JP2000102368A - Retort sterilization of solid food - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sterilize a retort of a solid food without deforming the shape of a container and a solid food, with a shortened sterilization time, and further without deteriorating the taste or the like due to the oxidation and browning of the solid food by sealing a heat resistant container holding the solid food in it by a specific method and subjecting the sealed container to a heating treatment. SOLUTION: A retort sterilization method for sterilizing a solid food in a heat resistant container. Water for keeping the inside of the heat resistant container in a moisten state during a heating treatment is placed together with gas in such a manner that the water does not come into contact with the solid food in the heat resistant container holding the solid food, and the container is sealed in this state and then subjected to a heating treatment. Here, it is preferable that the heat resistant container has a separating means for separating the added water from the solid food, i.e., material to be sterilized, and the whole of the inside of the heat resistant container is kept in a moisten state with the steam of the added water during the retort sterilization treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic retort sterilization method for solid foods. ADVANTAGE OF THE INVENTION According to the pneumatic retort sterilization method of this invention, while a heat processing time can be shortened, the quality deterioration of the solid foodstuff which arises at the time of a heat processing is suppressed.

[0002]

2. Description of the Related Art Conventionally, a constant-pressure retort sterilizer has been used for sterilizing liquid or solid foods. This constant-pressure retort sterilizer fills a tray or other container with food, seals it while containing air, and performs retort sterilization.When the air inside the container expands during the retort sterilization, the container is damaged. However, there was a problem that the retort was sterilized while containing air. For this reason, generally, retort sterilization treatment is performed by evacuating the inside of the container. However, when a retort pouch composed of a synthetic resin film or the like is used as a container for performing the retort sterilization treatment in a vacuum state, there is a problem that damage and deformation of the processed object having a shape cannot be avoided. is there.

[0003] As a retort sterilizer that has solved the problems of such a constant-pressure retort sterilizer, a constant-differential-pressure retort sterilizer has recently been developed. According to this constant pressure differential type retort sterilizer, even if the container contains gas, retort sterilization does not damage or deform the container. It is possible to prevent the deformation of the retort and to manufacture a retort sterilized product of which quality is maintained. For this reason, for example, rice dishes such as red rice or side dishes such as grilled fish and hijiki are filled in containers such as plastic trays,
Products that have undergone retort sterilization by sealing and packaging while containing air have come to market. Moreover, these products are highly convenient products that can be easily used by heating and cooking in a microwave oven or an oven, or the tray containers can be used as dishes as they are. Consumption of foods and prepared foods is increasing.

[0004]

The conventional retort sterilization method for solid foods using the above-mentioned constant-pressure retort sterilizer or constant-differential-pressure retort sterilizer involves immersion in a liquid (such as a seasoning liquid) and heat treatment. Is a general processing method. However, unlike the conventional retort-sterilized products, cooked rice and other prepared foods cannot be heat-treated by immersion in a liquid due to the characteristics of the product. There are products that have to be. If only solid food is retorted in a container containing air without being immersed in a liquid as described above, the heat transfer coefficient deteriorates, the processing time increases, the productivity decreases, and the roasted flavor is reduced. Problems that come out and become different from the original flavor,
Alternatively, problems such as discoloration due to oxidation or browning often occur. In response to the problem of oxidation and browning, air has been replaced with an inert gas such as nitrogen gas.However, even if this method can suppress oxidation and browning to some extent, it is insufficient. is there.

[0005] As described above, if the retort treatment is carried out with the air remaining in the container, there are problems such as a poor heat transfer coefficient and a reduced flavor. Therefore, in the retort sterilization method using a constant differential pressure type retort sterilizer, there is a problem. Also, processing is performed in a vacuum state using a retort pouch as a container. However, as in the case of a retort sterilization method using a constant-pressure retort sterilizer, a pinhole is generated in the container, solid food is deformed in the container, and wrinkles are formed on the surface of the container, as in the case of the retort sterilization method using a constant-pressure retort sterilizer. Therefore, it is inevitable that a problem such as deterioration in appearance occurs.

An object of the present invention is to reduce the sterilization time without deforming the shape of a container or a solid food by performing retort sterilization in an aerated state, and furthermore, it is possible to reduce the oxidation or browning of the solid food. An object of the present invention is to provide a method for retort sterilization of solid foods without deterioration of flavor and the like.

