Processing method for reducing broken rice rate of commercial rice

Abstract

The invention discloses a processing method for reducing the broken rice rate of commercial rice, which comprises the following steps: S1, an unhulled rice pretreatment stage: S1a, a multi-stage linkage impurity removal process is adopted, and large impurities, light impurities, metal impurities and stones in unhulled rice are removed through combination of classified screening, airflow separation, magnetic separation and specific gravity stone removal, so that the impurity removal rate is greater than or equal to 99%; s1b, on the basis of a dynamic adaptation model of rice physical characteristics and rice hulling parameters, rice moisture and hardness data are collected in real time through a first detection device, the rice hulling flow and the inter-roller pressure are calculated and adjusted through a control unit, and closed-loop control is achieved; s2, carrying out a color sorting and polishing stage; s3, carrying out a rice milling regulation and control stage; and S4, entering a vacuum packaging stage.

Description

Technical Field

[0001] This application relates to the field of rice processing technology, and more specifically, to a processing method for reducing the broken rice rate of commercial rice. Background Technology

[0002] As consumers' living standards improve, their demands for rice quality have shifted from simply "filling their stomachs" to "high quality." They now focus not only on the integrity of the rice grains (broken rice rate) but also on appearance, color, nutrient retention (such as trace elements like zinc and selenium), and freshness. Traditional rice processing methods face numerous technical bottlenecks: In the pre-treatment stage, conventional screening, air separation, and magnetic separation technologies have limited effectiveness in removing impurities (stones, metals, chaff, etc.), failing to meet the quality requirements of high-end commercial rice; the hulling stage uses fixed parameters to process different varieties of rice, making it impossible to dynamically adjust process parameters based on the rice's moisture content, hardness, and other physical characteristics, resulting in a persistently high brown rice breakage rate; in the color sorting and polishing stage, traditional optical recognition is insufficiently accurate, making it difficult to precisely remove discolored grains, and the polishing process easily leads to the loss of trace elements; the milling stage lacks real-time monitoring and control methods, making the bran outlet channel prone to blockage and resulting in inaccurate control of the bran retention rate; and outdated preservation technologies in the packaging stage affect the shelf life of the finished rice. These problems collectively lead to excessive broken rice rates and unstable quality in commercial rice, hindering the market competitiveness of high-end rice. To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a prefabricated wall fixing device and assembly method that is simple in structure, reliable in connection, and convenient in construction.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A processing method for reducing the broken rice rate of commercial rice includes the following steps: S1. Rice pretreatment stage: S1a. A multi-stage linkage impurity removal process is adopted, which removes large impurities, light impurities, metallic impurities and stones from rice through a combination of graded screening, airflow separation, magnetic separation and gravity destoning, so that the impurity removal rate is ≥99%; S1b. Based on the dynamic adaptation model of rice physical properties and hulling parameters, the first detection device collects rice moisture and hardness data in real time, and the control unit calculates and adjusts the hulling flow rate and roller pressure to achieve closed-loop control. S2. Color sorting and polishing stage; S3. Rice milling control stage; S4. Vacuum packaging stage.

[0005] Furthermore, this application also proposes that, in step S1a, the screening stage adopts a three-layer grading screen with screen apertures of 4.0-5.0mm, 2.5-3.0mm, and 1.2-1.8mm, a screen tilt angle of 12°-20°, and a vibration frequency of 45-55Hz; the air separation stage adopts a counter-current air separator with an air velocity of 3.0-3.8m / s; the magnetic separation stage is equipped with at least one strong magnetic separator with a magnetic field strength of 7000-12000Gs; and the destoning stage adopts a gravity destoner with an air volume of 1500-2200m³ / h and an amplitude of 2-6mm.

[0006] Furthermore, this application also proposes that the first detection device for the dynamic adaptation model in step S1b is a near-infrared spectrometer or a microwave moisture and hardness meter.

[0007] Furthermore, this application also proposes that the control unit has a built-in dynamic adaptation model: rice hulling flow rate Q = 16 - 0.5 × M, where M is the rice moisture content, 12% ≤ M ≤ 16%; roller pressure P = 0.06 - 0.1 × H, where H is the rice hardness, 6 kgf ≤ H ≤ 9 kgf; the actuator adjusts the feeding speed through a hydraulic cylinder and adjusts the roller pressure through a hydraulic system.

[0008] Furthermore, this application also proposes that, in step S2, the color sorting and polishing stage includes: S2a. Using a screening structure adapted to rice grain shape in conjunction with an optical recognition device to remove discolored grains and defective grains, with a discolored grain removal rate ≥98%; S2b. Using a misting water synergistic polishing process, combined with ultraviolet sterilization treatment, to perform polishing treatment.

[0009] Furthermore, this application also proposes that the screening structure in step S2a is a customized mesh screen with a screen aperture size adapted to the target rice grain shape, and the optical recognition device is a CCD camera with a resolution ≥1920×1080, a recognition wavelength range of 380-720nm, and focuses on identifying mold spots with a gray value ≤55 and discolored grains with RGB values ​​satisfying R≥190, ​​G≥170, and B≤160.

[0010] Furthermore, this application proposes that, in step S2b, the whiteness of rice grains and the retention rate of trace elements are balanced by adjusting the atomized water volume, polishing speed, and ultraviolet irradiation parameters; the atomized water-co-polishing process uses an ultrasonic atomizer with atomized particle diameter of 3-12 μm, a water temperature of 22-28℃, and a water volume of 0.4-0.6% of the rice weight; the polishing wheel adopts 2-4 stage speed control with a speed range of 700-1100 r / min; the ultraviolet irradiation wavelength is 240-260 nm, the irradiation intensity is 250-350 μW / cm², and the time is 4-10 s, and the irradiation parameters are dynamically adjusted according to the surface humidity of the rice grains.

