Nanometer quick-freezing fresh-keeping method based on superposed space electric field

Abstract

The invention provides a nanometer quick-freezing fresh-locking method based on a superposed space electric field, and relates to the technical field of freezing fresh-locking, and the method comprises the following steps: obtaining a three-dimensional space arrangement of muscle fibers in a nanometer quick-freezing liquid, and identifying a fiber arrangement included angle and a fiber coverage density of the muscle fibers, collecting the initial electric field direction of the superposition space electric field and the polarization intensity of each area to obtain a polarization intensity mean value; determining a one-way electric field coverage rate according to whether the fiber arrangement included angle exceeds a preset one-way electric field coverage range threshold value or not, and determining polarization intensities of fibers with different orientations according to the one-way electric field coverage rate and the fiber coverage density; and an electric field switching period is generated based on the adjusted polarization intensity distribution, the difference value change trend of the energy storage value in the fiber and the energy storage value in the fiber gap after the electric field switching period is executed is analyzed, the balance degree of energy storage inside and outside the fiber is evaluated, and whether cold energy storage exceeds a preset range or not is monitored.

Description

Technical Field

[0001] This invention relates to the field of freezing and freshness-preserving technology, and in particular to a nano-rapid freezing and freshness-preserving method based on superimposed spatial electric fields. Background Technology

[0002] In the field of food quick-freezing technology, researching innovative methods to improve freezing effects and lock in the freshness of ingredients is crucial. This area directly relates to the maintenance of food quality and the protection of nutritional value, and has a profound impact on the modern food industry and consumer experience. Especially in the processing of high-end ingredients, the quality of quick-freezing technology often determines the market competitiveness of the final product. However, existing quick-freezing methods often reveal shortcomings when dealing with complex food structures. Many technologies focus more on overall freezing speed in their design, neglecting the impact of differences in the internal microstructure of the ingredients on the freezing effect. This neglect leads to uneven freezing when processing ingredients with complex textures, thus affecting the stability of the food's taste and quality. A deeper technical challenge lies in how to balance the energy distribution of the freezing liquid under the influence of an electric field with the compatibility with the internal structure of the ingredients. As an auxiliary freezing method, the effect of the electric field is highly dependent on its relationship with the internal fiber arrangement of the ingredients. If the direction of the electric field does not match the fiber structure, it will lead to an imbalance in the distribution of energy within and between the fibers, thus affecting the formation of ice crystals during the freezing process. For example, when processing meat, the meat fibers are often arranged in multiple directions. If the direction of the electric field is fixed, the gaps between the fibers in some areas may not be able to form uniform ice crystals due to insufficient energy, while in other areas, the ice crystals may grow in a chaotic direction due to excessive energy concentration, resulting in uneven texture of the meat after thawing.

[0003] Therefore, how to dynamically adjust the mode of electric field application during freezing to adapt to the complex arrangement of the internal fiber structure of food and achieve a balanced distribution of energy within the fibers and between the gaps has become a key issue in improving the quick-freezing effect and food quality. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields, the method comprising: The three-dimensional spatial arrangement of muscle fibers in nano-freezing fluid was obtained, the fiber arrangement angle and fiber coverage density of muscle fibers were identified, the preliminary electric field direction of the superimposed spatial electric field and the polarization intensity of each region were collected, and the average polarization intensity was obtained. The unidirectional electric field coverage is determined based on the fiber arrangement angle, and the polarization intensity of fibers with different orientations is determined based on the unidirectional electric field coverage and fiber coverage density. By comparing the polarization intensity of fibers with different orientations with the mean polarization intensity, regions with polarization intensity lower than the mean are identified as gap regions with low energy storage. The energy storage difference value of the gap regions with low energy storage is extracted, and the energy storage value inside the fiber and the energy storage value between the fibers are identified. The electric field rotation angle is identified by the deviation angle between the gap region with low energy storage and the initial electric field direction. The polarization intensity distribution of the gap region with low energy storage is adjusted according to the electric field rotation angle. The supercooling characteristics of the nano-freezing liquid are used to store cold energy without forming ice crystals. The electric field switching cycle is generated based on the adjusted polarization intensity distribution. The trend of the difference between the energy storage value inside the fiber and the energy storage value between the fiber gaps after the execution of the electric field switching cycle is analyzed to evaluate the degree of energy storage balance inside and outside the fiber and monitor the cold energy storage. When the energy storage inside and outside the fiber is balanced and the cold storage exceeds the range, the food crystallizes instantly. After the polarization intensity distribution is adjusted, the polarization intensity gradient direction of each region is extracted. Based on the spatial correspondence between the polarization intensity gradient direction and the fiber arrangement angle, the orientation angle of ice crystal growth is identified. Matching the orientation angle of ice crystal growth with the required direction of ice crystal growth, identifying the deviation of the ice crystal growth angle, adjusting the electric field switching cycle according to the deviation of the ice crystal growth angle, determining the uniform polarization intensity of the nano-freezing liquid in the fiber gap, and controlling the directional growth of ice crystals along the fiber gap direction for cryopreservation at freezing temperature.

[0005] Furthermore, the process of obtaining the three-dimensional spatial arrangement of muscle fibers in the nano-freezing liquid, identifying the fiber arrangement angle and fiber coverage density, acquiring the preliminary electric field direction of the superimposed spatial electric field and the polarization intensity of each region, and obtaining the average polarization intensity includes: An ultrasonic scanner was used to scan muscle tissue immersed in a nano-freezing liquid layer by layer to obtain cross-sectional image data. The fiber contour coordinates in the cross-sectional image were extracted by an image recognition algorithm. The three-dimensional spatial trajectory of the fiber bundle was constructed according to the spatial connection relationship of the corresponding fiber contour coordinates between adjacent layers to obtain the three-dimensional spatial arrangement of muscle fibers. For the three-dimensional spatial arrangement of muscle fibers, the angle between the central axes of adjacent fiber bundles was calculated, the number of fiber bundles in each fiber group per unit volume was counted, and the fiber coverage density was calculated. An array of electrode plates is arranged in the quick-freezing device according to the fiber coverage density. A uniform electric field is applied as the initial electric field direction. A Hall effect sensor probe is used to measure the local electric field intensity value in different fiber group regions, and the polarization intensity data of each measurement point is recorded. The weighted average value of all measurement points is calculated using the polarization intensity data to obtain the average polarization intensity.

[0006] Furthermore, the step of determining the unidirectional electric field coverage based on the fiber arrangement angle, and determining the polarization intensity of fibers with different orientations based on the unidirectional electric field coverage and fiber coverage density, includes: Obtain the direction of the principal axis of each fiber bundle in the three-dimensional spatial arrangement of muscle fibers, calculate the angle between the principal axis of the fiber bundle and the direction of the initial unidirectional electric field, and calculate the ratio of the number of fibers that can be covered to the total number of fibers to determine the coverage rate of the unidirectional electric field. Based on the unidirectional electric field coverage rate, fiber coverage density data of uncovered fiber areas are extracted, and polarization intensity adjustment coefficients for different areas are obtained through function mapping. The initial polarization intensity value of each region is corrected by the polarization intensity adjustment coefficient, and the polarization intensity value of each oriented fiber under the current electric field is calculated by combining the dielectric constant of different oriented fiber groups, thereby determining the polarization intensity of different oriented fibers.

[0007] Furthermore, the step of comparing the polarization intensity of fibers with the average polarization intensity to identify regions with polarization intensity lower than the average, and determining these regions as gap regions with low energy storage, includes: The polarization intensity data of fibers with different orientations are obtained and compared point by point with the average polarization intensity. The region is marked as a low polarization region. Based on the positional relationship between the low polarization region and the spatial arrangement of the fibers, the low polarization region located between the fiber bundles is determined to be a gap region with low energy storage.

[0008] Furthermore, the identification of the electric field rotation angle by the deviation angle between the gap region with low energy storage and the initial electric field direction includes: Based on the spatial distribution of the gap region with low energy storage, the three-dimensional spatial arrangement of muscle fibers is obtained. For the three-dimensional spatial arrangement of muscle fibers, the main direction vector of fiber arrangement in the gap region is extracted. The angle between the main direction vector and the initial electric field direction vector is calculated as the deviation angle. The electric field rotation angle is determined based on the deviation angle.

