A method for preparing carrot seed pellets based on single seed nucleation and wet screening control

Abstract

This invention relates to the field of seed processing technology. The invention discloses a method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control, comprising the following steps: (1) Preparation of wet carrot seed pellets: using the same batch of naked carrot seeds as raw materials; (2) Sieving of wet carrot seed pellets: during pelleting, the pelleted seeds are sieved using a standard grain sieve to obtain sieved wet carrot seed pellets; (3) Microwave hot air pretreatment; (4) Hot air drying; (5) Tempering the pre-dried carrot seed pellets to obtain carrot seed pellets. This invention also provides a carrot seed pellet and its application. The carrot seed pellets prepared by the method of this invention have a concentrated particle size, high particle size uniformity, high seed content, and high single-seed rate. They can also lyse and release seeds after absorbing water, making them suitable for pretreatment before mechanized precision sowing of carrot seeds.

Description

Technical Field

[0001] This invention relates to the field of seed processing technology, and in particular to a method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control. Background Technology

[0002] carrot( Daucus carota Carrots are an important vegetable crop widely cultivated globally. However, carrot seeds are small and irregularly shaped, making them prone to uneven sowing, missed sowing, and double sowing when directly used in mechanized precision seeding. Pelletizing can transform carrot seeds into larger, more uniformly shaped pellets, thereby improving their flowability and adaptability to mechanized sowing.

[0003] Current carrot seed pelleting processes typically utilize seed pelleting machines, employing moisture or binders to adhere pelleting powder layer by layer to the seed surface. However, carrot seeds are small in size, irregular in shape, and exhibit significant individual differences. During pelleting, problems easily arise such as powder detaching from the seed and agglomerating to form empty pellets, multiple seeds sticking together to form multi-seed pellets, wet pellets sticking together, excessively wide particle size distribution, and discontinuous surface coating. These problems lead to a decrease in the seed yield, single-seed rate, particle size uniformity, and sowing adaptability of carrot seed pellets.

[0004] Furthermore, the formed wet carrot seed pellets still require subsequent drying. If the particle size distribution of the wet pellets is not concentrated, or if there are empty pellets, multi-seed pellets, sticky pellets, or deformed pellets, the quality stability during subsequent drying, packaging, storage, and sowing processes will also be affected. Therefore, there is an urgent need for a method that can stably achieve the goal of using a single carrot seed as the nucleation center and obtain carrot seed pellets with a uniform particle size through wet sieving. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control, which solves the problems that easily occur in the existing carrot seed pelleting process, such as empty pellets, multiple pellets, sticky pellets, deformed pellets, and uneven particle size distribution.

[0006] To address the above problems, the present invention provides the following technical solution: A method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control includes the following steps: (1) Preparation of wet carrot seed pellets Using the same batch of naked carrot seeds as raw materials, damaged seeds, shriveled seeds and impurities are removed to obtain carrot seeds to be pelletized; the carrot seeds are poured into a seed pelleting machine, the seed pelleting machine is started, carrot seed powder is slowly added, and water is added at the same time; (2) Screening of wet carrot seed pellets During the pelleting process, a standard grain sieve is used to sieve the pelleted seeds to obtain wet carrot seed pellets after sieving. (3) Microwave hot air pretreatment The sieved wet carrot seed pellets are placed in a drying device and kept in a rolling state during the drying process for microwave hot air pretreatment. (4) Hot air drying After the microwave hot air pretreatment is completed, the microwave treatment is stopped, and the hot air treatment is carried out to obtain pre-dried carrot seed pellets. (5) Resuscitation treatment The carrot seed pellets are obtained by slow tempering after pre-drying.

[0007] In the method for preparing carrot seed pellets based on single seed nucleation and wet sieving control as described above, in step (1), the mass ratio of carrot seeds, carrot seed powder and water is 1:(30-35):(6-8).

[0008] In the method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control as described above, in step (1), the mass ratio of carrot seeds, carrot seed powder and water is 1:33.5:7.

[0009] In the carrot seed pellet preparation method based on single seed nucleation and wet sieving control as described above, in step (1), the powder feeding speed of the seed pellet machine is 200-300 r / min.

[0010] As described above, in the method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control, water is added in step (1) by spraying. Water is added by spraying to uniformly moisten the surface of the carrot seeds; pelleting powder is added in small amounts multiple times to allow the pelleting powder to preferentially adhere to the surface of the single carrot seed; thus forming initial wet pellets with the single carrot seed as the core.

[0011] As described above, in the method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control, in step (2), the standard sieve is a 3.5 mm and a 4.0 mm standard sieve, and wet carrot seed pellets with a particle size of 3.5 to 4.0 mm are obtained by sieving.

[0012] As described above, in the method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control, in steps (3) and (4), an infrared thermal imager is used to collect the surface temperature distribution of the carrot seed pellet material layer, and the area where the carrot seed pellet material layer is located in the infrared thermal image is used as the overall analysis area to calculate the temperature uniformity coefficient and temperature variation coefficient to evaluate the heating uniformity of the pellets.

