JPH09201183A - Food storage tool and packaged food using the same - Google Patents

Abstract

(57) [Abstract] [Problem] While effectively obtaining the effect of maintaining the freshness of food,
The size and weight of the food storage tool are reduced, and the risk of leakage or accidental ingestion of the contents of the food storage tool is reduced. SOLUTION: A N-vinylcarboxylic acid amide-based liquid absorbent containing a repeating unit represented by the following general formula (I) is used as a freshness-retaining agent obtained by absorbing ethyl alcohol or an aqueous solution thereof. The food storage tool is housed in a container made of a material permeable to alcohol gas. The food storage tool is stored together with the food in a packaging material made of a material that is impervious to ethyl alcohol gas. Embedded image

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a food storage tool using ethyl alcohol gas and a packaged food using the same.

[0002]

2. Description of the Related Art It has long been known that ethyl alcohol has a disinfecting and bactericidal action, and a technique relating to the preservation of foods using this, that is, a prior art of the present invention is Japanese Patent Publication No. 55-2273. Kosho 59-300
72 and Japanese Patent Publication No. 63-52872.

Is a joint applicant of the present invention, in which an adsorbent obtained by adsorbing ethyl alcohol on an adsorbent is present together with the food in a food packaging material to alter the food. Disclosed are a food storage method and a food storage tool which are protected from mold and spoilage. Using this technique, a powdery adsorbent obtained by adsorbing 1.5 to 1.8 times by weight of ethyl alcohol to silicon dioxide fine powder or vermiculite was filled in a small bag permeable to ethyl alcohol gas. Food preservation tools are commercially available. Is a patent application filed by the present applicant, which discloses a food preservation tool in which liquid ethyl alcohol or powder wet with ethyl alcohol is enclosed in a container made of an ethyl alcohol gas permeable film. Has been done. Is also filed by the present applicant, and discloses a food preservation tool in which a gel-like ethyl alcohol is enclosed in a container made of an ethyl alcohol gas permeable film.

[0004]

In the food storage device disclosed above, an adsorbent having a relatively low bulk specific gravity and a high adsorbability has been used as the adsorbent. Is required to be about 0.6 times (by weight) the amount of ethyl alcohol required for the food to be stored. However, since this adsorbent has a low bulk specific gravity, it has a drawback that the bulk of the food storage device becomes bulky. On the other hand, when an adsorbent having a large bulk specific gravity is used, the adsorbability is lowered and the amount of the adsorbent used is increased, which causes the disadvantage that the weight and the bulk of the entire food storage tool are increased. In addition, when filling a pouch with a powdery adsorbent and sealing the pouch, if the adsorbent adheres to the inside of the sealing part, so-called powder dust causes a sealing failure, or if the pouch is broken, it is powdery. There was a risk that the adsorbent of No. 1 would scatter and adhere to food.
Further, the powdery adsorbent is apt to be mistaken for food because it is easily mistaken for food, and it is harmless to the human body, but it is not preferable.

Further, as disclosed in, when liquid ethyl alcohol is enclosed in a film bag, there is a problem that the food storage device itself is ugly and difficult to handle, and the feel and the appearance are bad. In addition, when the film bag is poorly sealed or broken, there is a problem that ethyl alcohol flows out and adheres to food. Further, the work of packaging the liquid ethyl alcohol in a film bag is extremely difficult, and there is also a disadvantage that defective sealing is likely to occur. Even when using powder that is wet with ethyl alcohol, the food storage tool itself has a tingling sensation,
This is not preferable because there is a problem that ethyl alcohol flows out when the seal is defective or the bag is broken. Further, in the food preservation tool disclosed in, since the gelling agent for gelling ethyl alcohol needs to be about 0.2 times the amount of ethyl alcohol (weight ratio), downsizing of the food preservation tool, I was dissatisfied in terms of weight reduction.

The present invention has been made in view of these circumstances, and an object of the present invention is to effectively obtain the effect of maintaining the freshness of foods, to achieve downsizing and weight saving of food preservation tools, and to preserve foods. This is to reduce the risk of leakage or accidental ingestion of the contents of the tool.

[0007]

In order to solve the above problems, the invention according to claim 1 provides an N-vinylcarboxylic acid amide-based liquid absorbent containing a repeating unit represented by the following general formula (I) with ethyl acetate. A food preservation tool, characterized in that a freshness-retaining agent obtained by absorbing alcohol or an aqueous solution thereof is housed in a housing body made of a material at least part of which is permeable to ethyl alcohol gas.

Embedded image In the invention according to claim 2, the ratio of the ethyl alcohol or the aqueous solution thereof and the N-vinylcarboxylic acid amide-based liquid absorbent in the freshness-retaining agent is 1: 0.001 by weight.
The food storage device according to claim 1, wherein the food storage device has a ratio of 1: 0.1.
The invention according to claim 3 is the food preservation tool according to claim 1 or 2, wherein the freshness-retaining agent contains less than the same weight of water as ethyl alcohol. Claim 4
The described invention is a packaged food characterized in that the food and the food preservation tool according to any one of claims 1 to 3 are housed in a packaging material made of a material that is hardly permeable to ethyl alcohol gas. .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The concentration of the ethyl alcohol aqueous solution used in the present invention is
When the concentration of ethyl alcohol in the freshness-retaining agent is too low, the practical effect of maintaining freshness cannot be obtained because the rate of gasification of ethyl alcohol is slow. Therefore, the water contained in the freshness-retaining agent is preferably set in the range of less than the same weight as ethyl alcohol (anhydrous). From the viewpoint of the freshness preservation effect, it is preferable that the concentration of ethyl alcohol is high,
Anhydrous ethyl alcohol can also be used.

The N-vinylcarboxylic acid amide-based liquid absorbent used in the present invention contains a repeating unit represented by the following general formula (I), and is a homopolymer cross-linked product of N-vinylcarboxylic acid amide, or It is a copolymer cross-linked product with another monomer copolymerizable with N-vinylcarboxylic acid amide.