[0009] Furthermore, the process of generating an electric field switching cycle based on the adjusted polarization intensity distribution, analyzing the trend of the difference between the energy storage value inside the fiber and the energy storage value between the fiber gaps after the execution of the electric field switching cycle, evaluating the degree of energy storage balance inside and outside the fiber, and monitoring cold energy storage includes: Based on the adjusted polarization intensity distribution data, the time required for the polarization intensity in different regions to reach stability is calculated. The maximum value of the stability time in each region is taken as the basic period length. Multiple switching time points are set within the basic period to generate an electric field switching period that includes the switching time and duration. The electric field switching cycle control electrode plate array is used to record the energy storage value inside the fiber and the energy storage value between the fibers at each switching moment. The difference between the two is calculated to form a difference sequence. The difference sequence is then accumulated and averaged over time to obtain the trend of difference change. The ratio of the current energy storage value within the fiber to the energy storage value between the fiber gaps is calculated based on the trend of the difference change as the degree of energy storage balance. The total cold storage value is calculated by combining the energy storage balance with the energy storage value within the fiber and the energy storage value between the fibers.

[0010] Furthermore, when the energy storage inside and outside the fiber is balanced and the cold storage exceeds the range, the food crystallizes instantaneously. After adjusting the polarization intensity distribution, the polarization intensity gradient direction of each region is extracted. Based on the spatial correspondence between the polarization intensity gradient direction and the fiber arrangement angle, the orientation angle of ice crystal growth is identified, including: Monitor the energy storage equilibrium state and cold storage value inside and outside the fiber, remove the electric field to make the food crystallize instantly, and record the polarization intensity value and spatial coordinates of each region at the moment of crystallization triggering. Based on the polarization intensity value and spatial coordinates, the polarization intensity difference and distance ratio between adjacent measurement points are calculated to obtain the polarization intensity gradient magnitude at each point. The gradient direction vector is determined by the components of the gradient on the three-dimensional coordinate axes. Obtain the angle between the gradient direction vector and the fiber arrangement direction at the corresponding position; identify the orientation angle of ice crystal growth in each region by using the angle between the gradient direction vector and the fiber arrangement direction at the corresponding position and the three-dimensional spatial arrangement data of the fibers.

[0011] Furthermore, the process of matching the orientation angle of ice crystal growth with the required ice crystal growth direction, identifying ice crystal growth angle deviations, adjusting the electric field switching cycle based on the ice crystal growth angle deviations, determining the uniform polarization intensity of the nano-freezing liquid in the fiber gaps, and controlling the directional growth of ice crystals along the fiber gap direction for cryopreservation at freezing temperature includes: Obtain the orientation angle data of ice crystal growth, compare it point by point with the growth direction along the fiber gap, calculate the angle difference as the deviation value, and statistically analyze the spatial distribution of the deviation points to obtain the angle deviation distribution map. Based on the angle deviation distribution map, the location of the deviation region is extracted, the electric field switching cycle parameter corresponding to the region is analyzed, the polarization establishment rate of the region is changed by adjusting the switching time interval, the polarization intensity gradient direction is corrected, and the adjusted electric field switching cycle is generated. The electric field is reapplied using the adjusted electric field switching cycle, and the polarization intensity value at each point in the fiber gap is monitored. The ratio of the standard deviation to the average value of the polarization intensity is calculated.

[0012] Furthermore, the step of extracting the energy storage difference value of the gap region with low energy storage, and identifying the energy storage value within the fiber and the energy storage value between the fibers, includes: For the gap region with low energy storage, calculate the difference between the polarization intensity at each point in the gap region and the mean polarization intensity, and take the absolute value of the difference as the energy storage difference value. By using the distribution map of the interstitial region, the gradient change detection method is used to identify the abrupt boundary of polarization intensity. The high polarization intensity region inside the boundary is determined to be the fiber interior, and the low polarization intensity region outside the boundary is determined to be the fiber interstitial region. The average value of polarization intensity at the measurement points inside the fiber and the fiber interstitial region is calculated respectively.

[0013] Furthermore, the step of adjusting the polarization intensity distribution in the gap region with low energy storage according to the electric field rotation angle, and utilizing the supercooling characteristics of the nano-freezing liquid for cold storage without forming ice crystals, includes: The phase difference of each electrode in the electrode plate array is adjusted according to the electric field rotation angle. The electrode plate array adopts a multi-phase power supply method. The rotation of the electric field direction is achieved by adjusting the phase relationship between each phase, so that the electric field direction is parallel to the fiber direction in the gap region, forming a rotating electric field, and the adjusted electric field configuration parameters are obtained. Using the adjusted electric field configuration parameters, a rotating electric field is applied to the gap region where the energy storage is low. The change in polarization intensity of the nano-frozen liquid in the gap region is monitored to keep the water molecules in the nano-frozen liquid in an orderly arrangement. Through the orderly arrangement of water molecules, the temperature of the gap region is controlled to be lower than the freezing point but higher than the nucleation temperature, thus maintaining the supercooled liquid state.

[0014] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: This invention discloses a nano-fast freezing and freshness-locking method based on superimposed spatial electric fields. Addressing the challenges of controlling ice crystal growth direction, uneven cold storage, and poor freshness-locking effects during food fast freezing, this invention integrates muscle fiber arrangement angle analysis, polarization intensity distribution adjustment, and electric field switching cycle optimization to form a logically interconnected solution. First, the invention obtains fiber arrangement and electric field parameters, identifies regions with low energy storage, and adjusts the electric field rotation angle to balance the polarization intensity distribution. Then, it generates an electric field switching cycle, monitors the degree of energy storage balance and cold storage status, and finally dynamically adjusts the electric field cycle based on the ice crystal growth angle deviation to control the directional growth of ice crystals along the fiber gaps. By precisely controlling the spatial relationship between the electric field and fibers, this invention achieves uniform cold distribution and directional ice crystal growth during freezing, significantly improving the freshness-locking effect of food and providing innovative assurance for fast freezing technology. Attached Figure Description

[0015] Figure 1 This is a flowchart of a nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields according to the present invention.

[0016] Figure 2 This is a schematic diagram of a nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields according to the present invention.

[0017] Figure 3 This is another schematic diagram of a nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields according to the present invention. Detailed Implementation

[0018] To further understand the content of this invention, a detailed description of the invention is provided in conjunction with the accompanying drawings and embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0019] like Figures 1-3 This embodiment of a nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields may specifically include: Step S101: Obtain the three-dimensional spatial arrangement of muscle fibers in the nano-freezing liquid, identify the fiber arrangement angle and fiber coverage density of muscle fibers, collect the preliminary electric field direction of the superimposed spatial electric field and the polarization intensity of each region, and obtain the average polarization intensity.

[0020] An ultrasonic scanner is used to scan muscle tissue immersed in a nano-freezing liquid layer by layer, acquiring cross-sectional image data at preset depth intervals. An image recognition algorithm is used to extract fiber contour coordinates from the cross-sectional images. Based on the spatial connection relationship of corresponding fiber contour coordinates between adjacent layers, a three-dimensional spatial trajectory of the fiber bundles is constructed, resulting in the three-dimensional spatial arrangement of muscle fibers. For this three-dimensional spatial arrangement of muscle fibers, the angle between the central axes of adjacent fiber bundles is calculated. Based on the comparison between the angle size and a preset angle threshold, the fiber bundles are classified into parallel fiber groups, intersecting fiber groups, or perpendicular fiber groups. The number of fiber bundles per unit volume in each fiber group is counted, and the fiber coverage density is calculated. The fiber coverage density affects the local electric field distribution; the electric field strength is positively correlated with the fiber coverage density. Higher density areas require a higher intensity electric field to achieve sufficient polarization. Based on the fiber coverage density, an electrode plate array is arranged within the quick-freezing device. A uniform electric field of preset intensity is applied as the initial electric field direction. A Hall effect sensor probe is used to measure the local electric field intensity in different fiber group regions, and the polarization intensity data at each measurement point is recorded. The average polarization intensity is obtained by calculating the weighted average of all measurement points using the polarization intensity data. The weights are determined based on the fiber coverage density of the area where each measurement point is located.

[0021] Specifically, in one embodiment, an ultrasonic scanner uses a phased array probe to scan muscle tissue immersed in a nano-freezing liquid. In this embodiment, the nano-freezing liquid refers to a stable supercooled aqueous solution formed by dispersing conductive nanoparticles in pure water. The conductive nanoparticles include alumina or carbon nanotubes, with a volume fraction of 0.1% to 5%. This liquid can maintain a supercooled state for a long period under the action of an applied electric field. The phased array probe comprises multiple piezoelectric crystal elements, and the electronic focusing and deflection of the sound beam are achieved by controlling the excitation delay of each element. During the scanning process, the probe emits ultrasonic pulses with a frequency of 5MHz to 10MHz. The ultrasonic waves generate reflected echoes at the interface between the muscle fibers and the nano-freezing liquid. Due to the difference in acoustic impedance between the muscle fibers and the nano-freezing liquid, the intensity of the reflected echo is positively correlated with the fiber density. After receiving the echo signal, the probe adjusts the gain of the echoes at different depths through a time gain compensation circuit to compensate for the attenuation effect of the ultrasonic waves in the tissue.

