JPS6151850B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for heating packaged foods, and more particularly to a method for heating packaged foods, which heats packaged contents while controlling the temperature of a plastic film constituting a packaging container.

Conventionally, various methods have been developed and proposed for long-term preservation of food, including retort processing methods for canning, dry food methods that utilize water activity, vacuum packaging to maintain oxygen-free conditions, and gas replacement. There are packaging laws, etc.

However, in the above-mentioned retort processing method, there is a so-called canned smell, and the product is no more than an emergency or portable food, and it is difficult to say that it is delicious. Further, in the above-mentioned dried food method, although the dried food has value as dried fish or dried confectionery, it is different from fresh food. Furthermore, although the above-mentioned vacuum packaging/gas displacement packaging methods can prevent the generation of mold, etc., they have the disadvantage that they promote the growth of anaerobic bacteria and cannot prevent fermentation by yeast. .

In addition, in recent years, a method of boiling sterilization by placing food in synthetic resin bags has been widely used, but this method cannot brown the contents and cannot be applied to aerated foods such as cakes. There is a drawback.

As a result of various studies on long-term food preservation, the inventor of the present invention found that while maintaining the heating temperature of plastic packaging containers at a constant temperature, the temperature of the contents can be increased to a surface temperature that can burn the contents if necessary. The present invention was completed by discovering a method of heating packaged foods that can be heated.

That is, the present invention stores food materials to be baked or cooked in a packaging container made of plastic such as polyester or polypropylene, semi-seals the opening of the packaging container with a ventilation passage, and then closes the packaging container. This method of heating packaged food is characterized by heating the food material inside the packaging container by irradiating it with far infrared rays in a wavelength range that is not absorbed by the plastic that constitutes the packaging container in a hot air atmosphere.

The above-mentioned present invention will be explained in more detail below. First, in the present invention, a bag-like packaging container is manufactured by sealing a film or sheet of synthetic resin such as polyester or polypropylene that does not soften under heat at temperatures below about 120°C. Alternatively, a molded container can be manufactured by molding the above-mentioned material using methods such as blowing or injection. Next, in the present invention, in the packaging container obtained above, foods such as bread, cakes, delicatessens, watery delicacies, etc. for long-term storage are stored uncooked, baked, or semi-finished products. A ventilation path is created by removing a portion of the sealed portion, for example, about 10 to 40 mm, and the remaining portion is completely semi-sealed using a sealing method such as heat sealing or other sealing methods.

Next, in the present invention, the packaging container filled with the contents and semi-sealed as described above is opened in a thermal atmosphere at a temperature approximately 10 to 20 degrees Celsius lower than the softening point of the synthetic resin constituting the packaging container. After putting it inside,
The contents in the packaging container are heated by irradiating far infrared rays in a wavelength range that is not absorbed by the synthetic resin constituting the packaging container using an infrared irradiation lamp or the like.

Accordingly, in the present invention, if the contents in the packaging container become burnt, irradiation with far-infrared rays is stopped, and the contents are heated at the ambient temperature so that the heat passes through to the inside of the contents. Thereafter, in the present invention, the packaging container is removed from the oven, and the unsealed portions are sealed by heat sealing or the like while the packaging container is still hot, thereby completely sealing the packaging container.

In the present invention, if it is desired to maintain the air-containing state even after sealing, the packaging container is passed through a cooling unit in a hygienic atmosphere, for example, with air sterilized using a microfilter of 0.5μ or less, and heated to 60°C. This can be done by cooling the unsealed portion to a temperature below and then sealing the unsealed portion by heat sealing or the like.

As is clear from the above description, the present invention irradiates a packaging container filled with contents with far-infrared rays in a wavelength range that is not absorbed by the synthetic resin constituting the packaging container to remove the contents inside the packaging container. It is something that is heated and cooked. Therefore, in the present invention, the contents inside the packaging container can be baked or cooked without heating the packaging container itself above the oven ambient temperature.

Further, in the present invention, the contents inside the packaging container can be browned while heating the inside of the packaging container.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Cake mix [commercial product containing flour, sugar, glucose, baking powder, etc., Morinaga & Co., Ltd.
Thoroughly mix 250g of the product, 120g of butter, 3 eggs, 100g of sugar, etc. using the specified method, and place in a container made of polypropylene resin. In this container,
The surrounding area was heat-sealed with a composite film made of 12μ polyester film/60μ polypropylene film with an unsealed area of 30mm.

Place this in an oven at 120℃ and use it for 3μ to 6μ
Thereafter, it was heated while being irradiated with far infrared rays preferably having a wavelength of 4 to 6 μm.

While the surface temperature of the film was maintained at 120 to 125°C, the surface temperature of the food content rose to 145°C, causing burntness after 7 minutes. By ceasing far-infrared irradiation, continuing heating for 40 minutes, and heat-sealing the unsealed parts, it was possible to create a pound cake with an appropriate browning that could be stored for a long time.

I left this at room temperature for 3 weeks, but there was no change in taste.
There was no mold growth.

Example 2 Salmon fillet and butter were placed in a composite film bag made of 12μ polyester/60μ polypropylene.
Add an appropriate amount of seasoning, leave a 30 mm unsealed area, and heat seal the periphery. This was placed in a 120°C oven and heated while being irradiated with the far infrared rays shown in Example 1. In this case, it was necessary to irradiate both sides of the bag with far infrared rays, and after 5 minutes, the irradiation was reversed.

After heating for a total of 10 minutes, I was able to heat-seal the unsealed parts and make butter-grilled salmon for long-term storage that was properly browned.

After storing this for 10 days and heating it in boiling water for 3 minutes, the taste was no different from the one after manufacturing.

Claims (1)

[Claims] 1. Food materials to be baked or cooked are placed in a packaging container made of plastic such as polyester or polypropylene, the opening of the packaging container is semi-sealed leaving an air passage, and the packaging container is placed in a hot air atmosphere. A method for heating packaged food, which comprises heating food materials in a packaging container by irradiating far infrared rays in a wavelength range that is not absorbed by the plastic that constitutes the packaging container.