Method for producing pregelatinized starch dry powder, pregelatinized starch dry powder, pregelatinized buckwheat dry powder, and production apparatus for pregelatinized starch dry powder

Abstract

The present invention addresses the problem of providing a method and device for producing a novel gelatinized starch dry powder. The present invention further addresses the problem of providing a gelatinized starch dry powder having novel properties (for example, good processing properties).　The present invention provides a method for producing a gelatinized starch dry powder, said method comprising a step for supplying cereal grains to a production device equipped with a preset milling mechanism and temperature control means and milling the cereal grains under shear conditions.

Description

Technical Field

[0001] The present invention relates to a method for producing pregelatinized starch dry powder, pregelatinized starch dry powder, pregelatinized buckwheat dry powder, and an apparatus for producing pregelatinized starch dry powder.

Background Art

[0002] Pregelatinized starch dry powder is usually obtained by adding water to starch and then heating and drying it (for example, Patent Document 1). Pregelatinized starch dry powder can be eaten by simply adding water and kneading it moderately without cooking, and its application range is wide. Note that the gelatinization of starch that occurs when starch is heated with water is called "pregelatinization."

[0003] Regarding the composition of starch, a technique is known in which a mixture of heated rice and water is ground in a stone mortar grinder in a humid state to decompose and reduce the molecular weight of much of the amylopectin contained in the rice (Patent Document 2).

[0004] On the other hand, the production of pregelatinized starch dry powder requires a process of adding water and heat to raw grains (β-grains = crystalline) to pregelatinize them (α-grains = amorphous), followed by drying and then milling. Therefore, there has been a problem that the production process is long and complicated, and the production cost is high. Based on this, from the perspective of cost reduction and the like, methods for producing pregelatinized starch dry powder without adding water have also been proposed. For example, in Patent Document 3 , a production method has been proposed in which grains are heated to a temperature of 80°C or higher while simultaneously applying shear to obtain pregelatinized flour.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

[0006] However, the production of dry powder of pregelatinized starch has the following problems. The degree of gelatinization can decrease due to the fixation of the grain grinding section and the resulting wear caused by strong contact between the grain and the grinding section. · If foreign matter gets mixed in with the grain, damage to the grinding section may occur.

[0007] Furthermore, the obtained pregelatinized starch dry powder also had problems with processing characteristics due to the difficulty in maintaining and adjusting the elasticity and viscosity.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a novel method and apparatus for producing a dry powder of pregelatinized starch. Another object of the present invention is to provide a pregelatinized starch dry powder having novel properties (for example, good processing properties). [Means for solving the problem]

[0009] The present inventors have discovered that the above-mentioned problems can be solved by grinding grains using a rigid member whose gap distance is adjusted to be variable in the production of a pregelatinized starch dry powder, and have completed the present invention. Specifically, the present invention provides the following.

[0010] (1) A method for producing a dry powder of pregelatinized starch, comprising: The method includes subjecting grains to a manufacturing device having a crushing mechanism and a temperature adjusting means, and crushing the grains under shear conditions; The crushing mechanism includes: At least two rigid members arranged opposite to each other; a pressing member that presses at least one of the rigid members so that a gap between the rigid members is variable by a force from an opposing surface side of the rigid members, The temperature adjusting means adjusts the temperature of the grains during the process of being sheared by the grinding mechanism, The rigid member is arranged so as to be able to shear and crush the grains supplied to the gap formed by the opposing surfaces of the rigid member. Manufacturing method.

[0011] (2) Pre-gelatinized starch dry powder that satisfies all of the following requirements. (Requirement 1A) In gel filtration chromatography, it has at least three peaks indicating starch. (Requirement 1B) In the at least three peaks, the intensity of the first peak from the high molecular weight side is lower than that of the third peak from the high molecular weight side. (Requirement 1C) The crystallinity is 22.5% or less.

[0012] (3) Pre-gelatinized starch dry powder that satisfies all of the following requirements. (Requirement 2A) In gel filtration chromatography, it has at least three regions indicating starch. Among the three regions, when the region from 120 minutes or more to less than 145 minutes is defined as "A", the region from 145 minutes or more to less than 190 minutes is defined as "B", and the region from 190 minutes or more to less than 250 minutes is defined as "C", both of the following formulas (1) and (2) are satisfied. A / (A + B + C)>0.05 Formula (1) C / (A + B + C)>0.2 Formula (2) [[ID=XX]] (Requirement 2B) The crystallinity is 22.5% or less.

[0013] (4) In the loss elastic modulus in the gelation test, the maximum value at the peak that appears between a shear strain of 0.03 and 0.25 is larger than the value at a shear strain of 0.001, the pre-gelatinized starch dry powder according to (2) or (3).

[0014] (5) A 14% by mass aqueous solution of the pre-gelatinized starch dry powder has a viscosity of 30 Pa·s or more and 500 Pa·s or less at 35°C, and the viscosity immediately after heating the aqueous solution at 95°C for 5 minutes is 300 Pa·s or more, the pre-gelatinized starch dry powder according to (2) or (3).

[0015] (6) The pre-gelatinized starch dry powder according to (2) or (3), wherein the viscosity of a 14% by mass aqueous solution of the pre-gelatinized starch dry powder immediately after heating at 95°C for 5 minutes is 1000 Pa·s or more.

[0016] (7) The pre-gelatinized starch dry powder according to (2) or (3), having a moisture content of 12.5% by mass or less.

[0017] (8) The pre-gelatinized buckwheat dry powder having a crystallinity of 18.0% or less.

[0018] (9) The pre-gelatinized buckwheat dry powder having a moisture content of 12.5% by mass or less.

[0019] (10) The pre-gelatinized buckwheat dry powder according to (8) or (9), wherein the maximum value at the peak that appears between a shear strain of 0.03 and 0.25 in the loss modulus in the gelation test is 1.30 times or more greater than the value at a shear strain of 0.001.

[0020] (11) A production apparatus for pre-gelatinized starch dry powder, comprising a pulverizing mechanism and a temperature adjusting means, wherein the pulverizing mechanism has at least two rigid members arranged opposite to each other, and a pressing member that presses at least one of the rigid members so that the gap distance between the rigid members can be varied by the force from the opposite surface side of the rigid members, the temperature adjusting means adjusts the temperature of the grain during the process of being sheared by the pulverizing mechanism, the rigid members are arranged so as to be able to shear and pulverize the grains supplied to the gap formed by the opposing surfaces of the rigid members, Production apparatus.

