JPS61152251A - Production of processed unpolished rice - Google Patents

Abstract

PURPOSE:In obtaining processed unpolished rice by water immersion, steaming or boiling, pressing, and drying, to obtain processed unpolished rice which can be boiled in the same way as that of polished rice, has little collapse of grains of boiled rice, and show the same appearance as that of unprocessed unpolished rice, by allowing the unpolished rice after immersion in water to stand, making water distribution in grains of rice uniform and boiling the unpolished rice. CONSTITUTION:Water is absorbed in unpolished rice until water content reaches 25-35wt%, the unpolished rice is allowed to stand once, steamed or boiled, passed through rolls having 0.9-1.4mm gaps, pressed, and dried to give the aimed processed unpolished rice. When time for allowing the unpolished rice to stand is Yhr, and temperature for allowing it to stand is X deg.C, correlation of Y=30/X, 50<=X<=60 is preferable.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a method for cooking unprocessed brown rice that can be cooked in the same way as polished rice using an ordinary rice cooker that is widely used in households today. The present invention relates to a method for producing processed brown rice that has almost the same appearance as that of brown rice and has extremely few grains that disintegrate even when soaked in water or cooked.

(Conventional technology) Brown rice has a structure in which the periphery of the grain is covered with a strong pericarp and seed coat called the husk, making it more difficult for water to penetrate than polished rice. Therefore, when rice is cooked in the same way as polished rice, the amount of water that penetrates into the center of the grain is insufficient, resulting in swelling and
The degree of softening has not reached a level suitable for consumption. Therefore, in order to cook brown rice to a state suitable for consumption, it has traditionally been necessary to use special equipment or perform complicated cooking methods, such as using a pressure cooker or boiling it once. Met. Compared to polished rice, brown rice is less consumed than white rice even though it is rich in useful micronutrients such as B vitamins, unsaturated fatty acids, and minerals, but its ability to release the rice from cooking is one of the reasons . Therefore, a method of processing brown rice has been developed that allows it to be cooked in the same way as regular polished rice without destroying or losing most of its inherent nutrients. The currently known method involves soaking brown rice in water or salt water, draining it, heating it to make it easier to press, and passing it through rolls to crack the surface of the brown rice. After drying by heating, the surface of brown rice is quickly cooled to create cracks in the surface of brown rice due to shrinkage strain (Shokuhin Kogyo Vol. 23, No. 22, 1980, p. 33). Method for making porous
757) etc. All of these methods create cracks in the surface of brown rice to improve water absorption and allow it to be cooked in the same way as polished rice.

(Problems to be Solved by the Invention) However, although the processed brown rice obtained by the above method has a water absorbency close to that of polished rice, many of the grains have not had their outer skins cut sufficiently, so the endosperm part is In addition to the insufficient extensibility of the outer shell for the amount of expansion, many grains disintegrate during cooking. Alternatively, cracks are also formed in the endosperm, which causes the grains to disintegrate as the cracks become larger when immersed in water. .

Physical properties such as elasticity and texture are reduced in a way that is different from that of regular cooked rice. Furthermore, when disintegrated grains and whole grains coexist, the amount of water absorbed by each grain is different, resulting in cooked rice that is a mixture of hard grains and soft grains and has uneven hardness. A similar problem occurs when mixed with polished rice. As described above, there are some insufficiencies in terms of taste, and it is desired to develop an effective means to solve the above-mentioned drawbacks.

(Means and effects for solving the problems) The present invention has the following features:
From the above points of view, rice retains most of its original nutrients, has almost the same appearance as unprocessed brown rice, can be cooked in a regular rice cooker, and does not disintegrate even when soaked in water or cooked. As a result of repeated research with the aim of providing a method for producing processed brown rice with extremely few grains, we found that in the processing method of water soaking, steaming, and pressing, a certain amount of water is absorbed before steaming, and To make the distribution of water within the grains uniform to some extent
Finally, we have discovered that the above objectives can be achieved and have completed the present invention.

