JP2020130051A - α-CONVERTED DRY BROWN RICE AND METHOD FOR PRODUCING THE SAME - Google Patents

Abstract

To provide a single-grained α-converted dry brown rice that has good restoration and nutrient absorption and that has, when restored, the original eat-texture of cooked rice, and to provide an efficient method for producing the same.SOLUTION: The α-converted dry brown rice is produced by a method including: a swelling step in which brown rice is foamed in a condition of 150 to 280°C for 30 to 200 seconds to yield swollen brown rice; a α-conversion step in which the swollen brown rice is subjected to α-conversion assuming the before-heating immersion treatment less than 2 hours; an immersion step in which the α-converted rice by the α-conversion step is subjected to immersion treatment by an enzyme liquid that contains α-amylase and is adjusted to an optimal temperature for α-amylase; and a drying step in which the immersion treated rice by the immersion step is dried.SELECTED DRAWING: Figure 1

Description

The present invention relates to pregelatinized dried brown rice and a method for producing the same. More specifically, the present invention relates to single-grained pregelatinized dried brown rice having a favorable texture when restored, and a method for producing the same.

Consumers' health consciousness toward food is increasing year by year, and cooked rice is no exception. Among cooked rice, brown rice, which is richer in vitamins, minerals, dietary fiber, etc. than polished rice, is attracting attention as one of the healthy foods.

However, since the outside of brown rice is covered with pericarp and seed coat, it takes time to absorb water and gelatinize, and it is more difficult to cook rice than polished rice. Therefore, instant brown rice (pregelatinized dried brown rice) obtained by drying pregelatinized brown rice, which can be quickly restored by simply immersing it in hot water or water, has been developed.

As such instant brown rice, for example, Patent Document 1 discloses instant brown rice obtained by cooling pregelatinized brown rice to a freezing temperature or lower, freezing it, thawing it, and then drying it.

JP-A-2009-39029

However, although such instant brown rice has good resilience in a short time, the texture after restoration does not become the original texture of cooked rice and is not satisfactory. If the original texture of cooked rice after this restoration is pursued and the pregelatinized state of brown rice is adjusted, the rice grains are likely to bind to each other due to the stickiness of the surface, and it becomes difficult to make single grains. In addition, this may make it impossible to achieve restoration in a short time. Further, due to the presence of the pericarp and seed coat described above, there is a problem that even in the production stage of instant brown rice, it takes time for the brown rice to be hard to absorb water and to be gelatinized as in the case of cooking rice.

Therefore, an object of the present invention is to provide a single-grained pregelatinized dried brown rice having good resilience and nutrient absorption and having the original texture of cooked rice when restored, and an efficient production method thereof. And.

In order to solve the above problems, the present inventor diligently studied and performed a swelling step in which brown rice was foamed under the conditions of 150 to 280 ° C. and 30 to 180 seconds to obtain swelled brown rice, and the swelled brown rice was dipped before heating. The pregelatinization step of pregelatinization in less than 2 hours, and the dipping step of dipping the rice pregelatinized by the pregelatinization step with an enzyme solution containing α-amylase and adjusted to the optimum temperature of α-amylase. By a manufacturing method including a drying step of drying the rice soaked by the dipping step, the rice is made into single grains having good restoration property and high nutrient absorption, and further having the original texture of cooked rice when restored. We have found that pregelatinized and dried brown rice can be efficiently produced, and completed the present invention.

