JP6636988B2 - Package suitable for maintaining freshness of fruits and vegetables including radish, and method of maintaining freshness of fruits and vegetables - Google Patents

Description

  The present invention relates to a package excellent in freshness holding performance of fruits and vegetables including radish, and more specifically, comprises storing fruits and vegetables including radish in a packaging container including a polymer film, and moisture of the radish is contained. The present invention relates to a package in which the amount and the oxygen concentration in the package are each a specific amount.

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

Among the fruits and vegetables, radish is one of the widely distributed vegetables, and the above-described package and storage method can be applied.
However, radish is one of the vegetables that easily emits an offensive odor, and its odor is also said to be strong. In particular, when processing such as cutting and grated is performed, an unpleasant odor is likely to occur, and discoloration (also referred to as “browning”) and an increase in the number of viable bacteria are likely to occur.
The generation of such off-flavors gives consumers and consumers the impression that the product quality is poor, and significantly lowers the product value and economic value. However, it could not be sufficiently suppressed, and improvement was desired.

  From such a background, with respect to the preservation of freshness of fruits and vegetables including radish, there is a strong demand for a technique capable of suppressing the generation of an unpleasant smell or browning and an increase in the number of viable bacteria of the radish for a long time, exceeding the level of the conventional technology. Was.

JP-A-5-168400

  The present invention has been made in view of the above-mentioned limitations of the background art, and is directed to a package body in which fruits and vegetables including radish are stored in a packaging container. An object of the present invention is to provide a package excellent in a freshness maintaining function of fruits and vegetables, which can suppress an increase in the number.

  As a result of intensive studies, the present inventors have controlled the water content of radish and the oxygen concentration in the package to specific amounts, respectively, in a package in which fruits and vegetables including radish are stored in a packaging container containing a polymer film. By doing so, the inventors have found that the above-mentioned problems can be solved, and have completed the present invention.

That is, the present invention
[1]
Packaging wherein fruits and vegetables including radish are stored in a packaging container including a polymer film, wherein the radish has a water content of 20% to 40% and an internal oxygen concentration of 2.0% by volume or more. body,
It is.

Hereinafter, each of [2] to [13] is one aspect or one of preferred embodiments of the present invention.
[2]
The package according to [1], wherein the internal oxygen concentration after sealing the package for 72 hours under a condition of 10 ° C. is 2.0 vol% or more and 9.0 vol% or less.
[3]
The package according to [1] or [2], wherein the internal oxygen concentration after elapse of 24 hours at 10 ° C. after sealing the package is 8% by volume or more.
[4]
The package according to any one of [1] to [3], wherein the generation of odor and browning of the radish can be suppressed for 120 hours or more at 10 ° C. after sealing of the package.
[5]
[1] to [4], wherein the viable cell count of the radish can be suppressed for 96 hours or more at 10 ° C. after sealing of the package, compared to the case where the water content of the radish is 42%. A package according to any one of the preceding claims.
[6]
Oxygen permeability of the polymer film, 20 ° C., in 90% RH, or less 500cc ^/ m 2 · atm · day or more ^{7000cc / m 2 · atm · day} , one or [5] [1] A package according to the item.
[7]
The package according to any one of [1] to [6], wherein the packaging container does not have a through hole that can be confirmed with an ink leak checker.
[8]
The package according to any one of [1] to [7], wherein the thickness of the polymer film is 15 μm or more and 45 μm or less.
[9]
The package according to any one of [1] to [8], wherein the polymer film is a stretched polypropylene film, a polyethylene-based film, or a laminate of a stretched film and a polyethylene-based film.
[10]
The package according to any one of [1] to [9], wherein the polymer film contains at least one antibacterial agent or has at least one antibacterial agent applied thereto.
[11]
The package for maintaining freshness of fruits and vegetables according to any one of [1] to [10], further containing a moisture absorbent and / or an antibacterial agent.
[12]
A step of storing fruits and vegetables including radish having a water content of 20% or more and 40% or less in a packaging container containing a polymer film, and the packaging container having an oxygen concentration of 8% by volume or more in the packaging container. And a method for maintaining freshness of fruits and vegetables, comprising a step of forming a package by sealing the package.
[13]
The method for retaining freshness of fruits and vegetables according to [12], further comprising a step of retaining the package under a condition of 2 ° C or more and 15 ° C or less.