That is, in the present invention, brown rice is made to absorb water until the water content reaches 25 to 35% by weight, and then left to stand without being immediately heat-treated to even out the distribution of water within the brown rice grains. Soften brown rice by steaming, 0.9 to 1.411
The present invention relates to a method for producing processed brown rice, which is characterized by passing it through a pair of rolls for 1 minute to press it, and then drying it.

The present invention will be further explained below.

Raw brown rice is used as it is or after being lightly washed with water to remove foreign substances, water is permeated into the brown rice so that the water content is 25 to 35% by weight. In order to allow water to penetrate, brown rice may be soaked in water, or the required amount of water and brown rice may be mixed uniformly and allowed to penetrate. When soaking, the water absorption rate of brown rice varies greatly depending on the soaking temperature, and also varies slightly depending on the variety of brown rice, so measure the required soaking time in advance, soak for the determined time, and then drain the water. All you have to do is dehydrate. Generally, it is sufficient to dehydrate the material by immersing it at 20C for 4 to 6 hours and at 50C for about 50 to 90 minutes. Also, when mixing with the required amount of water, the added water will permeate and adhere to the brown rice and free water will disappear after approximately the same amount of time as during soaking.

From the viewpoint of nutrient retention, the immersion dehydration method causes some nutrients to be washed away, so a method of mixing brown rice with the required amount of water is preferable. On the other hand, in terms of equipment, the immersion dehydration method is simpler to implement. If the moisture content of brown rice is less than 25%, the final processed brown rice grains will collapse after soaking and cooking, making it unfit for purpose, regardless of the steaming and pressing conditions. When the ratio is 35- or more, the brown rice after steaming is severely lumped and has poor handling properties, making it impossible to carry out the subsequent pressing process.

Next, the brown rice with a predetermined amount of water is left to stand for a predetermined period of time without being immediately steamed. By doing so, the distribution of water within the grains of brown rice becomes more even. That is, immediately after absorbing a predetermined amount of water, the moisture content in the outer periphery of the brown rice flour is high, and the moisture content in the center is low, making it very uneven. When brown rice that has just absorbed a predetermined amount of water is steamed to an extent that no clumps occur and then subjected to a flattening process, the desired processed brown rice cannot be obtained under any flattening conditions.

The length of time that should be allowed to stand depends on the temperature as well as the immersion time. Ideally, the incidence of disintegrated grains after cooking should be reduced to 1% of the total grains.
It is necessary to suppress it to 5 to 20% or less, and when the standing time is Y (hours) and the standing temperature is X (C), the formula Y, 3
It is suitable for the purpose of the present invention to leave it for a time longer than 0/X, 5≦X≦60. Further, a length of 5C or less is not practical because it becomes very long. If the temperature exceeds 60C, the outer skin of the brown rice will start to soften, and lumping will occur during the next steaming process, which is not preferable. Further, if the standing time is made longer than the curve expressed by the previous equation, the effect of making the water distribution uniform increases to some extent, but as it becomes longer, the effect remains unchanged. The relationship between the storage temperature and the minimum storage time is shown in the drawing.

The purpose of the steaming process is to create cracks in the outer skin of the brown rice and to soften the brown rice to a state suitable for cutting through the following pressing process. This treatment is achieved by contacting brown rice with normal pressure or pressurized saturated steam for about 20 to 30 minutes under normal pressure. Further, it is preferable to prevent condensed water from being generated as much as possible during steaming. Partly superheated steam may be used. If the steaming time is less than 20 minutes, the softening of the brown rice will be insufficient, and if the steaming time is more than 30 minutes, starch will leak and agglomeration will occur, resulting in properties unsuitable for pressing. In this process, the time during which the temperature of the brown rice grains is around 100C is not very long, so almost no destruction of nutrients occurs.