[0013] The technical principle of this invention lies in the fact that carrot seeds are small in size and irregular in shape, making them prone to problems such as powder agglomeration, multiple seeds sticking together, and wet pellets sticking together during pelleting. This invention addresses these issues by adding water via spraying, creating a uniformly moistened surface on each individual carrot seed. By adding pelleting powder in small, multiple batches, the powder preferentially adheres to the surface of each individual carrot seed, forming an initial wet pellet with the seed as its core, thereby improving the stability of single-seed nucleation. During pellet enlargement, by controlling the mass ratio of carrot seeds, pelleting powder, and water, as well as the powder feeding speed of the seed pelleting machine, the powder deposition rate, moisture wetting degree, and pellet growth rate are matched, reducing the formation of empty pellets, multi-seed pellets, and sticky pellets. Furthermore, after the wet pellets approach the target particle size, they are rounded and shaped, and then wet-screened using 3.5 mm and 4.0 mm standard sieves to remove excessively small, large, clumped, and deformed particles. This results in carrot seed pellets with concentrated particle size, high seed content, high single-seed rate, and the ability to lyse when soaked in water. Compared with existing technologies, this invention combines single-seed nucleation control and wet-screening control, ensuring that carrot seeds remain stable as independent nucleation centers during pelleting, preventing the pelleted powder from detaching from the seeds and forming individual clumps, thus reducing the empty pellet rate. It also reduces the likelihood of multiple seeds sticking together under excessively wet conditions, forming multiple pellets. Through wet-screening, this invention can remove wet pellets with unqualified particle size and abnormal shape before drying, ensuring that the carrot seed pellets entering the subsequent drying, packaging, and sowing stages have better particle size consistency and forming stability, which is beneficial for improving the adaptability of carrot seed pellets for mechanized precision sowing.

[0014] Based on the same inventive concept, this invention provides a carrot seed pellet, which is prepared by the carrot seed pellet preparation method based on single seed nucleation and wet sieving control as described above.

[0015] The carrot seed pellets described above are characterized in that the particle size uniformity of the carrot seed pellets is not less than 95%, the seed content is not less than 90%, and the single seed content is not less than 90%.

[0016] Based on the same inventive concept, this invention provides carrot seed pellets prepared by the preparation method described above, or the application of carrot seed pellets prepared by the method described above in mechanized precision seeding.

[0017] Compared with existing technologies, the beneficial effects and advantages of this invention are: 1. This invention uses spray water and adds pelleting powder in small amounts multiple times to make the pelleting powder adhere preferentially to the surface of a single carrot seed, reducing the situation where the powder agglomerates to form empty pellets and multiple seeds stick together to form multiple pellets, thus obtaining carrot seed pellets with concentrated particle size, high seed content, high single seed rate, and the ability to be soaked and lysed.

[0018] 2. This invention improves the stability of single-seed nucleation by controlling the mass ratio of carrot seeds, pelleting powder, and water, as well as the powder feeding speed of the seed pelleting machine, so that the powder addition speed, the degree of water wetting, and the pellet growth rate are matched.

[0019] 3. This invention uses a rounding and shaping process to further round and compact the surface of wet carrot seed pellets and form a continuous coating layer, reducing the risk of surface defects and powdering during subsequent screening, transfer, drying and sowing processes.

[0020] 4. This invention uses 3.5mm and 4.0mm standard sieves for wet sieving to remove excessively small, excessively large, empty, multi-seed, sticky, and deformed particles, so that the wet carrot seed pellets entering the subsequent processing stage have a concentrated particle size and more uniform shape.

[0021] 5. The carrot seed pellets prepared by this invention have high particle size uniformity, seed content and single seed rate, and can break down and release the internal seeds after soaking in water, making them suitable for pretreatment before mechanized precision sowing of carrot seeds. Attached Figure Description

[0022] Figure 1 This is a photograph of the naked-species carrot of the present invention; Figure 2 This is a comparative observation of the formation state of carrot seed pellets under different moisture addition conditions. Figure 2 A is comparative example 2. Figure 2 B is comparative example 3.

[0023] Figure 3 This is a photograph of carrot seed pellets with a particle size of 3.5–4.0 mm obtained by sieving in Example 3 of the present invention. Figure 4 This is an observation chart of the seed content and single seed rate of carrot seed pellets in Example 3 of the present invention; Figure 5 This is an observation diagram of the lysis of carrot seed pellets after soaking in water, as shown in Example 3 of the present invention. Figure 6 This is a graph showing the change in moisture ratio with drying time during different drying processes.

[0024] Figure 7 Figures illustrating the germination phenomenon of pellets after different drying treatments; Figure 8 Infrared thermal imaging temperature distribution of carrot seed pellets before, during and after drying under different drying methods; Figure 9 Scanning electron microscope images of naked carrot seeds and carrot seed pellets after microwave hot air drying. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0027] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0028] Unless otherwise specified, the materials and reagents used in the following examples are all available from conventional commercial sources.

