JP2018038368A - Method for producing gelatinized starch powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing gelatinized starch powder, when raw material grains are charged to a heating shear pulverization machine and are pulverized to produce gelatinized starch powder, under the mass-production condition where the discharge amount of the pulverized grains is high, for obtaining gelatinized starch powder suitable, e.g., for an additive to a food field and a biodegradable resin, capable of controlling the crystallization degrees in a wide range from a region high in the crystallization degree to a region low in the crystallization degree.SOLUTION: Provided is a method for producing gelatinized starch powder where raw material grains are charged to a heating shear pulverization machine, so as to be pulverized, and the grains after the pulverization are discharged from the heating shear pulverization machine at a discharge amount of 1 kg/hr or more: the following formula:Q value=[the residual time (sec) of the raw material grains in the heating shear pulverization machine]×[the maximum shear speed (1/sec)] is 500 or more.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for producing pregelatinized starch powder, and more particularly to improvement of technology in mass production.

  It is generally known that by pregelatinizing (amorphizing) starch contained in cereal grains, different characteristics are developed compared to those before pregelatinization. For example, it is known that pre-pregelatinized rice flour can be stored for a long period of time, but can be eaten deliciously by simply adding water or hot water without requiring steaming. In addition, when starch is used as an additive to biodegradable resins such as PLA (polylactic acid resin), starch is pregelatinized by simultaneously adding a plasticizer such as water or glycerin and processing at a high temperature. It is known that it can be combined with PLA or the like.

  Conventionally pregelatinized starch is usually produced by removing water after suspending raw grain in water and gelatinizing it by heating (ie, cooking rice). However, in the method of dewatering after cooking rice, it was possible to produce starch starch that had been alphalyzed to the level of food simply by adding water or hot water. No starch starch production was possible. The reason is that part of the starch once almost completely pregelatinized by cooking rice is recrystallized by “aging” that occurs in the process of drying (water removal).

  Moreover, when utilizing pregelatinized rice flour, a technology has been proposed in which a thickener is blended as various additives to produce a product (Patent Document 1).

The present inventors put raw grains into a mortar grinder, and pulverized the raw grains under shearing conditions while heating them at a temperature of 80 ° C. or higher, particularly 100 to 200 ° C. A technology for easily producing a modified starch powder without adding water has been developed (Patent Documents 2 and 3). According to the technique described in Patent Document 2, it is possible to perform alpha conversion to the same level as the method of removing water and converting it to alpha after cooking. Furthermore, according to the technique described in Patent Document 3, a standard that is not pregelatinized in differential scanning calorimetry of pregelatinized starch due to conditions such as a gap between two members that move relatively, heating temperature, and moisture content of raw grain. Endothermic enthalpy at the same melting temperature where the numerical value α shown by α = (1−ΔH _T / ΔH _max ) × 100 is 80 or more when the endothermic enthalpy accompanying melting of the sample is ΔH _max Δ It is possible to obtain starch powders that have a high _T and are pregelatinized to a very high degree. This starch powder can have extremely high utility not only for use in the food field but also as an additive to a completely different field, for example, a biodegradable resin such as PLA.

Japanese Patent No. 4190180 Japanese Patent No. 4767128 Japanese Patent No. 5,503,885

  In Patent Documents 2 and 3, the focus is on a technique for achieving alpha conversion, but mass production is a new issue in this technique. Under the conditions for mass production, there has been no knowledge that the degree of crystallinity can be controlled to obtain pregelatinized starch powder suitable for the food field and additives for biodegradable resins.

  For example, although the technique which mix | blends a thickener like patent document 1 is also known, rice flour bread adjusts a viscosity by blending pregelatinized rice flour and crystalline rice flour, and bread-making 100% rice flour bread It becomes possible. However, the technology that can control the physical properties of dough such as bread can be controlled just by controlling the crystallinity of rice and pulverizing it, and can produce food such as rice flour bread without blending as described above. Absent. By controlling crystallinity, there is a need for technology that enables breadmaking without blending crystallized and non-crystallized cereal flour as in the prior art, and pregelatinized starch that can freely control the degree of pregelatinization. The mass production of powder is desired. Furthermore, when grains are conventionally used as livestock feed, it is possible to develop livestock feed that can control the growth rate of livestock for the purpose of adjusting the shipment time of livestock if the grain can be pre-gelatinized. To do. For this purpose, a technique for freely controlling the degree of alpha of the grain (the degree of alpha) is required, but it is difficult to control the degree of alpha by a conventional general method.