Advantages of the Invention

[0021] According to the present invention, a novel method and apparatus for producing pre-gelatinized starch dry powder are provided. Furthermore, according to the present invention, pre-gelatinized starch dry powder having novel properties (for example, good processing properties) is provided.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

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Figure 8

Mode for Carrying Out the Invention

[0023] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not particularly limited thereto.

[0024] <Method for Producing Pregelatinized Starch Dry Powder> The method for producing a pregelatinized starch dry powder of the present invention (hereinafter, also referred to as "the production method of the present invention") satisfies all of the following requirements. · A step of subjecting grains to a production apparatus equipped with a pulverizing mechanism and a temperature adjusting means and pulverizing them under shear conditions is included. · The pulverizing mechanism has at least two rigid members arranged opposite to each other and a pressing member that presses at least one of the rigid members so that the gap interval between the rigid members can be changed by the force from the opposite surface side of the rigid member. · The temperature adjusting means adjusts the temperature of the grains during the process of being sheared by the pulverizing mechanism. The rigid members are arranged so as to be able to shear and crush grains fed into a gap formed by opposing surfaces of the rigid members.

[0025] A conventional method for producing dry powder of pregelatinized starch is known, in which two mortars are fixed to a shaft and grains placed between them are ground and pulverized by the rotation of the mortars (for example, Japanese Patent No. 4767128). In such conventional methods, the particle size, degree of gelatinization, degree of crystallinity, etc. of the grain flour were adjusted by adjusting and fixing the distance between the mortars.

[0026] However, in a grinder using a fixed mortar, the opposing mortars are pressed and fixed together to grind the grains, which can result in a decrease in gelatinization degree due to the resulting wear. In this case, even if the mills are fixed with a gap between them, if foreign matter larger than the gap is mixed into the grain, the device may stop or the mills may be damaged, which is unlikely to solve the problem. Furthermore, it is difficult to fine-tune the spacing between the mills while taking into account the characteristics of the target grain, making it difficult to obtain flour with the desired properties.

[0027] Therefore, the inventors conducted extensive research and found that if grinding is performed under shear conditions with the gap between the mortars being variable, the pressure applied to the grains becomes variable, which makes it possible to protect the mortar (grinding section) and improve grinding efficiency.For example, by making the mortar movable, the grains are ground while being pressed down with pressure, and if foreign matter (for example, matter of excessive size or hardness) gets mixed in, a gap opens up, allowing the foreign matter to be expelled and protecting the device. Therefore, the manufacturing method of the present invention can easily deal with foreign matter. Furthermore, since the manufacturing method of the present invention can be introduced into large machines equipped with a pressurizing mechanism, it can also deal with foreign matter during mass production.

[0028] Furthermore, the inventors have also found that when pulverization is carried out under shear conditions with the gap distance between the mortars in a variable state, surprisingly, an α-starch dry powder having novel properties can be produced by adjusting the pressure. Specifically, this α-starch dry powder is excellent in elasticity and in maintaining and adjusting viscosity, and has good processing characteristics. The reason is not clear, but it is presumed as follows. When shear pressure is applied to the cereal powder with the gap distance between the mortars in a variable state, the molecular weight distribution of the α-starch dry powder constituting the powder broadens compared with the conventional method using a fixed mortar (Figure 3). Specifically, in the conventional method, since the shear pressure does not vary, the molecular weight of the obtained α-starch dry powder tends to concentrate on small molecular weights. On the other hand, in the α-starch dry powder obtained by pulverization under shear conditions with the gap distance between the mortars in a variable state, it is distributed to both large and small molecular weights. According to the resulting α-starch dry powder, for example, it becomes easier to produce a gel having good "firmness" described later. As a result of the study by the inventors, it was found that the α-starch dry powder having a broad molecular weight distribution can achieve, for example, good processing characteristics and appropriate firmness described later.

[0029] Hereinafter, the production method of the present invention will be described in detail.

[0030] (1) Pulverization mechanism The pulverization mechanism has at least a rigid member and a pressing member.

[0031] In the present invention, the "rigid member" is a member that is arranged such that at least two are opposed to each other and shears and pulverizes the cereal grains supplied therebetween.

[0032] The gap distance between the arranged rigid members can preferably be 0 to 30 mm, more preferably 0 to 1 mm, in a state where no cereal grains are supplied, from the viewpoint of facilitating the realization of sufficient shear. However, this gap distance varies as described later.

[0033] The rigid member can be of any shape, material, etc. that is conventionally employed as a mortar or a roller in known devices.

[0034] In the present invention, the "pressing member" is disposed on the side opposite to the opposing surfaces of the two rigid members and varies the gap distance between the rigid members. However, the gap distance varies depending on the force generated from the opposing surface side of the rigid member (for example, the force generated during the pulverization of grain).

[0035] The pressing member can be any biasing means (for example, a spring). In the present invention, the pressure applied from the rigid member to the grain is adjusted by the pressing member, and pulverization under shear conditions is realized.

[0036] The lower limit of the load applied to the grain by the biasing means is preferably 15 kN / m or more, more preferably 20 kN / m or more, and even more preferably 30 kN / m or more from the viewpoint of sufficiently shearing the grain and easily obtaining an α - starch dry powder that satisfies one or more of the following (Requirement 1A) and (Requirement 1C). 2 above, 2 more preferably 20 kN / m 2 above, and even more preferably 30 kN / m

[0037] The upper limit of the load applied to the grain by the biasing means is preferably 40 / m or less, more preferably 30 / m or less, and even more preferably 25 / m or less from the viewpoint of sufficiently varying the gap distance between the rigid members and easily obtaining an α - starch dry powder that satisfies one or more of the following (Requirement 1B), (Requirement 1C), (Requirement 2A), and (Requirement 2B). kN / m 2 below, more preferably 30 kN / m 2 below, and even more preferably 25 kN / m 2 below.

[0038] The number of pressing members is not particularly limited, and they may be arranged to press both of the two rigid members or to press only one of them.

[0039] The pulverization conditions of the grains by the pulverization mechanism are not particularly limited, but from the viewpoint of facilitating the realization of sufficient shearing, etc., the rigid member is preferably rotated at a shearing speed of 90 to 600 seconds -1 , more preferably 280 to 600 seconds -1 .

[0040] (2) Temperature adjustment means The temperature adjustment means adjusts the temperature of the grains during the process of being sheared by the pulverization mechanism.