[0011] Furthermore, this application also proposes that the steps in step S3, which involve the rice milling control stage, include: S3a. Real-time monitoring of particle size, moisture content, and bran outlet pressure parameters during the rice milling process using a second detection device; S3b. Predicting blockages and performing graded cleaning based on the trend of bran outlet pressure changes, and adjusting the bran retention rate in conjunction with the multi-stage rice milling process.

[0012] Furthermore, this application also proposes that the second detection device in step S3a includes a laser particle size sensor, a near-infrared moisture meter, and a pressure sensor; the grading cleaning in step S3b includes at least two combinations of high-frequency vibration cleaning, airflow cleaning, speed regulation cleaning, and ultrasonic cleaning, and the multi-stage rice milling process involves 2-4 layers of rice milling.

[0013] Furthermore, this application also proposes that the vacuum packaging step S4 includes: S4a. using a high-barrier composite packaging material, which has oxygen barrier and moisture barrier properties; S4b. using a vacuum packaging process for packaging.

[0014] Compared with existing technologies, this application provides a processing method for reducing the broken rice rate of commercial rice. Through a dynamic adaptation model, it achieves precise parameter control, effectively reducing the broken rice rate and improving quality stability.

[0015] In a further embodiment, the combination of atomized polishing and real-time monitoring technology has the advantages of improving impurity removal efficiency, reducing the breakage rate of brown rice processing, and improving the quality stability of finished rice. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the rice huller control system of the present invention. Detailed Implementation

[0017] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0018] In existing technologies, traditional rice processing techniques suffer from incomplete impurity removal and fixed hulling parameters. Impurities such as stones, metal fragments, and shriveled grains mixed in with the rice raw material are difficult to completely remove through simple screening or air separation alone. These residual impurities exacerbate mechanical friction during subsequent processing, leading to rice grain breakage. The fixed flow rate and roller pressure parameters used in the hulling stage cannot adapt to the differences in hardness and moisture content among different rice varieties, causing the expansion of surface cracks in the brown rice and a significant increase in broken rice during milling. As the market demands higher rice integrity, existing processes are no longer sufficient to meet the processing requirements of low broken rice rates and high nutrient retention.

[0019] To address these issues, researchers discovered that the static parameter settings in traditional processes are a key factor leading to high broken rice rates. Analysis revealed that differences in the physical properties of paddy directly affect the optimal operating state of the rice hulling equipment, while the amount of residual impurities influences the probability of mechanical damage during the milling stage. Based on this, a multi-stage, interconnected impurity removal system was proposed to eliminate impurity interference, while a dynamic parameter adjustment mechanism was introduced to adapt the rice hulling process to the characteristics of the raw materials. Furthermore, considering the continuity of processing, subsequent color sorting, milling, and packaging processes were incorporated into the overall control system, forming a complete chain for preventing broken rice throughout the entire process. Therefore, this application proposes a method for processing commercial rice to reduce the broken rice rate, comprising the following steps: S1, Rice pretreatment stage; S2, color sorting and polishing stage; S3, the rice milling control stage; and S4, processing method for the vacuum packaging stage.

[0020] Specifically, in step S1, the rice pretreatment stage includes: S1a employs a multi-stage linkage impurity removal process combining graded screening, airflow separation, magnetic separation, and gravity destoning. S1b collects real-time data on rice moisture and hardness through the first detection device, and the control unit calculates and adjusts the rice hulling flow rate and roller pressure. The multi-stage linkage impurity removal process refers to the coordinated operation of impurity separation equipment based on different physical principles. Grading and screening remove large particles with significant size differences; airflow separation separates light impurities based on differences in material suspension velocity; magnetic separation adsorbs metallic impurities using a magnetic field; and gravity separation separates stones based on density differences. The dynamic adaptation model establishes a mathematical relationship between the operating parameters of the rice hulling equipment based on data on rice moisture content and hardness. Moisture affects rice brittleness, and hardness determines the required roller pressing strength; the model calculates and dynamically matches these parameters. The first detection device acquires rice grain properties in real time, using non-contact measurement with spectral or microwave sensing technology. The control unit adjusts the feed speed and roller spacing through the actuator, forming a closed-loop feedback system. Specifically, in the rice pretreatment stage, impurities are first removed through a multi-stage linkage impurity removal process. Grading screening removes large particles such as straw and gravel by particle size, airflow separation removes light impurities such as chaff and dust, magnetic separation adsorbs metals such as iron filings, and gravity separation separates denser stones.

[0021] like Figure 1 As shown, a dynamic adjustment system suitable for rice hullers is presented, specifically including: a first detection device 11, a control unit 12, and an actuator 13. The detection device 11 can detect at least the moisture content and hardness of the rice, and the actuator 13 includes at least a feeding speed adjustment mechanism 131 and a roller spacing adjustment mechanism 132. After impurity removal, the first detection device performs online detection of the rice moisture and hardness. After the data is input into the control unit, the dynamic adaptation model automatically calculates the appropriate hulling flow rate and roller pressure for the current rice. The flow rate is adjusted inversely according to the moisture content; when the moisture content is high, the flow rate is reduced to avoid rice grain sticking and breakage. The roller pressure is adjusted in the forward direction according to the hardness; when the hardness is high, the pressure is increased to ensure dehulling efficiency. The adjusted parameters are applied to the rice hulling equipment in real time, forming a continuously optimized processing state. Subsequent color sorting and polishing stages use optical sorting to remove defective grains, the rice milling control stage monitors the milling pressure to prevent over-milling, and the vacuum packaging stage inhibits oxidation, all working together to maintain the structural integrity of the rice grains. Compared to existing technologies, traditional processes using fixed screen apertures and air separation parameters cannot effectively handle impurities with complex particle size distributions, and the rice hulling equipment is often in a suboptimal operating state. This solution achieves precise impurity separation through the coordinated configuration of multi-stage impurity removal equipment and overcomes the limitations of fixed parameters through dynamic adjustment driven by physical property data. In existing technologies, the rice hulling stage operates in isolation from subsequent processes, while this solution constructs a fully coordinated control system from front-end impurity removal to final packaging. Through the above technical solutions, this application achieves efficient removal of impurities and dynamic optimization of equipment parameters during rice processing. The multi-stage linkage impurity removal process significantly reduces the interference of residual impurities on subsequent processes, and the dynamic adaptation model ensures that the rice hulling process always matches the characteristics of the raw materials, thereby reducing rice grain breakage caused by mechanical impact. The whole-process collaborative control effectively suppresses factors that generate broken rice at each stage, ultimately improving the integrity and quality stability of the finished rice.

