JPS6021978Y2 - packaged food - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a flat-shaped packaged food, and more particularly to the structure of a flat-shaped packaged food in which the package does not expand or burst when heated during microwave sterilization or cooking.

Microwaves are electromagnetic waves that are also called ultra-high frequency waves.
．． Wavelength of 3-30c1rL, i.e. 1-1OOGH
Recently, it has been attracting attention as a means of heating foods following high-frequency heating, and is being applied to microwave ovens and the like.

Microwaves have a loss coefficient [(permittivity E) x (permittivity t
Materials with a small anδ) generate little heat, but materials with a large loss coefficient generate a lot of heat, and because they have the property of reflecting when they hit metal, it is effective for heating packaged foods using packaging materials with a small loss coefficient. It is a method.

When heating food using microwaves, the food is placed in a metal cavity and microwaves are radiated from the magnetron antenna above.The microwaves are reflected by the metal walls, so the food is exposed to the microwaves from the top, bottom, left and right. It can be irradiated with waves and can be heated entirely.

Furthermore, even if food is packaged in materials with a low loss coefficient, such as plastic or paper, microwaves will pass through these packaging materials without absorbing them, so only the food inside can be heated. can.

For this reason, microwaves are an effective means for heating packaged foods, especially hermetically packaged foods, for sterilization or cooking.

However, heating by microwaves heats the food from the part where the microwave hits the food, so the packaged food is heated from the outside part.

Furthermore, since foods are generally a mixture of many types, each having a different loss coefficient, the heat generated by microwaves inside the food tends to be non-uniform.

This creates a temperature difference between the outer and inner parts of the packaged food.

Furthermore, foods with irregular shapes, especially flat foods, for example, in the case of a hamburger steak, the surrounding area is heated from three directions, while the center is heated from two directions, so the temperature of the surrounding area is Although the temperature is high, the central part is still not heated, and the temperature difference can reach 40°C.

Such a temperature difference becomes a fatal defect when heat sterilizing packaged foods, especially hermetically packaged foods.

This is because the center part of the food has not yet reached the heat sterilization temperature, but the outer part or the surrounding part has already reached the temperature of sterilization.
This is because when heated to 0°C, the water boils, causing the package to expand or burst.

In order to prevent the packaging from bursting during heat sterilization, attempts have been made to place the entire metal cavity under pressure when heat sterilizing packaged foods using microwaves.
This method has the disadvantage that not only the equipment itself is expensive, but also the operating costs are high, and furthermore, the continuous operation of the method itself is difficult.

Furthermore, since the outside or peripheral portion of the food itself is exposed to high temperatures for a long period of time, the outside or peripheral portion becomes harder than the central portion, which also has the disadvantage of deteriorating its texture.

In the case of flat packaged foods, attempts were made to heat sterilize them using microwaves by fitting a metal jig into the side of the food, but this method required extra steps to attach and remove the jig. There is a disadvantage.

The inventors of the present invention have conducted repeated research in order to overcome the above-mentioned defects of flat-shaped foods in heat sterilization using microwaves, and by blocking microwaves irradiated from the sides of flat-shaped packaged foods. They discovered that the above defects could be overcome and completed the present invention.

An object of the present invention is to provide a flat packaged food product whose packaging does not expand or burst during heat sterilization using microwaves.

The present invention consists of a flat food, two disc ring-shaped materials placed on the upper and lower parts of the sides of the food that reflect microwaves but do not transmit them, and two discs placed on the top and bottom of the flat food. This flat packaged food is made of a film or sheet of material that transmits microwaves, and is completely hermetically sealed.

A specific example of the flat food in the present invention is a hamburger steak, a specific example of a material that reflects microwaves but does not transmit them is aluminum foil, and a specific example of a material that transmits microwaves is aluminum foil. There are plastics, but
Due to the nature of the present invention, it is not limited to these.

A specific example of the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal cross-sectional view of the packaged food of the present invention, in which 1 is a hamburger steak, 2 is two discs of ring-shaped aluminum foil placed on the upper and lower sides of the hamburger steak 1, After being sealed, these pieces come together to form a cylindrical ring with a flange on the side of the hamburger steak 1.

3 is a plastic film that wraps the whole thing.

As shown in FIG. 3, the packaged food according to the specific example of the present invention has a circular ring-shaped aluminum foil 2 on a plastic film 3.
A hamburger steak 1 is placed on top of the hamburger steak 1, a disc ring-shaped aluminum foil 2 is placed on top of the hamburger steak 1, a plastic film 3 is further placed on top of the aluminum foil 2, and the whole is vacuum-packed.

During vacuum packaging, two disc-ring-shaped aluminum foils cover the sides of the hamburger steak 1, and the remaining portion becomes a brim between the plastic films 1.

The sides of the flat food in the packaged food of the present invention are coated with a material that reflects microwaves and does not transmit them, so when the packaged food is heated by microwaves, it is irradiated from the side. Microwaves are reflected and scattered,
Packaged foods are irradiated with microwaves only from the top and bottom of their flat form, so flat foods are heated evenly from only the top and bottom directions.

Therefore, only the surrounding area of the flat food is not overheated, and the entire area is heated at a nearly uniform temperature, so there is no chance of the package expanding or bursting due to localized boiling of water during microwave heating. do not have.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a flat packaged food according to the present invention, FIG. 2 is a partially cutaway perspective view thereof, and FIG. 3 is a perspective view showing each material in the packaging of the packaged food according to the present invention. 1: Hamburger Steak, 2 Ni Aluminum Foil, 3 Ni Blast Stick Film.

Claims (1)

[Scope of utility model registration request] Food in a flat form, placed on the upper and lower parts of its sides2
It consists of a circular ring-shaped material that reflects microwaves but does not transmit them, and two films or sheets of materials that transmit microwaves placed above and below a flat food product, and the whole is sealed and packaged. A flat-shaped packaged food characterized by: