JP6728103B2 - Package excellent in freshness-keeping performance of fruits and vegetables containing komatsuna and method of keeping freshness of the fruits and vegetables - Google Patents

Description

The present invention relates to a package excellent in freshness retention performance when storing fruits and vegetables containing Komatsuna and refrigerating and a method for retaining the freshness thereof, and in particular, storing fruits and vegetables containing Komatsuna in a packaging container having a polymer film. The present invention relates to a package in which the oxygen concentration and the carbon dioxide concentration in a packaging container after a lapse of a predetermined time after packaging of the above-mentioned komatsuna (a kind of komatsuna) are stored in a refrigerator at a predetermined temperature and a method for maintaining freshness of the fruits and vegetables.

A gas permeable film that is provided with a gas (gas) permeable portion on a polymer film substrate and allows gas such as oxygen, carbon dioxide, and water vapor to permeate from the gas permeable portion is used in the food field for fruits and vegetables, particularly cut vegetables. It is preferably used as a packaging material for fresh vegetables. By packaging vegetables, fruits, etc. using such a gas permeable film, it is possible to maintain an oxygen concentration suitable for keeping the freshness of the contents vegetables, fruits (for example, an oxygen concentration of about 1 to 4%). It is known that the contents can be stored while keeping the freshness for a relatively long period.
For example, in Patent Document 1, in a package containing fruits and vegetables which is composed of a polymer film in which fruits and vegetables are sealed, the package is composed of (A) a perforated polymer film and (B) a non-perforated polymer film, (A), (B) at least one of the film characteristics is 25 ℃, relative humidity of 75%, the water vapor transmission rate measured under the conditions of 50 ~ 800gm ^-2 d ^{-1 based} on the effective surface area of the package There is described the packaged body containing fruits and vegetables, wherein the open area ratio of (A) is 3×10 ^{−6 to} 7×10 ⁻⁴ % with respect to the effective surface area of the packaged body. Specifically, (A) a perforated polymer film, which is made of stretched polypropylene having a thickness of 35 μm, has 95 holes with an average pore diameter of 30 μm, and has 9 holes with an average pore diameter of 60 μm. It is used.

On the other hand, due to changes in the living environment and diversification of eating habits due to the nuclear family and working together, fresh vegetables are often handled in refrigerated storage at convenience stores, etc., and refrigerated distribution such as refrigerator warehouses and cold storage cars. Due to advances in refrigerating technology such as means and refrigerators, the freshness of fresh vegetables in a refrigerated storage state (particularly in a storage state at a refrigeration temperature of about 5° C.) has a merit (that is, commercial value) with respect to freshness retention. Improvement is desired. Among them, Komatsuna, which is a leafy vegetable, is one of the fresh vegetables in high demand, like spinach, which is the same leafy vegetable, because it has a very high nutritional value and a solid taste. When refrigerating and storing this komatsuna, it is possible to apply the packaging and the storage method as described above, but the demand level for the commercial properties of consumers and consumers is improving year by year, and the level is as described above. Such a conventional technology has reached a level at which it is difficult to solve.
In addition, Komatsuna is the same leafy vegetable as spinach and looks similar, but Komatsuna is a Brassicaceae Brassica genus, whereas spinach is a spinach family Acacia subfamily Spinach genus, a completely different botany And have different characteristics in terms of nutrients (for example, oxalic acid is contained in spinach but not in komatsuna, but calcium is more contained in komatsuna). There is. Therefore, although it is a leafy vegetable similar to spinach and has a similar appearance, the refrigerated storage conditions and the like suitable for spinach are not always suitable for komatsuna.
For these reasons, especially when refrigerating and storing Komatsuna, it has an effect on its commercialability, retention of hue (in other words, suppression of yellowing), suppression of wilting, suppression of offensive odor, and drip ( Specifically, it is desirable to provide freshness preservation that is excellent in the total balance of the four points of suppressing the generation of water that elutes at the time of thawing, etc., in a storage state at a refrigerating temperature of about 5°C for a long period of time. There is a rare situation. However, as far as the applicant can know, there is still no package or a freshness keeping method capable of providing such freshness keeping.

