Production method for koji two-stage aging

Abstract

To provide a production method for retort brown rice with a chewy texture obtained by using Koji and making two-stage aging.SOLUTION: A production method for retort brown rice (production method for Koji two-stage aging) according to the present invention at least executes the steps of: producing a retort container containing food materials by sealing brown rice, water, Koji, and air in the retort container; performing aging of a first stage of the brown rice by placing the retort container containing food materials in the temperature environment of 0-5 degrees for 12 to 60 hours; cooking the brown rice by placing the retort container containing food materials in a high-temperature and high-pressure cooker after the aging of the first stage; and performing aging of a second stage of the brown rice by placing the retort container containing food materials in the temperature environment of 10 degrees or higher for 12 hours or longer after the cooking.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for producing retort brown rice that uses koji and undergoes two-stage aging to obtain a chewy texture.

Background Art

[0002] Conventionally, brown rice sealed in a pack is allowed to stand in a germination environment of brown rice in which the temperature exceeds 0°C and is less than 10°C and the treatment time exceeds 3 days, and then the pack is transferred to a heating environment to cook the brown rice in the pack. A method for producing brown rice rice in a sealed pack is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above production method, it is claimed that brown rice rice with excellent umami and high nutritional value can be produced, but no attention has been paid to improving the texture of brown rice, which tends to be soggy.

[0005] Therefore, an object of the present invention is to provide a method for producing retort brown rice that uses koji and undergoes two-stage aging to obtain a chewy texture.

Means for Solving the Problems

[0006] The present invention provides a koji two-stage aging preparation method, which comprises at least the steps of: sealing brown rice, water, koji, and air in a retort container to produce a retort container containing ingredients; placing the retort container containing ingredients in a temperature environment of 0-5 degrees for 12-60 hours to perform the first-stage aging of the brown rice; after the completion of the first-stage aging, placing the retort container containing ingredients in a high-temperature and high-pressure cooker to cook the brown rice; and after the completion of the cooking, placing the retort container containing ingredients in a temperature environment of 10 degrees or more for 12 hours or more to perform the second-stage aging of the brown rice.

[0007] Also, in the step of performing the second-stage aging, it is preferable to blow air toward the surface of the retort container containing ingredients to lower the surface temperature of the retort container containing ingredients to the range of 10-25 degrees, and then place the retort container containing ingredients in a temperature environment of 10 degrees or more for 12 hours or more.

[0008] Also, in the step of performing the second-stage aging, it is preferable to blow air toward the surface of the retort container containing ingredients to lower the surface temperature of the retort container containing ingredients to the range of 15-20 degrees, and then place the retort container containing ingredients in a temperature environment of 10 degrees or more for 12 hours or more.

[0009] Also, the weight of the water sealed in the retort container is preferably 133.3-222.2% of the weight of the brown rice.

Effects of the Invention

[0010] According to the koji two-stage aging preparation method of the present invention, by using koji and performing two-stage aging, it is possible to produce retort brown rice with a chewy texture.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1-8.

[0013] The present invention relates to a method for producing retort brown rice (koji two-stage aging preparation method) capable of obtaining a chewy texture by performing fermentation with koji and two-stage aging. In the present invention, at least, a step of sealing brown rice, water, koji, and air in a retort container to produce a retort container containing food ingredients, a step of aging the first stage of brown rice by placing the retort container containing food ingredients in a temperature environment of 0-5 degrees for 12-60 hours, a step of cooking the brown rice by placing the retort container containing food ingredients in a high-temperature and high-pressure cooker after the end of the first-stage aging, and a step of aging the second stage of brown rice by placing the retort container containing food ingredients in a temperature environment of 10 degrees or more for 12 hours or more are performed.

[0014] As the brown rice used in the present invention, commercially available brown rice (including germinated brown rice) is used. In the present invention, washed brown rice (polished brown rice) is used, but unwashed brown rice (unpolished brown rice) may also be used. The rice washing may be performed by a known method. For example, it is conceivable to perform the rice washing in water at normal temperature for about 1 to 5 minutes.

[0015] The amount of brown rice is preferably 24 - 33% of the total weight of the food ingredients sealed in the retort container.

[0016] As the water used in the present invention, tap water filtered with activated carbon is used, but mineral water, hot water, or tap water used as it is may also be acceptable.

[0017] The amount of water is preferably 40.0 - 66.6% of the total weight of the food ingredients sealed in the retort container, and particularly preferably 46.6 - 60.0%. Also, the amount of water is preferably 133.3 - 222.2% of the weight of the brown rice, and particularly preferably 155.6 - 200.0%. In the present invention, the specific gravity of water is regarded as 1.0.