  In addition, as described above, under the assumption that industrial mass production is performed by the techniques of Patent Documents 2 and 3, clear knowledge related to pregelatinization is also obtained in pregelatinized starch powder having a high degree of crystallinity. There were no guidelines. For example, under the conditions for mass-producing pregelatinized starch powder such that the grain after pulverization is discharged from a heated shear pulverizer at a discharge rate of 1 kg / hour or more, and further 10 kg / hour or more, the high degree as obtained in Patent Document 2 can be obtained. The specific conditions for obtaining pregelatinized starch powder and the causal relationship between the conditions and mass production were not clear.

  The present invention has been made in view of the circumstances as described above. When producing pregelatinized starch powder by putting raw material grains into a heated shear pulverizer to produce pregelatinized starch powder, mass production conditions in which the discharged amount of pulverized grains is large. In order to obtain pregelatinized starch powder suitable for foodstuffs and additives to biodegradable resin, etc., it is possible to control the crystallinity over a wide range from high to low crystallinity. It is an object to provide a method for producing starch powder.

In order to solve the above-mentioned problems, the pregelatinized starch powder production method of the present invention is a method in which raw material grains are put into a heated shear pulverizer and pulverized. It is a manufacturing method of pregelatinized starch powder discharged above, which has the following formula:
Q value = [Retention time of raw material grains in heated shear pulverizer (sec)] × [Maximum shear rate (1 / sec)]
The raw material grain is pulverized under the condition that the Q value represented by

  According to the present invention, when producing pregelatinized starch powder by putting raw grain into a heat shear mill and adding it to the food field or biodegradable resin in mass production conditions where the discharged amount of ground grain is large. In order to obtain pregelatinized starch powder suitable for an agent or the like, the crystallinity can be controlled over a wide range from a high crystallinity region to a low crystallinity region.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic (top is a top view, the bottom is a side view) which shows an example of the apparatus structure for enforcing the method of this invention. It is principal part sectional drawing of the apparatus of FIG. It is a wide-angle X-ray diffraction graph of the rice flour obtained by milling in Reference Example 1 and unmilled rice grains. 4 is a wide-angle X-ray diffraction graph of rice flour obtained by pulverization at a discharge rate of 1 kg / hour or less in Reference Example 2. It is a graph which shows the relationship between Q value and crystallinity.

  The present invention is described in detail below.

  The present invention is a method for producing pregelatinized starch powder in which raw material grains are put into a heat shear pulverizer and pulverized, and the pulverized grains are discharged from the heat shear pulverizer at a discharge rate of 1 kg / hour or more. The amount of cereal discharged from the heat shear pulverizer is 1 kg / hour or more, 3 kg / hour or more, 5 kg / hour or more, or 10 kg / hour or more.

  As a result of repeated experiments and researches in view of the above problems, the inventors of the present invention have the smallest gap between two members (such as a mortar grinder and a twin-screw kneader) that move relative to the grinder. The Q value is defined as the product of the maximum shear rate and the residence time (corresponding to the discharge rate) as the Q value. Surprisingly, the relative relationship between the crystallinity (corresponding to the pregelatinization degree) is shown in the figure. As a result, the present invention was completed.

  The fact that the crystallinity can be controlled by the Q value is very important in reducing the slight crystallinity at the Q value in terms of using pregelatinized rice flour and crystalline rice flour in various applications. For example, it is known that rice flour bread can be made into 100% rice flour bread by blending pregelatinized rice flour and crystalline rice flour. However, according to the present invention, since the crystallinity of rice can be controlled by the Q value, the physical properties of the dough such as bread can be controlled only by pulverization, and production can be performed without blending as described above. Gluten-free foods that have been difficult can be easily produced.

  As a result of using a medium die from a small die, it was found that Q value = maximum shear rate × dwell time (discharge amount) is an important factor that unambiguously affects the crystallinity. In order to reduce the crystallinity, it is essential to increase the Q value. When the production amount (discharge amount) is increased, the residence time is shortened. Therefore, in order to increase the production amount while maintaining the crystallinity at a certain value or less, it is necessary to increase the maximum shear rate.