[0029] This embodiment uses carrot seeds of the variety "Gengenhong," purchased from Shandong Shouguang Xinxinran Horticulture Co., Ltd. The carrot pelleting powder used is Bellerophon 1200-mesh slow-release pelleting material; alternatively, carrot seed pelleting powder provided by Qingdao Runhua Agricultural Technology Co., Ltd., or other commercially available vegetable seed pelleting powders that meet the above performance requirements, can also be used. The specific product name, manufacturer, and batch number of the pelleting powder do not constitute a limitation on the scope of protection of this invention. The pelleting was performed using an RH-325 seed pelleting machine from Shandong Qingdao Runhua Agricultural Technology Co., Ltd.

[0030] The drying device includes a drying chamber, a microwave generating unit, a hot air supply unit, a rolling bed support unit, a dehumidification unit, and a control unit. The rolling bed support unit carries the wet carrot seed pellets and rotates them during the drying process. The microwave generating unit applies microwave energy into the drying chamber. The hot air supply unit introduces hot air at a set temperature and speed into the drying chamber. The dehumidification unit removes the hot and humid air generated during the drying process from the drying chamber. The control unit controls the operation of the microwave generating unit, the hot air supply unit, the rolling bed support unit, and the dehumidification unit. For example, a microwave infrared hot air rolling drying device as described in Chinese Patent CN 202210436856.8 can be used.

[0031] Example 1: A method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control includes the following steps: (1) Preparation of wet carrot seed pellets In this embodiment, the same batch of naked carrot seeds was used as raw material. Damaged seeds, shriveled seeds, and impurities were removed to obtain carrot seeds to be pelletized. The physical state of the naked carrot seeds is as follows: Figure 1 As shown. Naked carrot seeds have a small particle size, irregular shape, and grooved surface, which easily leads to uneven sowing, missed sowing, and double sowing when directly used for mechanized precision seeding. Therefore, pelleting is performed. Take 100g of carrot seeds and pour them into the coating pan of the RH-325 seed pelleting machine, and weigh out 3350g of carrot seed powder. Start the seed pelleting machine, adjust the powder feeding speed to 200r / min, slowly add the carrot seed powder, and simultaneously add water to the coating pan using a spray method. The mass ratio of carrot seeds, carrot seed powder, and water is 1:33.5:7, resulting in wet carrot seed pellets. (2) Screening of wet carrot seed pellets During the pelleting process, the pelleted seeds were sieved using 3.5mm and 4.0mm standard grain sieves. When the pelleted seed particle size reached the range of 3.5–4.0mm, the pelleting operation was stopped, and wet carrot seed pellets with a particle size of 3.5–4.0mm were obtained by sieving. (3) Microwave hot air pretreatment The sieved wet carrot seed pellets are placed in a drying device and kept in a rolling state during the drying process; hot air at 38°C and 3 m / s is introduced into the wet carrot seed pellets, and microwave power density of 1.5 W / g is applied at the same time, with a pretreatment time of 2 min and a rolling bed speed of 1 r / min. (4) Hot air drying After the microwave hot air pretreatment is completed, the microwave treatment is stopped, but the hot air supply unit and the rolling bed support unit continue to operate. Hot air at 38°C, a wind speed of 3 m / s, and a rolling bed speed of 1 r / min is introduced into the wet carrot seed pellets to dry them until the dry basis moisture content is ≤8%. Drying is then stopped, yielding pre-dried carrot seed pellets. (5) Resuscitation treatment The pre-dried carrot seed pellets were left to stand at 25°C for 30 minutes for a slow tempering treatment to obtain dried carrot seed pellets. The carrot seed pellets provided in this embodiment are named "M2H38-H38".

[0032] Example 2: A method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control includes the following steps: (1) Preparation of wet carrot seed pellets In this embodiment, the same batch of naked carrot seeds was used as raw material, and damaged seeds, shriveled seeds, and impurities were removed. 100g of carrot seeds were poured into the coating pan of the RH-325 seed pelleting machine, and 3350g of carrot seed powder was weighed out. The seed pelleting machine was started, and the powder feeding speed was adjusted to 200r / min. The carrot seed powder was slowly added, while water was sprayed into the coating pan simultaneously. The mass ratio of carrot seeds, carrot seed powder, and water was 1:33.5:7, resulting in wet carrot seed pellets. (2) Screening of wet carrot seed pellets During the pelleting process, the pelleted seeds were sieved using 3.5mm and 4.0mm standard grain sieves. When the pelleted seed particle size reached the range of 3.5–4.0mm, the pelleting operation was stopped, and wet carrot seed pellets with a particle size of 3.5–4.0mm were obtained by sieving. (3) Microwave hot air pretreatment The sieved wet carrot seed pellets are placed in a drying device and kept in a rolling state during the drying process; hot air at 34°C and 3 m / s is introduced into the wet carrot seed pellets, and microwave power density of 1.5 W / g is applied at the same time, with a pretreatment time of 4 min and a rolling bed speed of 1 r / min. (4) Hot air drying After the microwave hot air pretreatment is completed, the microwave treatment is stopped, but the hot air supply unit and the rolling bed support unit continue to operate. Hot air at 34℃, a wind speed of 3m / s, and a rolling bed speed of 1r / min is introduced into the wet carrot seed pellets to dry them until the dry basis moisture content is ≤8%. Drying is then stopped, yielding pre-dried carrot seed pellets. (5) Resuscitation treatment The pre-dried carrot seed pellets were left to stand at 25°C for 30 minutes for a slow tempering treatment to obtain dried carrot seed pellets. The carrot seed pellets provided in this embodiment are named "M4H34-H34".