[0041] The temperature adjustment means can be a conventionally known heater. The shearing of the grains can be carried out, for example, preferably at 80°C or higher, more preferably at 100 to 200°C, from the viewpoint of facilitating the realization of sufficient gelatinization, etc.

[0042] (3) Grains The grains used in the production method of the present invention are not particularly limited as long as they are grains mainly composed of starch, and any grains conventionally used as raw materials for gelatinized starch dry powder can be adopted. Examples of the grains include rice, buckwheat, wheat, adzuki beans, corn, etc.

[0043] (4) Other configurations Other configurations of the production apparatus can be adopted according to the purpose, etc., using conventionally known configurations (grain supply port, grain discharge port, etc.).

[0044] In the production method of the present invention, water may or may not be added to the grains. From the viewpoint of simply obtaining gelatinized starch dry powder, it is preferable that the production method of the present invention does not include the step of adding water to the grains.

[0045] (5) Gelatinized starch dry powder obtained from the production method of the present invention According to the production method of the present invention, as described above, a gelatinized starch dry powder having excellent elasticity and viscosity maintenance adjustment and good processing characteristics can be obtained. The pregelatinized starch dry powder obtained from the production method of the present invention can be, for example, the following pregelatinized starch dry powder or pregelatinized buckwheat dry powder.

[0046] <Pregelatinized starch dry powder> The pregelatinized starch dry powder of the present invention includes the following two aspects.

[0047] (Pregelatinized starch dry powder according to the first aspect) A pregelatinized starch dry powder that satisfies all of the following requirements. (Requirement 1A) In gel filtration chromatography, it has at least three peaks indicating starch. (Requirement 1B) Among the at least three peaks, the intensity of the first peak from the high molecular weight side is lower than that of the third peak from the high molecular weight side. (Requirement 1C) The crystallinity is 22.5% or less.

[0048] (Pregelatinized starch dry powder according to the second aspect) A pregelatinized starch dry powder that satisfies all of the following requirements. (Requirement 2A) In gel filtration chromatography, it has at least three regions indicating starch. Among the three regions, when the region from 120 minutes or more to less than 145 minutes is designated as "A", the region from 145 minutes or more to less than 190 minutes is designated as "B", and the region from 190 minutes or more to less than 250 minutes is designated as "C", both of the following formulas (1) and (2) are satisfied. A / (A + B + C)>0.05 Formula (1) C / (A + B + C)>0.2 Formula (2) (Requirement 2B) The crystallinity is 22.5% or less.

[0049] The above pregelatinized starch dry powder has a combination of characteristics different from those of existing pregelatinized starch dry powders (i.e., the above respective requirements). The inventors of the present invention created such a novel pregelatinized starch dry powder by the production method of the present invention.

[0050] In the present invention, the "pre-gelatinized starch dry powder" includes those obtained by pre-gelatinizing (gelatinizing, amorphizing) grains mainly composed of starch (such as rice, buckwheat, wheat, adzuki beans, corn, etc.).

[0051] Hereinafter, the pre-gelatinized starch dry powder according to each aspect will be described.

[0052] (1) Pre-gelatinized starch dry powder according to the first aspect The pre-gelatinized starch dry powder according to the first aspect (hereinafter, also referred to as the "first pre-gelatinized starch dry powder") satisfies all of (Requirement 1A) to (Requirement 1C). However, in addition to these, the first pre-gelatinized starch dry powder may further satisfy (Requirement 2A) described later, or may not satisfy it.

[0053] (1-1) Regarding Requirement 1A The first pre-gelatinized starch dry powder has at least three peaks indicating starch in its gel filtration chromatography.

[0054] In the present invention, "gel filtration chromatography" is obtained by the method shown in the examples.

[0055] In the present invention, the "peak indicating starch" can be specified by the following method. Each peak is based on the portion from the lowest value of the rising edge of the graph through the highest value to the next lowest value. However, for example, the graph may appear as a shoulder. In that case, for example, the point where the descending curve becomes gentle or the point where the ascending curve becomes gentle is taken as the boundary of the peak.

[0056] The first pre-gelatinized starch dry powder has at least three, preferably at least four, peaks indicating starch. The upper limit of the number of peaks indicating starch is not particularly limited, but is usually four or less. Also, in the present invention, the first, second, third, ··· nth peaks are distinguished by the interval of retention time (for example, from 120 minutes or more to less than 145 minutes, from 145 minutes or more to less than 190 minutes, from 190 minutes or more to less than 250 minutes).

[0057] Gel filtration chromatography of the first pregelatinized starch dry powder may have the following three peaks, although not particularly limited. Retention time of 120 minutes or more and less than 145 minutes: the first peak from the high molecular weight side Retention time of 145 minutes or more and less than 190 minutes: the second peak from the high molecular weight side Retention time of 190 minutes or more and less than 250 minutes: the third peak from the high molecular weight side

[0058] In the present invention, the "nth peak from the high molecular weight side" means the nth peak counted from the one with the shortest retention time (elution time) in chromatography. For example, the "first peak from the high molecular weight side" means the peak observed with the shortest retention time.

[0059] The first pregelatinized starch dry powder may satisfy the following range for the ratio of each peak area to the total peak area of the above three peaks. The first peak from the high molecular weight side: 5 to 30% The second peak from the high molecular weight side: 50 to 60% The third peak from the high molecular weight side: 10 to 45%

[0060] (1-2) Regarding Requirement 1B In Requirement 1A, in at least three peaks indicating starch, the first peak from the high molecular weight side has a lower intensity than the third peak from the high molecular weight side.

[0061] In the present invention, "the first peak from the high molecular weight side has a lower intensity than the third peak from the high molecular weight side" means that the value (peak height) of the first peak from the high molecular weight side is lower than the value of the third peak from the high molecular weight side. According to the production method of the present invention, it is easy to realize peaks having such a relationship. This is presumably the result of the high molecular starch being appropriately changed into a low molecular form by the shearing force.

[0062] Incidentally, the inventors found that in the pregelatinized starch dry powder obtained using the production apparatus of Japanese Patent No. 4767128 which does not have a pressing member, there are only two peaks indicating starch, and from the high molecular weight side 2 the second peak is from the high molecular weight side 1 lower than the fourth peak (for example, 2 the sixth peak is 1 half or less of the eighth peak). This was confirmed (see "Comparative Example: Conventional Method" in Figure 2).

[0063] In the first pregelatinized starch dry powder, the first peak from the high molecular weight side has a lower intensity than the third peak from the high molecular weight side, preferably 0.5 times or less, more preferably 0.4 times or less.