  Since the shear rate can be calculated by the peripheral speed / gap, it is important to increase the peripheral speed or decrease the gap by increasing the size of the die.

  This relationship is not limited to the mortar-type pulverization shape, and it can be easily analogized that it can be applied to other pulverization manufacturing methods such as a biaxial kneading pulverizer. That is, as the heat shear pulverizer, any other apparatus other than the mortar pulverizer as shown in FIGS. 1 and 2 may be used as long as the method of the present invention can be carried out. In the present invention, “pulverizing under a shearing condition” does not mean simply compressing and pulverizing, but means pulverizing with an action of shifting both side portions along a surface inside an object. . For example, as a device for pulverizing raw material grains by applying a shearing force, in addition to a mortar grinder, a device for shearing and pulverizing raw material grains while passing the raw material grains through a minute gap between two relatively rotating rollers. Configuration, small-diameter cylindrical or columnar member and large-diameter cylindrical member are placed concentrically and rotated relative to each other, and the raw grain passes through a small gap between the outside of the small-diameter member and the inside of the large-diameter member. It is possible to adopt an apparatus configuration that shears and grinds during the process.

  In the method of the present invention, the raw material grain is pulverized under the condition that the Q value is 500 or more. If the Q value is 500 or more, pregelatinized starch powder in which the crystallization degree of the grain after pulverization by a heat shear pulverizer is lowered to about 15, for example, can be obtained. Gluten-free foods can be processed and commercialized without mixing sugars. In addition, starch powder that has been alpha-blended to the extent that it can be made into food only by adding water or hot water, as described in Patent Document 2, can also be obtained starch starch that has been pregelatinized to a very high degree, It is possible to obtain pregelatinized starch powder in which the degree of pregelatinization is controlled in various ways within a low crystallinity range.

  Considering the point of obtaining pregelatinized starch powder with low crystallinity, it is preferable to pulverize the raw material grain under the condition that the Q value is 3500 or more, and to pulverize the raw material grain under the condition that the Q value is 9000 or more. Particularly preferred. Under such conditions, a pregelatinized starch powder having a lower crystallinity can be obtained, and a pregelatinized starch powder having a crystallinity of cereal after pulverization by a heat shear pulverizer of, for example, less than 6% is obtained. You can also.

  Under the condition that the amount of grain discharged from the heat shearing machine is 1 kg / hour or more, the raw material grain is preferably pulverized under the condition that the Q value is 300,000 or less, and the raw material grain is pulverized under the condition of 100,000 or less. Is more preferable. If the shear rate is increased under such a large amount of discharged grain, clogging is likely to occur.

  When producing pregelatinized starch powder using a mortar grinder as a heating shear pulverizer, the gap between the upper and lower mortars is adjusted appropriately. The gap is not particularly limited in consideration of the grain used as a raw material or the size of the desired flour to be obtained after processing, but it is, for example, in the range of about 0.5 to 0.01 mm, particularly about 0.1 to 0.01 mm. Is arbitrarily adjusted within. Next, after setting the die to a predetermined temperature, the die is rotated at a predetermined rotation speed (corresponding to the shear rate of the grain). Then, the raw material grains are put into a mortar grinder, and the raw material grains are pulverized under a shearing condition at a predetermined temperature. Considering the fact that pregelatinized starch powder can be obtained with various degrees of pregelatinization controlled within a low crystallinity range, that is, fine crystallinity control can be controlled by Q value, etc. Although it does not specifically limit, For example, it is normal temperature or more, or grind | pulverizes on shear conditions, heating at 40 degreeC or more, Preferably it is 80 degreeC or more. The upper temperature limit during pulverization is not particularly limited, but is preferably 200 ° C. or lower. The moisture content of the raw material grain is not particularly limited, but is preferably 10% or more.

  In the present invention, pregelatinized starch powder is intended for all grains containing starch as a main component, for example, rice, wheat, soybean, red beans, buckwheat, potatoes, beans, corn, etc. These can be pregelatinized and milled in a short time.

