A method for directional dehulling of tartary buckwheat kernels

Abstract

The present application relates to the technical field of agricultural product processing, and particularly relates to a method for directional dehulling of tartary buckwheat kernels. The method comprises the following steps: particle size grading and moisture content detection; warm pressure pretreatment; edge grinding and shell layer detection; flexible rubbing; multi-stage separation and visual detection; classification determination; and low-temperature drying and packaging. The present application actively widens the gap between the shell and kernel by heating and pressurizing pretreatment, thereby avoiding kernel breakage caused by simply increasing mechanical force. The present application combines tartary buckwheat shell powder particle size detection and visual detection to classify the un-dehulled kernels into un-cracked type, cracked but not dehulled type and broken shell sticking type, and returns them to the corresponding process for reprocessing. Meanwhile, the process parameters are adjusted according to the proportion of each type, so as to realize closed-loop adaptive control. Furthermore, the present application avoids thermal degradation of flavonoid active ingredients caused by high temperature through whole-process low-temperature drying control, thereby ensuring the dehulling effect while taking into account kernel integrity and flavonoid retention rate.

Description

Technical Field

[0001] This invention relates to the field of agricultural product processing technology, and in particular to a method for directional dehulling of buckwheat seeds. Background Technology

[0002] Because of its hard outer shell and tight adhesion to the kernel, the dehulling process of buckwheat has long been a challenge for the industry. Traditional mechanical dehulling methods easily result in high kernel breakage and incomplete dehulling, while heat treatments such as steaming and boiling can cause varying degrees of degradation of flavonoid active ingredients, affecting nutritional quality. Especially for high-flavonoid buckwheat varieties with higher flavonoid content, how to achieve efficient and gentle hull-kernel separation while preserving its core nutrients and active ingredients is a key technical bottleneck restricting the deep processing and high-value development of the buckwheat industry.

[0003] Chinese Patent Publication No. CN103920555A discloses a non-thermal dehulling method for tartary buckwheat. The method includes: removing impurities from the raw material; grinding the tartary buckwheat raw material with a small contact force to grind away the more prominent angular parts on its outer shell, so that the angular parts of the tartary buckwheat outer shell are fully ground while the endosperm and the conical ventral groove are not ground; causing the outer shell to undergo small deformation by rubbing, rolling or slight impact, further causing the outer shell to crack and finally separate from the kernel; and separating the shell and kernel by airflow cleaning.

[0004] Therefore, the existing technology has the following technical problems: it is a general dehulling solution for common buckwheat varieties, and it has not been adapted to the shell characteristics of high-flavonoid buckwheat varieties, nor has it been optimized for parameters or processes. When directly applied to high-flavonoid buckwheat, the dehulling effect is poor; it adopts a purely physical dehulling path of grinding and then rubbing, relying on mechanical force to forcibly break the shell-kernel bond, and lacks an active pretreatment step to weaken the shell-kernel bond. For high-flavonoid buckwheat with a tight shell-kernel bond, the mechanical force needs to be increased to achieve the dehulling effect, which exacerbates the risk of kernel breakage; it is an open-loop control, lacking online detection methods for the shell breakage state during the dehulling process and a closed-loop feedback adjustment mechanism based on the detection results. It cannot adaptively adjust process parameters according to fluctuations in raw material quality, resulting in insufficient stability of the dehulling effect. Summary of the Invention

[0005] To address this, the present invention provides a method for directional dehulling of buckwheat seeds, which overcomes the problems in the prior art where the lack of a suitable solution for the characteristics of high-flavonoid buckwheat varieties leads to the failure to actively weaken the binding force between the husk and kernel, resulting in the need to increase the force to separate the husk and kernel during dehulling, leading to a high kernel breakage rate, severe loss of flavonoid active ingredients, and unstable dehulling effect.

[0006] To achieve the above objectives, the present invention provides a method for directional dehulling of buckwheat seeds, comprising: High-flavonoid buckwheat seeds were selected for particle size classification, and the moisture content of each particle size fraction was detected. Based on the moisture content of each particle size, the temperature and pressure pretreatment parameters for expanding the gap between the kernel and husk of the graded grains placed in a sealed container are determined, so as to carry out temperature and pressure pretreatment and obtain pretreated samples. Based on the particle size classification results, grinding parameters are determined to perform grinding and edge removal on the pretreated sample to obtain a ground sample. Buckwheat hull powder generated during the grinding and edge removal process is collected, and the particle size distribution characteristics of the buckwheat hull powder are detected to obtain the shell breakage state detection results. Based on the particle size classification results, the rolling parameters are determined to perform flexible rolling on the grinding sample to obtain the rolled mixture. Multi-stage separation is performed based on the particle size differences between buckwheat kernels, buckwheat hulls, and unthreshed grains in the mixture. Visual inspection is then performed on the separated unthreshed grains in conjunction with the results of the hull breakage detection to obtain visual inspection results. Based on the visual inspection results and the shell breakage state inspection results, the corresponding processes for various types of unremoved kernels are determined for reprocessing. At the same time, the temperature and pressure pretreatment parameters, grinding parameters, and rolling parameters are adjusted according to the proportion of unremoved kernels and the shell breakage state. Based on the moisture content of the buckwheat kernels obtained after multi-stage separation and the preset thermal degradation temperature, the drying temperature limit and target moisture content are determined, and the separated buckwheat kernels are dried to the target moisture content before packaging.

[0007] Furthermore, the process of determining the temperature and pressure pretreatment parameters includes: Based on the heat softening characteristics of high-flavonoid buckwheat hulls and the thermal degradation temperature of flavonoids, the heating temperature for pretreatment was determined. Based on the moisture content of each particle size, the pressurization pressure and holding time are determined; Based on the particle size classification results, the number of cycles is determined; The heating temperature, pressurization pressure, holding time, and number of cycles are used as temperature and pressure pretreatment parameters.

[0008] Furthermore, the process of determining grinding parameters includes: Based on the particle size classification results, the average particle size of each particle size class is obtained; Based on the average particle size of each particle size, determine the grinding clearance corresponding to each particle size; The grinding depth corresponding to each particle size was determined based on the thickness of the high-flavonoid buckwheat hull. The grinding clearance and grinding depth corresponding to each grain size are used as grinding parameters.

[0009] Furthermore, the process of detecting the shell fragmentation state includes: Buckwheat hull powder generated during the grinding and de-edge-removing process was collected as a test sample. The test sample was sieved to obtain the mass percentage of buckwheat hull powder with different particle size ranges, and the particle size distribution test results were obtained. When the mass percentage of fine powder exceeds the fine powder threshold, the shell fragmentation state is determined to be excessively fragmented. In response to the fact that the mass percentage of coarse powder exceeds the coarse powder threshold, the shell fragmentation state is determined to be insufficient.

[0010] Furthermore, the process of determining the kneading parameters includes: Based on the particle size classification results, the average particle size of each particle size class is obtained; The rubbing gap for each particle size is determined based on the average particle size of the material in each particle size; The rolling speed ratio corresponding to each particle size was determined based on the binding force of high-flavonoid tartary buckwheat hull kernels. The rubbing gap and rubbing speed ratio corresponding to each particle size are used as rubbing parameters.