[0064] (1-3) Regarding Requirement 1C The crystallinity of the first pregelatinized starch dry powder is 22.5% or less. That is, the first pregelatinized starch dry powder has a high proportion of amorphous parts.

[0065] The upper limit of the crystallinity of the first pregelatinized starch dry powder is 22.5% or less, preferably 20.0% or less, more preferably 17.0% or less, or 14.0% or less.

[0066] The lower limit of the crystallinity of the first pregelatinized starch dry powder is preferably 1.0% or more, more preferably 2.0% or more, still more preferably 4.0% or more, still more preferably 7.0% or more, still more preferably 12.0% or more.

[0067] In the present invention, "crystallinity" is specified by the method shown in the examples.

[0068] (2) Pregelatinized starch dry powder according to the second aspect The pregelatinized starch dry powder according to the second aspect (hereinafter, also referred to as "the second pregelatinized starch dry powder") satisfies all of (Requirement 2A) and (Requirement 2B). However, in addition to these requirements, the second pregelatinized starch dry powder may or may not further satisfy (Requirement 1B).

[0069] Hereinafter, the requirements that overlap with those for the first pregelatinized starch dry powder will be omitted from the description as appropriate.

[0070] (2-1) Regarding Requirement 2A The second pregelatinized starch dry powder has at least three regions indicating starch in its gel filtration chromatography. Among the above three regions, when the region from 120 minutes or more to less than 145 minutes is designated as "A", the region from 145 minutes or more to less than 190 minutes is designated as "B", and the region from 190 minutes or more to less than 250 minutes is designated as "C", both of the following formulas (1) and (2) are satisfied. A / (A + B + C)>0.05 Formula (1) C / (A + B + C)>0.2 Formula (2)

[0071] Each of the above regions may correspond to the peak area in gel filtration chromatography. For example, region "A" may correspond to the peak area from 120 minutes or more to less than 145 minutes. Region "B" may correspond to the peak area with a retention time from 145 minutes or more to less than 190 minutes. Region "C" may correspond to the peak area with a retention time from 190 minutes or more to less than 250 minutes.

[0072] The pregelatinized starch dry powder that satisfies the above formula means that the proportion of low-molecular-weight starch is higher than that of high-molecular-weight starch. According to the production method of the present invention, it is easy to realize a molecular weight distribution in such a relationship. This is presumably the result of the high-molecular-weight starch being appropriately changed into a low-molecular form by the shearing force.

[0073] In formula (1), the lower limit of "A / (A + B + C)" is more than 0.05, preferably 0.08 or more, and more preferably 0.1 or more. In formula (1), the upper limit of "A / (A + B + C)" is preferably 0.45 or less, and more preferably 0.40 or less.

[0074] In formula (2), the lower limit of “C / (A + B + C)” is more than 0.2, preferably 0.25 or more, and more preferably 0.30 or more. In formula (2), the upper limit of “C / (A + B + C)” is preferably 0.90 or less, and more preferably 0.80 or less.

[0075] In Requirement 2A, “B / (A + B + C)” is not particularly limited, but it may satisfy the following requirements. The lower limit of “B / (A + B + C)” is preferably 0.15 or more, and more preferably 0.20 or more. The upper limit of “B / (A + B + C)” is preferably 0.70 or less, and more preferably 0.60 or less.

[0076] (2 - 2) Regarding Requirement 2B The crystallinity of the second pregelatinized starch dry powder is 22.5% or less. The details of (Requirement 2B) are the same as those of (Requirement 1C).

[0077] (3) Other requirements Regarding the first and second pregelatinized starch dry powders, other requirements are not particularly limited, but by satisfying any one or all of the following requirements, it is easier to obtain a pregelatinized starch dry powder with better processing characteristics.

[0078] (3 - 1) Loss modulus Regarding the loss modulus in the gelation test of the pregelatinized starch dry powder, it is preferable that the maximum value at the peak that appears between a shear strain of 0.03 and 0.25 is larger than the value at a shear strain of 0.001.

[0079] It is common knowledge that the loss modulus of the pregelatinized starch dry powder decreases over time in the gelation test. However, the pregelatinized starch dry powder of the present invention goes against such common knowledge and the loss modulus is likely to temporarily increase (see Figures 5 and 7).

[0080] In addition, in the pregelatinized starch dry powder obtained using the manufacturing apparatus of Japanese Patent No. 4767128 that does not have a pressing member, immediately after production, although it exhibits a certain loss modulus at small strains, when the strain increases (for example, at a strain near 0.1), the loss modulus does not increase. Such behavior results in a reduction of so-called "firmness". Furthermore, after storage (aging), the loss modulus rapidly increases and it becomes hard.

[0081] On the other hand, according to the pregelatinized starch dry powder of the present invention that satisfies the above requirements, surprisingly, even when the strain is large, the loss modulus is likely to increase (see FIGS. 5 and 7). Therefore, according to the pregelatinized starch dry powder of the present invention, a gel with firmness can be easily produced. It was also found that in the pregelatinized starch dry powder of the present invention, even after storage, a rapid change in the loss modulus is suppressed.

[0082] In the present invention, the "gelation test" is carried out by the method shown in the examples.

[0083] (3-2) Viscosity The pregelatinized starch dry powder may satisfy any one or both of the following. (Viscosity Requirement 1) A 14 mass% aqueous solution of the pregelatinized starch dry powder has a viscosity of 30 Pa·s or more and 500 Pa·s or less at 35°C, and the viscosity immediately after heating the aqueous solution at 95°C for 5 minutes is 300 Pa·s or more. (Viscosity Requirement 2) The viscosity immediately after heating a 14 mass% aqueous solution of the pregelatinized starch dry powder at 95°C for 5 minutes is 1000 Pa·s or more.

[0084] Normal starch dry powder does not absorb water and does not generate viscosity even when water is added, but pregelatinized starch dry powder absorbs water and generates viscosity. However, the viscosity of pregelatinized starch dry powder has conventionally been difficult to adjust and has poor handling characteristics. For this reason, conventionally, crystalline starch has been blended with pregelatinized starch dry powder to adjust the viscosity.

[0085] In contrast, the gelatinized starch dry powder of the present invention can satisfy the above viscosity characteristics. Therefore, in particular, the initial viscosity can be easily adjusted, and the viscosity after heat processing can also be adjusted. For example, the gelatinized starch dry powder of the present invention that satisfies the above viscosity characteristics is suitable for the following uses. ·Bread making, etc., which require appropriate viscosity maintenance and workability from molding to baking. ·Noodle making, etc., which can be processed without using a binder and can achieve various textures (firmness, chewiness, etc.).

