Pregelatinized starch, apparatus for producing pregelatinized starch, and method for producing pregelatinized starch

Abstract

To provide a pregelatinized starch having a novel property.SOLUTION: A pregelatinized starch of the present invention meets a prescribed requirement.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pregelatinized starch, an apparatus for producing pregelatinized starch, and a method for producing pregelatinized starch. [Background technology]

[0002] Pregelatinized starch is usually obtained by adding water to starch, followed by heating and drying. On the other hand, from the viewpoint of cost reduction and the like, methods for producing pregelatinized starch without adding water have also been proposed (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4767128 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in order to meet diversifying purposes, etc., there is a need for pregelatinized starches having novel properties.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pregelatinized starch having novel properties. [Means for solving the problem]

[0006] The present inventors have investigated the shearing conditions of grains in the production of pregelatinized starch, and as a result have discovered pregelatinized starch with new properties, thereby completing the present invention. Specifically, the present invention provides the following.

[0007] (1) Pregelatinized starch that meets all of the following requirements: (Requirement 1A) In gel filtration chromatography, it has at least three peaks indicating amylopectin. (Requirement 1B) Of the at least three peaks, the first peak from the high molecular weight side has a higher intensity than the third peak from the high molecular weight side. (Requirement 1C) The crystallinity is 22.5% or less.

[0008] (2) Pregelatinized starch that meets all of the following requirements: (Requirement 2A) In gel filtration chromatography, it has at least three peaks indicating amylopectin. (Requirement 2B) The crystallinity is between 1% and 12%. (Requirement 2C) The loss modulus in the gelation test is less than 10% of the shear strain. -4 Within the range of 100 or more, the value increases after 1 to 3 days.

[0009] (3) The pregelatinized starch according to (1) or (2), in which the first peak exhibits an intensity that is 2.0 times or more greater than the initial value in a time-dependent viscosity profile obtained in the following viscosity test. (Viscosity test) The temperature is changed at a constant rate from room temperature to 95° C. and back to room temperature over a period of 1400 seconds.

[0010] (4) An apparatus for producing pregelatinized starch comprising a grinding mechanism and a temperature adjusting means, The crushing mechanism includes: At least two rigid members arranged opposite 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 grain during the process of being sheared by the grinding mechanism, The rigid members are arranged so as to be able to shear and crush grains supplied into a gap formed by the opposing surfaces of the rigid members. Manufacturing equipment.

[0011] (5) A method for producing pregelatinized starch, comprising the steps of: The method includes subjecting grains to a manufacturing device having a grinding mechanism and a temperature control means and grinding the grains under shear conditions; The crushing mechanism includes: At least two rigid members arranged opposite 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 grain during the process of being sheared by the grinding mechanism, The rigid members are arranged so as to be able to shear and crush grains supplied into a gap formed by the opposing surfaces of the rigid members. Manufacturing method. Effect of the Invention

[0012] According to the present invention, there is provided a pregelatinized starch having novel properties. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a schematic diagram of a mortar-type grinding machine used in the examples. [Diagram 2] FIG. 1 shows the results of gel filtration chromatography analysis in an example. [Diagram 3] FIG. 1 shows the results of gel filtration chromatography analysis in an example. [Figure 4] FIG. 1 is a diagram showing the crystallinity of pregelatinized starches prepared in the Examples. [Diagram 5] FIG. 1 shows the dynamics of the loss modulus of pregelatinized starch prepared in the Examples. [Figure 6] FIG. 2 is a diagram showing the results of an analysis of a viscosity profile over time in an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described in detail, but the present invention is not particularly limited thereto.

