JPH06296478A - Production of hermetically sealed packaged food and microwave heating and pressurizing sterilizer - Google Patents

Abstract

PURPOSE:To provide a method for producing hermetically sealed and packaged foods in which the target sterilization temperature of the respective foods can rapidly be attained in a stable state without any heating unevenness for each food in the foods filled in a container having plural housing parts capable of housing the respective several kinds of foods different in their heating conditions. CONSTITUTION:Foods are passed through a transporting step (B) for feeding at least one hermetically sealed and packaged food package unit 14 onto a conveying line 6, a microwave irradiating step (C) for irradiating the food package 14 with microwaves from waveguides 8 installed on the conveying line 6 under pressurized conditions of 0.5-2.8kg/cm<2> pressure and increasing the temperature of the food 11 in the package 14 to 100-130 deg.C and a heat-treating step (D) for keeping the temperature under the pressurizing conditions for a prescribed time to produce a thermally sterilized or thermally cooked and sterilized food.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to continuously sterilizing at least one kind of food to be heated, which is hermetically packaged, or cooking and sterilizing, which can be stored at room temperature for a long time, and can be eaten by simple re-cooking. The present invention relates to a method of producing a hermetically sealed packaged food, and a microwave heating and pressure sterilizer that can be used in the method.

[0002]

2. Description of the Related Art Conventionally, steam, hot water, etc. have been used for heat sterilization of food to be heated which is hermetically sealed, and this is performed by satisfying a predetermined heating condition by heat conduction from the outside. It was

However, the means for simultaneously heat-sterilizing by heat conduction from the outside with the steam, hot water or the like is extremely inefficient in heat and cannot rapidly raise the temperature of the object to be heated, so the heat-sterilization is performed. The processing required a considerable amount of time and the quality was significantly deteriorated.

Therefore, the heating of food by microwave is devised, and the food to be heated can be directly heated from the inside by the irradiation of microwave, so that the thermal efficiency is extremely good and the temperature of the object to be heated can be controlled. It is possible to increase rapidly, and recently it has become very popular.

As described above, when microwaves are used for sterilizing foods, it is said that it is possible to obtain higher quality products than the conventional means for heat sterilizing with steam or hot water. The sterilization conditions, microwave heating and pressure sterilization equipment, etc. have been proposed (Japanese Patent Publication No. 60-58668 and Japanese Patent Publication No.
-58669, Japanese Patent Publication No. 61-9162, Japanese Patent Laid-Open No. 63-27188
See Publication No. 9 etc. ).

[0006]

However, in the heat sterilization using the microwave heating and pressure sterilizer as in the conventional example, a standing wave, a reflected wave and the like are mixed,
There was a problem that so-called uneven heating occurred when the temperature of food increased.

Further, since the microwave irradiation is performed from one waveguide, it is inevitable when raising the whole food to the target sterilization temperature when the respective parts of the food are not heated substantially uniformly. In some cases, an overheated portion is generated, which may cause a significant deterioration in quality.

Further, in the stage of maintaining the target sterilization temperature, the temperature of the food is not always kept constant by the control by microwave irradiation, and the quality is deteriorated by the partially overheated state which is continuously generated. There are cases.

Further, for example, in a case where two or more kinds of foods are stored in one container, heating conditions (sterilization value F ₀ ) such as sterilization temperature of each food are different, and therefore, it is possible to use one waveguide. Microwave irradiation requires the above-mentioned
Since it was necessary to match the heating conditions to the food with the higher F ₀ value, the other food became an excessive condition, and in many cases, the quality was remarkably deteriorated.

Similarly, each of the storage parts in one container having at least two storage parts capable of respectively storing two or more kinds of foods to be heated having different properties such as capacity, pH, viscosity and water activity are filled. However, even in the case of heat sterilization at the same time, it is necessary to match the heating conditions to the food on the side with the higher F ₀ value that is required, so the heating state between the storage parts will be significantly different, and quality deterioration will also occur. Was there.

In particular, in continuous processing steps in the case of supplying products on a commercial scale, heating in one food product or between different food products in both the temperature raising process and the heating temperature maintaining process of the food product. It is necessary to take measures to minimize the occurrence of unevenness.