[0022] In this embodiment, during the rice pretreatment stage, a three-layer grading sieve is used in the screening stage, with sieve mesh sizes of 4.0-5.0 mm, 2.5-3.0 mm, and 1.2-1.8 mm, sieve tilt angle of 12°-20°, and vibration frequency of 45-55 Hz; a counter-current air separator is used in the air separation stage, with an air speed of 3.0-3.8 m / s; at least one strong magnetic separator with a magnetic field strength of 7000-12000 Gauss is set in the magnetic separation stage; and a gravity destoner is used in the destoning stage, with an air volume of 1500-2200 cubic meters / hour and an amplitude of 2-6 mm.

[0023] Among them, the three-layer grading screen refers to a multi-layer vibrating screening device with screens of different aperture sizes, specifically a vibrating screen with a stepped aperture distribution, intercepting impurities of different sizes step by step. The counter-current air separator is a separation device where the airflow direction is opposite to the material's falling direction, specifically a combination of a centrifugal fan with adjustable wind speed and a guide plate, effectively separating light impurities through reverse airflow. The high-intensity magnetic separator is a metal adsorption device with a high-intensity magnetic field, specifically a composite magnetic separation structure of permanent magnets and electromagnetic coils, capturing tiny metal impurities through a high-gradient magnetic field. The gravity destoner is a device that separates materials based on density differences, specifically using a mechanism of vibrating screen plates and airflow backflushing working in tandem, optimizing stone separation by adjusting the vibration amplitude and airflow intensity. Specifically, the three-layer grading screen with its gradient aperture design can cover the interception needs of impurities of different sizes in the rice. Large-aperture screens remove large impurities such as straw and large stones; medium-aperture screens intercept medium-sized debris; and small-aperture screens filter fine sand and gravel, while retaining plump rice grains and removing shriveled grains. The coordination of the screen tilt angle and vibration frequency optimizes the material's residence time on the screen surface, preventing screen clogging and improving screening efficiency. The counter-current air separator uses reverse airflow to blow light impurities away from the rice stream; the wind speed control range balances impurity separation efficiency and rice loss rate. The high-intensity magnetic field of the strong magnetic separator thoroughly adsorbs magnetic impurities such as iron filings and metal fragments mixed in the rice. The gravity destoner uses the synergistic effect of vibration and airflow to achieve precise separation by utilizing the density difference between rice and stones; the combination of amplitude and airflow adjustment can adapt to the processing needs of rice with different moisture contents.

[0024] Compared to existing technologies, traditional screening processes often employ single-layer screens or simple two-stage screening, which cannot effectively cover impurities across the entire size range. Furthermore, the fixed screen inclination angle and vibration parameters result in low screening efficiency. Conventional air separation equipment typically uses a co-current design, leading to incomplete separation of light impurities and the loss of paddy grains with the airflow. Ordinary magnetic separators have insufficient magnetic field strength, making it difficult to remove tiny metallic impurities. Traditional destoning equipment relies solely on vibration or airflow, resulting in limited stone separation accuracy. This solution, through the synergistic effect of multi-stage screening and composite sorting equipment, combined with optimized combinations of key process parameters, achieves a significant improvement in impurity removal efficiency, reaching up to 99%.

[0025] Through the above technical solutions, this application can effectively remove impurities with different physical properties from rice, including large-sized foreign objects, light debris, shriveled grains, metallic impurities, and stones, solving the problem of insufficient impurity removal rate in traditional processes. The stepped screening of the three-layer grading screen reduces the probability of screen clogging; the counter-current air separation ensures efficient impurity separation while reducing rice loss; the strong magnetic separator improves the removal capacity of metallic impurities; and the gravity destoner improves stone separation accuracy through the synergistic effect of vibration and airflow. The optimized combination of process parameters at each stage makes the impurity removal process more stable and reliable, providing a higher quality raw material guarantee for subsequent processing stages.

[0026] In this embodiment, in step S1, the first detection device for the dynamic adaptation model in the rice pretreatment stage is a near-infrared spectrometer or a microwave moisture and hardness meter.

[0027] Among them, the near-infrared spectroscopy analyzer is an instrument that analyzes materials by detecting the characteristic spectra generated by the vibration of rice molecules. Specifically, it can be implemented using a device equipped with a diffuse reflection probe and a spectral analysis module. This device continuously collects spectral data from the surface and interior of rice grains in a non-contact manner, and achieves simultaneous detection of two parameters by combining a preset rice moisture and hardness calibration model. The microwave moisture and hardness meter is a primary detection device that utilizes the interaction between microwaves and the dielectric properties of rice. Specifically, it can be implemented using a combination of a multi-band microwave transmitting and receiving system and a dielectric constant analysis module. This device simultaneously analyzes the deep moisture content and hardness index of rice grains by analyzing the phase attenuation and energy loss data generated when microwaves penetrate the rice grains. These two primary detection devices obtain the core physical characteristics of rice grains in real time through non-destructive testing methods, providing fundamental data support for subsequent dynamic parameter adjustments.

