JP2003088316A - Unpolished rice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain unpolished rice which has an excellent nutritive value, can readily be boiled by a home rice cooker and is low-allergenized, especially low-allergenized unpolished rice suitable as a meal for a rice allergic patient. SOLUTION: This low-allergenized unpolished rice for a meal for a rice allergic patient is obtained by subjecting unpolished rice to germination treatment. This method for producing low-allergenized unpolished rice comprises subjecting unpolished rice to hydration treatment, then subjecting the hydrated unpolished rice to germination treatment until γ-aminobutyric acid content reaches about 10-30 mg/100 g and then subjecting the germinated unpolished rice to wet-heat treatment. The germinated unpolished rice has total protein content not different from those of unpolished rice and polished rice, has slight soluble protein, low reactivity with an antibody against rice allergen and extremely slight allergen. Allergen proteins of 14-16 kDa belonging to albumin fraction and 26 kDa belonging to globulin fraction being main allergen proteins of rice can be removed or reduced by the method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to low allergen brown rice which has excellent nutritional value and can be easily cooked with a domestic rice cooker, and a method for producing the same. In particular, the present invention relates to brown rice with a reduced allergen suitable for the diet of rice allergic patients.

[0002]

2. Description of the Related Art Food allergy causes hypersensitivity immune response upon the intake of a specific food, and exhibits symptoms such as allergic rhinitis, eczema, urticaria, diarrhea, migraine, and dyspnea. In recent years, attention has been paid to the development of allergic dermatitis due to grains such as rice and wheat among food allergies. In particular, rice and wheat, which are ingested in large amounts as staple foods, have not been able to take measures against them, and in many cases have become intractable, which is a serious problem. Regarding the treatment of food allergies, in addition to symptomatic treatment by the use of drugs, diet therapy that removes foods causing allergies from the patient's diet as much as possible is adopted. However, it is very difficult to remove grains, which are staple foods such as rice and wheat, and various restrictions are imposed not only on the patient but also on the family. Conversely, the stress causes worsening of the skin rash. There is also the current situation.

Further, cereals and the like from which allergens have been removed have been developed. For example, in the case of rice, allergens are water-soluble, so that water swollen and swollen is often washed with water or further treated with proteolytic enzymes. Techniques for removing allergens by methods such as
2-167040, JP 9-224592, JP 9-4723
8, JP 10-150935 JP, JP 11-115, JP 11-9
202, etc.). Although such a method of eluting and decomposing allergens is one of the solutions for lowering the allergen, there are problems such as incomplete elution and the appearance and taste of the finished low-allergenized rice. Furthermore, due to a special manufacturing method, it has become a very expensive food for daily use as a final product.

On the other hand, there is known a method of suppressing the allergen synthesis by modifying a gene on the rice chromosome or controlling its expression, and a technique relating to the rice allergen gene and the cDNA of the allergen is also known. (Japanese Patent Laid-Open No. 4-117287). However, it is difficult to completely suppress the expression of the allergen, and moreover, the safety of genetically modified foods has been taken into consideration, and there is a problem that it is difficult to permeate the rice widely as safe rice. is there.

[0005]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide safe brown rice which has reduced allergens as a staple food for rice allergic patients, and has excellent nutritional value and rice cookability.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that it is possible to easily reduce allergens by performing a series of treatments for germination of brown rice. It was That is, the present invention is a hypoallergenic brown rice characterized by being obtained by germination treatment of brown rice, α
Degree of chemical conversion is 10-50%, salt-soluble protein content is 0.7g /
The low allergen brown rice of 100 g or less and the low allergen brown rice for meal of rice allergic patients, and by hydrating brown rice with γ
-A method for producing low allergen-free brown rice, which is characterized by comprising performing a germination treatment to an aminobutyric acid content of about 10 to 30 mg / 100 g and then subjecting it to wet heat treatment.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The germination treatment in the present invention is usually carried out by immersing brown rice in warm water of a constant temperature for a predetermined time to perform a water-containing treatment to sufficiently absorb water and then drain it.
This is a treatment in which brown rice that has absorbed water is left under constant temperature conditions until the swelling of the germ or the appearance of buds can be confirmed. Specifically, for example, brown rice as it is, or a part of the brown rice is polished by a rice polishing machine or a non-washing rice machine to peel and tear,
The obtained brown rice is usually washed about 2 to 4 times, drained and then immersed in a germination tank (germination tank). Waxing can also be performed in a step after immersion. The brown rice is preferably 95-9
It is better to refine the content to 9.8% by mass, more preferably 97 to 99% by mass. By doing so, it is possible to remove foreign substances and microorganisms adhering to the epidermis of the raw brown rice, and to reduce the amount of water used for washing rice. In addition, since the degree of hakusei affects the water absorption rate and germination rate of germinated brown rice,
It is preferable to set in consideration of this point as well. Water used for washing rice is tap water, distilled water, well water, acidic water, electrolytic saline,
Any water that can be used for food such as water in which ozone is dissolved can be used.

