A method and device for precision grading of rice bran

Abstract

The application discloses a precision grading processing method and device for rice bran. Since the composition of the rice bran obtained by different means is quite different, the rice bran can only be used as feed in many cases, which causes great waste of resources. The application utilizes a special rice mill to precisely and flexibly mill brown rice. By setting different rotary cutter blade angles, different scraper rotating speeds, and cooperating with the air direction, air flow and speed of a fan, the rice milling precision and the rice bran precision can be controlled by multiple parameters, the difference of the component composition in each rice bran layer is controlled, the protein, fat, ash content, total starch and DF content of the rice bran present a regular change trend, and conditions for subsequently improving the application value of the rice bran are provided.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization of grain by-products. More specifically, it relates to a method and apparatus for the precise grading and processing of rice bran. Background Technology

[0002] Rice is one of my country's main food crops.

[0003] Rice bran is a byproduct of rice milling after hulling. The caryopsis (the outer pericarp) of rice is brown rice, and after peeling, white rice and rice bran are obtained. Rice bran accounts for about 10% of the weight of brown rice and is rich in various bioactive substances such as starch, protein, fat, dietary fiber, ash, water, vitamins, minerals, γ-oryzanol, ferulic acid, and tocopherol. However, the nutritional composition of rice bran varies depending on the rice variety, milling pretreatment, milling equipment, and degree of milling. This results in irregular and significant differences in the distribution of bioactive substances such as starch, protein, fat, dietary fiber, and ash in different layers of rice bran. Often, rice bran can only be used as animal feed, leading to a significant waste of resources and severely hindering its graded utilization. Therefore, how to accurately control the distribution of bioactive substances in rice bran after milling pretreatment has been a research focus. Summary of the Invention

[0004] To address the aforementioned shortcomings, one objective of this invention is to provide a precise grading and processing method for rice bran. Brown rice is precisely graded using a rice milling machine, resulting in rice bran containing bioactive substances exhibiting a regular variation trend. This provides raw material preparation for further targeted improvements in the application value of rice bran.

[0005] Another object of the present invention is to provide graded rice bran obtained by the precise grading processing method described above.

[0006] To achieve the first objective mentioned above, the present invention adopts the following technical solution:

[0007] This invention provides a method for precise grading and processing of rice bran, the method comprising the following steps:

[0008] 1) Mill brown rice using a rice milling machine, controlling the hulling rate to be 0-2%, but not 0%, to obtain 1 st Rice bran and 1 st brown rice;

[0009] 2) Place 1 st Brown rice is milled using a rice milling machine, with the husk removal rate controlled at 2-4%, yielding 2 nd Rice bran and 2 nd brown rice;

[0010] 3) Place 2 ndThe brown rice is milled by a rice mill, and the husking rate is controlled to be 4-6%, to obtain 3 rd Rice bran and 3 rd Brown rice;

[0011] 4) 3 rd The brown rice is milled by a rice mill, and the husking rate is controlled to be 6-8%, to obtain 4 th Rice bran and 4 th Brown rice;

[0012] 5) 4 th The brown rice is milled by a rice mill, and the husking rate is controlled to be 8-10%, to obtain 5 th Rice bran and 5 th Brown rice;

[0013] 6) 5 th The brown rice is milled by a rice mill, and the husking rate is controlled to be 10-12%, to obtain 6 th Rice bran and 6 th Brown rice;

[0014] 7) 6 th The brown rice is milled by a rice mill, and the husking rate is controlled to be 12-14%, to obtain 7 th Rice bran and 7 th Brown rice; the error of the husking rate is controlled to be within 0.05%;

[0015] 8) The rice bran of each bran layer is collected respectively, and then the rice bran of each bran layer is subjected to a stabilization treatment.

[0016] In view of the problem that the components in different anatomical layers of rice bran in the prior art are quite different, the inventors rely on a special rice mill to perform accurate and flexible milling of brown rice, so that the difference in the component composition of the rice bran in each bran layer is controlled, and the component composition presents a regular change trend. In the present application, the brown rice is put into the first rotary knife and the first mesh cage from the feeding port, and after rubbing and scraping, 1 st Rice bran and 1 st Brown rice, 1 st Brown rice is subjected to rubbing and scraping by the second rotary knife and the second mesh cage, to obtain 2 nd Rice bran and 2 nd Brown rice, and a plurality of milling units can be set in the rice mill according to the experimental needs, and 1 st ~7 th Rice bran and 1 st ~7 th Rice bran are recorded in turn. It is found through research that the difference in the component composition of the rice bran in each bran layer is finally controlled through the design of the rice mill and the control of the working parameters of the rice mill, so that the protein, fat, ash content, total starch and DF content present a regular change trend, which provides conditions for improving the application value of rice bran in a targeted manner.

