JPS62158677A - Microwave heated cooked food - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to microwave-cooked foods whose contents can be seen and which can be stored for long periods at room temperature, and in which a microwave-transparent transparent packaging material with particularly high oxygen gas and water vapor barrier properties is used. This invention relates to microwave-cooked foods. [Prior Art] Currently, in order to distribute sealed food packages at room temperature for a long period of time, food products are sterilized by the Ruto sterilization method. However, the sterilization method uses a heating medium of 100°C or higher to sterilize under pressure, but the temperature reached to the center is mainly due to heat conduction of the food, so the properties of the food (especially those containing solids) It takes an extremely long time, such as 15 to 60 minutes at 120°C, to satisfy the predetermined sterilization conditions for some foods. As a result, packaging materials and foods are exposed to high temperatures for 1 q. The packaging materials have to be of high quality and expensive, and the biggest drawback is that the texture, taste, color, etc. of the food are impaired. Although it is a point, the packaging material that is transparent and retains its contents is oxygen gas barrier A.
7- It was impossible to store food for a long time after sterilization due to its low quality. Therefore, these 1-1 sterilization methods require advanced technology to adjust the pressure to prevent the package from bursting, since sterilization is carried out under pressure. As an alternative to this retort sterilization method, a sterilization method using microwaves that can be heated in a short time has attracted attention, and a method of sterilization by irradiating microwaves under pressure, similar to the sterilization method, was studied by the United States Army. However, this method uses microwave irradiation under pressure, so like the retort sterilization method, it is difficult to adjust the pressure, and the sterilization equipment is complex and expensive, making it difficult to be used widely. Met. In addition, as a bacterial method using microwaves,
As shown in Japanese Patent No. 26949, a method has been proposed in which a package containing an object to be sterilized is sealed in a pressure-resistant container made of a material that can transmit microwaves, and the material is sterilized by irradiating it with microwaves from outside the pressure-resistant container. ing. According to this method,
Sterilization can be done by sealing the package in a pressure-resistant container and irradiating it with microwaves, but since the microwaves are irradiated all at once, uneven heating tends to occur, especially for foods with low moisture content. There were disadvantages such as a high occurrence of Furthermore, methods and equipment for continuous microwave sterilization under normal pressure have been proposed, but the equipment makes it difficult to use transparent, high-barrier packaging materials, making it difficult to obtain food packaging suitable for long-term storage. The current situation was that there was no such thing. [Object of the Invention and Problems to be Solved] An object of the present invention is to provide a microwave-cooked food whose contents can be seen and which can be stored at room temperature for a long period of time. In other words, it is a sealed microwave cooking method that uses continuous microwave irradiation under normal pressure to efficiently sterilize food without compromising its quality, and allows the contents to be seen and prevent quality deterioration during storage at room temperature. The aim is to produce processed foods. As a result, microwaves can be transmitted efficiently, there is no physical damage to the packaging material during the sterilization/cooling process, and the process of distributing the product at room temperature, and it is transparent and contains oxygen that does not cause changes in the composition of the food contents. It is a necessary condition that it is sealed with a packaging material that has barrier properties against water vapor. [Means to Solve the Problems] The present invention provides a heat-resistant synthetic resin film base material alone or a laminate product with a heat-sealable heat-resistant synthetic resin film as the innermost layer, and the intermediate layer thereof is made of Microwave transmission possible with a thin film of single oxide or mixture

A packaging bag, molded container, or can made of a transparent laminated packaging material is filled with food, the sealed package is stored in a support, and heated in a microwave irradiation oven at a temperature of 100°C or higher. By heating and sterilizing the food, we have created a microwave-cooked food that allows the contents to be seen and can be stored for long periods at room temperature, thus solving the problems of conventional products. [Function] Microwaves penetrate food to some extent and heat it directly from the inside, raising the core temperature of the food to 7°C in a short time. It is possible to be thirsty. At this time, by using a support that transmits microwaves ν1, it is possible to prevent the package from bursting due to water vapor pressure. In addition, by using a 1i4 thermal synthetic resin film/metal oxide thin film/heat-sealable heat-resistant synthetic resin film structure as a packaging material, it is transparent to microwaves, the contents can be seen, and it is easy to use when irradiated with microwaves or exposed to microwaves. There is no deterioration in gas barrier properties after irradiation, and food can be stored for long periods at room temperature. [Example] The present invention will be specifically described below. First, the packaging material according to the present invention will be explained. The packaging material of the present invention has heat resistance for high temperature sterilization, physical strength for normal pressure and high temperature sterilization, transparency for preserving contents, microwave transparency for microwave sterilization, and long-term storage at room temperature. Gas barrier properties such as oxygen and water vapor barrier properties are required at a minimum. Therefore, a laminated material made of the following materials and methods is required. That is, as a heat-resistant synthetic resin film base material, a single or laminated product of heat-resistant films such as polyester film, nylon film, and polypropylene film is used. In addition, as a heat-sealable heat-resistant film, heat-resistant polyolefin such as unstretched polypropylene is used as the innermost layer, and these films alone or polyester films,
