JP6061818B2 - Brown rice flour - Google Patents

Description

  The present invention relates to brown rice flour that can suppress the blue odor of brown rice and is suitable for bread and sponge cake.

  Brown rice contains functional components such as GABA (γ-aminobutyric acid), β-glucan, and γ-oryzanol, and contains more ferulic acid than polished rice. Brown rice contains more vitamins, minerals and dietary fiber than polished rice, and brown rice is said to have higher nutritional value than polished rice.

  Therefore, the development of brown rice flour suitable for the manufacture of foods such as bread is important. However, brown rice flour has a finer grain size and lower starch damage. However, the degree of damage of brown rice powder obtained by grinding unpolished rice without any treatment exceeds 6%.

  For this reason, brown rice flour for bread is proposed in which brown rice is dipped in water for 12 hours or longer and then milled by a vortex crusher (super powder mill) (see Patent Document 1).

  In addition, a method has also been proposed in which brown rice is washed and hydrated, and then coarsely crushed into 2 to 4 parts, and the crushed brown rice is further hydrated and tempered (see Patent Document 2). ).

  However, the conventional brown rice flour has a problem that it has a characteristic blue odor (old rice odor) due to enzymatic degradation of lipid contained in the rice bran portion by lipase or lipoxygenase.

  In addition, when the brown rice is immersed in water for 12 hours or more, there is a problem that germs propagate.

JP 2012-10660 A JP 2012-50378 A

  It is an object of the present invention to provide brown rice flour having a fine particle size, a low starch damage degree, and eliminating the blue odor of brown rice, which can be used for bread and sponge cake with no habit and volume. And

The present inventor obtains brown rice powder having a desired particle size, starch damage degree, and reduced increase in the degree of fatty acid formation over a long period of time by pulverizing brown rice in warm water at a constant temperature for a fixed time. And found the present invention. That is, the present invention is as follows.
<1> In the present invention, the starch damage degree is 4% or less, the average particle size of the endosperm tissue is 100 μm or less, the inside environment is 45 ° C., and the humidity is constant 40%. Brown rice flour having a fatty acid content of 100 mg KOH / 100 g or less.
<2> Furthermore, the present invention is the method for producing brown rice powder according to claim 1, wherein the brown rice is immersed in warm water for a time to satisfy the following formulas (1) and (2), and the soaked brown rice is pulverized.
−0.1x + 6.8 <y <−0.1x + 9.2 Expression (1)
49 <x <61 Formula (2)
In the above formulas (1) and (2), x is temperature (° C.), and y is immersion time (hr).
<3> Furthermore, the present invention is the method for producing brown rice flour according to claim 2, wherein the pulverization is performed by an impact pulverizer or an airflow pulverizer.

  The brown rice flour of the present invention is a brown rice flour having a fine particle size, a low starch damage degree, and eliminating the blue odor of brown rice, and enables bread and sponge cake having no habit and volume.

(About the brown rice flour of the present invention)
The brown rice flour of the present invention has a starch damage degree of 4% or less, an endosperm tissue average particle size of 100 μm or less, and a fatty acid degree of 100 mg KOH after being sealed in a thermostatic oven at a temperature of 45 ° C. and a humidity of 40% for 15 days. / 100 g or less.

  The brown rice flour of the present invention has a starch damage degree of 4% or less. Brown rice flour suitable for bread and sponge cake is desirable because the lower the starch damage, the higher the volume. Normally, brown rice flour has a reduced breading aptitude when the starch damage level is 4% or more, but the general brown rice powder has a damage level of over 6%.

  In the brown rice flour of the present invention, the average particle size of the endosperm tissue is 100 μm or less, more preferably 75 μm or less. If the average particle size of the endosperm portion of the brown rice powder used for bread or sponge cake is 100 μm or more, the texture of the inner layer becomes coarse, and the texture is not preferable. In the present invention, there is a negative correlation in a certain range between the particle size of the endosperm part (rice flour) particles and the degree of starch damage. When the crushing strength is increased to produce fine particles, the degree of starch damage increases. . In view of bread-making properties, the degree of starch damage is essential, and if the crushing strength is suppressed in order not to raise this, the average particle size of the endosperm tissue will eventually be 100 μm or less, more preferably 75 μm or less. .

  The brown rice flour of the present invention is specified with respect to the average particle size of the endosperm tissue, and the particle size of the buttocks is not particularly limited, but the grain size of the buttocks in the brown rice flour of the present invention is 0.2 to 1 mm.