JP-A-5-168400

In view of the limitations of the above background art, the present invention is a package in which fruits and vegetables containing komatsuna are stored in a packaging container, and even when stored at a refrigerating temperature of about 5°C, the commercial property of komatsuna ( In other words, keeping the freshness, which has an excellent total balance of four points, that is, the retention of hue, the suppression of wilting, the suppression of offensive odor, and the suppression of drip formation, which affects the commercial value), is long-term (specifically, An object is to provide a package that can be stably formed (8 days or more after sealing).
Further, according to the present invention, even when stored at a refrigerating temperature of about 5° C., the excellent freshness retention excellent in the total balance of the above-mentioned four points affecting the commercial property of Komatsuna can be achieved for a long time (specifically, after sealing). The challenge is to provide a stable method for 8 days or more.

Therefore, as a result of diligent study on this point, the present inventors have found that when vegetables and fruits such as komatsuna are enclosed in a packaging container and then stored at a refrigerating temperature of about 5° C., the packaging container after a predetermined period has elapsed from the encapsulation. If the oxygen concentration and the carbon dioxide concentration in each are controlled within a predetermined concentration range, the product properties will be affected, the retention of hue, suppression of wilting, suppression of offensive odor, and suppression of drip formation. The present invention has been completed by finding that it is possible to maintain freshness excellent in total balance stably for a long period of time.

That is, the present invention is
[1]
A packaging body in which fruits and vegetables containing komatsuna are stored in a packaging container containing a polymer film,
When stored refrigerated at 5℃,
A package in which the oxygen concentration inside the package is 5% or more and 15% or less and the carbon dioxide concentration is more than 5% and less than 12% from the 3rd day to the 8th day after the packaging of the package.
[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]
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, in [1] or [2] The package described.
[4]
The package according to any one of [1] to [3], wherein the polymer film has a thickness of 15 μm or more and 45 μm or less.
[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 in which fruits and vegetables containing komatsuna (green mustard spinach) are stored in a packaging container containing a polymer film is refrigerated at 5° C., and the package is sealed for 3 to 8 days after sealing. A method for maintaining the freshness of the above-mentioned 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 refrigerating temperature of about 5° C., the Komatsuna stored in the packaging body retains hue, suppresses wilting, suppresses offensive odor, and suppresses drip formation. It is possible to stably provide freshness retention excellent in total balance of points over a long period of at least 8 days. Therefore, according to the present invention, it is possible to obtain the effect of having a high commercial value even when the fruits and vegetables containing the Japanese mustard spinach are traded in a refrigerated storage state at about 5°C.

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 relates to a package in which fruits and vegetables containing komatsuna (green mustard spinach) are stored in a packaging container containing a polymer film, and when stored refrigerated at 5° C., from the third day after the sealing of the package. Until the 8th day, the package has an oxygen concentration of 5% or more and 15% or less and a carbon dioxide concentration of more than 5% and less than 12%. As described above, the package of the present invention has at least the packaging container and the fruits and vegetables stored therein.

Packaging Container The packaging container constituting the package of the present invention comprises a polymer film. Here, "comprising a polymer film" refers to a case where the entire packaging container is made of a polymer film, and a case where a part of the packaging container such as the lid material is made of a polymer film. The purpose is to include both.
Therefore, the packaging container may be a flexible packaging container, a so-called packaging bag, which is wholly or principally 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 other than the above are combined, or a packaging container in which a flexible polymer film and a rigid member are combined, for example, as a lid material. The molecular film may be combined with a rigid member such as a tray or a cup.

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

The packaging container used in the present invention comprises the above-described polymer film, and the oxygen permeability thereof is not particularly limited, and the amount of fruits and vegetables to be stored, the type and a predetermined time after packaging have elapsed. An appropriate oxygen permeability can be selected according to the 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. Is. More preferably 3.0 cc/m ² ·g·day·atm or more and 23 cc/m ² ·g·day·atm or less, further preferably 3.5 cc/m ² ·g·day·atm or more 20 cc/m ² ·g -Day or atm or less.
Moreover, the internal gas concentration in the packaging container can be adjusted by using a predetermined polymer film having a predetermined opening (hole), but the polymer film itself can be provided without providing such an opening. It is also possible to make adjustments by utilizing the oxygen permeability of the.

Fruits and vegetables The package of the present invention contains fruits and vegetables containing Japanese mustard spinach in the packaging container. Here, the phrase “the fruit and vegetables include “Komatsuna” includes both the case where the whole fruit and vegetables are composed of Komatsuna and the case where a part of the fruit and vegetables is composed of Komatsuna. Therefore, the fruits and vegetables stored in the packaging container may or may not contain other vegetables, fruits, or the like. Further, as long as it contains komatsuna, it may contain components other than fruits and vegetables, for example, foods other than fruits and vegetables, seasonings, food additives and the like.