According to the present invention, in a package containing fruits and vegetables including radish in a packaging container, the moisture content of the stored radish and the oxygen concentration in the package are controlled to specific amounts, respectively. For a long time, the off-flavor, browning and viable cell count can be effectively suppressed. Therefore, the package of the fruits and vegetables including the radish and the method for keeping freshness according to the present invention can exert an effect of being excellent in the freshness keeping function of the fruits and vegetables.
According to the present invention, in particular, regarding a package in which fruits and vegetables including radish are stored in a packaging container, after packaging the radish, an unpleasant odor that affects the commercial value for a long time at about 10 ° C. To provide a package excellent in suppressing the increase in the number of viable bacteria, and to provide a package having a high commercial value in commerce and a method for maintaining freshness of fruits and vegetables. be able to.

Hereinafter, embodiments for implementing the present invention will be described.
According to the present invention, a fruit or vegetable containing radish is stored in a packaging container containing a polymer film, wherein the water content of the radish is 20 to 40% and the oxygen concentration in the packaging container is 2.0 volume. % Or more. As described above, the package of the present invention has at least the packaging container and the fruits and vegetables stored therein.
The numerical range in the present application includes a lower limit and an upper limit unless otherwise specified. Therefore, for example, the notation “20 to 40%” means 20% or more and 40% or less unless otherwise specified.

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

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

  The packaging container used in the present invention comprises the above-described polymer film, and its oxygen permeability is not particularly limited, and the amount, type, and after a predetermined time after packaging of the fruits and vegetables to be stored are not limited. An appropriate oxygen permeability can be selected according to a desired internal oxygen concentration. Usually, at 20 ° C. and 90% RH, those having a range of 500 to 7000 cc / atm · day can be preferably used.

Fruits and Vegetables The package of the present invention contains fruits and vegetables including radish in the packaging container. Here, the expression that “the fruits and vegetables include“ radish ”includes both the case where the fruits and vegetables are entirely composed of radish and the case where some of the fruits and vegetables are composed of radish. Therefore, the fruits and vegetables stored in the packaging container may or may not include other vegetables and fruits. Furthermore, as long as it contains radish, it may contain components other than fruits and vegetables, for example, foods other than fruits and vegetables, seasonings, food additives, and the like.

The “radish” that constitutes the package of the present invention (contained in a packaging container) is a concept that includes vegetables generally belonging to the genus radish belonging to the Brassicaceae family. Not limited.
That is, the term "radish" used herein is generally known varieties such as blue radish, white radish, spicy radish, etc., but is not particularly limited to varieties and the like, and besides radish, Varieties such as radish, black radish, and Japanese radish may be used.
Further, the site of "radish" is generally a root, but is not particularly limited thereto, and may be a leaf or a stem, or a combination of these, for example, a radish with leaves. Such a thing may be used. In addition, the "radish" is not limited to a peeled one, and may include a part or all of the skin.

The radish constituting the package of the present invention (stored in the packaging container) has a water content of 20 to 40%. The water content is preferably from 25 to 40%, more preferably from 28 to 38%. The above-mentioned water content is excellent in that the generation of off-flavors and browning of radish can be suppressed for a long time, both can be achieved, and the number of viable bacteria can be suppressed.
In addition, the water content in the present application is based on the “analysis method for nutrition labeling in nutrition labeling standards” (Consumer Affairs Agency), and the sample dried under reduced pressure at 70 ° C. for 5 hours is defined as zero (starting point). Say from the weight minutes. For example, when 100 g of cut radish becomes 90 g by drying under reduced pressure at 70 ° C. for 5 hours, the water content is 10 g / 100 g = 10%.

The moisture content of the radish constituting the package of the present invention can be appropriately controlled by controlling the moisture content when storing fruits and vegetables including radish in the packaging container. In a preferred embodiment of the present invention, the package is stored under a relatively low temperature condition of, for example, 2 ° C. or more and 15 ° C. or less, and the packaging container constituting the package has, for example, an oxygen permeability of 7000 cc / m 2. constituted by relatively high gas-barrier film is ² · atm · day or less. In such a case, the water content of the radish changes with time relatively small, so by setting the water content of the radish to a desired value when housed in the packaging container, the water content of the radish in the package is reduced. The amount can be at the desired value over an extended period.
However, even when the storage temperature of the package is higher or the gas barrier property of the packaging container is lower, the change in the water content of radish can be predicted to some extent. Of radish can have a desired value over a long period of time.

