JPH08143601A - Modified starch and its production - Google Patents

Abstract

PURPOSE: To obtain modified starch specifically modified in transformation of the specific surface of starch particles by an action of a mechanical energy which has not been tried in a usual starch modifying technique. CONSTITUTION: This method for producing modified starch is to make starch particles flat by one or more mechanical energies selected from a compressive force, an impact force, a grinding force and a shearing force without breaking the particles or deform into fine particles by crushing flat deformed starch particles by one or more mechanical energies to obtain the modified starch. The specific surface of the modified starch is more than 2.5 times as large as that of unmodified starch.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the powder characteristics of starch particles, and relates to the phenomenon that has a great influence on the physicochemical properties of starch particles. In particular, the specific surface area of starch particles is significantly changed by mechanical energy. And a modified starch and an industrial production method thereof.

BACKGROUND OF THE INVENTION Starch precipitates without dissolving in cold water.
It is a white fine particle of 100 micrometers (μm). Starch particles have characteristics peculiar to shape, particle size, and surface pattern, but since the particles are small and the particle size distribution is narrow, there are many applications in which the peculiar properties as powder are used as they are. For example, starch is often used in mold release agents for casting, rubber industry, etc., as excipients for medicines, foods, cosmetics, coating agents for photosensitive paper, etc. due to the fact that starch is particles. On the other hand, starch is
Unlike similar cellulose, it is composed of two components, amylose and amylopectin, and these two components form regular microcrystals to form starch particles. The regularity of the microcrystals scattered in the particles appears in the X-ray diffraction pattern, but the crystallinity differs from about 25% to 40% depending on the plant species. When these starch particles are heated with water, when they reach a certain temperature, they start to swell and the X-ray diffraction pattern disappears, and eventually the particles start to break down, elute from the low molecular weight amylose and continue heating, The particles disappear and become a uniform solution, so-called aqueous colloid. Viscoelasticity, adhesiveness, tackiness, water retention as this aqueous colloid,
Its gelling property, dry film property and the like are widely used in foods, adhesives, papermaking or textiles, medicines and the like. However, natural starch requires heating for swelling and dissolution, for example, the low-temperature stability of the aqueous colloid is poor, and aging causes the viscosity, water retention, and transparency to be lost. It has polymer characteristics such as poor chemical resistance. Therefore, for the purpose of improving the above-mentioned respective drawbacks, many modified starches have been developed in which starch is chemically, physically, or enzymatically modified. Chemically modified starches that have been chemically modified by decomposition include dextrin by roasting, acid-immersed starches that use hydrochloric acid, etc., and oxidized starch that uses sodium hypochlorite, etc. Cross-linked starch using, etc.
There are starch esters using acetic acid and the like, starch ethers using monochloroacetic acid and the like, and grafted starch using acrylonitrile and the like. Examples of the physically modified modified starch include water, α-starch using heat, and heat-moisture treated starch. Dextrin that uses α-amylase for the enzymatically modified modified starch,
There is amylose using isoamylase and the like. These modified starches have various products by combining two or more modification methods or by changing the kind and the substitution degree of the substituents of the starch derivative. The skeleton of the improvement of this modified starch was how to control the microcrystalline structure fixed by strong hydrogen bonds between the molecular chains interspersed within the particles during the starch synthesis process, according to the purpose. For general methods of producing modified starches, there are detailed explanations in basic books (for example, Starch Science Handbook, Asakura Shoten, No. 8, 1987). Among them, for example, α-starch, which is a typical modified starch, is obtained by immediately drying a paste solution in which the microcrystalline structure of starch is destroyed, and has a property of swelling in cold water. Further, for example, Japanese Patent Application Laid-Open No. 4-130102 discloses that a wet heat treatment by a reduced pressure / pressure heating method suppresses swelling and dissolution during heating, and a wet heat treated starch having almost no viscosity is obtained. However, this is because amylose in starch moves inside the particles due to heat treatment with moisture,
It is presumed that it binds to the terminal molecular chain of amylopectin and strengthens the microcrystalline structure like crosslinked starch. As described above, as a starch modification technique, the starch is water,
The method is mainly a method of physically, chemically, and enzymatically denaturing by using heat, chemicals, and enzymes, and other methods such as mechanical energy as in the present invention have a great influence on the physicochemical properties of starch. At present, the phenomenon of imparting, in particular, the modification technique for significantly increasing the specific surface area of starch particles has not been noticed and has not been studied.