[0022] Specifically, the image recognition algorithm uses an edge detection operator to process the cross-sectional image of each layer. First, a Gaussian filter is applied to reduce image noise, and then the Sobel operator is used to calculate the gradient magnitude and direction of the image. When the gradient magnitude exceeds a preset threshold, the point is determined to be a fiber contour boundary point. For continuous boundary points, eight-neighborhood connectivity analysis is used to form a closed contour. After obtaining the fiber contour of multiple cross-sections, the spatial positions of corresponding contour points between adjacent layers are fitted using the least squares method to establish the three-dimensional spatial trajectory equation of the fiber bundle. The trajectory equation is parametrically represented, where parameter t represents the position along the fiber length direction, and x(t), y(t), and z(t) represent the positions of the fiber central axis in the three-dimensional coordinate system, respectively.

[0023] For example, in the quick-freezing process of beef tissue, muscle fibers exhibit a typical bundled arrangement. Each fiber bundle has a diameter of approximately 50 to 100 micrometers, and the fiber bundles are separated by connective tissue. In cross-sectional images acquired by ultrasonic scanning, the fiber bundles appear as elliptical or irregular polygonal hyperechoic regions, while the connective tissue appears as a hypoechoic linear structure. By analyzing 20 to 30 consecutive layers of cross-sectional images, a complete three-dimensional fiber network structure was constructed. This three-dimensional structural data contains the spatial coordinates, orientation angle, and curvature information of each fiber, providing basic data for subsequent fiber classification and electric field configuration.

[0024] In one possible implementation, the fiber angle is calculated based on vector analysis. For any two adjacent fiber bundles, several sampling points on their central axes are extracted, and their respective direction vectors are obtained by least squares fitting. The angle between the two direction vectors is calculated using the vector dot product formula. Based on the angle, the fibers are divided into three categories: parallel fiber groups have an angle less than a first preset angle threshold; intersecting fiber groups have an angle between the first and second preset angle thresholds; and perpendicular fiber groups have an angle greater than a second preset angle threshold. Fiber coverage density is defined as the ratio of the sum of the cross-sectional areas of the fibers per unit volume to that volume. This density affects the electric field distribution, enhancing the polarization effect by increasing the local dielectric constant.

[0025] Specifically, fiber coverage density is defined as the ratio of the total cross-sectional area of ​​fibers per unit volume to that volume. This density affects the electric field distribution, enhancing the polarization effect by increasing the local dielectric constant. Specifically, the electric field strength E is directly proportional to the fiber coverage density ρ, which can be expressed as E = k * ρ, where k is a proportionality coefficient determined by the dielectric properties of the nano-freezing liquid and the electrode configuration parameters. This relationship guides the spatial arrangement of the electrode plates, the weighting calculation of the electric field strength in each region, and the adjustment of the polarization intensity compensation coefficient. Specifically, this system adopts an electrode plate array hardware structure, which consists of multiple independent electrode plates. Each electrode plate corresponds to a specific spatial region within the quick-freezing device. Independent control of each region is achieved through an embedded controller, allowing for individual setting of the voltage, frequency, and phase parameters of each electrode plate.

[0026] It should be noted that the arrangement of the electrode plate array must take into account the dielectric properties of the nano-freezing liquid. The nano-freezing liquid contains nanoscale conductive particles, which exhibit polarization under the influence of an electric field. The electrode plates are made of stainless steel, and their surfaces are electrochemically polished to reduce surface roughness and minimize electric field concentration effects. The spacing between the electrode plates is determined based on the volume of the quick-freezing device and the required electric field strength, typically ranging from 10 to 30 centimeters. The applied electric field is an alternating current field with a frequency range of 50 Hz to 1 kHz, and the electric field strength is controlled by adjusting the applied voltage.

[0027] Preferably, the Hall effect sensor's measurement principle is based on the deflection effect of charge carriers in a magnetic field. The sensor contains a semiconductor wafer. When current flows through the wafer and a magnetic field perpendicular to the current direction exists, the charge carriers are deflected by the Lorentz force, generating a potential difference across the wafer. This potential difference is proportional to the magnetic field strength. When measuring polarization intensity, the sensor probe is inserted at different locations within the fiber tissue, and an external magnetic field generator produces a known magnetic field. The voltage change caused by the interaction of the local electric and magnetic fields is measured, and the polarization intensity value is calculated. The polarization intensity data at each measurement point includes magnitude, direction, and phase information.

[0028] For example, during the quick-freezing process of pork tissue, the electric field is refracted and reflected at the interface between the fat and lean meat layers due to the difference in dielectric constants. The fat tissue has a lower dielectric constant, approximately 3 to 5, while the lean meat tissue has a higher dielectric constant, approximately 50 to 80. This difference results in a higher electric field intensity in the fat layer and a lower intensity in the lean meat layer. Three-dimensional distribution data of the polarization intensity were obtained by arranging multiple measurement points at different depths.

[0029] Understandably, the average polarization intensity is calculated using a weighted average method. Considering the differences in fiber density across different regions, regions with higher density are assigned a larger weight, while regions with lower density are assigned a smaller weight. The weighting coefficient is determined based on the ratio of fiber coverage density to the average density. The average polarization intensity calculated using this weighted average method better reflects the overall polarization level, providing a reference benchmark for subsequent electric field optimization adjustments.

[0030] Step S102: Determine the unidirectional electric field coverage rate based on whether the fiber arrangement angle exceeds the preset unidirectional electric field coverage range threshold, and determine the polarization intensity of different oriented fibers based on the unidirectional electric field coverage rate and fiber coverage density.

[0031] The principal axis directions of each fiber bundle in the three-dimensional spatial arrangement of muscle fibers obtained above are acquired. The angle between the principal axis of the fiber bundle and the initial unidirectional electric field direction is calculated. If the angle is less than a preset coverage threshold, the fiber is marked as a coverable fiber. The ratio of the number of coverable fibers to the total number of fibers is calculated to determine the unidirectional electric field coverage rate. The effect of the electric field is judged based on the unidirectional electric field coverage rate. If the coverage rate is lower than a preset standard threshold, the fiber coverage density data of the uncovered fiber area is extracted. Based on the correspondence between coverage rate and density, the polarization intensity adjustment coefficient of different regions is obtained through function mapping. The adjustment coefficient decreases as the coverage rate decreases. The initial polarization intensity value of each region is corrected by the polarization intensity adjustment coefficient. Combined with the dielectric constant of different orientation fiber groups, the polarization intensity value of each orientation fiber under the current electric field is calculated based on the physical relationship between electric field strength, dielectric constant, and polarization intensity to determine the polarization intensity of different orientation fibers.

[0032] Specifically, in one implementation, the fiber principal axis direction is obtained by performing principal component analysis on the three-dimensional spatial arrangement data. Each fiber bundle is represented as a spatial curve in the three-dimensional coordinate system, and its principal axis direction vector is obtained by fitting this curve using the least squares method. The angle between the principal axis direction vector and a preset unidirectional electric field direction vector is calculated using the vector dot product formula, where the cosine of the angle is equal to the product of the two vector dot products divided by the vector magnitudes.

[0033] Specifically, the preset coverage threshold is determined based on the dielectric anisotropy of the nano-freezing liquid. When the angle between the fiber principal axis and the electric field direction is less than 30 degrees, the electric field energy is mainly transmitted along the fiber axis, resulting in a significant polarization effect. When the angle exceeds 60 degrees, the penetration depth of the electric field in the fiber decreases sharply, and the polarization effect is weak. The unidirectional electric field coverage rate is obtained by statistically analyzing the proportion of fibers with angles less than the threshold.