Therefore, in the present invention, in view of the above problems,
In one type of food stored in a container having one storage portion, the temperature of the food is rapidly reached to a target sterilization temperature in a state where heating unevenness is extremely small in one food, and heating is performed. Even when a container having a single storage portion for several kinds of food under different conditions or a container having a plurality of storage portions capable of storing each food product is filled, a stable state without heating unevenness for each food product can be obtained. It is an object of the present invention to provide a method for producing a hermetically sealed food product capable of rapidly achieving the temperature of each food product to a target sterilization temperature, and a microwave heating and pressure sterilization device usable in the method. .

[0013]

The present invention takes the following technical means in order to achieve the above object.

That is, in the microwave heat and pressure sterilizer, the microwave irradiation device for heat and pressure sterilization, or heat cooking and sterilization of the heated food 11 filled and sealed in the microwave permeable package 12, Of the microwave permeable packaging body 12 having at least two storage portions 12a, 12b ... Each of which can store at least two kinds of food to be heated 11, 11 '... under a pressure condition of 2.8 kg / cm ^2. In each storage part 12a, 12b ...
A plurality of waveguides 8 and 8 are provided so that the microwaves are radiated with an appropriate microwave radiation output that raises the temperature of each of the foods 11, 11 ′ to 100 to 130 ° C. It is characterized by that.

Further, in the method for producing a hermetically sealed food, a packaging step A in which the food 11 to be heated is filled and sealed in the microwave permeable packaging body 12, and the hermetically packaged food packaging body 14 is placed on the conveying line 6. A transportation process B for supplying at least one unit,
Under the pressurizing condition of 0.5 to 2.8 kg / cm ² , the transfer line 6
Microwave irradiation step C of irradiating microwaves from the waveguide 8 provided above to raise the temperature of the food 11 in the package 14 to 100 to 130 ° C; And the relative humidity is 0 to 30% and the ambient temperature is 130 ° C or less in the dry heat heating atmosphere for a predetermined period of time.
It is characterized by producing a food that has been sterilized by heating under pressure or cooked and sterilized by heating.

[0016]

In the method for producing a hermetically sealed food according to the present invention, the food 11 to be heated is waveguided under a pressure condition of 0.5 to 2.8 kg / cm ^2.
By the microwave irradiation step C of irradiating microwaves from above, the temperature of the food can be rapidly raised to 100 to 130 ° C, and then the food to be heated is heated in a dry heat atmosphere with relative humidity of 0 to 30%. In the heat treatment step D in which 11 is maintained for a predetermined time, it is possible to maintain a dry heat heating atmosphere having an ambient temperature of 130 ° C. or less under the above-mentioned pressurizing condition. It can be stably maintained, and it is possible to manufacture a stable sealed packaged food without uneven heating.

Moreover, as one of the microwave heating and pressurizing sterilizers S used in the microwave irradiation step C, the waveguide 8 is installed in the upper and lower portions, and one of the waveguides 8'is provided. The distance between the heated food 11 is the same as the wavelength of the microwave, or shorter, and the distance between the other waveguide 8 and the heated food 11 is longer than the wavelength of the microwave. The microwave radiated from the waveguide 8 ′ installed at the short position is the central part of the food 11 and the microwave radiated from the waveguide 8 installed at the long position is the peripheral part of the food 11. Each can be heated, and it becomes possible to rapidly reach the target sterilization temperature of the food product with extremely little uneven heating.

Further, in the microwave irradiation step C, at least two kinds of food to be heated 11, 11 '... Are filled and sealed in the microwave permeable packaging body 12 having at least two storage portions 12a, 12b. In addition, a microwave heating processing is provided in which a plurality of waveguides 8, 8 ... Are provided on the carrier line 6 so that the microwaves are radiated from the waveguide 8 to each of the storage portions 12a, 12b. If it is a pressure sterilizer S, each storage unit 12
a, 12b… Each food to be heated is filled inside 1
By providing the waveguide 8 adapted to the heating conditions (sterilization value F ₀ ) such as the sterilization temperature of 1,11 '..., the heating unevenness between each food to be heated 11,11' ... is completely eliminated. It is possible to manufacture a stable sealed packaged food.

