 3, and the heat sealing is performed. Heat seal the whole of one side that is almost perpendicular to the heat seal side so that the side is almost in the middle, except the end of about 2 cm that is one communicating part of the other side, and the inner dimension a ( cm) × b (cm).
Next, nitrogen gas is injected from the communication portion, and when the inside of the bag becomes saturated, almost all the gas in the bag is discharged from the communication portion. After repeating this operation five 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 in a room at 22 ° C. and 40% relative humidity in air (1 atm, oxygen concentration: 21%, nitrogen concentration: 79%) for 6 hours.
Next, about 20 cc is sampled with a sampling needle tube, and the oxygen concentration in the bag is measured with a food packaging zirconia oxygen concentration meter (model number LC-750F, manufactured by Toray Engineering Co., Ltd.). Furthermore, the volume of the gas in the bag is measured, and the oxygen permeability is calculated from the following formula.
(Expression) Oxygen permeability = change in internal oxygen concentration (%) / 100 × volume (cm ³ ) × 24 × 60 / hour (360 minutes) × 10000 cm ² / area (a × b × 2 cm ² ) /0.21 ( Oxygen partial pressure)

By appropriately selecting the material, thickness, processing method and the like of the polymer film, the oxygen permeability of the polymer film can be adjusted as appropriate. For example, in the case of a biaxially stretched polypropylene (OPP) film, by setting the thickness to 15 μm or more, the oxygen permeability at 20 ° C. and 90% RH can be reduced to 50000 cc / m ² / day or less, which is preferable. . In consideration of mechanical strength, workability, etc., the thickness of the polymer film is more preferably 15 to 45 μm, and particularly preferably 18 to 42 μm.

As described above, the oxygen permeability of the polymer film can be adjusted by appropriately selecting the material, thickness, processing method, etc. of the polymer film. It is not necessary to provide an opening in the polymer film. In particular, the oxygen permeability of 50000 cc / m ² / day or less at 20 ° C. and 90% RH in a preferred embodiment of the present invention can be realized without providing an opening in the polymer film.
Since it is not necessary to provide an opening in the polymer film, the manufacturing process is simpler and less expensive, and it is not necessary to precisely control the size, shape, etc. of the opening.
The absence of an opening in the polymer film can be confirmed, for example, by the fact that the polymer film constituting the packaging container does not have a through-hole that can be confirmed with an ink leak checker.

On the other hand, in one embodiment of the present invention, when it is necessary to use a thick polymer film or a polymer material having a low oxygen permeability, the desired oxygen permeability for maintaining the respiration of fruits and vegetables is obtained. In order to realize, an opening provided in the polymer film may be used in combination. The shape of the opening is not particularly limited, and may be circular, substantially circular, or may be slit. A circular or substantially circular opening is preferable because it is easy to process, and a slit-shaped opening is preferable because it can effectively prevent foreign substances 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. In that case, the openings occupying the effective area of the polymer film The number of For example, a slit-like opening having a length of 2 mm, and in the closed state, the width as a through-hole cannot be visually recognized with an optical microscope (Olympus, model SZH-131) at a magnification of 4 times. When a product is provided, there is an effect of increasing the oxygen permeability of about 1000 cc / m ² / day / atm for every 200 mm × 200 mm packaging container. Packaging required based on such knowledge It is preferable to determine the number of slit openings from the oxygen permeability of the entire container.

  There is no particular limitation on the thickness of the polymer film used in the present invention, and when an opening is provided such as suitable oxygen permeability, flexibility when forming a packaging container, strength, transparency, economy, etc. From the viewpoint of accuracy and ease in forming the part, a suitable thickness may be selected as appropriate in relation to the material forming the polymer film. Typically, the thickness of the polymer film is preferably 15 to 45 μm, more preferably 18 to 42 μm.

