JP3528873B2 - Food package for microwave cooking and packaging method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a food package for microwave oven cooking and a packaging method therefor. More specifically, a sheet-shaped oxygen scavenger is enclosed in the package for excellent quality retention, and
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a food package for microwave oven cooking, which is provided for heating and cooking by a microwave oven with the deoxidizer attached, and a packaging method thereof. The microwave food packaging of the present invention,
As food, processed rice and barley foods such as sterile cooked rice, fried foods, steamed foods, various prepared foods, raw delicacies, Japanese and Western confectionery, various noodles, baked potatoes, semi-cooked foods such as retort foods, cooked foods, etc.
It is used to maintain the quality of various foods that are cooked in a microwave oven.

[0002]

2. Description of the Related Art In recent years, as one of food preservation techniques, a preservation technique using an oxygen scavenger has been established, and its application range to a wide variety of foods is expanding. Oxygen scavenger storage technology encloses the oxygen scavenger in the food packaging container and absorbs and removes oxygen in the container to keep it in an anaerobic state, thereby preventing oxidation of oil and fat in foods, fading prevention, and flavor retention. It prevents insect damage, prevents aerobic bacteria from breeding, and maintains good food quality.
On the other hand, with the widespread use of household microwave ovens, it is becoming common to heat and cook or thaw the packaged food by irradiating it with microwaves while packaging it. Therefore, recently, various types of packaged foods that have been pre-cooked for microwave oven cooking are sold by food manufacturers.
Furthermore, in food manufacturing manufacturers, not only simply thawing foods at home, but for the purpose of inventory adjustment and production adjustment due to fluctuations in demand, the packaged foods produced are frozen and thawed by microwave irradiation. There are also things like shipping. In this way, the cooking technique for cooking food by microwave oven (microwave irradiation) is diversifying and expanding.

With the spread of foods for cooking and heating in microwave ovens, it is desired to improve the preservability thereof, and the application of oxygen scavengers to packaged foods for cooking and heating in microwave ovens is becoming more and more important. In this case, the packed food for microwave heating cooking does not need to remove the enclosed oxygen scavenger from the packing container one by one during cooking,
It is desirable that the food package can be microwaved as it is. By the way, a commonly used oxygen scavenger is a granular oxygen scavenger composition containing iron powder as a main agent, packaged in a small bag of a breathable packaging material. However, when the conventional oxygen scavenger in a pouch is irradiated with microwaves, most of the microwaves penetrate the packaging material and are absorbed by the oxygen scavenger composition of the iron powder main component, and as a result, the oxygen scavenger is removed. An eddy current is generated in the composition and heat is rapidly generated. Therefore, the packaging material is burnt out, or the water contained in the oxygen absorber composition is rapidly vaporized and expanded, the sachet is broken and the oxygen absorber is discharged, and the food and the like are contaminated. There was a problem that happened. Further, it has been conventionally pointed out that the pouch-shaped oxygen scavenger has problems such as loadability in a food package and a feeling of foreign matter.

Various proposals have been made to date for the problem of the microwave resistance of the iron powder type oxygen scavenger as described above. For example, in the method of Japanese Patent Laid-Open No. 63-55075, a metal foil or the like is used as a packaging material for an oxygen scavenger for a microwave oven, and the contents are prevented from generating heat. However, in the case of this method, an eddy current is generated in the metal foil of the oxygen absorber package by microwave irradiation, and sparks sometimes occur from the end of the oxygen absorber package. Further, Japanese Patent Laid-Open No. 2-413 proposes a deoxidizer for a microwave oven using a deoxidizer composition in which iron powder and a specific filler are mixed. However, the oxygen scavenger of this proposal aims to improve the microwave resistance by diluting the iron powder with a filler so as not to generate an eddy current. However, there is a problem that stains, powdery debris, etc. are likely to occur during filling and packaging, and in particular, when the oxygen scavenger is stored for a long period of time, it solidifies and the microwave resistance decreases. As mentioned above,
Conventional food packages for microwave ovens using oxygen scavengers are not always satisfactory, and there are many points to be improved.

[0005]

DISCLOSURE OF THE INVENTION The object of the present invention is to provide excellent quality retention by an oxygen scavenger, to be microwave-irradiated without any problem, and to be safe and hygienic. Another object of the present invention is to provide a novel food package for microwave cooking, which is excellent in the production thereof, is easy to manufacture, and does not give a feeling of foreign matter to the enclosed oxygen scavenger unlike conventional oxygen scavengers.