  The highly pregelatinized starch powder is expected to be used not only in the conventional food field but also in various fields. For example, since it exhibits good dispersibility and compatibility with plastics such as PLA, it is possible not only to eliminate the need to use a plasticizer such as water or glycerin, but also to improve the mechanical properties. Therefore, it is also useful as a plastic additive. Furthermore, it is an effective method as a pre-treatment technology during bioethanol production, and it can impart high enzyme reactivity without the gelatinization (pregelatinization) process of raw starch as in the past, and gelatinization in bioethanol production. Since the (alpha) process can be saved, the production process can be simplified.

  Furthermore, according to the present invention, it is possible to produce pregelatinized starch powders having various degrees of pregelatinization by arbitrarily selecting the pulverization conditions, and therefore it is possible to produce cereals having different swelling properties with respect to cold water. That is, it is possible to arbitrarily produce grain flour having various dough viscosities. This can also be obtained by the present invention, for example, rice flour 100% bread, which has been considered to be impossible to make bread because the dough is poorly sticky, and “binder” in 100% buckwheat. It becomes possible to apply pregelatinized starch powder as a viscosity modifier.

  Furthermore, according to the present invention, since starch can be pregelatinized easily and instantaneously, it is possible to eliminate the necessity for all processing treatments in which the previous step of boiling was required, and it has a very wide range of applications. . For example, for use as an industrial material, saccharification of starch when synthesizing lactic acid, which is a raw material of biodegradable resin, plastic / starch composite material, pregelatinization obtained by the method of the present invention in bioethanol production process, etc. If starch powder is used, this pre-process becomes unnecessary, and the alpha conversion process such as rice cooking required by the prior art can be omitted. Therefore, there is a great merit in terms of cost and process. In addition, in the case of fermentation in the brewing process, koji fermentation at the time of miso production, etc., the previous process of simmering cereals that are mainly starch, such as corn, rice, and flour (cooking rice) has always been required. However, if the pregelatinized starch obtained by the present invention is used, the previous step is unnecessary, and there is a great advantage in terms of cost and process.

  Thus, the pregelatinized starch powder obtained by the method of the present invention can be widely applied not only as a food product but also as an industrial material, and the present invention is remarkably high in a wide range of industrial fields. Has availability.

  FIG. 1 is a schematic diagram showing an example of a device configuration for carrying out the method of the present invention. The apparatus 10 includes an upper mill 11 that is fixedly installed, and a lower mill 12 that is rotatably provided between the upper mill 11 via a predetermined gap 13. The upper mill 11 is formed in a ring shape with a raw material inlet 14 for feeding raw material grains such as rice grains at the center. The insertion port 14 communicates with the gap 13 on the bottom surface of the upper mill 11. The lower mill 12 is formed in a disk shape having substantially the same outer diameter as the upper mill 11.

  The lower mill 12 is rotationally driven by a motor 15 at a predetermined speed. The gap 13 between the upper mill 11 and the lower mill 12 can be adjusted within the range of the gap adjusting section 16, and particularly depending on the grain used as a raw material, the size of desired flour to be obtained after processing, etc. Although not limited, it is arbitrarily adjusted within a range of, for example, about 0.5 to 0.01 mm, particularly about 0.1 to 0.01 mm.

  The upper die 11 is provided with a heater 17. The heater 17 is formed in a ring shape having substantially the same outer diameter as the upper mill 11 and an opening having substantially the same diameter as the raw material inlet 14. The heater 17 is connected to a temperature controller 19 through a heater cord 18 and heats the upper die 11 by heating to a temperature set by the temperature controller 19. The computer 22 compares the set temperature by the temperature controller 19 (input from the data cable 23) with the measured temperature by the thermocouple (not shown) (input from the data cable 21), and the heater via the temperature control cable 24. A control signal is supplied to the temperature controller 19.

  Further, the computer 22 gives a motor control signal to the motor 15 via the motor control cable 25 to control the number of rotations of the lower mill 12 by the motor 15. The rotational speed of the lower mill 11 is set so that the shear rate that the grain thrown into the gap 13 receives between the fixed upper mill 11 and the rotating lower mill 12 becomes a target value.

  A tray 26 having an inner diameter sufficiently larger than these outer diameters is provided below the upper mill 11 / lower mill 12. A flour dropping port 27 is opened on the bottom surface of the saucer 26. The flour (rice flour etc.) processed by the apparatus 10 is dropped from the saucer 26 and further passed through a flour dropping chute 28 to a predetermined container (not shown). And so on.