  Although there is no restriction | limiting in particular in the material of the said polymer film, The polymer used for the film for conventional fruit and vegetables packaging can be used suitably. Examples thereof include polyethylene, polypropylene, polyethylene terephthalate, polystyrene, nylon (polyamide), ethylene vinyl acetate copolymer (EVA), polybutylene succinate, polybutylene succinate adipate, and polylactic acid. Further, for example, natural polymers 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 ease of processing and cost, the polymer film is preferably made of 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 method low density polyethylene, linear low density polyethylene (LLDPE), high density polyethylene, propylene homopolymer, propylene / α-olefin random copolymer, propylene block copolymer. And propylene-based polymers 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 polymetaxylene adipamide, polyvinyl chloride, polyimide, and ethylene / acetic acid. Examples thereof include a vinyl copolymer or a saponified product thereof, polyvinyl alcohol, polyacrylonitrile, polycarbonate, polystyrene, ionomer, polylactic acid, polybutylene succinate and the like, or a mixture thereof. These thermoplastic resins may be used alone or in combination of two or more. Among these, as the thermoplastic resin, polyolefin, polyester, polyamide and the like are preferable because they are excellent in rigidity and transparency. As the thermoplastic resin, an ethylene polymer and a propylene polymer are more preferable because they are lightweight and excellent in film processability, and a propylene polymer is more preferable from the viewpoint of flexibility and transparency.

<Propylene polymer>
Examples of the propylene polymer include a propylene homopolymer (also referred to as homo PP) manufactured and sold under the name of polypropylene, and a propylene / α-olefin random copolymer (also referred to as random PP). And crystalline polymers mainly composed of propylene such as a mixture of propylene homopolymer and low crystalline or amorphous propylene / ethylene random copolymer (also called block PP). . Further, the propylene-based polymer may be a mixture of propylene homopolymers having different molecular weights, and is composed of 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.

  Specific examples of the propylene polymer include polypropylene, propylene / ethylene copolymer, propylene / ethylene / 1-butene copolymer, propylene / 1-butene copolymer, and propylene / 1-pentene copolymer. Copolymer of propylene such as propylene / 1-hexene copolymer and propylene / 1-octene copolymer as a main monomer and at least one selected from ethylene and α-olefin having 4 to 10 carbon atoms Coalescence is mentioned. These may use 1 type and may use 2 or more types together.

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

<Ethylene polymer>
Examples of the ethylene polymer include a homopolymer of ethylene, a copolymer of ethylene as a main monomer and at least one α-olefin having 3 to 8 carbon atoms, an ethylene / vinyl acetate copolymer, Saponifications and ionomers are mentioned. Specifically, polyethylene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-pentene copolymer, ethylene / 1-hexene copolymer, ethylene / 4-methyl-1-pentene Examples thereof include copolymers of ethylene as a main monomer, such as a copolymer and an ethylene / 1-octene copolymer, and at least one kind of an α-olefin having 3 to 8 carbon atoms. The proportion of α-olefin in these copolymers is preferably 1 to 15 mol%.

  Examples of the ethylene polymer include ethylene polymers manufactured and sold under the name of polyethylene. Specifically, high pressure method low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE) are preferable, and LLDPE is more preferable. 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. The ethylene polymer may be an ethylene homopolymer 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. Further, 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 and / or laminate of any of the above polymers, and any of the above polymers and a material other than the polymer. Blends and / or laminates. That is, the polymer film is 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, an antifogging agent. In addition to pigments and dyes, various fillers such as talc, silica, and diatomaceous earth may be included, or a laminate of a polymer film and metal foil, paper, nonwoven fabric, or the like may be used.

In the present invention, the polymer film constituting the packaging container may be an unstretched film or 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.
Further, the film using the ethylene polymer (polyethylene film) may be either a non-stretched film or a stretched film, but a non-stretched film is particularly preferably used from the viewpoint of heat sealability and the like. be able to.
Examples of the polymer film that is particularly suitable as the polymer film constituting the packaging container in the present invention include a stretched polypropylene film, a polyethylene film, and a laminate of the stretched film and the polyethylene 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. Moreover, when obtaining a biaxially stretched film as a stretched polypropylene film, it can also be easily manufactured by, for example, sequential or simultaneous biaxial stretching. 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 stretched 8 to 10 times in the transverse direction using a tenter mechanism, and the film thickness is finally adjusted. Or 20 to 40 μm, or by stretching 5 to 10 times (25 to 100 times in terms of surface magnification) in the longitudinal direction and the transverse direction, respectively.
<Polyethylene film>
The polyethylene film preferably used in the present invention is a film containing the ethylene polymer. Various known molding methods can be used for the polyethylene film, but cast molding by extrusion using an extruder is preferred 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 Films, polystyrene films, polyolefins such as polypropylene, and poly-L lactic acid, poly-D lactic acid, or uniaxial or biaxially stretched films composed of stereocomplex crystal polylactic acid in which poly-L lactic acid and poly-D lactic acid are coordinated precisely.