Embedded image

Examples of the N-vinylcarboxylic acid amide used in the present invention include N-vinylacetamide, N-methyl-N-vinylacetamide, N-vinylformamide,
Examples thereof include N-methyl-N-vinylformamide and N-vinylpyrrolidone. Among them, N-vinylacetamide, N-methyl-N-vinylacetamide, N-, which has a particularly high affinity with a highly concentrated ethyl alcohol aqueous solution. Vinylpyrrolidone is preferred.

Monomers copolymerizable with these N-vinylcarboxylic acid amides include (meth) acrylic acid (meaning acrylic acid or methacrylic acid; the same applies hereinafter) and its sodium, potassium, lithium, ammonium, etc. Of the above, alkyl esters such as methyl ester, ethyl ester, propyl ester, butyl ester, hydroxyalkyl esters such as hydroxyethyl ester, hydroxypropyl ester, etc., and lower alkylamino groups such as dimethylaminomethyl ester, dimethylaminoethyl ester, etc. A substituted alkyl ester, a lower alkyl ester substituted with a quaternary ammonium group such as a trimethylammonioethyl ester halide and a trimethylammoniopropyl ester halide thereof, and an amide thereof ( Amides substituted with alkylamino groups such as acrylamide, N-isopropyl- (meth) acrylamide, dimethylaminomethylamide, dimethylaminoethylamide, dimethylaminopropylamide, trimethylammonioethylamide halides, trimethylammonio Alkylamides substituted with quaternary ammonium groups such as propylamide halides, their sulfomethylamides, sulfoethylamides, linear or branched sulfopropylamides, sulfobutylamides and their sodium, potassium, lithium , Alkyl amides substituted with sulfonic acids or salts thereof such as ammonium salts, vinyl ethers such as (meth) acrylonitrile, methyl vinyl ether, ethyl vinyl ether, methyl vinyl ketone , Vinyl ketones such as ethyl vinyl ketone, lower vinyl carboxylates such as vinyl acetate and vinyl propionate, allyl sulfonic acid and its salts such as sodium, potassium, lithium and ammonium, maleic acid, fumaric acid, itaconic acid, and their Various salts such as salts of sodium, potassium, lithium, ammonium and the like, vinyl sulfonic acid and salts of sodium, potassium, lithium, ammonium and the like can be mentioned, but it is also possible to copolymerize a monomer other than those exemplified here, Of course it is possible.

Among these, in order to obtain an N-vinylcarboxylic acid amide-based liquid absorbent which is a relatively inexpensive and easily available monomer and which can highly absorb a high-concentration ethyl alcohol aqueous solution, ) Acrylic acid (salt) (meaning (meth) acrylic acid or a salt thereof, the same applies hereinafter), dimethylaminoethyl (meth) acrylate and a salt thereof, 2-
Particularly preferred are acrylamido-2-methylpropanesulfonic acid (salt), vinylsulfonic acid (salt), maleic acid (salt), itaconic acid (salt), and the like. Needless to say, two or more kinds of these monomers can be used at the same time. The ratio of the N-vinylcarboxylic acid amide and the monomer copolymerizable therewith is 1 by weight.
It is preferably 00:00 to 50:50, and if the ratio of the copolymerizable monomer is higher than this, the liquid absorbing ability for a high-concentration ethyl alcohol aqueous solution decreases, which is not preferable.

The N-vinylcarboxylic acid amide-based liquid absorbent used in the present invention must be crosslinked by an appropriate method. By being crosslinked, the N-vinylcarboxylic acid amide-based liquid absorbing agent is insolubilized and is kept in a non-flowing state after absorbing ethyl alcohol or its aqueous solution. Therefore, there is an advantage that the workability at the time of filling the container with the freshness-retaining agent that has absorbed ethyl alcohol or its aqueous solution is improved, and that the freshness-retaining agent is less likely to leak when the container is damaged. can get.

The cross-linking method can be carried out by copolymerizing the above-mentioned monomer (mixture thereof) with a compound having two or more polymerizable unsaturated groups in one molecule and / or N-vinylcarboxylic acid amide. The method of adding a compound capable of reacting with a functional group in the monomer of (1) to form a chemical bond (these are referred to as a cross-linking agent) and cross-linking together with the polymerization of the monomer, and a cross-linked precursor polymer which is not cross-linked There are various methods such as a method of manufacturing in advance and crosslinking this with the latter crosslinking agent, radiation, peroxide or the like. In order to manufacture at low cost and to manufacture a liquid absorbing agent suitable for use as a food freshness-retaining agent, a method of crosslinking with polymerization of a monomer is more preferable.

Examples of the cross-linking agent having two or more polymerizable unsaturated groups in one molecule are tetraallyloxyethane, pentaerythritol tetraallyl ether, pentaerythritol triallyl ether, pentaerythritol diallyl ether, trimethylolpropane triallyl. Ether, trimethylolpropane diallyl ether,
Polyallyl ether derived from compounds having two or more hydroxyl groups in one molecule, such as ethylene glycol diallyl ether, diethylene glycol diallyl ether, triethylene glycol diallyl ether, diallyl ether, monosaccharides, disaccharides, polysaccharides and cellulose, and pyro Tetraallyl melitate, triallyl trimellitate, triallyl citrate, diallyl oxalate, diallyl succinate, diallyl adipate, diallyl maleate, diallyl fumarate, diallyl terephthalate, diallyl isophthalate, diallyl phthalate, carboxyl in one molecule Compounds having two or more allyl groups in one molecule such as polyallyl ester derived from a compound having two or more groups, diallylamine, triallyl isocyanurate, and triallyl cyanurate 1 molecule of divinyl oxalate, divinyl malonate, divinyl succinate, divinyl glutarate, divinyl adipate, divinyl pimelic acid, divinyl maleate, vidinyl fumarate, trivinyl citrate, trivinyl trimellitate, tetravinyl pyromelliticate, etc. A compound having two or more vinyl ester structures therein, N, N'-butylenebis (N-vinylacetamide), N, N'-diacetyl-N, N'-divinyl-
Bis (N-vinylcarboxylic acid amide) compounds such as 1,3-bisaminomethylcyclohexane, N, N′-methylenebisacrylamide, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di ( Compounds having a plurality of acrylamide structures or (meth) acrylic groups, such as (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and pentaerythritol tri (meth) acrylate, divinylbenzene, di Any known cross-linking agent such as vinyl ether and allyl (meth) acrylate can be used. Further, one kind or two or more kinds of these cross-linking agents can be used.

