JP2018199500A - Package excellent in freshness keeping performance of vegetables and fruits including chinese cabbage, and freshness keeping method of vegetables and fruits - Google Patents

Abstract

To provide a package formed by storing vegetables and fruits including a Chinese cabbage in a package container, where even when stored under refrigeration temperature at about 5°C, where the package can perform stably, for a long period, freshness keeping excellent in a total balance of four points of keeping of hue, suppression of withering, suppression of odor occurrence, and suppression of drip generation which affect merchantability of the Chinese cabbage.SOLUTION: A package is formed by storing vegetables and fruits including a Chinese cabbage in a package container including a polymeric film. In the package, when stored under a frozen state at 5°C, oxygen concentration is 5% or more and 15% or less and carbon dioxide concentration is more than 5% and less than 12%, inside the package container during a period from 3 days to 8 days after sealing of the package.SELECTED DRAWING: None

Description

  The present invention relates to a package having excellent freshness retention performance when storing fruits and vegetables containing komatsuna and stored refrigerated, and a method for maintaining the freshness thereof, and in particular, contains fruits and vegetables containing komatsuna in a packaging container having a polymer film. In particular, the present invention relates to a package body in which oxygen concentration and carbon dioxide concentration in a packaging container after a predetermined time has elapsed after packaging of the komatsuna when the refrigerator is stored at a predetermined temperature, and a method for maintaining freshness of the fruits and vegetables.

A gas permeable film that allows a gas (gas) permeation portion to be provided on a polymer film base material and allows gas such as oxygen, carbon dioxide, and water vapor to permeate from the gas permeation portion. It is suitably used as a packaging material for fresh vegetables. When such vegetables, fruits, etc. are packaged using such a gas permeable film, the oxygen concentration (for example, about 1 to 4% oxygen concentration) suitable for maintaining the freshness of vegetables and fruits as contents 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. It is used.

On the other hand, along with changes in the living environment and diversification of dietary habits due to nuclear families and co-working, convenience stores, etc., often handle fresh vegetables in a refrigerated storage state, and refrigerated distribution such as refrigerator warehouses and cold cars. There is also progress in refrigeration technology such as means and refrigerators, etc., with regard to maintaining freshness in the refrigerated storage state of fresh vegetables (especially the storage state at a refrigeration temperature of about 5 ° C.) Improvement is desired. Among them, Komatsuna, which is a leafy vegetable, is one of the fresh vegetables with high demand, like spinach, which is the same leafy vegetable, because it has a high nutritional value and a solid taste. When refrigerated storage of this komatsuna, it is possible to apply the packaging and storage method as described above, but the level of demand for merchantability of consumers and consumers is improving year by year, the level is Such a conventional technique has reached a level that is difficult to solve.
Komatsuna is the same leafy vegetable as spinach, but its appearance is similar. It has a different characteristic in terms of nutrients and the like (for example, oxalic acid is contained in spinach but not in komatsuna but calcium is more contained in komatsuna) Yes. Therefore, although it is the same leafy vegetable as spinach and looks similar, the refrigerated storage conditions suitable for spinach are not necessarily suitable for komatsuna as they are.
For these reasons, especially when refrigerated komatsuna is stored in refrigeration, it affects the merchantability of the product, maintaining the hue (in other words, suppressing yellowing), suppressing wilting, suppressing the generation of off-flavors, and drip ( Specifically, it is hoped to provide a stable and long-term preservation of freshness with excellent four-point total balance of suppressing the generation of water that elutes during thawing, etc., at a refrigerated temperature of about 5 ° C. There is the present situation that is rare. However, as far as the applicant can know, there is still no package or freshness maintaining method that can provide such freshness maintenance.