In addition, "Komatsuna" that constitutes the package of the present invention (stored in a packaging container) is a concept that includes vegetables in general that are leaf vegetables that belong to the Brassicaceae genus Brassica and are one of the lacquer species that do not form a head. Therefore, it is not limited to the vegetables distributed under the name of "Komatsuna" itself. For example, the vegetables called "Osakina", "Meikena", "Kurosai", and vegetables called Komatsuna and Chijiminina were crossed. It also includes "Chimi Komatsuna" and what is called "Chibasai", which is a mixture of Komatsuna and cabbage.

There is no particular limitation on the form of the mustard spinach that constitutes the package of the present invention (stored in a packaging container). It may be as-harvested or may be processed such as cut.
Further, the komatsuna (contained in the packaging container) that constitutes the package of the present invention may be one that has undergone any or all of the treatments such as washing, cooling and dehydration within the scope of the present invention. Moreover, it is also possible to perform neither of these processes.

Demand for cut vegetables called cut vegetables has been increasing in recent years because they can be easily served for meals, and their commercial value is high, which in turn has high economic value. Just like other cut vegetables, cut Japanese mustard spinach can be used as it is for cooking, and the one mixed with other vegetables can be easily served as a salad, etc., so it has a high economic value. Have. Komatsuna that constitutes the package of the present invention (that is, is stored in a packaging container) can also be used in a pre-cut form similar to other cut vegetables.

In the present invention, when Komatsuna 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 with Komatsuna can be appropriately stored. Specific examples of such fruits and vegetables include fruits such as banana, mango, plum, apple, strawberry, mandarin orange, grape, Japanese pear, pear, carrot, Chinese yam, burdock root vegetable such as radish, tomato, Fruit vegetables such as cucumber, eggplant, bell pepper, edamame, okra, mung bean sprouts, soy bean sprouts, buds such as tokyo, mushrooms (mushrooms) such as shiitake, shimeji mushrooms, eringi, maitake, matsutake, and broccoli. Examples include, but are not limited to, spinach, radish, bok choy, cabbage, lettuce, foliage vegetables such as asparagus, flowers or seedlings.

In the present invention, there is no particular limitation on the form of other fruits and vegetables that can be stored together with komatsuna in the packaging container. Therefore, it may be as-harvested, or it may be the leaves separated, the leaves and stems may be separated, or the leaves and stems may be cut into the desired size and shape without separation. May be. In addition, the fruits and vegetables may have been subjected to any or all of the treatments such as washing, cooling and dehydration, or may not be subjected to any of these treatments.

Within the scope of the present invention, depending on the type and form of the Komatsuna that constitutes the package of the present invention (stored in a packaging container), the oxygen permeability is within the scope of the present invention, and an embodiment of a polymer film that gives such oxygen permeability Can be selected appropriately. By appropriately setting these, more effective freshness retention can be performed within the scope of the present invention for both the above-mentioned Komatsuna and the fruits and vegetables to be stored together when present.

Package The internal oxygen concentration and carbon dioxide concentration of the package of the present invention are as described above. Specifically, when the package containing Komatsuna is sealed and then stored at a refrigerating temperature of about 5° C., the oxygen concentration inside the package is 5 to 3 days after the sealing. % And 15% or less, the carbon dioxide concentration is more than 5% and less than 12%. As a result, when stored at a refrigerating temperature of about 5° C., the komatsuna stored in the package has an excellent total balance of four points: retention of hue, suppression of wilting, suppression of offensive odor, and suppression of drip formation. It is possible to stably provide freshness preservation for at least 8 days. In this case, both the oxygen concentration and the carbon dioxide concentration inside the package on the 8th day after the sealing are preferably more than 5% and less than 12%, and more preferably more than 6% and less than 11%.
In the present application, the% indication used to represent the “oxygen concentration” and the “carbon dioxide concentration” is volume% unless otherwise specified.

The temperature condition in which the package of the present invention is placed is 5°C in consideration 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 the carbon dioxide concentration inside the package can be specified, for example, by measuring with a gas chromatograph GC2014 manufactured by Shimadzu Corporation.
Here, "after packaging" refers to the elapsed time from the time when the fruits and vegetables containing komatsuna are stored in the packaging container and then the packaging container is sealed. For example, "3 days after packaging" means the packaging container. It means the state after 3 days have passed (that is, after 72 hours have passed) since the packaging container was sealed after storing the mustard spinach.

