JP7283917B2 - Pregelatinized dried brown rice and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to pregelatinized dried brown rice and a method for producing the same. More specifically, it relates to a single-grain pregelatinized dry brown rice that has a favorable texture when reconstituted, and a method for producing the same.

Consumers are becoming more and more health-conscious about food year by year, and rice is no exception. Among cooked rice, brown rice, which contains more vitamins, minerals, dietary fiber, etc. than polished rice, is attracting attention as one of health foods.

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

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

Japanese Patent Application Laid-Open No. 2009-39029

However, although such instant brown rice has good reconstitution property in a short time, the texture after reconstitution does not have the original texture of boiled rice and is not satisfactory. When the gelatinized state of the brown rice is adjusted in pursuit of the original texture of the cooked rice after restoration, the rice grains tend to stick together due to the stickiness of the surface, making it difficult to form single grains. Moreover, it may not be possible to achieve restoration in a short period of time. Furthermore, due to the presence of the above-mentioned pericarp and seed coat, there is a problem that brown rice does not easily absorb water and it takes a long time to gelatinize it, as in the case of cooking rice, even in the production stage of instant brown rice.

Accordingly, an object of the present invention is to provide a single granulated pregelatinized dried brown rice that has good reconstitution and nutrient absorption and has the original texture of cooked rice when reconstituted, and an efficient method for producing the same. and

In order to solve the above-mentioned problems, the present inventors have made intensive studies, and performed a puffing step to make puffed brown rice by foaming brown rice under conditions of 150 to 280 ° C. for 30 to 180 seconds, and a pre-heating soaking treatment of this puffed brown rice. a step of gelatinizing rice for less than 2 hours; a soaking step of soaking the rice that has been gelatinized by the step in an enzyme solution containing α-amylase and adjusted to an optimum temperature for α-amylase; By the manufacturing method including a drying step of drying the rice that has been soaked in the soaking step, the single grains have good resilience and high nutrient absorption, and have the original texture of cooked rice when rehydrated. The inventors have found that pregelatinized dry brown rice can be efficiently produced, and completed the present invention.

That is, the present invention is the following (1) to (7).
(1) A puffing step in which brown rice is foamed under conditions of 150 to 280° C. for 30 to 180 seconds to obtain puffed brown rice; a soaking step of immersing the rice that has been alpha-ized by this step in an enzyme solution containing α-amylase and adjusted to the optimum temperature for this α-amylase; and a drying step of drying.
(2) The method for producing pregelatinized dry brown rice according to (1), wherein the swelling step is a step of foaming the brown rice with hot air and/or microwaves.
(3) The method for producing pregelatinized dry brown rice according to (1) or (2), wherein the puffed brown rice having a bulk specific gravity of 0.53 to 0.89 g/ml is obtained by the puffing step.
(4) The pregelatinized dry brown rice according to any one of (1) to (3), wherein the pregelatinization step is a step of pregelatinizing the puffed brown rice after adding water to the puffed brown rice without subjecting it to soaking before heating. manufacturing method.
(5) The method for producing pregelatinized dried brown rice according to any one of (1) to (4), wherein the soaking treatment time in the soaking step is 2 seconds to 3 minutes.
(6) The method for producing pregelatinized dry brown rice according to any one of (1) to (5), wherein the α-amylase has an optimum temperature of 35 to 80°C.
(7) Single granulated gelatin 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 hot water at 98°C. dried brown rice.

According to the present invention, it is possible to provide single-grain pregelatinized dry brown rice that has good reconstitutability, high nutrient absorption, and has the original texture of cooked rice when reconstituted. In addition, it is possible to provide an efficient method for producing the above-mentioned pregelatinized dry brown rice, which improves the water absorbency of brown rice and facilitates rice cooking and steaming.

An example of the method for producing pregelatinized dried brown rice according to the present invention is shown as a process diagram. FIG. 10 is a microphotograph of side and cross sections of puffed brown rice grains after puffing step in production of pregelatinized dry brown rice of Examples 3, 4 and 6 (photographs substituting for drawings). FIG. The upper row is a cross section of the brown rice grain, and the lower row is a photograph of the surface of the brown rice grain. From the left, untreated raw brown rice as a control product, puffed brown rice in the production of Example 3, puffed brown rice in the production of Example 4, It is puffed brown rice in the production of Example 6.

