Method for separating starch granules from rice, starch granules and application

Abstract

The invention provides a method for separating starch granules from rice, the starch granules and application of the starch granules, large, medium and small granules in rice flour are gradually dissociated into the starch granules in a graded manner through four sequential steps of soaking, pulping, stirring at constant temperature and passing through a colloid mill, and a starch granule product is obtained after freeze-drying. The particle size of more than 90% of the particles is less than 10 [mu] m (D90 is less than 10 [mu] m), the volume average diameter D [4, 3] is less than 6 [mu] m, and the yield of the starch particle product reaches more than 80%. According to the method, no chemical reagent is used, conditions such as ultrasound, microwaves and high pressure are not needed, the process is energy-saving, environment-friendly and efficient, the product is healthy, green and safe, and the starch particle product is uniform, fine, white in color and free of peculiar smell.

Description

Technical Field

[0001] The invention belongs to the technical field of starch granule preparation, and specifically relates to a method for separating starch granules from rice, starch granules and applications. The separated starch granules are used for preparing flavors and fragrances, fat substitutes, pharmaceutical excipients, surface brighteners or cosmetic foundations. Background Art

[0002] With the development of society and the improvement of people's living standards, there is an increasing demand for rice starch granule products in flavors and fragrances, fat substitutes, pharmaceutical excipients and cosmetic foundations. On the one hand, it is hoped that the rice starch granule products will maintain the good natural properties of rice, such as tasteless, white, intact starch granule structure, and low allergy; on the other hand, it is hoped that the separation of rice starch granules is complete and thorough, without large particles, and the preparation process is energy-saving and environmentally friendly, and the starch granule products are uniform and delicate with high yield.

[0003] Among the known cereals, potatoes and beans, rice starch particles have the smallest particle size and the product is the most delicate and smooth; rice starch particles have the highest specific surface area and have strong adsorption, filling and emulsification effects, so rice starch particles have many advantages. First, because rice starch particles themselves are tasteless, they act as flavor adsorbents for flavors and spices without changing the original flavor of the product; and because of their small particles and easy dispersion, they are conducive to the contact between flavor substances and taste buds in the mouth. Second, the particle size of rice starch particles is basically the same as that of fat globules, so they have a delicate and lubricated taste similar to that of fat globules and can be used as a fat substitute. Third, rice starch particles are white in color and can be used as a glossy coating on the surface of candies or tablets. Fourth, rice starch particles have low allergy and high digestibility, and are widely used in infants, special foods and medicines. In addition, after gelatinization, rice starch particles have moderate consistency, fine texture, and are easy to spread. They can be used as thickeners in soups, sauces and instant rice, which can well improve the taste of food.

[0004] At present, the commonly used methods for separating rice starch granules include the alkali method, the surfactant method (SDS) and the bio-enzyme method. However, after the preparation process of the alkali method, salt will be generated through acid-base neutralization, which makes the product salty and corrodes the processing equipment. In addition, alkaline waste liquid will be produced after centrifugation, which increases the cost of wastewater discharge and treatment. The surfactant method has a better separation effect, but SDS is a non-edible surfactant and may cause allergic reactions in certain groups of people. It should be used with caution to avoid certain risks to the safety of the product. The bio-enzyme method separates starch granules, which causes less damage to starch granules than the alkali method and SDS method, but the cost of the enzyme is high, and the enzymatic hydrolysis takes a long time, resulting in low production efficiency.

[0005] The separation of rice starch granules is difficult because not only are the granules small, but the starch granules are also tightly bonded to each other, and the surface of the starch granules is coated with protein, making it even more difficult to separate. How to obtain a rice starch granule product with a small and fine particle size, uniformity, no large particles, and intact starch granule structure, and find an energy-saving, environmentally friendly, safe, green, healthy, and high product yield starch granule separation method, is still a technical problem that needs to be solved. Summary of the invention

[0006] The object of the present invention is to provide a method for separating starch granules from rice. The present invention gradually separates large, medium and small particles in rice flour into starch granules by grading through four sequential steps of soaking, beating, constant temperature stirring and colloid milling, and obtains starch granule products after drying. The present invention does not use any chemical reagents, nor does it require conditions such as ultrasound, microwaves and high pressure. The process of the present invention is energy-saving, environmentally friendly and efficient. The starch granule products are healthy, green, safe, uniform and delicate, and the product yield is high.

