JP2010215861A - Pregelatinized starch flour and method for producing the same, and plastic additive and composite material using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pregelatinized starch flour simply and within a short time, regardless of material grain and without adding water. <P>SOLUTION: The pregelatinized starch flour has endothermic enthalpy ΔH<SB>T</SB>satisfying the following formula: α=(1-ΔH<SB>T</SB>/ΔH<SB>max</SB>)×100 (wherein α is ≥80, and ΔH<SB>max</SB>is endothermic enthalpy following melting of non-pregelatinized standard sample, and ΔH<SB>T</SB>is endothermic enthalpy at the same melting temperature), and is produced by charging and grinding material grain having moisture content of ≥12% in a gap 13 between mortars set to ≤0.01 mm, and applying shear force at 80°C or higher temperature. Since the pregelatinized starch flour has extremely high dispersibility and compatibility when added to plastics such as polylactic acid, it is useful as a plastic additive, improving mechanical properties of the resulting plastic/starch flour composite material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to pregelatinized starch powder obtained by pulverizing raw material grains under shearing conditions, a method for producing the same, and a plastic additive and a composite material using the pregelatinized starch powder.

  It is generally known that by pregelatinizing (amorphizing) starch contained in cereal grains, different properties are developed compared to those before pregelatinization. In other words, it is known that pre-gelatinized rice flour can be stored for a long period of time, but can be eaten deliciously by simply adding water or hot water without the need for 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). Patent Document 1 describes a technique for producing a pregelatinized starch powder by pulverizing raw material grains under shearing conditions while heating them to a temperature of 80 ° C or higher, particularly 100 to 200 ° C.

Japanese Patent Laid-Open No. 2007-075104

  However, in the method of dewatering after cooking rice, it was possible to produce starch powder that was alpha to the extent that it can be made into food simply by adding water or hot water, but those starch powders are almost completely It was not possible to produce starch powder that had been pregelatinized. 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, it is difficult to perform complete alpha conversion by the method described in Patent Document 1, and it was only possible to perform alpha conversion to substantially the same level as the method of dewatering after rice cooking and performing alpha conversion.

  These prior arts were premised on food use, so there was no dissatisfaction with the degree of pregelatinization, and a higher degree or almost completely pregelatinized starch flour was produced. There was no such request. However, starch powders that are very highly or almost completely pregelatinized are significantly different in starch structure from previously known starch powders that are only pregelatinized to a low level, improving the reactivity of starch molecules. By doing so, it is expected to show more remarkable characteristics.

  As a result of many experiments and researches from such a background, the inventors succeeded in obtaining starch powder that has been pregelatinized to a very high degree, and this starch powder has been recognized in the past. It has been found that it can be extremely useful not only in food applications but also in completely different fields. One of them is useful as an additive to biodegradable resins such as PLA (polylactic acid resin). As described above, starch has been conventionally added to PLA, but it has been necessary to disperse starch in plastic using a plasticizer such as water or glycerin. This is considered to be because starch powder obtained by a conventional production method is not necessarily pregelatinized to a sufficient extent, and this inhibits dispersibility in plastics.

  In addition, it is known that a polyester-based material such as PLA is hydrolyzed to have a low molecular weight when water is present at the time of melting, causing a decrease in physical properties. Therefore, if water is used when adding starch to such plastics, there is a concern that the physical properties will be reduced.

  Therefore, an object of the present invention is to provide a starch powder that maintains a pregelatinized state to a high level that does not exist in the past, and is also useful for new and useful applications as described above. It is to provide a manufacturing method. It is also an object of the present invention to provide a novel technique for freely controlling the degree of alpha conversion.

  In view of the above problems, the present inventors conducted experiments to find the conditions necessary for increasing the degree of pregelatinization to nearly 100% in the method of shearing and pulverizing raw material grains without adding water. As a result of repeated research, it is particularly important to increase the physical force (shearing force) applied to the raw material grain by setting the gap between two relatively moving members (such as a die) to be smaller than a predetermined threshold value. In addition, it is important to understand that the temperature at the time of grinding and the amount of moisture that the raw material grains have absorbed from the beginning have a great influence on the degree of pregelatinization that is finally obtained. It came.