Laminated products with heat-resistant films such as nylon film and polypropylene film, such as polyester film/
Unstretched polypropylene film laminates, stretched nylon film/unstretched polypropylene film laminates, stretched polypropylene films/unstretched polypropylene films, etc. are used. Next, the metal oxides provided in the intermediate layer between these base materials and the sealable film include titanium oxide, zinc oxide,
Aluminum oxide, silicon oxide, magnesium oxide, manganese oxide, and other microwave-transparent gold oxides can be used, but for practical purposes, aluminum oxide, silicon oxide, etc. are most suitable, and aluminum oxide/silicon oxide,
Mixtures, etc. are also right-handed. Further, the metal oxide thin film used in the present invention can be coated onto the surface of a synthetic resin film usually by a vacuum deposition method or a sputtering method, and the film thickness is preferably 500 to 1,000. Table 1 shows examples of deposited film thickness and barrier properties. Table-1 Table-1 shows silicon oxide thin film on polyester 25μ
This is an example of the barrier properties obtained using the vacuum evaporation method. The method of laminating these films is not particularly limited, but the adhesive strength can be improved by providing a modified polyolefin (for example, carboxyl group-containing polyolefin, etc.) layer between the heat-resistant sealing material layer and the metal oxide thin film layer. is publicly known. Next, the microphone D wave heating cooking method of the present invention will be explained. The present invention has heat resistance and barrier properties against oxygen and water vapor by providing a metal oxide thin film as described above in the intermediate layer,
A laminated material that also transmits microwaves is made into a bag shape, and the opening is filled with food, especially cooked food containing solids, and the opening is sealed leaving a vent hole in the opening. A storage section with a volume that can accommodate the food filling package and approximately the same shape is made of a material that can transmit microwaves, such as synthetic resins such as Teflon, polycarbonate, polyphenylene sulfide, and polyahital, and various ceramics. The sample was placed in a support, continuously placed in a first microwave irradiation oven, heated to around 100'C, and the ventilation holes were sealed, and then continuously placed in a second microwave irradiation oven. Pour it in, heat it to a predetermined temperature of over 100℃, and immediately cool the support.
It is a microwave-heated food that can be stored for a long period of time by removing the package and removing the specific gravity.Compared to conventional heat sterilization, the texture, taste, color, texture, etc. of the food are improved during sterilization. 19 cooked food products have been developed that have little loss and can be stored for long periods at room temperature. In the above method, primary heating was performed after filling the cooked food and sealing with a vent hole left in a part of the 11n opening. Micro-irradiation% 1 may be heated in an oven. In addition, the heating can be done not only in two times but also in one time using the micro-irradiation oven. It is also possible to sterilize more effectively by heating with .A molded container configured to use a container body made of deep-drawn laminated material in addition to the packaging body, and after filling with the contents, is sealed with the same laminated material, Cans whose body is made of laminated material and whose top and bottom are sealed with equipment can also be processed in the same way as described above to produce 1 q of cooked food that can be stored for a long time at room temperature. After that, the conventional method
After 11 heat sterilization by the sterilization method and the method of the present invention, respectively, immediately after heat sterilization and immediately after heat sterilization, and 6
The taste and sensory results of the finished product stored for several months are shown. Taste/sensory evaluation was conducted by 10 panelists regarding appearance, aroma, taste, changes in texture, presence or absence of off-odor, etc., and the results were expressed by scores and special notes. Relative comparisons were made with the best score for each food item being given a maximum of 5 points. The scoring criteria are as follows. 5.0...Best 4.0...Good 30...Commercial value limit 1.0 0...Not edible The outline of the conventional method and the present invention are as follows. Conventional method After cooking and processing each food, polyester (12 μ) / nylidene chloride (20 μ) / unstretched polypropylene (70 μ)
The mixture was filled and sealed in a pouch consisting of .mu.), and then left standing in hot water at 125.degree. C. for 1-route sterilization (including cooling time). For these b, immediately after retort sterilization and indoors (
After being allowed to stand for 6 months at 20-30°C, each sample was evaluated for taste and sensory evaluation. After cooking and processing each food of the present invention, polyester (25 μ) / silicon oxide (600 μ) / unstretched polypropylene (70 μ
) was filled into a pouch and sealed with some ventilation holes left, and the package at room temperature was irradiated for 3 minutes in a first microwave oven with an oscillation output of 3 kW, heated to 95°C, and then held for 3 minutes. The ventilation hole is sealed while the oscillation output is 1k1.