That is, the present invention is the following (1) to (7).
(1) A swelling step in which brown rice is foamed at 150 to 280 ° C. for 30 to 180 seconds to obtain swelled brown rice, and an pregelatinization step in which the swelled brown rice is pregelatinized in less than 2 hours. A dipping step of dipping the rice pregelatinized by this pregelatinization step with an enzyme solution containing α-amylase and adjusted to the optimum temperature of the α-amylase, and a dipping step of dipping the rice soaked by this dipping step. A method for producing pregelatinized dried brown rice, which comprises a drying step of drying.
(2) The method for producing pregelatinized dried brown rice according to (1), wherein the swelling step is a step of foaming brown rice with hot air and / or microwaves.
(3) The method for producing pregelatinized dried brown rice according to (1) or (2), wherein the swollen brown rice having a bulk specific gravity of 0.53 to 0.89 g / ml is obtained by the swelling step.
(4) The pregelatinized dry brown rice according to any one of (1) to (3), wherein the pregelatinization step is a step of adding water to the swollen brown rice and then pregelatinizing the brown rice without pre-heating soaking treatment. Manufacturing method.
(5) The method for producing pregelatinized dried brown rice according to any one of (1) to (4), wherein the immersion treatment time in the immersion step is 2 seconds to 3 minutes.
(6) The method for producing pregelatinized dried brown rice according to any one of (1) to (5), wherein the optimum temperature of the α-amylase is 35 to 80 ° C.
(7) Single-grained pregelatinization having a bulk specific gravity of 0.30 to 0.45 g / ml and a water absorption rate of 240 to 300% by mass 5 minutes after being immersed in boiling water at 98 ° C. Dried brown rice.

According to the present invention, it is possible to provide single-grained pregelatinized dried brown rice that has good resilience, high nutrient absorption, and has the original texture of cooked rice when restored. It is also possible to provide an efficient method for producing the pregelatinized dried brown rice, which has improved water absorption of brown rice and is easy to cook and steam.

An example of the method for producing pregelatinized dried brown rice according to the present invention is shown as a process diagram. It is a micrograph which observed the side surface and the cross section of the swollen brown rice grain after the swelling step in the production of pregelatinized dry brown rice of Examples 3, 4 and 6 (drawing substitute photograph). The upper row is a cross section of brown rice grains, and the lower row is a photograph of the surface of brown rice grains. From left to right, untreated raw brown rice, which is a control product, expanded brown rice in the production of Example 3, and expanded brown rice in the production of Example 4. It is the swollen brown rice in the production of Example 6.

The present invention will be described.
The present invention comprises a swelling step in which brown rice is foamed at 150 to 280 ° C. for 30 to 180 seconds to obtain swelled brown rice, and an pre-heating immersion treatment of less than 2 hours to pregelatinize the swelled brown rice. , The rice that has been pregelatinized by the pregelatinization step is dipped with an enzyme solution containing α-amylase and adjusted to the optimum temperature of α-amylase, and the rice that has been dipped by the dipping step is dried. A method for producing pregelatinized dried brown rice including a drying step, and a water absorption rate of 240 to 300 5 minutes after being immersed in boiling water at 98 ° C. and having a bulk specific gravity of 0.30 to 0.45 g / ml. It is a mass% single grained pregelatinized dried brown rice.

First, a method for producing pregelatinized dried brown rice according to the present invention will be described in detail.
In the method for producing pregelatinized dried brown rice according to the present invention, brown rice is used as the raw material rice. The term "brown rice" means rice in which rice husks have been removed from the paddy and has not been milled (the peel, seed coat and paste layer (so-called rice bran) have not been removed). In the present invention, only brown rice is used. Rice bran rice, which contains about 70% of starch and is almost amylopectin (more sticky when gelatinized), can also be used. Further, the variety of rice is not particularly limited, but it is more preferable to use brown rice or brown rice having an amylose content of 15% by mass or more in the starch, which is more suitable for the texture when restored. It is preferable in terms of obtaining pregelatinized dried brown rice. The brown rice used in the present invention may be subjected to a rice washing step for removing stains on the surface, if necessary. It should be noted that this rice washing step is different from the step for washing away the skin bran on the surface of the polished rice, which is performed before the pregelatinization of the polished rice.

Then, such brown rice is first foamed in the swelling step to obtain swelled brown rice. In this swelling step, brown rice is foamed under the conditions of a treatment temperature of 150 to 280 ° C., preferably 170 to 250 ° C., more preferably 175 to 225 ° C., and a treatment time of 30 to 180 seconds, preferably 35 to 100 seconds. , Swelled brown rice. At this time, it is preferable to adjust the state of brown rice, heat source, etc. in the apparatus so that the heating is as uniform as possible. Further, the humidity inside the device may be adjusted. By using such swelled brown rice, it is possible to improve the water absorption, rice-cooking property and steamability in the subsequent pregelatinization step, and the pregelatinization of brown rice can be easily performed. In this swelling step, foaming with hot air and / or microwave is more preferable in terms of efficiently obtaining suitable swelled brown rice. Further, in this expansion step, two-step heating and pressurization are not essential. If the treatment temperature in this swelling step is lower than 150 ° C. or the treatment time is shorter than 30 seconds, the swelling of brown rice is likely to be insufficient, which is not preferable. Furthermore, if the treatment temperature is higher than 280 ° C. or the treatment time is longer than 180 seconds, the texture when the pregelatinized dried brown rice is restored may be adversely affected, and the brown rice may be easily burnt. It is not preferable because it is expensive.