That is, in the present invention, a numerical value represented by α = (1−ΔH _T / ΔH _max ) × 100, where ΔH _max is an endothermic enthalpy accompanying melting of a standard sample that is not pre-alphabated in differential scanning calorimetry. An pregelatinized starch powder having an endothermic enthalpy ΔH _T at the same melting temperature such that α is 80 or more, preferably 85 or more, more preferably 90 or more.

  The BAP method is known as a method for measuring the degree of pregelatinization (degree of pregelatinization), but this method quantifies the degree of activation (non-crystallinity) associated with the non-crystallization of starch. Difficult to do. Because the BAP method uses an enzyme reaction, the numerical value tends to vary depending on the skill level of the measurer. The BAP method can be used even when the starch is not amorphous, such as when the starch granules are damaged. In some cases, a high numerical value is measured, and the numerical value indicating the degree of alpha conversion is not reliable. In the present invention, a numerical value indicating the degree of pregelatinization is calculated on the basis of the measurement of the differential heat associated with the amorphousization of starch and in comparison with a standard sample that is not substantially pregelatinized. The non-crystallinity can be accurately and quantitatively indicated, and the calculated value α is used as an extremely reliable index.

  The present invention also relates to a method for efficiently producing such pregelatinized starch powder with α ≧ 80 in a short time under non-hydrolysis conditions, and according to one embodiment, the two members move relatively. It is a method for producing pregelatinized starch powder, characterized in that the raw grain is put into the gap with a gap of less than 0.02 mm and pulverized by applying a shearing force, according to another embodiment, A pregelatinized starch powder, characterized in that the gap between the two moving members is set to 0.01 mm or less, and the raw material grain is put into the gap to give a shearing force and pulverized. According to the embodiment, the gap between two relatively moving members is set to less than 0.02 mm, and the raw material grain is put into the gap and is pulverized by applying a shearing force at a temperature of 80 ° C. or higher. alpha A method for producing starch powder, and according to another embodiment, the gap between two relatively moving members is less than 0.04 mm, and raw material grains having a moisture content of 15% or more are introduced into the gap. It is a manufacturing method of pregelatinized starch powder characterized by giving shearing force at the temperature of more than ° C, and according to other embodiment, the gap between two relatively moving members is 0.01 mm. A method for producing pregelatinized starch powder, characterized in that raw grain having a moisture content of 12% or more is introduced into the gap and pulverized by applying a shearing force at a temperature of 80 ° C. or higher.

The present invention also proposes a novel method for arbitrarily controlling the numerical value α represented by the above formula, that is, the degree of pregelatinization of starch powder obtained by shearing and grinding the raw material grains. In the method of producing pregelatinized starch powder by putting into a gap between two relatively moving members and applying a shearing force to grind, the size of the gap, the temperature during shear grinding and the moisture content of the raw grain By setting the three conditions in combination, the endothermic enthalpy accompanying melting of the standard sample that has not been pregelatinized in differential scanning calorimetry is ΔH _max , and the endothermic enthalpy ΔH _T at the same melting temperature of the pregelatinized starch produced α when _{= (1- △ H T / △} H max) alpha and controls the numerical α indicated by × 100 Cadet It is a manufacturing method of Pung powder.

  The present invention also proposes a novel use of pregelatinized starch powder in which the numerical value α represented by the above formula is α ≧ 80, and according to one embodiment, the pregelatinized starch powder is a main component. According to another embodiment, the plastic additive is a composite material obtained by adding the pregelatinized starch powder to a biodegradable resin, and according to another embodiment, the pregelatinized starch powder is A composite material added to lactic acid resin.

  According to the present invention, starch powder is provided that has been pregelatinized to a high degree that has not existed previously. The starch powder that has been pregelatinized to such a high degree has utility as an additive to biodegradable resins such as PLA (polylactic acid resin) as well as to the conventionally known use in the food field. New applications are expected in a wide range of fields.

  Further, according to the present invention, in the method of shearing and pulverizing raw material grains such as rice flour, by controlling the production conditions, starch powder that has been pregelatinized to a very high level can be obtained, In addition, the degree of alpha conversion can be controlled in various ways.