[0007] Another object of the present invention is to provide a starch granule prepared by the above method, wherein all the particle sizes are below 20 μm, and 90% of the particle sizes are less than 10 μm (D 90 <10μm), the volume average diameter is less than 6μm, and the product yield is over 80%.

[0008] Another object of the present invention is to provide an application of starch granules for use in the preparation of flavors and fragrances, fat substitutes, pharmaceutical excipients, surface brighteners or cosmetic foundations.

[0009] The specific technical solutions of the present invention are as follows:

[0010] A method for separating starch granules from rice comprises the following steps:

[0011] 1) Grinding rice into rice flour and soaking it;

[0012] 2) beating to obtain rice slurry 1;

[0013] 3) stirring and dissociating the rice slurry 1 at a constant temperature to obtain the rice slurry 2;

[0014] 4) passing through a colloid mill to obtain a starch granule suspension;

[0015] 5) Centrifugation to obtain starch granule precipitation;

[0016] 6) The starch granules are precipitated, freeze-dried, and ground to obtain a starch granule product.

[0017] In step 1), the rice is crushed into rice flour with more than 95% passing through a sieve with an aperture of 450 μm, and then water is added at a mass ratio of rice flour to water of 1:5, and the mixture is stirred at room temperature and pressure, and soaked for 1 hour. In this step, the rice is first crushed into rice flour and then soaked, so that the rice flour is soaked instead of the rice grains, so that the starch and protein can be hydrated and expanded in a short time.

[0018] In step 2), the beating is performed at 24000 r / min for 3-6 min to obtain rice slurry 1; the beating is performed using a beater (food processor) to convert large particles in the rice flour into small and medium particles or starch granules.

[0019] In step 3), the rice slurry 1 is stirred and dissociated for 90-150 min at a temperature of 35-45 ° C, and passed through a 75 μm screen to obtain the rice slurry 2; preferably, the rice slurry is stirred and dissociated for 120 min at a constant temperature of 40 ° C. By carrying out constant temperature stirring, the medium-sized particles are dissociated into small particles, and the immersion of this process increases the elasticity of the starch granules to reduce the damage when passing through the colloid mill, and promote the separation effect of the subsequent colloid mill.

[0020] In step 4), the slit scale of the colloid mill is adjusted to 3-5 (the gap scale between the moving teeth and the static teeth), and the rice slurry 2 is circulated in the colloid mill at room temperature for 2-5 minutes to obtain a starch granule suspension. The slit between the moving teeth and the static teeth can be freely adjusted between 10-1000 μm. The slit scale of the present invention is set to 3-5, the cycle grinding time is 2-5 minutes, and the small particles are separated into starch particles by grinding through the colloid mill; the colloid mill is a concentric rotating colloid mill.

[0021] In step 5), the starch granule suspension is centrifuged at 4000 r / min for 10 min, the supernatant is decanted, the yellow soft matter on the surface of the precipitate is scraped off, the surface of the precipitate is washed twice, and then centrifuged once under the same conditions, and the supernatant is decanted to obtain a starch granule precipitate;

[0022] In step 6), the starch granule precipitate is transferred to a culture dish with a pre-constant weight, sealed with plastic wrap, first frozen at -18°C for 24 hours, then holes are pierced in the plastic wrap, freeze-dried at a cold trap temperature of -68°C for 48 hours, and ground to pass a 75 μm sieve to obtain a starch granule solid powder.

[0023] The starch granule product provided by the present invention is prepared by the above method. The particle sizes of all particles in the prepared starch granule product are below 20 μm, among which more than 90% of the particle sizes are less than 10 μm, the volume average diameter D[4,3] is less than 6 μm, and the starch granule product yield reaches more than 80%.

[0024] The present invention separates the starch granules that are bonded and aggregated together in rice to prepare discrete starch granule products. The starch granule separation method of the present invention refers to separating the starch granules from each other to form individual starch granules with basically the same particle size (all particles are less than 20 μm), and then drying to obtain the starch granule product; it does not refer to graded separation of a mixture of particles with different particle sizes (because large particles are not completely depolymerized and separated, only graded separation will still cause large particles to exist, making it difficult to screen and causing a reduction in product yield), so the yield of the starch granule product obtained by the present invention is higher.