[0034] It should be noted that the calculation of the polarization intensity adjustment coefficient comprehensively considers both coverage and fiber density. In high-density fiber regions, even with a low coverage, the actual polarization intensity remains at a high level due to the electric field coupling effect between fibers. The adjustment coefficient adopts an exponential decay function to achieve a smooth transition. Specifically, when the coverage c is less than 50%, the adjustment coefficient is calculated according to the formula α=exp(-k*(0.5-c)), where α is the adjustment coefficient and k is the decay constant set according to the material properties (usually taken as 2). This function ensures the nonlinear decay characteristic of polarization intensity as coverage decreases. Preferably, the dielectric constants of fibers with different orientations are obtained through experimental determination. The relative dielectric constant ε of parallel-oriented fibers... Approximately 80 for cross-oriented fibers, approximately 65 for cross-oriented fibers, and approximately 45 for perpendicularly oriented fibers. The relationship between polarization intensity P, electric field intensity E, and dielectric constant is expressed by the physical formula P = ε₀(ε₀ + ε₀). -1) E description, where P is the polarization intensity and ε0 is the vacuum permittivity (8.854 × 10⁻⁶). -12 F / m), ε Let be the relative permittivity, and E be the local electric field intensity. By applying an adjustment coefficient to the initial polarization intensity and combining it with the differences in permittivity of each oriented fiber, the actual polarization intensity distribution of each fiber region is finally determined.

[0035] For example, during the quick-freezing process of chicken breast, the muscle fibers are mainly arranged in parallel, with a unidirectional electric field coverage of over 85% and a relatively uniform polarization intensity distribution. However, when processing fish, due to the special structure of the myosarcomere, the fiber arrangement is more complex, requiring regional calculation of polarization intensity based on the fiber orientation characteristics of different parts.

[0036] Step S103: Compare the polarization intensity of different oriented fibers with the average polarization intensity, identify regions with polarization intensity lower than the average value, determine them as gap regions with low energy storage, extract the energy storage difference value of the gap regions with low energy storage, and identify the energy storage value inside the fiber and the energy storage value between the fibers.

[0037] Polarization intensity data of fibers with different orientations are acquired and compared point-by-point with the average polarization intensity. When the polarization intensity of a certain region is lower than a preset threshold of the average, the region is marked as a low-polarization region. Based on the positional relationship between the low-polarization region and the spatial arrangement of the fibers, the low-polarization regions located between fiber bundles are determined to be gap regions with low energy storage. For the gap regions with low energy storage, the difference between the polarization intensity at each point in the region and the average polarization intensity is calculated, and the absolute value of the difference is taken as the energy storage difference value. Based on the magnitude of the energy storage difference value, the regions are divided into three levels: high, medium, and low, generating gap region distribution maps of different energy storage levels. Using the gap region distribution map, a gradient change detection method is used to identify abrupt boundaries of polarization intensity. The high polarization intensity region inside the boundary is determined to be the fiber interior, and the low polarization intensity region outside the boundary is determined to be the fiber gap. The average value of the polarization intensity of all measurement points inside the fiber is calculated as the fiber internal energy storage value, and the average value of the polarization intensity of all measurement points in the fiber gap is calculated as the fiber gap energy storage value.

[0038] Specifically, in one implementation, the comparison between polarization intensity and the mean is performed using the relative deviation method. Considering the influence of unidirectional electric field coverage and fiber coverage density on the polarization effect, the polarization intensity needs to be corrected. Using the mean polarization intensity P0 as a benchmark, the theoretical polarization intensity P = P0 × (C × D) for different oriented fibers is calculated by correcting it through the product of unidirectional electric field coverage C and fiber coverage density D, where P0 is the mean polarization intensity, C is the unidirectional electric field coverage, D is the fiber coverage density, and P is the corrected theoretical polarization intensity. For the actual polarization intensity value at each measurement point, its relative deviation from the corrected theoretical polarization intensity is calculated, i.e., the deviation value divided by the theoretical value yields the deviation rate. When the deviation rate exceeds a preset threshold, the point is marked as an abnormal polarization point. A spatial clustering algorithm connects adjacent abnormal polarization points into regions, forming a preliminary low-polarization region distribution.

[0039] Specifically, the identification of gap regions with low energy storage is based on the three-dimensional spatial arrangement information of the fiber bundles. The fiber bundles are distributed in a cylindrical shape in space, with irregular gap spaces between them. When the spatial coordinates of a low-polarization region fall outside the outer contour of the fiber bundle, the region is determined to be a fiber gap. These gap regions typically exhibit a narrow or sheet-like spatial shape, with significantly lower polarization intensity than the internal fiber regions. The energy storage difference value is obtained by calculating the average difference between the polarization intensity of all measurement points within the gap region and the mean value; this difference value reflects the degree of insufficient energy storage in the gap region.

[0040] It should be noted that the gradient change detection method utilizes the continuous spatial distribution of polarization intensity. Inside the fiber, the polarization intensity changes gradually, with a small gradient value; however, at the boundary between the fiber and the interfiber, the polarization intensity changes abruptly, and the gradient value increases sharply. By setting a gradient threshold, the boundary line of the abrupt change in polarization intensity is identified. The closed region enclosed by the boundary line is the internal region of the fiber, and the region outside the boundary line is the interfiber interstitial region. The energy storage value inside the fiber is obtained by calculating the arithmetic mean of the polarization intensity at all measurement points inside the fiber, reflecting the overall energy storage level of the fiber structure. The energy storage value in the interfiber interstitial region is obtained by averaging the polarization intensity at measurement points within the interfiber interstitial region, reflecting the energy storage state of the interfiber space.

[0041] Preferably, when processing mutton tissue, due to its relatively thick and regularly arranged fiber bundles, there is a significant difference in polarization intensity between the inside and outside of the fibers. The polarization intensity inside the fibers typically reaches more than 1.2 times the average, while the polarization intensity between the fibers is only about 0.6 times the average. By accurately identifying this difference in energy storage distribution, a quantitative basis is provided for subsequent electric field adjustments.

[0042] For example, during the processing of quick-frozen rabbit meat, the muscle fibers exhibit a multi-layered bundle structure, with the interfibrillary spaces rich in connective tissue and fat. These interfibrillary regions have a low dielectric constant, resulting in insufficient polarization response, with the energy storage value being only one-third that of the fiber interior.

[0043] Step S104: Identify the required electric field rotation angle by the deviation angle between the gap region with low energy storage and the initial electric field direction, adjust the polarization intensity distribution of the gap region with low energy storage according to the electric field rotation angle, and use the supercooling characteristics of the nano-freezing liquid to store cold energy without forming ice crystals.

[0044] Based on the spatial distribution of the gap region with low energy storage, and combined with the previously acquired three-dimensional spatial arrangement data of the fibers, the principal direction vector of the fiber arrangement within this gap region is extracted. The angle between the principal direction vector and the initial electric field direction vector is calculated as the deviation angle, and the electric field rotation angle is determined based on the deviation angle. The phase difference of each electrode in the electrode plate array is adjusted according to the electric field rotation angle. The electrode plate array adopts a multi-phase power supply method, and the rotation of the electric field direction is achieved by adjusting the phase relationship between each phase, making the electric field direction parallel to the fiber direction in the gap region, forming a rotating electric field, thus obtaining the adjusted electric field configuration parameters. Using the adjusted electric field configuration parameters, a rotating electric field is applied to the gap region with low energy storage, and the change in polarization intensity of the nano-frozen liquid in this region is monitored. When the polarization intensity reaches a preset threshold, the current electric field intensity is maintained, keeping the water molecules in the nano-frozen liquid in an ordered arrangement. Through this ordered water molecule structure, the temperature of the gap region is controlled to be below the freezing point but above the nucleation temperature, maintaining a supercooled liquid state, enabling the product to be stored cold without forming ice crystals.

[0045] Specifically, in one implementation, the deviation angle is calculated based on the geometric relationships in a three-dimensional vector space. Gap regions with low energy storage typically exhibit an irregular strip-like distribution, and the fiber arrangement direction within them is obtained by averaging the direction vectors of multiple fiber bundles to obtain the principal direction vector. The angle between the principal direction vector and the initial electric field direction vector is calculated using the vector dot product formula. When the angle exceeds 45 degrees, the energy transfer efficiency of the electric field in the fiber gaps decreases sharply. The determination of the electric field rotation angle takes into account the dielectric anisotropy of the nano-frozen liquid; the polarization efficiency reaches its peak when the electric field direction is parallel to the principal fiber direction.