[0017] Further, the parameters of the rice mill are as follows: air speed is 7.6-14.1 m / min, exhaust pressure is 0.75-1.25 Mpa, air inlet angle is 25-30°, cutter angle is 10-20°, and feeding amount is 2 kg / min. 3

[0018] Further, the stabilization treatment can improve the utilization rate of rice bran. At present, the main rice bran stabilization methods include dry heat method, extrusion puffing, microwave heating, superheated steam, ultrasonic, ultraviolet, chemical reagent stabilization method such as phosphoric acid and acetic acid, and biological stabilization method such as pepsin and papain. In the dry heat method, the enzyme activity is easy to recover, the microwave method has limited penetration depth, and in the chemical method, the reagent is easy to enter the rice bran oil and rice bran meal, affecting the subsequent high-value utilization of rice bran. The extrusion puffing method is simple to operate, high in working efficiency, and the technology applied to the enterprise rice bran stabilization is also mature.

[0019] Further, the brown rice is selected from pearl brown rice or long-grain fragrant brown rice.

[0020] In a specific embodiment, the component content of the 1 st rice bran, 2 nd rice bran and 3 rd rice bran needs to be limited, and the goal is to obtain high-fat, high-protein, high-mineral content, high-dietary fiber, and low-starch content of high-quality bran layer. Specifically, the fat content of the 1 st rice bran, 2 nd rice bran and 3 rd rice bran is ≥18%, the protein content is ≥13%, the ash content is ≥9%, the dietary fiber is ≥23%, and the starch content is ≤20%.

[0021] In a specific embodiment, the component content of the 4 th rice bran, 5 th rice bran and 6 th rice bran needs to be limited, and the goal is to obtain medium-fat, medium-protein, medium-mineral content, medium-dietary fiber, and medium-starch content of medium bran layer. Specifically, the fat content of the 4 th rice bran, 5 th rice bran and 6 th rice bran is ≥7.2%, the protein content is ≥10.3%, the ash content is ≥4.3%, the dietary fiber is ≥5.5%, and the starch content is ≤58.7%.

[0022] In a specific embodiment, the component content of the 7 th rice bran needs to be limited, and the goal is to obtain low-fat, low-protein, low-mineral content, low-dietary fiber, and high-starch content of low-grade bran layer. Specifically, the fat content of the 7 th ​The rice bran has a fat content of ≥6.1%, a protein content of ≥9.5%, an ash content of ≥3.4%, a dietary fiber content of ≥2.8%, and a starch content of ≤63.8%. It should be noted that the skilled person can adjust the above-mentioned contents according to the actual application needs, and the contents of 7 th The brown rice is subjected to rice milling again to obtain 8 th The rice bran and 8 th The brown rice needs to be controlled to have a peeling rate of not more than 15%.

[0023] Further, the present application also discloses a rice mill for realizing the precise grading processing method as described above, so as to solve the problem that the existing rice milling equipment cannot precisely obtain the target rice bran products of various levels through only one device. The rice mill comprises a rice milling mechanism, and the rice milling mechanism comprises at least a first rice milling unit and a second rice milling unit arranged along an X direction.

[0024] The first rice milling unit comprises:

[0025] a first mesh cage with a first rice milling cavity;

[0026] a rotatable first rotating shaft located in the first rice milling cavity; and

[0027] a first rotary knife;

[0028] The first rotary knife is fixed to the outer wall of the first rotating shaft.

[0029] The second rice milling unit comprises:

[0030] a second mesh cage with a second rice milling cavity;

[0031] a rotatable second rotating shaft located in the second rice milling cavity; and

[0032] a second rotary knife;

[0033] The second rotary knife is fixed to the outer wall of the second rotating shaft.

[0034] The first rice milling cavity and the second rice milling cavity are arranged in communication in the X direction.

[0035] The first rotary knife and the second rotary knife have different blade angles.

[0036] The brown rice can enter from one end of the rice milling mechanism, be subjected to rice milling by the first rice milling unit and the second rice milling unit to form white rice, and be discharged from the other end of the rice milling mechanism.

[0037] In addition, preferably, the first rotary knife comprises:

[0038] a first blade part fixed to the outer wall of the first rotating shaft, and a first scraper part bent from the end of the first blade part and extending along the X direction.