  As shown in FIG. 2, which is a cross-sectional view of the main part of the apparatus 10, the upper mill 11 has a raw material passage 11c from the inner surface 11a to the bottom surface 11b facing the raw material inlet 14, which is tapered in cross section and spiral in plan view. It is formed in a shape. Since the accommodating portion 20 enlarged by the tapered passage 11c is formed at the lower end portion of the raw material inlet 14, the raw material grain introduced into the raw material inlet 14 immediately enters the gap 13 and is sheared and crushed. It is heated by heat transfer or heat radiation from the inner surface 11a of the upper mill 11 heated by the heater 17 and entering the housing portion 20. The above-described thermocouple is inserted into a hole formed from the side surface of the upper die 11 toward the center, and approximately shows the processing temperature when being sheared and ground in the gap 13 between the upper die 11 and the lower die 12. ing. On the surface facing the gaps 13 of the upper mill 11 and the lower mill 12, a plurality of concave grooves extending in the direction intersecting with the circumferential direction are formed in order to increase the shearing force on the raw grain.

  Next, the pregelatinized milling process performed using the apparatus 10 will be described. First, the gap 13 between the upper die 11 and the lower die 12 is adjusted via the gap adjusting unit 16 according to the size of the raw material grain, the processed flour, and the like. In addition, the temperature controller 19 heats the heater 17 to a predetermined temperature (for example, within a range of 80 to 140 ° C. and can be set in increments of 10 ° C.), and the upper die 11 is heated by the heat conduction. Further, the motor 15 is driven at the rotation speed controlled by the computer 22 to rotate the lower mill 12 so as to give the predetermined shear rate.

  Since the preparation of the apparatus 10 is completed as described above, the raw material grains are input into the input port 14 and the processing is started. Since the heater 17 has already been heated to a predetermined temperature and thereby the upper mill 11 is also heated, the grain passes through the heater 17 and the insertion port 14 and further passes through the tapered passage 11c or the accommodating portion 29. Is heated to a temperature corresponding to the heater temperature, and immediately thereafter, it is fed into the gap 13 between the lower die 12 and crushed by receiving a shearing force between the fixed upper die 11 and the rotating lower die 12. Is done. Flour (rice flour) obtained by shearing and grinding is discharged from the side of the gap 13 and accommodated in a receiving tray 26, and is collected in a predetermined container (not shown) through a drop port 27 and a drop chute 28.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