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

The form of radish (contained in a packaging container) constituting the package of the present invention is not particularly limited. It may be a freshly harvested one, a so-called pre-treated one from which outer leaves and the like have been removed, or a cut form called a cut radish.
The form of the radish may be processed like cutting, grated, sliced or the like, and is not limited to these processing methods as long as the object of the present invention can be achieved.
Further, the radish (contained in the packaging container) constituting the package of the present invention may be one that has been subjected to any or all of the processing such as washing, cooling, and dehydration within the scope of the present invention. Alternatively, none of these processes may be performed.

In the present invention, when radish is stored in the packaging container, there is no particular limitation on other fruits and vegetables that can be stored together, and non-heated or heated fruits and vegetables that can be edible with the radish can be appropriately stored. Specific examples of such fruits and vegetables include fruits such as bananas, mangos, plums, apples, strawberries, oranges, grapes, Japanese pears, pears, root vegetables such as carrots, potatoes, burdock, tomatoes, cucumbers, Fruits and vegetables such as eggplant, pepper, edamame, okra, mushrooms such as mung bean sprouts, soy bean sprouts, syrup, shiitake mushrooms, shimeji mushrooms, eryngii, maitake, fungi mushrooms such as matsutake mushrooms, broccoli, spinach , Komatsuna, bok choy, cabbage, lettuce, asparagus, leafy vegetables, flowers or seedlings, but are not limited thereto.
In the case of storing radish, the form of controlling and maintaining the oxygen concentration, which is one mode of the present embodiment, is particularly effective in maintaining the freshness of a fruit or vegetable in a form of substantially breathing due to its action.

  In the present invention, the form of other fruits and vegetables that can be stored together with the radish in the packaging container is not particularly limited. Therefore, it may be a freshly harvested vegetable, a so-called pre-processed vegetable from which outer leaves and the like have been removed, or a cut vegetable called a cut vegetable. The fruits and vegetables may have been subjected to any or all of the processing such as washing, cooling, and dehydration, or may be those without any of these processings.

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

  Depending on the type and form of radish (contained in a packaging container) constituting the package of the present invention, within the scope of the present invention, the oxygen permeability and the embodiment of the polymer film providing such oxygen permeability Can be appropriately selected. By setting these appropriately, freshness can be more effectively maintained within the scope of the present invention for any of the radish and the fruits and vegetables that are stored together when present.

Package The internal oxygen concentration of the package of the present invention is 2.0 volumes or more. When the internal oxygen concentration is 2.0 volumes or more and the water content of radish is 20% or more and 40% or less, generation of off-flavor and browning is effectively suppressed for a long time, preferably for 120 hours or more. At the same time, the increase in the number of viable bacteria can be effectively suppressed for a long period of time, preferably 96 hours or more. The suppression of the number of viable bacteria was performed, for example, under the same conditions with respect to radish having a water content of 42% when the viable cell count of radish was maintained at 10 ° C. for 96 hours or more after sealing the package. It can be confirmed by being smaller than the viable cell count at that time.
The internal oxygen concentration of the package is preferably more than 2.0% by volume, more preferably 3.0% by volume or more, and particularly preferably 4.0% by volume or more.
The internal oxygen concentration of the package of the present invention has no particular upper limit, but is preferably 19.5% or less from the viewpoint of maintaining a good appearance.
The temperature conditions at which the package of the present invention is placed are not particularly limited as long as the objects of the present invention can be achieved, but are preferably 2 ° C or more and 15 ° C or less, and more preferably about 10 ° C in view of the actual conditions of commercial transactions. preferable.