SUMMARY OF THE INVENTION The present invention was developed in view of the above-mentioned conventional circumstances, and is keen to obtain a fine (fine) starch that exceeds the conventional frame in the advanced use of starch. As a result of research, there is provided a modified starch and a method for producing the same, in which a change in the specific surface area of starch particles is remarkably caused by the action of mechanical energy, which has hardly been studied as a conventional starch modification technique. That is the purpose.

[Means for Solving the Problems] Starch is characterized by its size and shape depending on the plant species. For example, the powder characteristics of corn starch, which is a typical starch, have a polygonal shape and a particle size of 3 to 35 μm, but its specific surface area was measured by the BET method using a mixed gas of nitrogen and helium. However, it was 1.0 m ² / g. The powder characteristics of potato starch are egg-shaped single grain and particle size of 10 to 90 micrometer (μm), but its specific surface area was measured by BET method to be 0.6 m ² / g. there were. Starch as a powder is an aggregate of a large number of solid fine particles, and generally, the properties peculiar to the powder include a property that appears when a solid becomes fine and a property as a particle aggregate. When the solid is miniaturized, volume effect and surface effect appear, and the property as a particle aggregate is that each powder particle has an appropriate binding force,
Because it has an attractive force. Starch used in the present invention, corn starch, high amylose corn starch, waxy corn starch, sorghum starch, potato starch, sweet potato starch, tapioca starch, sago starch,
Bean starch, wheat starch, barley starch, rice starch, kudzu starch, potato starch, canna starch, arrow root starch or cross-linked starch,
One or two or more selected from heat-moisture treated starch. INDUSTRIAL APPLICABILITY According to the present invention, a certain mechanical energy is applied to starch as a powder to induce a phenomenon that greatly affects the physicochemical properties of starch particles, particularly an increase in the specific surface area of starch particles. Here, as the mechanical energy, there are various types such as compression which is a crushing force, impact which is a tapping force, grinding which is a crushing force, shearing which is a chopping force, and in particular, the present invention uses a starch particle layer. The mechanical energy of any one of compression force, impact force, grinding force, and shearing force or two or more types of mechanical energy is applied to each formed particle. Here, milling refers to a phenomenon in which fine powder is generated from the surface of the particles due to friction between the powders, and the friction effect due to shearing under a compressed state is also known. As a particulate material processing apparatus for processing starch particles used in the present invention, for example, as disclosed in Japanese Patent Laid-Open No. 6-79192, a main shaft that rotates around a container is erected, and a plurality of main shafts are installed on the main shaft. The sub-shaft is circumferentially supported with a space, and a plurality of ring-shaped members are installed on the sub-shaft with a sufficient space between the sub-shaft and the sub-shaft. A particulate material processing device that is in contact with
The container rotates, and crushing chips having a smaller radius of curvature than the container are fixed at a certain distance to the inner wall of the container. Particles are compressed by the centrifugal force caused by the rotation of the container while being compressed into the inner wall of the container. A particulate material processing device adapted to be pushed into a portion, that is, a device such as an angmill for grinding the powder pressed against the inner wall of the rotating container while compressing it with a head of an arm that is stationary or slowly rotating at the center. Applicable. In addition, those classified into a shear friction type mill, a compression grinding type mill, a high speed shear type mixer and the like can be used. These processing apparatuses are classified into a dry type, which performs processing in the atmosphere or a special gas, and a wet type, which performs processing in a liquid. Also, there are three types of processing apparatuses: a batch type, an open circuit, and a closed circuit. The present invention can be implemented under any setting condition. The present invention provides a certain mechanical energy to starch particles, whereby the starch particles are deformed into a flat shape, or the starch particles changed into a flat shape are deformed into fine particles,
In particular, it is characterized in that the specific surface area of starch particles can be remarkably increased. Generally, when a solid is subdivided, the specific surface area, which is the surface area per unit mass, increases, which is an established finding, but when given specific mechanical energy to starch particles as in the present invention, The finely divided starch particles cause an unknown phenomenon that cannot be estimated from the average particle size. That is, it is considered that the specific surface area of the starch particles is remarkably increased because the new surface of the starch particles is not formed by simply subdividing the starch particles but by a mechanism different from the existing knowledge. The present invention is constructed on the basis of the above-mentioned novel knowledge that has never been known or predicted at all.