As the cross-linking agent capable of reacting with the functional group in the other monomer to form a chemical bond, polyglycidyl ether, polyisocyanate, polyamine, polyol, depending on the functional group of the monomer, There are various ones such as polycarboxylic acid, and among them, particularly preferable one is polyglycidyl ether. Examples of the polyglycidyl ether used in the present invention include ethylene glycol diglycidyl ether, 1,1-bis (4-glycidyloxyphenyl) ethane, sorbitol polyglycidyl ether,
Sorbitan polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl Ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether,
Examples thereof include polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, and adipic acid diglycidyl ether, but other compounds can of course be used.

The cross-linking agent having two or more polymerizable unsaturated groups in one molecule and the cross-linking agent capable of reacting with a functional group in another monomer to form a chemical bond may be used alone or in combination. It is possible to use several kinds of cross-linking agents having two or more polymerizable unsaturated bonds in one molecule at the same time, or to react with functional groups in other monomers to form chemical bonds. It is also possible to use several kinds of the obtained crosslinking agents at the same time. The amount of these cross-linking agents used is usually 90: 10-99.
999: 0.001 and more preferably 9
The range is 5: 5 to 99.9: 0.1. If the amount of the crosslinking agent used is too much higher than the above range, the ability to absorb a high-concentration ethyl alcohol aqueous solution (absorbency) decreases,
It is economically unfavorable because the amount of the liquid absorbent added to ethyl alcohol or its aqueous solution increases. Further, if the amount of the cross-linking agent used is less than the above range, the liquid absorbing capacity (liquid absorbing capacity) of the liquid absorbing agent is improved, but the gel strength of the liquid absorbing agent obtained is excessively lowered, so that the fluidity after liquid absorption is increased. It becomes difficult to prevent leakage when the storage container for the freshness-retaining agent is damaged due to the occurrence of spillage. Or an uncrosslinked part occurs in the liquid absorbing agent and a part of it dissolves in ethyl alcohol or its aqueous solution,
Since the liquid absorbing agent in a state of absorbing the ethyl alcohol or the aqueous solution thereof has a spinnability, it is not preferable because a problem such as a defective sealing of the bag occurs when the container is filled.

The production (polymerization) process of the N-vinylcarboxylic acid amide liquid absorbing agent used in the present invention is not necessarily limited, but it is usually an aqueous solution polymerization method, a reverse phase suspension polymerization method, a reverse phase emulsion polymerization method. It is desirable to use the above method. For example, as an aqueous solution polymerization method, a monomer component and a cross-linking agent are uniformly dissolved in water or a mixed solvent of a hydrophilic organic solvent such as ethyl alcohol, tetrahydrofuran, or acetone that can be uniformly mixed with water, and vacuum desorption is performed. After dissolved oxygen in the system is removed by replacement with air or an inert gas such as nitrogen or carbon gas, a polymerization initiator is added to carry out copolymerization.
The polymerization initiation temperature is usually about -10 to 60 ° C, and the polymerization time is about 0.5 to 20 hours. When the photopolymerization process is adopted, the polymerization system may be irradiated with light using a light source such as a high pressure mercury lamp to carry out the polymerization.

As the above-mentioned polymerization initiator, a peroxide, an organic or inorganic peracid or a salt thereof, which can be uniformly dissolved in a polymerization solvent, or a redox type of an azobis compound alone or in combination with a reducing agent is used. As typical examples thereof, t-butyl peroxide, benzoyl peroxide, t-butyl hydroperoxide, benzoyl peroxide, azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane)
Dihydrochloride, 2,2'-azobis [2- (5-methyl-2
-Imidazolin-2-yl) propane] dihydrochloride, sodium persulfate, ammonium persulfate, hydrogen peroxide, combinations of persulfate with tertiary amines such as triethylamine and triethanolamine, and all known light sources. A polymerization initiator etc. are mentioned. The amount of the polymerization initiator used is
The amount is preferably 0.0001 to 5% by weight, and particularly preferably 0.001 to 1% by weight, based on all monomers. When the amount of the polymerization initiator used is more than 5% by weight, the molecular weight of the main chain of the crosslinked polymer does not increase and a polymer soluble in a solvent may be produced, which is not preferable. Also, 0.
When the amount is less than 0001% by weight, there is a problem that the reaction rate of the polymerization reaction does not increase and the amount of residual monomer increases.

The reaction product obtained by such polymerization is a gel containing the solvent used in the reaction, and is usually cut with a rotary cutter or the like, and if necessary, impurities are removed with a hydrophilic organic solvent or the like. Further, the solvent is removed by a method such as heating or depressurization and dried, and then, if necessary, pulverized and classified to obtain a powder having a particle size of several μm to 3 mm. It is also possible to use an aqueous solution having a predetermined ethyl alcohol concentration (or anhydrous ethyl alcohol may be used) as a polymerization solvent, perform only cutting after the polymerization, and use this as it is as the freshness-retaining agent in the present invention.