From the viewpoint of achieving the desired internal oxygen concentration described above, it is preferable that nitrogen is enclosed in the packaging container. This is because by enclosing nitrogen in the packaging container, the internal oxygen concentration immediately after packaging can be kept low. Further, if necessary, nitrogen may be further enclosed within the scope of the present invention.

Polymer Film Further , in order to realize the above-mentioned 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 · are preferably used in day · atm or less in the ^{range, 1300cc / m 2 · day ·} atm or 6000 cc / ^{m 2} -It is more preferable that it is 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 of a (cm) x b (cm) is formed by the following method.
Fold one film into two almost evenly and set the scale of heating conditions to 3 with an impulse sealer (manufactured by Fuji Impulse Co., product number Fi-200-10WK) with a width of about 5 mm, and heat seal the film. Heat seal one entire side that is substantially perpendicular to the heat-sealed side so that the side is almost in the center, and the entire side except for about 2 cm of the end that is one of the communicating sides of the other side. A bag of (cm) x b (cm) is formed.
Next, nitrogen gas is injected from the communication section, and when the inside of the bag becomes saturated, almost all the gas in the bag is discharged from the communication section. After repeating this operation 5 times, nitrogen gas is injected to saturate the inside of the bag with nitrogen gas, and the communication part is heat-sealed under the same conditions with the impulse sealer. The bag saturated with nitrogen gas is left for 6 hours in a room at 22° C. and 40% relative humidity in air (1 atm, oxygen concentration: 21%, nitrogen concentration: 79%).
The oxygen concentration inside the bag was measured using a gas chromatograph GC2014 manufactured by Shimadzu Corporation. Further, the volume of gas in the bag is measured, and the oxygen permeability is calculated from the following formula.
(Equation) Oxygen permeability=internal oxygen concentration change (%)/100×volume (cm ³ )×24×60/hour (360 minutes)×10000 cm ² /area (2×a×bcm ² )/0.21( Partial pressure of oxygen)

The oxygen permeability of the polymer film can be appropriately adjusted by appropriately selecting the material, thickness, processing method, and the like of the polymer film.
For example, the oxygen permeability of an OPP (biaxially oriented polypropylene) bag of 30 μm is 1000 cc/m ² /day/atm, but the oxygen permeability can be increased by forming one hole. On the other hand, although it becomes possible to adjust the oxygen permeability, the mechanical strength may decrease as the diameter of the pores increases or the number of pores increases. Therefore, it is preferable to secure a certain thickness of the film. Considering the diameter and number of such holes, the mechanical strength, etc., 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 by, for example, the polymer film forming the packaging container having no through hole which can be confirmed by an ink leakage checker.

On the other hand, in an embodiment of the present invention, in order to achieve a desired oxygen permeability, such as when a thick polymer film or a polymer material with low oxygen permeability needs to be used, the polymer film You may use together the opening provided in. The shape of the opening is not particularly limited, and may be circular, substantially circular, or slit-shaped. 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 matter from entering.
The size of each opening and the number of openings can be appropriately set and changed as long as the oxygen permeability of the polymer film is appropriate, and in that case, the openings occupying the effective area of the polymer film. The number of is a guide. For example, in the case of a slit-shaped opening having a length of 2 mm, the width as a through-hole cannot be visually recognized by observation with an optical microscope (manufactured by Olympus, model SZH-131) at a magnification of 4 times in a closed state. When one is provided, it has an effect of increasing the oxygen permeability of about 1000 cc/m ² ·day·atm for each 200 mm×200 mm packaging container, and the packaging required based on such knowledge. It is preferable to determine the number of slit openings from the oxygen permeability of the entire container.

The thickness of the polymer film used in the present invention is not particularly limited, and suitable oxygen permeability, flexibility when forming a packaging container, strength, transparency, economical efficiency, etc. From the viewpoint of accuracy and easiness in forming the portion, etc., a suitable thickness may be appropriately selected 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, further preferably 15 to 35 μm, and particularly preferably 18 to 32 μm. ..

The material of the polymer film is not particularly limited, but the polymer used in the conventional film for packaging fruits and vegetables can be appropriately used. 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, a natural polymer such as cellophane can be used. Further, any one of these materials may be used alone, or a plurality of these materials may be blended and/or laminated.