EXAMPLES Examples of the present invention will be described in detail below. However, the present invention is not limited to this embodiment. [Example 1] Preparation of modified corn starch The corn starch was modified by using an ultrafine pulverizer Micros (manufactured by Nara Machinery Co., Ltd.) for the purpose of pulverization as the particulate material treatment device. This processing device is composed of a casing, a main shaft that rotates in the casing, and several sub shafts that revolve in conjunction with the rotation of the main shaft, and a large number of ring-shaped grinding media are attached to each sub shaft. The size of the ring as the grinding medium depends on the device type,
The outer diameter is 25 to 45 mm and the thickness is about several mm. A gap of several mm is provided between the counter shaft and the inner diameter of the outer ring-shaped grinding medium, and the rings can individually function freely. With the rotation of the main shaft, the ring that functions as this grinding medium moves in the radial direction by the gap due to the centrifugal force generated, and circulates inside the casing while being pressed against the inner wall of the casing. Due to friction or the like, it itself rotates around the auxiliary shaft. That is, the ring is moving in the casing while repeating its revolution and rotation, and the starch particles are sandwiched between this rotating ring and the wall surface, and the compression force due to the centrifugal force of the ring and the rotation of the ring itself. Grinding and dispersion are performed by the action of the grinding force (compression and shearing) by the.
Since each ring can rotate independently and freely, even if the raw material contains large or small starch particles, each ring can freely give a crushing action to the starch particles. it can. Vessel total volume 1
The modification treatment was carried out using 0.7 liter of Micros MC-5. Ethanol 24 as a dispersion medium in the vessel
00 g and 600 g of commercially available corn starch (water content 11.9%) having an average particle size of 17.0 micrometers (μm) were added, sealed, and treated at a rotation speed of 975 rpm for 60 minutes, and subsequently at a rotation speed of 1200 rpm for 20 hours. To modify the corn starch. At this time, cooling water (10 ° C.) was circulated in the jacket portion of the vessel to control the temperature rise in the apparatus. After the modified starch was dried, the particles were observed with a SEM (scanning electron microscope). The starch was deformed into a flat shape after 60 minutes of treatment.
In the treatment for 0 hour, the starch deformed into a flat shape was torn off and ruptured to become a finely deformed starch. As a result, modified corn starch was obtained in which the specific surface area of the starch particles was remarkably increased and other physical properties shown in Table 1 below were remarkably changed. The measurement results are shown in Table 1. [Example 2] Preparation of Modified Potato Starch As the particulate material treatment device, Micros MIC-2 (manufactured by Nara Machinery Co., Ltd.) having a vessel total volume of 3.8 liters was used while controlling the temperature rise with cooling water. The potato starch was modified. Commercially available potato starch (water content: 16.2%) 30 having 1500 g of ethanol as a dispersion medium and an average particle size of 30.5 micrometers (μm) in the beth cell
0 g was added and sealed. After drying the treated starch, SE
The particles were observed with M, but when processed at a rotation speed of 1000 rpm for 30 minutes, starch was deformed into a flat shape, and the rotation speed was 145
When treated at 0 rpm for 6 hours, the starch deformed in a flat shape was torn off and ruptured to become a starch deformed into fine particles. As a result, modified potato starch was obtained in which the specific surface area of the starch particles was remarkably increased and the other physical properties shown in Table 1 below were remarkably changed. The measurement results are shown in Table 1. [Example 3] Preparation of modified tapioca starch The tapioca starch was modified using the same particulate material processing apparatus as in Example 2. The dispersion medium was ethanol and the same amount was used. The treatment was performed by adding 300 g of commercially available tapioca starch (water content 11.8%) having an average particle size of 15.1 micrometers (μm). After the treated starch was dried, the particles were observed by SEM. When treated at a rotation speed of 1450 rpm for 30 minutes, the starch became deformed into a flat shape, and the rotation speed was 1450 rpm.
During the time treatment, the starch that had deformed to a flat shape was torn off and ruptured to become a starch that had deformed into fine particles. As a result, a modified tapioca starch was obtained in which the specific surface area of the starch particles was remarkably increased and the other physical properties shown in Table 1 below were remarkably changed. The measurement results are shown in Table 1.