[0046] Specifically, the electrode array employs a multi-phase power supply to achieve electric field rotation. In this embodiment, the system is configured as a six-phase rotating electric field, with each electrode plate connected to an independent AC power supply, and the phase difference between adjacent electrode plates is fixed at 60 degrees. This phase difference is calculated using the formula δ=360° / N, where δ is the phase difference and N is the number of electrode plates. The six electrode plates configuration achieves complete 360-degree rotational coverage. When it is necessary to rotate the electric field by a specific angle (e.g., 30 degrees), this is achieved by uniformly adding a corresponding phase offset to all power supplies. During the electric field rotation, the voltage amplitude of each electrode plate remains constant, only the phase relationship changes, thus forming a spatially rotating synthetic electric field. This rotating electric field generates periodically changing polarization directions in the nano-freezing liquid, allowing the interstices between fibers with different orientations to achieve sufficient polarization.

[0047] It should be noted that real-time monitoring of polarization intensity employs dielectric spectroscopy analysis. Miniature capacitive sensors are deployed in the interstitial region to measure changes in the local dielectric constant. When water molecules in the nano-frozen liquid form an ordered arrangement under the influence of an electric field, the dielectric constant increases significantly. Polarization intensity is positively correlated with the dielectric constant; by continuously measuring the time-series data of the dielectric constant, it is determined whether the polarization process has reached a steady state. The preset threshold is determined based on the composition of the nano-frozen liquid and the target freezing temperature, typically set to 1.5 to 2 times the initial dielectric constant. Once the monitored polarization intensity reaches the threshold and remains stable for more than a preset time, the current electric field strength and direction are maintained.

[0048] Preferably, the orderly arrangement of water molecules is maintained by continuously applying a constant electric field. Under the influence of the electric field, the dipole moments of water molecules align along the direction of the electric field, forming a quasi-lattice structure. The energy state of this ordered structure lies between the completely disordered liquid state and the crystalline state, and is in a metastable state. The metastable structure has a high potential energy, but due to the constraint of the electric field, water molecules cannot spontaneously rearrange to form ice crystals. The nanoparticles in the nano-freezing liquid further stabilize this ordered structure; the charges on the surface of the nanoparticles form electrostatic interactions with the water molecules, enhancing the stability of the water molecule arrangement.

[0049] For example, controlling the supercooling state involves two key factors: temperature and nucleation. The temperature in the interstitial region is controlled within the range of -5°C to -10°C by adjusting the operating parameters of the refrigeration system. This temperature is below the freezing point of water but above the homogeneous nucleation temperature. The homogeneous nucleation temperature is approximately -40°C; above this temperature, the probability of spontaneous nucleation of ice crystals is extremely low. Heterogeneous nucleation is the main mechanism for ice crystal formation during actual freezing, and its nucleation temperature depends on the nature of the nucleation sites. The nanoparticles in the nano-fast freezing liquid are surface-modified to be hydrophobic, which is unfavorable for ice crystal nucleation on their surface. At the same time, the ordered arrangement of water molecules under the influence of the electric field raises the nucleation energy barrier, reducing the heterogeneous nucleation temperature to below -10°C, further inhibiting ice crystal formation.

[0050] In one possible implementation, cold storage relies on the high specific heat capacity and delayed crystallization characteristics of a supercooled quick-freezing liquid. This quick-freezing liquid remains liquid below -10°C, with a specific heat capacity of approximately 3.5-4.0 kJ / kg·K. When food is immersed in it, heat transfer causes the temperature of the quick-freezing liquid to rise slowly and eventually undergo controlled crystallization. The crystallization process releases latent heat very slowly and produces very small ice crystals, thus avoiding damage to the food's cellular structure.

[0051] Understandably, seafood products contain a large amount of free and bound water within their fiber spaces. Free water easily forms large ice crystals, damaging cell membrane structures. By controlling the electric field to keep these water molecules in a supercooled state, both low-temperature preservation and ice crystal damage are achieved. This is especially important for high-value seafood products like tuna and salmon, where maintaining the integrity of muscle fibers directly impacts the product's commercial value.

[0052] For example, when processing beef tenderloin, the intermuscular gaps are approximately 10 to 20 micrometers wide, and these gaps are where ice crystals preferentially form. By precisely controlling the direction of the electric field to align with the fiber orientation, water molecules within the gaps are ordered along the fiber direction. This oriented water molecule structure is similar to a liquid crystal state, exhibiting fluidity while maintaining a certain degree of order. When thawing is required, removing the electric field causes the water molecules to quickly return to their disordered state, avoiding the juice loss problem that occurs in traditional freezing and thawing processes.

[0053] Step S105: Generate an electric field switching cycle based on the adjusted polarization intensity distribution, analyze the trend of the difference between the energy storage value inside the fiber and the energy storage value between the fiber gaps after the execution of the electric field switching cycle, evaluate the degree of energy storage balance inside and outside the fiber, and monitor whether the cold energy storage exceeds the preset range.

[0054] Based on the adjusted polarization intensity distribution data, the time required for the polarization intensity of different regions to reach stability is calculated. The maximum stability time for each region is taken as the basic cycle length. Multiple switching time points are set within the basic cycle to generate an electric field switching cycle that includes the switching time and duration. The electric field switching cycle is used to control the electrode plate array. At each switching time, the energy storage value inside the fiber and the energy storage value between the fibers are recorded. The difference between the two is calculated to form a difference sequence. The difference sequence is then averaged over time to obtain the trend of difference change. The energy storage equilibrium state is judged based on the trend of difference change. When the rate of change of the difference is less than a preset threshold, it is determined that the energy storage inside and outside the fiber has reached equilibrium. The ratio of the current energy storage value inside the fiber to the energy storage value between the fibers is calculated as the degree of energy storage equilibrium. Based on the degree of energy storage equilibrium, the total cold storage value is calculated by combining the energy storage value inside the fiber and the energy storage value between the fibers. When the total cold storage value exceeds the upper limit of the preset range, the electric field switching cycle length is extended by a preset ratio. When it is lower than the lower limit of the preset range, the electric field switching cycle length is shortened by a preset ratio. The cold storage is monitored to see if it exceeds the preset range.

[0055] Specifically, in one implementation, the generation of the electric field switching cycle is based on the spatiotemporal characteristics analysis of the polarization intensity distribution. The adjusted polarization intensity distribution data includes the polarization intensity values ​​of each region and the time parameters required to reach a steady state. Due to differences in fiber density and orientation, the polarization response time varies significantly among different regions. The polarization setup time in densely fibered regions is typically 100 to 200 milliseconds, while in sparsely fibered interstitial regions, it takes 300 to 500 milliseconds to reach stability. By statistically analyzing the stability time distribution of each region, the 95th percentile is selected as the base period length to ensure that most regions can complete the polarization process within one cycle.

[0056] Specifically, the timing of the electric field switching cycle is set in a non-uniform distribution. In the initial stage of polarization establishment, the switching frequency is high, with an electric field adjustment every 50 milliseconds to quickly bring each region close to the target polarization state. As the polarization process progresses, the switching interval gradually increases to 100 milliseconds, 200 milliseconds, until a steady state is reached. Each switching moment corresponds to specific electric field configuration parameters, including electric field strength, direction, and phase information. These parameters are dynamically determined based on the polarization state of each region at the current moment, forming a time-parameter mapping table, which is stored in the control system for real-time retrieval.

[0057] It should be noted that the recording of energy storage values ​​within and between fibers is achieved through a distributed sensor network. Based on existing IoT technology, non-invasive optical sensor arrays are deployed on the surface and near the surface of muscle tissue, while embedded micro-sensor nodes are uniformly arranged within the fiber gaps. Each sensor is responsible for monitoring changes in the dielectric constant of a local area. The sensors within the fibers primarily estimate the central region of the fiber bundle through surface scanning, while the gap sensors monitor the location of connective tissue between fiber bundles. The raw data collected by the sensors is converted into polarization intensity values ​​through a preprocessing circuit, and the energy storage value is calculated based on the linear relationship between polarization intensity and energy storage. The physical meaning of the energy storage value is the electric field energy stored per unit volume, measured in joules per cubic meter.

[0058] Preferably, the analysis of the difference change trend adopts the time cumulative averaging method. At each switching moment, the difference between the energy storage value inside the fiber and the energy storage value between the fibers is calculated, forming a discrete difference sequence. This sequence is cumulatively summed and divided by the cumulative time to obtain the average rate of change. When the average rate of change for several consecutive cycles is less than a preset threshold, the system is determined to have entered an energy storage equilibrium state. The preset threshold is determined based on the characteristics of the food material; for meat with a regular fiber structure, the threshold is set lower; for seafood with complex fiber arrangements, the threshold is appropriately increased. The degree of energy storage equilibrium is quantitatively characterized by a ratio. Ideally, the ratio of energy storage inside and outside the fiber is close to 1; in practical applications, fluctuations within the range of 0.8 to 1.2 are allowed.

