WO2016017395A1 - Microwave oven-heatable package and container used for same package - Google Patents

Abstract

In the present invention, a microwave oven-heatable package, in which a food item (1) to be heated by a microwave oven is accommodated in a container (3), is characterized in that a coating layer (5) that is made of an edible wax or an edible oil with a melting point in the range of 30-95˚C is provided between the food item (1) and an inner surface of the container (3). This package enables a viscous and sticky food item such as a rice cake to be effectively heated in a microwave oven while the food item is accommodated inside the container, without the use of an expensive release agent such as silicone.

Description

Package for microwave heating and container used for the package

The present invention relates to a microwave oven-compatible package, and more particularly to a microwave oven-compatible package capable of heating the food by microwave heating in a state where the food is contained, and a container used for the package. Is.

A microwave oven is a device that irradiates microwaves to vibrate water molecules contained in an object in the range and heats the object in the range through a rise in water temperature, and is generally applied to heating food.

With the widespread use of such microwave ovens, microwave oven-compatible packages that can heat the food contained in the container together with the microwave oven have come to be widely used. The container used for such a microwave oven-compatible package is made of a microwave-permeable material (specifically, a non-metallic material such as plastic or paper), and depends on the form of the container. The range heating is performed in a state in which the lid member is removed or in a state in which a vent hole is formed so that water vapor is removed.

That is, the food contained in the package for microwave heating as described above can be heated as it is without transferring it to a saucer or the like, so it is highly convenient and widely used.

By the way, in the package for microwave heating as described above, when the stored food is heated and easily becomes sticky with high viscosity, the heated food adheres to the inner surface of the container, There is a problem that it becomes difficult to separate. For example, food such as candy corresponds to this.

As a means for preventing such an inconvenience, for example, Patent Document 1 proposes a bag container made of a film coated with silicone as a release agent.

JP-A-10-136919

In Patent Document 1, since the cocoon can be heated in a microwave oven together with the container, and the silicone coating layer is formed on the film surface, the heated cocoon does not adhere to the film as a container and quickly. It has the advantage that it can be separated from the container.

However, since the container as described above uses expensive silicone, it is unsatisfactory in terms of cost. In particular, food such as rice cake is an inexpensive food, so the disadvantage in terms of cost is a major factor that hinders its practical application.

Therefore, the object of the present invention is to store a food product that does not use an expensive release agent such as silicone, even when a food product that is sticky and sticky due to heating, such as rice cake, is contained in the container. An object of the present invention is to provide a microwave oven-compatible package capable of effectively heating a microwave oven as it is.
Another object of the present invention is to provide a container suitably used for the package.

According to the present invention, there is provided a microwave oven-compatible package in which food to be heated in a microwave is contained in a container, and the melting point is in the range of 30 to 95 ° C. between the food and the inner surface of the container. There is provided a package for microwave heating, which is provided with a coating layer of wax or edible oil / fat.

In the microwave heating package for the present invention,
(1) The coating layer is provided on the inner surface of the container or the surface of the food,
(2) the coating layer is formed of an edible wax having a melting point in the range of 50 to 95 ° C .;
(3) the coating layer is formed in an amount of 1 to 450 g / m ² ;
(4) the container has the form of a cup, tray or pouch;
(5) The food is a candy,
Is preferred.
Further, according to the present invention, there is provided a microwave oven-compatible container for containing food to be heated in a microwave oven, wherein an edible wax or edible fat having a melting point in the range of 30 to 95 ° C. is provided on the inner surface of the container. A container for microwave heating is provided, which is provided with a coating layer.

In the microwave oven-compatible package of the present invention, a coating layer of edible wax or edible oil and fat having a melting point in the range of 30 to 95 ° C. is provided between the contained food and the inner surface of the container. Thereby, the adhesion to the container inner surface of the food heated with the microwave oven is suppressed effectively.
Therefore, even when the heated food becomes sticky and sticky like a candy, it is possible to effectively prevent adhesion to the inner surface of the container without impairing the safety as food. Can be promptly separated.
For example, not only when food heated in a microwave oven is taken out hot, but also when it is taken out in a cold state, since the coating layer is interposed between the food and the inner surface of the container, the food is contained in the container. It does not adhere to the inner surface.