Here, it is more preferable that the brown rice is swelled brown rice having a bulk specific gravity of 0.53 to 0.89 g / ml, preferably 0.55 to 0.87 g / ml by the swelling step. This is because the water absorption, rice cooking property, and steaming property in the subsequent pregelatinization step are further improved, and the restorability and texture of the final product, pregelatinized dried brown rice, are further improved. If the bulk specific density of this swollen brown rice is more than 0.89 g / ml, the subsequent pregelatinization step may be difficult, and the swelling progresses further, and the bulk specific gravity of the swollen brown rice is less than 0.53 g / ml. Then, the texture of the obtained pregelatinized dried brown rice may not be suitable. In the present invention, the bulk specific gravity can be measured by a method of measuring a sample in a measuring cylinder having a predetermined volume (for example, 100 mL) and measuring the mass to obtain a value of g / ml.

Next, the obtained swollen brown rice is pregelatinized in the pre-heating step soaking for less than 2 hours. In this pregelatinization step, water is added to the swollen brown rice, preferably 1 to 2.5 times, more preferably 1.5 to 2.0 times the mass of the brown rice used as the raw material, and then if necessary. After performing pre-immersion treatment at room temperature (5 to 35 ° C) for less than 2 hours, heat to a temperature exceeding room temperature, preferably 70 ° C or higher, and more preferably hold at a temperature of around 100 ° C for 20 to 30 minutes. This is a process in which water enters the rice starch and swells due to water absorption during heating. Here, this pregelatinization step can be performed in a batch system or a continuous system by a known method such as cooking rice or steaming, and may be pressurized and heated, and is not particularly limited. Then, it is preferable to carry out the pregelatinization so that the mass of the pregelatinized rice is 200 to 300% by mass, more preferably 200 to 250% by mass, based on the mass of the brown rice used as the raw material. In the present invention, at least a part of the pericarp and the seed coat is torn by the swelling step, and the swelled brown rice having increased water absorption is pregelatinized. Therefore, in the pregelatinization of brown rice, water is usually permeated into the inside of the rice. It is also characterized by not requiring a long-time pre-heating dipping treatment at room temperature, which is necessary. In the present invention, the pre-heating dipping treatment time is preferably less than 2 hours, preferably within 1.5 hours, more preferably within 1 hour, and most preferably without pre-heating dipping treatment. .. When the pre-heating soaking treatment is performed for 2 hours or more, the rice grains are fragile in the drying treatment, and the single-grained pregelatinized brown rice cannot be obtained. In particular, when the swelling temperature is set high in the swelling step, it is preferable that this preheating dipping treatment is as short as possible.

Further, the rice gelatinized by the pregelatinization step is immersed in an enzyme solution containing α-amylase and adjusted to the optimum temperature of α-amylase (immersion treatment after heating) in the dipping step. The immersion treatment time is preferably 2 seconds to 3 minutes, and more preferably 5 seconds to 1 minute. The "immersion treatment" in this dipping step includes not only the treatment of immersing the pregelatinized rice in a sufficient amount of enzyme solution for the rice (immersion in a narrow sense), but also the pregelatinized rice. It also includes a treatment of spraying the enzyme solution (leaving after spraying if necessary) and a treatment of dropping the enzyme solution on pregelatinized rice (leaving after dropping if necessary). Then, the liquid is drained after this immersion treatment. By this dipping treatment and draining, the sticky component on the surface of the pregelatinized rice grains can be washed away, and the rice grains are less likely to bind to each other in the subsequent drying process. It will be easier to obtain.