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 implementing this invention method. It is principal part sectional drawing of this apparatus. 2 is a wide-angle X-ray diffraction graph of rice flour obtained by milling with a gap changed in Example 1. It is a graph which shows the differential scanning calorimetry result of the same rice flour. 4 is a wide-angle X-ray diffraction graph of rice flour obtained by milling rice grains having a moisture content of 4.44% in Example 2 and changing the temperature conditions with a gap of 0.01 mm. It is a wide angle X-ray diffraction graph of the rice flour obtained by milling rice grains having a moisture content of 10.89% in Example 2 and changing the temperature conditions at a gap of 0.01 mm. It is a wide-angle X-ray diffraction graph of the rice flour obtained by milling rice grains having a moisture content of 12.73% in Example 2 and changing the temperature conditions at a gap of 0.01 mm. It is a wide-angle X-ray diffraction graph of the rice flour obtained by milling rice grains having a moisture content of 17.57% in Example 2 and changing the temperature conditions at a gap of 0.01 mm. It is a differential scanning calorimetry graph of the rice flour obtained by milling rice grains having a moisture content of 4.44% in Example 2 and changing the temperature conditions at a gap of 0.01 mm. It is a differential scanning calorimetry graph of the rice flour obtained by milling rice grains having a moisture content of 10.89% in Example 2 and changing the temperature conditions with a gap of 0.01 mm. It is a differential scanning calorimetry graph of the rice flour obtained by milling rice grains having a moisture content of 12.73% in Example 2 and changing the temperature condition at a gap of 0.01 mm. It is a differential scanning calorimetry graph of the rice flour obtained by milling rice grains having a moisture content of 17.57% in Example 2 and changing the temperature conditions at a gap of 0.01 mm. In Example 2, it is a graph which calculates and shows the numerical value which shows the degree of pregelatinization about the rice flour obtained by using rice grains with a moisture content of 4.44% as a raw material and changing the temperature conditions at a gap of 0.01 mm. is there. In Example 2, it is a graph which calculates and shows the numerical value which shows the degree of pregelatinization about the rice flour obtained by using rice grains with a moisture content of 10.89% as a raw material and changing the temperature conditions at a gap of 0.01 mm. is there. In Example 2, it is a graph which calculates and shows the numerical value which shows the degree of pregelatinization about the rice flour obtained by using rice grains with a moisture content of 12.73% as a raw material and changing the temperature conditions at a gap of 0.01 mm. is there. In Example 2, it is the graph which calculates and shows the numerical value which shows the degree of pregelatinization about the rice flour obtained by making the rice grain of moisture content 17.57% into a raw material, and changing the temperature conditions by gap 0.01mm. is there. It is a wide-angle X-ray diffraction graph of the rice flour obtained by milling rice grains having a moisture content of 4.44% in Example 3 and changing the temperature conditions at a gap of 0.035 mm. It is a wide angle X-ray diffraction graph of the rice flour obtained by milling rice grains having a moisture content of 10.89% in Example 3 and changing the temperature conditions at a gap of 0.035 mm. It is a wide-angle X-ray diffraction graph of the rice flour obtained by milling rice grains having a moisture content of 12.73% in Example 3 and changing the temperature conditions at a gap of 0.035 mm. It is a wide-angle X-ray diffraction graph of the rice flour obtained by milling rice grains having a moisture content of 17.57% in Example 3 and changing the temperature conditions at a gap of 0.035 mm. It is a differential scanning calorimetry graph of the rice flour obtained by milling rice grains having a moisture content of 4.44% in Example 3 and changing the temperature conditions at a gap of 0.035 mm. It is a differential scanning calorimetry graph of the rice flour obtained by milling rice grains having a moisture content of 10.89% in Example 3 and changing the temperature conditions at a gap of 0.035 mm. It is a differential scanning calorimetry graph of the rice flour obtained by milling rice grains having a moisture content of 12.73% in Example 3 and changing the temperature condition at a gap of 0.035 mm. It is a differential scanning calorimetry graph of the rice flour obtained by milling rice grains having a moisture content of 17.57% in Example 3 and changing the temperature conditions at a gap of 0.035 mm. In Example 2, it is the graph which calculates and shows the numerical value which shows the degree of pregelatinization about the rice flour obtained by using rice grains with a moisture content of 4.44% as a raw material and changing the temperature conditions at a gap of 0.035 mm. is there. In Example 2, it is a graph which calculates and shows the numerical value which shows the degree of pregelatinization about the rice flour obtained by using rice grains with a moisture content of 10.89% as a raw material and changing the temperature conditions at a gap of 0.035 mm. is there. In Example 2, it is a graph which calculates and shows the numerical value which shows the degree of pregelatinization about the rice flour obtained by using rice grains with a moisture content of 12.73% as a raw material and changing the temperature conditions at a gap of 0.035 mm. is there. In Example 2, it is the graph which calculates and shows the numerical value which shows the degree of pregelatinization about the rice flour obtained by using the rice grain of moisture content 17.57% as a raw material, and changing the temperature conditions with a gap of 0.035 mm. is there. It is explanatory drawing explaining the method of calculating the numerical value which shows the grade of pregelatinization about a starch powder sample. It is a wide-angle X-ray-diffraction graph of the air-flow ground raw rice flour (beta rice flour) used as a standard sample in calculating the numerical value indicating the degree of pregelatinization. It is a differential scanning calorimetry graph of the same airflow ground raw rice flour (beta rice flour). Mechanical properties (tensile strength) when fully pregelatinized rice flour according to the present invention is added to PLA (polylactic acid resin), when commercially available pregelatinized rice flour is added, when raw rice flour (beta rice flour) is added, and PLA alone It is a graph shown in comparison with the case of. Dispersibility when fully pregelatinized rice flour according to the present invention is added to PLA (polylactic acid resin) is compared with the case where commercially available pregelatinized rice is added, raw rice flour (beta rice flour) is added, and PLA alone. FIG. It is a graph which shows the saccharification characteristic of the fully pregelatinized rice flour by this invention compared with commercial pregelatinized rice and raw rice flour (beta rice flour).