[0028] Specifically, the near-infrared spectrometer collects the reflectance spectrum of rice in the near-infrared band using optical sensors. After extracting spectral features, it matches the data with a pre-established rice moisture-hardness database to output real-time detection values. The microwave moisture and hardness meter transmits microwave signals of a specific frequency through the rice pile. Based on the phase change and energy attenuation of the microwave signal received at the receiving end, combined with a model of the correspondence between the dielectric constant and physical properties of rice, it simultaneously calculates the moisture content and hardness values. Both detection methods can perform real-time measurements during the continuous transport of rice, avoiding process interruptions and sample damage caused by traditional sampling and testing, and ensuring that the detection data remains synchronized with the physical properties of the rice actually processed on the processing line.

[0029] Compared to existing technologies, traditional rice hulling processes often employ offline sampling and testing or single-parameter primary detection devices, which suffer from problems such as significant detection lag, damage to sample integrity, and inability to simultaneously acquire moisture and hardness data. In contrast, the primary detection device used in this solution employs non-contact continuous detection, achieving simultaneous measurement of two parameters while maintaining the integrity of the rice grains. This significantly improves the real-time performance and accuracy of the detection data, providing a reliable basis for dynamically adjusting rice hulling parameters.

[0030] Through the above technical solution, this application realizes online non-destructive testing of the physical properties of rice, effectively solving the problem of parameter setting deviations in rice hulling caused by the poor adaptability of traditional testing methods. The real-time and completeness of the test data ensures precise control of rice hulling flow and roller pressure, thereby reducing the risk of mechanical damage during brown rice processing and avoiding production interruptions and material losses caused by sampling and testing.

[0031] In this embodiment, the control unit can be implemented by a PLC controller. The control unit has a built-in dynamic adaptation model. The rice hulling flow rate Q = 16 - 0.5 × M, where M is the rice moisture content and 12% ≤ M ≤ 16%; the roller pressure P = 0.06 - 0.1 × H, where H is the rice hardness and 6 kgf ≤ H ≤ 9 kgf; the actuator adjusts the feeding speed through a hydraulic cylinder and adjusts the roller pressure through a hydraulic system.

[0032] The dynamic adaptation model in this application is based on several years of measured data of 10 mainstream rice varieties in Danzhai County, Qiandongnan Prefecture, Guizhou Province (such as the Danzhai selenium-rich rice variety "Qianxi Rice No. 1" and the fragrant rice variety "Danxiang Rice No. 1"). When M increases by 0.5%, Q decreases by 2t / h to avoid compression damage caused by poor flowability of high-moisture rice. For example, when the hardness of "Qianxi Rice No. 1" is 8.0kgf, P=0.52MPa, and when the hardness of "Danxiang Rice No. 1" is 6.8kgf, P=0.42MPa. By adjusting the pressure between the rollers, the compression resistance of different varieties is precisely matched, thereby reducing the broken rice rate.

[0033] The dynamic adaptation model refers to the mathematical relationship model that transforms rice moisture and hardness parameters into hulling flow rate and roller pressure. Specifically, it can be implemented using linear equations, automatically calculating processing parameters by real-time detection of rice physical properties. Hulling flow rate Q = 16 - 0.5 × M refers to dynamically adjusting the processing volume per unit time based on rice moisture content; reducing the flow rate when moisture content is high to prevent rice grain breakage under pressure. Roller pressure P = 0.06 - 0.1 × H refers to adjusting the hulling pressure based on rice hardness; increasing the pressure when hardness is high to ensure hulling efficiency. The hydraulic cylinder is an actuator that adjusts the feeding speed by changing the power supply frequency, while the hydraulic system controls the roller spacing through oil pressure changes. Both work together to achieve dynamic parameter adjustment. Of course, the hydraulic cylinder is not the only way to adjust the feeding speed; the feeding speed can also be adjusted by changing the size of the feed inlet, or by adjusting the transmission ratio to achieve multi-speed feeding.

[0034] Specifically, after the moisture and hardness data of the paddy rice are collected in real time by the first detection device, the control unit calculates the corresponding hulling flow rate and roller pressure according to a preset formula. When the moisture content of the paddy rice increases, the flow rate decreases linearly to prevent excessive moisture from causing the rice grains to stick together and break. When the hardness of the paddy rice increases, the roller pressure increases proportionally to ensure hulling efficiency while avoiding repeated crushing caused by insufficient pressure. The hydraulic cylinder in the actuator adjusts the feed speed to match the flow rate changes, and the hydraulic system corrects the roller spacing in real time through pressure sensor feedback, forming a closed-loop control mechanism, further reducing the brown rice breakage rate by 40% (from 1.5% to below 0.9%). Compared with existing technologies, as shown in Table 1, traditional rice hulling processes use fixed flow rates and roller pressing parameters, which cannot adapt to the differences in moisture and hardness among different rice varieties. This solution establishes a mathematical model of physical properties and processing parameters to achieve dynamic adaptation of processing parameters. Existing technologies suffer from lag in manual parameter adjustments, while this solution uses an automated control unit to respond in real-time to changes in rice characteristics, eliminating the problem of brown rice breakage caused by parameter mismatch.

[0035] Table 1 Through the above technical solution, this application solves the problem that traditional rice hulling processes, with their fixed parameter settings, cannot adapt to changes in the physical properties of paddy rice. By dynamically adjusting the hulling flow rate and roller pressure, it effectively reduces crushing caused by excessive moisture and over-milling due to insufficient hardness, significantly reducing the brown rice breakage rate. The automated control mechanism avoids human intervention errors, ensuring real-time matching of processing parameters with paddy rice characteristics and improving the stability of processing quality.