In the following examples, the shear rate, residence time, Q value, and crystallinity of pulverized rice flour were measured by the following methods.
(1) Maximum Shear Speed The peripheral speed was determined from the rotation speed of the motor 15 and the circumference of the upper and lower dies 11 and 12, and the maximum shear speed pulverized from the following relationship was defined from the value of the gap 13.
Peripheral speed [mm / s] = (number of revolutions [rpm] × circumference [mm]) / 60
Maximum shear rate [1 / sec] = peripheral speed [mm / s] / gap [mm])
(2) Residence time The residence time was defined from the following relationship based on the value of the discharge amount during pulverization.
Residence time [sec] = 1 / Discharge rate (3) Q value The Q value was determined from the following equation.
Q value = [Retention time of raw material grains in heated shear pulverizer (sec)] × [Maximum shear rate (1 / sec)]
(4) Crystallinity The peak was separated into crystal reflection and amorphous scattering from the measurement result of wide angle X-ray diffraction. The integral value of the peak due to the resulting amorphous scattering S _a, the integral value of the peak due to the crystal reflecting the S _c. The crystallinity of the pulverized rice flour was determined from the following relationship.
Crystallinity (%) = (S _c / (S _c + S _a )) × 100
The experimental specifications of the wide-angle X-ray diffraction are as follows.
・ Measurement equipment RINT-RAPID manufactured by Rigaku
・ Measurement conditions Scan speed 4 ° / min
Measurement angle 5-35 °
Tube voltage 40 kV
Tube current 30mA
<Reference Example 1>
Raw rice was coarsely ground in a mortar and subjected to wide angle X-ray diffraction.
<Reference Example 2>
Milling was actually performed using the apparatus 10 having the structure shown in FIGS. 1 and 2 using rice grains having a moisture content of 14.4%, which is standard as general stored rice, as raw materials. In the apparatus 10 used, the upper mortar 11, the lower mortar 12 and the heater 17 all have an outer diameter of 90 mm (radius 45 mm) and have an inlet 14 having a diameter of 10 mm at the center thereof. The tapered raw material passage 11c of the upper mill 11 is formed over a range of 5 mm from the inner surface 11a (FIG. 2). The milling gap 13 was fixed to 0.01 mm (10 μm), the rotational speed of the motor 15 was 240 rpm, and the amount of rice grains charged was 120 g / h. The milling process was performed at a pulverization temperature of 120 ° C.
<Reference Example 3>
The apparatus 10 having the same configuration as that of Reference Example 2 was used, but in this example, the outer dimension of the lower mill 12 was changed to 60 mm (radius 30 mm), and the gap 13 between the mills was fixed to 0.01 mm (10 μm). The rotational speed of 15 was 100 rpm, and the actual milling process was performed at a rice grain input of 120 g / h. The milling process was performed at a pulverization temperature of 120 ° C.
<Reference Example 4>
Using the apparatus 10 having the same configuration as that of Reference Example 2, the gap 13 between the mortars is fixed to 0.01 mm (10 μm), the rotation speed of the motor 15 is 240 rpm, and the input amount of rice grains is 200 g / h. Milling was performed. The milling process was performed at a pulverization temperature of 120 ° C.
<Reference Example 5>
The apparatus 10 having the same configuration as that of Reference Example 2 was used, but in this example, the outer dimension of the lower mill 12 was changed to 60 mm (radius 30 mm), and the gap 13 between the mills was fixed to 0.01 mm (10 μm). The rotational speed of 15 was 240 rpm, and the actual milling process was performed at a rice grain input rate of 200 g / h. The milling process was performed at a pulverization temperature of 120 ° C.

<Example 1>
Although the apparatus 10 having the same configuration as that of the reference example 2 was used, in this embodiment, the upper die 11, the lower die 12 and the heater 17 are all formed with an outer diameter of 250 mm (radius of 125 mm). The actual milling process was performed with the gap 13 between the mortars fixed to 0.01 mm (10 μm), the rotational speed of the motor 15 being 50 rpm, and the input amount of rice grains being 6.5 kg / h. The milling process was performed at a pulverization temperature of 120 ° C.
<Example 2>
Using the apparatus having the same configuration as in Example 1, the gap 13 between the mortars is fixed to 0.01 mm (10 μm), the rotation speed of the motor 15 is 100 rpm, and the input amount of rice grains is 6.5 kg / h. The actual milling process was performed. The milling process was performed at a pulverization temperature of 120 ° C.
<Example 3>
Using the apparatus having the same configuration as in Example 1, the gap 13 between the mortars was fixed to 0.01 mm (10 μm), the rotation speed of the motor 15 was 50 rpm, and the input amount of rice grains was 11.5 kg / h. The actual milling process was performed. The milling process was performed at a pulverization temperature of 120 ° C.
<Example 4>
Using the apparatus having the same configuration as in Example 1, the gap 13 between the mortars was fixed to 0.01 mm (10 μm), the rotation speed of the motor 15 was 100 rpm, and the input amount of rice grains was 11.5 kg / h. The actual milling process was performed. The milling process was performed at a pulverization temperature of 120 ° C.
<Example 5>
Using the apparatus having the same configuration as in Example 1, the gap 13 between the mortars is fixed to 0.04 mm (40 μm), the rotation speed of the motor 15 is 45 rpm, and the input amount of rice grains is 6.5 kg / h. The actual milling process was performed. The milling process was performed at a pulverization temperature of 120 ° C.
<Example 6>
Using the apparatus having the same configuration as that of Example 1, the gap 13 between the mortars was fixed to 0.07 mm (70 μm), the rotational speed of the motor 15 was set to 45 rpm, and the input amount of rice grains was 4 kg / h. Milling was performed. The milling process was performed at a pulverization temperature of 120 ° C.
<Example 7>
Using the apparatus having the same configuration as in Example 1, the gap 13 between the mortars was fixed to 0.1 mm (100 μm), the rotation speed of the motor 15 was 45 rpm, and the input amount of rice grains was 6.5 kg / h. The actual milling process was performed. The milling process was performed at a pulverization temperature of 120 ° C.
<Example 8>
Using the apparatus having the same configuration as in Example 1, the gap 13 between the mortars was fixed to 0.3 mm (300 μm), the rotation speed of the motor 15 was 45 rpm, and the input amount of rice grains was 6.5 kg / h. The actual milling process was performed. The milling process was performed at a pulverization temperature of 120 ° C.
<Example 9>
Using the apparatus having the same configuration as in Example 1, the gap 13 between the mortars was fixed to 0.5 mm (500 μm), the number of revolutions of the motor 15 was 45 rpm, and the input amount of rice grains was 6.5 kg / h. The actual milling process was performed. The milling process was performed at a pulverization temperature of 120 ° C.
<Example 10>
Using the apparatus having the same configuration as in Example 1, the gap 13 between the mortars was fixed to 0.7 mm (700 μm), the rotation speed of the motor 15 was 45 rpm, and the input amount of rice grains was 6.5 kg / h. The actual milling process was performed. The milling process was performed at a pulverization temperature of 120 ° C.