[0007]

Means for Solving the Problems The present inventors have studied a method for retort sterilization of solid foods using a constant pressure differential type retort sterilizer, and as a result, an appropriate amount of water is present together with gas in a container together with gas. In order to obtain new knowledge that heat treatment is performed in the state of being made and the inside of the container is made moist heat state, heat conductivity is increased, sterilization and cooking effects are enhanced, and breakage and deformation of solid food can be prevented. The present invention has been completed based on such findings. That is, the present invention provides the following technology required for retort sterilization of solid foods in order to solve the above problems. The retort sterilization method for a solid food according to the present invention is a retort sterilization method for sterilizing a solid food in a heat-resistant container, wherein the heat-resistant container is heat-treated together with gas in a heat-resistant container containing the solid food. The method is characterized in that a heat treatment is carried out by sealing in a state where an amount of water necessary for bringing the inside of the sex container into a moist heat state is arranged so as not to contact the solid food. The heat-resistant container of the present invention is a heat-resistant container for packaging for producing solid retort-sterilized food, and has an exterior portion capable of being heat-treated in a state in which at least solid food, gas and water are enclosed. And a separating means for separating the solid food and water is provided in the exterior part. Furthermore, the retort food package of the present invention is a retort food package obtained by packaging a solid retort sterilized food, wherein the heat-resistant container described above and at least a solid retort sterile sealed in the heat-resistant container are provided. It consists of food, gas, and condensed water,
It is characterized by being processed by the retort sterilization method described above. According to the present invention, since the solid food is heat-treated in a state in which water for making the inside of the container moist and hot, and gas coexist, heat sterilization to the solid food is enhanced, and effective sterilization and Cooking can be performed, and furthermore, it is possible to effectively prevent problems such as breakage and deformation of the solid food and deterioration of flavor due to oxidation and browning of the solid food.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The present invention relates to a retort sterilization method for solid foods using a constant pressure differential type retort sterilizer, and the solid foods to be subjected to the retort sterilization treatment include boiled beans, tofu, hijiki, shumai and the like. Upon retort sterilization of these solid foods, the container is filled with a solid food to be sterilized together with an appropriate amount of water so that the inside becomes moist and hot during the retort sterilization, sealed, and then subjected to retort sterilization. To be processed. In addition, the heat-resistant container used in this retort sterilization method has an outer portion having a structure capable of enclosing at least solid food, gas and water, and in the outer portion, for separating solid food and water. Is preferred. In addition, as the gas to be enclosed in the container, any gas can be used as long as a predetermined wet heat state and internal pressure can be obtained during the heat treatment and the gas is suitable for the purpose of manufacturing the retort-sterilized food. It is preferable to use air in consideration of the properties and the like, but nitrogen gas and the like can also be used from the viewpoint of preventing oxidation.

In the present invention, the retort sterilization treatment is
Heat treatment at 121 ° C. for 4 minutes (F
A further treatment including the value 4), which refers to sterilization in which all heat-resistant bacteria such as spore-forming bacteria are killed and sterilized, but the present invention does not kill all heat-resistant bacteria but foods. It also includes sterilization to make it hygienic.
The F value is a value (unit: minutes) obtained by converting the killing effect of microorganisms when a food is heated at a certain temperature for a certain time into a time when the food is heated at 121 ° C. Regarding the temperature and time of death by heating these microorganisms, and the mortality,
[Basics and application of retort food (published by Koshobo Co., Ltd. on June 10, 1995, pp. 73-78)].

[0010] In the retort sterilization treatment of the present invention, the amount of water to be filled together with the solid food (hereinafter referred to as added water) depends on the volume of the container, the water content originally contained in the food, or the food. Depends on the characteristics of the
In the case of a 200 ml container, about 1 g of water is necessary for the inside thereof to reach a saturated vapor pressure during the retort sterilization treatment. This added water is condensed when cooled after retort sterilization, but the foods targeted by the present invention are originally high in water content,
This level of water is not a problem. However, if the quality of the solid food is affected, install water-absorbing paper or a water-absorbing agent in the water storage section such as the bottom or side of the container so that the condensed water does not directly touch the solid food. Taking action can avoid quality problems.

In such a constant differential pressure type retort sterilization method, the pressure in the container is generated by the vapor pressure of water and the expansion of gas. However, when the retort sterilization process is performed only with solid food, moisture evaporates from the surface. Happens. When moisture evaporates from the surface of the solid food, the surface of the food becomes hot, which causes browning and a unique flavor. For this reason, in the present invention, the added water is put into the container together with the solid food, and the added water supplements the water vapor pressure in the container generated during the retort sterilization treatment. By adding the added water to the container together with the solid food in this manner, the atmosphere in the container becomes moist and hot during the retort sterilization treatment, so that the water in the container does not evaporate. Or, even if it evaporates, it is suppressed and very small. Therefore, it is possible to prevent browning and burning odor on the surface of the solid food.