[0036] In this embodiment, step S2, the color sorting and polishing stage includes: S2a employs a screening structure adapted to rice grain shape, combined with an optical recognition device, to remove discolored and defective grains. S2b is polished using a combination of atomized water polishing and ultraviolet sterilization. The rice grain-adaptive screening structure refers to a physical screening device with sieve aperture sizes designed according to the geometry of the target rice grains. This can be achieved using customized mesh sieves whose aperture sizes match the rice grain shape, used for the initial separation of discolored and defective grains. The optical recognition device refers to a device that analyzes the surface features of rice grains through optical imaging. This can be achieved using a high-resolution CCD camera, capturing differences in color and texture on the rice grain surface to identify discolored and defective grains. The atomized water-co-polishing process refers to a processing method that uniformly sprays water mist onto the polishing area to form a protective layer. This can be achieved using an ultrasonic atomizer, controlling the diameter of the atomized particles and the amount of water to reduce mechanical friction damage during polishing. The ultraviolet sterilization treatment refers to a sterilization method that uses ultraviolet light of a specific wavelength to irradiate the surface of the rice grains. This can be achieved using ultraviolet lamps, adjusting the irradiation intensity and time to inactivate microorganisms. Specifically, in the color sorting and polishing stage, the rice grains are first physically sorted using a screening structure adapted to the grain shape, removing abnormally sized, discolored, and defective grains. Subsequently, an optical recognition device scans each grain individually, further eliminating discolored grains not removed by physical sorting based on color and surface feature differences. During the polishing process, atomized water is evenly sprayed onto the polishing area, forming a continuous water film on the rice grain surface to reduce the contact pressure between the polishing wheel and the grains, thereby minimizing surface damage. Simultaneously, ultraviolet lamps irradiate the polished rice grains, sterilizing them by disrupting the DNA structure of microorganisms, avoiding the nutrient loss caused by traditional high-temperature sterilization. Compared with existing technologies, traditional methods typically employ fixed-aperture screens and single optical recognition technology, which suffer from problems such as missed screening of discolored particles and insufficient recognition accuracy. The polishing process often relies on mechanical friction and high-temperature treatment, which can easily cause surface damage to rice grains and loss of trace elements. This application improves the removal accuracy of discolored particles through the synergistic effect of physical screening and optical recognition. Simultaneously, it utilizes atomized water to reduce polishing damage and incorporates ultraviolet sterilization to replace high-temperature treatment, forming a multi-protection mechanism. Through the above technical solution, this application can effectively improve the removal rate of discolored and defective grains, reduce mechanical damage to the surface of rice grains during polishing, and retain trace elements in rice grains while achieving sterilization, thus solving the technical contradiction between polishing damage and nutrient loss in traditional processes.

[0037] In this embodiment, step S2a employs a technical solution where a customized screen and a high-resolution optical recognition device work together in the color sorting and polishing stage. The customized screen refers to a physical screening structure where the shape and size of the screen openings are dynamically adjusted according to the grain shape of the target rice grains. Specifically, it can be achieved using CNC punching technology combined with a rice grain morphology database to generate suitable screen openings, thus avoiding mechanical crushing caused by mismatch between the opening diameter and the rice grain size during the screening process. The optical recognition device refers to a high-precision image acquisition system covering the entire visible light spectrum. Specifically, it can be achieved using an industrial-grade CCD camera (optical recognition device with a resolution ≥1920×1080) combined with a multispectral light source (380-720nm), capturing differences in grayscale and RGB color gamut characteristics on the rice grain surface to identify mold and discoloration defects. The mold spot identification standard with a grayscale value ≤55 refers to a quantization threshold established based on the color depth of the moldy area. Specifically, it can be achieved by extracting pixel values ​​from dark spot areas using image processing algorithms, used to distinguish normal rice grains from moldy areas. The RGB value requirement of R≥190, ​​G≥170, B≤160 for identifying discolored grains refers to a combination of color difference thresholds established for the oxidation and yellowing phenomenon. Specifically, it can be achieved through color space conversion and multi-channel threshold segmentation, and is used to detect abnormal color changes on the surface of rice grains.

[0038] Specifically, in the screening stage, a customized mesh screen dynamically matches the aspect ratio and thickness distribution characteristics of rice grains to achieve an optimal fit between the screen aperture ratio and the projected area of ​​the rice grains. This removes impurities while avoiding shear stress on intact rice grains. In the optical identification stage, a CCD camera acquires images of the rice grain surface across the entire visible light spectrum. A grayscale thresholding algorithm identifies dark-colored moldy areas, while RGB three-channel color difference analysis identifies abnormally yellowed particles. The synergistic effect of these two identification modes covers various types of discolored defects such as mold, oxidation, and lesions, and the optimization of the physical screening and optical sorting process reduces the number of repetitive mechanical processing steps.

[0039] Compared to existing technologies, traditional color sorting processes use fixed-aperture screens, which cannot adapt to the morphological differences of different rice varieties, easily leading to an increased rate of broken rice during the sorting process. Furthermore, single-wavelength or monochromatic optical recognition modes struggle to distinguish complex color defects, resulting in a high rate of missed detections of discolored grains. This solution, through the synergistic optimization of physical sorting structures and optical recognition parameters, improves the detection accuracy of discolored defects while reducing the risk of mechanical damage.

[0040] Through the above technical solutions, this application can effectively reduce the mechanical damage to whole rice grains during the screening process, and keep the broken rice rate within the range required by the process; at the same time, it can accurately separate discolored grains and defective grains through dual optical recognition standards, so that the appearance quality of the finished rice reaches the standard of high-end commercial rice.

[0041] In this embodiment, in step S2b, a technical solution is used to balance the whiteness of rice grains and the retention rate of trace elements by adjusting the atomized water volume, polishing speed and ultraviolet irradiation parameters. The atomized water co-polishing process uses an ultrasonic atomizer to generate water mist particles of a specific size, controls the water temperature and water volume ratio, uses segmented speed control for the polishing wheel, and dynamically adjusts the ultraviolet irradiation parameters according to the surface humidity of the rice grains.