[0039] An angle between an axis of the first scraping portion and the second rotating shaft axis in the X, Y plane forms a first blade angle, the first blade angle ranging from 10° to 20°.

[0040] The second rotating knife includes:

[0041] A second blade portion fixedly formed with an outer wall of the second rotating shaft, and a second scraping portion bent from an end of the second blade portion and extending in the X direction;

[0042] An angle between an axis of the second scraping portion and the second rotating shaft axis in the X, Y plane forms a second blade angle, the second blade angle ranging from 10° to 20°.

[0043] In addition, preferably, the rice mill includes a first bran outlet corresponding to the first rice milling cavity and configured outside the first mesh cage to collect first-class rice bran, and a second bran outlet corresponding to the second rice milling cavity and configured outside the second mesh cage to collect second-class rice bran; the first bran outlet and the second bran outlet are arranged in isolation from each other.

[0044] In addition, preferably, the rice mill includes a box structure, the box structure including a feeding port and a discharging port;

[0045] The feeding port is configured to allow brown rice to enter the rice milling mechanism;

[0046] The discharging port is configured to allow white rice formed after the brown rice is milled by the rice milling mechanism to be discharged;

[0047] The rice mill further includes a drive motor located in the box structure, the drive motor being configured to drive the first rotating shaft and the second rotating shaft to rotate.

[0048] In addition, preferably, the rice mill further includes a fan;

[0049] The fan is configured to allow the brown rice to be conveyed and operated in the rice milling mechanism, and the air power of the fan can strip the rice bran from the brown rice.

[0050] In addition, preferably, the first rotating shaft and the second rotating shaft are fixedly connected at adjacent ends, and the two rotating shafts are synchronously rotated by the same drive motor.

[0051] In addition, preferably, the rice mill includes:

[0052] A first drive motor configured to drive the first rotating shaft to rotate; and

[0053] A second drive motor configured to drive the second rotating shaft to rotate.

[0054] A second drive motor configured to drive the second rotating shaft to rotate.

[0055] The first rotation axis and the second rotation axis have different rotation speeds.

[0056] In addition, preferably, the first mesh cage and the second mesh cage have different mesh sizes.

[0057] In addition, preferably, the mesh size of the second mesh cage is greater than the mesh size of the first mesh cage.

[0058] To achieve the above-mentioned second object, the application discloses a graded rice bran prepared by using the accurate grading processing method.

[0059] In order to make full use of the nutritional components in the rice bran and improve the utilization rate of the rice bran, the obtained graded rice bran can be combined with other substances to obtain various rice bran functional products. For example, the rice bran of different layers can be mixed with wheat flour to prepare rice bran noodles, so as to improve the paste properties of the mixed flour, the cooking loss and the breaking performance of the noodles, etc.

[0060] The beneficial effects of the application are as follows:

[0061] The application discloses an accurate grading processing method and device for rice bran. Since the composition of the rice bran obtained by different means is quite different, the rice bran can only be used as feed in many cases, which causes great waste of resources. The application uses a special rice mill to accurately and flexibly mill brown rice. By setting different rotation angles of the rotary knife, different rotation speeds of the scraper, and cooperating with the wind direction, wind flow and speed of the fan, the rice milling accuracy and the rice bran accuracy can be controlled by multiple parameters, the difference of the component composition in the rice bran of each layer is controlled, the protein, fat, ash content, total starch and DF content of the rice bran present a regular change trend, and conditions for subsequently improving the application value of the rice bran are provided. BRIEF DESCRIPTION OF DRAWINGS

[0062] The specific embodiments of the application will be further described in detail below with reference to the accompanying drawings.

[0063] Figure 1 An overall structure schematic diagram of a rice mill provided by the application is shown.

[0064] Figure 2 An internal structure schematic diagram of the rice mill is shown. Figure 1 An internal structure schematic diagram of the rice mill is shown.

[0065] Figure 3 An internal structure schematic diagram of the rice mill is shown. Figure 1 An internal structure schematic diagram of the rice mill is shown.

[0066] Figure 4 A rotary knife structure perspective view of an embodiment is shown.

[0067] Figure 5A side view of a rotary knife structure of an embodiment is shown. DETAILED DESCRIPTION

[0068] In order to more clearly illustrate the application, the application will be further described below with reference to the preferred embodiments and accompanying drawings. Like reference numerals in the drawings denote like elements throughout. It should be understood by those skilled in the art that the specific description given below is illustrative and not restrictive and is not intended to limit the scope of the application.