[0033] Example 3: A method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control includes the following steps: (1) Preparation of wet carrot seed pellets In this embodiment, the same batch of naked carrot seeds was used as raw material, and damaged seeds, shriveled seeds, and impurities were removed. 100g of carrot seeds were poured into the coating pan of the RH-325 seed pelleting machine, and 3350g of carrot seed powder was weighed out. The seed pelleting machine was started, and the powder feeding speed was adjusted to 200r / min. The carrot seed powder was slowly added, while water was sprayed into the coating pan simultaneously. The mass ratio of carrot seeds, carrot seed powder, and water was 1:33.5:7, resulting in wet carrot seed pellets. (2) Screening of wet carrot seed pellets During the pelleting process, the pelleted seeds were sieved using 3.5mm and 4.0mm standard grain sieves. When the pelleted seed particle size reached the range of 3.5–4.0mm, the pelleting operation was stopped, and wet carrot seed pellets with a particle size of 3.5–4.0mm were obtained by sieving. (3) Microwave hot air pretreatment The sieved wet carrot seed pellets are placed in a drying device and kept in a rolling state during the drying process; hot air at 38°C and 3 m / s is introduced into the wet carrot seed pellets, and microwave power density of 1.5 W / g is applied at the same time, the pretreatment time is 4 min, and the rolling bed speed is 1 r / min. (4) Hot air drying After the microwave hot air pretreatment is completed, the microwave treatment is stopped, but the hot air supply unit and the rolling bed support unit continue to operate. Hot air at 38°C, a wind speed of 3 m / s, and a rolling bed speed of 1 r / min is introduced into the wet carrot seed pellets to dry them until the dry basis moisture content is ≤8%. Drying is then stopped, yielding pre-dried carrot seed pellets. (5) Resuscitation treatment The pre-dried carrot seed pellets were left to stand at 25°C for 30 minutes for a slow tempering treatment to obtain dried carrot seed pellets. The carrot seed pellets provided in this embodiment are named "M4H38-H38".

[0034] Example 4: A method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control includes the following steps: (1) Preparation of wet carrot seed pellets In this embodiment, the same batch of naked carrot seeds was used as raw material, and damaged seeds, shriveled seeds, and impurities were removed. 100g of carrot seeds were poured into the coating pan of the RH-325 seed pelleting machine, and 3350g of carrot seed powder was weighed out. The seed pelleting machine was started, and the powder feeding speed was adjusted to 200r / min. The carrot seed powder was slowly added, while water was sprayed into the coating pan simultaneously. The mass ratio of carrot seeds, carrot seed powder, and water was 1:33.5:7, resulting in wet carrot seed pellets. (2) Screening of wet carrot seed pellets During the pelleting process, the pelleted seeds were sieved using 3.5mm and 4.0mm standard grain sieves. When the pelleted seed particle size reached the range of 3.5–4.0mm, the pelleting operation was stopped, and wet carrot seed pellets with a particle size of 3.5–4.0mm were obtained by sieving. (3) Microwave hot air pretreatment The sieved wet carrot seed pellets are placed in a drying device and kept in a rolling state during the drying process; hot air at 42°C and 3 m / s is introduced into the wet carrot seed pellets, and microwave power density of 1.5 W / g is applied at the same time, the pretreatment time is 4 min, and the rolling bed speed is 1 r / min. (4) Hot air drying After the microwave hot air pretreatment is completed, the microwave treatment is stopped, but the hot air supply unit and the rolling bed support unit continue to operate. Hot air at 42℃, a wind speed of 3m / s, and a rolling bed speed of 1r / min is introduced into the wet carrot seed pellets to dry them until the dry basis moisture content is ≤8%. Drying is then stopped, yielding pre-dried carrot seed pellets. (5) Resuscitation treatment The pre-dried carrot seed pellets were left to stand at 25°C for 30 minutes for a slow tempering treatment to obtain dried carrot seed pellets. The carrot seed pellets provided in this embodiment are named "M4H42-H42".

