JP3383382B2 - Food heating cooking package - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of packaging food when heating the food in a microwave oven to prevent the food from sticking due to dripping or dew condensation. The present invention relates to a food heating and cooking package to be prevented. 2. Description of the Related Art In recent years, the prevalence of microwave ovens at home has reached 85%, and it has become common to cook and reheat food in a microwave oven. The heating mechanism of the microwave oven is an internal heating method in which the water inside the food is vibrated by microwaves and heated by frictional heat generated at that time.
The features of internal heating include advantages such as short heating time, little loss of nutrients, and low power consumption.
It has disadvantages such as a large amount of water evaporation and a large amount of drip. [0003] On the other hand, the advancement of women into
With social changes such as an increasing tendency to individualize foods, opportunities for using prepared foods are increasing. That is, an increase in the shipping ratio of cooked and frozen foods and an increase in the sales ratio of prepared foods are recognized. In order to easily reheat such cooked foods in a short time, a microwave oven is effective. However, the taste of the foods heated due to the disadvantages of the internal heating described above is higher than that of the conventional method using external heating. It is inferior at present. [0004] In general, when food is heated in a microwave oven, foods with a small amount of outside moisture, such as fried foods and grilled foods, are heated as they are to evaporate water, and other foods are heated after being covered with plastic wrap. It is said that it is appropriate to prevent food from evaporating and to add moisture, such as steamed food, by once passing the food through water and then covering it with wrap and heating. However, it is troublesome that the heating method is different depending on the food, and if the food is heated as it is, dirt and odor adhere to the inside of the microwave oven. However, since wraps represented by polyvinylidene chloride and polyethylene do not have moisture permeability, water vapor generated from food tends to condense on the wrap surface and migrate to the food to give a sticky texture. In addition, meat and fish that have a large amount of free water tend to shrink muscle fibers when heated, and drip is likely to occur. Lower. In order to solve the above-mentioned drawbacks, when using a wrap, an absorbent sheet such as cooking paper is laid under the food or covered with a breathable and waterproof sheet in place of the wrap (Japanese Unexamined Patent Publication No. No. -200575). In the former, the problem of the drip accumulating at the bottom of the food is improved because the water-absorbent sheet absorbs the drip, but since the sheet that has absorbed the drip comes into direct contact with the food, the stickiness on the bottom of the food is completely eliminated. Not resolved. In addition, the problem of condensation due to the generated water vapor has not been solved. On the other hand, since the latter covers the food with a breathable sheet, the water vapor generated from the food is released to the outside, so that dew condensation is improved, but the food is eaten with relatively high moisture like steamed food. The product is not preferable because drying and curing occur.
In addition, this method does not solve the stickiness of the lower part of the food due to the drip. In recent years, as a packaging material for microwave oven heating, a water-absorbent fiber sheet of a laminate of a hydrophobic fiber sheet and a water-absorbent fiber sheet having a permeability of 10 cc / cm ² / sec or more and a water resistance of 5 cm or more has been proposed. A sheet in which an air-impermeable sheet is laminated on the side (Japanese Utility Model Laid-Open No. 3-108671) has been proposed. In this product, the water vapor generated from food passes through the hydrophobic fiber sheet and the absorbent fiber sheet, hits the impermeable sheet and forms dew, and the water is absorbed by the absorbent fiber sheet. Be improved. However, moisture such as drip cannot pass through the hydrophobic fiber sheet and accumulates under the food, so that stickiness due to drip has not been solved. SUMMARY OF THE INVENTION An object of the present invention is to dry or harden food due to evaporation of water, and to cause food dew or drip due to water vapor generated when cooking and reheating food in a microwave oven. An object of the present invention is to provide a package capable of heating various foods deliciously while preventing stickiness and the like. According to the present invention, in order to solve the above problems, according to the present invention, a hydrophobic fiber sheet that allows moisture to pass through an inner layer in contact with food, an absorbent fiber sheet that absorbs and holds moisture in an intermediate layer, and a water impervious outer layer The hydrophobic fiber sheet has an average fiber-to-fiber distance of 35 μm or more, and the laminated sheet has a moisture permeability of 100 g / m ² / day or less. From 100 to 500 g / m ² is provided. When the food is wrapped in the package and heated in a microwave oven, the steam and drip generated from the food pass through the hydrophobic fiber sheet of the inner layer and reach the absorbent fiber sheet of the intermediate layer. It is absorbed and held by the absorbent fiber sheet. Inside the absorbent fiber sheet is the above-mentioned hydrophobic fiber sheet, which prevents the absorbent fiber sheet that has absorbed water from coming into direct contact with food, and the outer layer of the absorbent fiber sheet has a synthetic resin film. This prevents evaporation of water to the outside, so that stickiness and overdrying of the food are prevented, and as a result, the food can be heated deliciously. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an example of a laminated sheet constituting the package of the present invention.