The present invention will be described.
The present invention comprises a puffing step of foaming brown rice under conditions of 150 to 280° C. for 30 to 180 seconds to obtain puffed brown rice, and a pre-heating soaking treatment of the puffed brown rice for less than 2 hours to convert the puffed brown rice into gelatin. a soaking step of immersing the rice that has been gelatinized by the alpha-oxidizing step in an enzyme solution containing α-amylase and adjusted to the optimum temperature for α-amylase; and drying the rice that has been soaked by the soaking step. and a method for producing pregelatinized dried brown rice, which has a bulk specific gravity of 0.30 to 0.45 g/ml and a water absorption rate of 240 to 300 5 minutes after immersion in hot water at 98°C. % by mass of pregelatinized dry brown rice.

First, the 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 raw material rice. Brown rice means rice from which the husk has been removed and which has not been polished (pericarp, seed coat and aleurone layer (so-called rice bran) have not been removed). Instead, glutinous brown rice whose starch component is approximately 70% amylopectin (more sticky when pregelatinized) can also be used. The variety of rice is also not particularly limited, but it is preferable to use glutinous brown rice or glutinous brown rice having an amylose content in the starch of 15% by mass or more. It is preferable in terms of obtaining pregelatinized dry brown rice. In addition, the brown rice used in the present invention may be subjected to a rice-washing step to remove dirt on the surface, if necessary. This rice washing process is different from the process for washing off the bran on the surface of the polished rice, which is performed before the gelatinization of the polished rice.

Then, such brown rice is first foamed in the puffing step to obtain puffed brown rice. In this swelling step, brown rice is foamed under 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. , puffed brown rice. At this time, it is preferable to adjust the conditions of the brown rice and the heat source in the apparatus so that the heating is as uniform as possible. Also, the humidity in the apparatus may be adjusted. By using such puffed brown rice, it is possible to improve the water absorbency and rice-cooking/steaming properties in the subsequent gelatinization step, and the brown rice can be easily gelatinized. In this puffing step, foaming with hot air and/or microwaves is more preferable from the viewpoint of efficiently obtaining suitable puffed brown rice. Moreover, in this swelling process, 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, there is a high possibility that the brown rice will not be sufficiently swollen, which is not preferable. Furthermore, if the treatment temperature is higher than 280° C. or the treatment time is longer than 180 seconds, there is a possibility that the texture of the reconstituted pregelatinized dry brown rice will be adversely affected, and that the brown rice will be more likely to be scorched. I don't like it because it's expensive.

Here, the brown rice is more preferably puffed 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 puffing step. This is because the water absorbency and rice-cooking/steaming properties in the subsequent pregelatinization step are further improved, and the restorability and texture of the pregelatinized dry brown rice as the final product are further improved. If the puffed brown rice has a bulk specific gravity of more than 0.89 g/ml, it may become difficult to carry out the subsequent gelatinization step, and the puffed brown rice is puffed further, and the puffed brown rice has a bulk specific gravity of less than 0.53 g/ml. If it becomes, the texture of the resulting pregelatinized dry brown rice may not be suitable. In the present invention, the bulk specific gravity can be measured by weighing a sample into a graduated cylinder of a predetermined capacity (for example, 100 mL), measuring the mass, and determining the g/ml value.