In addition, the above edible waxes and edible oils and fats are extremely cheap compared to a release agent such as silicone, and are approved as so-called food additives, and are effective in increasing costs without compromising food safety. Can be avoided.

Furthermore, in the present invention, the coating layer only needs to exhibit slipperiness with respect to the food when the food is in a state of being easily sticky and sticky due to microwave heating, and the state before the food is heated. Then, slipperiness does not need to be exhibited. For this reason, even if the amount of the coating layer provided in the container of the present invention is small at room temperature, when the coating layer is heated to a temperature higher than the melting point and becomes liquid, the coating layer flows. By spreading and spreading uniformly on the surface where the food and the inner surface of the container are in contact with each other, it is possible to exhibit stable slipping and reliably prevent the heated food from adhering to the inner surface of the container.
In the present invention, the above-mentioned coating layer can be provided on the inner surface of the container or the surface of the food, but since the amount of the coating layer may be small, the influence on the flavor of the food is less and the cost is also reduced. It becomes even more advantageous.

Furthermore, since the coating layer of edible wax or edible oil / fat is a solid at room temperature, the package for microwave heating according to the present invention is easy to transport and handle containers or foods before packaging foods. There is also an advantage. That is, when the coating layer is in a liquid state at room temperature, the coating layer is likely to fall off when the container or food is transported. However, in the present invention, such a problem can be avoided.

The figure which shows the state of the foodstuff and the container inner surface in the state in which the foodstuff was accommodated in the package for microwave heating of this invention. In the microwave oven heating-compatible package of the present invention, it is an enlarged cross-sectional view for explaining the function of the coating layer, (a) is a view in a state where the coating layer is provided on the inner surface of the container, (b) is It is a figure in the state in which the coating layer was formed in the foodstuff. It is a figure which shows the cup-shaped container used suitably for the microwave oven heating-compatible package of this invention, (a) is a top view, (b) is a half cross-sectional side view.

With reference to FIG. 1, the microwave oven-compatible package of the present invention is provided with a coating layer 5 for enhancing the slipperiness with respect to the food 1 between the food 1 to be microwave-heated and the inner surface of the container 3. It has the basic structure.

Food 1;
The food 1 contained in the container is not particularly limited as long as it contains water that can be heated by a microwave oven, but generally becomes a viscous and sticky fluid by microwave heating, For example, salmon, udon, buckwheat, cooked rice, etc. are typical, and especially salmon is a food product to which the present invention is most suitably applied because it becomes pasty when heated.

Container 3;
The material of the container 3 is not particularly limited as long as it can be heated in a microwave oven, specifically, a non-metallic material that is microwave permeable. Plastic or paper is used, and a thermoplastic is particularly preferable in that the retainability of the coating layer 5 described later is good.

Examples of the thermoplastic plastic as described above may include the following ones on the condition that they have a high melting point that does not deform during microwave heating.
Olefin resins such as low density polyethylene, high density polyethylene, polypropylene, poly 1-butene, poly 4-methyl-1-pentene or α-olefins such as ethylene, propylene, 1-butene, 4-methyl-1-pentene Random or block copolymers, cyclic olefin copolymers, etc .;
Ethylene / vinyl copolymers, such as ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer, ethylene / vinyl chloride copolymer, etc .;
Styrenic resin such as polystyrene, acrylonitrile / styrene copolymer, ABS, α-methylstyrene / styrene copolymer, etc .;
Vinyl resins such as polyvinyl chloride, polyvinylidene chloride, vinyl chloride / vinylidene chloride copolymers, polymethyl acrylate, polymethyl methacrylate, etc .;
Polyamide resin, for example, nylon 6, nylon 6-6, nylon 6-10, nylon 11, nylon 12, etc .;
Polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, and copolyesters thereof;
Polycarbonate resin;
Polyphenylene oxide resin;
Biodegradable resins, such as polylactic acid;
Needless to say, a blend of these thermoplastic resins can be used as the container 3 as long as the moldability is not impaired.

In the present invention, among the thermoplastic plastics described above, an olefin-based resin is particularly optimal in that it has a high affinity for the coating layer 5 described later and exhibits high wettability.