[0015] <gelatinized starch> The pregelatinized starch of the present invention includes the following two embodiments. (1) Pregelatinized starch according to the first aspect A pregelatinized starch that meets all of the following requirements. (Requirement 1A) In gel filtration chromatography, it has at least three peaks indicating amylopectin. (Requirement 1B) Of the at least three peaks, the first peak from the high molecular weight side has a higher intensity than the third peak from the high molecular weight side. (Requirement 1C) The crystallinity is 22.5% or less. (2) Pregelatinized starch according to the second aspect A pregelatinized starch that meets all of the following requirements. (Requirement 2A) In gel filtration chromatography, it has at least three peaks indicating amylopectin. (Requirement 2B) The crystallinity is between 1% and 12%. (Requirement 2C) The loss modulus in the gelation test is less than 10% of the shear strain. -4 Within the range of 100 or more, the value increases after 1 to 3 days.

[0016] The above-mentioned pregelatinized starch has a combination of properties (i.e., the above-mentioned requirements) different from those of existing pregelatinized starches. The present inventors have created such a novel pregelatinized starch by employing specific shear conditions (described below).

[0017] In the present invention, the term "gelatinized starch" includes grains (such as rice, wheat, buckwheat, and red beans) whose main component is starch that have been gelatinized (gelatinized and decrystallized).

[0018] The gelatinized starch according to each embodiment will be described below.

[0019] (Pregelatinized Starch According to the First Aspect) The pregelatinized starch according to the first aspect (hereinafter also referred to as "first pregelatinized starch") satisfies all of requirements 1A to 1C. However, the first pregelatinized starch may or may not further satisfy requirements 2B and / or 2C in addition to requirements 1A to 1C.

[0020] [Regarding Requirement 1A] The first pregelatinized starch has at least three peaks indicative of amylopectin in its gel filtration chromatography.

[0021] In the present invention, "gel filtration chromatography" is performed by the method shown in the Examples.

[0022] In the present invention, the "peak indicating amylopectin" can be identified by the following method. Each "peak" is based on the part of the graph from the lowest value to the highest value to the next lowest value. However, for example, the third and fourth peaks from the high molecular weight side may show a shoulder on the graph. In that case, the boundary between the peaks is, for example, the point where the downward curve becomes gentle or the point where the upward curve becomes gentle.

[0023] The first pregelatinized starch has peaks representing amylopectin, preferably at least 4, more preferably at least 3. The upper limit of the number of peaks representing amylopectin is not particularly limited, but is usually 4 or less. In the present invention, the first, second, third, . . . nth peaks are distinguished by retention time intervals (for example, 120 to 150 minutes, 150 to 190 minutes, 190 to 230 minutes, and 230 to 260 minutes).

[0024] The gel filtration chromatography of the first pregelatinized starch may have, but is not limited to, the following four peaks. Retention time 120-150 min: First peak from high molecular weight side Retention time 150-190 min: Second peak from the high molecular weight side Retention time 190-230 min: Third peak from the high molecular weight side Retention time 230-260 min: Fourth peak from the high molecular weight side

[0025] The first pregelatinized starch can have a ratio of each peak area to the total area of ​​the above four peaks that satisfies the following range. First peak from high molecular weight side: 20-40% Second peak from high molecular weight side: 25-35% The third peak from the high molecular weight side: 15-40% The fourth peak from the high molecular weight side: 5-20%

[0026] [Regarding Requirement 1B] In the at least three peaks representing amylopectin of the first pregelatinized starch, the first peak from the high molecular weight side has a higher intensity than the third peak from the high molecular weight side.

[0027] In the present invention, the "nth peak from the high molecular weight side" means the nth peak counted from the peak with the shortest chromatographic retention time. For example, "the first peak from the high molecular weight side" means the peak observed with the shortest retention time.

[0028] In the present invention, "the first peak from the high molecular weight side has a higher 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 higher than the value of the third peak from the high molecular weight side. This is presumably the result of a moderate proportion of high molecular weight amylopectin being converted to a low molecular weight form by the shear force described below.

[0029] As a result of the inventors' investigations, it was found that, as shown in a comparative example described later ( FIG. 2(B) ), in the case of a pregelatinized starch obtained using the production apparatus of Patent Document 1 that does not have a pressing member, the first peak from the high molecular weight side is lower than the third peak from the high molecular weight side.