[0025] The technical principle of the present invention is: gradually graded dissociation and dispersion, the rice flour particles gradually decrease from large to small, and the number of dissociated and dispersed starch particles increases from small to large. Through soaking, starch and protein are hydrated and expanded, laying the foundation for subsequent beating dissociation and dispersion; secondly, through beating, on the one hand, large particles in rice flour are turned into medium and small particles, and on the other hand, starch particles outside the larger particles in rice flour are separated from the parent particles and become free starch particles; then, through constant temperature stirring, the starch particles and the protein in the gaps are further swollen to increase the gap between the starch particles, and the elasticity of the starch particles is increased to reduce the damage when passing through the colloid mill, and in addition, the medium-sized particles are dissociated into small particles; finally, the small particles are separated into starch particles by the shear force and friction force between the moving teeth and the static teeth of the colloid mill, and the high-frequency vibration and high-speed vortex. That is, through the four sequential steps of soaking, beating, constant temperature stirring, and passing through the colloid mill, the large, medium and small particles in the rice flour are gradually graded and dissociated into starch particles, and the starch particle product is obtained after drying. The method for separating starch particles from rice of the present invention has the advantages of energy-saving, environmental protection, high efficiency, low cost, green, healthy, safe and pollution-free products, fine and uniform particles and high product yield.

[0026] The starch granules provided by the present invention are used for preparing materials for flavors and fragrances, fat substitutes, pharmaceutical excipients, surface brighteners or cosmetic foundations.

[0027] Compared with the prior art, the present invention does not use alkali solution, surfactant or biological enzyme. There is a large gap between the moving teeth and the static teeth of the colloid mill, so the damage to starch particles is small, the material loss is small, the cost is low, and the pure physical method is adopted. Therefore, the obtained product is healthy and safe, and the equipment will not be corroded by salt generated by acid-base neutralization; the process time is short and the efficiency is high; the beating and colloid milling time is short and the energy consumption is low; the product yield is high, reaching more than 80%; the particle size is small, and the particle size of all particles is below 20μm, D 90Less than 10μm, D[4,3] less than 6μm; large specific surface area, white color, no odor such as alkali or surfactant. It meets the requirements of energy saving, environmental protection, green, health, safety, and high product yield. It has important applications in the fields of flavors and fragrances, fat substitutes, pharmaceutical excipients, surface brighteners or cosmetic foundations. The starch granule products obtained can also be used to study the relationship between rice functional properties and starch granule structure. The colloid mill used has a simple structure, low equipment price, and easy maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a particle size distribution diagram of the starch granule product of Example 1 (dotted line) and Comparative Example 5 (empty triangle line) and rice flour (black thick line);

[0029] Figure 2 Optical microscope images of the starch granule product (left) and rice flour (right) of Example 1;

[0030] Figure 3 The following are scanning electron microscope images of the starch granule product (left) and rice flour (right) of Example 1. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0033] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0034] Example 1

[0035] A method for separating starch granules from rice comprises the following steps:

[0036] 1) Crush the rice with a high-speed universal grinder (FW-100) until more than 95% of the rice passes through a 450 μm sieve, take 10 g of rice flour under the 450 μm sieve, then add 50 mL of water, stir well at room temperature and pressure, and soak for 1 hour;

[0037] 2) The system after soaking in step 1) was beaten with a beater at 24000 r / min for 4 min to obtain rice slurry 1;

[0038] 3) stirring the rice slurry 1 at a constant temperature of 1000 r / min for 120 min at 40° C. and passing the mixture through a 75 μm sieve to obtain rice slurry 2;

[0039] 4) using an L-50 vertical colloid mill, adjusting the slit scale of the colloid mill to 5, and grinding the rice slurry 2 in the colloid mill at room temperature for 3 min to obtain a starch granule suspension;

[0040] 5) The starch granule suspension obtained above was centrifuged at 4000 r / min for 10 min, the supernatant was decanted, the yellow soft matter on the surface of the precipitate was scraped off, the surface of the precipitate was washed twice with 20 mL of water, and then centrifuged once under the same conditions, and the supernatant was decanted to obtain starch granule precipitate;

[0041] 6) Transfer the starch granule precipitate to a pre-weighted culture dish, seal it with plastic wrap, freeze it at -18°C for 24 hours, then punch holes in the plastic wrap, freeze-dry it at a cold trap temperature of -68°C for 48 hours, and weigh it. After freeze-drying, grind it into powder with a mortar to pass through a 75 μm sieve to obtain a starch granule solid powder.