JP-A-5-168400

In the present invention, in view of the limitations of the above background art, etc., a package comprising vegetables and fruits containing komatsuna in a packaging container, even when stored at a refrigeration temperature of about 5 ° C. In other words, maintaining the freshness with an excellent total balance of four points of maintaining hue, suppressing wilting, suppressing off-flavor generation, and suppressing drip generation, It is an object to provide a package that can be stably formed for 8 days or more after sealing.
In addition, in the present invention, even when stored at a refrigeration temperature of about 5 ° C., the above four points, which affect the commercial properties of Komatsuna, maintain excellent freshness for a long period of time (specifically, after sealing) (8 days or more) It is an object to provide a method that can be stably performed.

  Therefore, as a result of intensive studies on this point, the present inventors have found that when a fruit and vegetable such as komatsuna is enclosed in a packaging container and stored at a refrigeration temperature of about 5 ° C., the packaging container after a predetermined period has elapsed since the encapsulation. If the oxygen concentration and carbon dioxide concentration in the inside are controlled within the predetermined concentration range, there are four points that affect the merchantability: retention of hue, suppression of wilting, suppression of off-flavor generation, and suppression of drip generation. It has been found that maintaining the freshness with an excellent total balance can be stably performed over a long period of time, and the present invention has been completed.

That is, the present invention
[1]
A packaging body containing fruits and vegetables containing komatsuna in a packaging container comprising a polymer film,
When refrigerated at 5 ° C,
From the 3rd day to the 8th day after sealing of the package, the package has an oxygen concentration in the package of 5% to 15% and a carbon dioxide concentration of more than 5% and less than 12%.
[2]
The oxygen permeability of the polymer film, 20 ° C., in 90% RH, or less 750cc ^/ m 2 · day · atm or more ^{7500cc / m 2 · day · atm} , the packaging body according to [1]. cc / m ² · day · atm
[3]
In [1] or [2], the oxygen permeability of the packaging container per weight of the fruits and vegetables is ^2.5 cc / m ² · g · day · atm to 25 cc / m ² · g · day · atm. The package described.
[4]
The package according to any one of [1] to [3], wherein the polymer film has a thickness of 15 μm to 45 μm.
[5]
The package according to any one of [1] to [4], wherein the polymer film is a stretched polypropylene film, a polyethylene film, or a laminate of a stretched film and a polyethylene film.
[6]
The package according to any one of [1] to [5], wherein the polymer film contains at least one antibacterial agent or is coated with at least one antibacterial agent.
[7]
A package formed by storing fruits and vegetables containing komatsuna in a packaging container including a polymer film is refrigerated at 5 ° C., and the package is sealed from the third day to the eighth day after the package is sealed. A method of maintaining the freshness of the fruits and vegetables by setting the oxygen concentration in the interior to 5% or more and 15% or less and the carbon dioxide concentration to more than 5% and less than 12%.

  According to the present invention, even when stored at a refrigerated temperature of about 5 ° C., it is possible to maintain the hue, suppress wilting, suppress the generation of off-flavors, and suppress the generation of drip with respect to komatsuna stored in the package. It is possible to stably provide freshness maintenance excellent in total point balance over a long period of at least 8 days. Therefore, according to the present invention, even when the fruits and vegetables containing the komatsuna are traded in a refrigerated storage state at about 5 ° C., an effect of having a high commercial value can be achieved.

It is a measurement result of the internal gas (oxygen concentration and carbon dioxide concentration) of various packages over time when stored at 5 ° C.

Hereinafter, modes for carrying out the present invention will be described.
The present invention is a packaging body in which fruits and vegetables containing komatsuna are stored in a packaging container comprising a polymer film, and when stored refrigerated at 5 ° C., from the third day after sealing the packaging body Until the 8th day, the package has an oxygen concentration in the package of 5% to 15% and a carbon dioxide concentration of more than 5% and less than 12%. Thus, the package of the present invention includes 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 polymer film described above, and its oxygen permeability is not particularly limited. The amount and type of fruits and vegetables to be stored and after a predetermined time has elapsed after packaging. An appropriate oxygen permeability can be selected in accordance with a desired internal oxygen concentration.
The packaging container used in the present invention preferably has an oxygen permeability of ^2.5 cc / m ² · g · day · atm or more and 25 cc / m ² · g · day · atm or less per weight of stored fruits and vegetables. It is. More preferably 3.0 cc / m ² · g · day · atm to 23 cc / m ² · g · day · atm, more preferably 3.5 cc / m ² · g · day · atm to 20 cc / m ² · g -It is below day-atm.
Further, the internal gas concentration in the packaging container can usually be adjusted by using a predetermined polymer film provided with a predetermined opening (hole), but the polymer film itself is not provided with such an opening. It is also possible to adjust using the oxygen permeability of the.