[0030] In the first pregelatinized starch, the first peak from the high molecular weight side has an intensity preferably 1.1 or more times, more preferably 1.5 to 3 times, higher than the intensity of the third peak from the high molecular weight side.

[0031] [Regarding Requirement 1C] The first pregelatinized starch has a degree of crystallinity of 22.5% or less, that is, the first pregelatinized starch has a high proportion of amorphous portions.

[0032] The lower limit of the crystallinity of the first pregelatinized starch is preferably 1% or more, more preferably 2% or more, even more preferably 4% or more, even more preferably 7% or more, and even more preferably 12% or more.

[0033] The upper limit of the crystallinity of the first pregelatinized starch is preferably 20.0% or less, more preferably 17% or less, or 14% or less.

[0034] In the present invention, the "crystallinity" is specified by the method shown in the Examples.

[0035] (Pregelatinized Starch According to the Second Aspect) The pregelatinized starch according to the second embodiment (hereinafter also referred to as "second pregelatinized starch") satisfies all of requirements 2A to 2C. However, the second pregelatinized starch may or may not further satisfy requirement 1B in addition to requirements 2A to 2C.

[0036] Hereinafter, explanation of requirements that overlap with those for the first pregelatinized starch will be omitted as appropriate.

[0037] [About Requirement 2A] In order to satisfy requirement 2A, the same configuration as that in requirement 1A of the first pregelatinized starch can be adopted.

[0038] The gel filtration chromatography of the second pregelatinized starch may have, but is not limited to, the following four peaks. Retention time 120-150 min: First peak from high molecular weight side Retention time 150-190 min: Second peak from the high molecular weight side Retention time 190-230 min: Third peak from the high molecular weight side Retention time 230-260 min: Fourth peak from the high molecular weight side

[0039] The second pregelatinized starch can have a ratio of each peak area to the total area of ​​the above four peaks that satisfies the following range. The first peak from the high molecular weight side First peak from high molecular weight side: 3-40% Second peak from high molecular weight side: 20-35% The third peak from the high molecular weight side: 20-60% The fourth peak from the high molecular weight side: 10-20%

[0040] [About Requirement 2B] The second pregelatinized starch has a degree of crystallinity of 1% or more and 12% or less. In other words, the second pregelatinized starch has an appropriately high proportion of amorphous parts. Pregelatinized starch with a degree of crystallinity in this range is difficult to obtain using the production apparatus of Patent Document 1, which does not have a pressing member.

[0041] The lower limit of the crystallinity of the second pregelatinized starch is preferably 1.2% or more, preferably 1.5% or more, preferably 2% or more, more preferably 4% or more, even more preferably 7% or more, and even more preferably 9% or more. Crystallinity of pregelatinized starch: Setting the crystallinity of pregelatinized starch to less than 1% not only requires costs associated with the operation of the equipment, but also has almost no effect on the properties (texture, etc.) of pregelatinized starch that satisfies requirements 2A and 2C. In other words, pregelatinized starch that satisfies requirement 2B in combination with requirements 2A and 2C can be produced at reduced cost and has good properties.

[0042] The upper limit of the crystallinity of the second pregelatinized starch is preferably 10% or less, more preferably 11% or less.

[0043] [About Requirement 2C] The second type of pregelatinized starch exhibited a loss modulus of 10% at shear strain in the gelation test. -4 Within the range of 100 or more, the value increases after 1 to 3 days.

[0044] It is common knowledge that the loss modulus of gelatinized starch decreases over time in a gelation test. However, contrary to this common knowledge, the second pregelatinized starch exhibits an increase in loss modulus over time. Therefore, pregelatinized starch satisfying requirement 2C is novel.