[0086] The viscosity of the gelatinized starch dry powder can be specified by the viscosity profile over time. In the present invention, the "viscosity profile over time" means data indicating viscosity changes accompanying temperature changes over time. More specifically, the viscosity profile over time is specified by the method shown in the examples.

[0087] Regarding (viscosity requirement 1), the viscosity at 35°C is 30 Pa·s or more and 500 Pa·s or less, preferably 70 Pa·s or more and 400 Pa·s or less.

[0088] Regarding (viscosity requirement 1), the viscosity immediately after heating at 95°C for 5 minutes is 300 Pa·s or more, preferably 350 Pa·s or more. The upper limit is not particularly limited, but is usually 1300 Pa·s or less.

[0089] Regarding (viscosity requirement 2), the viscosity immediately after heating at 95°C for 5 minutes is 1000 Pa·s or more, preferably 1250 Pa·s or more. The upper limit is not particularly limited, but is usually 2000 Pa·s or less.

[0090] (3 - 3) Moisture content The moisture content of the gelatinized starch dry powder is preferably 12.5% by mass or less, more preferably 10.0% by mass or less, and even more preferably 8.0% by mass or less.

[0091] In the present invention, the "moisture content" is the total amount of moisture contained in the gelatinized starch dry powder. The moisture content can be specified by a moisture meter (such as an infrared moisture meter).

[0092] (4) Use The use of the pregelatinized starch dry powder of the present invention is not particularly limited, and it can be used for any use such as the same uses as the conventionally known pregelatinized starch dry powder (foods, pharmaceuticals, etc.). As described above, since the pregelatinized starch dry powder of the present invention has excellent processing characteristics, it can be used as a good substitute for the conventionally used pregelatinized starch dry powder.

[0093] <Pregelatinized buckwheat dry powder> The present inventors have found the following novel pregelatinized buckwheat dry powder. The pregelatinized buckwheat dry powder can be obtained, for example, by applying the production method of the present invention to buckwheat grains.

[0094] (Pregelatinized buckwheat dry powder according to the first aspect) A pregelatinized buckwheat dry powder having a crystallinity of 18.0% or less. The upper limit of the crystallinity of the pregelatinized buckwheat dry powder is 18.0% or less, preferably 15.0% or less. The lower limit of the crystallinity of the pregelatinized buckwheat dry powder is preferably 1.0% or more, more preferably 2.0% or more, still more preferably 4.0% or more, still more preferably 7.0% or more, and still more preferably 12.0% or more.

[0095] (Pregelatinized buckwheat dry powder according to the second aspect) A pregelatinized buckwheat dry powder having a water content of 12.5% by mass or less. The upper limit of the water content of the pregelatinized buckwheat dry powder is 12.5% by mass or less, preferably 10.0% by mass or less. The lower limit of the water content of the pregelatinized buckwheat dry powder is preferably 3.0% by mass or more, more preferably 5.0% by mass or more.

[0096] In any aspect, it is preferable that the maximum value at the peak that appears between a shear strain of 0.03 and 0.25 of the pregelatinized buckwheat dry powder is 1.30 times or more larger than the value at a shear strain of 0.001, and more preferably 1.31 times or more larger. Note that the upper limit in the above is not particularly limited, but is usually 1.50 times or less.

[0097] <Apparatus for producing gelatinized starch dry powder> The present invention also includes an apparatus for producing gelatinized starch provided with the following pulverizing mechanism and temperature adjusting means. In the production apparatus, the pulverizing mechanism includes at least two rigid members arranged to face each other, and a pressing member that presses at least one of the rigid members so that the gap distance between the rigid members can be varied by a force from the facing surface side of the rigid members. The temperature adjusting means adjusts the temperature of the grain during the process of being sheared by the pulverizing mechanism. The rigid members are arranged so as to be able to shear and pulverize the grains supplied to the gap formed by the facing surfaces of the rigid members.

[0098] The form of the apparatus for producing gelatinized starch of the present invention can be a mortar mill (for example, an apparatus having the configuration of FIG. 1).

[0099] In a preferred embodiment of the present invention, the gelatinized starch dry powder of the present invention is obtained by subjecting grains to the above production apparatus and pulverizing them under shearing conditions.

Examples

[0100] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0101] <Production of gelatinized starch dry powder (gelatinized rice dry powder)> By the following method, grains were pulverized with a mortar mill to produce a gelatinized starch dry powder.

[0102] (1) Preparation of mortar mill A small temperature-controlled mortar mill was prepared. This pulverizer has the same structure as the apparatus shown in FIG. 1 of Japanese Patent No. 4767128. Specifically, it includes a pulverizing mechanism provided with an upper mortar and a lower mortar (corresponding to rigid members) arranged to face each other, temperature adjusting means capable of adjusting the temperature of the upper mortar, a grain supply port, a grain discharge port, etc. In this crusher, the grains supplied to the grain supply port are supplied to the gap space between the upper and lower mortars, and are crushed by the action of the upper and lower mortars. The crushed material (gelatinized starch dry powder) can be recovered from the grain outlet.

[0103] The upper and lower mortars of this crusher are fixed in position, and the lower mortar rotates horizontally with respect to the opposing surface with the upper mortar, applying a shearing force to the grains. In this example, a spring (corresponding to a pressing member) is provided under the lower mortar and modified to be movable also in the vertical direction with respect to the opposing surface with the upper mortar.

[0104] The spring has a surface pressure of the load (load per unit area) in the range of 9.70 kN / m 2 ~56.80 kN / m 2 is used. The higher the value of the load, the more difficult it is to vary the gap distance between the upper and lower mortars.

[0105] A schematic diagram of the mortar crusher used in this example is shown in Fig. 1.

[0106] (2) Shearing of Grains As grains, rice produced in Yamagata Prefecture in Reiwa 2 year, "Hae-nuki" 」 to was prepared. These grains were supplied to the mortar crusher and sheared and crushed at the gap (about 0 mm) between the upper and lower mortars. In this example, no water was added to the grains. The obtained crushed material corresponds to gelatinized starch dry powder (gelatinized rice dry powder). The temperature of shearing was set at 120 °C. The shearing speed was set at 500 sec -1 to.