Next, the obtained puffed brown rice is pregelatinized in the preheating soaking treatment for less than 2 hours in the pregelatinization step. In this alpha conversion step, water is added to the puffed brown rice, preferably 1 to 2.5 times, more preferably 1.5 to 2.0 times the mass of the brown rice used as a raw material. After performing a pre-heating soaking treatment at room temperature (5 to 35 ° C.) for less than 2 hours, it is heated to a temperature above room temperature, preferably 70 ° C. or higher, more preferably at a temperature of around 100 ° C. and held for 20 to 30 minutes. Then, water is absorbed into the starch of the rice due to water absorption during heating to create a swollen state. Here, this pregelatinization step can be carried out in a batch or continuous manner by a known method such as rice cooking or steaming. It is preferable that the gelatinized rice be 200 to 300% by mass, more preferably 200 to 250% by mass, based on the mass of brown rice used as a raw material. In the present invention, in order to gelatinize the puffed brown rice in which at least a part of the pericarp and seed coat is torn by the puffing step and the water absorbency has increased, in order to allow water to penetrate into the inside of the rice in the gelatinization of brown rice, it is usually It is also characterized in that it does not require long pre-heating immersion treatment at room temperature, which is necessary. In the present invention, the pre-heating immersion treatment time is set to less than 2 hours, preferably 1.5 hours or less, more preferably 1 hour or less, and most preferably not to perform the pre-heating immersion treatment. . If the pre-heating soaking treatment is performed for 2 hours or more, the rice grains are likely to break during the drying treatment, and single-grained pregelatinized dry brown rice cannot be obtained. In particular, when the swelling temperature is set high in the swelling step, it is preferable that this pre-heating immersion treatment is as short as possible.

Further, in the soaking step, the rice that has been gelatinized in the gelatinization step is soaked (post-heating soaking) in an enzyme solution containing α-amylase and adjusted to the optimum temperature for α-amylase. The immersion treatment time is preferably 2 seconds to 3 minutes, more preferably 5 seconds to 1 minute. In addition, the "immersion treatment" in this immersion process includes not only the treatment of immersing the gelatinized rice in a sufficient amount of enzyme solution for this rice (narrowly defined immersion), but also the immersion in the gelatinized rice. It also includes a treatment of spraying the enzyme solution (if necessary, allowing to stand after spraying) and a treatment of dropping the enzyme solution onto the gelatinized rice (if necessary, dropping and leaving to stand). After this immersion treatment, draining is performed. By this soaking treatment and draining, the sticky component on the surface of the gelatinized rice grains can be washed away, and the rice grains are less likely to stick together in the subsequent drying process. easier to obtain.

If the immersion treatment time is less than 2 seconds, the effect of the post-heating immersion treatment may not be sufficiently obtained. In addition, when the soaking time exceeds 3 minutes, α-amylase acts not only on the surface of the rice grain but also on the inside of the rice grain, so the texture of the reconstituted pregelatinized dry brown rice tends to deteriorate. Furthermore, the post-heating soaking treatment of the present invention requires the use of α-amylase, and the use of other types of amylase such as β-amylase does not produce the desired effect.

The amount of α-amylase used in the enzyme solution is preferably such that the α-amylase is 0.0001 to 0.002% by mass. The optimum temperature of the α-amylase to be used is preferably 35-80°C, more preferably 50-70°C. In other words, the enzyme solution is preferably adjusted to 35 to 80°C, more preferably 50 to 70°C. It is preferable that the enzyme solution is kept within this temperature range during the post-heating soaking 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 the α-amylase to be used.

In the present invention, the treatment with the enzyme solution containing this α-amylase is characterized in that it is performed on the pre-dried pre-gelatinized brown rice that has been pre-gelatinized in the pre-gelatinization step. However, even if the enzyme solution containing this α-amylase is used, the desired effect cannot be obtained.

Then, the rice soaked in the soaking step is dried in the drying step. Drying in this drying step can be performed by methods such as hot air drying, freeze-drying (FD) drying, and microwave drying. At this time, it is preferable to adjust the conditions of the rice, the heat source, etc. in the apparatus so that the drying is as uniform as possible. Hot air drying (for example, hot air drying conditions of 90 to 100° C. for 50 to 100 minutes) is more preferable from the viewpoint of preventing excessive swelling of the resulting pregelatinized dried brown rice. Furthermore, in this hot air drying, the humidity conditions may be adjusted. From the viewpoint of long-term storage stability, it is preferable to dry the resulting pregelatinized dried brown rice so that the water content thereof is 15% by mass or less.
Here, in order to pre-dry the surface of the rice grains before drying and deactivate the α-amylase attached to the surface of the rice grains, a steaming step of steaming the soaked rice in the soaking step may be performed before the drying step. good. As a result, the sticking of rice grains in the drying process can be further suppressed, and the excessive action of α-amylase can be further suppressed.