[0006]

The inventors of the present invention have conducted extensive studies in view of the problems of the prior art, and as a result, kneaded and dispersed an iron powder type oxygen absorber with a thermoplastic resin to form a sheet. The present inventors have completed the present invention by discovering that a deoxidized sheet has extremely excellent microwave resistance. That is, the microwave-cooked food package and its packaging method of the present invention are a sheet-shaped oxygen scavenger comprising a food obtained by kneading an iron-based oxygen scavenger composition with a thermoplastic resin to form a sheet. At the same time, it is characterized in that it is hermetically sealed in a gas barrier container.
Here, what is obtained by kneading the iron-based oxygen scavenger composition with a thermoplastic resin and forming a sheet is referred to as a deoxidation sheet, and at least a part or all of the deoxidation sheet is a breathable packaging material. The coated product is called a sheet-shaped oxygen absorber. However, in the following, the deoxidizing sheet and the sheet-like oxygen scavenger may be collectively referred to as a sheet-like oxygen scavenger.

As the sheet-shaped oxygen scavenger in the present invention, an iron-based oxygen scavenger is kneaded and dispersed with a thermoplastic resin to form a sheet.
The deoxidized sheet obtained by subjecting this sheet to a stretching treatment after stretching is excellent in microwave resistance and oxygen absorbing ability and is preferably used.

The iron powder-based oxygen scavenger used in the deoxidizing sheet contains iron powder as a main component and a metal halide salt, and if necessary, components such as activated carbon and a poorly water-soluble filler can be added. The iron powder-based oxygen scavenger may be a mere mixture of the above components, but is preferably a mixture of iron powder or a mixture of iron powder and activated carbon coated with a metal halide salt or in which a metal halide salt is dispersed and adhered.

As the iron powder, for example, reduced iron powder, electrolytic iron powder, atomized iron powder and the like are used, and it is preferable that the particle size is fine, usually the particle size is 100 μm or less, preferably 50 μm.
The following are used: Examples of the metal halide include sodium chloride, potassium chloride, barium chloride,
Calcium chloride, magnesium chloride, etc. are used.

As the thermoplastic resin in which the iron-based oxygen scavenger is dispersed, olefin resins such as low density polyethylene, high density polyethylene, polypropylene, ethylene-α-olefin copolymer and polymethylpentene are used.

A deoxidizing sheet is disclosed in, for example, Japanese Patent Laid-Open No. 2-728.
It can be easily produced by the method described in 51.
An iron powder type oxygen scavenger is kneaded at a ratio of 30 to 85% by weight with respect to 15 to 75% by weight of the above-mentioned thermoplastic resin, melted to form a sheet, and stretched. The draw ratio is preferably 1.5 to 10 times. The thickness of the deoxidizing sheet is preferably in the range of 0.2 to 3 mm, and is appropriately selected in consideration of the required oxygen absorption performance, workability, loadability and the like.

In the present invention, the deoxidizing sheet is used as a sheet-shaped deoxidizing agent in which at least a part or the whole is covered with a breathable packaging material. The sheet-shaped oxygen scavenger is roughly classified into two forms: one in which a breathable wrapping material is used to wrap the deoxidizing sheet, and one in which the breathable wrapping material and the deoxidizing sheet are laminated and covered. It is divided into two. Specific examples of the sheet-shaped oxygen scavenger include those of the following forms. However, the present invention is not limited to these. 1) A form in which a deoxidizing sheet is wrapped in a breathable packaging material. Polyethylene terephthalate / polyethylene on one side and water resistant non-woven fabric on the other side ("Tyvek" made by DuPont, "Luxer" made by Asahi Kasei, etc.), and a deoxidizing sheet was sandwiched between two packaging materials, Heat-sealed form. 2) A label type configuration in which a deoxidizing sheet, a breathable packaging material, and an adhesive material are combined. For example, a label type form in which a base layer having an adhesive layer / a deoxidizing sheet / a breathable layer are laminated in this order, and the breathable layer is directly adhered to the base layer at the peripheral portion,
Breathable adhesive layer / breathable packaging material layer / deoxidizing sheet / adhesive layer /
A label type form integrated with display labels laminated in order of display label layers. 3) A mount form in which a deoxidizing sheet is laminated or packaged with a breathable packaging material.