  The weak point of the conventional brown rice flour has a peculiar blue odor (old rice odor), and this blue odor is expressed by enzymatic degradation of lip lipids and lipase. The brown rice flour of the present invention has a fatty acid content of 100 mg KOH / 100 g or less after being stored in a thermostatic oven with a constant temperature of 45 ° C. and a humidity of 40% in a nylon poly wrapping material for 15 days under light-tight sealing conditions. Brown rice flour with a fatty acid content of 100mgKOH / 100g or less after storage under the above conditions is a packaging material in which the room temperature is constant at 25 ° C and the humidity is 40-70%, the individual packaging is nylon poly, and the outer packaging is cardboard The blue odor does not occur even after 6 months. It is considered that the enzymes were deactivated by the immersion treatment at 50-60 ° C.

  Brown rice is made by removing rice husks from rice straw and has a cocoon layer and germs, so it has a high nutritional value, but it is more likely to contain germs than polished rice. The brown rice flour of the present invention had a reduced number of general viable bacteria compared to the brown rice flour pulverized without the immersion treatment.

(Method for producing brown rice flour of the present invention)
The brown rice used in the brown rice flour of the present invention is not particularly limited, but brown rice having an amylose content in the range of 15 to 35% is preferable in terms of processing suitability when processed into bread and sponge cake and the taste of processed products. Specifically, any varieties that are distributed as edible or feed glutinous rice are in this range and can be used. On the other hand, brown rice flour containing glutinous rice without amylose as a raw material is not preferable because bread and sponge cake do not swell and the texture is like rice cake.

  The brown rice is preferably subjected to foreign matter removal as a pretreatment by a color sorter or the like.

  The pretreated brown rice is immersed in warm water of 49-61 ° C. for a time that satisfies the following formulas (1) and (2), where x is temperature (° C.) and y is immersion time (hr). .

−0.1x + 6.8 <y <−0.1x + 9.2 Expression (1)
49 <x <61 Formula (2)

  The immersion treatment is performed using a circulating thermostatic water bath so that the whole brown rice grains are completely immersed in warm water. The water to be used is not particularly limited, and general tap water can be used.

  The brown rice after the immersion treatment is crushed after dehydration treatment. The method for the dehydration treatment is not particularly limited as long as it can remove excess water remaining on the surface of the brown rice grains.

  The pulverization method is not particularly limited, but it is preferable to use an impact pulverizer for bread making because it is easy to adjust the desired particle size and starch damage degree. For the sponge cake, it is preferable to use an airflow type pulverizer because the heel portion becomes fine. The degree of pulverization can be obtained by adjusting the number of revolutions of the pulverization unit, the amount of raw material supplied, and the like, thereby obtaining a desired particle size and starch damage degree.

The contents of the present invention will be described more specifically based on the following examples.
(Examples 1-6, Comparative Examples 1-7)
<1. Property investigation of brown rice flour>
As Examples 1-6 and Comparative Examples 1-7, brown rice (variety: Hinohikari, produced in 2011, produced in Fukuoka Prefecture) was used.

  200g of each of the above brown rice is put into a net basket, and the immersion time is 1 hour, 2 hours, 3 hours and 4 hours in immersion water in each constant temperature bath at 40 ° C, 50 ° C and 60 ° C, respectively. went. Table 3 shows the classification of the examples and comparative examples of each treatment. In addition, the immersion time 0 hour in Table 1 shows the brown rice which is not immersed (Comparative Example 1).

  About the brown rice immersed in the immersion water of each said temperature for each time, after removing excess water | moisture content with a paper waste cloth, one part was used for the moisture measurement. The moisture was measured by a normal pressure drying method at 135 ° C. for 1 hour. The remaining soaked brown rice was pulverized with a high-speed rotary impact hammer mill (trade name: Laboratory Mill 3100, manufactured by Terpene) to obtain brown rice flour. The brown rice was dried by blowing hot air generated by a dryer from the raw material supply port of the laboratory mill at the same time as pulverization, and dried so that the moisture value of the brown rice flour was within the range of 13.0 ± 0.5%.

  The evaluation of the brown rice flour obtained above was performed by measuring the φ212 μm sieving ratio (φ212 μm through%), the starch damage degree, and the particle size distribution of the pulverized product classified under the sieve with a standard sieve of φ212 μm. The results are shown in Table 2.