[0045] In the present invention, "the loss modulus increases from 1 day to 3 days" means that the loss modulus 3 days after the start of the gelation test is higher than the loss modulus 1 day after the start of the gelation test. More preferred embodiments of the present invention include those in which the loss modulus three days after the start of the gelation test is higher than the loss modulus two days after the start of the gelation test, and the loss modulus two days after the start of the gelation test is higher than the loss modulus one day after the start of the gelation test.

[0046] In the present invention, the "gelation test" is carried out by the method shown in the Examples.

[0047] [Other requirements] Other requirements for the first and second pregelatinized starches are not particularly limited, but they may have the following viscosity characteristics.

[0048] In a preferred embodiment of the present invention, the pregelatinized starch has a first peak that exhibits an intensity that is 2.0 times or more greater than the initial value in a time-dependent viscosity profile obtained in the following viscosity test. (Viscosity test) The temperature is changed at a constant rate from room temperature to 95° C. and back to room temperature over a period of 1400 seconds.

[0049] In the present invention, the term "viscosity profile over time" refers to data showing a change in viscosity accompanying a change in temperature over time. More specifically, the viscosity profile over time is determined by the method shown in the Examples.

[0050] In the present invention, the "first peak in the viscosity profile over time" means the peak that first appears as the temperature changes over time.

[0051] In the present invention, the "initial value of the viscosity profile over time" means the value at the start of the analysis of the viscosity profile over time.

[0052] As a result of studies by the present inventors, it was found that in the gelatinized starch obtained using the production apparatus of Patent Document 1, which does not have a pressing member, the first peak in the viscosity profile over time is equal to or lower than the initial value, and furthermore, after the first peak (approximately 400 sec), a value lower than the initial value is observed. Therefore, the first pregelatinized starch having the above viscosity characteristics is novel.

[0053] In a preferred embodiment of the present invention, the viscosity profile over time of the first pregelatinized starch exhibits values ​​that are always higher than the initial value even after the first peak.

[0054] In the first pregelatinized starch, the first peak in the viscosity profile over time has a high intensity that is preferably 1.2 times or more, and more preferably 1.5 to 10 times, higher than the initial value.

[0055] (Application) The applications of the pregelatinized starch of the present invention are not particularly limited, and the pregelatinized starch can be used for any applications, such as the same applications as conventionally known pregelatinized starches (foods, medicines, etc.).

[0056] <Method of producing pregelatinized starch> The pregelatinized starch of the present invention can be produced by any apparatus used for pregelatinizing grains.

[0057] In the process for producing the gelatinized starch of the present invention, water may or may not be added to the grains. From the viewpoint of easily obtaining pregelatinized starch, it is preferable that the process for producing the pregelatinized starch of the present invention does not include a step of adding water to grains.

[0058] (Preferred manufacturing equipment) A known method for producing pregelatinized starch is to fix two mortars to an axis and grind and pulverize grains placed between them by rotating the mortars (for example, Japanese Patent No. 4767128). However, the present inventors have found that when pulverization is carried out under shear conditions with the gap distance between dies being variable, a pregelatinized starch having novel properties, that is, the pregelatinized starch of the present invention, is easily obtained.

[0059] Specifically, an apparatus that can easily produce the gelatinized starch of the present invention is an apparatus for producing gelatinized starch that is equipped with a predetermined grinding mechanism and temperature adjustment means. In the manufacturing apparatus, the crushing mechanism has at least two rigid members arranged opposite each other, and a pressing member that presses at least one of the rigid members so that the gap distance between the rigid members is variable by a force from the opposing surface side of the rigid members. The temperature adjusting means adjusts the temperature of the grains as they are being sheared by the grinding mechanism. The rigid members are positioned so as to be able to shear and crush grains fed into a gap formed by opposing surfaces of the rigid members.

[0060] In a preferred embodiment of the present invention, the pregelatinized starch is obtained by subjecting grains to the above-mentioned production apparatus and pulverizing them under shear conditions.

[0061] [Crushing mechanism] The crushing mechanism has at least a rigid member and a pressing member.