[0018] As the koji used in the present invention, koji obtained by inoculating steamed white rice with koji mold and allowing it to grow and ferment is used. As the koji, salted koji obtained by further adding salt may also be used.

[0019] The amount of koji is preferably 1 - 3% of the total weight of the food ingredients sealed in the retort container.

[0020] When using salted koji, the weight of the salt contained in the salted koji is preferably about 30 - 40 g per 100 g of the rice koji, and the weight of the water contained in the salted koji is preferably about 100 - 140 g per 100 g of the rice koji.

[0021] The retort container used in the present invention can be used for retort cooking in a high-temperature and high-pressure cooker in a state where the above food ingredients are sealed. For example, a flexible container such as a retort pouch can be considered.

[0022] In the present invention, the cooked rice of brown rice in the retort container is cooked by placing the retort container in a high-temperature and high-pressure cooker (high-temperature and high-pressure environment). However, if steam is not released during the cooking of the rice, the container may burst. Therefore, in the present invention, a retort container with an automatic steam ventilation function in which a vent hole is opened when the internal pressure rises is used. As the retort container with an automatic steam ventilation function, a known one may be used. For example, it is conceivable to use a retort pouch with a steam vent disclosed in JP-A-2006-151411.

[0023] The air used in the present invention is necessary to cause a decomposition action on the enzymes contained in brown rice and koji, and an amount that results in a degree of vacuum of about 60 - 80% in the state where the above ingredients are sealed is enclosed.

[0024] In the present invention, in addition to the above ingredients, adzuki beans may be enclosed in the retort container. As the adzuki beans used in the present invention, those in a raw bean state are used, but those after being boiled may also be used.

[0025] The amount of adzuki beans is preferably 1 - 3% of the total weight of the ingredients sealed in the retort container.

[0026] Subsequently, with reference to FIG. 1, the procedure of the method for producing retort brown rice (koji two-stage aging preparation method) according to the present invention will be described.

[0027] First, brown rice, water, koji, and air are sealed in a retort container to produce a retort container containing ingredients (S1). In this step, each of the above-mentioned ingredients in the above-mentioned amounts is sealed. Note that, as long as the object of the present invention and the effects obtained by the present invention are not inhibited, in addition to the above ingredients, other ingredients such as the above-mentioned adzuki beans and seasonings may be added.

[0028] Subsequently, the retort container containing the ingredients is placed in a temperature environment of 0-5°C for 12-60 hours to perform the first-stage aging of the brown rice (S2). In this step, the aging does not progress below 0°C, and there is concern that Escherichia coli will multiply above 5°C, so the retort container containing the ingredients is placed in a temperature environment of 0-5°C. In particular, from the perspective of preventing the growth of Escherichia coli, it is more preferable to place it in a temperature environment of 0-4°C for about 48 hours.

[0029] In addition, as long as the koji is a common one, even if the ingredients are slightly different, the temperature and time required for aging (bacterial growth) are almost the same, so the process can be carried out at the above temperature and time.

[0030] Subsequently, the retort container containing the ingredients is placed in a high-temperature and high-pressure cooker to cook the brown rice (S3). The retort treatment at high temperature and high pressure is for sterilizing harmful bacteria in the retort container in addition to cooking the ingredients. For this purpose, it is necessary to perform pressure heating treatment at a temperature environment of 120-130°C and a pressure environment of 0.20-0.25 Mpa for 7-10 minutes, so this is carried out.

[0031] Note that the enzymes (α-amylase and pro-tease) contained in the koji will lose their function when heated. However, in the present invention, since they are soaked in the ingredients and the like for a long time in S2 before cooking, the umami and good texture of the brown rice are extracted by α-amylase and pro-tease at that time, and the effect is maintained even after cooking.

[0032] After the cooking is completed, the retort container containing the ingredients is placed in a temperature environment of 10°C or higher for 12 hours or more to perform the second-stage aging of the brown rice (S4). In particular, in this step, it is preferable to place it in a temperature environment of 10°C or higher for 24 hours or more.

[0033] Here, brown rice often becomes a soggy texture after cooking. Therefore, usually, when cooking rice, water with a weight of about 110% of the weight of the brown rice is added. In the present invention, in S1, water with a weight of about 133.3 - 222.2% of the weight of the brown rice is added, so that a large amount of water remains in the retort container with ingredients even after cooking. Then, in S4, the remaining water is absorbed by the brown rice over 12 hours or more, thereby realizing a good texture.