In addition, the container 3 formed using the thermoplastics as described above can have a multilayer structure as appropriate. For example, a gas barrier resin typified by an ethylene / vinyl alcohol copolymer is provided as an intermediate. In this case, a maleic anhydride-modified olefin may be used to enhance the adhesion between the gas barrier resin layer of the intermediate layer and the inner and outer layers (for example, an olefin resin layer or a polyester resin layer). An adhesive resin such as a resin can also be provided.

Further, in the paper container 3, the above-mentioned thermoplastic layer may be provided on the inner surface on which the coating layer 3 described later is formed.

Coating layer 5;
In the present invention, the coating layer 5 is provided on the inner surface of the container 3 (the surface on which the food to be brought into contact) or the surface of the food 1. Such a coating layer 5 has a melting point in the range of 30 to 95 ° C. It is formed by the edible wax or edible fat / oil in
That is, the edible wax is a wax approved as a so-called food additive, for example, a vegetable wax or an animal wax, which is an ester of a higher fatty acid and a higher alcohol, and the edible fat is a vegetable-derived fat. , An ester of fatty acid and glycerin, both of which have high water repellency, exhibit extremely high slipperiness for foods that are heated in a microwave oven, and have a melting point within the above range. Although it is solid at room temperature, it becomes liquid when it is heated in a microwave and comes into contact with water vapor. That is, since the food 1 heated in the microwave oven comes into contact with the coating layer 5 in the liquid state, the contact area between the food 1 and the coating layer 5 is larger than that when the coating layer 5 is in the solid state. It has become extremely large. For this reason, the high slidability with respect to the foodstuff 1 of the edible wax and edible oil and fat which the coating layer 5 forms is exhibited to the maximum, and as a result, the foodstuff 1 will be in the state which is easily sticky and sticky in the state heated by the microwave oven. Even so, the food 1 is effectively prevented from adhering to the inner surface of the container 3, and the food 1 can be quickly separated from the container 3. For example, when the melting point is lower than the above range, liquefaction of the coating layer 5 during heating in the microwave oven is too fast, causing the coating layer 5 to sag, and the sliding property of the coating layer 5 with respect to the food 1 is reduced. It will not be able to fully demonstrate. Moreover, when melting | fusing point is higher than the said range, the liquefaction of the coating layer 5 at the time of microwave oven heating will become inadequate, and also the slipperiness with respect to the foodstuff 1 of the coating layer 5 may fully be exhibited. Can not.

In the present invention, specific examples of the edible wax and edible fat / oil described above can be exemplified as follows on the condition that the melting point is within the above-described range.
Edible wax;
Animal waxes such as carnauba wax, candelilla wax, rice wax, plant wax such as wood wax, and beeswax.
Edible oils and fats;
Vegetable oils such as palm oil, coconut oil and cocoa butter.

In the present invention, an edible wax having a melting point in the range of 50 to 90 ° C. is preferable from the viewpoint that it is particularly easy to obtain those having the above melting point range and that it is difficult to liquefy before heating in a microwave oven even at high room temperature.

Moreover, the coating layer 5 formed from the above edible wax or edible oil / fat should just be formed so that the whole surface which the foodstuff 1 contacts in the state which became the liquid state by the microwave oven heating may be covered. The amount of edible wax or edible oil / fat for forming the coating layer 5 may be very small. For example, in a state where the coating layer 5 is scattered on the inner surface of the container 3 (see FIG. 2A), or in a state where the coating layer 5 is scattered on the surface of the food 1 ( When the coating layer 5 is heated to the melting point or higher, the coating layer 5 spreads, and the coating layer 5 is always interposed between the food 1 and the inner surface of the container 3. The adhesion of the heated food 1 to the inner surface of the container 3 is effectively prevented.

Furthermore, in the present invention, it is preferable that the coating layer 5 is formed of edible wax or edible oil and fat in an amount of 1 to 450 g / m ² , particularly 1 to 25 g / m ² . If this amount is too small, the slipperiness will be uneven, and a part of the food 1 may adhere to the inner surface of the container 3, and even if the amount is excessively increased, the cost will increase. There is a possibility that the food after heating may be sticky or affect the flavor of the food.