  It is preferable to appropriately adjust the oxygen concentration inside the package of the present invention according to the temperature condition at which the package is placed, in order to more effectively maintain freshness. For example, when storing a cut radish in the package of the present invention, after sealing the package of the cut radish, the oxygen concentration inside the package after 3 days (72 hours) at 10 ° C. It is preferably from 2.0% by volume to 9.0% by volume, more preferably from more than 2.0% by volume to 9.0% by volume. In the package of the present invention, particularly when a packaging container having a high gas barrier property is used, the internal oxygen concentration often decreases over time due to respiration of fruits and vegetables including radish. In such a case, if the internal oxygen concentration is 2.0% by volume or more after 3 days (72 hours) at 10 ° C. after sealing the package, 3% It is highly probable that the internal oxygen concentration was 2.0% by volume or more over a period of days, and is particularly preferable from the viewpoint of maintaining the quality of fruits and vegetables, particularly preventing the generation of off-flavors.

The oxygen concentration inside the package can be specified, for example, by measuring using an O ₂ / CO ₂ analyzer for food packaging Check Mat 3 manufactured by Dansensor.
Here, "after the package is sealed" refers to the elapsed time since the packaging container was sealed after storing fruits and vegetables including radish, for example, "after the package was sealed. "72 hours" means a state 72 hours after the radish is stored in the packaging container and the packaging container is sealed.

From the viewpoint of realizing the desired internal oxygen concentration described above, the internal oxygen concentration immediately after the sealing of the package is preferably substantially higher than 2.0% by volume, for example, 10% by volume or more. Is preferred. By setting the internal oxygen concentration immediately after the sealing of the package to be substantially higher than the desired internal oxygen concentration, even if oxygen is consumed by respiration of fruits and vegetables including radish, the internal oxygen concentration will be longer after packaging. It can be maintained at a desired level over a period of time.
Since the internal oxygen concentration immediately after the sealing of the package is not stable in many cases, the initial oxygen concentration may be controlled based on the oxygen concentration 24 hours after the sealing of the package. In this case, it is preferable that the internal oxygen concentration after the sealing of the package has been passed for 24 hours at 10 ° C. is 8% by volume or more.

Polymer Film In order to realize the above-mentioned desired internal oxygen concentration, it is desirable to configure a packaging container using a polymer film having an oxygen permeability of a predetermined value or more.
That is, the lower limit of the oxygen permeability of the polymer film used in the present invention is preferably at least 500 cc / m ² · atm · day at 20 ° C. and 90% RH, and at least 1000 cc / m ² · atm · day. Is more preferable. When the oxygen permeability at 20 ° C. and 90% RH is 500 cc / m ² · atm · day or more, oxygen from outside air is introduced, and a desired internal oxygen concentration of 2.0 vol% or more can be maintained. it can. The upper limit of the oxygen permeability of the polymer film used in the present invention is not particularly limited, but from 20 ° C and 90% RH, 7000 cc / m ² · atm · day, preferably 5000 cc / m ² · atm · day or less, more preferably 3000 cc / m ² · atm · day or less, and more preferably 2000 cc / m ² · atm · day or less. It is particularly preferred that there is.

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 dimension a (cm) × b (cm) is formed by the following method.
One film is almost equally folded in half and is about 5 mm wide. The scale of the heating condition is set to 3 with an impulse sealer (manufactured by Fuji Impulse, part number Fi-200-10WK), and heat sealing is performed. One of the sides substantially perpendicular to the heat-sealed side is heat-sealed so that the side is substantially at the center, and the other side is heat-sealed except for an end of about 2 cm, which is one communicating part of the other side. (cm) x b (cm).
Next, nitrogen gas is injected from the communicating portion, and when the inside of the bag becomes saturated, almost all the gas in the bag is discharged from the communicating portion. After repeating this operation 5 times, nitrogen gas is injected to saturate the inside of the bag with nitrogen gas, and the communicating portion is heat-sealed with the impulse sealer under the same conditions. The bag saturated with nitrogen gas is left for 6 hours in a room at 22 ° C. and a relative humidity of 40% in the air (1 atm, oxygen concentration: 21%, nitrogen concentration: 79%).
The oxygen concentration inside the bag was measured using an O ₂ / CO ₂ analyzer for food packaging Check Mat 3 manufactured by Dansensor. Further, the volume of the gas in the bag is measured, and the oxygen permeability is calculated from the following equation.
(Formula) Oxygen permeability = internal oxygen concentration change (%) / 100 × volume (cm ³ ) × 24 × 60 / hour (360 minutes) × 10000 cm ² / area (a × b × 2 cm ² ) /0.21 ( Partial pressure of oxygen)

By appropriately selecting the material, thickness, processing method, and the like of the polymer film, the oxygen permeability of the polymer film can be appropriately adjusted.
For example, the oxygen permeability of a 30 μm OPP (biaxially oriented polypropylene) bag is 1000 cc / m ² · atm · day, but it becomes 2000 cc / m ² · atm · day when one 100φ hole is opened.