As the breathable packaging material, a packaging material for a conventional oxygen absorber packaging can be used. For example, a packaging material in which a perforated film is laminated on paper, a water-resistant non-woven fabric (“Tyvek” manufactured by DuPont, “Luxer” manufactured by Asahi Kasei, etc.), various microporous membranes (“Duragard” Cellanize, “NF”). Sheet "manufactured by Soda Tokuyama," Nitoflon "manufactured by Nitto Denko, etc.), and the above water-resistant non-woven fabric, a packaging material in which a perforated film is laminated on a microporous membrane, and the like, which are further water-resistant and oil-resistant treated. Can also be used. Microwave cooked foods are usually foods with a high water content and oily foods, and the sheet-shaped oxygen scavenger packaging material is preferably liquid-resistant, and in order to prevent elution of iron rust, etc., The non-woven fabric, microporous membrane, and other water- and oil-resistant air-permeable packaging materials laminated with a heat-resistant film such as perforated polyethylene terephthalate, polyamide, eval, and aluminum foil are preferred. For example, a polyethylene terephthalate / polyethylene perforated film, a nylon / polyethylene perforated film, etc. and a water-resistant non-woven fabric, a microporous membrane, a water- and oil-resistant wrapping material laminated, and further a perforated polyolefin on the other surface. Examples include a three-layered packaging material in which a resin film is laminated.

In the present invention, the sheet-shaped oxygen scavenger is usually
A water-dependent type is used, which absorbs oxygen by utilizing water evaporated from food. When the target food has a low water content, it can be used as a self-reactive type by combining a water-absorbent resin and a sheet that retain water. Further, depending on the purpose, it is possible to appropriately use a deodorizing sheet, a water-absorbent resin, a water-absorbent sheet, a carbon dioxide gas absorbing sheet, etc., which is exemplified by paper carrying activated carbon or the like. .

The sheet-shaped oxygen scavenger is sealed with the food in a barrier container to form a food package. At the time of encapsulation, the sheet-shaped oxygen absorber is fixed depending on the purpose, but in some cases, it is merely encapsulated. An adhesive, hot melt, double-sided tape, or the like can be used for immobilization, and the sheet-shaped oxygen scavenger of the above-mentioned form is appropriately selected depending on the method.

The barrier container for accommodating the food is at least an oxygen barrier property, and can be cooked by passing microwaves through a microwave oven. The form may be a bag or a container. The barrier property container preferably has an oxygen permeability of 100 ml / m ² · 24 Hr · atm or less as barrier performance.

As the barrier-type container, various oxygen-barrier-type packaging bags and containers generally used for storing oxygen absorbers in foods can be used. There is a bag of a barrier plastic film as a packaging bag, for example, polyethylene terephthalate, polyamides, polyvinylidene chloride, ethylene vinyl alcohol copolymer, polyvinyl alcohol, polyvinylidene chloride coat film, aluminum vapor deposition film, Aluminum foil, silica evaporated film, other films, and the above films and polyethylene, EVA,
A bag made of ionomer, EAA, EMMA, EEA, a composite film in which other polyolefin-based resin films are laminated, a triple nylon (manufactured by Ozaki Light Chemical Co., Ltd.), a barrierlon (manufactured by Asahi Kasei), and various other coextruded films is preferably used. . A bag such as a barrier shrink film can also be used. As the barrier container, a container made of polypropylene / ethylene vinyl alcohol copolymer / polypropylene or the like and top-sealed with the barrier film can be used.

An example of a packaging mode of a package in which a sheet-shaped oxygen absorber is enclosed in a food in a barrier container will be described with reference to the drawings. The package of FIG. 1 is a sheet of sheet-shaped oxygen scavenger and food is put in a packaging bag of a barrier film and heat-sealed. The packaging body of FIG. 2 is a packaging container in which a barrier plastic tray containing food is top-sealed with a lid having a label-type sheet-shaped oxygen absorber attached. The package shown in FIG. 3 is obtained by placing food in a container in which a breathable surface of a sheet-shaped oxygen scavenger is applied to the ventilation holes and adhering it, and then placing the food in a packaging bag of a barrier film and heat-sealing it. is there. The food package sealed and stored in a barrier container can be cooked in a microwave oven as it is without opening a sheet-like oxygen scavenger without breaking the airtightness of the container.