If the immersion treatment time is less than 2 seconds, the effect of the immersion treatment after heating may not be sufficiently obtained. Further, when the immersion treatment time exceeds 3 minutes, α-amylase acts not only on the surface of the rice grains but also on the inside of the rice grains, so that the texture of the obtained pregelatinized dried brown rice after restoration tends to deteriorate. Further, it is necessary to use α-amylase in the post-heating dipping treatment of the present invention, and even if other types of amylase such as β-amylase are used, the desired effect cannot be obtained.

The amount of α-amylase used in the enzyme solution is preferably a solution in which α-amylase is 0.0001 to 0.002% by mass. The optimum temperature of the α-amylase used is preferably 35 to 80 ° C, more preferably 50 to 70 ° C. That is, it is preferable to use an enzyme solution adjusted to 35 to 80 ° C., more preferably 50 to 70 ° C. The enzyme solution is preferably kept in this temperature range during the post-heating and immersion treatment. This is because the action of α-amylase can be fully exerted in a short time by using an enzyme solution adjusted to the optimum temperature of α-amylase to be used.

In the present invention, the treatment with the enzyme solution containing α-amylase is characterized in that it is performed on the pregelatinized brown rice that has been pregelatinized by the pregelatinization step and has not been pregelatinized. However, even if the treatment with an enzyme solution containing this α-amylase is performed, the desired effect cannot be obtained.

Then, the rice soaked in the dipping step is dried in the drying step. The drying in this drying step can be performed by a method such as hot air drying, freeze drying (FD) drying, and microwave drying. At this time, it is preferable to adjust the state of rice, heat source, etc. in the apparatus so that the drying is as uniform as possible. It is more preferable to perform drying by hot air drying (for example, hot air drying conditions at 90 to 100 ° C. for 50 to 100 minutes) from the viewpoint of preventing excessive swelling of the obtained pregelatinized dried brown rice. Further, in this hot air drying, the humidity condition may be adjusted. Further, it is preferable to dry the obtained pregelatinized dried brown rice so that the water content is 15% by mass or less from the viewpoint of long-term storage.
Here, in order to pre-dry the surface of the rice grains before drying and inactivate the α-amylase adhering to the surface of the rice grains, a steaming step of steaming the soaked rice in the dipping step may be performed before the drying step. good. As a result, the binding of rice grains in the drying step can be further suppressed, and the excessive action of α-amylase can be further suppressed.

Then, the obtained pregelatinized dried brown rice may be cooled to about room temperature by allowing it to cool, and then filled in a packaging container by a packaging / filling step. This packaging container is not particularly limited, and examples thereof include a packaging container having a shape such as a bag shape, a cup shape, and a tray shape, and which can be sealed after filling the contents.

Further, the method for producing pregelatinized dried brown rice according to the present invention may include any steps other than the above as long as the effects of the present invention are not significantly affected. An example of a method for producing pregelatinized dried brown rice according to the present invention is shown in FIG.

Next, the pregelatinized dried brown rice of the present invention will be described in detail.
In the pregelatinized dried brown rice of the present invention obtained by the above-mentioned production method or the like, the pericarp and seed coat on the surface layer are torn to expose at least a part of the paste powder layer. This makes it possible to restore in a short time (for example, within 5 minutes after soaking in boiling water at 90 to 100 ° C.), improving its digestibility, and brown rice has vitamins, minerals, and food as compared with polished rice. It is rich in fiber and the like, and the absorbability (nutrition absorbability) of nutrient components represented by these is also enhanced. In addition, since it is made into a single grain and can be quickly restored by simply immersing it in boiling water or water, it can be restored in the required amount and eaten, and can be suitably used for outdoor use or emergency use.

As described above, the pregelatinized dried brown rice of the present invention is singularized in a dry state and can be uniformly restored, so that the texture after restoration can be clearly felt as rice grains. .. Here, in the present invention, "single grain" means a state in which 70% or more, preferably 80% or more of the rice is a single grain (excluding broken rice that does not maintain the shape of the rice grain). To do. This can be calculated from the mass ratio of a single grain of pregelatinized dried brown rice.