[0042] The product yield is calculated based on the ratio of the mass of the obtained starch granule product to the mass of the rice flour.

[0043] The following method was used to determine the particle size distribution of the sample: 0.100 g of solid powder was weighed, 10 mL of distilled water was added, and the mixture was mixed with a vortex mixer for 1 min, and then the particle size distribution was determined using a laser particle size analyzer (MS2000, Malvern Instruments Ltd., UK). Determination conditions: the dispersant was distilled water, the rotation speed was 1500 r / min, the determination mode was manual, and the dispersion mode was polydisperse. The sample was shaken, 4 mL of the suspension was slowly injected into the dispersant with a pipette until the shading degree was between 10% and 20%, and the particle size distribution was determined.

[0044] In the above Example 1, the volume average diameter D[4,3] of the rice starch granule sample is 5.512 μm, and more than 90% of the granules have a diameter of 9.353 μm (D 90 ), all particle sizes are below 20 μm, uniform and fine, and the product yield is 84.20%.

[0045] The particle size distribution of the starch granules obtained by the above process and the raw rice flour is as follows: Figure 1 As shown, it can be seen that D[4,3]: rice flour 210 μm, Example 1 is 5.512 μm, and Comparative Example 5 is 8.133 μm; D 90 : Rice flour 483μm, Example 1 is 9.353μm, and Comparative Example 5 is 11.123μm; Example 1 has no large particle size peak, while Comparative Example 5 still has a large particle size peak of 20-121μm.

[0046] Example 1 Optical microscope images and scanning electron microscope images are shown in Figure 2 and Figure 3 .Depend on Figures 1 to 3 It can be seen that the starch granule product obtained in Example 1 has small particles, uniform size, complete separation, no large particles larger than 20 μm, and good quality.

[0047] Example 2

[0048] A method for separating starch granules from rice comprises the following steps:

[0049] 1) Crush rice with a cyclone grinder until more than 95% of the rice passes through a 450 μm sieve, take 10 g of rice flour under the 450 μm sieve, then add 50 mL of water, stir well at room temperature and pressure, and soak for 1 hour;

[0050] 2) beating the mixture with a rotary paddle beater at 24000 r / min for 4 min to obtain rice slurry 1;

[0051] 3) stirring the rice slurry 1 at a constant temperature of 40° C. for 120 min, and passing the mixture through a 75 μm sieve to obtain rice slurry 2;

[0052] 4) adjusting the slit scale of the colloid mill to 3, and grinding the rice slurry 2 in the colloid mill at room temperature for 3 min to obtain a starch granule suspension;

[0053] 5) The starch granule suspension obtained above was centrifuged at 4000 r / min for 10 min, the supernatant was decanted, the yellow soft matter on the surface of the precipitate was scraped off, the surface of the precipitate was washed twice with 20 mL of water, and then centrifuged once under the same conditions, and the supernatant was decanted to obtain starch granule precipitate;

[0054] 6) Transfer the starch granule precipitate to a pre-weighted culture dish, seal it with plastic wrap, freeze it at -18°C for 24 hours, then punch holes in the plastic wrap, freeze-dry it at a cold trap temperature of -68°C for 48 hours, and weigh it. After freeze-drying, grind it into powder with a mortar to pass through a 75 μm sieve to obtain a starch granule solid powder.

[0055] In the above Example 2, the volume average diameter D[4,3] of the rice starch granule sample is 5.627 μm, and more than 90% of the granules have a diameter of 9.542 μm (D 90 ), all particle sizes are below 20 μm, uniform and fine, and the product yield is 83.55%.