  The starch damage degree was measured by the following method using Starch Damage Assay Kit (Megazyme). Weigh 100 mg of brown rice flour in a test tube, add 1 ml of α-amylase solution (50 U / ml), and react at 40 ° C. for 10 minutes. The reaction is stopped by adding 8 ml of a sulfuric acid solution (0.2% V / V), and then centrifuged at 3000 rpm for 5 minutes. Transfer 0.1 ml of the centrifugal supernatant to a new tube, add 0.1 ml of amyloglucosidase solution (2 U / ml), and react at 40 ° C. for 10 minutes. Next, add 4 ml of GOPOD reagent and react at 40 ° C for 20 minutes. The absorbance of the reaction solution was measured at a wavelength of 510 nm. About the measurement result, the starch damage degree was computed using following formula (3) as described in the instruction manual of Starch Damage Assay Kit. The absorbance of the blank was the same as that except that 0.1 ml of ultrapure water was added instead of the centrifugal supernatant.

Starch damage (%) = (absorbance of sample−absorbance of blank)
× (Absorbance of 150 ÷ 150μg / ml glucose standard solution) × 8.1 Formula (3)

  The particle size distribution was measured with a laser diffraction type particle size distribution measuring device (trade name Mastersizer 2000, manufactured by Malvern). The average particle diameter was D [4,3] volume average diameter.

<2. Effect of soaking temperature and soaking time on fatty acid content and blue odor of brown rice flour>
(Fatty acidity survey 1)
The brown rice flours of Examples 1 to 6 and Comparative Examples 1 to 7 were stored in a light-tight sealed container in a thermostat having a temperature of 45 ° C and a constant humidity of 40%, and the fatty acid degree was measured over time. Fatty acid degree is used as an index indicating the degree of lipid oxidation, and has a positive correlation with the intensity of blue odor of brown rice or brown rice flour.

  The fatty acid degree was measured according to a standard measurement method (Ministry of Agriculture, Forestry and Fisheries). The results are shown in Table 3. The unit of fatty acid degree in Table 3 is mgKOH / 100g.

  The blue odor was subjected to a sensory test and evaluated according to the following four levels. ◎: No blue odor is felt at all, ○: Blue odor is slightly felt, △: Blue odor is felt, ×: Blue odor is strongly felt The results of the sensory test are shown in Table 4.

(Fatty acidity survey 2)
Brown rice varieties in unpolished rice flour of Example 5 of Fatty Acid Content Survey 1: The same treatment as in Example 5 (submerged at 60 ° C. for 2 hours, except for using Haenuki (produced in Yamagata Prefecture) produced in 2011 instead of Hinohikari ) And the brown rice flour obtained by the production process, the change over time in the fatty acid degree in a general storage state was measured (Example 7). In addition, the brown rice varieties in the brown rice flour of Comparative Example 1: Brown rice obtained by the same treatment (immersion time 0 hour) and production process as in Comparative Example 1 except that 2011 Haenuki (Yamagata Prefecture) was used instead of Hinohikari. The flour was measured for changes in fatty acid content over time in a general storage state (Comparative Example 8).

  As the general storage state, the packaging was stored in a nylon-poly packaging material and a cardboard packaging material in a test room where the room temperature was kept constant at 25 ° C. and the humidity was controlled at 40-60%. About the measurement of fatty acid degree, and the blue odor, it carried out similarly to the said fatty acid degree investigation 1. Table 5 shows the measurement results of the fatty acid degree, and Table 6 shows the sensory test results of the blue odor.

<3. Bacteria count of brown rice flour>
Since brown rice is obtained by removing rice husks from rice husks by threshing, it is generally more likely that bacteria are attached as compared to polished rice. Therefore, the number of adhered bacteria was investigated for the brown rice flours of Examples 1 to 6 and Comparative Examples 1 to 7.

  The investigation of the number of adherent bacteria was performed by the Petrifilm method (manufactured by Sumitomo 3M, trade name AC plate viable count measurement). The results are shown in Table 7.

<4. Discussion of results>
(1) About the results in Table 2 The lower the starch damage degree, the better the bread-making properties. The brown rice flour of the present invention has a starch damage degree of 4% or less, but when the immersion temperature is 40 ° C, the immersion time is 2 In the range of time to 4 hours, when the immersion temperature is 50 ° C., the immersion time is in the range of 2 hours to 4 hours, and when the immersion temperature is 60 ° C., the starch damage is in the range of 1 hour to 3 hours. The degree was 4% or less.

  Although the grain size of the brown rice flour of the present invention is 100 μm or less, the grain size of the brown rice flour is any temperature of 40 to 60 ° C. and the immersion time is 1 hour to 4 hours. Was 100 μm or less.