  FIG. 1 is a schematic view 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 is set to 0. 0 depending on the grain used as a raw material, the size of desired flour to be obtained after processing, and the like. It is arbitrarily adjusted within a range of about 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. Rotational speed of the lower die 11, shear rate 90～600Sec ^-1 receive between the lower die 12 grains charged into the gap 13 rotates the upper die 11 of the fixed, preferably a 280～600Sec ^-1 It is preferable to set so as to be.

  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 29 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 11 a of the upper mill 11 heated by the heater 17. 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 mill 11 and the lower mill 12 through the gap adjusting unit 16 is set to 0.5 to 0.01 mm, particularly 0. It is arbitrarily adjusted within a range of about 1 to 0.01 mm. The temperature controller 19 heats the heater 17 to a predetermined temperature (for example, it can be set in steps of 10 ° C. within a range of 80 to 140 ° 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.

  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 50 mm (radius 25 mm), and have an inlet 14 having a diameter of 10 mm at the center. 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 gap 13 between the dies was changed to seven types of 0.01 mm, 0.02 mm, 0.03 mm, 0.07 mm, 0.11 mm, 0.15 mm and 0.51 mm, and the same grinding temperature (measured by the above-mentioned thermocouple). Temperature (also in the following examples) Milling was performed at 120 ° C.

  The results of this milling treatment are shown in FIG. 3 (wide-angle X-ray diffraction graph) and FIG. 4 (differential scanning calorimetry graph). From these graphs, even if the pulverization process is performed at 120 ° C. and a sufficient heating temperature condition, if the gap 13 is 0.03 mm or more, a sharp peak clearly remains in wide-angle X-ray diffraction (FIG. 3). Moreover, since large endothermic enthalpy is recognized also in differential scanning calorimetry (FIG. 4), it turns out that alpha-ization is not enough. When the gap is 0.02 mm, although it is somewhat insufficient, it is recognized that the pregelatinization has progressed to a considerable extent, and when the gap becomes 0.01 mm, the state is almost completely pregelatinized.

  The apparatus 10 having the same configuration as that of Example 1 was used, but in this example, the gap 13 between the mortars was fixed to 0.01 mm (10 μm), and the pulverization temperature was 15 ° C. (room temperature condition in which the heater 17 was not operated). , 80 ° C., 100 ° C. and 120 ° C., and the moisture content of the rice grain as the raw grain is 4.44%, 10.89%, 12.73% and 17.57% (new rice), Actual milling was performed under each union condition.