<Laminated body of stretched film and polyethylene film>
A laminate of a stretched film and a polyethylene film preferably used in the present invention is obtained by laminating the polyethylene film layer and the stretched film layer. The polyethylene film may be stretched in one or two directions, but is preferably an unstretched film from the viewpoint of the stability of the mechanical strength of the packaging bag.
Dry lamination is performed by adhering a stretched film and a polyethylene film prepared in advance with an adhesive. From the viewpoint of adhesion stability, the surface of the stretched film to which the adhesive is applied should be corona treated. preferable. Specifically, the surface tension of the film surface after the corona treatment is preferably 35 mN / m or more, more preferably 40 mN / m or more, from the viewpoint of adhesion stability.

These polymer films may be stretched, antifogged or printed, and include inorganic antibacterial agents such as silver and copper, and organic antibacterial agents such as chitin, chitosan, and allylisothiocyanate. The agent may be applied, or these may be kneaded in the film.
From the viewpoint of maintaining the freshness of contents such as fruits and vegetables, the polymer film preferably contains at least one antibacterial agent.
Further, a specific amount of a specific surfactant is present on the surface of the polymer film, or the polymer film may have a specific amount of a specific surfactant to have an antibacterial function. For example, it is preferable that at least one compound selected from the group consisting of palmityl diethanolamine, stearyl diethanolamine, glycerol monolaurate and diglycerol monolaurate is present on at least one surface of the polymer film, it is particularly preferred that one compound 0.002~0.5g / ^{m 2} is present. Alternatively, the polymer film preferably contains at least one compound selected from the group consisting of palmityl diethanolamine, stearyl diethanolamine, glycerol monolaurate, and glycerol monocaprate, 0.001 to 3 parts by mass It is particularly preferable to contain.
When a specific amount of a specific surfactant is present on the surface of the polymer film, or the polymer film contains a specific amount of a specific surfactant, dew condensation on the surface of the polymer film is suppressed, Suppression of the growth of bacteria suppresses the growth of germs in the dew (drip) and exhibits an antibacterial function.

From the viewpoints of transparency, flexibility, cost, etc., it is particularly preferable to use a stretched polypropylene film or a laminate of a stretched polypropylene film and a polyethylene film that has been widely used in the art as a polymer film. . Since these films are generally excellent in heat sealability, productivity is good in the production of packaging containers.
In this case, when the stretched propylene film is used alone, the thickness is preferably 10 to 100 μm, and when the laminate of the stretched polypropylene film and the polyethylene film is used, the former thickness is 10 to 50 μm. The latter thickness is preferably 10 to 120 μm.

  When a polymer film that is not necessarily suitable for heat sealing is used, it may be formed by laminating or coating a sealant layer on all or part of the polymer film. Examples thereof include a cellophane film coated with an acrylic resin and a film obtained by laminating polyethylene terephthalate (PET) with linear low density polyethylene (LLDPE) polystyrene and EVA, and these can be used as suitable polymer films.

Method for producing package and method for maintaining freshness By storing fruits and vegetables containing cabbage in the packaging container of the present invention and adjusting the internal oxygen concentration as appropriate, the package of the present invention can be produced. The method for maintaining the freshness of fruits and vegetables, which is an embodiment of the present invention, can be implemented.
Hereinafter, the manufacturing method of the package of the present invention will be described by taking a package for maintaining the freshness of cut cabbage as an example.

  First, in the pretreatment step, the cabbage is removed manually, removed into 2 to 4 parts, and the core is removed, and the cabbage is supplied to the conveyor. The cabbage transported by the conveyor is cut by a slicer, washed in a washing tank filled with cold water as cooling, and then drained by a centrifugal dehydrator after draining. The dehydrated cut cabbage is packed in a packaging container (not sealed on one side) containing the polymer film used in this embodiment, and after packaging, the packaging container is sealed to maintain the freshness of the cut cabbage. A package is produced.