[0034] Note that if the brown rice is left at a low temperature, it will harden. Therefore, in the present invention, in S4, it is left in a temperature environment of 10 degrees or more. However, since a particularly high temperature environment (such as heating) is not required here, it may be left within the room temperature range (about 10 - 35 degrees).

[0035] Furthermore, before the process of S4, after the cooking is completed, it is preferable to lower the surface temperature of the retort container with ingredients to the range of 10 - 25 degrees by blowing air toward the surface of the retort container with ingredients. In particular, it is preferable to lower it to the range of 15 - 20 degrees. For blowing air, a blower such as a circulator can be used. The blowing air may be performed only on one side of the sealed retort container. In that case, it is preferable to use a retort container with a small thickness such as a retort pouch.

[0036] Finally, in S4, after 12 hours or more have passed, the retort brown rice produced by the koji two - stage aging preparation method of the present invention is completed.

[0037] The brown rice produced as described above may be eaten after heating with a microwave oven or the like, like ordinary retort foods, or may be eaten without heating.

[0038] And the brown rice produced as described above will have a chewy texture due to the "fermentation by koji", "first-stage aging at low temperature", and "second-stage aging at room temperature". Specifically, the "action of enzymes" is effectively carried out during the "first-stage aging at low temperature", and the "absorption of moisture" is effectively carried out during the "second-stage aging at room temperature", resulting in brown rice with a chewy texture.

[0039] Specifically, it is considered that the enzymes contained in koji act on the brown rice, softening the unique crackling texture of the brown rice and generating a chewy feeling. Furthermore, by aging and storing the brown rice at room temperature after cooking, the brown rice absorbs the moisture remaining in the pouch, softening the sticky texture of freshly cooked rice. As a result, it is considered that an appropriate texture that is not too soft and a chewy feeling can be obtained.

[0040] Hereinafter, the present invention will be described in detail based on examples. (Example) 45 g of washed brown rice, 4 g of adzuki beans, 8 g of black rice, 90 ml (approx. 90 g) of water, 3 g of salt koji, and air (the amount of air when the vacuum degree is 60%) were sealed in a retort container with a capacity of 200 ml and placed in a temperature environment of 4 degrees for 36 hours. Then, it was placed in a high-temperature and high-pressure cooker (Master Kiln (manufactured by Panasonic): FCS-KM77) at 121 degrees and 0.22 Mpa for 9 minutes to cook the brown rice. After the cooking was completed, by blowing air toward the surface of the retort container, the surface temperature of the sealed retort container was reduced to 20 degrees within 60 minutes after the cooking was completed. Then, the retort container containing the ingredients was placed in a temperature environment of 20 degrees for 24 hours to produce retort brown rice.

[0041] Regarding the retort brown rice produced in this way, a sensory evaluation was conducted by 5 panelists, and the evaluation was that "a strong chewy texture was felt".

[0042] Figures 2 - 7 show the results (average value of 5 persons) of sensory evaluations regarding the chewy texture, conducted on a five - point scale (5: very good, 4: good, 3: normal, 2: not very good, 1: not good), by varying the "aging time in the first stage", "aging time in the second stage", "aging temperature in the second stage", "surface temperature to be reduced by blowing after rice cooking is completed", "time until the surface temperature is reduced to 20 degrees by blowing after rice cooking is completed", "presence or absence of salt koji", and "amount of water". Note that, except for the items to be varied, the operations were carried out under the same conditions (temperature, time) as those in the above - mentioned examples, and the sensory evaluation was conducted without informing the panelists of the varied items. Also, regarding the "aging temperature in the first stage", as described above, since aging does not progress at 0 degrees or below and there is a concern that Escherichia coli may proliferate at 5 degrees or above, the temperature environment is set at 0 - 5 degrees and the conditions were not changed as it does not contribute to the chewy texture.

[0043] In the "sensory test conducted by varying the aging time in the first stage" shown in Figure 2, the panelists' impression was "I was concerned about the crackling feeling of brown rice in those with a short resting time." On the other hand, although a small number of panelists had the impression that "Brown rice left to rest for 60 hours was too soft and I could hardly feel the chewy texture.", it is presumed that when left to rest for more than 60 hours, the chewy texture becomes less perceivable.

[0044] From the results of this sensory test, it was found that the "aging time in the first stage" is preferably 12 - 60 hours.

[0045] In the "sensory test conducted by varying the aging time in the second stage" shown in Figure 3, the panelists' impression was "I was concerned about the moisture content of the freshly cooked brown rice."

[0046] From the results of this sensory test, it was found that the "aging time in the second stage" is preferably 12 hours or more. Although the optimal texture was obtained when left to rest for 24 hours, the change was at a level that was hardly noticeable when compared with the sample left to rest for 12 hours.