The pregelatinized dried brown rice of the present invention has a bulk specific gravity of 0.30 to 0.45 g / ml, preferably 0.32 to 0.43 g / ml, and is hot water at 98 ° C. (the temperature at the start of immersion is high). The water absorption rate 5 minutes after being immersed in hot water at 98 ° C. is 240 to 300% by mass, preferably 250 to 280% by mass. The pregelatinized dried brown rice of the present invention having such a bulk specific density and a water absorption rate can be restored in a short time with boiling water or the like, and when restored, it has the original texture of cooked rice. Here, the bulk specific gravity means a value measured by the same method as described above, and the water absorption rate is 5 after immersing the pregelatinized dried brown rice in boiling water at 98 ° C. with respect to the mass of the pregelatinized dried brown rice. It means a value expressed by a percentage of the mass ratio after minutes.
Further, the pregelatinized dried brown rice of the present invention is a porridge brown rice having an amylose content of 15% by mass or more in starch and / or a pregelatinized dried brown rice using sardine brown rice, which gives a better texture when restored. It is preferable because it is suitable.

The pregelatinized dried brown rice of the present invention may contain any additive component as long as it satisfies the above constitution and does not significantly affect the effect of the present invention, but may not contain the additive component.

Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples, and various modifications can be made within the technical idea of the present invention.

(Preparation of pregelatinized dried brown rice 1)
First, the following test was carried out in order to confirm the influence of the presence or absence of the swelling step (swelling treatment) in the production of pregelatinized dried brown rice.
100 g of brown rice (Haenuki 50%, Tsuyahime 50%, both produced in Yamagata Prefecture) as a raw material was swelled with hot air at 200 ° C for 39 seconds, and the obtained swelled brown rice (bulk specific gravity 0.65 g / ml) was obtained. ) Was hydrated 1.8 times as much as the raw material brown rice and immersed at room temperature for 24 hours. This is cooked with a rice cooker (microcomputer rice cooker JBG-B100, manufactured by Tiger Corporation), and the obtained rice cooked rice is adjusted to about 60 ° C. 0.05% neospidase (formulation containing 1% α-amylase, optimal). The temperature was 60 to 70 ° C., and the mixture was transferred to an enzyme solution containing Nagase ChemteX Corporation) and immersed for 45 seconds with stirring. After soaking in this enzyme solution, the liquid was drained, and the rice after the liquid drain was placed in a drying tray in a flatly stretched state, and hot air dried under the conditions of 95 ° C. for 75 minutes (Comparative Example A).

On the other hand, as Comparative Example B, after adding 1.8 times the amount of water to 100 g of the same raw material brown rice and immersing it at room temperature for 24 hours, pregelatinized dried brown rice was prepared by the same method as in Comparative Example A after cooking rice. The weight, bulk specific density and state of brown rice in each of these steps are summarized in Table 1 below. In the table, "separation from the kettle" means the state when the cooked rice is separated from the kettle of the rice cooker, and "flattened state in the drying tray" means the rice that has been drained after being immersed in the enzyme solution. The "unraveled state after drying" represents the state when the dried brown rice on the drying tray is unraveled after being dried with hot air (the same applies to Tables 2 and 4 described later). ).

As a result, since the brown rice of Comparative Example A, which was swelled before cooking rice, had extremely high water absorption, all the water was absorbed by the 24-hour immersion treatment at room temperature before cooking rice. When this brown rice was cooked and then dried, the rice grains collapsed and pregelatinized dried brown rice could not be obtained. Therefore, the weight after drying and the loosened state after drying could not be confirmed (ND). In Comparative Example B in which the swelling treatment before cooking the rice was not performed, the resilience and the texture after the restoration of the obtained pregelatinized dried brown rice were not preferable.