From the viewpoint of ease of processing and cost, the material of the polymer film is preferably a thermoplastic resin. Examples of the thermoplastic resin include homopolymers or copolymers of α-olefins such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene. Specifically, high-pressure low density polyethylene, linear low density polyethylene (LLDPE), high density polyethylene and other ethylene polymers, propylene homopolymers, propylene/α-olefin random copolymers, propylene block copolymers. And propylene polymers such as poly-1-butene, and polyolefins such as 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, ethylene acetic acid. Examples thereof include vinyl copolymers or saponified products thereof, polyvinyl alcohol, polyacrylonitrile, polycarbonate, polystyrene, ionomers, polylactic acid, polybutylene succinate, and other biodegradable resins, 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 have excellent rigidity and transparency. Further, as the thermoplastic resin, ethylene-based polymers and propylene-based polymers are more preferable because they are lightweight and have excellent film processability, and propylene-based polymers are more preferable from the viewpoint of flexibility and transparency.

<Propylene polymer>
As the propylene-based polymer, propylene homopolymer (also called homo PP), which is manufactured and sold under the name of polypropylene, propylene/α-olefin random copolymer (also called random PP). , A crystalline polymer containing propylene as a main component, such as a mixture of a propylene homopolymer and a low crystalline or amorphous propylene/ethylene random copolymer (also referred to as block PP). .. The propylene-based polymer may be a mixture of propylene homopolymers having different molecular weights, and includes 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-based polymer include polypropylene, propylene/ethylene copolymer, propylene/ethylene/1-butene copolymer, propylene/1-butene copolymer, propylene/1-pentene copolymer. , A propylene/1-hexene copolymer, a propylene/1-octene copolymer, etc. as a main monomer, and a copolymerization of this with at least one or more selected from ethylene and α-olefins having 4 to 10 carbon atoms. An example is coalescence. These may be used alone or in combination of two or more.

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

<Ethylene polymer>
As the ethylene-based polymer, a homopolymer of ethylene, a copolymer containing ethylene as a main monomer and at least one α-olefin having 3 to 8 carbon atoms, an ethylene-vinyl acetate copolymer, Saponified products 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 of the copolymer include a copolymer and ethylene/1-octene copolymer as a main monomer, and a copolymer of ethylene and at least one or more 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 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-based polymer may be a homopolymer of ethylene or a polymer mainly composed of ethylene such as LLDPE.

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

The blend and/or the laminate may be a blend and/or a laminate of any of the above-mentioned polymers, and any of the above-mentioned polymers and a material other than the polymer may be used. May be a blend and/or a laminate. That is, a polymer film is a material other than a polymer, for example, 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, dyes, etc., it may contain various fillers such as talc, silica, diatomaceous earth, etc., or may be a laminate of a polymer film and metal foil, paper, nonwoven fabric, etc.

The polymer film forming the packaging container in the present invention may be either a non-stretched film or a stretched film.
From the viewpoint of mechanical strength and the like, stretched films of various polymers can be preferably used.
In particular, a stretched film using a propylene-based polymer (stretched polypropylene film) is excellent in mechanical strength, transparency, heat resistance and the like, and thus can be particularly preferably used in the packaging container used in the present invention.
Further, the film using an ethylene polymer (polyethylene film) may be either a non-stretched film or a stretched film, but from the viewpoint of heat sealability and the like, a non-stretched film is particularly preferably used. be able to.
Examples of particularly preferable polymer films constituting the packaging container in the present invention include a stretched polypropylene film, a polyethylene film, and a laminate of a stretched film and a 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. When a biaxially stretched film is obtained as a stretched polypropylene film, it can be easily produced 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 8 to 10 times in the transverse direction by using a tenter mechanism to obtain the final film thickness. For example, it can be manufactured by a method of setting the thickness to 20 to 40 μm, or a method of stretching by 5 to 10 times (25 to 100 times in area 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. Although various known molding methods can be used for the polyethylene-based film, cast molding by extrusion with an extruder is preferable from the viewpoint of production efficiency.

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

<Laminate of stretched film and polyethylene film>
The laminate of the stretched film and the polyethylene film preferably used in the present invention is obtained by laminating the layer of the polyethylene film and the layer of the stretched film. The polyethylene film may be stretched in one direction or in two directions, but it is preferably an unstretched film from the viewpoint of stability of mechanical strength of the packaging bag.
From the viewpoint of adhesion stability, it is necessary to perform a corona treatment on the surface of the stretched film on which the adhesive is applied. preferable. Specifically, the surface tension of the film surface after the corona treatment is preferably 35 mN/m or more, and more preferably 40 mN/m or more, from the viewpoint of adhesion stability.