A hydrophobic fiber sheet 2 that allows moisture to pass through an inner layer that is in contact with food, an absorbent fiber sheet 3 that absorbs and retains moisture in an intermediate layer, and an impermeable synthetic resin film 4 that is laminated on an outer layer 3
It has a layer structure. The hydrophobic fiber sheet 2 allows water vapor and drip generated from food to pass through without absorbing it, and prevents direct contact between the absorbent fiber sheet 3 that has absorbed these water vapor and drip and the food. In terms of its function, it is preferable that the material excels in the passage of water vapor and drip. For example, a non-woven fabric made of synthetic fibers such as polyethylene, polypropylene, and polyester, and having an average inter-fiber distance of 35 μm or more It is desirable that This average fiber-to-fiber distance is an average value of values obtained by dividing 500 by the number of fibers included in a 500 μm line segment that is substantially perpendicular to the orientation direction of the fiber in an arbitrary part where the fiber density is substantially uniform,
It was calculated by the following equation. ## EQU1 ## D: Fiber fineness (denier) A: Area of nonwoven fabric (m ² ) t: Thickness of nonwoven fabric (m) W: Weight of nonwoven fabric (g) If the average inter-fiber distance is 35 μm or less, the fibers themselves Since water does not absorb water, it is difficult for moisture to enter, and water vapor or drip accumulates on the surface without passing through the water, which causes a deterioration in the taste of food. Table 1 shows the passing speed of one drop of water with respect to the average inter-fiber distance. [Table 1] In general, non-woven fabric manufacturing methods include a heat treatment type and a spun bond type.
It is usual to use a fiber diameter of 0.9 denier or more. On the other hand, the melt-blow type nonwoven fabric can use finer fibers than those described above, and usually has a fiber diameter of 0.1 denier or less. The average fiber-to-fiber distance of the nonwoven fabric when using 0.9 denier fiber is 38.7 μm when the basis weight and thickness are equal, and 12.9 μm when using 0.1 denier fiber. Become. The absorbent fiber sheet 3 constituting the intermediate layer is not limited to natural fibers and synthetic fibers as long as it has water absorbency, but is preferably made of natural fibers such as pulp fibers and regenerated cellulose fibers. good. Further, a superabsorbent polymer represented by a polyacrylic acid copolymer can be used alone or in combination with the above-mentioned sheet. The form of the sheet may be one in which fluffy absorbent fibers are directly laminated on the hydrophobic fiber sheet 2, or one in which absorbent fibers made of paper or nonwoven fabric are laminated with the hydrophobic fiber sheet 2. May be. In the latter case, for controlling the absorbent, but it is also possible to laminate the absorbent fiber sheet 3 and 3 of two or more as shown in FIG. 2, the layer
It is preferable that the sheets be integrated by a method such as embossing or heat sealing, because separation between the sheets is likely to occur. The synthetic resin film 4 used for the outer layer
Is to prevent the moisture absorbed in the absorbent fiber sheet 3 of the intermediate layer from leaking to the outside and to prevent the water vapor from passing to the outside. Polyethylene, polypropylene, polyester and the like can be used. The material is not particularly limited as long as it has no water permeability and the moisture permeability is 100 g / m ² / day or less. Further, as shown in FIG. 3, the paper 5 can be laminated on the outer layer of the synthetic resin film 4.
In this case, the suitability for printing on the outer surface of the sheet is improved, and the workability during bag making is also improved. As a method of laminating the three types of sheets,
After adsorbing the absorbent fiber sheet 3 and the hydrophobic fiber sheet 2 by heat sealing, the synthetic resin film 4 by a T-die is used.
A method of performing the lamination is generally a layer in use
Not particularly limited as long as during peeling does not occur. The moisture permeability of the laminated sheet is 100 g / m ² / day.
And the water absorption from the hydrophobic fiber sheet side is 100
５００500 g / m ² , more preferably 150-300 g
/ M ² . In actual use, the laminated sheet 1
Into a shape that can hold a bag or other food,
The food is wrapped inside and heated for a predetermined time by a microwave oven. The steam and drip generated from the food immediately pass through the hydrophobic fiber sheet 2 in the inner layer, reach the absorbent fiber sheet 3 in the intermediate layer, and are absorbed and held by the absorbent fiber sheet 3. In this case, the hydrophobic fiber sheet 2 is provided inside the absorbent fiber sheet 3 to prevent the absorbent fiber sheet 3 holding moisture from coming into direct contact with food, and to form an outer layer of the absorbent fiber sheet 3. Has a synthetic resin film 4
In order to prevent the leakage of moisture to the outside, stickiness and overdrying of the food are reliably prevented, and contamination of the turntable by a permeated substance such as moisture or oil is also prevented. [0022] The thing which should give moisture like steamed food is
It is preferable that the absorbent fiber sheet 3 of the intermediate layer is impregnated with moisture before heating. The water impregnated in the intermediate layer is heated by a microwave oven to become steam, but does not leak outside due to the synthetic resin film 4.