[0107] (3) Analysis of Gelatinized Starch Dry Powder For the obtained gelatinized starch dry powder (gelatinized rice dry powder), gel filtration chromatography analysis, measurement of crystallinity, measurement of moisture content, and gelation test were performed.

[0108] (3-1) Gel Filtration Chromatography Analysis To 20 mg of α - starch dry powder, 1.6 mL of distilled water was added, and after suspension with a homogenizer, 0.4 mL of 5M NaOH was added and stirred, followed by gelatinization at 37°C for 30 minutes. Subsequently, 2 mL each of distilled water and eluent (0.05M NaOH / 0.2% NaCl) were added, mixed, and the filtrate through a 5 - μm filter was prepared as a sample solution. 5 mL of the sample solution was applied to a gel - filtration column (Toyopearl HW75S×2 - 65S - 55S, Φ2 cm×30 cm×4 columns), and gel - filtration was carried out under the conditions of an eluent of 0.05M NaOH / 0.2% NaCl and a flow rate of 1 mL / min. Detection was performed using an IR detector, and the detection values from 100 minutes to 260 minutes were used.

[0109] Gelatinization starch The results of gel - filtration chromatography analysis of the dry powder (gelatinized rice dry powder) are shown in Figure 2.

[0110] In Figure 2, "Comparative Example, Conventional Method" means the gelatinized rice dry powder obtained in the same manner as in the examples of Japanese Patent No. 4767128. In Figure 2, the unit "kN / m^2 " represents the load per unit area (m 2 ) applied between the upper and lower mortars. The same applies to the unit "kN / m^2 " hereinafter. In Figure 2, "Normal rice flour" means the rice dry powder obtained without shearing the grains.

[0111] As shown in Figure 2, when a load of "43.09 kN / m^2" was used, at least three peaks indicating starch were recognized (elution time: from 120 minutes or more to less than 145 minutes, from 145 minutes or more to less than 190 minutes, and from 190 minutes or more to less than 250 minutes). Also, the first peak from the high - molecular - weight side (elution time: from 120 minutes or more to less than 145 minutes) was low stronger than the third peak from the high - molecular - weight side (elution time: from 190 minutes or more to less than 250 minutes). Therefore, when using a load of "43.09 kN / m^2", pregelatinized starch dry powders that satisfy (Requirement 1A) and (Requirement 1B) were obtained.

[0112] Furthermore, among the above three regions, when the region from 120 minutes or more to less than 145 minutes is defined as "A", the region from 145 minutes or more to less than 190 minutes is defined as "B", and the region from 190 minutes or more to less than 250 minutes is defined as "C", since both of the following formulas (1) and (2) were satisfied, it was found that when using a spring with a load of "43.09 kN / m^2", (Requirement 2A) was also satisfied. A / (A + B + C)>0.05 Formula (1) C / (A + B + C)>0.2 Formula (2)

[0113] In contrast, as shown in Figure 2, when using a load of "11.75 kN / m^2", no peak was observed from 145 minutes or more to less than 190 minutes. until only The peak is was not recognized. Therefore, when using a load of "11.75 kN / m^2", pregelatinized starch dry powders that do not satisfy (Requirement 1A), (Requirement 1B), and (Requirement 2A) were obtained.

[0114] Furthermore, regarding the gel filtration chromatography of the pregelatinized dry powder (pregelatinized rice dry powder) obtained by changing the load of the spring, the results of the ratio of each peak area to the total of the three peak areas are shown in Figure 3. starch In Figure 3, "crystalline rice powder" means rice dry powder obtained without shearing the grain.

[0115] In Figure 3, the numerical value represented by the unit "kN / m^2" means the load of the spring used. In Figure 3, "conventional method" means pregelatinized rice dry powder obtained in the same manner as in the examples of Japanese Patent No. 4767128. In Figure 3, "Prior Art Document 2 Example 1" means pregelatinized rice puree obtained in the same manner as in Example 1 of Japanese Patent Application Laid-Open No. 2017-163849. In Figure 3, "Prior Art Document 2 Example 1" means pregelatinized rice puree obtained in the same manner as in Example 1 of Japanese Patent Application Laid-Open No. 2017-163849. In FIG. 3, "Prior Art Document 2, Example 2" means an α - rice puree obtained in the same manner as Example 2 of Japanese Patent Application Laid - Open No. 2017 - 163849. In FIG. 3, "1st", "2nd", and "3rd" respectively mean the region from 120 minutes or more to less than 145 minutes, the region from 145 minutes or more to less than 190 minutes, and the region from 190 minutes or more to less than 250 minutes.

[0116] As shown in FIG. 3, the higher the load, the more the molecular weight distribution changes. When using a spring of "26.64 kN / m^2" or more, the first peak area (elution time: from 120 minutes or more to less than 145 minutes) is from the high - molecular - weight side, and the third peak area (elution time: from 190 minutes or more to less than 250 minutes) from the high - molecular - weight side is narrow .

[0117] Thus, it is an unexpected finding that the gel - filtration chromatography of the α - starch dry powder obtained is completely different depending on whether the gap distance between the rigid members is made variable by the force from the facing surface side of the rigid members during shearing.

[0118] (3 - 2) Measurement of crystallinity Based on the measurement results of wide - angle X - ray diffraction, the peaks were separated into amorphous scattering and crystal reflection. The integral value of the peak due to amorphous scattering obtained was designated as "S a ", and the integral value of the peak due to crystal reflection was designated as "S c ", and the crystallinity of the α - starch dry powder was calculated based on the following formula. Crystallinity (%)=(Sc / (Sc + Sa))×100

[0119] (Measurement conditions for wide - angle X - ray diffraction) Measuring instrument: "RINT - RAPID", manufactured by Rigaku Corporation Scan speed: 4° / min Measurement angle: 5 - 35° Tube voltage: 40 kV Tube current: 30 mA

[0120] Figure 4 plots the relationship between the load of the spring used for shearing and the crystallinity of the obtained pregelatinized starch dry powder (pregelatinized rice dry powder). In Figure 4, the result with a load of "0" is the result of shearing without using a spring.

[0121] As shown in the result using the load of "43.09 kN / m^2" in Figure 4, the crystallinity was approximately 1.29%. Therefore, when using the load of "43.09 kN / m^2", as described above, a pregelatinized starch dry powder that satisfies not only (Requirement 1A), (Requirement 1B), and (Requirement 2A), but also (Requirement 1C) and (Requirement 2B) was obtained. Also, when using a load of "11.75 kN / m^2" or more, a pregelatinized starch dry powder that satisfies (Requirement 1C) and (Requirement 2B) was easily obtained.