  The results of this milling treatment are shown in FIGS. 5 to 8 (wide-angle X-ray diffraction graph) and FIGS. 9 to 12 (differential scanning calorimetry graph). From these graphs, it was found that when the inter-gap gap 13 was made as small as 0.01 mm, it could be sufficiently alphatized by pulverization under a temperature condition of 80 ° C. or higher regardless of the moisture content of the raw rice grains.

  By the way, in starch grains contained in cereal grains, starch molecules are regularly arranged by hydrogen bonding between starch molecules to form a kind of crystals. This means a state in which the regularity due to bonding is broken (amorphized), and conventionally, the degree of pregelatinization has been mainly determined by wide-angle X-ray diffraction. That is, as the sharp peak disappears in the wide-angle X-ray diffraction, the alpha conversion progresses, and it can be considered that the alpha conversion is insufficient when the sharp peak remains. In order to judge more clearly, it is useful to use a technique that measures the amount of heat absorbed during gelatinization (pregelatinization) in the presence of starch grains and water by differential scanning calorimetry (hereinafter “DSC measurement”). It is. Even if the peak appears to disappear in wide-angle X-ray diffraction, DSC measurement may cause endotherm, DSC measurement is more sensitive to the structure, and the degree of alpha conversion can be grasped with higher accuracy. can do. However, there have been few attempts to quantify the degree of starch pregelatinization. The present inventors tried to quantify the degree of alpha conversion from the results of DSC measurement. As described above, according to DSC measurement, the endothermic amount when starch is melted can be used as having a correlation with the degree of pregelatinization. In this example, the temperature (horizontal axis) is gradually increased. The amount of heat (vertical axis) when endotherm was generated was measured (FIGS. 9 to 12). Since the melting temperature of rice flour starch is about 62 ° C. (also apparent from FIG. 4), the enthalpy of work related to endotherm at this melting temperature is represented by ΔH (J / g). The smaller the endothermic enthalpy, the smaller the proportion of crystals, that is, the higher the degree of amorphization = alpha, and “No Peak” is completely amorphized = alpha because no endotherm is observed. It means that

By applying this principle, it becomes possible to quantify the degree of pregelatinization of starch powder as an absolute index based on the result of DSC measurement. That is, as shown in FIG. 29, the endothermic enthalpy (ΔH _max ) at the melting temperature is measured in advance using a sample that is substantially not pregelatinized, that is, raw rice (beta rice) as a standard sample, If the endothermic enthalpy (ΔH _T ) at the same melting temperature of the sample to be measured is measured, the degree of pregelatinization of the sample can be calculated from the following equation. As the endothermic enthalpy (ΔH _T ) of the sample to be measured becomes smaller than the endothermic enthalpy (ΔH _max ) of the standard sample, the calculated numerical value (α) becomes higher, indicating that the endothermic enthalpy (ΔH _T ) of the sample to be measured is alpha. In the case of “No Peak”, the endothermic enthalpy is zero, that is, ΔH _T = 0, so α = 100, which indicates that it is completely alphalated.
α = (1−ΔH _T / ΔH _max ) × 100

As a standard sample, “Haenuki” produced in Yamagata Shonai in 2006 was air pulverized with an air tag mill pulverizer MP5-500 manufactured by Micro Powertec Corporation. The results of wide-angle X-ray diffraction and DSC measurement of this raw rice flour are shown in graphs in FIGS. 30 and 31, respectively. As shown in the graph of FIG. 31, the endothermic enthalpy (ΔH _max ) at the melting temperature (about 62 degrees) of this raw rice flour was 7.4 (J / g).

  Based on the DSC measurement results shown in FIGS. 9 to 12, a numerical value α indicating the degree of pregelatinization is calculated from the above formula and shown in FIGS. 13 to 16. From these graphs, it can be seen that when the inter-gap gap 13 is reduced to 0.01 mm, the water content of the raw rice grains can be sufficiently alphatized by pulverization under a temperature condition of 80 ° C. or higher, It was found that the numerical value indicating the degree of pregelatinization is approximately α ≧ 80.