The germination tank is usually immersed at 20 to 50 ° C.
Soak in warm water until germination, or for example 3
There is a method of soaking for about 5 hours, then dehydration, intermittent watering, and germination under a high humidity condition for a predetermined time. The hot water to be used can be exemplified by the water exemplified in the above rice washing step, and any water can be used as long as it can be used for food. Aeration may be performed continuously or intermittently in the dipping process.

The degree of germination is generally such that a bulge of about 0.5 mm to 2.0 mm, a protrusion or a bud can be confirmed from the embryo part. The optimum germination condition is that the content of γ-aminobutyric acid in brown rice reaches 10 to 30 mg / 100 g. γ-Aminobutyric acid is produced from L-glutamic acid by glutamate decarboxylase, and γ-aminobutyric acid increases with the decrease of free glutamate (chemistry and organisms, 3
3, 211, 1995). γ-aminobutyric acid content is 10m
If it is less than g / 100g, the germination state is insufficient, and the effect of reducing allergen is weak, and if the germination treatment is performed until it exceeds 30mg / 100g, there is a problem that the off-flavor of rice easily occurs, and the taste is poor become worse. After germination, the germination is stopped by heating, and the method may be steaming, or temperature treatment or drying by an appropriate method such as hot air, microwave, or cooling.

The degree of gelatinization shown in the present invention is an excellent method for discriminating between gelatinized starch and raw starch or aged starch. The α-amylase pullulanase method (BAP method).
It is the value measured by. In order to control to a desired degree of α-formation as low allergen-free brown rice, a moist heat treatment is applied to
The degree of chemical conversion is preferably about 10 to 50%,
More preferably, it should be about 15-40%. In particular, the moist heat treatment makes the allergen reduction effect remarkable. If the degree of gelatinization is less than 10%, the effect of reducing allergen is weak, and if it exceeds 50%, the shape of rice is broken, and the taste and appearance during cooking are deteriorated. The moist heat treatment mentioned here is a method of heating an object in a high humidity atmosphere, for example, an atmosphere having a humidity of 60% or more, using saturated steam, hot water, superheated steam, or the like as a heat medium. In this case, a method of heating the object to be heated by directly contacting it with a heating medium, for example, a humidity of 60%
Either of the above-mentioned atmosphere and the method of heating by indirectly contacting the heat medium like the conduction heating method can be carried out.

The specific conditions are, for example, that the vapor temperature is 98 to 180 ° C. and the treatment can be performed for 3 seconds to 30 minutes. When the steam temperature is 98 ° C. or lower, there is no problem in the α-formation and the drying itself, but the time required for the desired α-formation becomes long, and therefore it is not so preferable in the case of industrial mass production. On the other hand, if the temperature exceeds 180 ° C, there is a problem that the gelatinization proceeds too much, and the drying finish and the dipping time are limited,
The taste of cooked rice becomes poor after long-term immersion. If the treatment time is less than 3 seconds, the degree of α-formation of grains may be uneven, but it is difficult to control in the actual process. Also, if the processing time exceeds 30 minutes, gelatinization of germinated brown rice will proceed too much,
Since grain swelling occurs, brown rice grains are likely to disintegrate when blended with white rice and immersed for a long time.

As a method other than the wet heat treatment described above, a method using steaming treatment of rice, which is carried out in cooked rice production or fermentation industry, can be exemplified. For example, germinated brown rice is 0.1-7.0 kg / cm ² , preferably 0.1-2.
It is advisable to perform steaming treatment for 3 seconds to 30 minutes, preferably 10 seconds to 30 minutes under the condition of 0 kg / cm ² . Here, when the vapor pressure is less than 0.1 kg / cm ² , the effect of the present invention is weak, and the same is true when the treatment time is less than 3 seconds. On the other hand, if the treatment time is too long, the gelatinization tends to proceed too much, the taste when cooked with white rice and grain blocking are likely to occur, and the handling in the drying step tends to become poor.
On the other hand, even if the vapor pressure exceeds 7.0 kg / cm ² , the effect of the present invention can be obtained, but the pressure is too high and there is a problem in safety.