The sample was placed in the second microwave oven of No. 4, irradiated for 3 minutes, held at 125° C. for 6 minutes, and cooled for 3 minutes. As with the conventional method, these products were subjected to taste and sensory evaluation immediately after heat sterilization and after being left indoors (20 to 30°C) for 6 months. The amount filled in each package was 150 g. [Test Example 2] The conventional method was carried out in the same manner as Test Example 1, but the present invention was carried out as follows. After cooking and processing each food, polyester (25 μ) / silicon oxide (600 μ) / unstretched polypropylene (70 μ)
) Filled and sealed into a pouch, irradiated in a 4kW microwave oven while inverting the support together for 4 minutes, held at 125°C for 3 minutes, heated, and then cooled for 4 minutes.
Then, we performed heat sterilization. For these items, similar to the conventional method, immediately after heat sterilization and indoors (20
After being allowed to stand for 6 months at (~30°C), each sample was evaluated for taste and sensory evaluation. The foods tested are shown in Table 2.
1,2°3.8.9.10. As a result, both the conventional method and the present invention showed 1.2, 3, and 8.9 in Table 2.
The results were similar to those obtained with ゜10. [Test Example 3] In the conventional method, after cooking and processing white stew and boiled wild vegetables, a laminated material of unstretched ± iron film (20μ)/vinylidene chloride film (20μ)/unstretched polypropylene film (700μ) was vacuum-processed. Molded, 80X 100
A tray of x 20 mm (volume 160 cm3) was made, and a polyester film (25μ) was used as a lid material.
Using a laminated material consisting of / vinylidene chloride film (20μ) / unstretched polypropylene (50μ), 150g of each of the above foods was filled and packaged, and then heat sterilized using hot water at 125°C and a stationary retort device. Ta. Taste and sensory evaluation before and after sterilization were conducted in the same manner as in Test Example 1. In the present invention, the same food as in the conventional method is vacuum-formed from a laminated material of unstretched nylon film (20μ)/silicon oxide 1 (iooo)/unstretched polypropylene (700μ).
80 x 100 x 20 mm (volume 160 cm3
) were prepared, and using a laminated material r1 consisting of polyester film (25Il)/IA silicone (600 people)/unstretched polypropylene film (50μ) as the lid material, each food was filled and packaged with 150rJ each. , attached to the retainer in the same manner as in Test Example 1, irradiated with microwaves for 4 minutes in a microwave d-wave Δ-syn of 4, held for 3 minutes, cooled for 3 minutes, heat sterilized, and tasted in the same way.・
Sensory evaluation was performed. The results are shown in Table 3. [Test Example 4] After cooking or processing the following foods, they were heat sterilized by the conventional method and the present invention, respectively, and the taste and sensory results are shown immediately after heat sterilization and after storage for 6 months. The taste/sensory testing method and scoring criteria were the same as in Test Example 1. Conventional method After cooking and processing each food, a cup-shaped container d shown in FIG. It was sealed with a polypropylene single-layer film e, and then sterilized in hot water at 125° C. and in a stationary retort. For these items, immediately after retort sterilization and indoors (20~
After being naturally released at 30°C for 6 months, each sample was evaluated for taste and sensory evaluation. This invention: 60 μm of silicon oxide is added to a polyester film with a thickness of 25 μm.