In addition, as already stated, according to the existing manufacturing method in which water is removed after rice cooking and milled, even if it is almost completely amorphized once by rice cooking, it is recrystallized by aging in the subsequent water removal process, and heat absorption in DSC occurs. This has already been clarified in many papers. Some of them are exemplified below. Therefore, it is considered that the numerical value α of the commercially available pre-gelatinized rice flour obtained by this existing production method is reduced to less than 80.
(1) Fumio Nakazawa, Shun Noguchi, Junko Takahashi and Masako Takada; Gelatinization and Retrogradation of Rice Starch Studied by Differential Scanning Calorimetry; Agric. Biol. Chem .; 48 (1), 201-203 (1984)
(2) Takayuki Umemoto, Tetsuya Horibata, Noriaki Aoki, Mayu Hiratsuka, Masahiro Yano and Naoyoshi Inouchi; Effects of Variation in Starch Synthase on Starch Properties and Eating Quality of Rice; Plant Prod. Sci., 11 (4), 472-480 (2008) Rice starch (3) Jeong-Ok Kim, Wan-Soo Kim and Mal-Shick Shin, Kwangju (Korea); A Comparative Study on Retrogradation of Rice Starch Gels by DSC, X-Ray and α-Amylase Methods; Starch / Starke. 49, 71-75 (1997) Rice starch (4) "Knowledge of starch products", Toyoji Takahashi, Koshobo, 1996

  The apparatus 10 having the same configuration as in Example 1 was used, but in this example, the gap 13 between the mortars was fixed to 0.035 mm (35 μm), and the pulverization temperature was 15 ° C. (room temperature condition in which the heater 17 was not operated). , 80 ° C., 100 ° C. and 120 ° C., and the moisture content of the rice grain as the raw grain is 4.44%, 10.89%, 12.73% and 17.57% (new rice), Actual milling was performed under each union condition.

  The results of this milling treatment are shown in FIGS. 17 to 20 (wide-angle X-ray diffraction graph) and FIGS. 21 to 24 (differential scanning calorimetry graph). Similarly to the second embodiment, a numerical value α indicating the degree of pregelatinization is calculated from the above formula based on the DSC measurement results shown in FIGS. 21 to 24 and shown in FIGS. From these graphs, when the gap 13 between the dies is made as small as 0.35 mm, it is very strict to advance the pregelatinization, but when raw rice grains having a high water content of 17.57% are used, 80 ° C. or higher The rice flour completely alphalated (α = 100) could be obtained by pulverizing under the following temperature conditions.

  In this example, dispersibility and machinery when fully pregelatinized rice flour (α = 100) obtained according to the present invention is added to PLA (polylactic acid resin) recognized as superior as a biodegradable resin. The physical properties were evaluated. FIG. 32 shows that when fully pregelatinized rice flour according to the present invention is added to PLA, pregelatinized rice (hereinafter referred to as “commercially pregelatinized rice flour”) obtained by dewatering and cooking after conventional rice cooking is added. In the case, it is a graph which shows the result of having measured the stress at the time of a fracture | rupture (breaking stress) by performing a uniaxial tension test about each of the case where raw rice flour (beta rice flour) is added, and the case where it does not add (PLA simple substance). The vertical axis represents the breaking stress, and the horizontal axis represents the specimen. When adding rice flour, PLA / rice flour composite material was obtained by simply mixing PLA and rice flour without adding water.

In addition, since the strength of rice itself is significantly lower than that of PLA, it is considered that it does not contribute to the strength. Therefore, in the uniaxial tensile test in the case of PLA / rice flour composite material added with rice flour, the raw data of the measurement results are as follows: And converted. That is, the stress σ _{PLA in} the case of PLA alone is calculated by σ _PLA = F ₁ / A (A is a cross-sectional area, and F ₁ is the PLA tension). The stress σ _COM of the PLA / rice flour composite material is, for example, the case where the blending ratio is 50:50. In the composite material with 50% rice flour added, the ratio of PLA to the cross-sectional area can be assumed to be A / 2. Assuming F ₂ , σ _COM = F ₂ / (A / 2) = 2 × F ₂ / A, but the measured raw data for this composite material is the value of F ₂ / A, so when converted to PLA The stress σ _{COM (converted)} of the composite material after _conversion is σ _{COM (converted)} = 2 × measured value. When the amount of rice flour added was 10% and 25%, conversion was performed in the same manner as described above.

