Seed coating method and coated seed
By using low Bloom value and low viscosity gelatin to coat seeds, the problem of non-biodegradable seed coating materials is solved, achieving environmentally friendly seed protection and promoting seed growth.
Patent Information
- Application Number
- CN202480046945.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-07-20
- Filing Date
- 2024-04-30
- Publication Date
- 2026-03-03
AI Technical Summary
Existing seed coating materials are non-biodegradable, leading to soil and groundwater pollution.
Using gelatin with a Bloom value of about 150 g or less and a viscosity of about 2.5 mPas or less as a coating solution, a gelatin-based coating is formed on the seed surface by spraying and drying.
It forms a wear-resistant, biodegradable seed coating, promotes seed growth, and releases active ingredients after sowing, reducing environmental pollution.
Smart Images
Figure CN121604879A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a seed coating method.
[0002] The present invention also relates to a seed coated according to the method. Background Technology
[0003] Seed coating is known to be done before sowing. This coating serves two purposes: firstly, it protects the seeds during storage and transportation. However, its primary function is to promote growth by adding plant nutrients and / or crop protectants, which are released from the coating after sowing.
[0004] Known seed coating materials typically contain synthetic polymers such as polyvinyl acetate, polyvinyl alcohol, polyvinylpyrrolidone, or polyacrylate, which are non-biodegradable or poorly biodegradable, thus leading to environmental pollution of soil and groundwater, particularly in the form of microplastics. Summary of the Invention
[0005] The purpose of this invention is to provide a method for forming a biodegradable seed coating.
[0006] According to the present invention, this objective is achieved by a seed coating method, which includes the following steps: - Provides an aqueous coating solution containing a Bloom value of about 150 g or less and a Pa2+ of about 2.5 mPa. A gelatin with a viscosity of s or lower, wherein the viscosity is obtained by measuring a 6.67% gelatin solution at 60°C; and - The coating solution is applied to the seed surface and the coating solution is dried to obtain a gelatin-based coating on the seed.
[0007] In the method of this invention, the seeds are provided with a gelatin-based coating. The use of gelatin has long been known in various technical fields, particularly in the food and pharmaceutical industries. As a product extracted from collagen in animal connective tissue, gelatin is completely biodegradable and harmless in terms of health and ecology.
[0008] The physical and rheological properties of gelatin are characterized, in particular, by Bloom value (i.e., gel strength) and viscosity. Standard methods for determining these two parameters are described in the GME monograph "Standardized Methods for the Testing of Edible Gelatin". All Bloom values and viscosities mentioned within the scope of this invention should be determined according to these standard methods.
[0009] For seeds to be coated with gelatin, the gelatin must exhibit sufficient gelling and film-forming abilities to form an effective protective layer on the seed particles. On the other hand, the aqueous coating solution should be easily processed using existing coating equipment, and in particular, should have good sprayability. These two requirements for the properties of the gelatin used are contradictory. However, within the scope of this invention, it has been surprisingly found that gelatin with a Bloom value of about 150 g or less and a pH of about 2.5 mPa is suitable. Gelatin with a viscosity of 5% or lower is ideal for seed coating. This coating method can be performed using known equipment and forms an abrasion-resistant coating on the seed grains. Furthermore, the dried coating is non-sticky, thus giving the seeds a free-flowing quality conducive to dispersal.
[0010] In the method according to the invention, the application of the coating solution to the seed surface and the drying of the coating solution are carried out simultaneously in a substantially continuous process. Advantageously, the coating solution is sprayed onto the seed surface, for which various known coating equipment can be used, particularly rotary drum coaters, spin coaters, coating pans, or fluidized bed dryers. The spraying rate of the aqueous coating solution is typically in the range of 200 g / h to 500 g / h.
[0011] The coating solution is preferably applied, particularly sprayed, to the seed surface at a temperature of about 50°C or higher, more preferably about 55°C or higher. At this temperature, the coating solution has a sufficiently low viscosity for good processing. Higher temperatures above 60°C are generally unfavorable because they may cause thermal degradation of the gelatin.
[0012] The coating solution is preferably applied and dried at a temperature of about 30°C to about 60°C. By evaporating the water in the coating solution at these temperatures, a gelatin-based coating is obtained on the seeds.
[0013] The amount of coating solution applied to the seeds can vary over a relatively wide range depending on the seed type and the exact purpose of the coating. Typically, the coating solution is applied to the seed surface at a rate of about 50 g to about 1,000 g per kilogram of seeds.
[0014] According to the present invention, the gelatin used in the coating solution has a strength of about 2.5 mPa. A viscosity of s or lower. More preferably, the viscosity of gelatin is approximately 2.3 mPa. s or lower, especially about 2.1 mPa The viscosity was s or lower, and each viscosity was determined at 60°C using a 6.67% gelatin solution.
[0015] Gelatin can be produced from collagen-containing starting materials from the skin or bones of mammals. Pork skin is a particularly advantageous starting material. Pork skin gelatin has been found to be particularly useful within the scope of this invention.
[0016] The gelatin can be type A or type B gelatin, or a mixture thereof. For example, gelatin with a Bloom value in the range of about 100 g and a Pa value of about 2 mPa is particularly suitable for the purposes of this invention. Type A gelatin from acid-digested pigskin with a viscosity within the s range. However, Type B gelatin with corresponding viscosity and Bloom value, such as bovine bone gelatin, can also be used.
[0017] Various types of gelatin can also be characterized based on molecular weight or molecular weight distribution, with molecular weight being somewhat related to the Bloom value. The gelatin used in the methods of this invention preferably has a weight-average molecular weight of about 20 kDa to about 100 kDa, more preferably about 39 kDa to about 84 kDa. The weight-average molecular weight of gelatin is determined, in particular, by gel permeation chromatography.