[0011] Furthermore, the process of performing multi-stage separation on the mixture includes: Based on the specific gravity difference between buckwheat hulls, buckwheat kernels, and unthreshed grains, the mixture after hulling and crushing was separated by air separation to separate the buckwheat hulls and obtain the remaining material after air separation. Based on the particle size difference among the remaining materials after air separation, they are screened and separated to separate buckwheat kernels, resulting in unthreshed grains. The unthreshed grains are sent to the visual inspection process as the objects of visual inspection.

[0012] Furthermore, the process of visually inspecting unthreshed kernels includes: Images of unthreshed grains were collected. Based on the image, characteristic parameters were extracted from the shell integrity, kernel-shell bonding state, and residual amount of unequal-threshed kernels. The visual detection result is determined based on the aforementioned feature parameters.

[0013] Furthermore, the process for determining the corresponding steps for each type of unthreshed grain includes: Based on the visual inspection results and the shell breakage state inspection results, the unthreshed kernels are divided into three types: uncracked, cracked but not threshed, and broken shells stuck together. Uncracked types are returned to the pretreatment process, cracked but not detached types are returned to the flexible rolling process, and types with broken shells adhering to the shell are returned to the grinding and de-edge removal process.

[0014] Furthermore, the process of adjusting the temperature and pressure pretreatment parameters, grinding parameters, and rolling parameters includes: The percentage of each type of unthreshed grain was statistically analyzed. If the proportion of uncracked cells exceeds the first preset threshold, the holding time is extended or the number of cycles is increased. In response to a higher-than-preset threshold for the proportion of cracked but undeformed parts, adjust the rubbing gap or rubbing speed ratio. In response to the proportion of shell fragments adhering to the surface exceeding the third preset threshold, the grinding depth is increased.

[0015] Furthermore, the process of determining the drying temperature limits and target moisture content includes: The moisture content of the buckwheat kernels obtained after multi-stage separation was measured. The thermal degradation temperature of flavonoids in high-flavonoid buckwheat was obtained, and the drying temperature limit was determined based on the thermal degradation temperature. The target moisture content is determined based on the moisture content and the preset safe storage moisture content threshold. The drying temperature limit and the target moisture content are used as drying parameters. The buckwheat kernels are dried according to the drying parameters, and the drying temperature is controlled not to exceed the drying temperature limit during the drying process. Drying is terminated when the moisture content of the buckwheat kernels reaches the target moisture content.

[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: Firstly, this invention grades the high-flavonoid buckwheat kernels by particle size and determines the corresponding temperature and pressure pretreatment parameters based on the moisture content of each particle size. This ensures that kernels of different sizes can form suitable husk-kernel gaps, improving the adaptability of subsequent dehulling processes. Furthermore, based on the particle size grading results, grinding and rubbing parameters are determined separately, matching the grinding and rubbing actions to different kernel sizes. This reduces buckwheat kernel breakage while increasing dehulling efficiency. Simultaneously, this invention collects the buckwheat husk powder generated during the grinding process and utilizes the particle size distribution characteristics of the husk powder to determine the husk breakage state. This transforms the buckwheat husk powder from a byproduct of traditional dehulling into process feedback information reflecting the grinding state, enabling timely identification of insufficient or excessive grinding and improving the precision of grinding process control. Further combining the visual inspection results after multi-stage separation, different types of unthreshed grains are classified and recirculated. Based on the proportion of unthreshed grains and the state of hull breakage, the temperature and pressure pretreatment parameters, grinding parameters, and rubbing parameters are simultaneously adjusted, forming a dual feedback closed-loop control covering the entire pretreatment, grinding, and dehulling process. This reduces the rate of repeated processing and improves the overall threshing rate and product consistency of buckwheat grains. Finally, based on the moisture content of buckwheat kernels and the thermal degradation temperature of flavonoids, drying temperature limits and target moisture content are determined. This ensures the storage stability of buckwheat kernels while reducing the thermal degradation of high-flavonoid active ingredients due to excessively high drying temperatures, thus balancing dehulling efficiency, product quality, and the retention of high-flavonoid active ingredients. Attached Figure Description

[0017] Figure 1 This is a flowchart of the buckwheat seed-directed dehulling method in this embodiment; Figure 2 This is a flowchart illustrating the determination of temperature and pressure pretreatment parameters in this embodiment; Figure 3 This is a logic diagram of grinding and shell detection in this embodiment; Figure 4 This is a logic diagram of the separation detection and closed-loop parameter tuning in this embodiment. Detailed Implementation

[0018] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0019] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0020] Please see Figure 1 The diagram shown is a flowchart of the buckwheat grain-directed dehulling method in this embodiment. This embodiment provides a buckwheat grain-directed dehulling method, including: Step S1: Select high-flavonoid buckwheat seeds for particle size classification, and use a moisture analyzer to detect the moisture content of each particle size classification result. The particle size is divided into three grades: large, medium and small. Step S2: Determine the temperature and pressure pretreatment parameters for expanding the gap between the kernel and husk of the graded grains in a sealed container based on the moisture content of each grain size, so as to carry out temperature and pressure pretreatment and obtain pretreated samples. Step S3: Determine grinding parameters based on the particle size classification results, and perform grinding and edge removal on the pretreated sample to obtain a ground sample. Collect the buckwheat hull powder generated during the grinding and edge removal process, detect the particle size distribution characteristics of the buckwheat hull powder, and obtain the shell breakage state detection results. Step S4: Determine the rolling parameters based on the particle size classification results, and perform flexible rolling on the grinding sample to obtain the rolled mixture. Step S5: Based on the particle size difference between buckwheat kernels, buckwheat hulls and unthreshed grains in the mixture, perform multi-stage separation, and combine the hull breakage state detection results to perform visual inspection on the separated unthreshed grains to obtain visual inspection results. Step S6: Based on the visual inspection results and the shell breakage state inspection results, determine the corresponding process for each type of unthreshed kernels to be returned for reprocessing. At the same time, adjust the temperature and pressure pretreatment parameters, grinding parameters, and rolling parameters according to the proportion of unthreshed kernels and the shell breakage state. Step S7: Based on the moisture content of the buckwheat kernels obtained after multi-stage separation and the preset thermal degradation temperature, determine the drying temperature limit and target moisture content, and then package the separated buckwheat kernels after drying them to the target moisture content.

[0021] Specifically, this invention first classifies high-flavonoid buckwheat kernels by particle size and determines corresponding temperature and pressure pretreatment parameters based on the moisture content of each particle size. This ensures that kernels of different sizes can form suitable husk-kernel gaps, improving the adaptability of subsequent dehulling processes. Furthermore, based on the particle size classification results, grinding and rubbing parameters are determined to match the grinding and rubbing actions with different kernel sizes, reducing buckwheat kernel breakage while increasing dehulling efficiency. Simultaneously, this invention collects buckwheat husk powder generated during the grinding process and utilizes the particle size distribution characteristics of the husk powder to determine the husk breakage state. This transforms the buckwheat husk powder from a byproduct of traditional dehulling into process feedback information reflecting the grinding state, enabling timely identification of insufficient or excessive grinding and improving the precision of grinding process control. Further combining the visual inspection results after multi-stage separation, different types of unthreshed grains are classified and recirculated. Based on the proportion of unthreshed grains and the state of hull breakage, the temperature and pressure pretreatment parameters, grinding parameters, and rubbing parameters are simultaneously adjusted, forming a dual feedback closed-loop control covering the entire pretreatment, grinding, and dehulling process. This reduces the rate of repeated processing and improves the overall threshing rate and product consistency of buckwheat grains. Finally, based on the moisture content of buckwheat kernels and the thermal degradation temperature of flavonoids, drying temperature limits and target moisture content are determined. This ensures the storage stability of buckwheat kernels while reducing the thermal degradation of high-flavonoid active ingredients due to excessively high drying temperatures, thus balancing dehulling efficiency, product quality, and the retention of high-flavonoid active ingredients.