[0012] Further, there is an effect that the retort sterilization time can be shortened by the presence of the added water. In other words, comparing the case where the solid food is immersed in a liquid such as a seasoning liquid and retort sterilized, and the case where the solid food is subjected to the retort sterilization only, the case where the solid food is subjected to the retort sterilization only with the solid food is better. Generally, the rate of temperature rise is slow and it takes a long time to obtain the same sterilization effect. However, by adding the added water to make the atmosphere in the container during the retort sterilization process moist and hot, the initial heating rate is increased, and the heat transfer coefficient is also increased, which is close to the state of being heated in the liquid. Become. For this reason, the retort sterilization method of the present invention shortens the processing time as compared with the case where retort sterilization is performed using only solid food, and at the same time, as described above, the quality (flavor, food, etc.) of the solid food. Sensation, prevention of reduction of nutrients, etc.).

As described above, the retort sterilization method for solid foods according to the present invention can be effectively used for solid foods that cannot be processed by immersion in a liquid such as a seasoning liquid. In particular, when put in a container such as a retort pouch and subjected to retort treatment in a vacuum state, it is effective for products whose commercial value is reduced due to shape loss. One example of a heat-resistant container that can be used for the retort sterilization treatment of the present invention is shown in FIGS.
(E) shows each. The heat-resistant container shown in FIG. 1 is a separating means for separating an exterior part 1 having a configuration capable of enclosing at least solid food, water and gas, an installation position 2 of the solid food, and an injection area 3 of added water. 4a to 4e. The separating means 4a to 4c have a partition structure. The separating means 4a is composed of a net-like disk-shaped member, and the separating means 4b is composed of a disk-shaped member provided with a large number of through holes. 1 is fixed at a position at a predetermined distance from the bottom of the inner wall. The separating means 4c has a structure in which a disc-shaped member is provided with a leg of a predetermined length for maintaining a distance from the bottom. The separating means 4d has a structure in which the bottom of the container is raised in a protruding manner and used as a spacer. Further, the separating means 4e is provided for the exterior part 1
It is made of an inner cylindrical member inserted and fixed therein, and sterilization is performed by arranging added water between the exterior part 1 and the inner cylindrical member. The separating means 4a to 4c may have a structure integrated with the exterior part 1 or may be configured to be detachable from the exterior part 1. As a constituent material of the exterior part 1 and the separating means 4a to 4c, if these members have mechanical strength, heat resistance, safety as a packaging material for food, and the like required at the time of heat treatment, particularly, Not limited. For example, a resin such as polypropylene can be used.

[0014]

The present invention will be described in detail with reference to examples, and the effects of the present invention will be clarified by showing comparative examples. (Example 1) 150 ml polypropylene cup (70 m in diameter)
m, a cylindrical container with a height of 44 mm), place a 20-mesh mesh partition at 2 cm from the bottom and place four radish cut into 2 cm squares at the top of the partition, and place it on the bottom
10 ml of water was added and sealed. The air in the container was replaced with nitrogen gas to prevent discoloration due to oxidation during packaging. This is a constant pressure differential type retort sterilizer (Ltd.)
A retort sterilization treatment was performed by heating under pressure at 120 ° C. so that the F value at the center of the radish became 10 using a product of Hisaka Seisakusho; Model RCS-40RTGN).

Comparative Example 1 On the other hand, the same 150 m was used as a control.
l The polypropylene cup is partitioned by a 20-mesh mesh partition at 2 cm from the bottom with 4 mesh radish cut out at the top of the partition, and water is not added to the bottom to seal. Packaged. The air in the container was replaced with nitrogen gas to prevent discoloration due to oxidation during packaging. This was subjected to retort sterilization by pressurizing and heating at 120 ° C. so that the F value at the center of the radish was 10, as in Example 1.

FIG. 2 shows the temperature history during sterilization in Comparative Example 1, and FIG. 3 shows the temperature history during sterilization in Example 1.
Are shown below. Table 1 shows the results of the heating time up to 100 ° C., at which the F value is integrated, and the heating time at 120 ° C. in the sterilization treatment of a 2 cm square radish. 2 and 3, broken lines indicate the retort temperature (temperature in the heating pot), broken lines indicate the temperature in the polypropylene container, solid lines indicate the temperature at the center of the solid food, and solid lines indicate the F value. .