Foods packaged in the package of the present invention include various foods that are cooked in a microwave oven, such as semi-cooked foods and cooked foods. For example, processed rice and barley foods such as red rice, tea rice, cooked rice, and mixed rice, hamburger.
Deep-fried foods such as gu, nuggets, croquettes, bite cutlets, American dogs, various fried foods, fish grilled foods, steamed foods, wrapped foods, steamed foods such as gyoza, shumai, etc., boiled beans, eggs and eggs. , Side dishes such as simmered food, fried food, stir-fried vegetables, dried squid overnight,
Raw delicacies typified by wiener grilled, edamame, yaktori,
Japanese and Western confectionery represented by pie confectionery, dorayaki, bun, etc. and various noodles exemplified by yam, yakisoba, yaki udon, spaghetti, etc., retort foods represented by curry, stew, etc., microwave Examples include foods that can be effectively heated and cooked by irradiation. In particular, precooked foods such as prepared foods, raw delicacies, and deep-fried foods are often cooked at home by a microwave oven and served on a table, and can be effectively used as a microwave food package according to the present invention. .

[0020]

EXAMPLES Next, examples will be described. The present invention is not limited to this embodiment.

Example 1 100 parts of an iron-based oxygen scavenger having an average particle size of 70 μm and 150 parts of polyethylene were mixed, heated and melted at 190 ° C., and formed into a sheet by an extruder, and then this sheet was formed. Was stretched 4 times in the longitudinal direction at 50 ° C. to prepare a high-performance deoxidized sheet with a thickness of 1 mm. The prepared deoxidizing sheet was punched into a circle having a diameter of 60 mmφ. Also, stretched nylon (thickness 15 μm)
/ Polyethylene (thickness 15μm) 0.8m diameter on film
A breathable sheet obtained by heat-laminating a perforated film having a pore size of 7 m with an opening ratio of 7% and a water-resistant nonwoven fabric Luxer (manufactured by Asahi Kasei) was punched into a circle of 70 mmφ. Two circular breathable sheets are stacked with the surfaces of the luxers facing inward, and the circular deoxidizing sheet is sandwiched between the sheets to heat seal the peripheral edge of the sheet. I got an agent. Place the baked rice ball on the sheet-shaped oxygen absorber obtained above, store it in a vinylidene chloride nylon / polyethylene film barrier packaging bag, and heat seal the bag mouth to make a baked rice ball. A package was prepared and stored at a temperature of 10 ° C for 14 days. The baked rice ball package, which had been stored for 14 days, was subjected to microwave irradiation for 2 minutes in a household 500W microwave oven (Mitsubishi Electric RR-50) while leaving small holes in the bag, and after being subjected to heating and cooking, the appearance was observed and A sensory evaluation was performed. The results are shown in Table 1.

Example 2 The deoxidizing sheet having a thickness of 1 mm prepared in Example 1 was used for 30 m.
A circular deoxidizing sheet was punched into a circle of mφ and prepared. A water- and oil-resistant paper is heat-laminated with a perforated polyethylene film to obtain a breathable packaging material, and a white polypropylene film (thickness 35 μm) is coated on one side with a synthetic rubber elastomer-based adhesive to form an adhesive layer. Then, a silicone coated paper, which is a release paper, was attached to this surface, and then the same adhesive was applied to the other surface of the polypropylene film to prepare a pressure sensitive adhesive sheet with a separator layer. Next, the circular deoxidizing sheet was placed on the adhesive surface side of the adhesive sheet, and a breathable packaging material was placed on the adhesive sheet, and the deoxidizing sheet was covered and pressure-bonded to the circular deoxidizing sheet. The air-permeable packaging material and the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet were adhered to each other at the peripheral portion of. Finally, a circular sheet-shaped oxygen scavenger was punched out with a punch to a diameter of 50 mm to obtain a label sheet-shaped oxygen scavenger. Next, the roasted rice balls were placed in the same barrier packaging bag as in Example 1, the separator layer of the label type sheet-shaped oxygen absorber was peeled off from the inside of the bag and fixed by adhesion, and then the bag mouth was opened. Was heat-sealed to prepare a baked rice ball package. Put this baked rice ball package at 10 ℃ for 14
After storing for one day, the same test as in Example 1 was performed. The test results are shown in Table 1.