[0069] Device Embodiment

[0070] In view of the problems that the rubber roller, iron roller and sand roller are currently used for milling rice bran in multi-machine milling, the rice grain loss is large during milling, the milling is uneven, the rice body temperature rises, the broken rice and crack amount is large, especially the milling degree of rice bran cannot be accurately controlled, and the target rice bran product cannot be obtained, the embodiment provides a rice mill, which is mainly used for processing brown rice, so that each level of target rice bran product can be accurately obtained by only one device. Specifically, in combination with Figures 1 to 5 As shown in the figure, the rice mill comprises a rice milling mechanism, and in combination with the figure, the rice milling mechanism comprises a first rice milling unit 1 and a second rice milling unit 2 arranged along the X direction. Brown rice can enter from one end of the rice milling mechanism, be milled by the first rice milling unit 1 and the second rice milling unit 2 to form white rice, and be discharged from the other end of the rice milling mechanism. The first rice milling unit 1 in the embodiment comprises a first mesh cage with a first rice milling cavity, the axis of which is arranged along the X direction, a first rotating shaft 11 rotatable and arranged along the X direction in the first rice milling cavity, and a first rotary knife 12 fixed to the outer wall of the first rotating shaft 11.

[0071] The second rice milling unit 2 comprises a second mesh cage with a second rice milling cavity, the axis of which is arranged along the X direction, a second rotating shaft 21 rotatable and arranged along the X direction in the second rice milling cavity, and a second rotary knife 22 fixed to the outer wall of the second rotating shaft 21. The first rice milling cavity and the second rice milling cavity are arranged in communication in the X direction.

[0072] In existing technologies, brown rice typically undergoes controlled milling time after entering the milling mechanism to obtain the desired white rice. During the milling process, all the bran that peels off from the surface of the brown rice is mixed together. From the surface of the brown rice inwards, different layers of bran have different nutritional components, and bran with different milling reduction rates contains different nutrients, such as vitamins, dietary fiber, trace elements, polyphenols, and γ-oryzanol. Existing milling mechanisms cannot separate and collect the different layers of bran. Research has found that the angle of the rotary blades affects the shape and depth of the grooves on the surface of the brown rice, which in turn affects the friction and angle of the brown rice on the outer rough mesh. Therefore, unlike existing technologies, the present invention provides a rice milling machine structure in which the first rotary blade 12 configured in the first milling unit 1 and the second rotary blade 22 configured in the second milling unit 2 are respectively set with different blade angles. By designing the angle of the rotary blades, the first rotary blade 12 of the first rice milling unit 1 can perform a first grooving on the surface of the brown rice according to the grooving depth design requirements, and then grind the brown rice with the first mesh cage to obtain the first-grade rice bran. The second rotary blade 22 of the second rice milling unit 2, targeting the brown rice after the first-grade rice bran has been removed, performs a second grooving according to the grooving depth design requirements, and then grinds the brown rice with the second mesh cage to obtain the second-grade rice bran, thereby achieving the invention objective of accurately obtaining target rice bran products of various grades.

[0073] In one embodiment, the first rotary cutter 12 includes: a first blade portion fixed to the outer wall of the first rotating shaft 11, and a first scraper portion bent from the end of the first blade portion and extending in the X direction; the angle between the axis of the first scraper portion and the axis of the first rotating shaft in the X and Y planes forms a first blade angle, the degree range of which is 10° to 20°.

[0074] The second rotary cutter 22 includes: a second blade portion fixed to the outer wall of the second rotating shaft 21, and a second scraper portion bent from the end of the second blade portion and extending along the X direction; the angle between the axis of the second scraper portion and the axis of the second rotating shaft in the X and Y planes forms a second blade angle, the degree range of which is 10° to 20°.

[0075] Combination Figure 4 , 5 As shown, Figure 4 A perspective view of a rotary cutter structure according to one embodiment is shown. Figure 5 A side view of a rotary cutter structure according to one embodiment is shown. It should be noted that the first rotary cutter 12 and the second rotary cutter 22 may have similar structures or different structures. Figure 4 , 5The structure of the rotary knife is only schematically shown and is not intended to limit the structure of the first rotary knife and the structure of the second rotary knife. The first rotary knife 12 is taken as an example for illustration. The first rotary knife 12 includes a first blade portion 121 fixed to the outer wall of the first rotary shaft 11, and a first scraper portion 122 bent from the end of the first blade portion 121 and extending along the X direction. The angle between the axis of the first scraper portion 122 and the axis of the first rotary shaft 11 in the X-Y plane forms a first blade angle θ, and the degree of the first blade angle θ ranges from 10° to 20°.