[0059] For example, when processing large pieces of beef shank, due to the multi-layered helical structure of its fibers, there is a time difference in the response of different layers to an electric field. The surface fibers reach polarization stability first, while the deeper fibers require a longer time due to electric field decay. By setting a multi-stage switching cycle, a high-frequency switching electric field is first applied to the surface layer to rapidly polarize it. Then, the switching frequency is gradually reduced while the electric field strength is increased, so that the deeper fibers also reach the target polarization state. Throughout the process, the energy storage difference between each layer is continuously monitored. When the energy storage difference of all layers converges to an allowable range, the system enters a stable operating mode.

[0060] In one possible implementation, the calculation of total cold storage value comprehensively considers the energy storage contributions from both the fiber interior and interstitial regions. Total cold storage equals the energy storage value within the fiber multiplied by the fiber volume, plus the energy storage value between the fibers multiplied by the interstitial volume. Because the nano-frozen liquid in its supercooled state has a high specific heat capacity, its stored cold storage capacity far exceeds that of ice at the same temperature. The upper limit of the preset range is determined based on the heat capacity of the food to avoid overcooling and nutrient loss; the lower limit is set according to preservation requirements to ensure effective inhibition of microbial activity.

[0061] Understandably, the dynamic adjustment of the electric field strength employs a proportional control strategy. When the total cold storage exceeds the upper limit, the control system reduces the electric field strength according to the ratio of the excess to the upper limit. The reduction is typically 10% to 30% of the current strength to avoid drastic changes that could cause polarization instability. Conversely, when the storage value is below the lower limit, the electric field strength is increased proportionally, with the increase controlled within 20%. During the adjustment process, the electric field direction remains unchanged; only the intensity is altered, simplifying the control logic and improving system stability.

[0062] For example, in the application of quick-frozen shrimp, due to the fine fibers and high moisture content of shrimp meat, localized overcooling is prone to occur. Real-time monitoring revealed that the cold storage value in the head region of the shrimp reached its upper limit first, while the tail region had not yet reached its lower limit. The system automatically adjusted the configuration of the electrode plate array, reducing the electric field intensity in the head region while maintaining or slightly increasing the electric field intensity in the tail region, achieving a uniform distribution of cold energy overall and avoiding the common problem of over-freezing in the head and under-freezing in the tail region in traditional quick-freezing.

[0063] Step S106: When the energy storage inside and outside the fiber is balanced and the cold storage exceeds the preset range, the food crystallizes instantly. After the polarization intensity distribution is adjusted, the polarization intensity gradient direction of each region is extracted. Based on the spatial correspondence between the polarization intensity gradient direction and the fiber arrangement angle, the orientation angle of ice crystal growth is identified.

[0064] The system monitors the energy storage equilibrium state and cold storage value inside and outside the fiber. When the energy storage ratio is within a preset range and the cold storage exceeds a preset threshold, the electric field is removed to cause instantaneous crystallization of the food. The polarization intensity value and spatial coordinates of each region at the moment of crystallization are recorded. Based on the polarization intensity value and spatial coordinates, the ratio of the polarization intensity difference to the distance between adjacent measurement points is calculated to obtain the magnitude of the polarization intensity gradient at each point. The gradient direction vector is determined by the components of the gradient on the three-dimensional coordinate axis. The angle between the gradient direction vector and the fiber arrangement direction at the corresponding position is obtained. When the angle is less than a preset threshold, it is determined that the ice crystal grows along the fiber axis; when the angle is greater than the preset threshold, it is determined that the ice crystal grows perpendicular to the fiber. Based on the angle determination results and the three-dimensional spatial arrangement data of the fiber, the orientation angle of ice crystal growth in each region is identified.

[0065] Specifically, in this embodiment, the triggering of instantaneous crystallization is based on a dual-condition judgment mechanism. The energy storage equilibrium state is determined by the ratio of the energy storage value within the fiber to the energy storage value between the fibers. When this ratio remains stable within the range of 0.9 to 1.1 for a preset time, equilibrium is considered achieved. The determination of cold storage is based on the total energy storage value, which is equal to the sum of the products of the energy storage value of each region and its volume. When the total energy storage value exceeds a threshold determined according to the heat capacity of the food material, the cold storage condition is met. When both conditions are met simultaneously, the control system immediately removes the applied electric field, causing the supercooled water in the nano-freezing liquid to instantly lose its electric field constraint, triggering a uniform nucleation process.

[0066] Specifically, an electric field is applied to induce water molecule polarization, and the polarization intensity values ​​of each region are recorded before removal. These data reflect the stored electric field energy density and their location within the three-dimensional fiber network. Regions with high polarization intensity have lower energy states and preferentially form ice crystals during subsequent cooling-induced nucleation. These data can be used to predict the initial nucleation distribution and provide a basis for gradient calculations.

[0067] It should be noted that the central difference method is used to improve the accuracy of the polarization intensity gradient calculation. For any point in space, the difference in polarization intensity between it and its neighboring points in the x, y, and z directions is calculated, and then divided by the corresponding spatial distance to obtain the gradient components in the three directions. The gradient magnitude is equal to the square root of the sum of the squares of the three components, reflecting the spatial rate of change of polarization intensity. The gradient direction vector is determined by the ratio of the three components and points in the direction of the fastest increase in polarization intensity. In densely fibrous regions, the polarization intensity gradient is small due to the shielding effect of the fibers; while at the boundaries of the interfiber gaps, the polarization intensity changes sharply, and the gradient value increases significantly. This gradient distribution characteristic directly affects the ice crystal growth pattern.

[0068] Preferably, the angle between the gradient direction and the fiber alignment direction is obtained through vector operations. The fiber alignment direction is extracted from the aforementioned three-dimensional spatial arrangement data, with each position corresponding to a fiber direction vector. The cosine of the angle between the gradient direction vector and the fiber direction vector is equal to the inner product of the two vectors divided by the product of their magnitudes. When the angle is less than 30 degrees, the gradient direction is basically parallel to the fiber, and ice crystals tend to grow along the fiber axis, forming needle-like or columnar ice crystals. In this growth mode, the ice crystals extend along the natural channels between fibers, causing less damage to the fiber structure. When the angle is greater than 60 degrees, the gradient direction is nearly perpendicular to the fiber, and the ice crystals grow laterally through the fiber bundle, easily causing fiber breakage.

[0069] For example, when processing sea bass fillets, the muscle fibers exhibit a typical parallel arrangement with a highly consistent fiber orientation. By precisely controlling the polarization intensity distribution before the electric field is removed, the gradient direction is kept at a small angle to the fiber direction. Experimental observations revealed that when the angle is controlled within 15 degrees, the formed ice crystals mainly grow along the fiber direction, exhibiting a slender needle-like structure, typically less than 5 micrometers in diameter and over 100 micrometers in length. These directionally growing ice crystals do not puncture cell membranes, resulting in a reduction of over 80% in juice loss after thawing.

[0070] In one possible implementation, identifying the ice crystal growth orientation angle requires comprehensive consideration of multiple factors. Besides the gradient direction and the fiber angle, these include the local temperature gradient, nanoparticle density, and residual electric field strength. The temperature gradient determines the thermodynamic driving force direction of ice crystal growth, nanoparticles, acting as heterogeneous nucleation centers, influence the initial orientation of the ice crystals, and the residual electric field guides the continued growth of the ice crystals. By establishing a multi-parameter comprehensive evaluation method, assigning corresponding weight coefficients to each influencing factor, and performing weighted calculations, the final ice crystal growth orientation angle is obtained.

[0071] Understandably, the spatial distribution of orientation angles exhibits a non-uniform characteristic. Within the fiber bundles, due to the constraint of the fibers, the variation range of ice crystal growth angles is relatively small, mainly concentrated in the direction parallel to the fibers. However, at the junctions of fiber bundles, the influence of fibers from different directions is superimposed, resulting in a diverse range of ice crystal growth angles. By plotting the orientation angle distribution, the spatial characteristics of ice crystal growth throughout the sample can be visually displayed, providing a basis for evaluating the freezing effect.

[0072] For example, when processing beef, due to its rich marbling and alternating distribution of fat and lean meat, the growth angle of ice crystals varies significantly across different areas. In fat areas, where there is a lack of fibrous structure, ice crystals grow radially; in lean meat areas, ice crystals grow directionally along the fibers; and at the interface between fat and lean meat, the growth direction of ice crystals is intermediate, exhibiting a transitional characteristic.