Then, the obtained pregelatinized dry brown rice may be cooled to about room temperature by standing to cool or the like, and then filled into a packaging container by a packaging and filling process. The packaging container is not particularly limited, and examples thereof include a packaging container having a bag-like, cup-like, or tray-like shape and capable of being sealed after being filled with contents.

In addition, the method for producing pregelatinized dried brown rice according to the present invention may include arbitrary steps other than the above, as long as the effects of the present invention are not significantly affected. An example of the 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 dry brown rice of the present invention obtained by the above production method and the like, the pericarp and seed coat on the surface layer are torn and at least a part of the aleurone layer is exposed. This makes it possible to restore in a short time (for example, within 5 minutes after immersion in hot water of 90 to 100 ° C.), and its digestibility is also improved. It is rich in fiber and the like, and the absorbability (nutrition absorption) of nutrient components represented by these is also enhanced. In addition, since it is single granulated and can be quickly reconstituted simply by immersing it in hot water or water, it can be reconstituted and eaten in the required amount, and can be suitably used outdoors or for emergencies.

And, as described above, the pregelatinized dried brown rice of the present invention is single-grained in a dry state and can be uniformly restored, so that the texture after restoration gives a distinct feeling of rice grains. . In the present invention, the term “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). do. This can be calculated from the mass ratio of single grains in a given amount of pregelatinized dry brown rice.

In addition, 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 hot water at 98°C (the temperature at the start of immersion is It has a water absorption of 240 to 300% by mass, preferably 250 to 280% by mass after 5 minutes of immersion in hot water of 98°C. The pregelatinized dry brown rice of the present invention having such bulk specific gravity and water absorption can be reconstituted in a short period of time with boiling water or the like, and when reconstituted, it has the original texture of cooked rice. Here, the bulk specific gravity means the value measured by the same method as described above, and the water absorption rate is the weight of the pregelatinized dry brown rice after immersing the pregelatinized dry brown rice in hot water at 98°C. It means the value expressed as a percentage of the mass ratio after minutes.
Furthermore, the pregelatinized dry brown rice of the present invention is glutinous brown rice having an amylose content in the starch of 15% by mass or more and/or pregelatinized dry brown rice using glutinous brown rice. It is preferred because it is suitable.

The pregelatinized dried brown rice of the present invention may contain any additive component within a range that satisfies the above constitution and does not significantly affect the effects of the present invention, but it does not have to contain any additive component.

Examples of the present invention will be described below, but the present invention is not limited to the following examples, and various modifications are possible within the technical concept 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 expansion step (expansion treatment) in the production of pregelatinized dried brown rice.
100 g of raw brown rice (Haenuki 50%, Tsuyahime 50%, both produced in Yamagata Prefecture) is puffed with hot air at 200 ° C. for 39 seconds, and the puffed brown rice obtained (bulk specific gravity 0.65 g / ml ) was added with 1.8 times the amount of raw 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 Thermos Co., Ltd.), and the resulting cooked rice is adjusted to about 60 ° C. with 0.05% neospirase (a preparation containing 1% α-amylase, optimally It was transferred to an enzyme solution containing Nagase Chemtex Co., Ltd. at a temperature of 60 to 70° C. and immersed with stirring for 45 seconds. After immersion in the enzyme solution, the rice was drained, and the rice after the draining was placed in a drying tray in a flat state and dried with hot air at 95° C. for 75 minutes (Comparative Example A).

On the other hand, as Comparative Example B, 100 g of the same raw brown rice was soaked in 1.8 times the amount of water at room temperature for 24 hours. The weight, bulk specific gravity and state of brown rice in each of these steps are summarized in Table 1 below. In the table, "separate from the kettle" represents the state when the cooked rice is separated from the kettle of the rice cooker, and "flattened state in the drying tray" refers to the rice that has been drained after being immersed in the enzyme solution and placed in the drying tray. represents the state when it is stretched flat, and the “loosen state after drying” represents the state when the dried brown rice on the drying tray is loosened after hot air drying (the same applies to Tables 2 and 4 described later) ).