[0022] Please see Figure 2 As shown, this is a flowchart illustrating the determination of temperature and pressure pretreatment parameters in this embodiment. The process for determining these parameters includes: The thermal degradation temperature of flavonoids in high-flavonoid buckwheat was obtained, and a safe heating range below the thermal degradation temperature was determined based on the softening characteristics of the buckwheat hull. A pretreatment heating temperature was selected from the safe heating range to achieve sufficient weakening of the buckwheat hull while avoiding degradation of flavonoids due to overheating. The softening characteristics of the buckwheat hull were obtained by subjecting the sample to gradient heating treatment and detecting the change in hardness or compressive strength of the buckwheat hull with temperature. The temperature range corresponding to when the hardness of the buckwheat hull begins to decrease significantly was taken as the softening range of the buckwheat hull.

[0023] The moisture content of each grain size of buckwheat kernels was obtained, and the moisture regulation intensity was determined based on the difference between the moisture content of each grain size and the target moisture content. When the moisture content was higher than the target moisture content, the pressurization pressure was increased or the holding time was extended. When the moisture content was close to the target moisture content, the pressurization pressure was reduced or the holding time was shortened, so that the pressure could be transmitted to the kernel-husk interface.

[0024] The average particle size of each size of buckwheat grain is obtained, and the number of pretreatment cycles is determined based on the average particle size. The size of the grain with a larger average particle size corresponds to more cycles, and the size of the grain with a smaller average particle size corresponds to fewer cycles, so that the shell-kernel bonding force of materials with different particle sizes can be weakened to the same degree.

[0025] The determined heating temperature, pressurization pressure, holding time, and number of cycles are combined, and the correlation between each particle size and the corresponding temperature and pressure pretreatment parameters is established, so that the heating temperature, pressurization pressure, holding time, and number of cycles can be used as temperature and pressure pretreatment parameters.

[0026] In this embodiment, the temperature and pressure pretreatment is carried out using a closed pretreatment device. This closed pretreatment device is a conventional piece of equipment used in agricultural product processing for grain temperature and pressure regulation. It typically includes a heating control unit, a pressure regulating unit, a pressure relief unit, and control units, among other actuators, to control the temperature, pressure, and pressure holding process of the material placed within the closed cavity. This embodiment does not limit the specific structure of the closed pretreatment device; instead, it inputs predetermined temperature and pressure pretreatment parameters into an existing closed pretreatment device, causing it to operate according to these parameters.

[0027] In this embodiment, the temperature and pressure pretreatment process includes: inputting the heating temperature to the control unit of the sealed pretreatment device, which calls the heating control unit to adjust the output power of the heating element according to the target heating temperature so that the kernel temperature reaches the heating temperature; inputting the pressurization pressure to the pressure regulating unit, which adjusts the internal pressure of the sealed container to the target pressure by controlling the working status of the booster pump, air inlet valve and pressure relief valve, and maintains the pressure holding time; after the pressure holding is completed, the heating, pressurization and pressure relief processes are repeated according to the number of cycles, so that the sealed pretreatment device operates according to the determined temperature and pressure pretreatment parameters to promote the migration of moisture to the kernel interface and expand the kernel gap.

[0028] Specifically, this invention first combines heating temperature, pressurization pressure, holding time, and number of cycles into a unified temperature-pressure pretreatment parameter system. This allows the control parameters in the pretreatment stage to be synergistically matched according to the characteristics of the raw material, its moisture content, and particle size distribution. Specifically, the heating temperature is constrained by the softening characteristics and thermal degradation temperature of buckwheat hulls, ensuring that the buckwheat hulls are sufficiently weakened at a temperature below the flavonoid degradation temperature. The pressurization pressure and holding time are adaptively adjusted according to changes in moisture content, ensuring that materials with different moisture contents can achieve sufficient gas permeation. The number of cycles is set differently according to particle size, ensuring that the shell-kernel bonding force of materials with different particle sizes reaches the same degree of weakening. Thus, the pretreatment stage actively creates conditions for shell-kernel separation before the material enters the subsequent dehulling process, allowing subsequent mechanical dehulling to be carried out on a material with sufficiently weakened shell-kernel bonding force. This ensures the dehulling effect while reducing kernel breakage caused by forced separation.

[0029] Please see Figure 3 As shown, this is a logic diagram of grinding and shell detection in this embodiment. In this embodiment, the process of determining grinding parameters includes: Obtain the particle size data of buckwheat seeds in each particle size class, and calculate the average particle size of the corresponding particle size class based on the particle size data of all buckwheat seeds in each particle size class, so as to obtain the average particle size of the material in each particle size class based on the particle size classification results.

[0030] The average particle size of each particle size is obtained, and the grinding gap is determined based on the average particle size. The particle size with a larger average particle size corresponds to a larger grinding gap, and the particle size with a smaller average particle size corresponds to a smaller grinding gap, so that the grinding action is on the outer surface of the buckwheat hull and avoids grinding to the buckwheat kernel. The grinding gap corresponding to each particle size is determined based on the average particle size of each particle size material.

[0031] The thickness of high-flavonoid buckwheat hulls is obtained, and the grinding depth is determined based on the thickness of the buckwheat hulls. The grinding depth is less than the thickness of the buckwheat hulls of the corresponding grain size, so as to weaken the continuous structure of the buckwheat hulls without abrading the buckwheat kernels during the grinding and de-edge removal process. The grinding depth corresponding to each grain size is determined based on the thickness of the high-flavonoid buckwheat hulls.

[0032] The grinding clearance and grinding depth corresponding to each grit size are combined accordingly, and the correlation between each grit size and the corresponding grinding parameters is established, so that the grinding clearance and grinding depth corresponding to each grit size can be used as grinding parameters.

[0033] In this embodiment, the grinding depth is determined based on the principle of not penetrating the buckwheat hull, so that the grinding action is mainly concentrated on the edges and outer tissue of the buckwheat hull, thereby weakening the overall strength of the buckwheat hull and creating conditions for easy cracking of the hull layer in subsequent flexible rolling, while avoiding exposure or damage to the buckwheat kernel.

[0034] In this embodiment, the grinding and de-edge removal process is performed using a grain grinding device from the existing agricultural product processing field. This grinding device is a conventional piece of equipment used for removing the surface layer of grains or seeds. It typically includes feeding components, grinding components, gap adjustment components, power drive components, and control components, etc., used to remove the outer layer of the grain by adjusting the grinding gap, grinding intensity, and grinding time. This embodiment does not limit the specific structure of the grinding device, but rather inputs predetermined grinding parameters into an existing grinding device, causing it to complete the grinding and de-edge removal process according to the corresponding parameters.