  From the results shown in FIG. 32, when the commercially available pregelatinized rice flour having a low pregelatinization level or non-pregelatinized beta rice flour was added, the tensile strength was lower than in the case of PLA alone in both 10% addition and 25% addition. On the other hand, when the fully pregelatinized rice flour according to the present invention is added, the tensile strength is improved in both 10% addition and 25% addition, and when the addition amount is increased to 50%, further remarkable tensile strength is obtained. It was confirmed that an improvement effect was obtained. This result is thought to be due to the fact that rice flour having a very high degree of pregelatinization has extremely high compatibility with PLA.

  FIG. 33 shows the result of taking a photograph for confirming the dispersibility of rice flour for each PLA / rice flour composite material used in this example. Commercially pre-gelatinized rice flour having a low degree of pregelatinization or not pregelatinized is shown. When beta rice flour is added, dispersibility is poor, whereas when fully pregelatinized rice flour according to the present invention is added, both 10% addition and 25% addition have high dispersibility with respect to PLA, It was confirmed that it was possible to add to PLA without the need to add water. This result is due to hydrogen bonds between PLA and OH groups (hydroxyl groups) in starch when starch is completely amorphized (pregelatinized) due to the presence of carboxylic acid in the PLA molecule. It is thought that this is because high compatibility is exhibited. That is, it can be considered that the fact that completely pregelatinized rice flour has very high compatibility or dispersibility greatly contributes to the improvement of mechanical properties when added to PLA.

In this example, a test was conducted to confirm that the fully pregelatinized rice flour obtained according to the present invention is excellent in enzyme reaction (saccharification) to glucose by an enzyme, which is an important characteristic during ethanol production. For comparison, beta obtained by heating to 90 ° C with commercially available pregelatinized rice flour and raw rice flour (beta rice flour) similar to Example 4 and stirring at a stirring speed of 140 rpm for 1 hour and then cooling to 50 ° C. Added rice flour. These rice flours were saccharified and the glucose concentration of the obtained saccharified product was measured. The experimental conditions are as follows.
(1) A substrate solution obtained by adding 60 ml of pure water to 15 g of each rice flour as a sample.
(2) 2.25 mg of enzyme (Uniase BM-8) was added to this substrate solution to start the reaction. The reaction was carried out using a 200 ml three-necked flask equipped with a reflux tube and a glass stopper at a temperature of 50 ° C. and a stirring speed of 140 rpm.
(3) After 1 hour, 9 mg of another enzyme (Uniase 30) was added, and the reaction was continued at a temperature of 60 ° C.
(4) The reaction solution was taken into a sample tube at a fixed time (after 0.5, 1, 2, 3, 6, 12, 24 hours), and subjected to centrifugal solid-liquid separation at 4000 rpm for 10 minutes.
(5) 100 μl of the liquid fraction was diluted 50 times with a 5 ml volumetric flask.
(6) The sugar concentration of the diluted solution was measured using a glucose kit.

  From the results shown in FIG. 34, it was confirmed that the fully pregelatinized rice flour according to the present invention exhibits significantly higher saccharification properties than other samples. This suggests that ethanol can be obtained in a high yield by using, for example, the fully pregelatinized rice flour according to the present invention as a raw material for ethanol production.

  The apparatus shown in FIGS. 1 and 2 is only an example that can be used to carry out the method of the present invention, and any other apparatus that can perform the method of the present invention may be used. For example, as an apparatus for pulverizing raw material grains by applying shearing force, in addition to the illustrated mortar apparatus used in the embodiment, the raw grain is passed through a minute gap between two relatively rotating rollers. A small gap between the outside of the small-diameter member and the inside of the large-diameter member by rotating and relatively rotating a small-diameter cylindrical or columnar member and a large-diameter cylindrical member concentrically It is possible to adopt an apparatus configuration that shears and pulverizes while passing raw material grains.