As described above, the oxygen permeability of the polymer film can be adjusted by appropriately selecting the material, thickness, processing method, and the like of the polymer film. It is not necessary to provide an opening in the polymer film. In particular, the oxygen permeability of 500 cc / m ² · atm · day or more at 20 ° C. and 90% RH in a preferred embodiment of the present invention can be realized without providing an opening in the polymer film.
Since it is not necessary to provide an opening in the polymer film, the manufacturing process becomes simpler and lower in cost, and it is not necessary to precisely control the size, shape, and the like of the opening.
The absence of an opening in the polymer film can be confirmed, for example, by the fact that the polymer film forming the packaging container does not have a through hole that can be confirmed by an ink leakage checker.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The present invention provides a method for manufacturing a package and a method for maintaining freshness. The present invention includes storing a fruit and vegetable including radish in a packaging container including a polymer film, and appropriately adjusting the water content of the radish when stored. Can be manufactured, and the method for maintaining freshness of fruits and vegetables, which is one embodiment of the present invention, can be performed.
Hereinafter, the method for manufacturing a package of the present invention will be described by taking a package for maintaining freshness made of cut radish as an example.

  First, in the pretreatment process of radish, it is washed well with skin. This is supplied to the conveyor. The radish conveyed by the conveyor is cut by a slicer, washed in a washing tank filled with cold water, also serving as cooling, and is sufficiently drained by a centrifugal dehydrator, drying under reduced pressure, etc. until the water content becomes 20 to 40% by volume. Dehydrated.

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

From the viewpoint of maintaining the freshness of the cut radish, it is preferable to use a sharp blade and to reduce scratches generated on the cut surface.
In addition, as the cut width is smaller, the cut area increases, and it becomes more difficult to maintain freshness. Therefore, from the viewpoint of maintaining freshness, it is preferable that the cut width is wide as long as it conforms to the form of demand.
Furthermore, if a lot of germs adhere to the cut radish from the beginning, it becomes more difficult to maintain freshness. Therefore, it is preferable to reduce the germs adhesion as much as possible by washing well. Washing is particularly effective for maintaining freshness, since it not only reduces the adhesion of various bacteria, but also has the effect of removing cell fluids and the like that contain highly active enzymes and the like and may cause discoloration.
In addition, it is important to sufficiently remove moisture adhering to the surface of the cut radish after washing in order to maintain freshness. In the cut radish of the present invention, the water content needs to be reduced to 20 to 40%. It is especially important because there is. Even if water is drained by standing after washing, much water still adheres to the surface of the cut radish, so it is effective to sufficiently remove water using a centrifugal dehydrator or the like.

In the package for keeping freshness of fruits and vegetables of the present embodiment, after storing fruits and vegetables including cut radish and sealing the packaging container, gas having a predetermined oxygen concentration, for example, an oxygen concentration of 8% by volume or more is sealed. You may. By encapsulating a gas having a predetermined oxygen concentration, it becomes possible to quickly reach a desired internal oxygen concentration designed as an equilibrium state of the oxygen permeability of the packaging container and the respiratory rate of the fruit and vegetable, and maintain freshness. It is advantageous.
In addition, degassing may be performed before and after the sealing of the packaging container from the viewpoints of improving efficiency in the distribution process, saving space, eliminating specific gas, and the like.

According to the method as described above, for example, after carrying out a step of storing fruits and vegetables including cut radish having a water content of 20 to 40% in a packaging container containing a polymer film, the oxygen concentration in the packaging container is reduced. By carrying out the step of forming a package by sealing the packaging container in a state of 8% by volume or more, freshness of fruits and vegetables including cut radish can be effectively maintained.
It is preferable that the method for maintaining freshness of fruits and vegetables further includes a step of maintaining the package under a condition of 2 ° C. or more and 15 ° C. or less. The retention time of this step is not particularly limited, but is preferably 72 hours or more, more preferably 96 hours or more, further preferably 120 hours or more, and particularly preferably 144 hours or more. preferable.