[0035] Example 5: A method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control includes the following steps: (1) Preparation of wet carrot seed pellets In this embodiment, the same batch of naked carrot seeds was used as raw material, and damaged seeds, shriveled seeds, and impurities were removed. 100g of carrot seeds were poured into the coating pan of the RH-325 seed pelleting machine, and 3350g of carrot seed powder was weighed out. The seed pelleting machine was started, and the powder feeding speed was adjusted to 200r / min. The carrot seed powder was slowly added, while water was sprayed into the coating pan simultaneously. The mass ratio of carrot seeds, carrot seed powder, and water was 1:33.5:7, resulting in wet carrot seed pellets. (2) Screening of wet carrot seed pellets During the pelleting process, the pelleted seeds were sieved using 3.5mm and 4.0mm standard grain sieves. When the pelleted seed particle size reached the range of 3.5–4.0mm, the pelleting operation was stopped, and wet carrot seed pellets with a particle size of 3.5–4.0mm were obtained by sieving. (3) Microwave hot air pretreatment The sieved wet carrot seed pellets are placed in a drying device and kept in a rolling state during the drying process; hot air at 38°C and 3 m / s is introduced into the wet carrot seed pellets, and microwave power density of 1.5 W / g is applied at the same time, with a pretreatment time of 6 min and a rolling bed speed of 1 r / min. (4) Hot air drying After the microwave hot air pretreatment is completed, the microwave treatment is stopped, but the hot air supply unit and the rolling bed support unit continue to operate. Hot air at 38°C, a wind speed of 3 m / s, and a rolling bed speed of 1 r / min is introduced into the wet carrot seed pellets to dry them until the dry basis moisture content is ≤8%. Drying is then stopped, yielding pre-dried carrot seed pellets. (5) Resuscitation treatment The pre-dried carrot seed pellets were left to stand at 25°C for 30 minutes for a slow tempering treatment to obtain dried carrot seed pellets. The carrot seed pellets provided in this embodiment are named "M6H38-H38".

[0036] Comparative Example 1: A method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control includes the following steps: (1) Preparation of wet carrot seed pellets In this embodiment, the same batch of naked carrot seeds was used as raw material, and damaged seeds, shriveled seeds, and impurities were removed. 100g of carrot seeds were poured into the coating pan of the RH-325 seed pelleting machine, and 3350g of carrot seed powder was weighed out. The seed pelleting machine was started, and the powder feeding speed was adjusted to 200r / min. The carrot seed powder was slowly added, while water was sprayed into the coating pan simultaneously. The mass ratio of carrot seeds, carrot seed powder, and water was 1:33.5:7, resulting in wet carrot seed pellets. (2) Screening of wet carrot seed pellets During the pelleting process, the pelleted seeds were sieved using 3.5mm and 4.0mm standard grain sieves. When the pelleted seed particle size reached the range of 3.5–4.0mm, the pelleting operation was stopped, and wet carrot seed pellets with a particle size of 3.5–4.0mm were obtained by sieving. (3) Hot air drying During the drying process, the wet carrot seed pellets are kept in a rolling state. Hot air with a temperature of 38°C, a wind speed of 3m / s, and a rolling bed speed of 1r / min is introduced into the wet carrot seed pellets in step (2) to dry the wet carrot seed pellets until the dry basis moisture content is ≤8%. Then, the drying is stopped to obtain pre-dried carrot seed pellets. (4) Resuscitation treatment The pre-dried carrot seed pellets were left to stand at 25°C for 30 minutes for a slow tempering treatment to obtain dried carrot seed pellets. The carrot seed pellets provided in this embodiment are named "H38".

[0037] Comparative Example 2: The difference from Example 3 is that in step (1), the mass ratio of carrot seeds, carrot seed powder, and water is 1:33.5:6.83. The pellets obtained in Comparative Example 2 are as follows: Figure 2 As shown in Figure A.

[0038] Comparative Example 3: The difference from Example 3 is that in step (1), the mass ratio of carrot seeds, carrot seed powder, and water is 1:33.5:8.11. The pellets obtained in Comparative Example 3 are as follows: Figure 2 As shown in B.

[0039] Depend on Figure 2 A and Figure 2As shown in B, under the condition that the ratio of carrot seeds to pelleting powder is the same, the amount of water added has a significant impact on the pelleting state of carrot seeds. In Comparative Example 2, the mass ratio of carrot seeds, carrot seed pelleting powder, and water is 1:33.5:6.83, which is lower than the 1:33.5:7 ratio in Example 3. The resulting pellets are generally smaller, with insufficient particle size growth, and some pellets do not reach the target particle size range. In Comparative Example 3, the mass ratio of carrot seeds, carrot seed pelleting powder, and water is 1:33.5:8.11, which is higher than the amount of water added in Example 3. The wet pellets are prone to adhesion and agglomeration, accompanied by deformed particles and powdery debris. This indicates that when the amount of water added is too low or too high, it is not conducive to the particle size growth and uniformity of carrot seed pellets. The 1:33.5:7 mass ratio used in Example 3 is more conducive to the stable coating of pelleting powder on the surface of individual carrot seeds, thereby obtaining carrot seed pellets with more concentrated particle size and better forming state.

[0040] Detection Example 1: To evaluate the effects of the method of this invention on the drying efficiency, physical quality, and germination performance of carrot seed pellets, carrot seed pellets obtained from different treatment groups were tested. The test items included drying time, final moisture content, pellet hardness, pellet brittleness, germination potential, germination rate, germination index, and vigor index.

[0041] (1) Drying time determination: Start timing from the beginning of drying until the moisture content of the dry sample drops to ≤8%, and record the total drying time (min).