In addition, these polymer films may be subjected to stretching processing, anti-fog processing or printing, and inorganic antibacterial agents such as silver and copper, and organic antibacterial agents such as chitin, chitosan and allyl isothiocyanate. The agent may be applied, or these may be kneaded into 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.
In addition, a specific amount of a specific surfactant is present on the surface of the polymer film, or the specific amount of the specific surfactant is included in the polymer film, so that the polymer film may have an antibacterial function. For example, at least one compound selected from the group consisting of palmityldiethanolamine, stearyldiethanolamine, glycerin monolaurate and diglycerin monolaurate is preferably present on at least one surface of the polymer film, It is particularly preferred that one compound is present in an amount of 0.002-0.5 g/m ² . Alternatively, the polymer film preferably contains at least one compound selected from the group consisting of palmityldiethanolamine, stearyldiethanolamine, glycerin monolaurate and glycerin monocaprate, and 0.001 to 3 parts by mass. It is particularly preferable to contain.
The presence of a specific amount of a specific surfactant on the surface of the polymer film, or the polymer film contains a specific amount of a specific surfactant, the formation of dew condensation on the surface of the polymer film is suppressed. By suppressing the growth of various bacteria, the growth of various bacteria in dew condensation is suppressed and the antibacterial function is exerted.

From the viewpoint of transparency, flexibility, cost, etc., it is particularly preferable to use a stretched polypropylene film, which has been widely used in the related art, or a laminate of a stretched polypropylene film and a polyethylene-based film as a polymer film. .. Since these films are generally excellent in heat sealability, they have good productivity 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. For example, a cellophane film coated with an acrylic resin, a film obtained by laminating polyethylene terephthalate (PET) with linear low-density polyethylene (LLDPE) polystyrene and EVA can be used, 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 packaging is sealed, to produce the package of the present invention. The freshness preservation method for fruits and vegetables which is one embodiment can be carried out.
Hereinafter, one embodiment of the method for producing a package of the present invention will be described with reference to an example of production of a package for freshness preservation made of Komatsuna.

Komatsuna is appropriately cut and weighed to a predetermined amount, packed in a packaging container (one side not sealed) containing the polymer film used in the present embodiment, and the packaging container is sealed. A freshness-keeping package containing (packaged) komatsuna is produced.
If necessary, this komatsuna is subjected to pretreatments such as washing with water and dehydration.
When the cut Komatsuna is used, from the viewpoint of maintaining its freshness, it is preferable to use a sharp blade to reduce scratches on the cut surface. It should be noted that the narrower the cut width, the larger the cutting area and the more difficult it becomes to maintain the freshness. Therefore, from the viewpoint of keeping the freshness, the wider the cut width is, as long as it meets the demand form.

It is more difficult to maintain the freshness of the komatsuna if a large amount of bacteria are attached to the komatsuna from the beginning, so it is preferable to thoroughly wash the komatsuna to reduce the adhesion of bacteria. Washing is particularly effective for maintaining freshness because it not only reduces the attachment of bacteria, but also has the effect of removing cell fluid and the like that contains highly active enzymes and may cause discoloration.
In addition, it is important for keeping the freshness to sufficiently remove water adhering to the surface of Komatsuna after washing. Even if it is left standing after washing and drained, a large amount of water still adheres to the surface in many cases, so it is effective to sufficiently remove water using a centrifugal dehydrator or the like.

The package for freshness maintenance of fruits and vegetables of the present embodiment may be filled with nitrogen and/or deaerated after storing fruits and vegetables containing komatsuna and sealing the packaging container. By enclosing and/or degassing nitrogen, 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 keeping freshness. ..
Further, from the viewpoints of improving efficiency in the distribution process, saving space, and eliminating a specific gas, degassing may be performed after sealing the packaging container, if necessary.

According to the method as described above, for example, after carrying out the step of storing fruits and vegetables containing komatsuna in a packaging container containing a polymer film, when the product is refrigerated and stored at 5° C., 3 days after the packaging is sealed. From the 8th day to the 8th day, by performing a step in which the carbon dioxide concentration is 5% or more and 15% or less and the carbon dioxide concentration is more than 5% and less than 12% in the package in the packaging container, the fruits and vegetables containing the Japanese mustard spinach, It is possible to stably provide freshness retention excellent in a total balance of four points, that is, retention of hue, suppression of wilting, suppression of offensive odor generation, and suppression of drip formation, for a long period of at least 8 days.