[0062] In the present invention, the term "rigid members" refers to at least two members arranged to face each other, which shear and crush grains fed therebetween. The gap between the rigid members may be preferably 0 to 3 to 0 mm, and more preferably 0 to 1 mm.

[0063] The rigid member may be of any shape, material, etc. employed for mills and rollers in conventionally known devices.

[0064] In the present invention, the "pressing member" is a member that is disposed on the surface side opposite to the opposing surfaces of two rigid members and that changes the gap distance between the rigid members. However, the gap distance varies depending on the force generated from the opposing surface of the rigid member (for example, the force generated by the grinding of grains, etc.).

[0065] The biasing member may be any biasing means, such as a spring.

[0066] When the first pregelatinized starch is obtained, the load of the biasing means is preferably 100 N or more, more preferably 160 N or more, from the viewpoint of sufficiently shearing the grains and facilitating the production of pregelatinized starch that satisfies (requirement 1C). The load of the biasing means is preferably 300 N or less, preferably 250 N or less, preferably 220 N or less, preferably 150 N or less, and more preferably 136 N or less, from the viewpoint of sufficiently varying the gap distance between the rigid members and making it easier to obtain pregelatinized starch that satisfies (Requirement 1B).

[0067] When the second pregelatinized starch is obtained, the load of the biasing means is preferably 90 N or more, more preferably 100 N or more, even more preferably 130 N or more, and more preferably 200 N or more, from the viewpoint of sufficiently shearing the grains and facilitating the production of pregelatinized starch that satisfies (requirement 2B). The load of the biasing means is preferably 300 N or less, preferably 250 N or less, more preferably 220 N or less, and even more preferably 200 N or less, from the viewpoint of sufficiently varying the gap distance between the rigid members and making it easier to obtain pregelatinized starch that satisfies (Requirement 2C).

[0068] The number of pressing members is not particularly limited, and they may be arranged so as to press both of the two rigid members, or so as to press only one of them.

[0069] The conditions for crushing the grains by the crushing mechanism are not particularly limited, but the rigid member is preferably crushed at a shear rate of 90 to 600 sec -1 , more preferably 280 to 600 seconds -1 It may be rotated so that

[0070] [Temperature adjustment means] The temperature adjusting means adjusts the temperature of the grains as they are being sheared by the grinding mechanism.

[0071] The temperature adjusting means may be a conventionally known heater. The shearing of the grains can be carried out, for example, at a temperature of preferably 80°C or higher, more preferably 100 to 200°C.

[0072] Other configurations of the manufacturing apparatus may be conventionally known configurations (grain supply port, grain removal port, etc.) depending on the purpose, etc. EXAMPLES

[0073] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0074] <Preparation of pregelatinized starch> The grains were pulverized using a mortar-type pulverizer to produce gelatinized starch in the following manner.

[0075] (1) Preparation of the mortar grinder A small temperature-controlled mortar-type grinder was prepared. This crusher has a structure similar to that of the device shown in Fig. 1 of Japanese Patent No. 4767128. Specifically, it is equipped with a crushing mechanism having an upper mill and a lower mill (corresponding to rigid members) arranged opposite to each other, a temperature adjustment means for adjusting the temperature of the upper mill, a grain supply port, a grain removal port, etc. In this grinding machine, grains are fed into a grain supply port into the gap between the upper and lower mills and are ground by the action of the upper and lower mills. The ground product (gelatinized starch) can be collected from a grain discharge port.

[0076] The upper and lower mills of this grinding machine are fixed in position, and the lower mill rotates horizontally relative to the surface facing the upper mill, applying shear force to the grains. In this example, a spring (corresponding to a pressing member) was provided under the lower mill, and the mill was modified so that it could also move in a direction perpendicular to the surface facing the upper mill.

[0077] The springs used had a load in the range of 50 N to 220 N. The higher the load value, the more difficult it is to change the gap between the upper and lower mills.

[0078] A schematic diagram of the mortar-type grinding machine used in this example is shown in Figure 1.