[0056] Example 3

[0057] A method for separating starch granules from rice comprises the following steps:

[0058] 1) Crush rice with a cyclone grinder until more than 95% of the rice passes through a 450 μm sieve, take 10 g of rice flour under the 450 μm sieve, then add 50 mL of water, stir well at room temperature and pressure, and soak for 1 hour;

[0059] 2) beating the mixture with a rotary paddle beater at 24000 r / min for 6 min to obtain rice slurry 1;

[0060] 3) stirring the rice slurry 1 at a constant temperature of 40° C. for 110 min, and passing the mixture through a 75 μm sieve to obtain rice slurry 2;

[0061] 4) adjusting the slit scale of the colloid mill to 5, and grinding the rice slurry 2 in the colloid mill at room temperature for 3 min to obtain a starch granule suspension;

[0062] 5) The starch granule suspension obtained above was centrifuged at 4000 r / min for 10 min, the supernatant was decanted, the yellow soft matter on the surface of the precipitate was scraped off, the surface of the precipitate was washed twice with 20 mL of water, and then centrifuged once under the same conditions, and the supernatant was decanted to obtain starch granule precipitate;

[0063] 6) Transfer the starch granule precipitate to a pre-weighted culture dish, seal it with plastic wrap, freeze it at -18°C for 24 hours, then punch holes in the plastic wrap, freeze-dry it at a cold trap temperature of -68°C for 48 hours, and weigh it. After freeze-drying, grind it into powder with a mortar to pass through a 75 μm sieve to obtain a starch granule solid powder.

[0064] In the above Example 3, the volume average diameter D[4,3] of the rice starch granule sample is 5.371 μm, and more than 90% of the granules have a diameter of 9.124 μm (D 90 ), all particle sizes are below 20 μm, uniform and fine, and the product yield is 83.56%.

[0065] The method of the invention can ensure that the rice starch particles in the product are completely separated without any remaining large particles (no particles larger than 20 μm), which is a basic requirement. Otherwise, the product will be uneven, have a sandy feel, and affect the scope of use and effect.

[0066] Comparative Example 1

[0067] According to Example 1, but in step 1), after stirring, do not soak, and directly proceed to step 2).

[0068] In the comparative example 1, the volume average diameter D[4,3] of the rice starch granule sample is 7.557 μm, which is more than 6 μm. 90 The particle size is 10.593 μm, which is more than 10 μm, and there are large particles of 20-105 μm. The overall particle size does not meet the uniform and fine requirements, and the starch granules are not completely separated.

[0069] Comparative Example 2

[0070] As in Example 1, but without step 2).

[0071] In the comparative example 2, the volume average diameter D[4,3] of the rice starch granule sample is 7.916 μm, which is more than 6 μm. 90 The particle size is 11.094 μm, which exceeds 10 μm, and there are large particles of 20-92 μm. The overall particle size does not meet the uniform and fine requirements, and the starch particles are not completely separated.

[0072] Comparative Example 3

[0073] According to Example 1, the beating time in step 2) is reduced from the original 4 min to 2 min, and the other steps are the same.

[0074] In the above comparative example 3, the volume average diameter D[4,3] of the rice starch granule sample is 7.585 μm, which is more than 6 μm. 90 It is 10.936μm, which exceeds 10μm, and there are large particles of 20-92μm. The overall requirement of uniformity and fineness is not met, and the separation of starch particles is incomplete.

[0075] Comparative Example 4

[0076] As in Example 1, but without step 3).

[0077] In the comparative example 4, the volume average diameter D[4,3] of the rice starch granule sample is 9.448 μm, which is more than 6 μm. 90 It is 11.726μm, which exceeds 10μm, and there are large particles of 20-182μm. The overall requirement of uniformity and fineness is not met, and the separation of starch particles is incomplete.

[0078] Comparative Example 5

[0079] According to Example 1, the constant temperature stirring time in step 3) is reduced from 120 min to 60 min, and the other steps are the same.

[0080] In the above comparative example 5, the volume average diameter D[4,3] of the rice starch granule sample is 8.133 μm, which is more than 6 μm. 90 The size of the starch is 11.123 μm, which exceeds 10 μm, and there are large particles of 20-121 μm. The overall size does not meet the requirements of uniformity and fineness, and the separation of starch particles is incomplete.