The germinated and moist-heated brown rice usually contains about 30 to 35% of water, so from a hygienic point of view, it is heat-sterilized and then aseptically packed or the brown rice has a water content of 15%. %, But it is more preferable to dry in view of storage stability, distribution, handling in processed food applications, and the like.

The brown rice thus obtained has a total protein content of 6.0 to 13.0 g / 100 g and a salt-soluble protein content of 0.7 g / 100 g or less, more preferably a salt-soluble protein content of 0. It is 0.5 g / 100 g or less. Within this range, it varies depending on the protein content of brown rice used as a raw material. In particular, the amount of salt-soluble protein in which allergen is present fluctuates due to continuous supply or intermittent supply of water during the dipping process of brown rice, and also due to aeration.
Further, in the present invention, the wet heat treatment is performed after the immersion / germination treatment, so that the content of soluble protein containing allergen is reduced, and brown rice more suitable as a staple food for rice allergic patients can be obtained.

In the present invention, the total protein amount is based on the Kjeldahl method used as a general protein quantification method, and the amount of nitrogen is measured to obtain a nitrogen-protein conversion coefficient of 5.9.
It is the value converted by 5. In the case of alkali extraction with 0.1 N NaOH and quantification by the Lowry method or the like, the brown rice obtained in the present invention is gelated, and the measured value tends to be high, which is not suitable for analysis. The amount of salt-soluble protein is the amount of soluble protein (allergen-containing protein) extracted from each rice sample with 1 M NaCl and quantified by the Lowry method.

[0016]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 Brown rice (Hoshinoyume) was immersed in constant temperature water at 25 ° C. for 5 hours, then drained, and allowed to germinate in the gas phase for 13 hours at room temperature.
Alpha degree 13%, salt-soluble protein 0.65g / 100g,
Germinated brown rice with a water content of 31.5% and γ-aminobutyric acid 19 mg / 100 g was obtained. Example 2 Brown rice (Hoshinoyume) was immersed in constant temperature water at 25 ° C. for 5 hours, then drained and allowed to undergo gas phase germination at room temperature for 10 hours.
After soaking and germination, moist heat treatment at 100 ° C for 4 minutes,
Alpha degree 24.3%, 0.3g salt-soluble protein / 100
g, water content 34.8%, γ-aminobutyric acid 18 mg / 10
0 g of germinated brown rice was obtained. Example 3 Brown rice (Hoshinoyume) was dipped in constant temperature water at 25 ° C. for 5 hours, then drained and allowed to undergo gas phase germination at room temperature for 10 hours.
After soaking and germination, heat-moisture treatment at 100 ° C for 6 minutes,
Subsequently, the mixture was fluidized and dried in a fluidized bed dryer at 100 ° C. for 20 minutes to obtain a gelatinization degree of 39.8% and a salt-soluble protein content of 0.17 g /
100 g, water content 11.3%, γ-aminobutyric acid 20 mg
/ 100 g of dry germinated brown rice was obtained. Example 4 Brown rice (Hoshinoyume) was immersed in constant temperature water at 25 ° C. for 5 hours, then drained and allowed to germinate in the gas phase at room temperature for 13 hours.
After soaking and germination, moist heat treatment at 100 ° C for 4 minutes,
Subsequently, the mixture was fluidized and dried in a fluidized bed dryer at 100 ° C. for 20 minutes to give a degree of gelatinization of 28.7% and a salt-soluble protein content of 0.4 g / 1.
00g, water content 15.5%, γ-aminobutyric acid 23mg /
100 g of dry germinated brown rice was obtained.

Comparative Example 1 Salt-soluble protein: 1.7 g / 100 g, water content: 15%,
Comparative Example 1 was 7 mg of γ-aminobutyric acid / 100 g of unpolished brown rice (Hoshinoyume). Comparative Example 2 The brown rice of Comparative Example 1 was subjected to a polishing treatment, and the salt-soluble protein was 0.9.
6g / 100g, water content 14%, γ-aminobutyric acid 3m
Comparative example 3 using g / 100 g of white rice (wax sperm yield 90%)
And

Test Example 1 [Comparison of salt-soluble protein (fraction containing allergen)] 1M NaC from brown rice obtained in Examples 1 to 3 and Comparative Example 1
Soluble protein (allergen-containing protein) was extracted with 1 and subjected to SDS-polyacrylamide gel electrophoresis, and CB
B staining was performed and the staining intensity was compared. The results are shown in Fig. 1.
In SDS-PAGE analysis of the salt-soluble fraction, a slight decrease in 14-16 kDa protein was confirmed in Example 1. Further, with respect to the brown rice obtained in Examples 2 and 3 in which brown rice was soaked / germinated and then subjected to heat-moisture treatment, the 14-16 kDa allergen reduction was remarkable, and the 26 kDa allergen reduction effect was also confirmed.