(Preparation of pregelatinized dried brown rice 2)
Next, the following test was carried out to confirm the effect of the pre-heating immersion time on the production of pre-heated dried brown rice.
100 g of brown rice (Haenuki 50%, Tsuyahime 50%, both produced in Yamagata Prefecture) as a raw material was swelled with hot air at 200 ° C for 39 seconds, and the obtained swelled brown rice (bulk specific density 0.65 g / ml) 1.8 times the amount of raw brown rice was added to the water. Then, the pre-heating immersion time 0 hours (no immersion, Example 1), the pre-heating immersion time 0.5 hours (immersion 0.5h, Example 2), and the pre-heating immersion time 2 hours (immersion 2h, Comparative Example 1). ), All of which were cooked with a rice cooker (microcomputer rice cooker JBG-B100, manufactured by Tiger Magic Bottle Co., Ltd.), and each of the obtained rice cooked rice was adjusted to about 60 ° C. The mixture was transferred to an enzyme solution containing 0.05% neospidase (preparation containing 1% α-amylase, optimum temperature 60 to 70 ° C., manufactured by Nagase ChemteX Corporation) and immersed with stirring for 45 seconds. After immersion in this enzyme solution, the liquid was drained, and the rice after the liquid drain was placed in a drying tray in a flatly stretched state, and hot air dried under the conditions of 95 ° C. for 75 minutes. The weight, bulk specific density and state of brown rice in each of these steps are summarized in Table 2 below. In each case, it was possible to obtain single-grained pregelatinized dried brown rice.

Then, each of the pregelatinized dried brown rice of Examples 1 and 2 and Comparative Example 1 thus obtained was subjected to a sensory evaluation. Specifically, 30 g of these pregelatinized dried brown rice was placed in a cup-shaped container together with the soup, and hot water at 98 ° C. was poured into the container, and after 5 minutes, the brown rice was reconstituted in hot water for sensory evaluation.
The sensory evaluation is based on the following evaluation criteria for the three items of resilience of pregelatinized dried brown rice (good return without a core in the center), texture (elasticity and stickiness), and rice grain texture (appearance grain texture). Was unified so that it would be a common evaluation standard among panelists. Specifically, using Example 1 as a reference sample (evaluation is 4.0 for all items), 10 panelists comparatively sensory-evaluate each sample by relative evaluation based on the following evaluation criteria, and this average value. Was calculated. The results are shown in Table 3 below.

<Evaluation criteria for stability, texture and rice grain>
5: Very good (better than Example 1)
4: Somewhat good (equivalent to Example 1)
3: Good (slightly inferior to Example 1 but good)
2: Slightly bad (inferior to Example 1)
1: Bad (much inferior to Example 1)

As a result, the pregelatinized dried brown rice of Examples 1 and 2 had good resilience, and also had a good texture and texture of rice grains. On the other hand, the pregelatinized dried brown rice of Comparative Example 1 had good resilience, but the rice grains collapsed, and the feeling of rice grains was not particularly preferable.

(Preparation of pregelatinized dried brown rice 3)
Next, the following test was carried out to confirm the influence of the swelling treatment conditions on the production of pregelatinized dried brown rice.
After washing 100 g of brown rice (50% Haenuki, 50% Tsuyahime, all produced in Yamagata Prefecture) as a raw material to remove stains on the surface, 150 ° C for 156 seconds, 175 ° C for 83 seconds, 200 ° C for 70 seconds, and 225 ° C. Each of the swelled brown rice obtained by swelling with hot air under four conditions of 52 seconds (bulk specific gravity is 0.86 g / ml, 0.74 g / ml, 0.63 g / ml, 0.59 g / ml, respectively). 1.8 times the amount of raw brown rice was added to the water. Then, in each case, rice was cooked with a rice cooker (microcomputer rice cooker JBG-B100, manufactured by Tiger Corporation) without taking a pre-heating immersion time, and each of the obtained rice cooked rice was adjusted to about 60 ° C. at 0.05%. The mixture was transferred to an enzyme solution containing neospitase (preparation containing 1% α-amylase, optimum temperature 60 to 70 ° C., manufactured by Nagase ChemteX Corporation) and immersed with stirring for 45 seconds. After soaking in this enzyme solution, the liquid was drained, and the rice after the liquid drain was placed in a drying tray in a flatly stretched state, and hot air dried under the conditions of 95 ° C. for 75 minutes (Examples 3 to 6).

On the other hand, as Comparative Example 2, 100 g of the same raw material brown rice was washed, 1.8 times more water was added, and the rice was soaked at room temperature for 24 hours. After cooking the rice, it was gelatinized and dried by the same method as in Examples 3 to 6. Brown rice was prepared. The weight, bulk specific density and state of brown rice in each of these steps are summarized in Table 4 below. In each case, it was possible to obtain single-grained pregelatinized dried brown rice.