(2) About the results of Table 3, Table 4, Table 5, and Table 6 As a weak point of brown rice flour, there is a peculiar blue odor (old rice odor). This blue odor is produced by enzymatic degradation of the lipids in the nuka part by lipase and lipoxygenase. Therefore, the blue odor can be quantified to some extent by measuring the degree of fatty acid. The brown rice flour of the present invention has a fatty acid content of 100 mg KOH / 100 g or less after being stored in a light-tight sealed storage for 15 days in a constant temperature oven with a temperature of 45 ° C. and a constant humidity of 40%. At 40 ° C., the fatty acid content after storage for 15 days under light-shielding exceeded 100 mgKOH / 100 g at any immersion time. On the other hand, when the immersion temperature was 50 ° C. and 60 ° C., the fatty acid degree after the light-tight sealed storage for 15 days was 100 mgKOH / 100 g or less at any immersion time.

  Also, from the results in Table 4, when the fatty acid degree is 50 mg KOH / 100 g or less, no blue odor is felt, 50-100 mg KOH / 100 g feels a slight blue odor, and 100-150 mg KOH / 100 g clearly shows a blue odor. It was a result to feel.

  Tables 5 and 6 show the long-term changes in fatty acid content of brown rice flour. In Comparative Example 8 (unimmersed treatment), the fatty acid content was 145.9 mgKOH / 100 g after 74 days from treatment. A blue odor was generated. On the other hand, in Example 7 (immersion temperature: 60 ° C., immersion time: 2 hours), the fatty acid degree was 75.7 mgKOH / 100 g even after 200 days from the treatment, and a slight blue odor was felt.

(3) About the result of Table 7 Since brown rice peels rice husks from rice straw, and has a straw layer and an embryo, generally, there is a high possibility that general living bacteria exist compared to polished rice. From the results of Table 7, the immersion temperature is reduced as compared with Comparative Example 1 (non-immersion treatment) at any temperature of 40-60 ° C. and at any immersion time of 1 hour to 4 hours. However, the relationship between the immersion temperature and time was not clear. This is because brown rice is immersed in a circulating thermostat, so that the bacteria present on the surface of the brown rice grains are washed away during the immersion, and that the bacteria are removed by dehydration after the immersion. It was thought that drying with hot air during pulverization might have affected the decrease in the number of bacteria.

(4) Integration of each result In summary, when the immersion temperature is 40 ° C., the fatty acid degree after light-shielding sealed storage for 15 days is 100 mgKOH at any immersion time of 1 to 4 hours (Comparative Examples 2 to 5). / 100g exceeded and was inappropriate. When the immersion temperature was 50 ° C., the starch damage degree exceeded 4% when the immersion time was 1 hour (Comparative Example 6), but it is considered that the integrated immersion time and temperature were insufficient. On the other hand, when the immersion temperature was 60 ° C., the starch damage degree exceeded 4% when the immersion time was 4 hours (Comparative Example 7), but when the immersion temperature was 60 ° C. and the immersion time was 4 hours, the accumulated immersion time was・ It is thought that gelatinization occurred in a part of starch due to excessive temperature.

  On the other hand, in the treatment satisfying any of the conditions of starch damage degree, average particle size, and fatty acid degree, when the immersion temperature is 50 ° C., the immersion time is 2 hours to 4 hours (Examples 1 to 3), and the immersion temperature is 60 ° C. The immersion time was 1 hour to 3 hours (Examples 4 to 6).

  The brown rice flour of the present invention is a brown rice flour having a fine particle size, a low starch damage degree, and eliminating the blue odor of brown rice, enabling a bread and sponge cake having no habit and volume, New applications can be developed.

Claims (3)

  Fatty acid degree after storage for 15 days in a light-sealed sealed oven in a thermostat with a starch damage degree of 4% or less, an endosperm tissue average particle size of 100 μm or less, and a temperature of 45 ° C. and a constant humidity of 40%. Is brown rice flour. Fatty acid degree after storage for 15 days in a light-sealed sealed oven in a thermostat with a starch damage degree of 4% or less, an endosperm tissue average particle size of 100 μm or less, and a temperature of 45 ° C. and a constant humidity of 40%. A method for producing brown rice flour,
Brown rice in hot water, and immersion time that satisfies the following formulas (1) and (2) The method of Xuan rice flour you grinding the soaked rice.
−0.1x + 6.9 <y <−0.1x + 9.1 Expression (1)
49 <x <61 Formula (2)
In the above formulas (1) and (2), x is temperature (° C.), and y is immersion time (hr). The method for producing brown rice flour according to claim 2, wherein the pulverization is performed by an impact pulverizer or an airflow pulverizer.