In the package of the present invention, only fruits and vegetables containing komatsuna (green mustard spinach) may be stored in the packaging container, or other members may be stored.
For example, in addition to fruits and vegetables, a hygroscopic agent and/or an antibacterial agent may be contained in the packaging container.
The hygroscopic agent is not particularly limited, and known or commercially available materials having a hygroscopic effect or a humidity adjusting 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 burnt alum, or a mixture thereof. Examples include, but are not limited to:
Among these, it is particularly preferable to use activated carbon, which has relatively little concern about effects on fruits and vegetables and use near fruits and vegetables as foods. The activated carbon may be powdery or granular, and the raw material may be coconut shell, sawdust, charcoal, bamboo charcoal, lignite, peat, rice, petroleum pitch, or any other material. It is desirable that the activated carbon be packed in a unit such as a non-woven fabric, cellophane, paper or the like, but the activated carbon itself may be in a fibrous form. As the wrapping material for the activated carbon, it is preferable to use one having a heat-sealing property, such as a nonwoven fabric made of a synthetic resin, but as long as it has water vapor permeability and the activated carbon does not spill, it may be paper, natural fiber, or the like. no problem.

There is no particular limitation on the antibacterial agent, and substances 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 the use near foods such as fruits and vegetables should be used. It can be preferably used. More specifically, natural antibacterial agents such as chitosan, allyl isothiocyanate, hinokitiol, limonene can be stored in the packaging container.

Hereinafter, the present invention will be specifically described with reference to the tests conducted by the applicant and the results thereof. The present invention is not limited to the following test examples in any sense.

The oxygen permeability and manufacturing method of each package used in this test are as follows.
A film having 3 and 6 holes (within 210 mm pitch intervals) of about 100 μm was prepared with a hot needle on a 30 μm thick anti-fog biaxially oriented polypropylene (anti-fog OPP) film, respectively.
In order to measure the oxygen permeability of the film, it was prepared by heat-sealing each bag (packaging body) of 210 mm x 150 mm size using the above-mentioned perforated film and the non-perforated film without perforation processing. did.
Then, each bag was filled with nitrogen and the initial oxygen concentration was measured. After being left 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 calculation 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 a day.
Next, using the perforated film and the non-perforated film, a three-sided sealed bag with a size of 300 mm × 400 mm (maximum volume: 7.1 L) was created, and each bag was Approximately 300 g of Komatsuna was packed in, and the upper portion was heat sealed. Of these bags, a bag using a film with 3 holes was used as a packaging body 1, a bag using a film with 6 holes was used as a packaging body 2, and a bag using a film without holes was used as a packaging body 3, and these were used as measurement samples. did.
Then, these measurement samples were stored in a refrigerator set at 5° C., and the following measurements were taken 1 day after the encapsulation, 3 days after the encapsulation, 4 days after the encapsulation, 7 days after the encapsulation, and 8 days after the encapsulation. And observation and evaluation were performed.

(Measurement of oxygen concentration and carbon dioxide concentration)
Using a gas chromatograph GC2014 manufactured by Shimadzu Corporation, the oxygen concentration and carbon dioxide concentration inside each package were measured.
The results are shown in Fig. 1.

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

(Hue evaluation)
The package was unsealed, and the overall hue centering on the surface of the Komatsuna taken out was evaluated visually by three persons with n (number of samples)=4.
The evaluation criteria are as follows.
○: Overall dark green fresh and highly commercialized △: Some change due to yellowing but no problem in commerciality ×: Some change due to yellowing and demand for improved commercialability

(Withered evaluation)
After the package was unsealed, the overall tension of the Komatsuna that was taken out was visually evaluated by three persons with n (number of samples)=4.
The evaluation criteria are as follows.
○: Fresh and highly productive with a high degree of tension △: Slightly withered but not problematic in productability ×: Appearance of witheredness and demand for improved productability

(Unusual odor evaluation)
When the seal of the package was opened, the face was brought close to the body to smell the inside, and n (number of samples)=4, and sensory evaluation was performed by three persons.
The evaluation criteria are as follows.
○: Fresh and highly commercial product with no offensive odor △: Product with no offensive odor but no problem in commercial product ×: Product with unpleasant odor and demand for improved commercial product

(Drip evaluation)
After the package was unsealed, the occurrence of drip (water) around the surface of the Komatsuna taken out was visually evaluated by three persons with n (number of samples)=4.
The evaluation criteria are as follows.
◯: Fresh and highly commercial product with no dripping observed Δ: Slight dripping observed but no problem in commercial merchandising ×: Drip observable, demanding improvement in commercial merits State

Table 1 shows the results of the hue evaluation, the offensive odor evaluation, the wilt evaluation, and the drip evaluation performed using the packages 1 to 4.