[0019]

Examples The present invention is an instant food that can be stored at room temperature for a long period of time and can be eaten by simple re-cooking,
While filling the heated food 11 such as a food for a microwave oven in the package 12, is a method of sterilizing by microwave, or a method of producing a sealed packaged food by cooking and sterilizing, as an example,
A microwave permeable packaging body 12 having one storage portion is filled with one type of heated food 11 (including pilaf, cooked rice, and other ingredients-containing food), and a waveguide 8 is provided at each of the upper and lower portions. The steps of manufacturing using the installed continuous microwave heating and pressure sterilizer S ₁ will be sequentially described along the manufacturing line with reference to the drawings.

As shown in FIG. 1, the continuous microwave heating and pressure sterilizing apparatus S ₁ includes a first pressure adjusting section 1, a microwave irradiating section 2, a dry heat heating section 3, and a cooling section 4. Further, a second pressure adjusting section 5 is continuously provided so that the transfer line 6 can pass between the respective sections.

Said continuous microwave heating and pressure sterilizer S ₁
Each of the parts (first pressure adjusting part 1, microwave irradiating part 2, dry heat heating part 3, cooling part 4, second pressure adjusting part 5) is provided with a pressure adjusting pipe 7, and The pressure can be adjusted freely.

The microwave irradiator 2 is provided with two upper waveguides 8 and two lower waveguides 8'on the upper side and the lower side of the carrier line 6, respectively. The distance between the irradiated object (the food 11 to be heated filled in the package 12) is longer than the wavelength of the microwave, and the lower waveguide 8 ′ has a distance between the irradiated object and the microwave. It is installed so that it is shorter than or equal to the wave wavelength. Incidentally, the number of the installed waveguides 8 and 8'is not limited to two as in the above-mentioned embodiment, but can be appropriately increased according to the size and number of the food 11 and the package 12.

A hot air circulating heater 9 is provided in the dry heat heating section 3 of the apparatus S ₁ , and a cooler 10 is provided in the cooling section 4.

When a sealed packaged food is produced using the continuous microwave heating and pressure sterilizer S ₁ constructed as described above, first, the uncooked or cooked heated food 11 is prepared.
Is filled in a microwave permeable packaging body 12 made of, for example, polypropylene, ethylene-vinyl alcohol copolymer or the like, and sealed with a lid body 13. The above is the packaging process A.

Next, at least one of the hermetically sealed food packages 14 is conveyed and supplied into the continuous microwave heating and pressure sterilizer S ₁ by using the conveyor 15 or the like. The above
This is Transport Process B.

Next, the pressurizing conditions are adjusted to 0.5 to 2.8 kg / cm ² in the first pressure adjusting unit 1 and the microwave irradiating unit 2, and the upper waveguide 8 and the lower waveguide 8 ' The microwave is further radiated to raise the internal temperature of the food package 14 which has been hermetically sealed to 110 to 130 ° C. The above is the microwave irradiation step C.

Next, the temperature in the dry heat heating section 3 is set to 0.
Relative humidity 0 to 30% under pressure of 5 to 2.8 kg / cm ² ,
The atmosphere temperature is adjusted to a dry heat heating atmosphere of 110 to 130 ° C. and the conditions are maintained for a predetermined time. The above is the heat treatment step D.

Thereafter, the food package 16 is cooled and pressure is adjusted by the cooling unit 4 and the second pressure adjusting unit 5. The above is the cooling processing step E.

In this way, the sterilization value F ₀ of the slowest heating point of the filled food 11 to be heated is adjusted to be 0.5 to 30.0, and heat and pressure sterilization or heat cooked and sterilized sealed The manufacture of the packaged food 17 is completed.

In installing the waveguide of the microwave heating and pressure sterilizing apparatus S ₁ in the microwave irradiation step C,
The distance between the upper waveguide 8 and the hermetically sealed food package 14 is longer than the microwave wavelength, while the distance between the lower waveguide 8'and the hermetically sealed food package 14 is the microwave wavelength. Making it shorter.

Therefore, the food in the package 14 is irradiated with microwaves from the lower waveguide 8'installed at the short position.
The central part of 11, and the peripheral part of the food 11 can be respectively heated by the microwave radiated from the upper waveguide 8 installed at the long position, and the inside of the food package 14 is rapidly The temperature can be raised to 110-130 ° C.