As the reverse phase suspension polymerization method and the reverse phase emulsion polymerization method, a monomer component and a cross-linking agent are uniformly dissolved in water and suspended or emulsified in an organic solvent which is not uniformly mixed with water. To cause a polymerization reaction. As the polymerization initiator, not only water-soluble ones but also those soluble in an organic solvent are used. Examples of the organic solvent that can be used include hydrocarbons such as hexane, cyclohexane, methylcyclohexane, heptane, octane, benzene, toluene, xylene, ethylbenzene, halogenated hydrocarbons such as carbon tetrachloride, dichloroethane, and mineral oil such as Isopar. Used. In the reverse phase suspension polymerization method and the reverse phase emulsion polymerization method, a surfactant is used as a dispersion stabilizer, and a protective colloid is used in combination as necessary. Typical examples of them are:
Examples thereof include various sorbitan fatty acid esters, various sucrose fatty acid esters, polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, and the like.

The method of removing dissolved oxygen in the system and the amount of the polymerization initiator used are the same as those described above. Further, in the case of the reverse phase suspension polymerization method, the polymer is usually obtained in the form of particles of several μm to several mm, so the polymer is filtered after the polymerization, and impurities are removed with a hydrophilic organic solvent or the like if necessary, It may be dried and, if necessary, pulverized. Further, water can be removed from the polymer by utilizing azeotropic distillation of hydrocarbon and water after the polymerization. In the case of reverse phase emulsion polymerization, the particle size of the polymer is usually about several μm or less, and the polymer is obtained as an emulsion with a hydrocarbon. This emulsion can be used as it is, or can be used after precipitating a polymer with an inorganic salt or acetone, filtering and drying. The polymerization reaction conditions are not particularly limited, but are generally as follows. The amount of the solvent used is the same as the aqueous solution of the monomer component to 20 times, preferably the same amount to 10 times, particularly preferably the same amount to 5 times, the polymerization initiation temperature is about -10 ° C to 90 ° C, and the reaction time is 0. .5 to 20
About an hour.

The N-vinylcarboxylic acid amide-based liquid absorbent used in the present invention is primarily obtained as a powder having a particle size of several μm or less to several mm, as described above. Upon contact, it absorbs ethyl alcohol or its aqueous solution and swells itself to form beads or dispersion, cream, paste-like viscous substance and the like. In addition, it is self-molded into a string shape, a film shape, a sheet shape, a plate shape, various molded products, and further combined with various base materials, various shapes,
It can be used in any form. The N-vinylcarboxylic acid amide-based liquid absorbent used in the present invention can highly absorb an aqueous solution containing a high concentration of ethyl alcohol. The liquid absorption ratio depends on the concentration of ethyl alcohol in the aqueous solution, the type of N-vinyldicarboxylic acid amide, the type and ratio of the monomer copolymerized with N-vinylcarboxylic acid amide, the type of crosslinking agent, and the addition amount. Although it cannot be generally stated because it changes, it is about 10 to 1000 times the weight of the subject. The term "absorption capacity" as used herein means, for example, 0.20 g of the absorbent is put into 1 liter of ethyl alcohol or an aqueous solution thereof to sufficiently absorb the liquid, and then absorbed by a box made of a 200-mesh wire mesh. It is calculated by the following formula after filtering the liquid absorbing agent that has been liquefied. Liquid absorption ratio = (weight of liquid absorbent absorbed / 0.20) -1.
0

For reference, various polymer water absorbing agents such as polyacrylate water absorbing agents and vinyl alcohol /
Acrylate copolymer water absorbent, modified vinyl alcohol water absorbent, sulfoalkyl methacrylate water absorbent,
Various products such as starch / acrylate graft type water absorbing agent and isobutylene / maleate type water absorbing agent are commercially available. These are used in the present invention, though low concentration ethyl alcohol-containing aqueous solution can absorb water relatively well. High-concentration ethyl alcohol aqueous solution as described above can only absorb a few times its own weight, or almost cannot absorb it, and it is practically used in consideration of economical efficiency and commercial value. You cannot do it.

The material permeable to ethyl alcohol gas used in the present invention (hereinafter referred to as “ethyl alcohol gas permeable material”) has an ethyl alcohol gas permeability of 20 g /
It is a material of m ² · 24 hr (50% RH · 40 ° C) or more. Here, the ethyl alcohol gas permeability in the present invention is indicated by the amount (g) of ethyl alcohol gas passing per 1 m ² of the material in an environment of a temperature of 40 ° C. and a relative humidity of 50% for 24 hours. And its value is 95
It is measured according to JIS Z-0208, which is generally used for measuring the amount of water vapor permeation through a resin film, using alcohol in pharmacopoeia.

Examples of such an ethyl alcohol gas permeable material include low density polyethylene (LDPE),
Polypropylene (PP), ethylene vinyl acetate copolymer (EVA), ethylene vinyl alcohol copolymer (EVAL), ionomer, nylon, various perforated films (eg polyethylene, polyethylene terephthalate (PET), etc.), or microporous A film-like material such as a film can be used. These film-shaped materials may be used as a single material or may be used as a composite material in which they are laminated. It is also possible to use a composite material obtained by laminating these film-like materials and breathable materials such as paper and non-woven fabric. These ethyl alcohol gas permeable materials may be subjected to water resistance treatment and oil resistance treatment as required.

In the present invention, the container used to store the freshness-retaining agent is at least partially made of the above ethyl alcohol gas permeable material, and can retain the freshness-retaining agent inside without leaking. Good. For example, one part of the housing is made of the above ethyl alcohol gas permeable material, and the other part has a permeability of 20 g / m ² · 24 hr (50%) for ethyl alcohol gas such as aluminum foil and PET.
RH / 40 ° C). A material that can be heat-sealed is preferably used. In this case, the container can be easily sealed after the freshness-retaining agent is housed in the container. The shape of the storage body may be arbitrary, and for example, it may be in the form of a pouch, or a form integrated with a packaging material for packaging food, a plastic tray, or the like.