Fruits and vegetables The package of the present invention comprises fruits and vegetables containing komatsuna in the packaging container. Here, the phrase “a vegetable or vegetable includes“ komatsuna ”means to include both the case where the entire vegetable and vegetables are made of komatsuna and the case where a part of the vegetable and vegetables are made of komatsuna. Therefore, the fruits and vegetables stored in the packaging container may or may not contain other vegetables and fruits. Furthermore, as long as komatsuna is included, components other than fruits and vegetables, for example, foods other than fruits and vegetables, seasonings, food additives and the like may be included.

  “Komatsuna” constituting the package of the present invention (contained in a packaging container) is a concept that includes vegetables in general that belong to the Brassicaceae genus Brassica and are leafy vegetables that are not a kind of tsukena. Therefore, it is not limited to vegetables distributed under the name of “Komatsuna” itself, for example, “Osaki Nana”, “Meike Ichina”, “Kurona” and vegetables called “Komatsuna” Also included are “Chichimi Komatsuna” and “Shohona” made by crossing Komatsuna and cabbage.

There is no restriction | limiting in particular in the form of Komatsuna (it accommodates in a packaging container) which comprises the package body of this invention. It may be as-harvested or processed such as cut.
In addition, the komatsuna constituting the package of the present invention (stored in the packaging container) may be subjected to any or all of the processes such as washing, cooling and dehydration within the scope of the present invention. In addition, none of these processes may be performed.

  The demand for cut vegetables, called cut vegetables, has increased in recent years because they can be easily used for meals, and their commercial value is high, and thus they have high economic value. Cut komatsuna can be used for cooking as it is with other cut vegetables, and those that have been mixed with other vegetables can be used for meals easily as a salad. Have Komatsuna that constitutes the package of the present invention (that is, housed in a packaging container) can also be used in a cut form similar to other cut vegetables.

  In the present invention, when the mustard is stored in the packaging container, there is no particular limitation on other fruits and vegetables that can be stored together, and unheated or heated fruits and vegetables that can be used for food together 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, carrots, Chinese yams, burdock, root vegetables such as radish, 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 But not limited to, spinach, radish, radish, cabbage, lettuce, leafy vegetables such as asparagus, florets or seedlings.

  In this invention, there is no restriction | limiting in particular also in the form of the other fruits and vegetables which can be accommodated with a Japanese mustard spinach in a packaging container. Therefore, it may be harvested as it is, or it may be a leaf that has been separated, further separated from the leaf and stem, or cut into the desired size or shape without separating the leaf or stem. May be. In addition, the fruits and vegetables may be those that have undergone any or all of the treatments such as washing, cooling, and dehydration, and may be those that do not perform any of these treatments.

  According to the kind and form of Komatsuna (contained in a packaging container) constituting the package of the present invention, within the scope of the present invention, an oxygen permeability, and an aspect of a polymer film that gives such oxygen permeability Can be selected as appropriate. By setting these appropriately, it is possible to maintain more effective freshness within the scope of the present invention for both the above-mentioned komatsuna and the fruits and vegetables stored together.