For each of the puffed brown rice after the puffing step during these manufacturing steps, the side surface and the cross section (cross section of the puffed brown rice grains cut in the lateral direction) were observed. Table 5 shows the observation findings and the bulk specific density of each swollen brown rice.
For each swelled brown rice after the swelling step during the manufacturing process of Examples 3, 4 and 6, the side surface and the cross section of the grain were further observed under a microscope under the following conditions, and the side surface and the cross section of the untreated brown rice grain were further observed. Compared. This micrograph is shown in FIG.
Equipment used: Digital Microscope VHX-1000 (manufactured by KEYENCE)
Magnification: 50 times

Further, each of the obtained pregelatinized dried brown rice of Examples 3 to 6 and Comparative Example 2 was subjected to sensory evaluation using Example 1 as a reference sample by the same method as described above. The results are shown in Table 6 below.

As a result, the pregelatinized dried brown rice of Examples 3 to 6 had better resilience and a better texture than the pregelatinized dried brown rice of Comparative Example 2. Further, when the swelling treatment temperature was raised, the bulk specific gravity of the obtained swelled brown rice became smaller, and the recoverability of the obtained pregelatinized dried brown rice tended to be improved. When the swelling treatment temperature was higher than 200 ° C., the rice grain feeling of the obtained pregelatinized dried brown rice tended to be slightly lowered. Furthermore, from the appearance evaluation of the swollen brown rice after the swelling step, it was clarified that at least a part of the epidermis (pericarp and seed coat) of the brown rice was torn after the swelling step in all of Examples 3, 4 and 6. (Fig. 2).

In addition, the pregelatinized dried brown rice of Examples 3, 6 and Comparative Example 2 was measured for its bulk specific density and water absorption 5 minutes after being immersed in boiling water at 98 ° C. As a result, the bulk specific gravity of the pregelatinized dried brown rice of Example 3 was 0.40 g / ml and the water absorption rate was 255% by mass, and the bulk specific gravity of the pregelatinized dried brown rice of Example 6 was 0.34 g / ml and the water absorption rate. Was 276% by mass. On the other hand, the bulk specific gravity of the pregelatinized dried brown rice of Comparative Example 2 was 0.45 g / ml, but the water absorption rate was 201% by mass.

(Preparation of pregelatinized dried brown rice 4)
The following tests were carried out to further confirm the effect of swelling treatment conditions on the production of pregelatinized dried brown rice.
After washing 100 g of brown rice (100% Haenuki, produced in Yamagata Prefecture) as a raw material to remove stains on the surface, it is swelled with hot air under three conditions of 240 ° C for 42 seconds, 260 ° C for 35 seconds, and 280 ° C for 32 seconds. To each of the obtained swollen brown rice (bulk specific gravity is 0.58 g / ml, 0.56 g / ml, 0.55 g / ml, respectively), 1.8 times the amount of the raw brown rice was added. Then, in each case, rice was cooked with a rice cooker (microcomputer rice cooker JBG-B100, manufactured by Tiger Corporation) without taking a pre-heating immersion time, and each of the obtained rice cooked rice was adjusted to about 60 ° C. at 0.05%. The mixture was transferred to an enzyme solution containing neospitase (preparation containing 1% α-amylase, optimum temperature 60 to 70 ° C., manufactured by Nagase ChemteX Corporation) and immersed with stirring for 45 seconds. After soaking in this enzyme solution, the liquid was drained, and the rice after the liquid drain was placed in a drying tray in a flatly stretched state, and hot air dried under the conditions of 95 ° C. for 75 minutes (Examples 7 to 9).

Then, each of the pregelatinized dried brown rice of Examples 7 to 9 thus obtained was subjected to sensory evaluation by the same method as described above, using Example 1 as a reference sample. The results are shown in Table 7 below.

As a result, even if the swelling treatment temperature is set to 240 ° C., 260 ° C. or 280 ° C., the rice grain feeling of the pregelatinized dried brown rice obtained as the swelling treatment temperature increases tends to decrease slightly, but the sensory evaluation is generally good as a whole. there were. However, in the swelling treatment at 260 ° C. and 280 ° C., the brown rice tended to be slightly burnt in the swelling treatment, and the swelling treatment time was short, so that the treatment tended to vary slightly.