As a result, since the brown rice of Comparative Example A, which had undergone swelling treatment before rice cooking, had extremely high water absorbency, all water was absorbed by the 24-hour immersion treatment at room temperature before rice cooking. When this brown rice was dried after cooking, the rice grains collapsed and the gelatinized dry brown rice was not obtained. Therefore, the weight after drying and the loosening state after drying could not be confirmed (ND). In addition, in Comparative Example B, in which the puffing treatment before rice cooking was not performed, the resilience of the obtained pregelatinized dry brown rice and the texture after reconstitution were not favorable.

(Preparation of pregelatinized dried brown rice 2)
Next, the following test was conducted in order to confirm the influence of the soaking time before heating in the production of pre-gelatinized dried brown rice.
100 g of raw brown rice (Haenuki 50%, Tsuyahime 50%, both produced in Yamagata Prefecture) was puffed with hot air at 200° C. for 39 seconds to obtain puffed brown rice (bulk specific gravity 0.65 g/ml). 1.8 times the amount of raw brown rice was added. Then, the immersion time before heating was 0 hours (no immersion, Example 1), the immersion time before heating was 0.5 hours (immersion 0.5 h, Example 2), and the immersion time before heating was 2 hours (immersion 2 hours, Comparative Example 1). ), and all of them were cooked with a rice cooker (microcomputer rice cooker JBG-B100, manufactured by Tiger Thermos Co., Ltd.), and each of the obtained cooked rice was adjusted to about 60 ° C. It was transferred to an enzyme solution containing 0.05% neospitase (preparation containing 1% α-amylase, optimum temperature 60-70°C, manufactured by Nagase ChemteX Corporation) and immersed with stirring for 45 seconds. After being immersed in the enzyme solution, the rice was drained, and the rice after the draining was put in a drying tray in a flat state and dried with hot air at 95° C. for 75 minutes. The weight, bulk specific gravity and state of brown rice in each of these steps are summarized in Table 2 below. In all cases, pregelatinized dry brown rice that was single-grained could be obtained.

Then, sensory evaluation was performed on each of the pregelatinized dried brown rice of Examples 1 and 2 and Comparative Example 1 thus obtained. Specifically, 30 g of the pregelatinized dried brown rice was placed in a cup-shaped container together with the soup, hot water at 98° C. was poured into the container, and after 5 minutes, the brown rice reconstituted with hot water was subjected to sensory evaluation.
The sensory evaluation was based on the following evaluation criteria for three items: resilience of pregelatinized dried brown rice (good rebound without a core in the center), texture (elasticity and stickiness), and grain texture (visual grain texture). were used to standardize the evaluation criteria among the panelists. Specifically, using Example 1 as a reference sample (evaluation is 4.0 for all items), 10 panelists compared and sensory evaluated each sample by relative evaluation based on the following evaluation criteria, and the average value was calculated. The results are shown in Table 3 below.

<Evaluation Criteria for Restorability, Texture and Rice Grain Feeling>
5: Very good (better than Example 1)
4: Somewhat good (equivalent to Example 1)
3: Good (slightly inferior to Example 1 but good)
2: Somewhat bad (inferior to Example 1)
1: Poor (considerably inferior to Example 1)

As a result, the pregelatinized dried brown rice of Examples 1 and 2 had good reconstitution properties, and also had good texture and rice grain texture. On the other hand, the pregelatinized dry brown rice of Comparative Example 1 had good restorability, but the rice grains were disintegrated, and the rice grain texture was particularly unfavorable.

(Preparation of pregelatinized dried brown rice 3)
Next, the following test was carried out in order to confirm the effect of the expansion treatment conditions on the production of pregelatinized dry brown rice.
100g of raw brown rice (Haenuki 50%, Tsuyahime 50%, both from Yamagata Prefecture) was washed to remove dirt on the surface, then heated at 150°C for 156 seconds, 175°C for 83 seconds, 200°C for 70 seconds, and 225°C. Each puffed brown rice obtained by puffing with hot air under four conditions for 52 seconds (bulk specific gravity of 0.86 g/ml, 0.74 g/ml, 0.63 g/ml, and 0.59 g/ml, respectively) 1.8 times the amount of raw brown rice was added. Then, the rice was cooked by a rice cooker (microcomputer rice cooker JBG-B100, manufactured by Tiger Thermos Co., Ltd.) without any soaking time before heating, and the obtained rice was adjusted to about 60 ° C. with 0.05% It was transferred to an enzyme solution containing neospitase (a preparation containing 1% α-amylase, optimum temperature of 60-70°C, manufactured by Nagase ChemteX Corporation) and immersed with stirring for 45 seconds. After being immersed in the enzyme solution, the rice was drained, and the rice after the draining was placed in a drying tray in a flat state and dried with hot air at 95° C. for 75 minutes (Examples 3 to 6).