Further, in the heat treatment step D, the food package 14 is dry-heated under a pressure condition of 0.5 to 2.8 kg / cm ^2, a relative humidity of 0 to 30%, and an ambient temperature of 110 to 130 ° C. Since the food package is maintained in the heating atmosphere for a predetermined time, the internal temperature of the food package 14 can be stably maintained, and the food product having very little heating unevenness can be manufactured.

Next, two kinds of heated foods 11a and 11b (for example, curry roux and rice, meat sauce and spaghetti) are contained in one microwave permeable packaging body 12 having two housings 12a and 12b. Regarding the microwave irradiation step C for filling the 12a and 12b respectively, a pair of waveguides 8a and 8a 'are provided at the upper and lower portions so that the storage sections 12a and 12b are irradiated with microwaves under different conditions. The steps of manufacturing using the continuous microwave heating and pressure sterilization apparatus S ₂ provided with 8b and 8b ′ will be sequentially described with reference to the drawings along the manufacturing line.

As shown in FIG. 2, the continuous microwave heating and pressurizing sterilization apparatus S ₂ is similar to the apparatus S ₁ in that the first pressure adjusting section 1, the microwave irradiating section 2 and the dry heat heating section 3 are also provided. The cooling unit 4 and the second pressure adjusting unit 5 are continuously provided,
The transport line 6 can pass between the above-mentioned parts.

The continuous microwave heating and pressure sterilizer S ₂
Each of the parts (first pressure adjusting part 1, microwave irradiating part 2, dry heat heating part 3, cooling part 4, second pressure adjusting part 5) is provided with a pressure adjusting pipe 7, and The pressure can be adjusted freely.

The microwave irradiator 2 is provided with six upper waveguides 8 and six lower waveguides 8'on the upper side and the lower side of the carrier line 6, respectively. Half of the waveguide 8a heats the food 11a to be heated in the storage portion 12a from above, and the other half waveguide 8b heats the food 11b to be heated in the storage portion 12b from above. Of the lower waveguide 8 ', half of the waveguide 8a' heats the food 11a to be heated in the storage portion 12a from the bottom, and the other half of the waveguide 8b. 'Is installed so as to heat the food 11b to be heated in the storage portion 12b from below.

The number of the installed waveguides 8 and 8'is not limited to three as in the above embodiment, but the properties of the foods 11a, 11b ..., The required heating conditions (sterilization value F ₀ ), In addition, it is possible to appropriately increase or decrease according to the size and type of the package 12.

Further, as in the apparatus S ₁ , the hot air circulation type heater 9 is provided in the dry heat heating unit 3 and the cooling unit is also provided.
A cooler 10 is arranged at 4.

At least two storage parts 12a, 12b capable of respectively storing at least two kinds of foods 11a, 11b to be heated by using the continuous microwave heating and pressure sterilizer S ₂ configured as described above are provided. When producing a food that is hermetically sealed in the microwave permeable packaging body 12 that has, first, uncooked, or cooked food 11a, 11b, for example, polypropylene or ethylene-vinyl alcohol copolymer etc. The microwave permeable packaging body 12 having at least two storage portions 12a, 12b consisting of the above is filled and sealed with the lid body 13. The above is the packaging process A.

Next, at least one of the hermetically packaged food packages 14 is conveyed and supplied into the continuous microwave heating and pressure sterilizer S ₂ by using the conveyor 15 or the like. The above
This is Transport Process B.

Next, the pressurizing conditions are adjusted to 0.5 to 2.8 kg / cm ² by the first pressure adjusting unit 1 and the microwave irradiating unit 2, and the upper waveguides 8a, 8b and the lower waveguides are adjusted. 8a ', 8b' irradiate microwaves to seal the food package 14
The internal temperature of each food 11a, 11b in the
Raise to 0 ° C. The above is the microwave irradiation process
Let's call it C.

Next, the temperature in the dry heat heating unit 3 is set to 0.
Relative humidity 0 to 30% under pressure of 5 to 2.8 kg / cm ² ,
Adjust to an atmosphere temperature of 130 ° C or less under dry heat.
The conditions are maintained for a predetermined time. The above is the heat treatment step D
And

Thereafter, the food package 16 is cooled and pressure adjusted by the cooling unit 4 and the second pressure adjusting unit 5. The above is the cooling processing step E.