[0047] In the sensory test of "changing the temperature in the second-stage aging" shown in Figure 4, the panelists felt that "in the refrigerated environment (5 degrees), the rice felt slightly hard. It is thought that the starch contained in the rice changed to a dietary fiber called resistant starch when cooled. There was not much change felt after 10 degrees."

[0048] And from the results of this sensory test, it was found that the "temperature in the second-stage aging" is preferably 10 degrees or more.

[0049] In the sensory test of "changing the surface temperature reduced by blowing after cooking" shown in Figure 5, the panelists felt that "in the refrigerated environment (5 degrees), the rice felt slightly hard. In the case of too high temperature zones, there was also a lot of moisture remaining, and it was difficult to obtain a chewy texture."

[0050] And from the results of this sensory test, it was found that the "surface temperature reduced by blowing after cooking" is preferably 10 - 25 degrees, and particularly preferably 15 - 20 degrees.

[0051] In the sensory test of "changing the time until the surface temperature is reduced to 20 degrees by blowing after cooking" shown in Figure 6, the panelists felt that "in the case of 1 hour, the chewy texture was felt a little strongly."

[0052] And from the results of this sensory test, it was found that the "time until the surface temperature is reduced to 20 degrees by blowing after cooking" is preferably about 1 hour. However, since the difference in the sensory test due to the temperature reduction time was slight, it is considered that the temperature zone to be reduced is more important than the time for the temperature reduction. That is, it is considered important to "first reduce the surface temperature to 10 - 25 degrees (particularly 15 - 20 degrees) by blowing and then let it rest in a temperature environment of 10 degrees or more" in order to obtain a chewy texture.

[0053] In the sensory test with and without koji shown in Figure 7, many panelists commented that "the rice with koji had a better koji flavor and was tastier." However, some people commented that they "preferred the harder rice without koji."

[0054] The results of this sensory test showed that, although it depends on personal preference, the use of shio koji was generally preferred.

[0055] In the "sensory test with varying amounts of water" shown in Figure 8, many panelists commented that "when the amount of water was low, the hardness of the rice and the gritty texture of the beans bothered me. Conversely, when the amount of water was high, the texture became more like porridge, with no sense of chewiness at all, and the flavor was bad and it did not taste salty." In Figure 8, ratio 1 indicates the ratio of the weight of water to the total weight, and ratio 2 indicates the ratio of the weight of water to the weight of brown rice.

[0056] The results of this sensory test showed that the "amount of water" should preferably be 133.3-222.2% of the weight of the brown rice, and more preferably 155.6-200.0%.

[0057] Also, although not shown in the figure, with regard to flavor, brown rice produced within the above preferred range was rated as "no problem at all."

[0058] In addition, although not shown in the figures, even when the amounts of ingredients were changed within the ranges described in the embodiments of the present invention, there was no significant change in the evaluations in Figures 2 to 8.

[0059] From the above results, it can be seen that the retorted brown rice obtained according to the present invention has a chewy texture.

Claims

1. At least a step of manufacturing a retort container containing ingredients by sealing brown rice, water, koji, and air in a retort container; A step of performing the first-stage aging of the brown rice by placing the retort container containing the ingredients in a temperature environment of 0 - 5 degrees for 12 - 60 hours; After the completion of the first-stage aging, a step of cooking the brown rice by placing the retort container containing the ingredients in a high-temperature and high-pressure cooker; After the completion of the rice cooking, a step of performing the second-stage aging of the brown rice by placing the retort container containing the ingredients in a temperature environment of 10 degrees or higher for 12 hours or more; A koji two-stage aging preparation method characterized by comprising the above.

2. In the step of performing the second-stage aging, after reducing the surface temperature of the retort container containing the ingredients to the range of 10 - 25 degrees by blowing air toward the surface of the retort container containing the ingredients, the retort container containing the ingredients is placed in a temperature environment of 10 degrees or higher for 12 hours or more. The koji two-stage aging preparation method according to Claim 1, characterized in that.

3. In the step of performing the second-stage aging, after reducing the surface temperature of the retort container containing the ingredients to the range of 15 - 20 degrees by blowing air toward the surface of the retort container containing the ingredients, the retort container containing the ingredients is placed in a temperature environment of 10 degrees or higher for 12 hours or more. The koji two-stage aging preparation method according to Claim 2, characterized in that.

4. The weight of the water sealed in the retort container is 133.3 - 222.2% of the weight of the brown rice. The koji two-stage aging preparation method according to Claim 1, characterized in that.

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