[0042] Among these features, the ultrasonic atomizer is a device that converts liquid water into micron-sized atomized particles. Specifically, a piezoelectric ceramic transducer can be used to achieve high-frequency vibration and droplet breakage. The uniform water film generated by this device reduces mechanical damage to the rice grain surface caused by polishing friction. Segmented speed control divides the polishing wheel's operation into multiple speed ranges, which can be achieved by switching speeds using a hydraulic cylinder. This method removes rice bran powder while avoiding the impact force from high-speed rotation that could break the rice grains. Dynamic adjustment of ultraviolet irradiation parameters automatically adjusts the irradiation intensity and time based on real-time changes in the moisture content of the rice grain surface. This can be achieved by linking a humidity sensor with a controller. This mechanism eliminates the problem of incomplete sterilization or over-irradiation caused by differences in the moisture content of the rice grains after polishing. Specifically, the atomized water co-polishing process uses an ultrasonic atomizer with atomized particle diameter of 3-12μm, a water temperature of 22-28℃, and a water volume of 0.4-0.6% of the rice weight; the polishing wheel uses 2-4 stage speed control with a speed range of 700-1100r / min; the ultraviolet irradiation wavelength is 240-260nm, the irradiation intensity is 250-350μW / cm², and the time is 4-10s, and the irradiation parameters are dynamically adjusted according to the surface humidity of the rice grains.

[0043] Specifically, in the polishing process, the water mist generated by the ultrasonic atomizer evenly adheres to the surface of the rice grains, forming a lubricating layer. Combined with segmented speed control, the polishing wheel initially removes loose rice bran powder at a lower speed, then the speed is increased to complete fine polishing. The ultraviolet irradiation device, based on online monitoring of rice grain moisture data, increases the irradiation intensity when humidity is high to penetrate the water film, and extends the irradiation time when humidity is low to ensure sterilization effectiveness. This collaborative control mode maintains the smoothness of the rice grain surface while avoiding the problems of trace element loss or inadequate sterilization caused by fixed parameter settings in traditional processes.

[0044] Compared to existing technologies, traditional polishing processes use fixed water volume and rotation speed parameters, which cannot adapt to the differences in hardness among different rice varieties and can easily cause over-polishing and damage to the endosperm layer. Existing ultraviolet sterilization equipment generally uses a constant irradiation mode, failing to consider the impact of post-polishing surface humidity fluctuations on sterilization effectiveness. This solution establishes a dynamic correlation between polishing parameters and ultraviolet parameters, forming an adaptive protection mechanism during the polishing stage. This ensures both the appearance quality of the rice grains and achieves synergistic optimization of nutrient retention and sterilization effect.

[0045] Through the above technical solution, this application effectively solves the contradiction between surface treatment of rice grains and internal nutrient protection during the polishing process. While improving the appearance quality of commercial rice, it significantly reduces the broken rice rate caused by mechanical impact, ensures the consistency of sterilization treatment effect, and provides a reliable technical guarantee for the processing of high-quality rice.

[0046] In this embodiment, step S3, the rice milling control stage specifically includes: S3a, the second detection device monitors the particle size, moisture content and bran outlet pressure parameters in real time during the rice milling process; S3b predicts blockages and performs graded cleaning based on the pressure change trend of the bran outlet channel, and adjusts the bran retention rate in conjunction with the multi-stage rice milling process. Among these, particle size monitoring refers to the real-time measurement of rice grain size distribution, which can be achieved using a laser particle size sensor. The degree of grain breakage is detected to determine whether the milling intensity exceeds a safe threshold. Moisture monitoring refers to the dynamic detection of rice grain moisture content during milling, which can be achieved using a near-infrared moisture meter. Changes in rice grain surface humidity are analyzed to adjust milling resistance parameters. Bran discharge channel pressure parameters refer to the fluid resistance data of the bran discharge channel inside the rice milling machine, which can be achieved using a pressure sensor. Pressure fluctuation trends are used to determine the bran deposition state. Blockage prediction refers to establishing a mathematical model based on the rate of change of pressure parameters to predict the level of blockage risk. This can be achieved using time series analysis, triggering an early warning signal by identifying the pressure rise slope. Graded cleaning refers to using differentiated removal methods for different degrees of blockage. This can be achieved using a combination of high-frequency vibration cleaning and airflow cleaning. Mechanical vibration removes the attached bran, which is then discharged using negative pressure airflow. Multi-stage rice milling process refers to dividing the milling process into multiple processing stages, which can be achieved using a layered rice milling machine. The amount of surface layer removed is controlled by adjusting the roller gap and speed at each stage. Specifically, during the rice milling process, a laser particle size sensor continuously collects data on the size distribution of rice grains. When the proportion of broken rice exceeds a preset threshold, the system automatically reduces the pressure of the milling rollers. A near-infrared moisture meter provides real-time feedback on the moisture content of the rice grains, dynamically adjusting the milling intensity based on changes in the load current of the rice milling machine. A pressure sensor monitors the fluid resistance of the bran channel, triggering a grading and cleaning program when the pressure rise rate reaches a critical value. A high-frequency vibration device first periodically taps the inner wall of the channel to remove the attached bran powder, then a centrifugal fan is activated to generate negative pressure airflow to extract the loose bran powder. The multi-stage rice milling machine automatically switches processing stages based on the current bran retention rate. In the coarse milling stage, a larger roller spacing is used to quickly remove the surface layer, while in the fine milling stage, the roller spacing is reduced and the rotation speed is lowered to achieve precise control. Compared to existing technologies, traditional rice milling processes rely solely on periodic shutdowns to clean the bran channels, failing to detect blockage risks in real time and exhibiting low efficiency due to the limited cleaning methods. This solution uses pressure parameter trend analysis to predict blockages, initiating the cleaning process at the initial stage of blockage to avoid sudden shutdowns. It employs a combined vibration and airflow cleaning method to effectively handle bran powder in different adhesion states. Furthermore, by leveraging the layered processing characteristics of a multi-stage rice milling process, it dynamically adjusts the milling parameters of each stage, ensuring milling precision while reducing broken rice caused by mechanical impact. Through the above technical solution, this application solves the problem of increased broken rice rate caused by brisket channel blockage during rice milling, and achieves precise control over brisket retention rate. Real-time monitoring and a graded cleaning mechanism reduce the risk of abnormal equipment vibration and secondary rice grain breakage caused by sudden blockages; the multi-stage milling process with its layered processing method makes the removal of the rice grain surface more uniform and controllable, retaining more nutrients while achieving the target whiteness.