[0042] (2) Determination of dry basis moisture content: The weighing method was used. A certain mass of pellet sample was accurately weighed and dried in a drying device until constant weight. The moisture content (dry basis) was calculated based on the mass difference before and after drying. Dry basis moisture content (%) = (wet weight - dry weight) / dry weight × 100%. After testing, the moisture content of the wet carrot seed pellets before entering the drying device was 35% to 40%.

[0043] (3) Moisture Ratio Calculation: During the drying process, the dry basis moisture content of the pellets was measured every 10 minutes, and calculated according to MR=Mt / M0. The moisture ratio was calculated based on the dry basis moisture content at each time point during different drying processes, and a curve of moisture ratio changing with drying time was plotted. The results are as follows: Figure 6 As shown; Figure 6 The Henderson and Pabis model fitting curves are used to characterize the fitting trend of moisture ratio as a function of drying time.

[0044] (4) Hardness test of pellets: Using the physical performance tester TA.XTC-16 of Baosheng Technology equipped with TA / 50 cylindrical probe, 20 pellets were randomly selected from each treatment group, and the maximum pressure (N) when the pellets were crushed was measured one by one. The average value was taken as the hardness of the pellets.

[0045] (5) Pellet brittleness determination: Using the same method as the hardness determination, the deformation-pressure curve of the pellet when it is crushed is recorded, and the brittleness value is calculated from the fracture point characteristics in the curve. The larger the brittleness value, the easier it is for the pellet to undergo brittle fracture under stress; the smaller the brittleness value, the stronger the resistance to brittle fracture and the better the structural stability of the pellet.

[0046] (6) Germination test: 300 pelleted seeds were taken from each treatment group, divided into 3 replicates of 100 seeds per replicate, and placed in 200-cell trays 4 cm deep, with 3 seeds per cell. The trays were placed in natural light at 25℃ for the germination test. Appropriate amounts of water were added daily to keep the substrate moist, and the number of germinated seeds was recorded on days 1, 4, 7, 10, and 14 (germination was defined as the emergence of the radicle from the soil). The germination phenomena of pellets under different drying treatments are as follows: Figure 7 As shown in Table 2, the germination rate, germination index, and vigor index data are all based on the results measured or statistically analyzed on day 14; the corresponding change data in Table 3 are calculated based on the relevant data from day 14 in Table 2. The formulas for calculating germination potential, germination rate, germination index, and vigor index are as follows: Germination potential (%) = (Number of seeds that germinated normally on day 7 / Number of seeds tested) × 100% Germination rate (%) = (Number of normally germinated seeds on day 14 / Number of seeds tested) × 100% Germination Index (GI) = Σ (Number of germinated seeds on day t / Corresponding number of germination days) Vigor Index (VI) = Germination Index × Average Seedling Length (mm) Table 1. Effects of different drying treatments on drying efficiency and physical quality of carrot seed pellets.

[0047] Table 2 Effects of different drying treatments on the germination performance of carrot seed pellets

[0048] Furthermore, to facilitate the evaluation of the substantial technical effects of this invention compared to hot air drying alone, the changes in each embodiment relative to Comparative Example 1 are listed in Table 3. In Table 3, the reduction in drying time is calculated based on the total drying time; changes in germination potential and germination rate are expressed as percentage points; changes in germination index and vigor index are expressed as relative change rates relative to Comparative Example 1. The data in Tables 2 and 3, based on measurements or statistics taken on day 14, have been used as important criteria for evaluating germination performance. In Example 4 (M4H42-H42), although some seed radicles were observed to be white on day 14, they were included in the germination rate statistics according to the germination judgment criteria; however, this treatment did not produce normal seedlings suitable for length measurement, and the seedling length was below the stable measurement range of this experiment. Therefore, in the calculation of the vigor index, the average length of the seedlings was counted as 0, and the vigor index was recorded as 0.

[0049] Table 3. Changes in technical effectiveness of different treatment groups relative to Comparative Example 1.

[0050] From Table 1, Table 2, Figure 7 As shown in Table 3, compared with Comparative Example 1 (H38), microwave hot air pretreatment combined with hot air drying can shorten the drying time of carrot seed pellets to varying degrees and have different effects on the physical quality and germination performance of the pellets. Figure 6 The trend of moisture ratio change with drying time indicates that microwave hot air pretreatment can promote the migration of moisture from inside carrot seed pellets to the outside, accelerate the decrease of pellet moisture ratio, and thus improve the early drying rate.

[0051] Example 1 (M2H38-H38) showed a 16.67% reduction in drying time compared to Comparative Example 1, with higher germination rate, germination index, and vigor index. This indicates that 2 minutes of microwave pretreatment under 38℃ hot air conditions can improve drying efficiency and germination performance to some extent. Example 2 (M4H34-H34) also showed a 16.67% reduction in drying time, but on day 14, the germination rate, germination index, and vigor index were all lower than Comparative Example 1. This suggests that while 4 minutes of microwave pretreatment under 34℃ hot air conditions can shorten drying time, the overall germination effect is insufficient. Example 3 (M4H38-H38) showed a 33.33% reduction in drying time, with a 12.25 percentage point increase in germination rate on day 14 compared to Comparative Example 1, and increases in germination index and vigor index by 72.06% and 72.86%, respectively. This indicates that this treatment can improve drying efficiency while maintaining the germination performance of carrot seed pellets.