[0079] (2) Shearing of grains The grains used were corn-derived amylopectin and "Haenuki" rice produced in Yamagata Prefecture in 2020. The grains were fed to a mortar-type grinder, where they were sheared and crushed in the gap (approximately 0 mm) between the upper and lower mortars. In this example, no water was added to the grains. The resulting pulverized product corresponds to pregelatinized starch. The shear temperature was set to 120°C. The shear rate was 500 sec -1 was set to.

[0080] (3) Analysis of pregelatinized starch The obtained pregelatinized starch was subjected to gel filtration chromatography analysis, crystallinity measurement, and gelation test.

[0081] (3-1) Gel filtration chromatography analysis To the gelatinized starch (20 mg), 1.6 mL of distilled water was added and suspended using a homogenizer. After that, 0.4 mL of 5 M NaOH was added and stirred, followed by gelatinization at 37° C. for 30 minutes. Next, 2 mL each of distilled water and eluent (0.05 M NaOH / 0.2% NaCl) was added, mixed, and filtered through a 5 μm filter to prepare 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 performed under the following conditions: eluent 0.05 M NaOH / 0.2% NaCl, flow rate 1 mL / min. An IR detector was used for detection, and the detection values ​​from 100 to 260 minutes were used.

[0082] The results of the gel filtration chromatography analysis are shown in FIGS.

[0083] In FIG. 2, (A) shows the results when a 136N spring was used, and (B) shows the results when a 160N spring was used. When a "136N" spring was used, the gap between the upper and lower mills was variable depending on the force from the opposing surface of the rigid member (the lower mill in this example). On the other hand, when a "160N" spring was used, the vertical position of the rigid member (the lower mill in this example) was fixed, and the gap between the upper and lower mills was fixed.

[0084] As shown in FIG. 2(A), when a spring load of "136 N" was used, at least three peaks indicating amylopectin were observed (retention time: approximately 120 min, approximately 140 min, approximately 160 min, approximately 220 min, approximately 240 min). In addition, the first peak from the high molecular weight side (Retention time: about 120 min) had a higher intensity than the third peak from the high molecular weight side (Retention time: about 160 min). Therefore, when a spring with a load of "136 N" was used, pregelatinized starches satisfying (requirement 1A), (requirement 1B), and (requirement 2A), respectively, were obtained.

[0085] In contrast, as shown in Figure 2(B), even when a spring load of "160 N" was used, at least three peaks indicating amylopectin were observed (retention time: approximately 120 min, approximately 140 min, approximately 160 min, approximately 220 min, approximately 240 min). However, the first peak from the high molecular weight side (Retention time: about 120 min) had a lower intensity than the third peak from the high molecular weight side (Retention time: about 160 min). Therefore, when a spring with a load of "160 N" was used, a pregelatinized starch was obtained that satisfied (Requirement 1A) and (Requirement 2A) but did not satisfy (Requirement 1B).

[0086] Although data is not shown, all of the gelatinized starches obtained from the production apparatus of Patent Document 1, which does not have a pressing member, showed peaks having the same characteristics as those in FIG. 2(B).

[0087] FIG. 3 shows the proportion of each peak area in the total area of ​​four peaks in gel filtration chromatography of pregelatinized starch obtained using a control (no spring) or each spring of 50 to 220 N. The "conventional method" refers to the result of gel filtration chromatography of pregelatinized starch obtained without a spring and by gelatinization at 120°C.

[0088] Thus, it is a surprising finding that the gel filtration chromatography of the obtained pregelatinized starch is completely different depending on whether or not the gap distance between the rigid members is changed by the force from the opposing surface side of the rigid members during shearing.