As shown in Table 1, in the package 1, even on the eighth day after the sealing, the evaluations of hue, wilting, offensive odor, and drip were all good. On the other hand, in all of the packages 2 to 4, on the 8th day after the sealing, the evaluation of shrinkage is x, and the hue is also evaluated as Δ in the open type package 4 and the packages 2 and 3 Then all were x.
Therefore, even if only the package 1 out of the packages 1 to 4 stores the komatsuna stored in the package refrigerated at 5° C. for at least 8 days after the sealing, retains hue, suppresses wilting, and gives off odor. It was confirmed that it is possible to stably provide extremely excellent freshness retention in the total balance of the four points of suppressing the generation and suppressing the drip formation. As a result, it was confirmed that the komatsuna stored in the package 1 had a very high commercial value even in a long-term refrigerated storage state at 5°C. As shown in FIG. 1, this package is different from the packages 2 to 4 when it is stored in a refrigerator at 5° C., and the package in the packaging container is sealed from the third day to the eighth day after the packaging is sealed. At 5% or more and 15% or less inside the body, the carbon dioxide concentration is more than 5% and less than 12%.
Therefore, by using the packaging body 1 corresponding to the embodiment of the present invention, even when the packaging body 1 is refrigerated and stored at 5° C., the four points of retaining hue, suppressing wilting, suppressing offensive odor, and suppressing drip formation are four points. It was confirmed that the excellent effect of being able to stably provide the freshness retention extremely excellent in the total balance of the above for a long period of at least 8 days was obtained.
In addition, the present inventors conducted a similar experiment with spinach using the same packaging, but in that case, according to the packaging 2 having the highest oxygen permeability corresponding to Comparative Example 1 of this test. When stored refrigerated at 5°C, the best balance of freshness is maintained for 11 days with a total balance of four points: retention of hue, suppression of wilting, suppression of offensive odor generation, and suppression of drip formation. We found that we can provide. Based on this, it was also confirmed that, although Komatsuna is the same leafy vegetable as spinach and has a similar appearance, the refrigerated storage conditions suitable for spinach cannot be directly applied to Komatsuna.

According to the present invention, even when stored at a refrigerating temperature of about 5° C., the Komatsuna stored in the packaging body retains hue, suppresses wilting, suppresses offensive odor, and suppresses drip formation. Since it is possible to provide stable freshness excellent in total balance of points for a long time of at least 8 days, it has high practical value and is used in various fields of industry such as food processing, distribution, and restaurant. Has high availability.

Claims (7)

Look including a polymer film, by housing the fruits or vegetables containing Komatsuna the polymeric film state superposed two sheets to each other or the polymer film one state formed by fusing the packaging container with folded, Which is a package
When stored refrigerated at 5℃,
A package in which the oxygen concentration inside the package is 9% or more and 14% or less and the carbon dioxide concentration is 7% or more and 9% or less from the 3rd day to the 8th day after the packaging is sealed. The oxygen permeability of the polymer film, 20 ° C., in 90% RH, or less 1450cc ^/ m 2 · day · atm or more ^{2000cc / 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 3.5 cc/m ² ·g·day·atm or more and 20 cc/m ² ·g·day·atm or less, according to claim 1 or 2. Packaging. The package according to claim 1, wherein the polymer film has a thickness of 15 μm or more and 45 μm or less. 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. Look including a polymer film, by housing the fruits or vegetables containing Komatsuna the polymeric film state superposed two sheets to each other or the polymer film one state formed by fusing the packaging container with folded, The resulting package is refrigerated at 5° C., and the oxygen concentration inside the package is 9% or more and 14% or less and the carbon dioxide concentration is 7% from the 3rd day to the 8th day after the packaging is sealed. The method of maintaining the freshness of the said fruits and vegetables by making it 9% or more above.