[0081] Comparative Example 6

[0082] According to Example 1, the constant temperature stirring temperature is reduced from 40° C. to 20° C. in step 3), and the other steps are the same.

[0083] In the above comparative example 6, the volume average diameter D[4,3] of the rice starch granule sample is 7.603 μm, which is more than 6 μm.90 It is 10.514μm, which exceeds 10μm, and there are large particles of 20-121μm. The overall size does not meet the uniform and fine requirements, and the starch granules are not completely separated.

[0084] Comparative Example 7

[0085] The method is as in Example 1, but without the colloid mill in step 4).

[0086] In the above comparative example 7, the volume average diameter D[4,3] of the rice starch granule sample is 8.132 μm, which is greater than 6 μm. 90 The particle size is 11.241μm, exceeding 10μm, and there are large particles of 20-105μm. The overall particle size does not meet the uniform and fine requirements, and the starch granules are not completely separated.

[0087] Comparative Example 8

[0088] As in Example 1, but in step 4), the slit scale of the colloid mill is increased from 5 to 8.

[0089] In the comparative example 8, the volume average diameter D[4,3] of the rice starch granule sample is 6.806 μm, which is more than 6 μm. 90 The particle size is 10.195 μm, which exceeds 10 μm, and there are large particles of 20-92 μm. The overall particle size does not meet the uniform and fine requirements, and the starch granules are not completely separated.

[0090] Comparative Example 9

[0091] A method for separating starch granules from rice comprises the following steps:

[0092] 1) Crush rice with a cyclone grinder until more than 95% of the rice passes through a 450 μm sieve, take 10 g of rice flour under the 450 μm sieve, then add 50 mL of water, stir well at room temperature and pressure, and soak for 1 hour;

[0093] 2) beating the mixture with a rotary paddle beater at 24000 r / min for 5 min to obtain rice slurry 1;

[0094] 3) stirring the rice slurry 1 at a constant temperature of 40° C. for 120 min, and passing the mixture through a 75 μm sieve to obtain rice slurry 2;

[0095] 4) adjusting the slit scale of the colloid mill to 6, and grinding the rice slurry 2 in the colloid mill at room temperature for 5 min to obtain a starch granule suspension;

[0096] 5) The starch granule suspension obtained above was centrifuged at 4000 r / min for 10 min, the supernatant was decanted, the yellow soft matter on the surface of the precipitate was scraped off, the surface of the precipitate was washed twice with 20 mL of water, and then centrifuged once under the same conditions, and the supernatant was decanted to obtain starch granule precipitate;

[0097] 6) Transfer the starch granule precipitate to a pre-weighted culture dish, seal it with plastic wrap, freeze it at -18°C for 24 hours, then punch holes in the plastic wrap, freeze-dry it at a cold trap temperature of -68°C for 48 hours, and weigh it. After freeze-drying, grind it into powder with a mortar to pass through a 75 μm sieve to obtain a starch granule solid powder.

[0098] In the above comparative example 9, the slit scale is adjusted to 6, which is relatively large; the volume average diameter D[4,3] of the obtained rice starch granule sample is 7.526 μm, which is more than 6 μm, and D 90 It is 10.441μm, which exceeds 10μm, and there are large particles of 20-105μm. The overall size does not meet the uniform and fine requirements, and the starch granules are not completely separated.

[0099] Comparative Example 10

[0100] A method for separating starch granules from rice comprises the following steps:

[0101] 1) Crush rice with a cyclone grinder until more than 95% of the rice passes through a 450 μm sieve, take 10 g of rice flour under the 450 μm sieve, then add 50 mL of water, stir well at room temperature and pressure, and soak for 1 hour;

[0102] 2) beating the mixture with a rotary paddle beater at 24000 r / min for 4 min to obtain rice slurry 1;

[0103] 3) stirring the rice slurry 1 at a constant temperature of 50° C. for 100 min, and passing the mixture through a 75 μm sieve to obtain rice slurry 2;

[0104] 4) adjusting the slit scale of the colloid mill to 5, and grinding the rice slurry 2 in the colloid mill at room temperature for 4 min to obtain a starch granule suspension;

[0105] 5) The starch granule suspension obtained above was centrifuged at 4000 r / min for 10 min, the supernatant was decanted, the yellow soft matter on the surface of the precipitate was scraped off, the surface of the precipitate was washed twice with 20 mL of water, and then centrifuged once under the same conditions, and the supernatant was decanted to obtain starch granule precipitate;

[0106] 6) Transfer the starch granule precipitate to a pre-weighted culture dish, seal it with plastic wrap, freeze it at -18°C for 24 hours, then punch holes in the plastic wrap, freeze-dry it at a cold trap temperature of -68°C for 48 hours, and weigh it. After freeze-drying, grind it into powder with a mortar to pass through a 75 μm sieve to obtain a starch granule solid powder.