[0089] (3-2) Measurement of crystallinity Based on the results of wide-angle X-ray diffraction measurements, the peaks were separated into amorphous scattering and crystalline reflections. The integral value of the peak due to amorphous scattering obtained is called "S a ” and the integral value of the peak due to crystal reflection is “S c " and the crystallinity of the pregelatinized starch was calculated based on the following formula. Crystallinity (%)=(Sc / (Sc+Sa))×100

[0090] (Wide-angle X-ray diffraction measurement conditions) Measuring equipment: "RINT-RAPID", manufactured by Rigaku Scan speed: 4° / min Measurement angle: 5~35° Tube voltage: 40kV Tube current: 30mA

[0091] Figure 4 plots the relationship between the load of the spring used for shearing and the crystallinity of the resulting pregelatinized starch. In Figure 4, the results for a load of "0" are those for shearing without using a spring.

[0092] As shown in Figure 4, the crystallinity was approximately 10% for the load of 136N. Therefore, when a spring with a load of 136 N was used, as described above, a pregelatinized starch was obtained that satisfied not only (Requirement 1A), (Requirement 1B), and (Requirement 2A), but also (Requirement 1C) and (Requirement 2B). Furthermore, when a spring with a load of 60 N or more was used, it was easier to obtain pregelatinized starch that satisfied (requirement 1C) and (requirement 2B).

[0093] Furthermore, as shown in FIG. 4, at loads of "200N," "220N," "250N," and "290N," the crystallinity was approximately 2%, approximately 1.2%, approximately 1.5%, and approximately 1.5%, respectively, all of which satisfied (Requirement 1C) and (Requirement 2B).

[0094] In contrast, when a spring with a load of 50 N or less was used, not only did it not satisfy (Requirement 1C) and (Requirement 2B), but also the amorphization was insufficient, resulting in a pregelatinized starch with inferior performance. Although not shown, these pregelatinized starches were either pregelatinized starches with a degree of crystallinity of more than 12% (pregelatinized starches with low amorphousness) or pregelatinized starches with a degree of crystallinity of less than 1% (pregelatinized starches with excessive amorphousness). In addition, although a very strong shear load and energy were required to obtain pregelatinized starches with a degree of crystallinity of less than 1%, the texture and the like were almost the same as those of pregelatinized starches with a degree of crystallinity of 1% or more.

[0095] Thus, it is a surprising finding that the degree of crystallinity of the resulting pregelatinized starch completely differs depending on whether or not the gap distance between the rigid members is changed by the force from the opposing surfaces of the rigid members during shearing, and depending on the extent to which this is done.

[0096] (3-3) Measurement of loss modulus The gelatinized starch was gelled under the following conditions, and the loss modulus was measured.

[0097] (3-3-1) Preparation of rice gel Water was added in an amount three times the dry basis weight of each pregelatinized starch, and gelatinization was carried out by high-speed shear stirring under the following conditions. The obtained samples (rice gel) were sealed in polyethylene bags to prevent contact with air and stored in a refrigerator (4°C to 10°C). The refrigerated storage was continued for three days, and rice gel samples were taken on the 0th, 1st, 2nd, and 3rd days, and the loss modulus was measured using the method described below. [High-speed shear mixing conditions] Equipment: "Robocoupe R-5plus" (FMI) Mixing conditions: Rotation speed 1500 rpm, mixing time 3 minutes

[0098] (3-3-2) Measurement of dynamic viscoelasticity The loss modulus “G”” was measured from 0.01% to 100% under the following conditions. In order to prevent the rice gel from drying out during the measurement, oil was applied to the side of the sample before each measurement. In addition, the sample was kept at the measurement temperature (measurement start temperature) for 5 minutes before the measurement to allow the temperature to equilibrate. [Measurement conditions] Equipment: "MCR301" (Anton Paar) Fixture: 25mm parallel plate Conditions: Strain 0.01-100%, Frequency 1Hz, Temperature 25℃

[0099] FIG. 5 is a graph showing the relationship between the loss modulus and the shear strain for each of the obtained pregelatinized starches. As shown in FIG. 5, the loss modulus after gelatinization of all the pregelatinized starches obtained by shearing using a spring of 136 to 220 N increased over time. These gelatinized starches have a loss modulus of 10% shear strain in the gelation test. -4 In the range of 100 or more, the levels increased from 1 day to 3 days after the start of the experiment. Therefore, when shearing was performed using a spring of 136 to 220 N, a pregelatinized starch satisfying (requirement 2C) was obtained.