[0073] Step S107: Match the orientation angle of ice crystal growth with the preset ice crystal growth direction requirement, identify the deviation of ice crystal growth angle, adjust the electric field switching cycle according to the deviation of ice crystal growth angle, determine the uniform polarization intensity of the nano-freezing liquid in the fiber gap, and control the ice crystal to grow in the direction of fiber gap at the preset freezing temperature for freezing preservation, so as to achieve the freshness locking effect.

[0074] The directional angle data of ice crystal growth is acquired and compared point-by-point with the preset growth direction along the fiber gap. The angle difference is calculated as the deviation value. If the deviation value exceeds a preset threshold, it is marked as a deviation point. The spatial distribution of deviation points is statistically analyzed to obtain an angle deviation distribution map. The location of the deviation region is extracted based on the angle deviation distribution map, and the electric field switching cycle parameter corresponding to the region is analyzed. The polarization establishment rate of the region is changed by adjusting the switching time interval, and the polarization intensity gradient direction is corrected to generate an adjusted electric field switching cycle. The electric field is reapplied using the adjusted electric field switching cycle, and the polarization intensity value at each point in the fiber gap is monitored. The ratio of the standard deviation to the average value of the polarization intensity is calculated. When the ratio is less than a preset threshold, uniform polarization intensity is determined to be achieved. The uniform polarization intensity is maintained, and the cooling rate is controlled at a preset freezing temperature to allow ice crystals to preferentially nucleate in the fiber gap and grow along the gap direction. By controlling the nucleation density and growth rate, directional cryopreservation is completed to achieve a freshness-locking effect.

[0075] Specifically, in one implementation, the predetermined growth direction is determined based on the spatial geometric characteristics of the fiber gaps. The fiber gaps exhibit a network distribution in three-dimensional space, and their main channel direction is obtained by extracting the gap space through a skeletonization process. The skeletonization algorithm employs a central axis transformation method to voxelize the three-dimensional gap space, extracting the central axis as the ideal ice crystal growth path through an iterative refinement process. Subsequently, the major axis direction of the main channel is extracted from the central axis as the ideal growth direction, avoiding lateral penetration of the fiber bundle. The angular deviation is calculated using the vector angle method, performing an inner product operation between the actually measured ice crystal growth direction vector and the ideal direction vector to obtain the cosine value of the angle, and then calculating the deviation angle using the inverse cosine function.

[0076] Specifically, generating the angular deviation distribution map requires dividing the entire sample space into a grid. Each grid cell is approximately 100 micrometers cubic, roughly the diameter of a typical muscle fiber. Angle deviation values ​​are calculated at the center point of each grid cell, and points with deviations exceeding 15 degrees are marked as areas requiring adjustment. These deviation points are often concentrated at fiber bundle intersections, the fat-lean meat interface, and sample edge areas. The deviation distribution map is then presented using 3D visualization technology, with areas of large deviations represented by warm colors and areas of small deviations by cool colors, forming an intuitive spatial distribution image.

[0077] It should be noted that this system employs an electrode plate array hardware structure, consisting of multiple independent electrode plates, each corresponding to a specific spatial region. Independent control of each region is achieved through an embedded controller, including individual settings for voltage, frequency, and phase. The adjustment mechanism for the electric field switching cycle is based on polarization relaxation time theory. When a large angular deviation is detected in a certain region, the current electric field switching parameters for that region are analyzed, particularly the switching frequency and duration. If the deviation is due to insufficient polarization establishment, the electric field application time in that region is extended, allowing sufficient time for water molecules to complete their orientation. The specific adjustment amount is determined based on the magnitude of the deviation angle; for every 10-degree increase in deviation, the electric field application time is extended by 20%. Conversely, if the deviation is caused by excessive polarization, the application time is shortened. The adjusted switching cycle exhibits a non-uniform distribution, with customized switching parameters for different regions, achieving precise polarization control. This differentiated control requires the electrode plate array to have independent control capabilities for each region, with each electrode plate corresponding to a specific spatial region and its voltage, frequency, and phase parameters set independently.

[0078] Preferably, the coefficient of variation (COP) is used as a quantitative indicator to evaluate uniform polarization intensity. The COP equals the standard deviation divided by the mean, and its dimensionless nature makes it suitable for comparing different intensity levels. Polarization intensity data is acquired in real time within the aforementioned embedded micro-sensor network, with the COP updated every second. When the COP drops below 0.1, uniform polarization is considered achieved. This threshold takes into account measurement errors and the inherent inhomogeneity of the material. Achieving uniform polarization intensity depends not only on optimizing the electric field parameters but also on considering the flowability of the nano-freezing liquid. Through weak circulating flow, nanoparticles are uniformly distributed within the gaps, avoiding excessively high or low local concentrations that could negatively impact the polarization effect.

[0079] In one possible implementation, the selection of the preset freezing temperature needs to balance the freezing rate and the ice crystal control effect. The temperature is set in the range of -18°C to -25°C, a range that provides sufficient freezing driving force without causing a large number of nucleation crystals instantaneously. The cooling rate is controlled at 2 to 3 degrees Celsius per minute to make the ice crystal nucleation and growth process controllable. Nucleation preferentially occurs at preset nucleation sites in the interfibrillary spaces, and these nucleation sites are formed through the prior regulation of polarization intensity distribution.

[0080] Understandably, the directional growth of ice crystals along the interstitial space depends on the synergistic effect of temperature and concentration gradients. During freezing, the interior of the fiber cools more slowly due to its larger heat capacity, while the nano-speed-freezing liquid in the interstitial space cools more rapidly, creating a temperature gradient from the fiber to the interstitial space. This temperature gradient drives water to migrate from the fiber interior to the interstitial space, forming ice crystals within it. Simultaneously, the ice crystal formation process displaces solutes, creating a high-concentration region at the ice crystal front, generating an osmotic pressure gradient that further promotes the directional migration of water. By precisely controlling the direction and magnitude of these two gradients, the directional growth of ice crystals can be achieved.

[0081] For example, when processing lobster tail meat, its unique circular muscle fiber arrangement requires ice crystals to grow along the inter-ring gaps. By setting up a circular electrode array, an electric field distribution matching the fiber arrangement is generated. During freezing, the ice crystals advance layer by layer from the outer ring to the inner ring, forming a concentric circle distribution. After thawing, the lobster meat retains its original elasticity and transparency, with a juice loss rate of less than 2%, achieving excellent freshness preservation.

[0082] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields, characterized in that, The method includes: The three-dimensional spatial arrangement of muscle fibers in nano-freezing fluid was obtained, the fiber arrangement angle and fiber coverage density of muscle fibers were identified, the preliminary electric field direction of the superimposed spatial electric field and the polarization intensity of each region were collected, and the average polarization intensity was obtained. The unidirectional electric field coverage is determined based on the fiber arrangement angle, and the polarization intensity of fibers with different orientations is determined based on the unidirectional electric field coverage and fiber coverage density. By comparing the polarization intensity of fibers with different orientations with the mean polarization intensity, regions with polarization intensity lower than the mean are identified as gap regions with low energy storage. The energy storage difference value of the gap regions with low energy storage is extracted, and the energy storage value inside the fiber and the energy storage value between the fibers are identified. The electric field rotation angle is identified by the deviation angle between the gap region with low energy storage and the initial electric field direction. The polarization intensity distribution of the gap region with low energy storage is adjusted according to the electric field rotation angle. The supercooling characteristics of the nano-freezing liquid are used to store cold energy without forming ice crystals. The electric field switching cycle is generated based on the adjusted polarization intensity distribution. The trend of the difference between the energy storage value inside the fiber and the energy storage value between the fiber gaps after the execution of the electric field switching cycle is analyzed to evaluate the degree of energy storage balance inside and outside the fiber and monitor the cold energy storage. When the energy storage inside and outside the fiber is balanced and the cold storage exceeds the range, the food crystallizes instantly. After the polarization intensity distribution is adjusted, the polarization intensity gradient direction of each region is extracted. Based on the spatial correspondence between the polarization intensity gradient direction and the fiber arrangement angle, the orientation angle of ice crystal growth is identified. Matching the orientation angle of ice crystal growth with the required direction of ice crystal growth, identifying the deviation of the ice crystal growth angle, adjusting the electric field switching cycle according to the deviation of the ice crystal growth angle, determining the uniform polarization intensity of the nano-freezing liquid in the fiber gap, and controlling the directional growth of ice crystals along the fiber gap direction for cryopreservation at freezing temperature.