Further, the pregelatinized dried brown rice of Example 9 was measured for its bulk specific density and water absorption 5 minutes after being immersed in boiling water at 98 ° C. The measurement results for each lot produced twice by the same method were a bulk specific density of 0.38 g / ml and a water absorption rate of 259 mass%, and a bulk specific density of 0.35 g / ml and a water absorption rate of 282 mass%, respectively.

(Preparation of pregelatinized dried brown rice 5)
The following test was carried out to confirm the effect of the enzyme solution immersion time on the production of pregelatinized dried brown rice.
After washing 100 g of brown rice (100% Haenuki, produced in Yamagata Prefecture) as a raw material to remove stains on the surface, swelling treatment was performed with hot air at 225 ° C for 52 seconds, and the obtained swelled brown rice (bulk specific gravity is 0). .59 g / ml) was hydrated 2.0 times as much as the raw material brown rice. Then, the rice was cooked with a rice cooker (microcomputer rice cooker JBG-B100, manufactured by Tiger Corporation) without taking the immersion time before heating, and the obtained rice cooked rice was divided into three and adjusted to about 60 ° C. 0.05. It was transferred to an enzyme solution containing% neospitase (preparation containing 1% α-amylase, optimum temperature 60 to 70 ° C., manufactured by Nagase ChemteX Corporation) and immersed with stirring for 2 seconds, 45 seconds and 3 minutes, respectively. After immersion in this enzyme solution, the liquid was drained, and the rice after the liquid drain was placed in a drying tray in a flatly stretched state, and hot air dried under the conditions of 95 ° C. for 75 minutes (Examples 10 to 12).

Then, each of the pregelatinized dried brown rice of Examples 10 to 12 thus obtained was subjected to sensory evaluation by the same method as described above, using Example 1 as a reference sample. The results are shown in Table 8 below.

As a result, the pregelatinized dried brown rice of Examples 10 and 11 had good evaluations in all items, but the pregelatinized dried brown rice of Example 12 having an enzyme immersion treatment time of 3 minutes was compared as a whole. Although the evaluation was good, the texture of rice tended to be slightly reduced and the texture tended to be soft.

Based on the above, the method for producing pregelatinized dried brown rice according to the present invention remarkably improves the water absorption and cookability of brown rice, and further, the restored and restored texture are preferable, and the single-grained pregelatinized dried brown rice is produced. It was shown to be obtained efficiently.

In addition, the present invention can also be produced in the same manner as in this example except that 100% Koshihikari (produced in Yamagata Prefecture) is used as the raw material brown rice instead of the raw material brown rice (Haenuki, Tsuyahime) used in this example. You can get pregelatinized dried brown rice.

Claims (7)

A swelling step of foaming brown rice at 150 to 280 ° C. for 30 to 180 seconds to obtain swelled brown rice, an pre-heating immersion treatment of less than 2 hours to pregelatinize the swelled brown rice, and the pregelatinization step. A dipping step of dipping the rice pregelatinized by the step with an enzyme solution containing α-amylase and adjusted to the optimum temperature of the α-amylase, and a drying process of drying the rice soaked by the dipping step. A method for producing pregelatinized dried brown rice, which includes a step. The method for producing pregelatinized dried brown rice according to claim 1, wherein the swelling step is a step of foaming brown rice with hot air and / or microwaves. The method for producing pregelatinized dried brown rice according to claim 1 or 2, wherein the swollen brown rice having a bulk specific gravity of 0.53 to 0.89 g / ml is obtained by the swelling step. The method for producing pregelatinized brown rice according to any one of claims 1 to 3, wherein the pregelatinization step is a step of adding water to the swollen brown rice and then pregelatinizing it without performing a pre-heating dipping treatment. The method for producing pregelatinized dried brown rice according to any one of claims 1 to 4, wherein the immersion treatment time in the immersion step is 2 seconds to 3 minutes. The method for producing pregelatinized dried brown rice according to any one of claims 1 to 5, wherein the optimum temperature of the α-amylase is 35 to 80 ° C. Single-grained pregelatinized dried brown rice having a bulk specific gravity of 0.30 to 0.45 g / ml and a water absorption rate of 240 to 300% by mass 5 minutes after being immersed in boiling water at 98 ° C.