In this way, the sterilization value F _{0 at} the slowest heating point of the filled foods 11a, 11b to be heated is 0.5 to 30.0, respectively.
The heat-pressurized sterilization, or the heat-cooked and sterilized hermetically sealed packaged food 17 is completed.

When installing the waveguide of the microwave heating and pressure sterilizing apparatus S ₂ in the microwave irradiation step C,
The distance between the upper waveguide 8 and the hermetically sealed food package 14 is longer than the microwave wavelength, while the distance between the lower waveguide 8'and the hermetically sealed food package 14 is the microwave wavelength. May be shorter.

As described above, the microwaves radiated from the two types of upper waveguides 8a and 8b having different microwave radiation outputs are applied to the peripheral portions of the foods 11a and 11b to be heated in the package 14, respectively.
Further, the central portion of the food 11a, 11b can be respectively heated by the microwaves radiated from the lower waveguide 8a ', 8b', and the internal temperature of the food package 14 is rapidly increased. It can be raised to 100-130 ° C.

Further, in the heat treatment step D, the food package 14 is dry-heated under a pressurized condition of 0.5 to 2.8 kg / cm ^2, a relative humidity of 0 to 30% and an ambient temperature of 130 ° C. or less. Since the food package 14 is kept in the atmosphere for a predetermined time, the internal temperature of the hermetically sealed food package 14 can be stably maintained.

Specific examples of the method for producing the sealed packaged food 17 of the present invention will be described below with reference to experimental examples.

<< Experimental Example Using Microwave Heating and Pressurizing Sterilizer S ₁ >><FirstExample> First, as a packaging step A, 360 g of extremely high-viscosity potage soup was made of polypropylene having a capacity of 600 ml and a microwave permeable packaging. After filling the body 12, a lid 13 made of plastic is hermetically sealed.

Next, after the carrying step B, as the microwave irradiation step C, the pressure inside the hermetically sealed package 14 is adjusted to 2.1 kg / cm ² in the microwave irradiation section 2 and the microwave irradiation is performed. Microwaves are irradiated for a predetermined time from the upper waveguide 8 having an irradiation output of 0.5 kw and the lower waveguide 8 ′ having a microwave irradiation output of 1.0 kw.

Next, as a heat treatment step D, a dry heat heating section is used.
Adjust the pressure in 3 to 2.1 kg / cm ² , the ambient temperature to 122 ° C, and the dry humidity heating atmosphere with relative humidity of 0%, and maintain for a predetermined time.

During the above-mentioned steps, the package 12
The change in the product temperature of the peripheral portion and the central portion of the potage soup inside was measured. The result is shown in FIG. As is clear from the above measurement results, almost no temperature difference was observed in the peripheral portion and the central portion of the potage soup, and heating unevenness was hardly generated as a whole, and discoloration or the like did not occur in terms of quality. .

<First Comparative Example> After the packaging step A, the transportation step B and the pressurizing condition in the microwave irradiation step C were similarly adjusted as in the first embodiment, the microwave irradiation output was adjusted.
Microwaves were radiated only from the upper waveguide 8 having a thickness of 0.7 kw, and the same production was performed thereafter.

During the progress of each of the above steps, the package 12
The change in the product temperature of the peripheral portion and the central portion of the potage soup inside was measured. The result is shown in FIG. As is clear from the above measurement results, an excessive temperature difference was observed in the peripheral portion and the central portion of the potage soup, and the resulting potage soup caused a remarkable browning, especially in the peripheral portion, which was a completely commercial product. It became worthless.

<Second Comparative Example> After the packaging step A, the transportation step B, and the pressurizing condition in the microwave irradiation step C were similarly adjusted as in the first embodiment, the microwave irradiation output was adjusted.
Microwaves were radiated only from the lower waveguide 8'having 1.2 kw, and the same production was performed thereafter.

During the respective steps as described above, the package 12
The change in the product temperature of the peripheral portion and the central portion of the potage soup inside was measured. The result is shown in FIG. As is clear from the above measurement results, an excessive temperature difference was observed in the peripheral portion and the central portion of the potage soup, and the resulting potage soup caused a remarkable browning especially in the central portion, which was a completely commercial product. It became worthless.