2. The nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields according to claim 1, characterized in that, The process of obtaining the three-dimensional spatial arrangement of muscle fibers in the nano-freezing liquid, identifying the fiber arrangement angle and fiber coverage density, acquiring the preliminary electric field direction of the superimposed spatial electric field and the polarization intensity of each region, and obtaining the average polarization intensity includes: An ultrasonic scanner was used to scan muscle tissue immersed in a nano-freezing liquid layer by layer to obtain cross-sectional image data. The fiber contour coordinates in the cross-sectional image were extracted by an image recognition algorithm. The three-dimensional spatial trajectory of the fiber bundle was constructed according to the spatial connection relationship of the corresponding fiber contour coordinates between adjacent layers to obtain the three-dimensional spatial arrangement of muscle fibers. For the three-dimensional spatial arrangement of muscle fibers, the angle between the central axes of adjacent fiber bundles was calculated, the number of fiber bundles in each fiber group per unit volume was counted, and the fiber coverage density was calculated. An array of electrode plates is arranged in the quick-freezing device according to the fiber coverage density. A uniform electric field is applied as the initial electric field direction. A Hall effect sensor probe is used to measure the local electric field intensity value in different fiber group regions, and the polarization intensity data of each measurement point is recorded. The weighted average value of all measurement points is calculated using the polarization intensity data to obtain the average polarization intensity.

3. The nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields according to claim 1, characterized in that, The determination of unidirectional electric field coverage based on fiber arrangement angle, and the determination of polarization intensity of fibers with different orientations based on unidirectional electric field coverage and fiber coverage density, include: Obtain the direction of the principal axis of each fiber bundle in the three-dimensional spatial arrangement of muscle fibers, calculate the angle between the principal axis of the fiber bundle and the direction of the initial unidirectional electric field, and calculate the ratio of the number of fibers that can be covered to the total number of fibers to determine the coverage rate of the unidirectional electric field. Based on the unidirectional electric field coverage rate, fiber coverage density data of uncovered fiber areas are extracted, and polarization intensity adjustment coefficients for different areas are obtained through function mapping. The initial polarization intensity value of each region is corrected by the polarization intensity adjustment coefficient, and the polarization intensity value of each oriented fiber under the current electric field is calculated by combining the dielectric constant of different oriented fiber groups, thereby determining the polarization intensity of different oriented fibers.

4. The nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields according to claim 1, characterized in that, The step of comparing the polarization intensity of fibers with different orientations with the average polarization intensity to identify regions with polarization intensity lower than the average, and determining these regions as gap regions with low energy storage, includes: The polarization intensity data of fibers with different orientations are obtained and compared point by point with the average polarization intensity. The region is marked as a low polarization region. Based on the positional relationship between the low polarization region and the spatial arrangement of the fibers, the low polarization region located between the fiber bundles is determined to be a gap region with low energy storage.

5. The nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields according to claim 1, characterized in that, The method of identifying the electric field rotation angle by the deviation angle between the gap region with low energy storage and the initial electric field direction includes: Based on the spatial distribution of the gap region with low energy storage, the three-dimensional spatial arrangement of muscle fibers is obtained. For the three-dimensional spatial arrangement of muscle fibers, the main direction vector of fiber arrangement in the gap region is extracted. The angle between the main direction vector and the initial electric field direction vector is calculated as the deviation angle. The electric field rotation angle is determined based on the deviation angle.

6. The nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields according to claim 1, characterized in that, The electric field switching cycle is generated based on the adjusted polarization intensity distribution. The trend of the difference between the energy storage value inside and outside the fiber and the energy storage value between the fiber gaps after the electric field switching cycle is executed is analyzed to assess the degree of energy storage balance inside and outside the fiber and to monitor cold energy storage, including: Based on the adjusted polarization intensity distribution data, the time required for the polarization intensity in different regions to reach stability is calculated. The maximum value of the stability time in each region is taken as the basic period length. Multiple switching time points are set within the basic period to generate an electric field switching period that includes the switching time and duration. The electric field switching cycle control electrode plate array is used to record the energy storage value inside the fiber and the energy storage value between the fibers at each switching moment. The difference between the two is calculated to form a difference sequence. The difference sequence is then accumulated and averaged over time to obtain the trend of difference change. The ratio of the current energy storage value within the fiber to the energy storage value between the fiber gaps is calculated based on the trend of the difference change as the degree of energy storage balance. The total cold storage value is calculated by combining the energy storage balance with the energy storage value within the fiber and the energy storage value between the fibers.

7. The nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields according to claim 1, characterized in that, When the energy storage inside and outside the fiber is balanced and the cold storage exceeds the range, the food crystallizes instantly. After adjusting the polarization intensity distribution, the polarization intensity gradient direction of each region is extracted. Based on the spatial correspondence between the polarization intensity gradient direction and the fiber arrangement angle, the orientation angle of ice crystal growth is identified, including: Monitor the energy storage equilibrium state and cold storage value inside and outside the fiber, remove the electric field to make the food crystallize instantly, and record the polarization intensity value and spatial coordinates of each region at the moment of crystallization triggering. Based on the polarization intensity value and spatial coordinates, the polarization intensity difference and distance ratio between adjacent measurement points are calculated to obtain the polarization intensity gradient magnitude at each point. The gradient direction vector is determined by the components of the gradient on the three-dimensional coordinate axes. Obtain the angle between the gradient direction vector and the fiber arrangement direction at the corresponding position; identify the orientation angle of ice crystal growth in each region by using the angle between the gradient direction vector and the fiber arrangement direction at the corresponding position and the three-dimensional spatial arrangement data of the fibers.

8. The nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields according to claim 1, characterized in that, The process of matching the orientation angle of ice crystal growth with the required direction of ice crystal growth, identifying deviations in the ice crystal growth angle, adjusting the electric field switching cycle based on the deviations, determining the uniform polarization intensity of the nano-freezing liquid in the fiber gaps, and controlling the directional growth of ice crystals along the fiber gaps at freezing temperatures for cryopreservation includes: Obtain the orientation angle data of ice crystal growth, compare it point by point with the growth direction along the fiber gap, calculate the angle difference as the deviation value, and statistically analyze the spatial distribution of the deviation points to obtain the angle deviation distribution map. Based on the angle deviation distribution map, the location of the deviation region is extracted, the electric field switching cycle parameter corresponding to the region is analyzed, the polarization establishment rate of the region is changed by adjusting the switching time interval, the polarization intensity gradient direction is corrected, and the adjusted electric field switching cycle is generated. The electric field is reapplied using the adjusted electric field switching cycle, and the polarization intensity value at each point in the fiber gap is monitored. The ratio of the standard deviation to the average value of the polarization intensity is calculated.

9. The nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields according to claim 4, characterized in that, The step of extracting the energy storage difference value of the gap region with low energy storage and identifying the energy storage value within the fiber and the energy storage value between the fiber gaps includes: For the gap region with low energy storage, calculate the difference between the polarization intensity at each point in the gap region and the mean polarization intensity, and take the absolute value of the difference as the energy storage difference value. By using the distribution map of the interstitial region, the gradient change detection method is used to identify the abrupt boundary of polarization intensity. The high polarization intensity region inside the boundary is determined to be the fiber interior, and the low polarization intensity region outside the boundary is determined to be the fiber interstitial region. The average value of polarization intensity at the measurement points inside the fiber and the fiber interstitial region is calculated respectively.

10. The nano-fast freezing and freshness-preserving method based on superimposed spatial electric fields as described in claim 5, characterized in that, The method of adjusting the polarization intensity distribution in the gap region with low energy storage according to the electric field rotation angle, and utilizing the supercooling characteristics of the nano-freezing liquid for cold storage without forming ice crystals, includes: The phase difference of each electrode in the electrode plate array is adjusted according to the electric field rotation angle. The electrode plate array adopts a multi-phase power supply method. The rotation of the electric field direction is achieved by adjusting the phase relationship between each phase, so that the electric field direction is parallel to the fiber direction in the gap region, forming a rotating electric field, and the adjusted electric field configuration parameters are obtained. Using the adjusted electric field configuration parameters, a rotating electric field is applied to the gap region where the energy storage is low. The change in polarization intensity of the nano-frozen liquid in the gap region is monitored to keep the water molecules in the nano-frozen liquid in an orderly arrangement. Through the orderly arrangement of water molecules, the temperature of the gap region is controlled to be lower than the freezing point but higher than the nucleation temperature, thus maintaining the supercooled liquid state.

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