[0107] In the comparative example 10, the constant temperature stirring temperature is 50°C, which is relatively high. The volume average diameter D[4,3] of the obtained rice starch granule sample is 7.681 μm, which is more than 6 μm. 90It is 10.718μm, which exceeds 10μm, and there are large particles of 20-105μm. The overall size does not meet the uniform and fine requirements, and the starch granules are not completely separated.

[0108] In the present invention, the four steps of soaking, beating, constant temperature stirring dissociation and colloid milling are coordinated to gradually grade and dissociate large, medium and small particles in rice flour into starch particles without using any chemical reagents or biological enzymes, thereby avoiding acid, alkali and salt corrosion of equipment; the product yield is high, the volume average diameter of the product is low, and the degree of starch particle separation is high; the entire process is energy-saving, environmentally friendly, green, safe, low in energy consumption, and the product has a wide range of application.

[0109] It can also be seen from Comparative Examples 1-10 that even if individual steps are omitted or parameters are not controlled as required, the overall product will not meet the requirements of uniformity and fineness, and the particle size of the particles is less than 20 μm and the particle size of more than 90% of the particles is less than 10 μm (D 90 <10μm), the volume average diameter D[4,3] is less than 6μm, and the starch granule product yield reaches more than 80%.

[0110] The description of the above embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A method for separating starch granules from rice, characterized in that: The method comprises the following steps: 1) Grinding rice into rice flour and soaking it; 2) beating to obtain rice slurry 1; 3) stirring and dissociating the rice slurry 1 at a constant temperature to obtain the rice slurry 2; 4) passing through a colloid mill to obtain a starch granule suspension; 5) Centrifugation to obtain starch granule precipitation; 6) The starch granules are precipitated, freeze-dried, and ground to obtain a starch granule product.

2. The method according to claim 1, characterized in that In step 1), the rice is crushed to obtain rice flour with more than 95% passing through a sieve with an aperture of 450 μm, and then water is added, stirred evenly, and soaked for 1 hour; the mass ratio of rice flour to water is 1:

5.

3. The method according to claim 1, characterized in that: In step 2), the beating is performed at 24000 r / min for 3-6 min.

4. The method according to claim 1, characterized in that: In step 3), the rice milk 1 is stirred at a temperature of 35-45° C. for 90-150 min, and passed through a 75 μm sieve to obtain the rice milk 2.

5. The method according to claim 1, characterized in that: In step 4), the slit scale of the colloid mill is adjusted to 3-5, and the rice slurry 2 is circulated and milled in the colloid mill for 2-5 minutes to obtain a starch granule suspension.

6. The method according to claim 1, characterized in that In step 5), the starch granule suspension is centrifuged at 4000 r / min for 10 min, the supernatant is decanted, the yellow soft matter on the surface of the precipitate is scraped off, the surface of the precipitate is washed twice with water, and then centrifuged once under the same conditions, and the supernatant is decanted to obtain a starch granule precipitate.

7. The method according to claim 1, characterized in that In step 6), the starch granule precipitate is freeze-dried, ground and pulverized to obtain starch granule solid powder.

8. A starch granule prepared by the method according to any one of claims 1 to 7, characterized in that: The particle sizes of all particles in the prepared starch granule products are all below 20 μm, of which more than 90% have particle sizes less than 10 μm, the volume average diameter D[4,3] is less than 6 μm, and the starch granule product yield reaches more than 80%.

9. An application of the starch granules according to claim 8, characterized in that: Used in the preparation of flavors and fragrances, fat substitutes, pharmaceutical excipients, surface brighteners or cosmetic foundations.

Images