[0122] Also, as shown in Figure 4, at loads of "43.09 kN / m^2", "48.97 kN / m^2", and "56.81 kN / m^2", the crystallinities were approximately 1.2%, approximately 1.5%, and approximately 1.5% respectively, and all satisfied (Requirement 1C) and (Requirement 2B).

[0123] On the other hand, when using a load of "9.79 kN / m^2" or less, not only did it not satisfy (Requirement 1C) and (Requirement 2B), but also since the amorphization was not sufficient, a pregelatinized starch dry powder with inferior various properties was obtained. Although not shown in the figure, these pregelatinized starch dry powders were either pregelatinized starch dry powders with a crystallinity exceeding 12% (pregelatinized starch dry powders with low amorphousness) or pregelatinized starch dry powders with a crystallinity of less than 1% (pregelatinized starch dry powders with excessive amorphousness). Also, when obtaining a pregelatinized starch dry powder with a crystallinity of less than 1%, very strong shearing loads and energy were required, but the texture and the like were almost the same as those of pregelatinized starch dry powders with a crystallinity of 1% or more.

[0124] Thus, it is a surprising finding that, during shearing, whether or not the gap distance between the rigid members is varied by the force from the facing surface side of the rigid members and the degree thereof result in significantly different crystallinities of the obtained pregelatinized starch dry powder.

[0125] (3-3) Measurement of moisture content The moisture content of the pregelatinized starch dry powder (pregelatinized rice dry powder) was measured under the following conditions. An infrared moisture meter "FD-720" (manufactured by KITT) was used for the measurement. The measurement sample was set to 3 g, and the drying temperature was set to 105°C. The amount of moisture change over 30 seconds was measured, and the measurement was terminated when it reached 0.01 w / w% or less from the start of the measurement. The moisture content was calculated from the amount of moisture change.

[0126] Table 1 is a table showing the moisture content of each pregelatinized starch dry powder. In Table 1, "load" means the load of the spring used. In Table 1, "conventional method" means the result obtained using the pregelatinized rice dry powder obtained in the same manner as in the examples of Japanese Patent No. 4767128.

[0127]

Table 1

[0128] (3-4) Measurement of loss elastic modulus The pregelatinized starch dry powder (pregelatinized rice dry powder) was gelled under the following conditions, and the loss elastic modulus was measured.

[0129] (3-4-1) Preparation of rice gel For each pregelatinized starch dry powder, three times the dry basis weight of water was added, and gelation was carried out by high-speed shear stirring under the following conditions. [Conditions for high-speed shear stirring] Apparatus: "Robocoup R-5plus" (manufactured by FMI) Stirring conditions: rotation speed 1500 rpm, stirring time 3 minutes

[0130] (3-4-2) Measurement of dynamic viscoelasticity Under the following conditions, the loss elastic modulus “G” was measured at 0.01% to 100%. In order to prevent the drying of the rice gel during measurement, oil was applied to the side surface of the sample before each measurement. silicone Also, before measurement, it was held at the measurement temperature (measurement start temperature) for 5 minutes to equilibrate the temperature. [Measurement Conditions] Apparatus: “MCR301” (Anton Paar) Fixture: 25 mm parallel plate Conditions: Strain 0.01 to 100%, frequency 1 Hz, temperature 25°C

[0131] Figure 5 is a diagram showing the relationship between the loss elastic modulus and the shear strain for each obtained pregelatinized starch dry powder. In Figure 5, “conventional method” means the result obtained using the pregelatinized rice dry powder obtained in the same manner as in the examples of Japanese Patent No. 4767128. For the pregelatinized starch dry powder obtained by shear using a load of “19.58 kN / m^²” to “43.09 kN / m^²”, the maximum value at the peak that appears between a shear strain of 0.03 and 0.25 was larger than the value at a shear strain of 0.001.

[0132] Thus, it is a surprising finding that the dynamics of the loss elastic modulus of the pregelatinized starch dry powder are completely different depending on whether the gap interval between the rigid members is varied by the force from the opposing surface side of the rigid members during shear.

[0133] (3 - 5) Analysis of the viscosity profile over time The gelatinization viscosity behavior over time was analyzed under the following conditions to obtain a viscosity profile over time.<L 43 g of water was added to 7.0 g of pregelatinized starch dry powder to prepare a sample (a 14 mass% aqueous solution of pregelatinized starch dry powder). Next, using “MCR301” (Anton Paar), a temperature change was applied to each sample over 1400 seconds. The temperature program was set as follows. First, after equilibrating the temperature at 35°C, the temperature was increased by 10°C per minute to 95°C, held at that temperature for 6 minutes, and finally decreased by 10°C per minute until it reached 35°C. The paddle rotation speed was set at 160 rpm.

[0134] Table 2 is a table showing the viscosities of each sample. In Table 2, "load" means the load of the spring used. In Table 2, "initial viscosity" means the viscosity of the sample at 35°C. In Table 2, "viscosity after heating" means the viscosity of the sample immediately after heating at 95°C for 5 minutes. In Table 2, "conventional method" means the result obtained using gelatinized rice dry powder obtained in the same manner as in the examples of Japanese Patent No. 4767128. [[ID=!13]]

[0135] [[ID=!15]]

Table 2

[0136] As shown in Table 1, when shearing was performed using a spring, at 35°C, it had a viscosity in the range of 30 Pa·s or more and 500 Pa·s or less, and the viscosity immediately after heating at 95°C for 5 minutes was in the range of 300 Pa·s or more. On the other hand, in the "conventional method", although the viscosity at 35°C was high, the viscosity after heating became low, showing a completely different behavior from the gelatinized starch dry powder obtained using a spring.

[0137] Figure 6 shows the obtained viscosity profile over time. In Figure 6, "conventional method" means the result obtained using gelatinized rice dry powder obtained in the same manner as in the examples of Japanese Patent No. 4767128. As shown in Figure 6, when shearing was performed using a spring, the first peak of the viscosity profile over time ク is was much larger (more than twice) than the initial value (0 sec). Also, the first peak ク or more drop also always showed a value higher than the initial value. Note: There are some tags that seem to be duplicates or have an exclamation mark in front in the original text. I've translated them as they are but it might be a formatting or tagging error in the original.

[0138] On the other hand, when shearing was performed without using a spring, the difference between the first peak of the viscosity profile over time and the initial value was found to be less than 2.0 times. Furthermore, the first peak ク or more showed a value lower than the initial value.