[0035] In this embodiment, the grinding and de-edge removal process includes: inputting the grinding gap corresponding to each particle size to the control component of the grinding device; the control component controls the gap adjustment component to adjust the distance between the grinding roller and the contact surface of the grain, so that the grinding gap matches the average particle size of the material of the corresponding particle size; converting the grinding depth into the feed amount or grinding pressure control parameter of the grinding component, and inputting it to the drive control component of the grinding device; controlling the amount of material removed by adjusting the moving distance, extrusion pressure or action time of the grinding component, so that the grinding depth is less than the thickness of the buckwheat hull of the corresponding particle size; controlling the operation of the grinding device according to the grinding parameters corresponding to different particle sizes, so that the grinding action is concentrated on the edges and outer tissue of the buckwheat hull, so as to weaken the continuous structure of the hull and avoid grinding penetrating to the kernel.

[0036] Specifically, this invention determines the grinding gap and grinding depth independently, allowing each parameter to serve different control objectives. The grinding gap varies with particle size to accommodate the size differences of materials with different particle sizes, ensuring that large particles have sufficient space to move within the grinding chamber without being over-clamped, and that small particles are adequately constrained within the grinding chamber without shaking. This ensures that materials of different particle sizes are under similar stress during the grinding process. The grinding depth is uniformly set based on the thickness of the buckwheat hull, controlling the amount of material removed based on the principle of not penetrating the buckwheat hull. This concentrates the grinding action on the edges and outer layers of the buckwheat hull, ensuring the integrity of the inner layer of the buckwheat hull while removing the edges, thus avoiding exposure or damage to the endosperm. As a result, the grinding stage achieves the desired effect simultaneously in two dimensions: effective removal of edges and protection of the endosperm.

[0037] In this embodiment, the process of detecting the shell fracture state includes: Buckwheat hull powder generated during the grinding and de-edge removal process was collected as a test sample.

[0038] The collected buckwheat hull powder was sieved using a standard sieve, so that powder of different particle size ranges was trapped on sieves with different aperture sizes. By weighing the powder on each sieve layer, the mass ratio of powder of each particle size range was calculated to obtain the particle size distribution test results. Among them, the mass ratio of fine powder reflects the fineness of the buckwheat hull grinding, and the mass ratio of coarse powder reflects whether the buckwheat hull has been fully crushed.

[0039] When the mass percentage of fine powder exceeds the fine powder threshold, the shell fragmentation state is determined to be excessive, indicating that the current grinding depth is too large or the grinding force is too strong, resulting in the buckwheat hull being excessively crushed.

[0040] When the mass percentage of coarse powder exceeds the coarse powder threshold, the shell fragmentation state is determined to be insufficient, indicating that the current grinding depth is too small or the grinding force is insufficient, resulting in the buckwheat shells not being effectively broken.

[0041] Since the mass percentage of fine powder does not exceed the fine powder threshold and the mass percentage of coarse powder does not exceed the coarse powder threshold, the shell breakage state is determined to be normal, indicating that the current grinding parameters are within the appropriate range.

[0042] In this embodiment, the fine powder threshold and coarse powder threshold are obtained by repeated experiments on the same variety of high-flavonoid buckwheat under normal grinding conditions that meet the preset requirements for dehulling effect and kernel integrity. The upper limits of the fine powder mass ratio and coarse powder mass ratio are determined by statistically analyzing the distribution range of fine powder mass ratio and coarse powder mass ratio in each experiment, and the corresponding upper limits are used as the fine powder threshold and coarse powder threshold.

[0043] In this embodiment, the detection of shell fragmentation status is performed using a powder particle size detection device from the existing agricultural product processing testing field. This device is a conventional instrument for particulate matter particle size analysis, typically including a sieving component, a weighing component, and a data processing component, used to acquire the particle size distribution characteristics of the shell powder generated during the grinding process. This embodiment does not limit the specific structure of the powder particle size detection device, but rather uses the detection results of the shell powder generated during the grinding process to provide feedback and judgment on the operating status of the grinding device.

[0044] In this embodiment, the process of detecting the shell breakage state includes: feeding the collected buckwheat hull powder into a powder particle size detection device; classifying and retaining the hull powder according to a preset particle size range using a sieving component; and obtaining the mass of hull powder within each particle size range using a weighing component; inputting the mass of hull powder within each particle size range into a data processing component; calculating the mass ratio of powder within different particle size ranges; and comparing it with preset fine powder thresholds and coarse powder thresholds to determine the current shell breakage state; and in response to whether the shell breakage state is over-breakage or under-breakage, sending the corresponding detection result to the control component of the grinding device, which adjusts the operating parameters of the grinding component. Specifically, when it is determined to be over-breakage, the grinding depth is reduced or the grinding intensity is decreased; when it is determined to be under-breakage, the grinding depth is increased or the grinding intensity is increased, so that the subsequent grinding process remains within the target breakage state range.

[0045] Specifically, this invention solves the problem of lack of quality feedback in the grinding process by collecting and sieving the buckwheat hull powder generated during the grinding and de-edge removal process. This eliminates the reliance on operator experience to determine the appropriate grinding depth, instead using the powder particle size distribution detection results as the direct indicator. When the proportion of fine or coarse powder exceeds a threshold, it indicates that the current grinding depth has deviated from the optimal range and needs to be adjusted accordingly. This ensures that the direction and magnitude of the grinding depth adjustment are derived from detection data rather than empirical estimation, avoiding adjustment errors caused by experience-based judgments. Furthermore, it establishes a feedback path within the grinding process where the detection results directly determine the adjustment direction.

[0046] In this embodiment, the process of determining the rolling parameters includes: Obtain the particle size data of buckwheat seeds in each particle size class, and calculate the average particle size of the corresponding particle size class based on the particle size data of all buckwheat seeds in each particle size class, so as to obtain the average particle size of the material in each particle size class based on the particle size classification results.

[0047] The average particle size of each particle size is obtained, and the rubbing gap of each particle size is determined according to the average particle size. The particle size with a larger average particle size corresponds to a larger rubbing gap, and the particle size with a smaller average particle size corresponds to a smaller rubbing gap, so that the large particle size material has enough room to move during rubbing without being over-compressed, and the small particle size material is sufficiently constrained during rubbing without shaking. The rubbing gap of each particle size is determined based on the average particle size of each particle size material.

[0048] In this embodiment, to obtain the husk-kernel binding force of high-flavonoid buckwheat kernels, randomly selected high-flavonoid buckwheat kernels from the current batch were used as test samples. The force required to separate the husk from the kernel was measured through a husk-kernel peeling test. The high-flavonoid buckwheat kernels are distinct from ordinary buckwheat kernels; the varieties corresponding to their high-flavonoid characteristics were screened by flavonoid content testing. The husk-kernel binding force was obtained by randomly selecting kernels and conducting a husk-kernel peeling test to determine the tightness of the bond between the husk and kernel of the current batch of high-flavonoid buckwheat kernels.