Package Body The internal oxygen concentration and carbon dioxide concentration of the package body of the present invention are as described above. Specifically, when the package containing Komatsuna is sealed and stored at a refrigeration temperature of about 5 ° C., the oxygen concentration inside the package is 5 from the third day to the eighth day after sealing. The carbon dioxide concentration is more than 5% and less than 12%. As a result, when stored at a refrigerated temperature of about 5 ° C, Komatsuna contained in the package is excellent in total balance of four points: retention of hue, suppression of wilting, suppression of off-flavor generation, and suppression of drip generation. The freshness maintenance can be stably provided for at least 8 days. In this case, the oxygen concentration and the carbon dioxide concentration inside the package on the eighth day after the sealing are both preferably more than 5% and less than 12%, more preferably more than 6% and less than 11%.
In the present application, “%” used to represent “oxygen concentration” and “carbon dioxide concentration” is volume% unless otherwise specified.

  The temperature condition where the package of the present invention is placed is 5 ° C. in view of the actual situation of commercial transactions. However, other temperatures may be used as long as the objects and effects of the present invention can be achieved.

The oxygen concentration and carbon dioxide concentration inside the package can be specified by measuring using, for example, a gas chromatograph device GC2014 manufactured by Shimadzu Corporation.
Here, “after packaging” refers to the elapsed time since the packaging container was sealed after the vegetables and fruits containing komatsuna were stored in the packaging container. For example, “after 3 days after packaging” This refers to the state after 3 days have passed since the komatsuna was stored inside, and the packaging container was sealed (ie, after 72 hours).

  From the viewpoint of realizing the above-mentioned desired internal oxygen concentration, it is preferable that nitrogen is enclosed in the packaging container. It is because the internal oxygen concentration immediately after packaging can be kept low by sealing nitrogen at the time of sealing the packaging container. Further, nitrogen may be further encapsulated as necessary within the scope of the present invention.

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 within a predetermined value range.
Normally, 20 ° C., at ^{90% RH, 750cc / m 2} · day · atm or more 7500cc ^/ m 2 · is preferably used in day · atm or less in the ^{range, 1300cc / m 2 · day ·} atm or 6000 cc / ^{m 2} More preferably within the range of day · atm or less. More ^{preferably, 1400cc / m 2 · day ·} atm or 4000 cc ^/ m is a 2 · day · atm or less, particularly preferably not more than 1450cc ^/ m 2 · day · atm or more ^{2000cc / m 2 · day · atm} .

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.
The oxygen concentration inside the bag was measured using a gas chromatograph apparatus GC2014 manufactured by Shimadzu Corporation. 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 (2 × a × bcm 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 adjusted as appropriate.
For example, the oxygen permeability of a 30 μm OPP (biaxially oriented polypropylene) bag is 1000 cc / m ² / day / atm, but the oxygen permeability can be increased by making one hole. On the other hand, it is possible to adjust the oxygen permeability, but the mechanical strength may decrease as the diameter of the hole increases and as the number of holes increases. Therefore, it is preferable to secure a certain thickness of the film. Considering the diameter and number of such holes and the mechanical strength together, the thickness of the polymer film is preferably 15 to 45 μm, more 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, etc. of the polymer film. It is also possible not to provide an opening in.
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 polymer film is used to achieve a desired oxygen permeability. You may use together the opening provided in. 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, and 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 15 to 40 μm, still more preferably 15 to 35 μm, and particularly preferably 18 to 32 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. The thermoplastic resin includes polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyamides such as nylon-6, nylon-66, polymetaxylene adipamide, polyvinyl chloride, polyimide, 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. Further, 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. For example, it can manufacture by the method of making it 20-40 micrometers, or the method by extending | stretching each 5-10 times (25-100 times by surface magnification) to the vertical direction and a horizontal direction.
<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, the formation of condensation on the surface of the polymer film is suppressed. By suppressing the propagation of germs, the growth of germs during condensation is suppressed and the antibacterial function is exhibited.

  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.

  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.