The steamed brown rice is immediately subjected to pressing. The pressing process is carried out by passing between two rotating rolls. The spacing between the rolls is adjusted within the range of 0.9 to 1.4 cm. If the roll spacing is less than 0.9 mm, the cracks in the outer skin will be large enough, but the brown rice grains will become flat.
The appearance will be different from untreated brown rice. In addition, there are many grains that disintegrate after soaking in water and cooking, which does not meet the purpose of 9. On the other hand, if the roll spacing is wider than 1.41 mm, cracks will not form in the outer skin sufficiently, and brown rice that can be cooked in the same way as polished rice cannot be obtained. From the viewpoint of warming the brown rice grains when passing between the rolls, peeling properties from the rolls, and suppressing cracking due to compression of the endosperm, the temperature is preferably 60C or higher, preferably 7.
It is desirable to keep it above 00.

The purpose of drying after the pressing process is to remove excess water so that the processed brown rice can be stored at room temperature.

Dry until the moisture content is around 13%. An efficient dryer with less friction between brown rice grains is suitable. The drying temperature is set to 8 to prevent burning of brown rice and destruction of nutrients.
It is preferably around 5C.

The processed brown rice obtained according to the present invention has the characteristics that there is almost no destruction or loss of nutrients, that it can be cooked in the same manner as polished rice, and that there are extremely few disintegrated grains after soaking in water and cooking. Methods by heating and cooling, methods by puffing, methods by methods and conventional steaming.

Prevention of grain disintegration, which could not be achieved with the pressing method, can only be achieved by providing a treatment step to make the distribution of moisture within the brown rice grains more uniform before steaming. This is because the outer skin of brown rice has sufficient cracks) and the endosperm has almost no cracks, so the endosperm does not rupture even when soaked in water, and the outer skin expands as the endosperm expands even when rice is cooked. This is believed to be achieved by cleavage without resistance. Because of these characteristics, cooked brown rice that is uniformly soft and delicious can be obtained even when cooked normally. Furthermore, when mixed with polished rice and cooked, the resulting cooked rice has almost no discomfort found in brown rice.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 20kg of brown rice produced in 1982 (Ozora, moisture 13.5%) was soaked in 5C water for 12 hours to absorb water, and then drained using a fine mesh to make 25kg of water-absorbed brown rice (water content 30%).
) was obtained. Subsequently, this water-absorbing brown rice was left for 4.5 hours in a sealed container kept at 5C. This was heated to 2k under normal pressure.
It was steamed for 25 minutes by spraying with g/cII steam. The sample was quickly passed between two rolls having a gap of 1.2 mm to perform a pressing process. The pressed brown rice was dried with hot air at 85C until the moisture content became 13 tl) to obtain processed brown rice.

Example 2 10 kg of brown rice produced in 1982 (Nipponbare, water content 14%) was soaked at 60C for 30 minutes to absorb water, and was lightly dehydrated using a centrifugal filter to obtain water-absorbing brown rice of 12.0 kP (moisture content 27%). Subsequently, this water-absorbing brown rice was kept warm at 60C and left for 30 minutes. Thereafter, the rice was pressure steamed, pressed, and dried in the same manner as in Example 1 to obtain processed brown rice.

Example 3 Brown rice produced in 1982 (Nipponbare, moisture 14%) 100 to 3
The rice was immersed in water at 0C for 3 hours to absorb water, and was lightly dehydrated using a centrifugal filter to obtain 12.8 kp of water-absorbed brown rice (32.8% moisture). Furthermore, to prevent the water from evaporating, the temperature was 30C in a closed container.
It was left for 1 hour while keeping warm. 1 kg of this under normal pressure
/cII steam was sprayed onto the mixture and steamed for 20 minutes. The sample was quickly passed between two rolls having an interval of 1.0 mm, and pressed. The pressed brown rice was dried with hot air at 90C until the moisture content was 14% to obtain processed brown rice.

Example 4 The same brown rice as in Example 3 was water-absorbed in the same manner as in Example 3.