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

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

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

In the following Examples / Comparative Examples, each characteristic was evaluated by the following methods.
(With or without opening)
After injecting a red penetration liquid (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: Ageless Seal Check Spray) into the packaging container, set the heating condition scale to 3 with an impulse sealer, heat seal with a width of about 5 mm, (Kokuyo PPC paper, paper A4) was pressed, and the presence or absence of the opening was confirmed by the presence or absence of transfer of the ink to the paper.
(amount of water)
As described above, the amount of water in the radish stored in the packaging container was dried under reduced pressure at 70 ° C. for 5 hours based on “Analysis of Nutrition Labeling in Nutrition Labeling Standards” (Consumer Affairs Agency). The sample was taken as zero (starting point) to determine the weight from there. For example, when 100 g of cut radish becomes 90 g by drying under reduced pressure at 70 ° C. for 5 hours, the water content is 10 g / 100 g = 10%.
(Oxygen concentration)
The measurement was performed using an O ₂ / CO ₂ analyzer for food packaging Check Material 3 manufactured by Dansensor.
(appearance)
The package was opened, the radish was taken out, and the area of the entire browned portion was visually evaluated with n (the number of samples) = 5 around the cut cross section.
The evaluation criteria are as follows.
5: There is no problem in a fresh state. 4: There is a little browning but it can be said that it is fresh. 3: There is browning but it is in the same state as on the market, and it can be sold. 1: A state in which browning is further strong and cannot be sold In the present application, in the case of an evaluation of 2 or less, it is evaluated that browning has occurred.
(smell)
When the seal of the package was opened, the face was approached and the odor inside was smelled, and the sensory evaluation was performed with n (number of samples) = 5.
The evaluation criteria are as follows.
5: No problem at all in a fresh state 4: Slight smell but fresh state 3: Smell strong but in the same state as in the market and available for sale 2: Smell more strong and consumers care 1: A state in which the odor is further strong and cannot be sold In the present application, in the case of an evaluation of 4 or less, it is evaluated that an odor has occurred.
(Viable cell count)
On the fourth day (96 hours after packaging) of cut radish, the viable cell count was determined at 35 ° C. ± 1.0 ° C. under aerobic conditions using a standard agar medium for n (number of samples) = 5. The number (unit: CFU / g) at which colonies were observed after culturing for 48 hours ± 3 hours was calculated.

(Comparative Example 1)
Two OPP (biaxially oriented polypropylene) films each having a thickness of 30 μm are overlapped, three sides are sealed with heat sealing, and then cut. One side is an unsealed packaging bag (170 mm × 235 mm; (Area: 799 cm ² ).
When the presence or absence of an opening in the film was confirmed, it was confirmed that there was no opening.
Regarding gas permeability of the film, oxygen permeability was 1000 cc / m ² · atm · day at 20 ° C and 90% RH.
The cut radish consisted of one cut, two washes, rinsing, and three dehydration, and was prepared according to the method described in the "Manual for Mass Cooking Facility Sanitation" (Ministry of Health and Welfare). Specifically, the water content was produced 42% of the cut radish.
Approximately 50 g of cut radish having a water content of 42% was stored in a packaging container, and air was filled in the container, followed by heat sealing to prepare a package. The package was stored at 10 ° C., and the internal oxygen concentration was measured immediately after packaging the cut radish, and after 24 hours, 48 hours, 72 hours, 120 hours, and 144 hours, and the odor and appearance of the cut radish were measured. Was evaluated. Table 1 shows the results.
Further, the number of viable bacteria (unit: CFU / g) 96 hours after the packaging of the cut radish (the fourth day) was examined, and it was 3.1 × 10 ⁵ .

(Examples 1 to 4)
30 minutes each and dried under reduced pressure at 70 ° C. using a dry燥器, 60 minutes, 120 minutes, and the water content is 35% by performing 180 minutes (Example 1) 32% (Example 2), 30% (Embodiment A package was prepared in the same manner as in Comparative Example 1 except that cut radish of Example 3) and 25% (Example 4) were prepared and used, the internal oxygen concentration was measured, and the odor of cut radish was measured. And the appearance was evaluated. Table 1 shows the results.
In addition, when the viable cell count (unit: CFU / g) on the fourth day from the packaging of the cut radish of Examples 1 to 4 was examined, they were 1.2 × 10 ⁵ , 2.1 × 10 ⁵ , 1 0.1 × 10 ⁵ and 9.5 × 10 ⁴ .