The packaging material used to store the food and the food preservation tool in the present invention can suppress the permeation of ethyl alcohol gas so that the ethyl alcohol gas released from the food preservation tool does not escape from the packaging material. Anything will do. As the packaging material, a material hardly permeating ethyl alcohol gas is preferably used, and the packaging form can be arbitrary. Here, a material having a low permeability to ethyl alcohol gas means that the ethyl alcohol gas permeability is 10 g /
Material smaller than m ² · 24 hr (50% RH · 40 ° C), preferably ethyl alcohol gas permeability of 5 g / m
^{2 · 24hr (50% RH ·} 40 ℃) refers to the following materials. Examples of such a material impermeable to ethyl alcohol gas include a biaxially oriented polypropylene (OPP) film, a film obtained by laminating polyester and LDPE, a film obtained by laminating polyvinylidene chloride-coated polypropylene and LDPE, a poly film. Vinylidene chloride coated nylon and LDPE
Laminated film, biaxially stretched OPP and LDP
A film-shaped material such as a film obtained by laminating E and a film obtained by laminating biaxially stretched OPP and non-stretched polypropylene can be used.

The method for producing the food preservation tool of the present invention will be described below. The food preservation tool of the present invention is, for example, a powdery N-vinylcarboxylic acid amide-based liquid absorbent that absorbs ethyl alcohol or an aqueous solution thereof to prepare a freshness-retaining agent containing a predetermined concentration of ethyl alcohol. It is obtained by storing in a storage body. As a method of absorbing ethyl alcohol or its aqueous solution into the N-vinylcarboxylic acid amide-based liquid absorbent, there is a method of adding the N-vinylcarboxylic acid amide-based liquid absorbent to a predetermined concentration of ethyl alcohol or its aqueous solution and stirring. . Or,
Ethyl alcohol or an aqueous solution thereof having a concentration higher than the concentration of ethyl alcohol to be obtained, for example, 99.5% by weight
It is also possible to obtain a freshness-retaining agent containing a predetermined concentration of ethyl alcohol by preliminarily dispersing an N-vinylcarboxylic acid amide-based liquid absorbent in an aqueous solution of ethyl alcohol and adding water thereto.

According to the latter method, for example, 99.5% by weight of ethyl alcohol aqueous solution cannot be absorbed, but about 60% by weight of ethyl alcohol aqueous solution can highly absorb N.
It is preferable to use a vinylcarboxylic acid amide-based liquid absorbent because it is possible to prevent the generation of so-called “mamako”, which is a portion where the powder of the liquid absorbent is not uniformly dispersed and cannot be covered. Alternatively, instead of a 99.5% by weight ethyl alcohol aqueous solution, a polyhydric alcohol such as 1,3-butanediol or glycerin may be preliminarily moistened with the liquid absorbent, and ethyl alcohol or an aqueous solution thereof may be added thereto. It is possible to prevent the generation of "mamako". In addition, for example, ethyl alcohol or an aqueous solution thereof having a predetermined concentration is put in a bag-shaped container, and a powdery N-vinylcarboxylic acid amide-based liquid absorbent is added to the container,
The food storage device can also be manufactured by sealing the container.

Here, the amount of the N-vinylcarboxylic acid amide-based liquid absorbent added to the ethyl alcohol or its aqueous solution is determined by the liquid absorption ratio of the N-vinylcarboxylic acid amide-based liquid absorbent to the ethyl alcohol or its aqueous solution. . As described above, the N-vinylcarboxylic acid amide liquid absorbent used in the present invention has a liquid absorption capacity of 10
Since it is about 1000 times, it is used in a weight ratio of about 0.001 to 0.1, preferably about 0.002 to 0.05 with respect to 1 part of ethyl alcohol or its aqueous solution. The smaller the amount of the N-vinylcarboxylic acid amide-based liquid absorbent used, the more preferable it is in terms of downsizing and weight saving of the food storage tool, which is economically advantageous, but the amount of the N-vinylcarboxylic acid amide liquid absorbent is too small. If so, the wet state after liquid absorption and the suitability for filling deteriorate, so it is preferable to set an appropriate amount of use in consideration of these various requirements. Further, the amount of the freshness-retaining agent to be stored in the storage body is set in accordance with the concentration of ethyl alcohol or its aqueous solution, the water activity and the weight of the food to be stored, and the like. Furthermore, ethyl alcohol or an aqueous solution thereof and / or an N-vinylcarboxylic acid amide liquid absorbent,
If necessary, appropriate additives that are acceptable as food additives such as deodorants and edible flavors and pigments may be added. For example, ethyl alcohol or its aqueous solution and / or N-
It is effective to add a coloring agent having a color not like food to the vinylcarboxylic acid amide liquid absorbing agent to color the freshness-retaining agent so that it is not easily mistaken for food.

The packaged food of the present invention can be obtained by storing the food preservation tool of the present invention and the food in a packaging material. At this time,
It is necessary to arrange the food storage device and the food so that the food comes into contact with the ethyl alcohol gas diffused from the food storage device. For example, when packaging food items such as confectionery one by one (individual packaging) and performing double packaging in which a plurality of individually packaged food products are stored in one packaging material, an interior material used for individual packaging It is preferable that a material permeable to ethyl alcohol gas is used as the material and a material hardly permeable to ethyl alcohol gas is used as the exterior material used in double packaging.

The food preservation tool of the present invention can be applied to a wide range of packaged foods such as breads, confectionery, various processed foods, dried foods and grains, and the ethyl alcohol gas emitted from the food preservation tool comes into contact with the food. As a result, the effects of suppressing the growth of microorganisms such as mold, preventing food aging, and killing larvae and eggs adhering to grains and confectionery can be obtained. According to the food storage device of the present invention, since the N-vinylcarboxylic acid amide-based liquid absorbent has a large liquid absorbing ability, it is used to absorb a necessary amount of ethyl alcohol into the food to be stored. A small amount of N-vinylcarboxylic acid amide-based liquid absorbent is sufficient. Therefore, the weight saving of the food storage tool can be achieved. It is also possible to make the housing smaller, which reduces material costs.