[0047] In this embodiment, in steps S3a and S3b, the second detection device includes a laser particle size sensor, a near-infrared moisture meter, and a pressure sensor; the graded cleaning includes at least two combinations of high-frequency vibration cleaning, airflow cleaning, speed regulation cleaning, and ultrasonic cleaning; and the multi-stage rice milling process involves 2-4 layers of rice milling.

[0048] The second detection device refers to equipment used to collect key parameters of the rice milling process in real time. Specifically, it can be implemented using a laser particle size sensor, a near-infrared moisture meter, and a pressure sensor. The laser particle size sensor measures the size distribution of rice grains using the principle of laser diffraction to identify changes in the proportion of broken rice. The near-infrared moisture meter analyzes the moisture content of rice grains through spectral absorption characteristics to determine changes in milling resistance. The pressure sensor detects the flow resistance of materials within the bran channel using strain gauges or piezoelectric elements to capture blockage signals. Graded cleaning refers to differentiated treatment methods for different degrees of blockage. Specifically, it can be implemented using at least two combinations of high-frequency vibration cleaning, airflow cleaning, speed-adjusting cleaning, and ultrasonic cleaning. High-frequency vibration cleaning loosens accumulated materials through mechanical vibration; airflow cleaning removes bran powder using negative pressure adsorption; speed-adjusting cleaning adjusts material flow by changing the speed of the milling rollers; and ultrasonic cleaning decomposes adhering substances through cavitation. Multi-stage rice milling technology refers to a processing method that controls the milling intensity in stages, specifically using a 2-4 layer milling structure. Each milling unit independently adjusts the milling pressure and gap, gradually removing the surface layer of rice grains based on real-time detection data.

[0049] Specifically, during the rice milling process, a laser particle size sensor continuously monitors the rice grain size distribution, triggering an early warning when the proportion of broken rice increases abnormally. A near-infrared moisture meter provides real-time feedback on changes in rice grain moisture content, providing a basis for adjusting the milling intensity. A pressure sensor captures pressure fluctuations in the bran channel, determining the blockage risk level based on the pressure rise rate. When the pressure change trend exceeds a threshold, the system automatically initiates tiered cleaning: initial blockages are cleared using a combination of high-frequency vibration and airflow, where vibration loosens the accumulated material, which is then removed by airflow suction; severe blockages are cleared by speed adjustment, reducing the material flow resistance by decreasing the milling roller speed. The multi-stage rice milling process employs a layered processing method. The first-stage milling unit uses higher pressure to remove the outer bran, while the subsequent stages gradually reduce the milling intensity based on real-time particle size data, controlling the bran retention rate while ensuring whiteness and avoiding excessive milling that could lead to rice grain breakage.

[0050] Compared to existing technologies, current rice milling equipment typically employs a single cleaning method and lacks a blockage prediction mechanism. When the pressure in the bran outlet channel becomes abnormal, manual cleaning is the only option, leading to decreased processing efficiency. Existing single-layer rice milling processes use fixed milling parameters, which cannot be dynamically adjusted based on the rice grain condition, making them prone to producing broken rice due to excessive milling intensity. This solution utilizes multi-sensor fusion detection to achieve early warning of blockages, combined with a graded cleaning mechanism to maintain continuous production. Through a multi-stage rice milling process, it dynamically matches milling intensity with the physical state of the rice grains, reducing the impact of mechanical impact on rice grain integrity during continuous processing.

[0051] Through the above technical solution, this application can detect the risk of bran channel blockage in real time during the rice milling process and trigger targeted cleaning operations to avoid mechanical stress concentration caused by increased blockage. At the same time, the layered progressive milling process reduces the damage to the rice grain structure caused by the intensity of a single milling, effectively reducing the problem of increased broken rice rate caused by process parameter mismatch or mechanical blockage.

[0052] In this embodiment, step S4, the vacuum packaging step, includes: S4a uses high-barrier composite packaging material, which has both oxygen and moisture barrier properties. S4b is packaged using vacuum packaging technology. High-barrier composite packaging materials refer to packaging materials made by combining at least two layers of films with different functions through co-extrusion or coating processes. Specifically, they can be achieved using a composite structure of polyethylene and ethylene-vinyl alcohol copolymer. The polyethylene layer provides moisture barrier properties, while the ethylene-vinyl alcohol copolymer layer provides oxygen barrier properties. This material blocks the penetration of external oxygen and moisture through physical barriers, inhibiting microbial activity and oxidation reactions. Vacuum packaging refers to the process of sealing a packaging bag after the air inside is drawn to a preset pressure threshold by a vacuum pump. Specifically, it can be achieved by using a double-chamber vacuum packaging machine in conjunction with a heat sealing device. By actively removing the air inside the packaging, the amount of residual oxygen is reduced, forming a double protection mechanism with high-barrier materials. Specifically, in the selection of packaging materials, a polyethylene layer is used to prevent external moisture from penetrating into the packaging, thus avoiding mold growth in the rice due to moisture absorption; an ethylene-vinyl alcohol copolymer layer is used to block oxygen penetration, inhibiting rancidity caused by lipid oxidation. During the process, a vacuum pump removes air from the packaging bag to a preset vacuum level, reducing residual oxygen content, while a heat-sealing device completes the seal, creating a low-oxygen, low-humidity environment inside the packaging. The synergistic effect of the materials and processes isolates the rice from external environmental factors during storage, delaying quality deterioration. Compared to existing technologies, traditional vacuum packaging often uses single-material bags, such as polyethylene bags that only provide moisture barrier properties or polyester bags that only provide oxygen barrier properties, failing to simultaneously prevent the penetration of both moisture and oxygen. Furthermore, some vacuum packaging processes suffer from insufficient vacuum levels, resulting in a significant amount of residual air inside the bag and a risk of oxidation. This solution achieves dual-barrier protection through a layered structure design of composite materials, combined with vacuum technology to further reduce oxygen content, forming multiple layers of protection. Through the above technical solutions, this application effectively inhibits the mold problem caused by moisture absorption in rice during storage, delays the rancidity caused by lipid oxidation, reduces the loss of trace elements such as zinc and selenium, maintains the freshness and nutritional components of rice grains, and thus improves the quality stability of the product during its shelf life.