<Comparative Example 1>
Using the apparatus having the same configuration as in Example 5, the gap 13 between the mortars was fixed to 1 mm (1000 · incense j, the motor 15 was rotated at 45 rpm, the amount of rice grains charged was 6.5 kg / h, The actual milling process was performed, and the milling process was performed at a pulverization temperature of 120.
<Comparative example 2>
Table 4 shows the crystallinity of zero Q, that is, unmilled rice grains.

  As described above, the amount of crystallization, the crystallinity at each Q value, was measured by changing the input amount, die diameter, rotation speed, shear rate, discharge amount, residence time, and the like. The results are shown in Tables 1 to 4. These results are shown in FIG. 5 as a graph of Q value and crystallinity.

  From Tables 1 to 4, when the pulverized rice flour is discharged from the mortar grinder at a discharge rate of 1 kg / hour or more, the product of the maximum shear rate and the residence time is defined as the Q value. It has been found that the relative relationship is clearly as shown in FIG. That is, it is found that the Q value is an important factor that unambiguously affects the crystallinity, and in order to reduce the crystallinity, it is essential to increase the Q value, and the production amount (discharge amount). It has been clarified that increasing the maximum shear rate is necessary in order to increase the production amount while maintaining the crystallinity at a certain value or less because the residence time is shortened when the is increased.

DESCRIPTION OF SYMBOLS 10 Heat shear mill 11 Upper die 11a Inner surface 11b Bottom surface 11c Tapered raw material path 12 Lower die 13 Gap 14 Raw material inlet 15 Motor 16 Gap adjustment part 17 Heater 18 Heater cord 19 Temperature controller 20 Storage part 21 Data cable 22 Computer 23 Data Cable 24 temperature control cable 25 motor control cable 26 saucer 27 flour outlet 28 flour dropping chute

Claims (7)

A method for producing pregelatinized starch powder, in which raw material grains are put into a heat shear pulverizer and pulverized, and the pulverized grains are discharged from the heat shear pulverizer at a discharge rate of 1 kg / hour or more.
Q value = [Retention time of raw material grains in heated shear pulverizer (sec)] × [Maximum shear rate (1 / sec)]
The pregelatinized starch powder is produced by crushing raw material grains under a condition where the Q value represented by   The method for producing pregelatinized starch powder according to claim 1, wherein the heat shear pulverizer is a mortar pulverizer.   The method for producing pregelatinized starch powder according to claim 1 or 2, wherein the raw material grain is pulverized under a condition where the Q value is 9000 or more.   The method for producing pregelatinized starch powder according to any one of claims 1 to 3, wherein the amount of grain discharged from the heat shearing mill is 10 kg / hour or more.   The method for producing pregelatinized starch powder according to any one of claims 1 to 4, wherein the raw grain is heated to a temperature of 80 ° C or higher and pulverized.   The method for producing pregelatinized starch powder according to any one of claims 1 to 5, wherein the moisture content of the raw material grain is 10% or more.   The method for producing pregelatinized starch powder according to any one of claims 1 to 6, wherein the crystallinity of the grain after pulverization by a heat shear pulverizer is less than 6%.