The freshness-retaining agent in a state in which the N-vinylcarboxylic acid amide-based liquid absorbent has absorbed ethyl alcohol or its aqueous solution is a bead, dispersion, cream or paste-like viscous substance as described above. Therefore, it is not easily mistaken for food and there is less risk of accidental ingestion compared to conventional products. Further, unlike a conventional food storage tool using a powdery adsorbent, there is no risk of powder dust when the container is filled and sealed.
Further, compared with the conventional powdery adsorbent or a food storage tool using liquid ethyl alcohol, the content of ethyl alcohol or N-vinylcarboxylic acid amide liquid absorbent is leaked when the container is damaged. Hard to do. Furthermore, the freshness-retaining agent after the emission of ethyl alcohol is N
-Vinylcarboxylic acid amide-based liquid absorbent becomes a film and adheres to the inner surface of the container. Therefore, even if the consumer opens the container, it is already close to this state at that time, and the risk of erroneous eating is practically extremely small.

[0035]

【Example】

(Production Example A of N-vinylcarboxylic acid amide-based liquid absorbent) 3
In a bath maintained at 0 ° C, 250 g of N-vinylacetamide and 600 mg of tetraallyloxyethane were added to 745 g of deionized water in a 3-necked 1-liter separable flask equipped with a nitrogen introduction tube, a thermometer, and an exhaust tube. Dissolve,
Nitrogen was introduced into the system at 5 L / min for about 1 hour to degas. Then, 75 mg of 2,2'-azobis (2-amidinopropane) dihydrochloride dissolved in 5 ml of degassed water was added, and the mixture was allowed to stand for 12 hours in an adiabatic system. The obtained gel was cut with a mixer, washed with a 90% by weight aqueous acetone solution, and vacuum dried at 50 ° C. for 12 hours. Then, the mixture was pulverized and classified to obtain a liquid absorbing agent (referred to as liquid absorbing agent A) having a particle diameter of 200 to 500 μm. The liquid absorbing agent A was examined for liquid absorption ratios when various aqueous solutions of ethyl alcohol were absorbed. The results are shown in Table 1 below. The value of the liquid absorption ratio shows how many times the weight of the aqueous solution of ethyl alcohol absorbed.

(Production Example B of N-Vinylcarboxylic Acid Amide Absorbing Agent) In a bath kept at 30 ° C., in a three-necked 1 liter separable flask equipped with a nitrogen introduction tube, a thermometer, and an exhaust tube. 175 g of N-vinylacetamide, 2
263 g of 8.5% sodium acrylate aqueous solution, 300 mg of tetraallyloxyethane, 200 mg of N, N-methylenebisacrylamide were dissolved in 560 g of deionized water, and nitrogen was introduced into the system at 0.5 liter / minute for about 1 hour. And deaerated. Then, 75 mg of 2-2'-azobis (2-amidinopropane) dihydrochloride dissolved in 5 ml of degassed water was added, and the mixture was allowed to stand for 12 hours in an adiabatic system. The obtained gel was cut with a mincer, washed with an 80% by weight acetone aqueous solution, and vacuum dried at 50 ° C. for 12 hours. Then, the mixture was pulverized and classified to obtain a liquid absorbent having a particle diameter of 50 to 200 μm (hereinafter referred to as liquid absorbent B). The liquid absorption ratio of the obtained liquid absorbent B was examined in the same manner as the liquid absorbent A. The results are shown in Table 1 below.

Comparative Example 1 With respect to a commercially available polyacrylic acid type water absorbing agent, the liquid absorbing capacity was examined in the same manner as the liquid absorbing agent A. The results are shown in Table 1 below.

[0038]

[Table 1]

Example 1 A food storage tool was prepared using the above liquid absorbent A. First, the above-mentioned liquid absorbent A was added to an ethyl alcohol aqueous solution (hereinafter sometimes referred to as EtOH) having a concentration of 60% by weight to absorb the liquid, thereby preparing a freshness-retaining agent. On the other hand, EV with a weight per unit area of 27 g / m ²
The A film was folded in two and heat-sealed with one side left to produce a bag-shaped container having an inner size of 45 mm × 65 mm. The freshness-retaining agent was filled in the container, and the filled mouth was heat-sealed to obtain a food storage tool. Twenty such food storage tools were produced. The average total weight of this food storage device was 1.05 g.

Further, in order to test the bacteriostatic effect, a sample inoculated in a water activity adjusted medium was prepared. The medium contains 3.9 g of potato dextrose, 75 g of sucrose and 100 g of water.
Was used and the pH was adjusted with an aqueous NaOH solution. The water activity of this medium was 0.90 as measured by a water activity meter (FWA-200 manufactured by Freund). The bacterial solution was prepared by dissolving 1 platinum loop of Penicillium notatum, which had been separated, in 50 ml of sterilized physiological saline, and diluting 1 ml of this solution with 200 ml of sterilized physiological saline. To prepare a sample, first, 1 ml of the above-mentioned bacterial solution was put into a sterilized petri dish (95 mm in diameter, 20 mm in depth; manufactured by Eiken Kikai Co., Ltd.), and then about 50 g of the above-mentioned medium was poured into this petri dish. Then, after mixing the bacterial solution and the medium in a petri dish, the mixture was allowed to stand for 2 hours to obtain a sample.

As shown in FIG. 1, an inner size of 155 mm × 21 made of a film obtained by laminating a KOP film (polyvinylidene chloride-coated polypropylene) and an LLDPE film (linear low-density polyethylene).
In a 0 mm packaging bag (indicated by 2 in the figure), one food preservation tool (indicated by 1 in the figure) obtained above and a sample (3 in the figure)
1) was heat-sealed. Subsequently, this packaging bag 2 was left in a constant temperature bath at 25 ° C., and the ethyl alcohol gas concentration in the packaging bag 2 was measured on the first and fifth days after the standing. The results are shown in Table 2 below.