Example 3 The deoxidized sheet (thickness 1 mm) prepared in Example 1 was attached to one side of a water resistant nonwoven fabric ("Tyvek") with a highly breathable adhesive sheet (manufactured by Nitto Denko Corporation). Adhesion via a double-sided adhesive tape with a release paper (width 10 m
m) was adhered at 40 mm intervals. 60 x 50
With a mm □ cutting die, double-sided tape is placed on both ends to make a square shape and deoxidized sheet agent / breathable adhesive sheet / Tyvek / double-sided adhesive tape (both ends) Configuration chart
Got On the deoxidized sheet surface of the obtained sheet, a product label (60 × 50 mm □) consisting of display paper / adhesive with information such as product name and bar code is adhered to display the function. A label type sheet-shaped oxygen scavenger having Next, a polypropylene lidded container with a 40 × 40 mm □ opening on the lid (length 120 mm, width 100 mm, depth 3
(5 mm) containing the baked rice balls and covering the lid, the label-type sheet-shaped oxygen scavenger is peeled off from the release paper at both ends, and the adhesive surface is exposed. It was fixed by adhesion so as to cover. Further, this container containing the baked rice balls was stored in a barrier bag (15 × 18 cm) made of the same material as used in Example 1, and the bag mouth was heat-sealed to form a baked rice ball package. Created. This baked rice ball package was stored at a temperature of 10 ° C. for 14 days and then subjected to the same test as in Example 1. The test results are shown in Table 1.

Comparative Example 1 Instead of the sheet-shaped oxygen scavenger, a commercially available oxygen scavenger in which a granular oxygen scavenger containing iron powder as a main agent was put in a small bag (oxygen absorption amount 100 ml
And a size of 50 × 50 mm) were used, and a baked rice ball package was prepared in exactly the same manner as in Example 1.
This baked rice ball package was stored at a temperature of 10 ° C. for 14 days and then subjected to the same test as in Example 1. The test results are shown in Table 1.

Comparative Example 2 A baked rice ball package was prepared in the same manner as in Example 1 except that the oxygen absorber was not used. This baked rice ball package was stored at a temperature of 10 ° C. for 14 days and then subjected to the same test as in Example 1. The test results are shown in Table 1.

[0026]

[Table 1]

[0027]

Industrial Applicability The food package for microwave cooking according to the present invention is enclosed with a sheet-shaped oxygen scavenger which is excellent in microwave resistance, oxygen absorption performance, and loading property. Is. Therefore, the food packaging for microwave oven cooking, since the sheet-shaped oxygen absorber has excellent oxygen absorption performance,
It is possible to maintain the quality of foods that are being stored and to store them for a long time. In particular, since the sheet-shaped oxygen scavenger is excellent in microwave oven resistance, there are safety and hygiene problems such as bag breakage due to microwave irradiation and discharge of contents, which were a concern with conventional iron powder oxygen scavengers. Instead, a consumer who purchases a food package for microwave oven cooking can simply and safely worry about microwave irradiation, heating, and cooking in a microwave oven. Further, food manufacturers, distributors or distributors, etc., by low-temperature and frozen storage of food as the food package of the present invention, production, inventory adjustment, heat cooking by microwave irradiation in a short time, Can be supplied to consumers. Further, the sheet-shaped oxygen absorber is easy to produce,
Since the loadability of the food package is excellent, the productivity of the food package for microwave oven cooking is high and commercial production is possible. Thus, the food package for microwave oven cooking of the present invention is not only excellent in performance, but can also be used as a food product for preserving the quality of various foods that are heated and cooked in a microwave oven, including semi-cooked and cooked foods. , Greatly contribute to the spread of food for microwave oven cooking.

[Brief description of drawings]

FIG. 1 Example of microwave food package (cross-sectional view)

FIG. 2 Example of microwave food package (cross-sectional view)

FIG. 3 Example of microwave food package (cross-sectional view)

[Explanation of symbols]

1 sheet type oxygen absorber 2 Barrier-type container 21 lid 22 Inner packaging container Food for 3 microwave cooking

Continuation of the front page (56) Reference JP-A-2-413 (JP, A) JP-A-2-72851 (JP, A) JP-A-5-65176 (JP, A) JP-A-6-329178 (JP , A) Japanese Unexamined Patent Publication No. 7-67594 (JP, A) Actual Development 5-63833 (JP, U) Actual Development 4-109141 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) B65D 81/34 B65D 81/26 A23L 3/00 101

Claims (2)

(57) [Claims] 1. A deoxidizing sheet obtained by kneading an iron-based oxygen scavenger composition with a thermoplastic resin to form a food sheet.
A food package for cooking in a microwave oven, which is sealed in a gas barrier container together with a sheet-shaped oxygen scavenger in which a part or all is covered with a breathable packaging material . 2. An oxygen scavenging sheet obtained by kneading an iron-based oxygen scavenger composition with a thermoplastic resin to form a sheet, or at least a part thereof.
Sheet deoxidizer Tona coated all breathable packaging material
An oxygen scavenger for food packaging for microwave cooking .