On the other hand, as Comparative Example 2, 100 g of the same raw brown rice was washed, then 1.8 times the amount of water was added and immersed at room temperature for 24 hours. Brown rice was prepared. The weight, bulk specific gravity and state of the brown rice in each of these steps are summarized in Table 4 below. In all cases, pregelatinized dry brown rice that was single-grained could be obtained.

For each puffed brown rice after the puffing step in these manufacturing processes, the grain side and cross section (the cross section obtained by cutting the puffed brown rice grain in the lateral direction) were observed. Table 5 shows this observation and the bulk specific gravity of each puffed brown rice.
In addition, for each puffed brown rice after the puffing step in the manufacturing process of Examples 3, 4, and 6, the side surface and cross section of the grain were further observed under a microscope under the following conditions. compared. This micrograph is shown in FIG.
Equipment used: Digital microscope VHX-1000 (manufactured by Keyence Corporation)
Magnification: 50x

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

As a result, all of the pregelatinized dried brown rice of Examples 3 to 6 had good restoration property and excellent texture as compared to the pregelatinized dried brown rice of Comparative Example 2. In addition, when the puffing treatment temperature is increased, the bulk specific gravity of the obtained puffed brown rice tends to be smaller, and the resilience of the obtained pregelatinized dried brown rice tends to be better. When the puffing treatment temperature exceeds 200° C., the grain texture of the resulting pregelatinized dry brown rice tends to be slightly reduced. Furthermore, from the evaluation of the appearance of the puffed brown rice after the puffing process, it was clarified that at least a part of the epidermis (pericarp and seed coat) of the brown rice was torn after the puffing process in Examples 3, 4, and 6. (Fig. 2).

In addition, for the pregelatinized dried brown rice of Examples 3, 6 and Comparative Example 2, the bulk specific gravity and the water absorption rate 5 minutes after immersion in hot water at 98° C. were measured. 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 pregelatinized dried brown rice of Example 6 had a bulk specific gravity of 0.34 g/ml and a water absorption rate of was 276% by mass. On the other hand, the pregelatinized dried brown rice of Comparative Example 2 had a bulk specific gravity of 0.45 g/ml and a water absorption of 201% by mass.

(Preparation of pregelatinized dried brown rice 4)
In order to further confirm the effect of the expansion treatment conditions on the production of pregelatinized dry brown rice, the following test was carried out.
After washing 100 g of raw brown rice (Haenuki 100%, produced in Yamagata Prefecture) to remove dirt on the surface, it is expanded with hot air at 240°C for 42 seconds, 260°C for 35 seconds, and 280°C for 32 seconds. 1.8 times the amount of raw brown rice was added to each puffed brown rice obtained (bulk specific gravity of 0.58 g/ml, 0.56 g/ml and 0.55 g/ml, respectively). Then, the rice was cooked by a rice cooker (microcomputer rice cooker JBG-B100, manufactured by Tiger Thermos Co., Ltd.) without any soaking time before heating, and the obtained rice was adjusted to about 60 ° C. with 0.05% It was transferred to an enzyme solution containing neospitase (a preparation containing 1% α-amylase, optimum temperature of 60-70°C, manufactured by Nagase ChemteX Corporation) and immersed with stirring for 45 seconds. After being immersed in the enzyme solution, the rice was drained, and the rice after the draining was put in a drying tray in a flat state and dried with hot air at 95° C. for 75 minutes (Examples 7 to 9).