It was dehydrated and left in a closed container for 3 hours while keeping the temperature at 300℃. Steaming, pressing, and drying were also carried out in the same manner as in Example 3 to obtain processed brown rice.

Example 5 The same 5kl of brown rice and 1.25ky of water as in Example 1 were stirred and mixed for 60 minutes while keeping the temperature at 50C using a rotary mixer. At that time, all the water was absorbed by the brown rice. Mixing was stopped and the mixture was allowed to stand for an additional 2 hours. Thereafter, saturated steam at 150C was sprayed under normal pressure for 30 minutes of steaming treatment. Immediately, it was passed between two smooth surface rolls rotating at a constant speed with an interval of 1.4I to perform a compression treatment. After that, 85C
The processed brown rice was dried with hot air until the moisture content was 13%.

Example 6 Brown rice produced in 1982 (Koshihikari. Moisture 13%) 20
kg was immersed in 20C water for 5 hours to absorb water, and then
The rice was drained through a fine mesh to obtain water-absorbing brown rice of 25.2kp. This was kept warm at 40C in a closed container and left for 1 hour. Next, saturated steam of 1.5 k17'cr/1 was sprayed under normal pressure for steaming. Immediately after steaming, 1.21
It was passed between two rotating rolls adjusted to a spacing of 111 mm, and subjected to a pressing process. After that, 95% hot air was used to remove moisture by 1%
Processed brown rice was obtained by drying the rice until it reached 4 cm.

Comparative Experiment Example 1 Add 320% of water to processed brown rice 2001 and heat it in a home rice cooker (
Rice was cooked using a Hitachi RZ-725) and the incidence of disintegrated grains after cooking was measured. The results are shown in Table 1. Samples 1 to 4 are processed brown rice obtained in Examples 1 to 4. Samples 5 to 8 are processed brown rice obtained by steaming immediately after soaking and dehydration in Examples 1 to 4. Sample 9 is processed brown rice obtained by steaming immediately after soaking and dehydration in Examples 1 to 4. It is processed brown rice that is produced through a puffing process.

Table 1 Experimental Example 2 Comparison of Collapsed Grain Generation Rate The water absorption rates of untreated brown rice, processed rice, and polished rice were measured and compared when they were immersed in 25 water machines for 30 minutes.

The results are shown in Table 2.

Table 2 Comparative water absorption samples 4 and 6.9 are the same as the sample in Comparative Experiment Example 1.

Comparative Experimental Example 3 A sensory test was conducted on three types of cooked brown rice obtained in Comparative Experimental Example 1. The panel consisted of 16 people, and a two-point comparison method was used with the control (sample 9). The results are shown in Table 3.

Table 3 Sensory test results of cooked brown rice (effects of the invention) According to the present invention, rice can be cooked in the same way as polished rice, and the grains disintegrate after cooking are extremely small, retaining most of the nutrients originally contained in the rice. It is possible to produce processed brown rice, which provides a great deal of convenience in consuming brown rice.

[Brief explanation of drawings]

The figure is a chart showing the relationship between the leaving temperature and the shortest leaving time when brown rice is once placed in the apparatus after being made to absorb water.

Claims (1)

[Claims] 1. Brown rice is made to absorb water until the water content reaches 25 to 35% by weight, and then steamed to soften the brown rice, and 0.9 to 1.
In the manufacturing method of processed brown rice, which passes through rolls with a spacing of 4 mm and is then pressed and then dried, steaming treatment is not carried out immediately after water absorption, and the brown rice is left to stand for a while to ensure a more uniform distribution of water within the brown rice grains. A method for producing processed brown rice, which is characterized by steaming the rice after it has been boiled. 2. The relationship between the minimum time for leaving to stand and the temperature is expressed by the formula Y = 3, where the shortest time is Y hours and the temperature for leaving is X°C.
0/X, 5≦X≦60, claim 1
Method for producing processed brown rice as described in section.