[Table 1] In Table 1, the average particle size is measured by the laser light diffraction scattering method,
For the X-ray diffraction pattern, a self-recording diffractometer was used.
The specific surface area of the starch particles was measured by the BET method using a mixed gas of nitrogen and helium. In Table 1, Form A, Form B, and Form C in the X-ray diffraction pattern of untreated starch are based on the explanation in page 190 of Starch Handbook (Asakura Shoten, 5th edition, 1965). According to Examples 1 to 3, as shown in Table 1, corn starch, potato starch, and tapioca starch were treated by the particulate material processing apparatus for imparting a certain mechanical energy used in the present invention, regardless of plant species. The starch particles were deformed into a flat shape, or the starch particles deformed into a flat shape were torn off and ruptured and deformed into fine particles. The specific surface area of the starch particles increased to 2.5 times or more that of the untreated starch along with the change of the average particle size and the disappearance of the X-ray diffraction pattern, and the modified starch which was the object of the present invention was obtained. [Comparative Example 1] 20 g of the same corn starch as in Example 1 was placed in a laboratory planetary ball mill (capacity 0.5 liter),
Filled with agate ball 30% and sealed, rotation speed 360r
It was treated with pm for 1 hour. As a result, SEM observation showed that the surface of the corn starch particles was considerably cracked, but no atomization was observed. In X-ray diffraction, the A pattern disappeared and the specific surface area of the starch particles did not change. From this, even if a compressive force and a frictional force are applied, the crystal structure is changed by the planetary ball mill treatment for a lab, but the formation of a new surface of corn starch particles does not occur, and the modified starch as in the present invention is obtained. It turns out to be difficult. The measurement results are shown in Table 2 together with the measurement results of Example 1 above. [Comparative Example 2] A high-speed rotary impact crusher (HYB-O type manufactured by Nara Machinery Co., Ltd.) was used as a device. The same corn starch as in Example 1 (60 g) was rotated at a speed of 16200.
Processed at rpm for 1 hour. As a result, the SEM observation did not show any change in the corn starch particle state, but the average particle size was slightly smaller. The X-ray diffraction and the specific surface area of the starch particles did not change. From this, it is understood that it is difficult to obtain the modified starch as in the present invention by the high-speed rotary impact pulverizer treatment by impact force. The measurement results are shown in Table 2 together with the measurement results of Example 1 above. [Comparative Example 3] A counter jet mill (200AFG type, manufactured by Hosokawa Micron Corporation) was used as an apparatus. The same corn starch as in Example 1 was rotated at a rotational speed of 11,1.
It was processed at 50 rpm and a supply capacity of 5 kg / hrs. The result was that corn starch was considerably smaller by SEM observation. X-ray diffraction was unchanged. The specific surface area of the starch particles was slightly larger. From this, it is possible that the impact force of the counter jet mill can activate the surface of the corn starch, but it does not reach the requirement that a modified starch can be obtained as in the present invention. It can be seen that it is difficult to obtain such modified starch. The measurement results are shown in Table 2 together with the measurement results of Example 1 above.

[Table 2] The measuring method and the like are the same as those in Table 1 above. As is clear from Table 2, as compared with the specific surface area of the starch particles obtained in Example 1 or Examples 2 and 3, the specific surface area of the starch particles obtained in Comparative Examples 1 to 3 is the average particle size. It can be seen that the specific surface area of the starch particles is unlikely to change regardless of the size of.