[0049] A shell-kernel separation test was conducted on the current batch of high-flavonoid buckwheat kernels. The peak force required for the separation of the shell from the kernel was measured as the shell-kernel binding force. The rubbing speed ratio was determined based on the shell-kernel binding force. The rubbing speed ratio is used to characterize the relative rotational speed difference between the two rubbing components. The stronger the shell-kernel binding force, the larger the rubbing speed ratio is set to generate sufficient shell-kernel separation shearing action. The weaker the shell-kernel binding force, the lower the rubbing speed ratio is to reduce the shearing impact on the kernel.

[0050] The corresponding rubbing gap and rubbing speed ratio of each particle size are combined accordingly, and the correlation between each particle size and the corresponding rubbing parameters is established, so that the rubbing gap and rubbing speed ratio of each particle size are used as rubbing parameters.

[0051] In this embodiment, the flexible rubbing and grinding process is carried out using a conventional rubbing and grinding device used in the field of agricultural product processing for grain dehulling. This device typically includes rubbing and grinding roller assemblies, gap adjustment assemblies, power drive assemblies, and control assemblies, etc., to achieve flexible peeling of the grain shell by adjusting the rubbing and grinding gap and speed ratio. This embodiment does not limit the specific structure of the rubbing and grinding device, but rather inputs predetermined rubbing and grinding parameters into an existing rubbing and grinding device, causing it to complete the kernel-shell separation process according to the corresponding parameters.

[0052] In this embodiment, the process of performing flexible rubbing and grinding includes: inputting the rubbing and grinding gap corresponding to each particle size to the control component of the rubbing and grinding device; the control component controls the gap adjustment component to adjust the distance between the two rubbing and grinding components so that the rubbing and grinding gap matches the average particle size of the corresponding particle size; inputting the rubbing and grinding speed ratio to the power drive component; by adjusting the rotation speed of the relatively rotating rubbing and grinding components respectively, a speed difference corresponding to the shell-kernel bonding force is formed between the two rubbing and grinding components to generate a shearing action that meets the shell-kernel separation requirements of the current batch of high-flavonoid buckwheat seeds; controlling the operation of the rubbing and grinding device according to the rubbing and grinding parameters corresponding to different particle sizes, so that the shell is separated from the kernel under flexible extrusion and shearing action, while avoiding kernel breakage due to excessive force.

[0053] Specifically, this invention determines the rubbing gap and rubbing speed ratio based on different factors, allowing each parameter to independently match different material characteristics. The rubbing gap varies with particle size to accommodate the size differences of materials with different particle sizes, ensuring that larger particles have sufficient space to move and smaller particles are adequately constrained, resulting in a more consistent degree of compression and shearing effect for all particle sizes during the rubbing process. The rubbing speed ratio varies with the shell-kernel bonding force to adapt to the actual peeling difficulty of the current batch of material, matching the shearing force provided by rubbing with the force required for shell-kernel separation. A high speed ratio is used to provide sufficient shearing force when the shell-kernel bonding force is strong, while a low speed ratio is used when the shell-kernel bonding force is weak to avoid damaging the kernel. Thus, the two parameters in the rubbing stage are independently adapted for two different dimensions: material size and shell-kernel bonding state. In the same rubbing process, both the uniformity of force on materials of different particle sizes and the differentiated force requirements for materials with different peeling difficulties are simultaneously considered.

[0054] In this embodiment, the multi-stage separation process employs a multi-stage separation device used in agricultural product processing for separating kernels and husks. This multi-stage separation device is a conventional, existing equipment, typically including air separation units, sieving units, conveying units, and control units, used to separate the husks, kernels, and unremoved kernels according to the material characteristics. This embodiment does not limit the specific structure of the multi-stage separation device.

[0055] Please see Figure 4 As shown, this is a logic diagram of the separation detection and closed-loop parameter tuning in this embodiment. In this embodiment, the multi-level separation process includes: Based on the specific gravity difference between buckwheat hulls, buckwheat kernels, and unthreshed grains, air separation parameters are determined, including airflow velocity, air volume, and material conveying speed. These parameters are then sent to the air separation control unit of the multi-stage separation device. The airflow velocity within the separation chamber is controlled by adjusting the fan speed, the airflow carrying capacity is controlled by adjusting the air volume, and the material entry speed is adjusted by the conveying control unit. After the hulled mixture enters the air separation area, the buckwheat hulls are carried away and collected by the airflow, while the buckwheat kernels and unthreshed grains, due to their greater mass, continue to fall, thus separating the buckwheat hulls from the mixture and obtaining the remaining air-separated material containing buckwheat kernels and unthreshed grains.

[0056] Based on the particle size difference between buckwheat kernels and unthreshed grains in the remaining material after air separation, screening and separation parameters are determined, including screen aperture, vibration frequency, and screening time. The determined screening and separation parameters are sent to the screening control unit. By selecting a screen with the corresponding aperture and adjusting the vibration frequency of the vibration drive mechanism, the buckwheat kernels fall through the screen and are collected as buckwheat kernel products during the screening process, while the unthreshed grains, because their particle size is larger than the screen aperture, are trapped above the screen and collected as unthreshed grains, thus separating the buckwheat kernels from the remaining material after air separation.

[0057] The unthreshed grains obtained after screening are sent to the visual inspection process through a conveying unit, so that the unthreshed grains pass through the visual acquisition area in sequence at a preset conveying speed, so that the visual inspection unit can acquire images of the unthreshed grains one by one and classify them.

[0058] Specifically, this invention first separates the mixture after the buckwheat hulls have been crushed by air separation. Utilizing the difference in specific gravity between the buckwheat hulls (lower density) and the buckwheat kernels (higher density) and unthreshed grains, the buckwheat hulls are carried away by the airflow, while the kernels and unthreshed grains fall, thus separating the buckwheat hulls from the mixture and preventing them from clogging the screens in subsequent screening processes. The remaining material after air separation is then screened. Taking advantage of the difference in particle size between the buckwheat kernels (smaller size) and the unthreshed grains (larger size), the buckwheat kernels pass through the screen and are collected, while the unthreshed grains are retained. Above the sieve, the buckwheat kernels are separated from the remaining material. After the above two separation steps, the rubbed mixture is separated into three categories of independently collected materials: buckwheat hulls, buckwheat kernels, and unthreshed grains. The buckwheat hulls can be collected and used directly, the buckwheat kernels are collected as finished products, and the unthreshed grains are sent to the subsequent visual inspection process. This avoids the problem of the three materials being mixed and unable to be classified and processed. At the same time, the subsequent visual inspection only needs to process the single type of material, the unthreshed grains, without having to distinguish between the three different materials in the inspection process.

[0059] In this embodiment, visual inspection of unthreshed grains is performed using a visual inspection device for grain appearance inspection in the agricultural product processing field. This visual inspection device is a conventional, existing equipment, typically including an image acquisition unit, a light source adjustment unit, a conveying and positioning unit, and an image processing unit, used for image acquisition and feature recognition of the grains during the conveying process. This embodiment does not limit the specific structure of the visual inspection device.

[0060] In this embodiment, the process of visually inspecting unthreshed kernels includes: The unthreshed kernels obtained after screening are conveyed to the visual inspection area. Image acquisition parameters are determined based on the size of the unthreshed kernels and the conveying speed. These image acquisition parameters include camera acquisition frequency, exposure time, and light source brightness. The determined image acquisition parameters are sent to the image acquisition control unit of the visual inspection device. By adjusting the matching relationship between the camera acquisition frequency and the conveying speed, at least one complete image is acquired when the unthreshed kernels pass through the inspection area. The contrast between the kernel shell and the background is improved by adjusting the exposure time and light source brightness.