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 narrower, the cutting area increases and it becomes more difficult to maintain freshness. From the viewpoint of maintaining freshness, it is preferable that the cut width is wider as long as it matches the form of demand.
Furthermore, since it is more difficult to maintain freshness when a lot of germs are attached to the cut cabbage from the beginning, it is preferable to reduce the adhesion of germs as much as possible by washing the cut cabbage well. Washing is particularly effective for maintaining freshness because 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 can cause discoloration.
In addition, it is important for maintaining the freshness to sufficiently remove moisture adhering to the surface of the cut cabbage after washing. Even if the water is drained by standing after washing, it is often effective to remove water using a centrifugal dehydrator or the like because much water is still attached to the surface of the cut cabbage.
This is because by making the water appropriate, the growth of germs in the extra small water droplets can be suppressed. More specifically, for example, based on the “Manufacturing Sanitation Management Manual for Large-scale Cooking Facilities” (Ministry of Health and Welfare), after 80-120 ppm for 10-20 minutes of hypochlorous acid cleaning, “Analytical Methods for Nutrition Labeling in Nutrition Labeling Standards” (consumers From the viewpoint of suppressing the odor and preventing the deterioration of the appearance such as browning, the water content measured based on the weight loss when drying under reduced pressure at 70 ° C. for 5 hours based on the Agency) Particularly preferred.

In addition, the packaging body for fruit and vegetable freshness maintenance of this embodiment may perform nitrogen enclosure and / or deaeration after storage of the fruit and vegetables containing cabbage and sealing of a packaging container. By performing nitrogen sealing 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 respiration rate of fruits and vegetables, which is advantageous for maintaining freshness. .
In addition, deaeration may be performed after sealing the packaging container from the viewpoint of improving efficiency in the process of distribution, saving space, and eliminating a specific gas.

  After carrying out the step of storing the fruits and vegetables containing cabbage in the packaging container comprising the polymer film according to the method as described above, after sealing the package in the packaging container, the condition of 2 ° C. to 15 ° C. The freshness of the fruits and vegetables including cabbage can be effectively maintained by carrying out the step of setting the oxygen concentration to 1.2% or more and 18.0% by volume or less after holding for 72 hours.

The package of the present invention may contain only fruits and vegetables including cabbage in the packaging container, or may contain other members.
For example, in addition to fruits and vegetables, a hygroscopic agent and / or an antibacterial agent may be stored in the packaging container.
There is no limitation in particular in a moisture absorbent, The well-known or commercially available material which has a moisture absorption effect or a humidity control effect can be used. Suitable examples of the hygroscopic agent include 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. For example, but not limited to.
Among these, it is particularly preferable to use activated carbon which has relatively little concern about the influence on fruits and vegetables and the use of fruits and vegetables near foods. The activated carbon can be either powdered or granular, and the raw material can be anything from coconut husk, sawdust, charcoal, bamboo charcoal, lignite, peat, diamond, and petroleum pitch. The activated carbon is preferably wrapped in non-woven fabric, cellophane, paper, etc. for each unit used, but the activated carbon itself may be in the form of a fiber. The activated carbon packaging material is preferably a heat-sealable material such as a non-woven fabric made of a synthetic resin. However, any material such as paper or natural fiber can 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, but there is relatively little concern about the effects on fruits and vegetables including cabbage and use in the vicinity of fruits and vegetables that are foods. Antibacterial agents can be preferably used. More specifically, natural antibacterial agents such as chitosan, allyl isothiocyanate, hinokitiol, and limonene can be stored in the packaging container.

  Hereinafter, the present invention will be specifically described with reference to Examples / Comparative Examples. It should be noted that the present invention is not limited in any way by the following examples.