[0076] In the structure shown in the embodiment, the proximal ends of the first rotary shaft 11 and the second rotary shaft 21 are fixedly connected, and the two rotary shafts are synchronously rotated by the same driving motor. It can also be understood that the first rotary shaft and the second rotary shaft can be the same rotary shaft. The design that the first rotary shaft and the second rotary shaft are the same rotary shaft facilitates the assembly of the rice milling mechanism to some extent, effectively reduces the cost, and the rotation of the first rotary knife and the second rotary knife is more stable, and resonance caused by the rotary motion of the rotary knives does not occur between the two rotary knives.

[0077] In order to collect different levels of target rice bran products with better quality, in an optional embodiment, the rice milling machine includes a first driving motor for driving the first rotary shaft to rotate, and a second driving motor for driving the second rotary shaft to rotate. The first rotary shaft and the second rotary shaft have different rotation speeds. Through the above arrangement, the first rotary knife and the second rotary knife with different blade angles can be configured to have different rotation speeds, so that different levels of target rice bran products with better quality can be obtained in a more accurate manner.

[0078] The different directions, flow rates and speeds of the air flow of the fan directly affect the friction degree and angle of the rough rice on the outer rough mesh cage, and the rough rice milling precision and bran yield precision can be controlled by opening the roughness with the rotary knives with different blade angles, so as to obtain target rice bran products of different levels.

[0079] In the embodiment, the rice milling machine further includes a fan. The fan is configured to convey and transport the rough rice in the rice milling mechanism, and the air flow of the fan can strip the rice bran from the rough rice. Specifically, after the rough rice enters the rice milling mechanism, the rough rice can be conveyed to the second rice milling unit along the first rice milling unit under the action of the air flow of the fan. The rotation of the rotary knife can groove the surface of the rough rice. The fan conveys and applies a forward and outward force to the rough rice at the same time, so that the rough rice can walk and rub on the outer rough mesh cage, and the purpose of milling the rough rice is achieved.

[0080] In combination with Figure 1As shown, in one embodiment, the rice mill comprises a box structure 3, which comprises a feeding port 31 and a discharging port 32. The feeding port 31 is configured to allow the brown rice to enter the rice mill; the discharging port 32 is configured to allow the white rice formed after the brown rice is milled by the rice mill to be discharged; the rice mill further comprises a driving motor 33 located in the box structure, which is configured to drive the first rotating shaft 11 and the second rotating shaft 21 to rotate.

[0081] In order to realize the collection of different levels of rice bran, in combination with the drawings of the present application, in one embodiment, the rice mill comprises a first rice bran outlet 4 corresponding to the first milling cavity and configured outside the first mesh cage to collect the first level of rice bran, and a second rice bran outlet 5 corresponding to the second milling cavity and configured outside the second mesh cage to collect the second level of rice bran; the first rice bran outlet 4 and the second rice bran outlet 5 are arranged separately from each other.

[0082] Optionally, the discharging port 32 is arranged in a slope, the rice bran outlet of the first milling cavity blows out from the first mesh cage in a positive pressure form through a cyclone collector, is connected to the outside world, and a buckle-equipped cylinder port capable of binding a cloth bag is arranged outside the first rice bran outlet 4. Similarly, the rice bran outlet of the second milling cavity blows out from the second mesh cage in a positive pressure form through a cyclone collector, is connected to the outside world, and a buckle-equipped cylinder port capable of binding a cloth bag is arranged outside the second rice bran outlet 5. The rice bran outlet of the first milling cavity and the rice bran outlet of the second milling cavity can be connected to an air compressor and a cold dryer, and clean, dry and low-temperature air continuously enters the rice mill to take away a small amount of temperature generated by the friction of the rice body, so that the temperature of the rice body does not rise but falls, greatly ensuring the quality of the rice and the rice bran.

[0083] In one embodiment, according to different levels of rice bran, the first mesh cage and the second mesh cage also have different structures, specifically, the first mesh cage and the second mesh cage have different mesh sizes. Preferably, the mesh size of the second mesh cage is greater than that of the first mesh cage.

[0084] The present application provides a rice mill that utilizes the stirring of the rotary knife and the air force of the fan to maximize the separation efficiency of the brown rice and the rice bran. In addition, the blade part and the scraper part of the rotary knife can quickly stir the brown rice and the rice bran in the milling cavity of the milling unit. The brown rice can be lifted by the stirring of the rotary knife, at which time the gravity of the brown rice can make the mesh cage of the milling unit fall down, so that the shaking can be generated, which greatly improves the separation efficiency of the brown rice and the rice bran. The separated rice bran is discharged from the mesh cage and collected by the rice bran outlet, which improves the discharge efficiency.