The coating layer 5 as described above is, for example, edible wax or edible oil / fat that has been heated or dissolved in ethanol to form a liquid, spray coating using an air gun or the like, solid edible wax or edible oil / fat with a heat stamp, etc. It can be easily formed by a stamp method that presses against a predetermined portion of the container 3 or the food 1 using the above jig.

Form of container 3;
The container 3 in the present invention has various forms depending on the form of the food to be stored, as long as the heating by the microwave oven is performed in a form in which the water vapor generated from the food 1 is effectively discharged during the heating by the microwave oven. Can be taken. For example, you may have a form of a cup, a tray, and a pouch (bag).

FIG. 3 shows a container 3 having a cup shape particularly suitable when the food 1 is a candy.
As can be understood from the plan view of FIG. 3A, the container 3 has a rectangular plane as a whole, and as shown in the half sectional side view of FIG. A bottom portion 10, a barrel portion 11 rising from the bottom portion 10, and a flange portion 13 projecting outward from the upper end of the trunk portion 11. A raised bottom portion 10a is formed to alleviate thermal deformation.

Such a container 3 is manufactured by vacuum molding such as plug assist molding of a sheet formed by an extruder using the above-described thermoplastic plastic. Note that the tray-shaped container has substantially the same shape as the cup-shaped container 3 except that the height of the body portion 11 is low, and is manufactured by the same method.

In the present invention, when the above-described coating layer 5 is provided on the inner surface of the bottom portion 10 and the trunk portion 11 of the cup-shaped container 3 as described above, the coating layer 5 is not provided on the upper surface of the flange portion 13. . This is because a lid (not shown) is fixed to this portion by heat sealing.

After the container 3 provided with the coating layer 5 accommodates food such as rice cake, at least the inner peripheral edge is fixed by heat sealing with a heat sealable resin, and the contents are accommodated. It is commercially available as a packaging container for heating with a microwave oven.

In addition, the form of the cover material provided by heat sealing after accommodating food can be made into an appropriate shape according to the microwave heating method.
For example, when microwave heating is performed after the lid material is peeled off, the lid material may have the same form as that provided in a normal cup container. May be formed of a metal foil such as an aluminum foil, as long as it is formed of a heat-sealable resin.
On the other hand, when microwave heating is performed with the lid attached, the lid is all made of a plastic material such as an olefin resin, and at the same time forms weak lines such as perforations, Prior to the range heating, it is necessary to break a part of the lid member to form a vent hole. Further, in this case, it is desirable to provide the above-described coating layer 5 on the inner surface of the lid member, except for the peripheral portion to be heat sealed. It is because the food heated by the microwave oven also contacts the inner surface of the lid.

In addition, although the cup-shaped container 3 shown by FIG. 3 has a rectangular planar shape, this shape can be changed according to the form of the food accommodated, for example, a round bowl For example, the planar shape can be circular.

Further, when the container 3 is a pouch in the form of a bag, prior to microwave heating, a part of the pouch is cut out to form a vent or a pouch equipped with a vapor venting mechanism is used. It will be necessary.

In the above-described container for microwave heating, in which the coating layer 5 is formed on the container 3 of the present invention, the coating layer 5 having high water repellency and high slipperiness with respect to food becomes liquid upon microwave heating. Even when the food is fully viscous and heated to a sticky state, the container can be effectively prevented from adhering to a food that becomes sticky and sticky.

The present invention will be described in the following experimental examples.
The coating material (coating layer forming material), food, container, and adhesion evaluation method used in each experimental example are as follows.
<Coating material>
Edible wax Carnauba wax (melting point: 85 ° C)
Beeswax (melting point: 65 ° C)
Rice wax (melting point: 77 ° C)
Polyethylene wax (melting point 110 ° C)
<Container>
Resin square tray (inner layer: PP intermediate layer: oxygen absorbent outer layer: PP)
Paper cup (inner layer: PE outer layer: paper)
<Food>
Spider cut into a size of 6.5cm x 4.0cm x 1.5cm

<Adhesion evaluation method>
The container was filled with food (corn koji), heated in a microwave oven at 1000 W for 30 seconds, taken out and radiated for 10 seconds, and the koji was taken out of the container by hand. The degree of remaining soot was evaluated according to the following criteria.
○: There is no adhesion and it can be taken out as it is.
Δ: Slightly adheres, and the hook is caught when taken out.
X: There is adhesion, and the wrinkles extend when taken out.