In the following examples / comparative examples, each characteristic was evaluated by the following method.
(Aperture)
After injecting the red penetrant (Mitsubishi Gas Chemical Co., Ltd., trade name: Ageless Seal Check Spray) into the packaging container, set the scale of the heating condition to 3 with an impulse sealer, heat seal with a width of about 5 mm, and paper (Kokuyo PPC paper, common paper A4) was pressed and the presence / absence and number of openings were confirmed based on the presence / absence of ink transfer to the paper. About what the opening part was seen, the magnitude | size and shape of the opening part were also observed with the optical microscope.
(Oxygen permeability)
First, a bag having an inner size of 220 mm × 240 mm was formed by the following method.
One film is folded almost equally into two, approximately 5 mm wide, and heat sealing is performed with an impulse sealer (manufactured by Fuji Impulse Co., product number Fi-200-10WK) with the heating condition scale set to 3, and the heat sealing is performed. Heat seal the whole of one side that is almost perpendicular to the heat seal side so that the side is almost in the center, except the end of about 2 cm that is one communicating part of the other side, and the inner dimension is 220 mm × A 240 mm bag was formed.
Next, nitrogen gas was injected from the communication portion, and after the bag was saturated, almost all the gas in the bag was discharged from the communication portion. After repeating this operation five times, nitrogen gas was injected to saturate the inside of the bag with nitrogen gas, and the communicating portion was heat sealed with the impulse sealer under the same conditions. The bag saturated with nitrogen gas was left in a room at 22 ° C. and 40% relative humidity in air (1 atm, oxygen concentration: 21%, nitrogen concentration: 79%) for 6 hours.
Next, about 20 cc of the gas in the bag was sampled with a sampling needle tube, and the oxygen concentration in the bag was measured with a food packaging zirconia oxygen concentration meter (model number LC-750F, manufactured by Toray Engineering Co., Ltd.). Furthermore, the volume of the gas in the bag was measured, and the oxygen permeability was calculated from the following formula.
(Expression) Oxygen permeability = change in internal oxygen concentration (%) / 100 × volume (cm ³ ) × 24 × 60 / hour (360 minutes) × 10000 cm ² / area (1232 cm ² ) /0.21 (partial pressure of oxygen )
(Oxygen concentration / carbon dioxide concentration)
The measurement was performed using an O ₂ / CO ₂ analyzer, Check Mate 3, for food packaging manufactured by Dansensor.
(appearance)
The package was opened, the fruits and vegetables taken out were arranged, and the area of the entire browning portion was evaluated visually with n = 3 around the cabbage cross section.
The evaluation criteria are as follows.
A: There is no problem with no browning.
B: Although browning is slightly noticeable at 10% or less of the entire cross section C: Although browning is 30% or less of the entire cross section, it is quite conspicuous but can be sold D: Although it is browned, it is 50% or less of the entire cross section E: Remarkably conspicuous and unsaleable by consumers E: Large browning, clearly unsaleable to consumers (odor)
When the package was opened, the face was brought close to it and the inside smell was smelled, and sensory evaluation was performed with n = 3.
The evaluation criteria are as follows.
A: There is no problem in the fresh state B: There is a little smell but it can be said that it is fresh C: The state is strong but it is in the same state as the market and can be sold D: The state is more smelly and the consumer cares E: More smelly and unsaleable

(Comparative Example 1)
Two OPP (biaxially stretched polypropylene) films with a thickness of 30 μm are overlapped, three sides are sealed with heat seal and cut, and one side is unsealed packaging bag (220 mm × 240 mm, inner dimension Area: 1232 cm ² ).
<Cut cabbage>
The cabbage was soiled and the damaged portion was removed, and then cut into a width of approximately 2 mm, followed by 100 ppm and 10 minutes of hypochlorous acid cleaning based on the “Manufacturing Manual for Mass Cooking Facilities” (Ministry of Health and Welfare). Thereafter, dehydration and drying were appropriately performed to obtain cut cabbage.
The cut cabbage moisture content is 17 based on the weight loss when dried under reduced pressure at 70 ° C. for 5 hours based on “Analysis method for nutrition labeling according to nutrition labeling standards” (Consumer Agency). %Met.
150 g of cut cabbage subjected to the above treatment was sealed in a packaging container, filled with nitrogen, and then heat sealed to prepare a package. The package was stored at 10 ° C., and after 0, 24, 48, 72, 96, 120, and 144 hours, the internal oxygen concentration was measured to evaluate the appearance and smell of cut cabbage.
The oxygen transmission rate of the film was 1000 CC / m ² / atm / day.
The results are shown in Table 1.

(Comparative Example 2)
A package was prepared and evaluated in the same manner as in Comparative Example 1 except that one hole having a diameter of 100 μm was provided by laser processing on an OPP (biaxially oriented polypropylene) film.
The oxygen permeability of the film was 2000 CC / m ² / atm / day.
The results are shown in Table 1.