[0085] The following experiments are all carried out by using the above-mentioned rice mill.

[0086] Example 1

[0087] Take 100.00 g of pearl brown rice sample and long grain brown rice sample respectively, and use a rice mill to mill, the parameters of the rice mill are as follows: air speed is 7.6-14.1 m / min, exhaust pressure is 0.75-1.25 Mpa, air inlet angle is 25-30°, cutter angle is 10-20°, and feeding amount is 2 kg / min, the calculation of peeling rate is as follows: the peeling rate of pearl brown rice bran (ZZM-RB) and long grain brown rice bran (CLX-RB) is 0-2%, 2-4%, 4-6%, 6-8%, 8-10%, 10-12%, and 12-14% respectively, the error is within 0.05%, and the samples are crushed through a 60 mesh sieve, packaged in a sealed bag, and placed in a-20℃ refrigerator for standby, the peeling rate results are shown in Table 1. 3

[0088]

[0089] Table 1 Theoretical and actual values of peeling rate

[0090]

[0091] Note: In order to facilitate the discussion of the results, 1 st , 2 nd , 3 rd , 4 th , 5 th , 6 th , 7 th , are represented as different bran layers of rice bran.

[0092] The color difference values of different bran layers of rice bran are shown in Table 2.

[0093] Table 2 Color difference of different bran layers of rice bran

[0094]

[0095] The basic nutritional components of different bran layers of rice bran were determined, wherein the moisture content was determined by GB 5009.3-2016 direct drying method; the protein content was determined by GB 5009.5-2016 combustion method, the fat content was determined by GB 5009.6-2016 Soxhlet extraction method; the ash content was determined by GB 5009.4-2016 determination of total ash in food; the total starch and SDF / IDF were determined by referring to the Megazyme kit method, and the moisture content, protein content, fat content, ash content, total starch content and DF content of different bran layers of rice bran were obtained by taking the average of three sets of parallel data.

[0096] Moisture content of different bran layers of rice bran

[0097] The results are shown in Table 3, and with the increase of brown rice peeling rate, the moisture content of rice bran increases significantly (P<0.05).​st The moisture content of ZZM-RB and CLX-RB is only 10.64% and 9.94%, respectively, while 7 th The moisture content of the rice bran was 11.97% and 10.95%.

[0098] Table 3. Moisture content of rice bran in different bran layers

[0099]

[0100] Protein content of rice bran in different bran layers

[0101] Table 4 shows that the protein content varies among different rice bran varieties, with ZZM-RB having a lower protein content than CLX-RB. As the brown rice peeling rate increases, the protein content of both types of rice bran shows a consistent trend, reaching a certain level at 1... st ~3 rd In rice bran, the protein content shows an increasing trend, compared to 1 st Compared to rice bran, 2 nd ~3 rd The protein content increased by 2.35% and 4.40% in ZZM-RB, respectively, and by 2.62% and 2.90% in CLX-RB, respectively. In 3 rd ~7 th In rice bran, the protein content was significantly reduced (P < 0.05), compared to 3... rd Compared to rice bran, 4 th ~7 th The protein content in ZZM-RB decreased by 5.56%, 14.65%, 21.66%, and 27.30%, respectively, while in CLX-RB it decreased by 6.78%, 11.31%, 19.79%, and 25.09%, respectively. Therefore, 1 st ~3 rd Rice bran has a high protein content, with average contents of 12.89% and 13.43% in ZZM-RB and CLX-RB, respectively, making it suitable for the extraction and application of rice bran protein.

[0102] Table 4. Protein content of rice bran in different bran layers

[0103]

[0104] Different bran layers of rice bran fat content

[0105] Fat is mainly concentrated in the bran layer of brown rice, significantly affecting its appearance and flavor. Table 5 shows that the fat content in rice bran varies among different varieties, with ZZM-RB having a higher fat content than CLX-RB. As the brown rice peeling rate increases, the fat content in the bran of both varieties shows a consistent trend, initially increasing and then decreasing. nd Rice bran has the highest fat content. (Compared to 2) nd Compared to rice bran, 3rd ~7 th The fat content in ZZM-RB was reduced by 14.60%, 27.44%, 42.80%, 57.29%, and 73.33%, respectively, and in CLX-RB was reduced by 8.01%, 30.79%, 49.38%, 59.78%, and 70.02%, respectively. In ZZM-RB, the fat content was reduced from 21.44% to 6.22%, and in CLX-RB, the fat content was reduced from 18.14% to 6.16%. Therefore, 1 st ~3 rd The fat content in rice bran is high, and the average fat content in ZZM-RB and CLX-RB is 20.17% and 17.32%, respectively, so rice bran can be used as the preferred raw material for extracting rice bran oil to realize the value-added utilization of rice bran raw materials.