[0052] Example 4 (M4H42-H42) showed the shortest drying time among all examples, with a 50.00% reduction in drying time. However, its germination rate and germination index on day 14 were lower than those of Comparative Example 1. Although some seed radicles were observed to emerge on day 14, no normal seedlings suitable for length measurement were formed. Therefore, the average seedling length was recorded as 0, and the vigor index was recorded as 0. This result indicates that while microwave hot air pretreatment combined with hot air drying at 42℃ can significantly accelerate the dehydration process, it may adversely affect subsequent seedling elongation. Example 5 (M6H38-H38) showed a 41.67% reduction in drying time, but its germination rate on day 14 was lower than that of Comparative Example 1. This suggests that extending the microwave pretreatment time to 6 minutes at 38℃, while further shortening the drying time, may not be conducive to maintaining the final germination rate.

[0053] Considering factors such as drying time, dry basis moisture content, pellet hardness, pellet brittleness, germination potential, germination rate, germination index, and vigor index, under the conditions of this embodiment, Example 3 (M4H38-H38) exhibits a better balance between drying efficiency and germination performance, and can be considered as a preferred embodiment of the present invention.

[0054] Detection Example 2: To further illustrate the effect of the method of the present invention on the heat uniformity during the drying process of carrot seed pellets, an infrared thermal imager (VT08, Fluke, USA) was used to collect the surface temperature distribution of carrot seed pellets under different drying methods in a non-contact manner, and the temperature uniformity coefficient CU and the temperature variation coefficient CV were used to evaluate the temperature uniformity during the drying process.

[0055] The specific method is as follows: infrared thermal imaging was performed on the carrot seed pellets of Comparative Example 1 (H38) which was treated with hot air drying alone and Example 3 (M4H38-H38) which was treated with microwave hot air pretreatment combined with hot air drying.

[0056] For Comparative Example 1 (H38), the drying start time was taken as 0 min, and infrared thermal images of the surface of the carrot seed pellet material layer were collected at 20 min, 40 min and 60 min of drying, respectively, as temperature distribution maps of the early, middle and late stages of drying for the individual hot air drying treatment.

[0057] For Example 3 (M4H38-H38), taking the moment when microwave and hot air are turned on simultaneously as 0 min, an infrared thermal image of the surface of the carrot seed pellet layer is collected at the end of the microwave-hot air pretreatment, which serves as the temperature distribution map in the microwave-hot air pretreatment stage. Subsequently, the microwave generating unit is turned off, and only the hot air supply unit and the rolling bed carrying unit are kept running. Infrared thermal images are collected at 20 min, 40 min, and 60 min during the subsequent hot air drying respectively, which serve as the temperature distribution maps in the early, middle, and late stages of the subsequent hot air drying respectively.

[0058] During the shooting process, the distance between the infrared thermal imager and the surface of the carrot seed pellets is 20 - 50 cm, and the angle between the optical axis of the infrared thermal imager lens and the normal line of the surface of the carrot seed pellets is 30° - 60°. After obtaining the infrared thermal image, taking the area where the carrot seed pellet layer is located in each infrared thermal image as the overall analysis area, the temperature data within this overall analysis area is extracted using the analysis software supporting the infrared thermal imager. The temperature data includes the temperature values, the highest temperature, the lowest temperature, and the average temperature of each temperature data point within the overall analysis area. According to the extracted temperature data, the temperature uniformity coefficient CU and the temperature variation coefficient CV of the carrot seed pellet layer in different drying stages are calculated.

[0059] (1) The calculation formula for the temperature uniformity coefficient CU is: [1 - (highest temperature - lowest temperature) / (2 × average temperature)] × 100%; (2) The calculation formula for the temperature variation coefficient CV is: (standard deviation of temperature / average temperature) × 100%.

[0060] Table 4 Evaluation results of the temperature uniformity on the surface of carrot seed pellets under different drying methods

[0061] From Figure 8 and Table 4, it can be seen that there are certain temperature differences on the surface of the carrot seed pellets during the hot air drying process in Comparative Example 1 (H38), and the color change in the local area is relatively obvious, indicating that the temperature distribution uniformity of the material layer during single hot air drying is relatively poor. Compared with hot air drying, during the microwave-hot air drying process in Example 3 (M4H38-H38), the overall temperature distribution on the surface of the carrot seed pellets is more continuous, the temperature uniformity coefficient is higher, and the temperature variation coefficient is lower, indicating that the synergistic effect of microwave, hot air, and the rolling state can improve the heat reception uniformity on the surface of the pellets, reduce the risk of local overheating, and thus is beneficial to reducing the thermal damage and oxidation damage caused to the carrot seed pellets during the drying process.