[0061] Image preprocessing is performed on the collected images of unthreshed grains, including image enhancement, background segmentation, and adhesion segmentation. Image enhancement is used to improve image contrast, background segmentation is used to extract grain contours based on the grayscale difference between the grain area and the background area, and adhesion segmentation is used to segment grains that are in contact or overlapping into independent individuals to obtain an independent image corresponding to each unthreshed grain.

[0062] Based on the preprocessed independent images, feature parameters of the shell integrity, shell-kernel bonding state, and edge residue of each unthreshed kernel were extracted using image processing algorithms. The shell integrity was obtained by detecting the ratio between the area of ​​the cracked area on the shell surface and the projected area of ​​the shell. The shell-kernel bonding state was obtained by detecting the width of the visible gap between the edge of the shell and the edge of the kernel. The edge residue was obtained by detecting the residual height of the three edge regions of the kernel. These parameters respectively characterize the degree of shell breakage, the degree of shell-kernel separation, and the edge removal effect of the unthreshed kernel.

[0063] Based on the extracted feature parameters, the visual inspection results of each unthreshed kernel are determined. The visual inspection results are sent to the classification control unit. Based on the combination relationship between shell integrity, shell-kernel bonding state and residual amount of edges, the unthreshed kernels are classified into uncracked type, cracked but not threshed type, and broken shell-adhered type, so that the classification results can be used as the basis for subsequent return path control.

[0064] Specifically, this invention first performs adhesion segmentation processing on the image, separating contacting or stacked grains into individual units before feature extraction. This allows feature parameters such as shell integrity, kernel-shell gap, and residual angularity to be accurately extracted in the independent state of each grain, avoiding interference between feature parameters caused by grain overlap. Based on this, the extracted shell integrity, kernel-shell bond state, and residual angularity are simultaneously used as classification criteria. The final classification result comprehensively reflects the state of incompletely threshed grains in three dimensions: appearance damage, kernel-shell separation, and residual angularity. This allows the recycling process to directly determine the corresponding process based on the classification result upon receiving it, eliminating the need for secondary judgment of the incoming material. Simultaneously, the recycling path is directly determined by the visual inspection result; the recycling process only needs to perform the corresponding operation based on the classification type, establishing a direct correspondence between the classification result and the recycling path.

[0065] In this embodiment, the corresponding processing steps for various types of unthreshed grains are determined using a classification control device used in the field of agricultural product processing for material identification and diversion. This classification control device is a conventional existing equipment, typically including a data processing unit, a classification control unit, a conveying control unit, and a diversion execution mechanism, used to control different materials to enter their corresponding processing paths based on detection results. This embodiment does not limit the specific structure of the classification control device.

[0066] In this embodiment, the process of determining the corresponding steps for various types of unthreshed kernels includes: Based on the visual inspection results, the integrity of the outer shell, the state of the shell-kernel bond, and the amount of residual edges of each unthreshed kernel are obtained, and the characteristic parameters are sent to the classification control unit. At the same time, the detection results of the shell breakage state are obtained as the basis for classification correction.

[0067] When the shell integrity is higher than the high integrity threshold and the residual amount of edges is higher than the high edge residual threshold, the classification control unit determines that the corresponding unthreshed kernel is of the uncracked type, indicating that the shell integrity of the current kernel is relatively high and the grinding and edge removal effect is insufficient. When the shell integrity is within the medium integrity threshold range and the shell-kernel gap is lower than the shell-kernel gap threshold, the classification control unit determines that the corresponding unthreshed kernel is of the cracked but not threshed type, indicating that the shell of the current kernel has cracked but the connection between the shell and kernel is still relatively strong. When the shell integrity is lower than the low integrity threshold and the residual amount of edges is lower than the low edge residual threshold, the classification control unit determines that the corresponding unthreshed kernel is of the broken shell and adhered type, indicating that the shell of the current kernel is broken but the broken shell pieces are still attached to the kernel surface.

[0068] The classification results are corrected based on the shell breakage state detection results. Specifically, when the shell breakage state is insufficient, if the visual inspection result shows that the shell integrity is high but it is judged as cracked but not detached, the classification control unit corrects the grain type to uncracked. When the shell breakage state is excessive, if the visual inspection result shows that the residual amount of edges is low but it is judged as cracked but not detached, the classification control unit corrects the grain type to broken shell adhered, in order to avoid misclassification caused by a single visual feature.

[0069] In this embodiment, the high integrity threshold, medium integrity threshold range, low integrity threshold, high angular residue threshold, low angular residue threshold, and husk-kernel gap threshold are obtained by statistical analysis based on incompletely hulled grain samples of the same variety of high-flavonoid buckwheat obtained under normal hulling conditions. Specifically, the distribution range of husk integrity, angular residue, and husk-kernel gap corresponding to different types of incompletely hulled grains is statistically analyzed, and the corresponding thresholds are determined based on the distinguishing boundaries of characteristic parameters between different types of samples.

[0070] The shunting actuator is controlled based on the classification result output by the classification control unit, wherein: In response to the determination that the kernels are not cracked and not fully threshed, the conveying control unit controls the return conveyor belt to switch to the pre-treatment return path, so that the corresponding kernels are returned to the feed inlet of the pre-treatment process, and the heating, pressurizing, holding and depressurizing processes are re-executed to further weaken the shell-kernel bond. In response to the determination that the kernels are cracked but not completely thawed, the conveying control unit controls the return conveyor belt to switch to the rubbing and returning path, so that the corresponding kernels are returned to the flexible rubbing and returning process and the rubbing and returning process is repeated to use the existing cracks to promote further separation of the shell and kernel. In response to the determination that the kernels are not completely removed due to the presence of broken shells, the conveying control unit controls the return conveyor belt to switch to the grinding return path, so that the corresponding kernels are returned to the grinding and de-edge removal process and the grinding process is repeated to remove the residual broken shells attached to the kernel surface.

[0071] Specifically, this invention uses both visual inspection results and shell breakage state detection results as classification criteria. The classification of incompletely threshed grains is determined by both the external characteristics of the shell and the actual processing quality of the grinding process. When these two factors are inconsistent, the shell breakage state detection result is used to correct the classification. This ensures that the final classification reflects the actual state of the material rather than solely relying on the external characteristics of the shell. Simultaneously, incompletely threshed grains are returned to the pretreatment, rolling, and grinding processes respectively, categorized into three types: uncracked, cracked but not threshed, and shell-clamped. This allows each type of incompletely threshed grain to be sent back to the corresponding reprocessing process based on its specific reason for not being threshed. Uncracked grains are returned to pretreatment to strengthen the weakened shell-kernel bond; cracked but not threshed grains are returned to rolling to complete shell-kernel separation; and shell-clamped grains are returned to grinding to remove residual shell fragments. This establishes a correspondence between the return path and the reprocessing function, enabling effective reprocessing of each type of incompletely threshed grain in a single return cycle.