[0100] In contrast, the loss modulus after gelatinization decreased over time for the pregelatinized starch obtained by shearing without using a spring (corresponding to the pregelatinized starch obtained using the production apparatus of Patent Document 1) and the pregelatinized starch obtained by shearing with a 100 N spring.

[0101] Thus, it is a surprising finding that the behavior of the loss modulus of pregelatinized starch is completely different depending on whether the gap distance between the rigid members is changed by a force from the opposing surface side of the rigid members during shearing.

[0102] (3-4) Analysis of viscosity profile over time The gelatinization viscosity behavior over time was analyzed under the following conditions, and a viscosity profile over time was obtained. A sample was prepared by adding 25 g of water to pregelatinized starch (3.5 g). Next, using "MCR301" (Anton Paar), a temperature change was applied to each sample over a period of 1400 seconds. The temperature program was set as follows: First, the temperature was equilibrated at 35°C, then the temperature was raised by 10°C per minute to 95°C, the temperature was maintained for 6 minutes, and finally the temperature was lowered by 10°C per minute to 35°C. The paddle rotation speed was set to 160 rpm.

[0103] FIG. 6 shows the resulting viscosity profile over time. As shown in Figure 6, when shearing was performed using a spring, the first peak (at about 400 sec) in the time-dependent viscosity profile was much larger (more than twice as large) than the initial value (at 0 sec). In addition, even after the first peak (at about 400 sec), the viscosity always showed values ​​higher than the initial value.

[0104] In contrast, when shearing was performed without using a spring, the difference between the first peak of the time-dependent viscosity profile and the initial value was less than 2.0 times. Furthermore, values ​​lower than the initial value were observed after the first peak (approximately 400 seconds).

Claims

1. A pregelatinized starch that meets all of the following requirements. (Requirement 1A) In gel filtration chromatography, it has at least three peaks indicating amylopectin. (Requirement 1B) Of the at least three peaks, the first peak from the high molecular weight side has a higher intensity than the third peak from the high molecular weight side. (Requirement 1C) The crystallinity is 22.5% or less.

2. A pregelatinized starch that meets all of the following requirements. (Requirement 2A) In gel filtration chromatography, it has at least three peaks indicating amylopectin. (Requirement 2B) The crystallinity is 1% or more and 12% or less. (Requirement 2C) The loss modulus in the gelation test is less than or equal to a shear strain of 10 －４ In the range of 100 or more, the value increases after 1 to 3 days.

3. 3. The pregelatinized starch according to claim 1 or 2, wherein in a time-dependent viscosity profile obtained in the following viscosity test, a first peak exhibits an intensity that is 2.0 times or more higher than the initial value. (Viscosity Test) The temperature is changed at a constant rate from room temperature to 95° C. and back to room temperature over a period of 1400 seconds.

4. An apparatus for producing gelatinized starch comprising a grinding mechanism and a temperature adjusting means, The crushing mechanism includes: At least two rigid members arranged opposite 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 grain during the process of being sheared by the grinding mechanism, The rigid members are arranged so as to be able to shear and crush grains supplied into a gap formed by the opposing surfaces of the rigid members. Manufacturing equipment.

5. A method for producing pregelatinized starch, comprising the steps of: The method includes subjecting grains to a manufacturing device having a grinding mechanism and a temperature control means and grinding the grains under shear conditions; The crushing mechanism includes: At least two rigid members arranged opposite 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 grain during the process of being sheared by the grinding mechanism, The rigid members are arranged so as to be able to shear and crush grains supplied into a gap formed by the opposing surfaces of the rigid members. Manufacturing method.

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