  The present invention is useful as a novel technique for producing highly pregelatinized starch powder without water addition, efficiently, in a short time, and at low cost. The pregelatinized starch powder mentioned here covers all grains such as rice, wheat, soybeans, red beans, buckwheat, potatoes, beans, corn, etc., which are mainly composed of starch. These can be alpha-milled in time. Therefore, processing that previously required a previous process such as boiling, such as koji from red beans, mashed potatoes from potatoes, etc., can be made only by adding cold water, and can be manufactured without the process of boiling Become.

  The highly pregelatinized starch powder is expected to be used not only in the conventional food field but also in various fields. For example, because it exhibits good dispersibility and compatibility with plastics such as PLA, it not only eliminates the need to use plasticizers such as water and glycerin, but also improves the mechanical properties. Therefore, it is also effective as a plastic additive.

  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 need for all the processing processes that required the previous step of cooking, and it has a very wide range of applications. . For example, if the pregelatinized starch powder obtained from the present invention is used for saccharification of starch when synthesizing lactic acid which is a raw material of biodegradable resin, plastic / starch composite material, etc. Since the pre-process is not necessary and the alpha conversion process such as rice cooking required by the conventional technology can be omitted, 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.

  As described above, the pregelatinized starch powder obtained in the present invention can be widely applied not only as a food product but also as an industrial material, and the present invention can be used extremely widely in a wide range of industrial fields. Have sex.

DESCRIPTION OF SYMBOLS 10 Flour mill 11 Upper mill 11a Inner surface 11b Bottom surface 11c Tapered raw material path 12 Lower mill 13 Gap 14 Raw material inlet 15 Motor 16 Gap adjustment part 17 Heater 18 Heater cord 19 Temperature controller 21 Data cable 22 Computer 23 Data cable 24 Temperature control cable 25 Motor control cable 26 Receptacle 27 Flour drop port 28 Flour drop chute 29 Housing part

Claims (10)

In the differential scanning calorimetry, when the endothermic enthalpy accompanying melting of a standard sample that has not been converted to alpha is ΔH _max , the numerical value α represented by α = (1−ΔH _T / ΔH _max ) × 100 is 80 or more. A pregelatinized starch powder having an endothermic enthalpy ΔH _T at the same melting temperature. The method for producing pregelatinized starch powder according to claim 1, wherein the gap between the two relatively moving members is set to less than 0.02 mm, and the raw material grain is put into the gap and pulverized by applying a shearing force. . 2. The method for producing pregelatinized starch powder according to claim 1, wherein the gap between the two relatively moving members is set to 0.01 mm or less, and the raw material grains are put into the gap to be pulverized by applying a shearing force. . 2. The alpha according to claim 1, wherein the gap between the two relatively moving members is less than 0.02 mm, and the raw material grain is put into the gap and is pulverized by applying a shearing force at a temperature of 80 ° C. or higher. A method for producing a modified starch powder. A gap between two relatively moving members is set to less than 0.04 mm, and raw material grains having a moisture content of 15% or more are put into the gap, and are pulverized by applying a shearing force at a temperature of 80 ° C. or more. The manufacturing method of the pregelatinized starch powder of Claim 1. A gap between two relatively moving members is set to 0.01 mm or less, raw material grains having a water content of 12% or more are put into the gap, and a shearing force is applied at a temperature of 80 ° C. or more to be pulverized. The manufacturing method of the pregelatinized starch powder of Claim 1. In a method for producing pregelatinized starch powder by putting raw grain into a gap between two relatively moving members and applying a shearing force to pulverize, the size of the gap, the temperature during shear grinding and the By combining and setting the three conditions of moisture content, the endothermic enthalpy accompanying melting of the standard sample that is not pregelatinized in differential scanning calorimetry is ΔH _max , and the endothermic enthalpy at the same melting temperature of the pregelatinized starch produced Δ method for producing a pregelatinized starch powder and controlling a numerical value represented by _{α = (1- △ H T /} △ H max) × 100 when the H _T alpha. A plastic additive mainly comprising the pregelatinized starch powder according to claim 1. A composite material obtained by adding the pregelatinized starch powder according to claim 1 to a biodegradable resin. A composite material obtained by adding the pregelatinized starch powder according to claim 1 to a polylactic acid resin.

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