Example 1
A package was prepared and evaluated in the same manner as in Comparative Example 1 except that a polyethylene film having a thickness of 30 μm was used instead of the OPP (biaxially oriented polypropylene) film.
When the presence or absence of an opening in the film was observed, it was confirmed that there was no opening. The oxygen transmission rate of the film was 5000 CC / m ² / atm / day.
The results are shown in Table 1.

(Example 2)
A package was prepared and evaluated in the same manner as in Comparative Example 1 except that one needle hole having a diameter of 200 μm was provided in an OPP (biaxially oriented polypropylene) film.
The oxygen permeability of the film was 10,000 CC / m ² / atm / day.
The results are shown in Table 1.

(Example 3)
A package was prepared and evaluated in the same manner as in Comparative Example 1 except that three holes having a diameter of 200 μm were provided in an OPP (biaxially oriented polypropylene) film.
The oxygen transmission rate of the film was 15000 CC / m ² / atm / day.
The results are shown in Table 1.

Example 4
A package was prepared and evaluated in the same manner as in Comparative Example 1 except that 10 holes having a diameter of 200 μm were provided in an OPP (biaxially oriented polypropylene) film.
The oxygen permeability of the film was 30000 CC / m ² / atm / day.
The results are shown in Table 1.

(Comparative Example 3)
A package was prepared and evaluated in the same manner as in Comparative Example 2 except that a mixed gas of oxygen: 5% by volume / nitrogen: 95% by volume was used instead of nitrogen gas.
The results are shown in Table 1.

(Comparative Example 4)
A package was prepared and evaluated in the same manner as in Comparative Example 2 except that a mixed gas of oxygen: 10% by volume / nitrogen: 90% by volume was used instead of nitrogen gas.
The results are shown in Table 1.

(Comparative Example 5)
A package was prepared and evaluated in the same manner as in Comparative Example 2 except that a mixed gas of oxygen: 15% by volume / nitrogen: 85% by volume was used instead of nitrogen gas.
The results are shown in Table 1.

(Comparative Example 6)
A package was produced and evaluated in the same manner as in Comparative Example 2 except that the atmosphere was filled instead of nitrogen gas.
The results are shown in Table 1.

  In each Example in which the oxygen concentration inside the package after 72 hours from the sealing of the package was within the range specified in the present invention, it was possible to particularly effectively suppress the generation of odor while suppressing browning. did it. On the other hand, in each comparative example in which the oxygen concentration inside the package 72 hours after sealing the package was outside the range defined in the present invention, odor was already generated after 48 hours, and the commercial value of the cut cabbage was Some were damaged.

  The package of the present invention has an appropriate value for the internal oxygen concentration of the package after the lapse of a predetermined time after sealing the package, and performs cutting, washing, dehydration or drying treatment with high economic value, Since it is particularly effective for maintaining the freshness such as the suppression of odor generation of fruits and vegetables containing cabbage such as cabbage adjusted to an appropriate amount of water, it has high practical value, such as food processing, distribution, and eating out. Has high applicability in various industrial fields.

Claims (5)

Oxygen permeability is 4500 cc / m ² / atm / day / atm or more and 30000 cc / m ² / atm / day or less at 20 ° C. and 90% RH, and is a perforated stretched polypropylene film or a non-porous polyethylene system The fruit and vegetables containing cut cabbage are housed in a packaging container comprising a polymer film as a film, and the internal oxygen concentration after holding for 72 hours under the condition of 10 ° C. after sealing the package is 3. The package which is 3 volume% or more and 16.5 volume% or less. The thickness of the polymer film is a 45μm 15, the packaging body according to claim 1. The package according to claim 1 or 2 , wherein the polymer film contains at least one antibacterial agent or is coated with at least one antibacterial agent. The package according to any one of claims 1 to 3 , further comprising a hygroscopic agent and / or an antibacterial agent. Oxygen permeability is 4500 cc / m ² / atm / day / atm or more and 30000 cc / m ² / atm / day or less at 20 ° C. and 90% RH, and is a perforated stretched polypropylene film or a non-porous polyethylene system A process of storing fruits and vegetables containing cut cabbage in a packaging container comprising a polymer film as a film, and holding the package in the packaging container for 72 hours under conditions of 2 ° C. to 15 ° C. A method for maintaining the freshness of fruits and vegetables, comprising: a step of adjusting the oxygen concentration later to 3.3 % by volume to 16.5 % by volume.