[0106] Table 5 Fat content of rice bran in different bran layers

[0107]

[0108]

[0109] Ash content of rice bran in different bran layers

[0110] As shown in Table 6, with the increase of the husked rice peeling rate, the ash content in ZZM-RB was significantly reduced (P<0.05) by 2.42%, 17.68%, 36.54%, 45.15%, 60.62%, and 68.46%, respectively. The ash content in CLX-RB first increased and then decreased, and was increased by 2 nd The ash content in rice bran is the highest, 3 rd ~7 th The ash content in rice bran was significantly reduced (P<0.05) by 8.72%, 24.99%, 29.87%, 47.59%, and 56.16%, respectively.

[0111] Table 6 Ash content of rice bran in different bran layers

[0112]

[0113] Total starch content of rice bran in different bran layers

[0114] As shown in Table 7, except for 2 ndIn addition to the rice bran, the content of ZZM-RB starch in the rest of the bran layer was higher than that of CLX-RB. With the increase of the husked rice peeling rate, the total starch content in the two kinds of rice bran showed the same trend, which increased significantly (P<0.05). The total starch content in ZZM-RB increased by 65.28%, 256.02%, 474.22, 657.36%, 829.17%, 909.09%, respectively, and the total starch content in CLX-RB increased by 120.80%, 257.38%, 474.31%, 572.13%, 785.54%, 895.49, respectively. th The total starch content in ZZM-RB and CLX-RB was as high as 63.75% and 58.48%, respectively, which was more than 10 times that of the rice bran. st The color of the rice bran, the extraction and utilization of active substances in the rice bran were affected by the starch content in the rice bran. When the starch content in the rice bran was high, such as the 6th to 7th rice bran, it was not suitable for the extraction of rice bran oil, rice bran protein and other components, and it was more suitable for the development of starch sugar products.

[0115] Table 7 Total starch content of rice bran in different bran layers

[0116]

[0117] DF content of rice bran in different bran layers

[0118] As shown in Table 8, the IDF, SDF and TDF contents of the two kinds of rice bran showed the same trend, which decreased with the increase of the husked rice peeling rate (P<0.05). Taking ZZM-RB as an example, the IDF content decreased by 20.50%, 42.60%, 65.16%, 75.75%, 87.59, 94.63%, respectively, the SDF content decreased by 10.99%, 34.68%, 49.38%, 81.86%, 75.92%, 80.50%, respectively, and the TDF content decreased by 19.26%, 41.56%, 63.09%, 76.55%, 86.06%, 92.77%, respectively. Therefore, the IDF, SDF and TDF contents of the 1 st ~3 rd The DF content in the rice bran was high, which could be used to develop high-DF staple foods and improve the intake of DF to exert its functional characteristics.

[0119] Table 8 DF content of rice bran in different bran layers

[0120]

[0121] Obviously, the above embodiments of the present application are merely exemplary for clearly illustrating the present application, and are not intended to limit the implementation modes of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art, and here, all the implementation modes cannot be exhausted, and any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.