[Experimental Examples 1-3]
After using a resin square tray as the container, using rice wax as the coating material, and forming the coating layer in the amount shown in Table 1, putting the square candy as food, heating in a microwave oven, and then evaluating the adhesion The results are shown in Table 1.
The coating layer was formed on the inner surface of the container as follows.
That is, 1 g of a coating material (rice wax) was dissolved in 100 ml of ethanol, and the required amount shown in Table 1 was sprayed on the inner surface of the container by spraying and dried to form a coating layer.

[Experimental Example 4]
Except for using a paper cup as a container, a coating layer made of rice wax was formed in exactly the same manner as in Experimental Example 1, and microwave heating was performed with square horns, and the adhesion was evaluated. The results are shown in Table 1.

[Experimental Example 5]
A coating layer was formed in the same manner as in Experimental Example 1 except that carnauba wax was used as the coating material, and the adhesion was evaluated by heating in a microwave oven with square horns. The results are shown in Table 1.

[Experimental Example 6]
A coating layer was formed in the same manner as in Experimental Example 1 except that beeswax was used as the coating material, and the adhesion was evaluated by heating in a microwave oven with square horns. The results are shown in Table 1.

[Experimental Examples 7 to 9]
Rice wax was used as the coating material, and the coating layer of the amount shown in Table 1 was formed on the square hook. The square hook was placed in a resin square tray (container), heated in a microwave oven, and then evaluated for adhesion. The results are shown in Table 1.
In addition, formation of the coating layer to a square hook was performed as follows.
That is, the square candy was taken out of the bag, and a coating solution (rice wax) 1 g dissolved in 100 ml of ethanol was wiped with a spray with a necessary amount shown in Table 1 and dried to form a coating layer.

[Experimental Example 10]
A resin square tray was used as the container, and the square hooks were put in the container and heated in a microwave oven, and then the adhesion was evaluated. The results are shown in Table 1.

[Experimental Example 11]
A coating layer is formed on the inner surface of a container (resin tray) in the same manner as in Experimental Example 1 except that polyethylene wax is used as the coating material. Was evaluated. The results are shown in Table 1.

[Experimental example 12]
A coating layer is formed on the inner surface of the container (resin tray) in the same manner as in Experimental Example 1 except that the coating amount of rice wax (coating material) is changed to 0.5 g / m ^2. Then, after heating in a microwave oven, the adhesion was evaluated. The results are shown in Table 1.

[Experimental Example 13]
Except for changing the coating amount of rice wax (coating material) to 0.5 g / m ² , a coating layer was formed on the square hook in the same manner as in Experimental Example 7, and this square hook was placed in a container (resin tray). After heating in a microwave oven, the adhesion was evaluated. The results are shown in Table 1.

As is apparent from the adhesion evaluation results shown in Table 1, by forming a coating layer with edible wax on the container or food, the food after heating in the microwave does not adhere to the container and quickly separates from the container. I can see that

1: Food 3: Container 5: Coating layer 10: Bottom 11: Body 13: Flange

Claims (8)

A microwave-heated package in which food to be heated in a microwave oven is contained in a container, and a coating of edible wax or edible oil and fat having a melting point in the range of 30 to 95 ° C. between the food and the inner surface of the container A package for microwave heating, characterized in that a layer is provided. The package for microwave heating according to claim 1, wherein the coating layer is provided on the inner surface of the container. The package for microwave heating according to claim 1, wherein the coating layer is provided on a food surface. The package for microwave heating according to claim 1, wherein the coating layer is formed of an edible wax having a melting point in the range of 50 to 95 ° C. The package for heating with a microwave oven according to claim 1, wherein the coating layer is formed in an amount of 1 to 450 g / m ² . The package for microwave heating according to claim 1, wherein the container has a shape of a cup, a tray or a pouch. The package for microwave heating according to claim 1, wherein rice cake is contained as the food. A microwave oven-compatible container for containing food that is heated in a microwave oven, and an inner surface of the container is provided with a coating layer of edible wax or edible oil and fat having a melting point in the range of 30 to 95 ° C. A microwave oven-compatible container characterized by the above.

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