0 person vacuum evaporation, apply 4.5g/m urethane adhesive to this evaporation surface, laminate 70μ unstretched polypropylene film, and further apply 4.5g/rIL urethane adhesive to the opposite side. A 30 μm unstretched polypropylene film was applied to prepare a laminated film J. This film was made into a spiral can body as shown in FIGS. 4 and 5. The can rhI has a shape as shown in FIG. 4 as an enlarged partial sectional view and as shown in FIG. 5 as an overall view with an enlarged cross section. That is, the 4-1 layer material J, which is used in the present invention and has a silicon oxide vapor deposited layer as an intermediate layer, is made of unstretched polypropylene tJ) with a thickness of 10μ from the inside, a urethane adhesive layer B of 45 U, and one layer of 600 Silicon oxide vapor deposited film layer C125μ
polyester layer D, 4.5g/TIt urethane adhesive layer B, 30μ unstretched polypropylene layer 1, and the outer layer material has a 200μ Unstretched polypropylene FME, 500
It consists of a polypropylene layer F of μ and a polypropylene layer G of 30 to 50 μ. 52.3 shown in Figure 6 by attaching a bottom lid made of injection-molded plastic laminate to this J: Eel Can Ina.
After making a container with a diameter of 90 mH and cooking each food C, it was filled with 160 ml of food, and a top lid made of the same plastic laminated material as the bottom lid was attached and sealed, and then integrated with the support in a microwave irradiation oven. Heat sterilization was performed by repeating the process of irradiating at output 4 for 14 minutes, holding for 2 minutes, irradiating for 2 minutes, and holding for 2 minutes while rotating or shaking the sample until a predetermined sterilization was achieved, followed by cooling. Taste and sensory evaluations were conducted on these products immediately after heat sterilization as in the conventional method and after being left indoors (20 to 30°C) for 6 months. The results are shown in Table 4. [Effects of the Invention] The microwave-cooked food of the present invention that can be stored for a long period of time has a shorter heating time than the conventional one-route sterilization, so the quality is good immediately after heat sterilization. Furthermore, by using transparent packaging with high oxygen gas barrier properties and A material, the contents can be seen, the high quality after heat sterilization can be maintained, and Nagato storage at room temperature is now possible.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an embodiment of the packaging material used for the microwave-heated food of the present invention, and FIG. 2 is a state in which the package is filled with the microwave-heated food of the present invention. 3 is a sectional explanatory diagram showing a case where a tray is used, FIG. 4 is an enlarged partial sectional view of a plastic can +14 which is an embodiment of the present invention, and FIG. 5 is a sectional explanatory diagram. Fig. 6 is a cross-sectional view of the color-shaped container of the present invention, and Fig. 7 is a cross-sectional view of a polypropylene single-layer container with a thickness of 300 μm used in the conventional method.・Polyester film 2...Silicon oxide thin film 3...Unstretched polypropylene film 4...Wrapping body 5...Contents 6...Tray
7... Lid △... Unstretched polypropylene layer B... Polyurethane adhesive layer C... Silicon oxide vapor deposited film layer D... Polyester layer E... 200μ unstretched polypropylene layer F...・5
00μ polypropylene layer G...30-50μ polypropylene layer 14...3
0 μ unstretched polypropylene layer J...Laminated material K having a silicon oxide vapor deposited film layer in the middle...Exterior material
a...can 1le 1b...'I
C... Contents Food Figure 1 Figure 2 Figure 6 Figure 5

Claims (2)

[Claims] (1) Heat-resistant synthetic resin film base material alone or a laminate with a heat-sealable heat-sealable heat-resistant synthetic resin film as the innermost layer and a metal oxide alone or a mixture thin film provided as an intermediate layer of the single or laminate to transmit microwaves. This microwave-cooked food, which can be stored for a long time and can be stored for a long time, is made by filling a package made of transparent laminated packaging material with the contents, then irradiating it with microwaves and heat-sterilizing it. (2) The microwave-cooked food that can be stored for a long time and has visible contents, as claimed in claim 1, wherein the metal oxide or mixture is a silicon oxide or a mixture.