[0072] In this embodiment, the adjustment of the temperature and pressure pretreatment parameters, grinding parameters, and rubbing parameters is performed using a process parameter control device. This process parameter control device is a conventional control device used in the agricultural product processing field for adjusting production process parameters. It typically includes a data processing unit, a parameter adjustment unit, and an equipment control unit, used to generate parameter adjustment instructions based on the detection results and control the corresponding actuators to adjust the operating parameters. This embodiment does not limit the specific structure of the process parameter control device.

[0073] In this embodiment, the process of adjusting the temperature and pressure pretreatment parameters, grinding parameters, and rolling parameters includes: After visual inspection and return path allocation are completed, the number of unthreshed kernels of each type is counted by the classification control unit, and the proportion of unthreshed kernels of uncracked type, cracked but not threshed type and broken shell stuck type is calculated to obtain the proportion of each type of unthreshed kernels.

[0074] The percentage of unthreshed grains of each type is sent to the parameter adjustment unit and compared with the corresponding preset threshold.

[0075] In response to the proportion of uncracked shells exceeding a first preset threshold, the parameter adjustment unit determines that the weakening of the shell-core bonding force during the pretreatment stage is insufficient and generates a temperature and pressure pretreatment parameter adjustment command. The adjustment command is sent to the control unit of the temperature and pressure pretreatment device. The pressure adjustment unit extends the pressure holding time, or the cycle execution unit increases the number of cycles of heating, pressurizing, and depressurizing, thereby enhancing the weakening effect of temperature and pressure on the shell-core bonding interface.

[0076] In response to the fact that the proportion of cracked but unseparated shells is higher than the second preset threshold, the parameter adjustment unit determines that the shearing effect provided by the rubbing stage is insufficient, and generates a rubbing parameter adjustment command. The adjustment command is sent to the control unit of the flexible rubbing device. The distance between the two rubbing components is changed by adjusting the rubbing gap adjustment mechanism, or the speed ratio of the two rubbing components is changed by adjusting the drive control unit, so as to improve the shell-shell separation effect.

[0077] In response to the fact that the proportion of shell fragments adhering to the kernel is higher than the third preset threshold, the parameter adjustment unit determines that the weakening of the shell layer during the grinding stage is insufficient, and generates a grinding parameter adjustment command. The adjustment command is sent to the control unit of the grinding device, and the interaction depth between the grinding component and the kernel is changed by adjusting the grinding depth adjustment mechanism to reduce the residual shell fragments adhering to the kernel surface.

[0078] In this embodiment, the first preset threshold, the second preset threshold, and the third preset threshold are determined based on the statistical distribution of the proportion of various types of unhulled grains in multiple batches of production under stable hulling conditions for the same variety of high-flavonoid buckwheat. Specifically, the proportions of uncracked, cracked but not hulled, and broken-hulled and stuck-on unhulled grains are obtained respectively, and the corresponding preset thresholds are determined according to the normal fluctuation range of the corresponding type proportions when the preset hulling effect and kernel integrity requirements are met, so that the parameter adjustment triggering conditions match the normal fluctuation state in the actual production process.

[0079] Specifically, this invention uses statistical analysis of the percentage of various types of unthreshed kernels to indicate the processing quality of each step by whether the percentage exceeds a threshold. A high percentage of uncracked kernels indicates insufficient weakening of the shell-kernel bond during pretreatment; a high percentage of cracked but unthreshed kernels indicates insufficient shearing force during the rolling process to completely peel off the cracked shells; and a high percentage of kernels with adhered broken shells indicates uneven grinding resulting in residual broken shells. Each of these three types corresponds to a processing quality defect in one step. This allows for the identification of problematic steps directly indicated by the percentage of each type, eliminating the need to check each step individually to pinpoint the source of the problem. Furthermore, when the percentage of different types exceeds the threshold, parameter adjustment measures are triggered for their respective steps, ensuring that the direction of parameter adjustment directly corresponds to the process problem reflected by that type. When the percentage of uncracked kernels is high, the holding time is extended and the number of cycles is increased to enhance the weakening effect of the pretreatment stage; when the percentage of cracked but unthreshed kernels is high, the rolling gap and rolling speed ratio are adjusted to enhance the shearing force; and when the percentage of kernels with adhered broken shells is high, the grinding depth is increased to eliminate unevenness. This allows the processing intensity of each step to adaptively adjust with changes in the material state.

[0080] In this embodiment, the drying temperature limit and target moisture content are determined using a drying parameter control device. This device is a conventional control equipment used in the agricultural product processing field for controlling low-temperature drying of materials. It typically includes a temperature detection unit, a humidity detection unit, a heating control unit, an airflow adjustment unit, and a control unit, used to adjust the temperature and drying time during the drying process according to the material's condition. This embodiment does not limit the specific structure of the drying parameter control device.

[0081] In this embodiment, the process of determining the drying temperature limit and the target moisture content includes: The buckwheat kernels obtained after multi-stage separation were sampled, and the moisture content of the samples was detected by a moisture content testing device to obtain the initial moisture content of the current batch of buckwheat kernels.

[0082] A programmed temperature rise test was conducted on buckwheat kernel samples. During the temperature rise, the change in sample mass was continuously monitored. The thermal degradation initiation temperature of flavonoids was determined by combining the flavonoid content detection results. The thermal degradation initiation temperature was used as the drying temperature limit to limit the maximum allowable temperature in the subsequent drying process, so that the drying process is always within the thermal stability range of flavonoids.

[0083] The target moisture content is determined based on the difference between the initial moisture content and the preset safe storage moisture content threshold. Specifically, if the initial moisture content is higher than the safe storage moisture content threshold, the safe storage moisture content threshold is used as the target moisture content. If the initial moisture content is not higher than the safe storage moisture content threshold, it is determined that the buckwheat kernels do not need further drying.

[0084] In this embodiment, the preset safe storage moisture content threshold is determined based on the test results of moisture content change of buckwheat kernels under normal storage conditions. By obtaining storage stability data of buckwheat kernels under different moisture content conditions, the maximum moisture content corresponding to the requirement that no mold or quality deterioration occurs during the storage period is used as the safe storage moisture content threshold.

[0085] In this embodiment, the low-temperature drying is carried out using low-temperature drying equipment used for grain drying in the field of agricultural product processing. This low-temperature drying equipment is a conventional, existing device, typically including a heating module, a circulating air module, a temperature detection module, and a control module, used for constant-temperature drying of the material. This embodiment does not limit the specific structure of the low-temperature drying equipment.

[0086] The determined drying temperature limit and target moisture content are sent to the control module of the low-temperature drying equipment. The control module generates drying control commands. The temperature inside the drying chamber is acquired in real time by the temperature detection module, and the output power of the heating module is controlled according to the relationship between the detected temperature and the drying temperature limit to ensure that the drying temperature does not exceed the drying temperature limit. The airflow circulation inside the drying chamber is maintained by adjusting the operation of the circulating air module to promote the migration of moisture inside the buckwheat kernels.

[0087] During the drying process, the control module acquires the moisture content detection results of the buckwheat kernels according to the preset detection cycle, compares the real-time moisture content with the target moisture content, and generates a stop drying command when the real-time moisture content reaches the target moisture content. This controls the low-temperature drying equipment to stop heating and air supply, and outputs the dried buckwheat kernels to the cooling and packaging process.