<Third Comparative Example> After the packaging step A, the transportation step B and the pressurizing condition in the microwave irradiation step C were adjusted in the same manner as in the first embodiment, the microwave irradiation output was changed.
The upper waveguide 8 with 0.5kw and the microwave irradiation output is 1.
Microwaves are radiated from the lower waveguide 8 ′ at 0kw for a predetermined time respectively, and then the microwave radiation output from the upper waveguide 8 is 0.1kw and the microwave radiation output from the lower waveguide 8 ′ is changed. The microwave irradiation step C was repeated by continuously starting and stopping the microwave irradiation for a predetermined time at 0.2 kw, and thereafter, the heating treatment step D was not performed and the production was performed.

During the respective steps as described above, the package 12
The change in the product temperature of the peripheral portion and the central portion of the potage soup inside was measured. The result is shown in FIG. As is clear from the above measurement results, the product temperature was not stable at the microwave irradiation stage, and the resulting potage soup also browned, which seems to be due to overheating, and had no commercial value. became.

<< Experimental Example Using Microwave Heating and Pressurizing Sterilizer S ₂ >><FirstExample> First, as a packaging step A, two storage portions, a storage portion 12 a having a capacity of 350 ml and a storage portion 12 b having a capacity of 250 ml, are stored. One of the pre-molded, one-piece polypropylene containers is filled with 115 g of washed and dipped rice and 85 g of water (rice cooked part) in the one storage part 12a (350 ml side), and the other storage part 12
After filling the b (volume 250 ml side) with a total of 185 g (curry portion) of the curry roux that has been melted by heating, the meat that has been heat-treated, potatoes and carrot, a plastic lid 13 is used to perform a hermetic seal.

Next, after the carrying step B, as a microwave irradiation step C, the pressure inside the hermetically sealed package 14 is adjusted to 2.1 kg / cm ² in the microwave irradiation section 2 and the capacity is 350 m.
The microwave irradiation output of the upper waveguide 8a and the lower waveguide 8a 'installed to heat the cooked rice portion 11a on the l side was 0.12kw, while the curry portion 11b on the 250ml side was filled. The microwave irradiation outputs of the upper waveguide 8b and the lower waveguide 8b 'installed for heating the are adjusted to 0.3 kw, respectively, and passed through within a predetermined time.

Next, as a heat treatment step D, a dry heat heating unit is used.
Adjust the internal pressure to 2.1 kg / cm ² , the ambient temperature to 121 ° C, and the relative humidity to 0% in a dry heat heating atmosphere, and maintain it for a predetermined time.

During the progress of each of the above steps, the package 12
About the center of each of the cooked rice and curry (the slowest heating point)
The change in product temperature was measured. The result is shown in FIG. As is clear from the above measurement results, the product temperature at the slowest heating point of the curry portion reached about 120 ° C in the microwave irradiation step C, and the heat treatment portion D already maintained a substantially constant product temperature. The product temperature of the slowest heating point of the cooked rice part is almost
The temperature reached 102 ° C. and gradually increased even in the heat-treated part D, reaching 120 ° C. in the final part of the heat-treated part D, and the obtained cooked rice and curry had good quality. still,
Sterilization value when the F ₀ is curry section F ₀ = 12.5, the rice section is F ₀ =
It was 5.2.

<Second Embodiment> One storage portion 12a (capacity 35
(0 ml side) was filled with cooked rice as in the first embodiment, and the other storage 12b (capacity 250 ml side) was filled with 180 g (hayashi) of demiglace sauce and seasoned meat, potatoes and onions in total. Similarly, a lid 13 made of plastic is integrally hermetically sealed.

Next, after the carrying step B, as a microwave irradiation step C, the pressure inside the hermetically sealed package 14 is adjusted to 2.1 kg / cm ² in the microwave irradiation section 2 and the capacity is 350 m.
The microwave irradiation output of the upper waveguide 8a and the lower waveguide 8a 'installed to heat the cooked rice portion 11a charged to the l side was 0.12 kw, while the hayashi portion charged to the 250 ml side was The microwave irradiation outputs of the upper waveguide 8b and the lower waveguide 8b 'installed to heat 11b are adjusted to 0.25 kw, respectively, and they are passed within a predetermined time.