[0017]

[Table 1]

As apparent from Table 1 and FIGS. 2 and 3, in Example 1, the heating rate was increased, and the heating time at 120 ° C. was shortened by 16 minutes as compared with Comparative Example 1. Was completed. The sensory evaluation of the roasted flavor generated by the heat treatment showed that
The product obtained in Example 1 had less roasted flavor peculiar to the retort-sterilized food and had a better flavor.

Example 2 A 144-ml polypropylene container (6 cm long × 6 cm wide × 4 cm high) was partitioned by a middle partition perforated at 1 cm from the bottom, and 10 ml was placed below the partition.
Was added, and four pieces of Shumai were arranged on the upper part and sealed and packaged. It should be noted that Shumai was prepared according to a conventional method after mixing the raw materials according to the recipe shown in Table 2.
The air in the container was replaced with nitrogen gas to prevent discoloration due to oxidation during packaging. Using the same constant pressure differential type retort sterilizing apparatus as used in Example 1, pressurizing and heating at 120 ° C. so that the F value of the central part of Shumai becomes 10, the retort sterilizing treatment was carried out. Sensory evaluation was performed.

[0020]

[Table 2]

Comparative Example 2 On the other hand, the same 14
4ml polypropylene container (length 6cm x width 6cm x height 4c)
m), a partition was provided with a middle partition perforated at a position 1 cm from the bottom, water was not added to the lower part of the partition, four pieces of Shumai were arranged on the upper part, and sealed and packaged. Incidentally, Shumai was prepared in the same manner as in Example 2, and the air in the container was replaced with nitrogen gas in order to prevent discoloration due to oxidation during packaging. 120 ° C so that the F value at the center of Shumai becomes 10
After heating under pressure to perform retort sterilization, sensory evaluation of flavor was performed.

As a result of the organoleptic evaluation of Example 2 and Comparative Example 2, the food treated according to the present invention had less odor peculiar to the retort-sterilized food, had a favorable texture as Shumai, and had a good flavor. It was good.

[0023]

According to the present invention, during the sterilization treatment of solid food, the added water is added together so that the inside of the container becomes moist and hot, and the heat is transferred by adding the added water. This has the effect of improving the rate and shortening the time required for the heat treatment of the solid food to be sterilized. Further, since the evaporation of water from the surface of the solid food during the sterilization treatment is suppressed, the browning of the obtained solid food and the roasted flavor peculiar to the retort sterilized food are suppressed, and the quality is improved. Is what you can do.

[Brief description of the drawings]

FIGS. 1A to 1E are views each showing an example of the structure of a packaging container used for the retort sterilization treatment of the present invention.

FIG. 2 is a diagram showing a temperature history at the time of retort sterilization of a solid food when only a solid food in Comparative Example 1 is put in a container.

FIG. 3 is a diagram showing a temperature history at the time of retort sterilization of a solid food in a case where added water is put in a container together with the solid food in Example 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exterior part 2 Solid food arrangement position 3 Addition water injection position 4a-4e Separation means

Claims (5)

[Claims] 1. A retort sterilization method for sterilizing a solid food in a heat-resistant container, wherein the heat-resistant container containing the solid food is placed in a moist heat state at the time of heat treatment together with gas. Retort sterilization of solid food, characterized in that the water is sealed and heat-treated in a state where the water is not in contact with the solid food. 2. The heat-resistant container has a separating means for separating water to be added and a solid food to be sterilized, and the entire inside of the heat-resistant container is heated by the added water vapor. The retort sterilization method according to claim 1, wherein the retort sterilization process is in a moist heat state. 3. A heat-resistant packaging container for producing a solid retort-sterilized food, which has an exterior part capable of being heat-treated in a state in which at least the solid food, gas and water are enclosed. A heat-resistant container, wherein a separating means for separating the solid food and water is arranged in the exterior part. 4. The heat-resistant container according to claim 3, wherein the separating means is a partition, a spacer or a partition. 5. A retort food package obtained by packaging a solid retort-sterilized food, wherein the heat-resistant container according to claim 3 or 4 and at least a solid retort-sterilized sealed in the heat-resistant container. Food and
A retort food package comprising a gas and condensed water, which is retort-sterilized by the method according to claim 1 or 2.