The ethyl alcohol gas was measured by gas chromatography. The measurement conditions were as follows. Measuring device Model: GC-14A (FID) (manufactured by Shimadzu Corporation) Filler: PEG-20M 10% carrier: Chromosorb WAW DMCS column: SUS 2m × 3 mm carrier ^{_{gas: N 2 1.4kg / cm 2 H}} 2 1. 0 kg / cm ² air 1.0 kg / cm ² Temperature of sample injection part and detection part: 150 ° C Column temperature: 80 ° C

When the sample 3 in the packaging bag 2 was observed on the 5th and 10th days after the standing, no mold growth was observed at all. Furthermore, the concentration of ethyl alcohol gas in the packaging bag 2 is no longer increased.
When the container of the food storage device 1 was opened and observed on the day, it was found that the liquid absorbent A adhered to the inner surface of the container in the form of a film.

Example 2 A food preservation tool was prepared in the same manner as in Example 1 except that the amount of the 60% ethyl alcohol aqueous solution absorbed by the liquid absorbent A was increased. The amount of the ethyl alcohol aqueous solution was 1. The weight of the ethyl alcohol aqueous solution held in the food storage device of Example 1 was 1.
When set to 0, it was set to 1.5 in this embodiment. Twenty such food storage tools were produced. The total weight of this food storage device was 1.58 g on average. The food preservation tool 1 obtained as shown in FIG. 1 was put in a packaging bag 2 together with the sample 3 in the same manner as in Example 1 above. The results of examining the concentration of ethyl alcohol gas in the packaging bag 2 are shown in Table 2 below. Also,
Sample 3 in packaging bag 2 on the 5th and 10th days after leaving
As a result, no mold growth was observed at all.

Comparative Example 2 A food storage tool was prepared in the same manner as in Example 1 except that silicon dioxide fine powder used in a commercial food storage tool was used in place of the liquid absorbent A. Since the silicon dioxide fine powder used here has a lower ability to retain ethyl alcohol as compared with the liquid absorbent A, in order to hold the same amount of the ethyl alcohol aqueous solution as in the above Example 1, the liquid absorbent A of the above Example 1 was used. About 0.5 g was needed more than the amount used. Twenty such food storage tools were produced. The total weight of this food storage device was 1.56 g on average. The food preservation tool 1 obtained as shown in FIG. 1 was placed in a packaging bag 2 together with the sample 3 in the same manner as in Example 1 above, and the ethyl alcohol gas concentration in the packaging bag 2 was examined. The results are shown in Table 2 below. Also,
Sample 3 in packaging bag 2 on the 5th and 10th days after leaving
As a result, it was observed that mold growth was slightly observed on the 10th day after standing.

[0046]

[Table 2]

From the results shown in Table 2, the food preserving tool of Example 1 is lighter than that of Comparative Example 2 in spite of holding the same amount of the ethyl alcohol aqueous solution, and can be put into the packaging bag. It is recognized that the emission speed of the ethyl alcohol gas is equal to or higher than that of Comparative Example 2. In addition, the food storage device of Example 2 has a total weight almost the same as that of Comparative Example 2, but holds 1.5 times as much ethyl alcohol aqueous solution as that of Comparative Example 2, and ethyl that diffuses into the packaging bag. It is recognized that the amount of alcohol gas is also large. Further, comparing the mold growth conditions in Sample 3, it can be seen that the food preserving tools of Example 1 and Example 2 exhibited a better bacteriostatic effect than that of Comparative Example 2.

Example 3 A food preservation tool was produced in the same manner as in Example 1 except that the container for accommodating the freshness-retaining agent was made smaller. That is, as in Example 1 above, a 60 wt% aqueous solution of ethyl alcohol and liquid absorbent A were used.
Was used to prepare a freshness-retaining agent. This freshness-retaining agent is made of EVA film of the same material as in Example 1 and has an inner dimension of 25 mm.
It was filled in a bag-shaped storage body of × 35 mm, and the filled mouth was heat-sealed to obtain a food storage tool. Twenty such food storage tools were produced. The total weight of this food storage device was 1.05 g on average as in Example 1 above.

As shown in FIG. 1, the obtained food storage tool 1 was packed together with the sample 3 in the same manner as in the above-mentioned Example 1, and the packaging bag 2 was used.
Stored inside. The packaging bag 2 was allowed to stand in a thermostat at 25 ° C., and the ethyl alcohol gas concentration in the packaging bag 2 was measured in the same manner as in Example 1 on the 1, 5, 10, 15, 20 days after the standing. The results are shown in Table 3 below. FIG. 2 is a graph showing the result. Also, after leaving for 5,1
On days 0, 15, and 20, the mold growth state and the average diameter of colonies in Sample 3 in the packaging bag 2 were visually observed. The results are shown in Table 4 below. In Table 4, the mold growth conditions are as follows:-, +, ++, ++
It is expressed in 4 steps using +. − Indicates no mold growth at all, + indicates slight mold growth, ++ indicates advanced mold growth, ++ indicates
The molds that have progressed considerably are shown below.

(Example 4) The same as Example 3 except that the amount of the 60% ethyl alcohol aqueous solution absorbed in the liquid absorbent A was increased and the container for storing the freshness-retaining agent was slightly enlarged. To produce a food storage tool. That is, in the same manner as in Example 3 above, a freshness-retaining agent was prepared using a 60% by weight aqueous solution of ethyl alcohol and the liquid absorbent A. The amount of the ethyl alcohol aqueous solution was set to 1.5 in this example when the weight of the ethyl alcohol aqueous solution held in the food storage device of Example 3 was 1.0. This freshness-retaining agent was filled in a bag-shaped container made of EVA film of the same material as in Example 3. The size of the bag-shaped container was slightly larger than that of Example 3 and had an inner size of 25 mm × 40 mm.
The mouth of the filled bag-shaped container was heat-sealed to obtain a food storage tool. Twenty such food storage tools were produced. The total weight of this food storage device was 1.58 g on average as in Example 2 above.