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

As a result, even if the puffing treatment temperature is set to 240°C, 260°C or 280°C, as the puffing treatment temperature rises, the grain texture of the resulting pregelatinized dry brown rice tends to decrease slightly, but overall the sensory evaluation is generally good. there were. However, in the swelling treatments at 260° C. and 280° C., the brown rice tended to burn slightly during the swelling treatment, and the swelling treatment time was short, so the treatment tended to be slightly uneven.

In addition, for the pregelatinized dried brown rice of Example 9, the bulk specific gravity and the water absorption after 5 minutes of immersion in hot water at 98°C were measured. The measured results for each lot produced twice by the same method were a bulk specific gravity of 0.38 g/ml and a water absorption of 259% by weight, and a bulk specific gravity of 0.35 g/ml and a water absorption of 282% by weight, respectively.

(Preparation of pregelatinized dried brown rice 5)
The following test was carried out to confirm the influence of the immersion time in the enzyme solution in the production of pregelatinized dried brown rice.
After washing 100 g of brown rice (Haenuki 100%, produced in Yamagata Prefecture) as a raw material to remove surface stains, puffing treatment is performed with hot air at 225 ° C. for 52 seconds, resulting puffed brown rice (bulk specific gravity is 0 0.59 g/ml) was added with 2.0 times the amount of raw brown rice. Then, the rice was cooked with a rice cooker (microcomputer rice cooker JBG-B100, manufactured by Tiger Thermos Co., Ltd.) without taking a soaking time before heating, and the obtained cooked rice was divided into three and adjusted to about 60 ° C. 0.05 % Neospitase (a formulation containing 1% α-amylase, optimum temperature 60-70°C, manufactured by Nagase ChemteX Corporation) and immersed with stirring for 2 seconds, 45 seconds, and 3 minutes, respectively. After being immersed in the enzyme solution, the rice was drained, and the rice after the draining was placed in a drying tray in a flat state and dried with hot air at 95° C. for 75 minutes (Examples 10 to 12).

The pregelatinized dried brown rice of Examples 10 to 12 thus obtained was subjected to sensory evaluation in the same manner 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 were evaluated favorably in all items, but the pregelatinized dried brown rice of Example 12, which was subjected to the enzyme immersion treatment for 3 minutes, was evaluated as a whole. Although the evaluation was generally good, the texture of rice grains was slightly reduced and the texture tended to be soft.

As described above, according to the method for producing pregelatinized dried brown rice according to the present invention, the pregelatinized dried brown rice that has been remarkably improved in water absorbency and rice-cooking properties, and has preferable reconstitution property and texture after reconstitution can be obtained. 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 rice (produced in Yamagata Prefecture) is used as the raw brown rice instead of the raw brown rice (Haenuki, Tsuyahime) used in this example. of pregelatinized dry brown rice can be obtained.

Claims (6)

A puffing step in which brown rice is foamed under conditions of 150 to 280° C. for 30 to 180 seconds to obtain puffed brown rice, a alpha conversion step in which the puffed brown rice is preheated for less than 2 hours, and the alpha conversion. A soaking step of soaking the rice that has been pregelatinized by the step in an enzyme solution containing α-amylase and adjusted to the optimum temperature of the α-amylase, and a drying of drying the soaked rice in the soaking step. A method for producing pregelatinized dried brown rice, comprising the steps of: 2. The method for producing pregelatinized dry brown rice according to claim 1, wherein said puffing step is a step of foaming brown rice with hot air and/or microwaves. The method for producing pregelatinized dry brown rice according to claim 1 or 2, wherein the puffed brown rice having a bulk specific gravity of 0.53 to 0.89 g/ml is obtained by the puffing step. The method for producing pregelatinized dry brown rice according to any one of claims 1 to 3, wherein the pregelatinizing step is a step of pregelatinizing the puffed brown rice after adding water to the puffed brown rice without pre-heating soaking. The method for producing pregelatinized dried brown rice according to any one of claims 1 to 4, wherein the soaking treatment time in the soaking step is 2 seconds to 3 minutes. The method for producing pregelatinized dry brown rice according to any one of claims 1 to 5, wherein the optimum temperature of the α-amylase is 35 to 80°C.

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