[0139] (3-6) Evaluation of gelatinized starch dry powder (gelatinized rice dry powder) The gelatinized rice dry powder obtained in this example was easy to adjust in viscosity and had excellent handling characteristics. In addition, the gelatinized rice dry powder could be processed without using a binder, enabling various textures (firmness, chewiness, etc.) and was suitable for bread making and the like.

[0140] <Production of gelatinized starch dry powder (gelatinized buckwheat dry powder)> In the same manner as <Production of gelatinized starch dry powder (gelatinized rice dry powder)> above, gelatinized buckwheat dry powder was produced using buckwheat (buckwheat seeds) instead of rice. For the obtained gelatinized starch dry powder (gelatinized buckwheat dry powder), gel filtration chromatography analysis, measurement of crystallinity, measurement of moisture content, and gelation test were performed.

[0141] Table 3 is a table showing the relationship between the load of the spring used for shearing and the crystallinity of the obtained gelatinized starch dry powder (gelatinized buckwheat dry powder). In Table 3, "load" means the load of the spring used. In Table 3, "conventional method" means the result obtained using the gelatinized starch dry powder obtained in the same manner as in the examples of Japanese Patent No. 4767128.

[0142]

Table 3

[0143] Table 4 is a table showing the moisture content of each gelatinized starch dry powder. In Table 4, "load" means the load of the spring used. In Table 4, "conventional method" means the results obtained using the pregelatinized dry powder obtained in the same manner as in the examples of Japanese Patent No. 4767128. starch This refers to the results obtained using the dried powder.

[0144]

Table 4

[0145] Figure 7 is a diagram showing the relationship between the loss modulus and shear strain for the pregelatinized starch dry powder (pregelatinized buckwheat dry powder). In Figure 7, "conventional method" means the results obtained using the pregelatinized starch dry powder obtained in the same manner as in the examples of Japanese Patent No. 4767128.

[0146] The maximum value at the peak that appears between a shear strain of 0.03 and 0.25 of the pregelatinized starch dry powder was greater than the value at a shear strain of 0.001.

[0147] Figure 8 is the viscosity profile over time of the pregelatinized starch dry powder (pregelatinized buckwheat dry powder). In Figure 8, "conventional method" means the results obtained using the pregelatinized starch dry powder obtained in the same manner as in the examples of Japanese Patent No. 4767128.

[0148] The pregelatinized buckwheat dry powder obtained in this example was easy to adjust in viscosity and had excellent handling characteristics. In addition, the pregelatinized buckwheat dry powder could be processed without using a binder, enabling various textures (such as firmness and chewiness) to be achieved, and was suitable for noodle making and the like.

Claims

1. A method for producing pregelatinized starch dry powder, comprising: subjecting grains to a production apparatus equipped with a pulverizing mechanism and a temperature adjusting means, and pulverizing the grains under shearing conditions, wherein the pulverizing mechanism comprises: at least two rigid members arranged opposite to each other; and a pressing member that presses at least one of the rigid members at 15 kN / m 2 or more so that the gap interval between the rigid members varies depending on the force from the opposite surface side of the rigid members; the temperature adjusting means adjusts the temperature of the grains during the process of being sheared by the pulverizing mechanism; the rigid members are arranged so as to be able to shear and pulverize the grains supplied to the gap formed by the opposing surfaces of the rigid members; A production method.

2. Pregelatinized starch dry powder that satisfies all of the following requirements, wherein the maximum value at the peak that appears between a shear strain of 0.03 and 0.25 in the loss modulus in the gelation test is greater than the value at a shear strain of 0.

001. (Requirement 1A) In gel filtration chromatography, it has at least three peaks indicating starch. (Requirement 1B) In the at least three peaks, the first peak from the high molecular weight side has a lower intensity than the third peak from the high molecular weight side. (Requirement 1C) The crystallinity is 22.5% or less.

3. Pregelatinized starch dry powder that satisfies all of the following requirements, wherein the maximum value at the peak that appears between a shear strain of 0.03 and 0.25 in the loss modulus in the gelation test is greater than the value at a shear strain of 0.

001. (Requirement 2A) In gel filtration chromatography, it has at least three regions indicating starch. When the region from 120 minutes or more to less than 145 minutes among the three regions is defined as "A", the region from 145 minutes or more to less than 190 minutes is defined as "B", and the region from 190 minutes or more to less than 250 minutes is defined as "C", both of the following formulas (1) and (2) are satisfied. A / (A + B + C) > 0.05 Formula (1) C / (A + B + C) > 0.2 Formula (2) (Requirement 2B) The crystallinity is 22.5% or less.

4. A 14% by mass aqueous solution of the pregelatinized starch dry powder has a viscosity of 30 Pa·s or more and 500 Pa·s or less at 35°C, and the viscosity of the aqueous solution immediately after heating at 95°C for 5 minutes is 300 Pa·s or more. The pregelatinized starch dry powder according to claim 2 or 3.

5. The pregelatinized starch dry powder according to claim 2 or 3, wherein the viscosity of a 14% by mass aqueous solution of the pregelatinized starch dry powder immediately after heating at 95°C for 5 minutes is 1000 Pa·s or more.

6. The pregelatinized starch dry powder according to claim 2 or 3, having a moisture content of 12.5% by mass or less.

7. In the loss elastic modulus in the gelation test, the maximum value at the peak that appears between a shear strain of 0.03 and 0.25 is 1.30 times or more greater than the value at a shear strain of 0.

001. The pregelatinized buckwheat dry powder having a crystallinity of 18.0% or less.

8. In the loss elastic modulus in the gelation test, the maximum value at the peak that appears between a shear strain of 0.03 and 0.25 is 1.30 times or more greater than the value at a shear strain of 0.

001. The pregelatinized buckwheat dry powder having a moisture content of 12.5% by mass or less.

9. A production apparatus for pregelatinized starch dry powder, comprising a pulverizing mechanism and a temperature adjusting means, wherein the pulverizing mechanism comprises at least two rigid members arranged opposite to each other, and a pressing member that presses at least one of the rigid members at 15 kN / m2 or more so that the gap interval between the rigid members can be changed by the force from the opposite surface side of the rigid members. The temperature adjusting means adjusts the temperature of the grain during the process of being sheared by the pulverizing mechanism. The rigid members are arranged so as to be able to shear and pulverize the grains supplied to the gap formed by the opposite surfaces of the rigid members. Production apparatus.

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