Manufacturing method of the package, and freshness-keeping method as described above, the present invention is a packaging body formed by housing the fruits or vegetables containing Komatsuna into packaging container comprising a polymeric film, when refrigerated at 5 ° C. The package of the present invention can be produced by controlling the oxygen concentration and the carbon dioxide concentration inside the package after the lapse of a predetermined period after the sealing of the package to a predetermined concentration, respectively. One embodiment of the method for maintaining the freshness of fruits and vegetables can be implemented.
Hereinafter, an embodiment of a method for manufacturing a package according to the present invention will be described with reference to an example of manufacturing a package for maintaining freshness made of Japanese mustard spinach.

Komatsuna is appropriately cut and weighed to a predetermined amount, packed in a packaging container (not sealed on one side) containing the polymer film used in this embodiment, and the packaging container is sealed A freshness-maintaining package containing komatsuna is produced.
This komatsuna is pre-treated with water washing and dehydration as necessary.
When using cut Japanese mustard spinach, it is preferable from the viewpoint of maintaining the freshness to use a sharp blade and reduce the number of scratches on the cut surface. In addition, since the cutting area increases and the freshness maintenance becomes more difficult as the cut width is narrower, from the viewpoint of maintaining the freshness, it is preferable that the cut width is wider as long as it matches the form of demand.

If a lot of miscellaneous bacteria are attached to Komatsuna from the beginning, it becomes more difficult to maintain freshness. 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 the water adhering to the surface of Komatsuna after washing. Even if the water is drained by standing after washing, a lot of water is still attached to the surface. Therefore, it is effective to sufficiently remove water using a centrifugal dehydrator or the like.

The package for keeping freshness of fruits and vegetables of the present embodiment may be filled with nitrogen and / or deaerated after storage of fruits and vegetables including Japanese mustard vegetables and sealing of the packaging container. By carrying out 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 may be advantageous for maintaining freshness. .
In addition, from the viewpoint of improving efficiency in the process of distribution, saving space, eliminating specific gases, etc., deaeration may be performed after sealing the packaging container as necessary.

  In accordance with the method as described above, for example, after carrying out the process of storing fruits and vegetables containing komatsuna in a packaging container comprising a polymer film, 3 days after sealing the package when stored refrigerated at 5 ° C. From the eyes to the 8th day, by carrying out the process in which the carbon dioxide concentration is more than 5% and less than 12% at 5% or more and 15% or less of the inside of the packaging body in the packaging container, It is possible to stably provide freshness maintenance excellent in total balance of four points, namely, hue maintenance, suppression of wilting, suppression of off-flavor generation, and suppression of drip formation over a long period of at least 8 days.

In the package of the present invention, only the fruits and vegetables containing Japanese mustard spinach may be accommodated in the packaging container, or other members may be accommodated.
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 a natural antibacterial agent with relatively little concern about the effect on fruits and vegetables and use in the vicinity of fruits and vegetables as foods. It 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 described in detail with reference to tests conducted by the applicant and results thereof. The present invention is not limited by the following test examples in any sense.

The oxygen permeability and manufacturing method of each package used in this test are as follows.
Films having 3 and 6 holes (within a pitch interval of 210 mm) of about 100 μm were formed on a 30 μm thick antifogging biaxially stretched polypropylene (antifogging OPP) film with a hot needle, respectively.
In order to measure the oxygen permeability of the film, each bag (package) with a size of 210 mm × 150 mm was heat-sealed using each of the above-perforated film and the non-perforated film. did.
Each bag was filled with nitrogen and the initial oxygen concentration was measured. After standing for several hours, the oxygen concentration was measured again. Further, the amount of air in the bag was measured, and the oxygen permeability of each film was estimated based on the above formula for calculating the oxygen permeability. As a result, the oxygen permeability of each film, 11,690Cc in three film holes 1,623cc / ^m 2 · day, hole six film / ^m 2 · day and 1,081cc / ^{m 2} in hole-free film, -It was day.
Next, a three-sided sealed bag having a size of 300 mm × 400 mm (maximum volume: 7.1 L) is prepared using the above-described hole-punched film and the hole-free film. About 300 g of Komatsuna was packed in the top, and the upper part was heat-sealed. Among these bags, a bag using a film with three holes is package 1, a bag using a film with 6 holes is package 2, and a bag using a film without holes is package 3, and these are the measurement samples. did.
These measurement samples are stored in a refrigerator set at 5 ° C., and the following measurement is performed every day after 1 day from the enclosure, 3 days after the enclosure, 4 days after the enclosure, 7 days after the enclosure, and 8 days after the enclosure. And observation evaluation was performed.