Claims

1. A precision fractionation process of rice bran, characterized by, The precision grading processing method comprises the following steps: 1) brown rice is polished by a rice polisher to control the husking rate to be 0-2%, and the husking rate is not 0, to obtain 1 st rice bran and 1 st brown rice; 2) 1 st The brown rice was milled by a rice mill to control the husking rate at 2-4%, to obtain 2 nd Rice bran and 2 nd Brown rice; 3) 2 nd Rice is milled by a rice mill to control the husking rate to 4-6%, and 3 rd Rice bran and 3 rd Rice; 4) 3 rd Brown rice was milled by a rice mill to control the husking rate at 6-8%, and 4 th Rice bran and 4 th Brown rice; 5) 4 th The brown rice was milled by a rice mill to control the husking rate at 8-10%, and 5 th rice bran and 5 th brown rice; 6) 5 th The brown rice was milled by a rice mill to control the husking rate at 10-12%, and 6 th Rice bran and 6 th Brown rice; 7) 6 th The brown rice was milled by a rice mill to control the husking rate at 12-14%, and 7 th Rice bran and 7 th Brown rice; 8) Collecting the rice bran of each bran layer respectively, and then performing a stabilization treatment on the rice bran of each bran layer; The rice mill control parameters are: air speed is 7.6-14.1 m 3 / min, exhaust pressure is 0.75-1.25 Mpa, air inlet angle is 25-30°, cutter angle is 10-20°, and feeding amount is 2 kg / min. The 1 st Rice bran, 2 nd Rice bran and 3 rd The fat content of rice bran is ≥ 16.5%, the protein content is ≥ 12.5%, the ash content is ≥ 8.5%, the dietary fiber is ≥ 23%, and the starch content is ≤ 22.5%; The 4 th Rice bran, 5 th Rice bran and 6 th The fat content of rice bran is ≥7.2%, the protein content is ≥10.3%, the ash content is ≥4.3%, the dietary fiber is ≥5.5%, and the starch content is ≤58.7%. The 7 th Rice bran with a fat content of > 6.1 %, a protein content of > 9.5 %, an ash content of > 3.4 %, a dietary fiber content of > 2.8 %, and a starch content of < 63.8 %; The rice mill comprises a rice milling mechanism, and the rice milling mechanism comprises at least a first rice milling unit and a second rice milling unit arranged along the X direction; The first rice milling unit comprises: a first screen cage with a first rice milling cavity; a first rotating shaft rotatable in the first rice milling cavity; and a first rotary knife fixed to the outer wall of the first rotating shaft; The second rice milling unit comprises: a second screen cage with a second rice milling cavity; a second rotating shaft rotatable in the second rice milling cavity; and a second rotary knife fixed to the outer wall of the second rotating shaft; The first rice milling cavity and the second rice milling cavity are arranged in communication in the X direction; The first rotary knife and the second rotary knife have different blade angles; Rough rice can enter from one end of the rice milling mechanism, be milled by the first rice milling unit and the second rice milling unit to form white rice, and be discharged from the other end of the rice milling mechanism; The first rotary knife comprises: a first blade part fixed to the outer wall of the first rotating shaft, and a first scraper part bent from the end of the first blade part and extending along the X direction; The angle between the axis of the first scraper part and the axis of the first rotating shaft in the X, Y plane forms a first blade angle, and the degree of the first blade angle ranges from 10° to 20°; The second rotary knife comprises: a second blade part fixed to the outer wall of the second rotating shaft, and a second scraper part bent from the end of the second blade part and extending along the X direction; The angle between the axis of the second scraper part and the axis of the second rotating shaft in the X, Y plane forms a second blade angle, and the degree of the second blade angle ranges from 10° to 20°.

2. The precision fractional machining method according to claim 1, characterized in that, The stabilization treatment comprises one or more of a dry heat method, an extrusion puffing treatment, a microwave heating treatment, a superheated steam treatment, a non-thermal stabilization method, a chemical reagent stabilization method, and a biological stabilization method.

3. The precision fractional machining method according to claim 1, characterized in that, The rice mill comprises a first bran outlet corresponding to the first rice milling cavity and arranged outside the first screen cage to collect first-stage rice bran, and a second bran outlet corresponding to the second rice milling cavity and arranged outside the second screen cage to collect second-stage rice bran; The first bran outlet and the second bran outlet are arranged in isolation from each other.

4. The precision fractional machining method of claim 1, wherein, The rice mill comprises a box structure, and the box structure comprises a feeding port and a discharging port; The feeding port is configured to allow rough rice to enter the rice milling mechanism; The discharging port is configured to allow white rice formed after rough rice is milled by the rice milling mechanism to be discharged; The rice mill further comprises a drive motor arranged in the box structure, and the drive motor is configured to drive the first rotating shaft and the second rotating shaft to rotate. The rice mill further comprises a fan; 5. The precision fractional machining method of claim 1, wherein, The fan is configured to allow rough rice to be transported and operated in the rice milling mechanism, and the air power of the fan can strip rice bran from the rough rice. The adjacent ends of the first rotating shaft and the second rotating shaft are fixedly connected, and the two rotating shafts are synchronously rotated by the same drive motor.

6. The precision fractional machining method of claim 1, wherein, The rice mill comprises:

7. The precision fractional machining method of claim 1, wherein, a first drive motor configured to drive the first rotating shaft to rotate; and a second drive motor configured to drive the second rotating shaft to rotate; The first rotating shaft and the second rotating shaft have different rotating speeds. ​ 8. The precision fractional machining method of claim 1, wherein, The first mesh cage has a different mesh size than the second mesh cage.

9. The precision fractional machining method of claim 1, wherein, The second mesh cage has a larger mesh size than the first mesh cage.

10. Fractionated rice bran produced by the precision fractionation process of any one of claims 1-9.

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