[0053] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A processing method for reducing the broken rice rate of commercial rice, characterized in that, Includes the following steps: S1. Rice pretreatment stage: S1a. A multi-stage linkage impurity removal process is adopted, which removes large impurities, light impurities, metallic impurities and stones from rice through a combination of graded screening, airflow separation, magnetic separation and gravity destoning, so that the impurity removal rate is ≥99%; S1b. Based on the dynamic adaptation model of rice physical properties and hulling parameters, the first detection device collects rice moisture and hardness data in real time, and the control unit calculates and adjusts the hulling flow rate and roller pressure to achieve closed-loop control. S2. Perform the color sorting and polishing stage; S3. Rice milling control stage; S4. Enter the vacuum packaging stage.

2. The processing method for reducing the broken rice rate of commercial rice according to claim 1, characterized in that, In step S1a, the screening stage uses a three-layer grading screen with screen apertures of 4.0-5.0mm, 2.5-3.0mm, and 1.2-1.8mm, a screen tilt angle of 12°-20°, and a vibration frequency of 45-55Hz; the air separation stage uses a counter-current air separator with an air velocity of 3.0-3.8m / s; the magnetic separation stage is equipped with at least one strong magnetic separator with a magnetic field strength of 7000-12000Gs; and the destoning stage uses a gravity destoner with an air volume of 1500-2200m³ / h and an amplitude of 2-6mm.

3. The processing method for reducing the broken rice rate of commercial rice according to claim 1, characterized in that, In step S1b, the first detection device is a near-infrared spectrometer or a microwave moisture hardness meter.

4. The processing method for reducing the broken rice rate of commercial rice according to claim 1, characterized in that, The control unit incorporates the dynamic adaptation model: The rice hulling flow rate Q = 16 - 0.5 × M, where M is the moisture content of the rice, 12% ≤ M ≤ 16%; The pressure between the rollers is P = 0.06 - 0.1 × H, where H is the hardness of the rice, and 6 kgf ≤ H ≤ 9 kgf; The actuator adjusts the feeding speed via hydraulic cylinders and the pressure between rollers via hydraulic system.

5. The processing method for reducing the broken rice rate of commercial rice according to claim 1, characterized in that, In step S2, the color sorting and polishing stage includes: S2a. A screening structure adapted to rice grain shape is used in conjunction with an optical recognition device to remove discolored and defective grains, with a discolored grain removal rate of ≥98%; S2b. Polishing is performed using a water atomization polishing process combined with ultraviolet sterilization.

6. The processing method for reducing the broken rice rate of commercial rice according to claim 5, characterized in that, The screening structure described in step S2a is a customized mesh screen with a screen aperture size adapted to the target rice grain shape. The optical recognition device is a CCD camera with a resolution of ≥1920×1080 and a recognition wavelength range of 380-720nm. It focuses on identifying mold spots with a gray value ≤55 and discolored grains with RGB values ​​that meet R≥190, ​​G≥170, and B≤160.

7. The processing method for reducing the broken rice rate of commercial rice according to claim 5, characterized in that, In step S2b, the whiteness of the rice grains and the retention rate of trace elements are balanced by adjusting the atomized water volume, polishing speed, and ultraviolet irradiation parameters. The atomized water synergistic polishing process uses an ultrasonic atomizer with atomized particle diameter of 3-12μm, a water temperature of 22-28℃, and a water volume of 0.4-0.6% of the rice weight. The polishing wheel adopts a 2-4 segment speed control with a speed range of 700-1100r / min. The ultraviolet irradiation wavelength is 240-260nm, the irradiation intensity is 250-350μW / cm², and the time is 4-10s. The irradiation parameters are dynamically adjusted according to the surface humidity of the rice grains.

8. The processing method for reducing the broken rice rate of commercial rice according to claim 1, characterized in that, In step S3, the steps for the rice milling control stage include: S3a. The particle size, moisture content, and bran outlet pressure parameters during the rice milling process are monitored in real time using a second detection device; S3b. Based on the pressure change trend of the bran outlet channel, blockage is predicted and graded for cleaning, and the bran retention rate is adjusted in conjunction with the multi-stage rice milling process.

9. The processing method for reducing the broken rice rate of commercial rice according to claim 8, characterized in that, In step S3a, the second detection device includes a laser particle size sensor, a near-infrared moisture meter, and a pressure sensor; in step S3b, the graded cleaning includes at least two combinations of high-frequency vibration cleaning, airflow cleaning, speed adjustment cleaning, and ultrasonic cleaning, and the multi-stage rice milling process involves 2-4 layers of rice milling.

10. The processing method for reducing the broken rice rate of commercial rice according to claim 1, characterized in that, In step S4, the vacuum packaging step includes: S4a. High-barrier composite packaging material is used, wherein the material has oxygen barrier and moisture barrier properties; S4b. Vacuum packaging is used for packaging.

Images