(Measurement of oxygen concentration and carbon dioxide concentration)
Using a gas chromatograph apparatus GC2014 manufactured by Shimadzu Corporation, the oxygen concentration and carbon dioxide concentration inside each package were measured.
The results are shown in FIG.

As shown in FIG. 1, in the package 1 in which komatsuna is stored using a film with three holes, the oxygen concentration and carbon dioxide concentration inside the package are 14% oxygen concentration and 14% on the third day after sealing. Concentration 7%, 4 days after sealing, oxygen concentration 12%, carbon dioxide concentration 7%, 7 days after sealing, oxygen concentration 10%, carbon dioxide concentration 9%, and sealing On the 8th day, both the oxygen concentration and the carbon dioxide concentration were 9%.
On the other hand, in both of the package 2 using the film with 6 holes and the package 3 using the film without holes, the oxygen concentration on the third day after sealing the package exceeded 15%. The oxygen concentration and carbon dioxide concentration on the 8th day after sealing of the package 2 are 17% and 4%, respectively, and the oxygen concentration and carbon dioxide concentration on the 8th day after sealing of the packaging 3 are respectively 12% and 9%.
Therefore, when only the packaging body 1 among the packaging bodies 1 to 3 is refrigerated at 5 ° C., the oxygen concentration inside the packaging body in the packaging container from the third day to the eighth day after the packaging body is sealed. Was 5% or more and 15% or less, and the carbon dioxide concentration was confirmed to be more than 5% and less than 12%. Therefore, the packaging body 1 was designated as Example 1, and the packaging bodies 2 and 3 were designated as Comparative Examples 2 and 3, respectively.
In the observational evaluation, in addition to these packaging bodies 1 to 3, a three-sided sealed bag is created using a film without holes that is not perforated to the film used in this test, and the same amount of komatsuna is packed in the bag, The following evaluation was performed using what was made into the open system without heat-sealing the upper part as the package 4 (comparative example 3).

(Hue evaluation)
The package was opened, and the overall hue centered on the surface of the extracted Komatsuna was evaluated by n (number of samples) = 4 by visual observation.
The evaluation criteria are as follows.
○: Fresh state of dark green as a whole and high merchantability △: State that there is a change due to yellowing but there is no problem with merchantability ×: State that there is a change due to yellowing and improvement in merchantability is required

(Withering evaluation)
The package was opened, and the overall tension of the extracted Komatsuna was evaluated by n (number of samples) = 4 by three persons.
The evaluation criteria are as follows.
○: Fresh and highly productive with firmness as a whole △: Slightly deflated but no problem with merchantability ×: Slightly deflated and required to improve merchantability

(Odor evaluation)
When the package was opened, the face was brought close to the inside and smelled inside, and n (number of samples) = 4, and sensory evaluation was performed by three people.
The evaluation criteria are as follows.
○: Fresh and productive with no off-flavor △: Slightly off-flavor with no problem with commerciality ×: State with off-flavor and demand for improved product

(Drip evaluation)
The package was opened, and the occurrence of drip (moisture) centered on the surface of the pickled komatsuna was evaluated by n (number of samples) = 4 by three persons.
The evaluation criteria are as follows.
○: Fresh and highly commercial with no occurrence of drip △: Some drip is observed but there is no problem with commerciality ×: Drip is observed and improvement of commerciality is required State

Table 1 shows the results of the hue evaluation, off-flavor evaluation, wilting evaluation, and drip evaluation performed using the packaging bodies 1 to 4.