[0062] Test Example 3: The wet carrot seed pellets obtained by sieving the wet carrot seed pellets obtained in step (2) of Example 3 (M4H38-H38) were subjected to molding quality testing. For particle size uniformity testing, 20 carrot seed pellets were randomly selected for each replicate, with a total of 3 replicates. The particle size of each pellet was measured, and the number of pellets with a particle size in the range of 3.5–4.0 mm was counted. Particle size uniformity was calculated as "number of pellets with a particle size in the range of 3.5–4.0 mm / total number of pellets tested × 100%", and the average value of the 3 replicates was taken.

[0063] For testing seed content, single-seed content, and lysis rate, 100 carrot seed pellets were randomly selected as test samples. The presence and quantity of carrot seeds inside the pellets were observed through peeling or immersion in water to induce lysis. Specifically, the seed content rate was the percentage of pellets containing carrot seeds out of the total number of pellets tested; the single-seed content rate was the percentage of pellets containing a single carrot seed out of the total number of pellets tested; and the lysis rate was the percentage of pellets that lysis within 5 minutes of immersion in water out of the total number of pellets tested.

[0064] The test results show that Figure 3 The obtained carrot seed pellets had a particle size uniformity of 96.66%, a seed content of 96%, a single seed content of 96%, and a cleavage rate of 100%. Figure 4 This image shows the seed content and single seed rate inside carrot seed pellets after they have been peeled off. The percentages in the image were calculated by statistical analysis of each seed. The image is used to show representative observation conditions. Figure 5 This is an observation of the lysis state of carrot seed pellets after soaking in water for 5 minutes.

[0065] Detection Example 4: To further illustrate the effect of the method of the present invention on the structural integrity of carrot seed pellets, scanning electron microscopy was used to observe the microstructure of naked carrot seeds and carrot seed pellets dried by microwave hot air in Example 3. Figure 9 As shown. The observation areas include the surface of the naked carrot seed, the surface of the dried pellets, the cross-section of the pellets, the powder coating layer, and the interface between the seed and the coating layer. The focus is on observing the continuity of the shell, the distribution of pores, the presence of microcracks, and the bonding state between the seed and the coating layer. SEM results can be used to illustrate the role of the pellets in maintaining structural integrity during the forming process.

[0066] It should be noted that the specific embodiments are merely representative examples of the present invention, and the technical solution of the present invention is obviously not limited to the above embodiments, and there can be many variations. Those skilled in the art who obtain the present invention based on its explicit disclosure or without objection from the written description should consider it to be within the scope of protection of this patent.

Claims

1. A method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control, characterized in that, Includes the following steps: (1) Preparation of wet carrot seed pellets Using the same batch of naked carrot seeds as raw materials, damaged seeds, shriveled seeds and impurities are removed to obtain carrot seeds to be pelletized; the carrot seeds are poured into a seed pelleting machine, the seed pelleting machine is started, carrot seed powder is slowly added, and water is added at the same time; (2) Screening of wet carrot seed pellets During the pelleting process, a standard grain sieve is used to sieve the pelleted seeds to obtain wet carrot seed pellets after sieving. (3) Microwave hot air pretreatment The sieved wet carrot seed pellets are placed in a drying device and kept in a rolling state during the drying process for microwave hot air pretreatment. (4) Hot air drying After the microwave hot air pretreatment is completed, the microwave treatment is stopped, and the hot air treatment is carried out to obtain pre-dried carrot seed pellets. (5) Resuscitation treatment The carrot seed pellets are obtained by slow tempering after pre-drying.

2. The method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control according to claim 1, characterized in that, In step (1), the mass ratio of carrot seeds, carrot seed powder and water is 1:(30-35):(6-8).

3. The method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control according to claim 2, characterized in that, In step (1), the mass ratio of carrot seeds, carrot seed powder and water is 1:33.5:

7.

4. The method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control according to claim 1, characterized in that, In step (1), the powder feeding speed of the seed pelleting machine is 200-300 r / min.

5. The method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control according to claim 1, characterized in that, In step (1), water is added by spraying.

6. The method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control according to claim 1, characterized in that, In step (2), the standard sieve is a 3.5mm and a 4.0mm standard sieve, and wet carrot seed pellets with a particle size of 3.5 to 4.0mm are obtained by sieving.

7. The method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control according to claim 1, characterized in that, In steps (3) and (4), an infrared thermal imager is used to collect the surface temperature distribution of the carrot seed pellet material layer, and the area where the carrot seed pellet material layer is located in the infrared thermal image is used as the overall analysis area to calculate the temperature uniformity coefficient and temperature variation coefficient to evaluate the uniformity of pellet heating.

8. A type of carrot seed pellet, characterized in that, The carrot seed pellets were prepared by the method for preparing carrot seed pellets based on single-seed nucleation and wet sieving control as described in any one of claims 1 to 7.

9. The carrot seed pellets according to claim 8, characterized in that, The carrot seed pellets shall have a particle size uniformity of not less than 95%, a seed content of not less than 90%, and a single seed rate of not less than 90%.

10. The application of carrot seed pellets prepared by the preparation method according to any one of claims 1 to 7, or carrot seed pellets according to any one of claims 8 to 9, in mechanized precision seeding.

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