Next, as the heat treatment step D, a dry heat heating unit is used.
Adjust the internal pressure to 2.1 kg / cm ² , the ambient temperature to 121 ° C, and the relative humidity to 0% in a dry heat heating atmosphere, and maintain it for a predetermined time.

During the respective steps as described above, the package 12
About the center of each of the rice and Hayashi parts (the slowest heating point)
Was measured (not shown). From the measurement results, the product temperature at the slowest heating point of the hayashi portion reached about 120 ° C in the microwave irradiation step C, and the heat treatment portion D already maintained a substantially constant product temperature. The product temperature at the slowest heating point reaches approximately 102 ° C in the microwave irradiation step C, further gradually rises in the heat treatment part D, and reaches approximately 120 ° C in the final part of the heat treatment part D, and The resulting cooked rice and hayashi had good quality. The sterilization value F _{0 at} this time was F ₀ = 11.5 for the hayashi part and F ₀ = 5.8 for the cooked rice part.

<First Comparative Example> After the packaging step A and the transportation step B in the first example, the conventional retort sterilization using hot water was performed instead of the microwave irradiation, and the product temperature change was similarly performed. The measurement, and further the ambient temperature was measured. The result is shown in FIG.

As is clear from the above measurement results, after the atmospheric temperature reaches 120 ° C, the cooked rice portion reaches 120 ° C, and then the curry portion reaches 120 ° C. It was brown and had no commercial value. The sterilization value F _{0 at} this time was F ₀ = 12.3 for the curry portion and F ₀ = 22.3 for the cooked rice portion.

<Second Comparative Example> After the packaging step A and the transportation step B in the second example, the conventional retort sterilization using hot water was performed in place of microwave irradiation, and the product temperature change was similarly performed. The measurement, and further the ambient temperature were measured (not shown).

From the above measurement results, the ambient temperature was 120 ° C.
After the temperature reached, the cooked rice portion reached 120 ° C, and then the hayashi portion reached 120 ° C, so that the cooked rice portion remarkably browned and had no commercial value. The sterilization value F _{0 at} this time was F ₀ = 11. ₂ for the hayashi part and F ₀ = 20.6 for the cooked rice part.

[0071]

EFFECT OF THE INVENTION In the method for producing a hermetically sealed packaged food according to the present invention, a packaging step, a transportation step, and a microwave irradiation step are performed on a transportation line under a pressurized condition of 0.5 to 2.8 kg / cm ^2. Microwaves are radiated from the provided waveguide to rapidly raise the temperature of the food to 100 to 130 ° C, and further, in the heat treatment step, the temperature is kept under the pressure condition and the relative humidity is 0 ~.
Heat-pressurized sterilization that maintains a stable product temperature without heating unevenness by maintaining it in a dry-heated atmosphere with an ambient temperature of 130 ° C or less for 30%, or for cooked and sterilized sealed packaged food It becomes possible to manufacture.

In the microwave irradiation step,
Waveguides are provided on the upper and lower parts, and the distance between one of the waveguides and the food to be heated is equal to or shorter than the wavelength of the microwave, and the distance between the other waveguide and the food to be heated is When using a microwave heating and pressure sterilizer that is arranged to be longer than the wavelength of microwaves, the irradiation conditions of microwaves on foods will be partially different, and heating unevenness as a whole will be extremely high. It is possible to rapidly reach the target sterilization temperature of the food in a small amount.

Furthermore, in the microwave irradiation step,
At least two kinds of food to be heated are filled and sealed in a microwave permeable packaging body having at least two storage portions, and the storage line is irradiated with microwaves from the waveguide. When using a microwave heating and pressure sterilizer having a plurality of waveguides provided above, for each storage unit, heating conditions such as the sterilization temperature of the food to be heated filled therein ( By providing a waveguide adapted to the sterilization value F ₀ ), heating unevenness between the foods to be heated is completely eliminated, and in any case, very stable sealed packaged foods can be produced.

As described above, the method for producing a hermetically sealed packaged food and the microwave heating / pressurizing sterilizer according to the present invention can be used as a whole in one food for one kind of food stored in a container having one storage. It is possible to rapidly achieve the target sterilization temperature of the food in a state where the heating unevenness is extremely small, and a container having one storage portion for several kinds of foods having different heating conditions, Alternatively, even in the case of filling each container with a plurality of storage parts capable of storing each food, the temperature of each food is rapidly increased to the target sterilization temperature in a stable state without heating unevenness for each food. It is fully possible to achieve it.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a manufacturing process of a hermetically sealed packaged food and a microwave heating / pressurizing sterilizer of the present invention.