INDUSTRIAL APPLICABILITY According to the present invention described in detail above, starch particles are ruptured by mechanical energy of any one or two of compression force, impact force, grinding force and shearing force. Without deforming into a flat shape, or the starch particles deformed into a flat shape are broken by mechanical energy of any one or more of compression force, impact force, attrition force, and shearing force. It is possible to provide a modified starch in which the specific surface area of the starch particles is remarkably changed and a method for producing the modified starch, by transforming into fine particles. Since the modified starch obtained in the present invention has a newly formed surface on the surface of the particles, the specific surface area of the starch particles is remarkably large. Therefore, the modified starch has a new physicochemical property different from that of the conventional modified starch. Various industrial applications can be expected.

Claims (10)

[Claims] 1. The starch is deformed into a flat shape without breaking the particles by mechanical energy of one or more of compression force, impact force, grinding force and shearing force, or the starch is flattened. The starch particles that have been deformed into a shape are ruptured by the mechanical energy of any one or two or more of compression force, impact force, grinding force, and shearing force to be transformed into fine particles. Modified starch having a specific surface area of 2.5 times or more that of untreated starch. 2. The starch is deformed into a flat shape without breaking the particles by the mechanical energy of one or more of compression force, impact force, grinding force and shearing force, or the starch is flattened. The starch particles that have been deformed into a shape are ruptured by the mechanical energy of any one or two or more of compression force, impact force, grinding force, and shearing force to be transformed into fine particles. Has a specific surface area of 2.5 times or more that of untreated starch, and an X-ray diffraction pattern peculiar to starch (regularity of fine crystals scattered in starch particles)
A modified starch characterized in that the starch disappears. 3. The modified starch according to claim 1, wherein the starch particles deformed into a flat shape have an average particle size larger or smaller than an average particle size of untreated starch. 4. The modified starch according to claim 1 or 2, wherein the average particle size of the finely modified starch particles is not more than half the average particle size of the untreated starch. 5. The starch is corn starch, high-amylose corn starch, waxy corn starch, sorghum starch, potato starch, sweet potato starch, tapioca starch, sago starch, bean starch, wheat starch, barley starch, rice starch,
The modified starch according to claim 1 or 2, which is one or more selected from the group consisting of kudzu starch, starch starch, canna starch, arrowroot starch, cross-linked starch and heat-moisture treated starch. 6. The starch is deformed into a flat shape without breaking the particles by mechanical energy of any one kind or two kinds or more of compressive force, impact force, grinding force and shearing force, or the flattened state. Ratio of starch particles by breaking the deformed starch particles by mechanical energy of one or more of compression force, impact force, grinding force, and shearing force and transforming them into fine particles. A method for producing a modified starch, characterized in that the surface area is 2.5 times or more that of untreated starch. 7. The starch is deformed into a flat shape without breaking the particles by mechanical energy of one or more of compression force, impact force, grinding force and shearing force, or the starch is flattened. Ratio of starch particles by breaking the deformed starch particles by mechanical energy of one or more of compression force, impact force, grinding force, and shearing force and transforming them into fine particles. A method for producing a modified starch, characterized in that the surface area is 2.5 times or more that of untreated starch, and the X-ray diffraction pattern peculiar to starch disappears. 8. The method for producing a modified starch according to claim 6, wherein the average particle size of the flatly deformed starch particles is larger or smaller than the average particle size of untreated starch. . 9. The average particle size of the starch particles which have been transformed into fine particles is not more than half the average particle size of the untreated starch.
Or a method for producing the modified starch according to item 7. 10. The starch is corn starch, high amylose corn starch, waxy corn starch, sorghum starch, potato starch, sweet potato starch, tapioca starch, sago starch, bean starch, wheat starch, barley starch, rice starch,
The method for producing a modified starch according to claim 6 or 7, which is one or more selected from among kudzu starch, starch starch, canna starch, arrowroot starch, cross-linked starch and heat-moisture treated starch.