The inside of the package is filled, and the food can be heated like a steamer. << Experimental Examples >> Next, results of performance experiments performed on the package of the present invention will be described. In the experiment, a product of the present invention and a comparative example having the following configuration were prepared, various foods were put in each of them, and the foods were heated for a predetermined time by a microwave oven. To compare the moisture, hardness, and texture of the food after heating with the blank 1 heated by the heating method and the blank 2 heated with a microwave oven by wrapping these foods in a polyvinylidene chloride wrap. Was performed. In the case of the steamed product of the present invention and the comparative example, the inner layer sheet of the bag-shaped package was impregnated with 10 cc of water and heated. The evaluation of the texture of each of the above-mentioned foods was performed by a method in which five points were assigned to the blank 1 and the blank 2 was assigned to one point. Table 2 shows the experimental results. [Invention 1] Two thin papers are heat-embossed as absorptive fiber sheets on a hydrophobic fiber sheet composed of a nonwoven fabric made of a heat-bonded synthetic fiber having an average fiber-to-fiber distance of 58 μm, and polyethylene is used as a synthetic resin film. Was used, and the laminated sheet was formed into a bag shape. The moisture permeability of this laminated sheet is 65 g / m ² /
The day and the water absorption are 255 g / m ² . [Invention 2] Thin paper carrying a highly water-absorbing polymer as an absorbent fiber sheet is laminated on a hydrophobic fiber sheet made of a nonwoven fabric made of a heat-bonded synthetic fiber having an average fiber-to-fiber distance of 70 μm. A laminated sheet obtained by laminating polyethylene was used as the resin film, and the laminated sheet was formed into a bag shape. The moisture permeability of this laminated sheet is 10 g
/ M ² / day and water absorption is 303 g / m ² . [Invention 3] Two thin papers are laminated as an absorbent fiber sheet on a hydrophobic fiber sheet made of a nonwoven fabric made of a heat-bonded synthetic fiber having an average fiber-to-fiber distance of 39 μm, and polyethylene is used as a synthetic resin film. This laminated sheet was formed into a bag using a laminated sheet. Moisture permeability of the laminated sheet is 63g / m ² / day, the water absorption amount is 248 g / m ^2. Comparative Example 1 Pulp was laminated on a melt-blown nonwoven fabric having an average fiber-to-fiber distance of 7 μm, and a laminated sheet obtained by laminating polyethylene was formed into a bag. The moisture permeability of this laminated sheet is 62 g / m ² / day, and the water absorption is 58 g / m ² . Comparative Example 2 A nonwoven fabric made of a fibrous superabsorbent polymer was laminated on a nonwoven fabric made of a heat-bonded synthetic fiber having an average fiber-to-fiber distance of 70 μm, and a polyethylene-laminated sheet was formed into a bag. And The moisture permeability of this laminated sheet is 44 g / m ² / day, and the water absorption is 522 g / m
² Comparative Example 3 Two sheets of thin paper were heat-embossed on a melt-blown non-woven fabric having an average fiber-to-fiber distance of 13 μm, and a polyethylene-laminated sheet was formed into a bag. The moisture permeability of this laminated sheet is 70 g / m ² / day, and the water absorption is 241 g / m ² . [Table 2] As described above, the package of the present invention can absorb not only water vapor generated from food at the time of heating but also drip. It is possible to reliably prevent food from sticking due to condensation and drip, and to heat various foods deliciously.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an example of a laminated sheet constituting a package of the present invention. FIG. 2 is a cross-sectional view showing another example of the laminated sheet constituting the package of the present invention. FIG. 3 is a cross-sectional view showing another example of the laminated sheet constituting the package of the present invention. [Description of References] 1 Laminated sheet 2 Hydrophobic fiber sheet 3 Absorbent fiber sheet 4 Synthetic resin film 5 Paper

Claims (1)

(57) [Claims 1] A package for heating a microwave oven, wherein a hydrophobic fiber sheet which allows moisture to pass through an inner layer in contact with food, and an absorbent which absorbs and retains moisture in an intermediate layer A hydrophilic fiber sheet, a laminated sheet formed by laminating a water-impermeable synthetic resin film on an outer layer, wherein the hydrophobic fiber sheet has an average fiber-to-fiber distance of 35 μm or more, and has a moisture permeability as a laminated sheet of 100 g. / ^m 2 / day or less, food cooking packaging body water absorption from the inner layer is characterized by a 100 to 500 g / ^{m 2.}