In the same manner as in Example 3 above, the obtained food preservation tool 1 was put together with the sample 3 in the packaging bag 2, and the ethyl alcohol gas concentration in the packaging bag 2 was measured. The results are shown in Table 3 below and FIG. Further, in the same manner as in Example 3 above, the mold growth state and the average diameter of colonies in Sample 3 in the packaging bag 2 were visually observed.
The results are shown in Table 4 below.

(Comparative Example 3) As a comparative example for confirming the bacteriostatic effect, a packaging bag 2 similar to that in Example 3 was prepared in which only the sample 3 was stored without the food storage tool. Then, in the same manner as in Example 3 above, the mold growth state and the average diameter of colonies in Sample 3 in the packaging bag 2 were visually observed. The results are shown in Table 4 below.

The results of measuring the concentration of ethyl alcohol gas in the packaging bag 2 and the mold growth state and the average diameter of colonies of the sample 3 in the packaging bag 2 of the food preservation tool of Comparative Example 2 were visually observed. The observation results are also shown in Tables 3 and 4 below and FIG.

[0054]

[Table 3]

[0055]

[Table 4]

From the results shown in Tables 3 and 4 and FIG. 2, the food preserving tool of Example 3 is lighter and smaller than the food preserving tool of Comparative Example 2 and can be stored in a packaging bag. Although the emission speed of ethyl alcohol gas is slightly inferior to that of Comparative Example 2, it is recognized that the bacteriostatic effect is almost the same as that of Comparative Example 2. The total weight of the food preservation tool of Example 4 in which the amount of the ethyl alcohol aqueous solution was 1.5 times that of Comparative Example 2 was almost the same as that of Comparative Example 2, but the size of the container was larger than that of Comparative Example 2. It is small. And, the emission speed of ethyl alcohol gas into the packaging bag is almost equal to that of Comparative Example 2, the peak of ethyl alcohol gas concentration in the packaging bag is higher than that of Comparative Example 2, and the bacteriostatic effect is more than that of Comparative Example 2. Is also found to be excellent.

[0057]

As described above, according to the food storage device of the present invention, the ethyl alcohol retained by the N-vinylcarboxylic acid amide-based liquid absorbent is vaporized inside the container, and the ethyl alcohol gas is stored. Dispersed outside the body. Therefore, by contacting the food with the ethyl alcohol gas emitted from this food storage tool, suppression of the growth of microorganisms such as mold, prevention of food aging,
It is possible to obtain advantageous effects for maintaining the freshness of foods, such as killing larvae and eggs attached to grains and confectionery. Further, since an N-vinylcarboxylic acid amide-based liquid absorbent having a large liquid absorption capacity is used as the liquid absorbent, N-vinylcarboxylic acid amide-based liquid absorbent is used to absorb the required amount of ethyl alcohol for the food to be stored.
A small amount of vinylcarboxylic acid amide-based liquid absorbent can be used. Therefore, it is possible to reduce the weight of the food storage tool and the size of the container, and it is possible to reduce the material cost.

Furthermore, the N-vinylcarboxylic acid amide-based liquid absorbent used in the food storage device of the present invention is ethyl alcohol or a bead-shaped dispersion liquid when absorbing it,
Since it becomes a cream or pasty viscous substance, it is not easily mistaken for food and there is little risk of accidental ingestion. Further, since the freshness-retaining agent is difficult to flow, there is little risk that the freshness-retaining agent will leak and adhere to foods should the container be damaged. Furthermore, the freshness-retaining agent after the release of ethyl alcohol is in a state in which the N-vinylcarboxylic acid amide-based liquid absorbent is in the form of a film and adheres to the inner surface of the container, so it is not easily mistaken for food and food preservation The risk of accidental ingestion after using the tool is extremely low.

Further, according to the packaged food of the present invention, since the food and the above-mentioned food preservation tool are housed in the packaging material made of a material that is hardly permeable to ethyl alcohol gas, ethyl alcohol released from the food preservation tool is used. Sure the gas,
In addition, the food can be efficiently contacted. Therefore, an effective food freshness retention effect can be obtained with a simple configuration in which the food preservation tool is stored in the packaging material of the packaged food.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an experimental example for testing the effect of the food storage device of the present invention.

FIG. 2 is a graph showing the measurement results of the concentration of ethyl alcohol gas in the packaging bags obtained in Examples and Comparative Examples.

[Explanation of symbols]

 1 Food storage tools 2 Packaging bags 3 Samples

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jiro Mohino 2-14-2 Takadanobaba, Shinjuku-ku, Tokyo Within Freund Sangyo Co., Ltd. (72) Inventor Akoji Matsuo 2-14 Takadanobaba, Shinjuku-ku, Tokyo No. 2 inside Freund Sangyo Co., Ltd. (72) Inventor Junichi Narita 2-14-2 Takadanobaba, Shinjuku-ku, Tokyo Inside Freund Sangyo Co., Ltd.

Claims (4)

[Claims] 1. A freshness-retaining agent obtained by absorbing ethyl alcohol or an aqueous solution thereof into an N-vinylcarboxylic acid amide-based liquid absorbent containing a repeating unit represented by the following general formula (I), at least in part. A food storage tool, characterized by being housed in a housing body made of a material permeable to ethyl alcohol gas. Embedded image 2. The weight ratio of ethyl alcohol or an aqueous solution thereof to the N-vinylcarboxylic acid amide-based liquid absorbent in the freshness-retaining agent is 1: 0.001 to 1: 0.1.
The food preservation tool according to claim 1, wherein 3. The freshness-retaining agent contains less than the same weight of water as ethyl alcohol.
Alternatively, the food preservation tool according to item 2. 4. A packaged food, characterized in that the food and the food preservation tool according to any one of claims 1 to 3 are housed in a packaging material made of a material that is impermeable to ethyl alcohol gas.