[0088] Specifically, this invention solves the problem of flavonoid degradation in some batches of buckwheat kernels and low drying efficiency in others due to differences in thermal stability, by pre-determining the thermal degradation temperature of flavonoids in the current batch of material and using it as the upper limit of the drying temperature. This ensures that the drying temperature limit is determined by the thermal stability of the current batch of material rather than a fixed value, thus enabling each batch of drying to be completed below its respective thermal degradation temperature. Furthermore, by setting the target moisture content as a safe storage moisture content threshold and determining whether and to what extent drying is needed based on the initial moisture content, the drying process adaptively determines whether to start and the endpoint target under different initial moisture contents. In addition, the drying temperature is monitored in real time and the moisture content is sampled periodically during the drying process, ensuring that the drying process simultaneously meets the requirements of temperature constraints and moisture content control. Therefore, in each batch of drying, it is ensured that flavonoids do not undergo thermal degradation while the moisture content is controlled within a safe storage range.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for directional dehulling of buckwheat seeds, characterized in that, include: High-flavonoid buckwheat seeds were selected for particle size classification, and the moisture content of each particle size fraction was detected. Based on the moisture content of each particle size, the temperature and pressure pretreatment parameters for expanding the gap between the kernel and husk of the graded grains placed in a sealed container are determined, so as to carry out temperature and pressure pretreatment and obtain pretreated samples. Based on the particle size classification results, grinding parameters are determined to perform grinding and edge removal on the pretreated sample to obtain a ground sample. Buckwheat hull powder generated during the grinding and edge removal process is collected, and the particle size distribution characteristics of the buckwheat hull powder are detected to obtain the shell breakage state detection results. Based on the particle size classification results, the rolling parameters are determined to perform flexible rolling on the grinding sample to obtain the rolled mixture. Multi-stage separation is performed based on the particle size differences between buckwheat kernels, buckwheat hulls, and unthreshed grains in the mixture. Visual inspection is then performed on the separated unthreshed grains in conjunction with the results of the hull breakage detection to obtain visual inspection results. Based on the visual inspection results and the shell breakage state inspection results, the corresponding processes for various types of unthreshed kernels are determined for reprocessing. At the same time, the temperature and pressure pretreatment parameters, grinding parameters, and rolling parameters are adjusted according to the proportion of unthreshed kernels and the shell breakage state. Based on the moisture content of the buckwheat kernels obtained after multi-stage separation and the preset thermal degradation temperature, the drying temperature limit and target moisture content are determined, and the separated buckwheat kernels are dried to the target moisture content before packaging.

2. The method for directional dehulling of buckwheat seeds according to claim 1, characterized in that, The process of determining the temperature and pressure pretreatment parameters includes: Based on the heat softening characteristics of high-flavonoid buckwheat hulls and the thermal degradation temperature of flavonoids, the heating temperature for pretreatment was determined. Based on the moisture content of each particle size, the pressurization pressure and holding time are determined; Based on the particle size classification results, the number of cycles is determined; The heating temperature, pressurization pressure, holding time, and number of cycles are used as temperature and pressure pretreatment parameters.

3. The method for directional dehulling of buckwheat seeds according to claim 1, characterized in that, The process of determining grinding parameters includes: Based on the particle size classification results, the average particle size of each particle size class is obtained; Based on the average particle size of each particle size, determine the grinding clearance corresponding to each particle size; The grinding depth corresponding to each particle size was determined based on the thickness of the high-flavonoid buckwheat hull. The grinding clearance and grinding depth corresponding to each grain size are used as grinding parameters.

4. The method for directional dehulling of buckwheat seeds according to claim 1, characterized in that, The process of detecting the shell fracture state includes: Buckwheat hull powder generated during the grinding and de-edge-removing process was collected as a test sample. The test sample was sieved to obtain the mass percentage of buckwheat hull powder with different particle size ranges, and the particle size distribution test results were obtained. When the mass percentage of fine powder exceeds the fine powder threshold, the shell fragmentation state is determined to be excessively fragmented. In response to the fact that the mass percentage of coarse powder exceeds the coarse powder threshold, the shell fragmentation state is determined to be insufficient.

5. The method for directional dehulling of buckwheat seeds according to claim 1, characterized in that, The process of determining the rolling parameters includes: Based on the particle size classification results, the average particle size of each particle size class is obtained; The rubbing gap for each particle size is determined based on the average particle size of the material in each particle size; The rolling speed ratio corresponding to each particle size was determined based on the binding force of high-flavonoid tartary buckwheat hull kernels. The rubbing gap and rubbing speed ratio corresponding to each particle size are used as rubbing parameters.

6. The method for directional dehulling of buckwheat seeds according to claim 1, characterized in that, The process of multi-stage separation of the mixture includes: Based on the specific gravity difference between buckwheat hulls, buckwheat kernels, and unthreshed grains, the mixture after hulling and crushing was separated by air separation to separate the buckwheat hulls and obtain the remaining material after air separation. Based on the particle size difference among the remaining materials after air separation, they are screened and separated to separate buckwheat kernels, resulting in unthreshed grains. The unthreshed grains are sent to the visual inspection process as the objects of visual inspection.

7. The method for directional dehulling of buckwheat seeds according to claim 1, characterized in that, The process of visually inspecting unthreshed kernels includes: Images of unthreshed grains were collected. Based on the image, characteristic parameters were extracted from the shell integrity, kernel-shell bonding state, and residual amount of unequal-threshed kernels. The visual detection result is determined based on the aforementioned feature parameters.

8. The method for directional dehulling of buckwheat seeds according to claim 1, characterized in that, The process of determining the appropriate steps for each type of unthreshed kernel includes: Based on the visual inspection results and the shell breakage state inspection results, the unthreshed kernels are divided into three types: uncracked, cracked but not threshed, and broken shells stuck together. Uncracked types are returned to the pretreatment process, cracked but not detached types are returned to the flexible rolling process, and types with broken shells adhering to the shell are returned to the grinding and de-edge removal process.

9. The method for directional dehulling of buckwheat seeds according to claim 1, characterized in that, The process of adjusting the temperature and pressure pretreatment parameters, grinding parameters, and rolling parameters includes: The percentage of each type of unthreshed grain was statistically analyzed. If the proportion of uncracked cells exceeds the first preset threshold, the holding time is extended or the number of cycles is increased. In response to a higher-than-preset threshold for the proportion of cracked but undeformed parts, adjust the rubbing gap or rubbing speed ratio. In response to the proportion of shell fragments adhering to the surface exceeding the third preset threshold, the grinding depth is increased.

10. The method for directional dehulling of buckwheat seeds according to claim 1, characterized in that, The process of determining drying temperature limits and target moisture content includes: The moisture content of the buckwheat kernels obtained after multi-stage separation was measured. The thermal degradation temperature of flavonoids in high-flavonoid buckwheat was obtained, and the drying temperature limit was determined based on the thermal degradation temperature. The target moisture content is determined based on the moisture content and the preset safe storage moisture content threshold. The drying temperature limit and the target moisture content are used as drying parameters. The buckwheat kernels are dried according to the drying parameters, and the drying temperature is controlled not to exceed the drying temperature limit during the drying process. Drying is terminated when the moisture content of the buckwheat kernels reaches the target moisture content.

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