In Examples 1 to 4 in which the water content of the cut radish when stored in the packaging container was in the range of 20% or more and 40% or less, the unusual odor was all effectively suppressed, and 120% after the package was sealed. Over time, the evaluation of the appearance was 3 or more, and it was confirmed that browning could be effectively suppressed.
On the other hand, in Comparative Example 1 in which the water content of the cut radish exceeds 40% when stored in a packaging container, on the fifth day (after 120 hours) from the packaging, the appearance is evaluated as 2, and the consumer is concerned. It was confirmed that such browning occurred and the commercial value was lost.
Therefore, when the water content of the cut radish when stored in the packaging container is in the range of 20% or more and 40% or less, the fifth day from the packaging (after 120 hours) in terms of both odor and appearance. However, the commercial value is not lost, but when it exceeds 40%, it is confirmed that the commercial value is lost on the fifth day (after 120 hours) from the packaging in terms of appearance.

  Furthermore, regarding the viable cell count on the fourth day (after 96 hours) from the packaging of cut radish, in Comparative Example 1 in which the moisture content of cut radish exceeds 40%, the moisture content is in the range of 20% or more and 40% or less. It was confirmed that the viable cell count was higher than that of any of the examples described in (1). Therefore, each of the examples in which the water content of the cut radish is in the range of 20% or more and 40% or less is superior to Comparative Example 1 in which the water content is more than 40% in terms of suppressing the number of viable bacteria. I understand.

  According to the present invention, in a package containing fruits and vegetables including radish having a high economic value, by controlling the water concentration in the radish to be packaged and the oxygen concentration in the package to appropriate values, Since the off-flavor, browning, and viable cell count of the fruits and vegetables can be effectively suppressed, the fruits and vegetables have a high practical value, and have high applicability in various fields of industries such as food processing, distribution, and restaurant.

Claims (9)

It houses the fruits or vegetables including radish into two states a polymer film was superposed to each other, or one fused formed by packaging container in a state where the folded polymer film, of the radish, consumption Based on the National Agency for Nutrition Labeling Analysis Method for Nutrition Labeling, etc., the state of drying under reduced pressure at 70 ° C. for 5 hours was defined as zero, and the water content as a weight component from there was 20% or more and 35% or less. The internal oxygen concentration is 2.0% by volume or more after the sealing of the package, and the internal oxygen concentration is 2.0% by volume or more after a lapse of 72 hours at 10 ° C. The following is the package. The oxygen permeability of the polymer film, 20 ° C., in 90% RH, or less 500cc ^/ m 2 · atm · day or more ^{7000cc / m 2 · atm · day} , packaging according to claim 1.   The package according to claim 1, wherein the packaging container does not have a through hole that can be confirmed by an ink leak checker.   The package according to any one of claims 1 to 3, wherein the thickness of the polymer film is 15 µm or more and 45 µm or less.   The package according to any one of claims 1 to 4, wherein the polymer film is a stretched polypropylene film, a polyethylene-based film, or a laminate of a stretched film and a polyethylene-based film.   The package according to any one of claims 1 to 5, wherein the polymer film contains at least one antibacterial agent, or has at least one antibacterial agent applied thereto.   The package for keeping freshness of fruits and vegetables according to any one of claims 1 to 6, further comprising a moisture absorbent and / or an antibacterial agent. Consumer Affairs Agency, "Analysis method of nutrition labeling etc. in nutrition labeling standards" in a packaging container obtained by fusing two polymer films on top of each other or with one polymer film folded on top of each other. A step of storing fruits and vegetables including radish having a water content of 20% or more and 35% or less as a weight component from the state where the drying under reduced pressure at 70 ° C. for 5 hours is zero , and in the packaging container. A method for maintaining the freshness of fruits and vegetables, comprising a step of forming a package by sealing the packaging container in a state where the oxygen concentration is 8% by volume or more.   The method for maintaining freshness of fruits and vegetables according to claim 8, further comprising a step of maintaining the package under a condition of 2 ° C or more and 15 ° C or less.