Test Example 2 The brown rice obtained in Example 4 and Comparative Examples 1 and 2 was subjected to a test,
Salt-soluble proteins were extracted from each sample with 1 M NaCl and total proteins with 1% SDS / 1% 2-ME. The protein contained in each extract was detected by SDS-PAGE, and the 14-16 kDa allergen was detected by immunoblot using a monoclonal antibody. ○ Total protein mass Quantify by Kjeldahl method. The sample is pretreated according to a conventional method, rice protein is collected as ammonia gas, and the nitrogen (%) calculated from the neutralization titration value is multiplied by a coefficient of 5.95 to obtain the total protein content of rice. -Salt soluble protein (allergen-containing protein) amount 1M NaCl soluble protein (allergen-containing protein)
Is extracted and quantified by the Lowry method. 1M NaCl
The 1-fraction is operated according to a conventional method so that the Folin phenol reagent is colored by the protein and the absorbance at 750 nm is measured to determine the salt-soluble protein content of rice. Allergen protein content of molecular weight 14-16 KDa, 26 kDa The 1M NaCl fraction is subjected to SDS-polyacrylamide gel electrophoresis, stained, and the staining intensity is compared by a densitometer. ○ Rice allergen protein content After SDS-polyacrylamide gel electrophoresis, the protein of the 1M NaCl fraction and a monoclonal antibody against the rice allergen protein are allowed to bind and develop color by Western blotting, and the staining intensity is compared by a densitometer. ○ Reactivity with antibody to rice allergen The reactivity of the protein of the 1M NaCl fraction with the monoclonal antibody to the rice allergen protein is examined by the ELISA method. The allergen protein on the wells is bound with an antibody to develop color, and the absorbance at 492 nm is measured. The results are expressed as relative values converted per 100 g of particles.
The results are shown in Table 1.

[0020]

[Table 1]

[0021]

As is apparent from Table 1, the germinated brown rice of the present invention has the same total protein content as brown rice and polished rice, but has a small amount of salt-soluble protein and low reactivity with an antibody against rice allergen. , Allergen is extremely low. The major rice allergen proteins highly reactive with the specific IgE antibody in the serum of rice allergic patients include 14-16 kDa belonging to the albumin fraction and 26 k belonging to the globulin fraction.
Da is known, and it is necessary to remove or reduce these in developing rice for use in rice allergy patients. According to the present invention, brown rice is germinated,
Furthermore, by heat-moisture treatment, effectively 14-16kD
It is possible to remove or reduce the a, 26 kDa allergen protein.

[Brief description of drawings]

FIG. 1 is a drawing-substitute photograph of SDS-PAGE of salt-soluble proteins in brown rice.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hajime Kashio             6-9-1, Shin-ei, Naka-ku, Nagoya-shi, Aichi (72) Inventor Aya Mizuguchi             Kanagawa Prefecture Toyama City Totsuka Ward Shinano 12-13 shares             FANCL Central Research Institute (72) Inventor Mitsuo Kise             Kanagawa Prefecture Toyama City Totsuka Ward Shinano 12-13 shares             FANCL Central Research Institute (72) Inventor Hiromichi Aoto             Kanagawa Prefecture Toyama City Totsuka Ward Shinano 12-13 shares             FANCL Central Research Institute (72) Inventor Kenichi Ishiwata             Kanagawa Prefecture Toyama City Totsuka Ward Shinano 12-13 shares             FANCL Central Research Institute F-term (reference) 4B018 LB10 MD50 ME07 MF14                 4B023 LC09 LE01 LG03 LP20                 4B025 LT09

Claims (4)

[Claims] 1. A brown rice having a reduced allergen, which is obtained by germinating brown rice. 2. The hypoallergenic brown rice according to claim 1, which has a degree of gelatinization of 10 to 50% and a salt-soluble protein content of 0.7 g / 100 g or less. 3. The hypoallergenic brown rice according to claim 1, which is used for meals of rice allergic patients. 4. A hypoallergen-reducing method according to claim 1, 2 or 3, which is obtained by subjecting brown rice to a hydrous treatment to give a γ-aminobutyric acid content of about 10 to 30 mg / 100 g, followed by a moist heat treatment. How to make brown rice.