FIG. 2 is an explanatory view showing another manufacturing process of the hermetically sealed food according to the present invention and a microwave heating / pressurizing sterilizer.

FIG. 3 is a graph showing changes in internal component temperature in the first embodiment using the microwave heating and pressure sterilizer S ₁ .

FIG. 4 is a graph showing a change in internal component temperature of the first comparative example.

FIG. 5 is a graph showing a change in internal component temperature of the second comparative example.

FIG. 6 is a graph showing changes in internal component temperature of the third comparative example.

FIG. 7 is a graph showing changes in internal component temperature in the first embodiment using the microwave heating and pressure sterilizer S ₂ .

FIG. 8 is a graph showing changes in internal component temperature of the first comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st pressure adjustment part 2 Microwave irradiation part 3 Dry heat heating part 4 Cooling part 5 2nd pressure adjustment part 6 Conveyance line 7 Pressure adjustment pipe 8 Upper waveguide 8a Upper waveguide 8b Upper waveguide 8 'Lower waveguide 8a' Lower waveguide 8b'Lower waveguide 11 Heated food 11a Heated food 11b Heated food 12 Microwave permeable package 12a Storage part 12b Storage part A Packaging process B Conveying process C Micro Wave irradiation process D Heat treatment process

Claims (5)

[Claims] 1. A packaging step (A) for filling and sealing a heated food (11) in a microwave permeable packaging body (12) and a food packaging body (14) which has been hermetically packaged on a conveying line (6). In the carrying step (B) of supplying at least one to the above, and under the pressurizing condition of 0.5 to 2.8 kg / cm ² , microwave is radiated from the waveguide (8) provided on the carrying line (6). Then, the microwave irradiation step for raising the temperature of the food (11) in the package (14) to 100 to 130 ° C.
(C), the temperature under the pressure conditions, and relative humidity 0
Characterized by producing heat-pressurized or heat-cooked and sterilized foods through a heat treatment step (D) in which a dry heat heating atmosphere of ~ 30% and an ambient temperature of 130 ° C or less is maintained for a predetermined time. A method for producing a hermetically sealed food product. 2. The waveguide (8) in the microwave irradiation step (C) comprises upper and lower waveguides (8), (8 '),
The distance between one waveguide (8 ') and the food to be heated (11) is equal to or shorter than the wavelength of the microwave, and the other waveguide (8) and the food to be heated (11). The method for producing a hermetically sealed food according to claim 1, characterized in that the interval between the food and the food is longer than the wavelength of the microwave. 3. At least two kinds of food to be heated (11), (1
1 ') ... is filled and sealed in a microwave permeable packaging body (12) having at least two storage parts (12a), (12b).
In addition, a plurality of waveguides (8), (8) are provided on the carrier line (6) so that the microwaves are radiated from the waveguide (8) to the storage parts (12a), (12b). ) ... is provided, The manufacturing method of the sealed packaging foodstuff of Claim 1 or Claim 2 characterized by the above-mentioned. 4. A microwave irradiator for sterilizing a food to be heated (11) filled and sealed in a microwave permeable package (12) by heating, pressurizing, cooking and sterilizing.
At least two kinds of food to be heated under the pressure condition of cm ^2.
(11), (11 ') ... at least two storage parts capable of storing respectively
(12a), (12b) ... In the respective storage parts (12a), (12b) of the microwave permeable packaging body (12), the foods (11), (11 ')
Microwave heating provided with a plurality of waveguides (8), (8) so that microwaves are radiated with an appropriate microwave radiation output that raises the temperature of 100 to 130 ° C. Pressure sterilizer. 5. The waveguide (8) is composed of upper and lower waveguides (8), (8 '), one waveguide (8') and one kind of food to be heated (11). ) Is the same as or shorter than the wavelength of the microwave, and the distance between the other waveguide (8) and the food to be heated (11) is longer than the wavelength of the microwave. The microwave heating and pressure sterilizing apparatus according to claim 4.