As shown in Table 1, the evaluation of hue, wilting, off-flavor, and drip of the package 1 was all good even on the eighth day after sealing. On the other hand, on the 8th day after sealing, each of the packaging bodies 2 to 4 had a wrinkle evaluation of x, and the hue evaluation was Δ for the open packaging body 4, and the packaging bodies 2 and 3. Then, all were x.
Therefore, even when only the package 1 out of the packages 1 to 4 is chilled and stored at 5 ° C., the mustard spinach contained in the package is maintained for at least 8 days after sealing, suppression of wilting, and offensive odor. It has been confirmed that it is possible to stably provide a very excellent freshness maintenance with a total balance of four points of suppression of generation and suppression of drip generation. As a result, it was confirmed that Komatsuna contained in the package 1 has very high commercial properties even in a long-term refrigerated storage condition at 5 ° C. As shown in FIG. 1, the package body is stored in a refrigerated storage at 5 ° C. Unlike the package bodies 2 to 4, the package body is packaged in the packaging container from the third day to the eighth day after the package body is sealed. The carbon dioxide concentration is more than 5% and less than 12% at 5% or more and 15% or less inside the body.
Therefore, by using the package 1 corresponding to the embodiment of the present invention, even when refrigerated at 5 ° C., there are four points of maintaining hue, suppressing wilting, suppressing the generation of off-flavor, and suppressing drip generation. It was confirmed that there was an excellent effect that it was possible to stably provide a freshness maintenance excellent in the total balance over a long period of at least 8 days.
In addition, although the present inventors performed the same experiment separately with spinach using the same package, in that case, according to the package 2 with the highest oxygen permeability corresponding to Comparative Example 1 of this test, When kept refrigerated at 5 ° C, it maintains stable freshness over 11 days with the best balance of four points: retention of hue, suppression of wilting, suppression of off-flavor generation, and suppression of drip formation. I found out that it can be provided. Considering this, it was also confirmed that Komatsuna is the same leafy vegetable as spinach and looks similar, but refrigerated storage conditions suitable for spinach are not directly applicable to Komatsuna.

  According to the present invention, even when stored at a refrigerated temperature of about 5 ° C., it is possible to maintain the hue, suppress wilting, suppress the generation of off-flavors, and suppress the generation of drip with respect to komatsuna stored in the package. Because it can provide stable freshness maintenance with excellent total point balance over a long period of at least 8 days, it has a high value in practical use in various industrial fields such as food processing, distribution, and dining out. Has high availability.

Claims (7)

A packaging body containing fruits and vegetables containing komatsuna in a packaging container comprising a polymer film,
When refrigerated at 5 ° C,
From the 3rd day to the 8th day after sealing of the package, the package has an oxygen concentration in the package of 5% to 15% and a carbon dioxide concentration of more than 5% and less than 12%. The oxygen permeability of the polymer film, 20 ° C., in 90% RH, or less 750cc ^/ m 2 · day · atm or more ^{7500cc / m 2 · day · atm} , the packaging material of claim 1. The oxygen permeability of the packaging container per weight of the fruits and vegetables is ^2.5 cc / m ² · g · day · atm or more and 25 cc / m ² · g · day · atm or less. Packaging body.   The package according to any one of claims 1 to 3, wherein the polymer film has a thickness of 15 µm to 45 µm.   The package according to any one of claims 1 to 4, wherein the polymer film is a stretched polypropylene film, a polyethylene film, or a laminate of a stretched film and a polyethylene film.   The package according to any one of claims 1 to 5, wherein the polymer film contains at least one antibacterial agent or is coated with at least one antibacterial agent.   A package formed by storing fruits and vegetables containing komatsuna in a packaging container including a polymer film is refrigerated at 5 ° C., and the package is sealed from the third day to the eighth day after the package is sealed. A method of maintaining the freshness of the fruits and vegetables by setting the oxygen concentration in the interior to 5% or more and 15% or less and the carbon dioxide concentration to more than 5% and less than 12%.