[0018] To further optimize the rheological properties of the coating solution, depending on the type of gelatin used, it may be advantageous if the coating solution also contains one or more protein hydrolysates. These hydrolysates are preferably selected from collagen hydrolysates, plant protein hydrolysates, and mixtures thereof. Preferred plant proteins for preparing the respective hydrolysates are, in particular, soy protein, wheat protein, and whey protein.
[0019] Collagen hydrolysates are prepared from gelatin or directly from collagen-containing starting materials through chemical or enzymatic hydrolysis. Due to their low molecular weight, collagen hydrolysates do not possess gelling properties. The collagen hydrolysates used in the methods of this invention preferably have a weight-average molecular weight of about 0.5 kDa to about 18 kDa, more preferably about 2 kDa to about 5 kDa, and particularly about 2.5 kDa to about 3.5 kDa.
[0020] By replacing a portion of the gelatin with a collagen hydrolysate or another protein hydrolysate, the molecular weight distribution of the total peptides contained in the coating solution can be intentionally influenced. Based on this viewpoint, it is generally preferred that the coating solution contains at least about 10% by weight of gelatin and optionally a protein hydrolysate with a molecular weight up to 18 kDa, relative to the total weight of the gelatin and protein hydrolysate.
[0021] More preferably, the coating solution comprises at least about 40% by weight of gelatin and optionally protein hydrolysates with a molecular weight up to 39 kDa, relative to the total weight of the gelatin and protein hydrolysates.
[0022] In a preferred embodiment of the invention, the coating solution comprises a total of about 5% to about 30% by weight, preferably about 8% to about 20% by weight, of gelatin and optionally protein hydrolysates.
[0023] The coating solution may also contain one or more cross-linking agents for gelatin, preferably selected from tannins, polyphenols, and aldehydes such as glyoxal, glutaraldehyde, and formaldehyde. Cross-linking of the gelatin can affect the solubility and water absorption capacity of the coating, and the cross-linked gelatin retains its biodegradability, even over a potentially long period. Natural cross-linking agents, such as tannins or tannin-containing plant extracts, are preferred.
[0024] Furthermore, it may be advantageous if the coating solution also contains one or more plasticizers, preferably selected from sugar alcohols and sugars, particularly glycerol, sorbitol, sorbitan, mannitol, maltitol, xylitol, glucose, and sucrose, or from propylene glycol, polypropylene glycol, and polyethylene glycol. Such plasticizers can improve the flexibility of the coating and reduce brittleness, as is known, for example, from the field of soft gelatin capsules.
[0025] It is particularly advantageous if the coating solution also contains one or more active ingredients, preferably selected from plant nutrients, growth promoters, and crop protectants such as insecticides and fungicides. These active ingredients in the coating are released into the soil after sowing and can purposefully promote seed germination and plant growth. In addition to these active ingredients, gelatin-based coatings also promote growth due to their water-absorbing capacity: after sowing, gelatin can absorb several times its own weight in water from the soil and form a hydrogel, thereby optimizing the water supply to the seed particles.
[0026] In addition to gelatin, water, and the aforementioned components, the coating solution may contain other components to purposefully adjust the properties or functions of the coating. Specifically, the coating solution may contain one or more additives and / or fillers selected from pigments such as titanium dioxide and iron oxide; minerals such as bentonite and kaolin; biodegradable fibers such as cellulose and keratin; polysaccharides such as starch and chitosan; or mixtures thereof.
[0027] The method according to the invention is applicable to coating any type of seed. Preferably, the seeds are selected from cereal seeds, such as wheat, rye, barley, oats, corn, rice, and millet; from legume seeds, such as kidney beans, peas, lentils, soybeans, chickpeas, sweet peas, and lupins; from pseudocereal seeds, such as buckwheat, quinoa, and amaranth; or from oilseeds, such as rapeseed, flax, and sunflower. The method of the invention can also be used for coating the seeds of other types of crops or ornamental plants.
[0028] The present invention also relates to the use of an aqueous coating solution for coating seeds, wherein the coating solution comprises a Bloom value of about 150 g or less and a Pa2+ of about 2.5 mPa. Gelatin with a viscosity of s or lower, wherein the viscosity is obtained by measuring a 6.67% gelatin solution at 60°C.
[0029] The specific advantages and preferred embodiments of the uses of the present invention have been described in conjunction with the method of the present invention.
[0030] These and other advantages of the present invention will be explained in more detail with reference to the following practical embodiments, but these embodiments do not limit the subject matter of the invention in any way. Detailed Implementation
[0031] Example
[0032] Type of gelatin and collagen hydrolysates used
[0033] The commercially available gelatin types listed in Table 1 are used in the following practical embodiments for implementing the method of the present invention. These gelatin types are type A gelatin derived from pigskin or cowhide (cowhide).
[0034] Table 1
[0035] For gelatin-type PS100, the molecular weight distribution determined by gel permeation chromatography is shown in Table 2: Table 2
[0036] This distribution shows that the preferred gelatin type contains a high proportion of relatively low molecular weight peptides with molecular weights up to 18 kDa, exceeding approximately 28% by weight in the case of PS100. The proportion of these low molecular weight peptides in the coating solution can be further increased by adding collagen hydrolysates, which also leads to a decrease in the Bloom value and viscosity of the corresponding gelatin and collagen hydrolysate mixture.
[0037] In the following practical examples, a mixture of gelatin PS100 as shown in Table 3 and collagen hydrolysate (obtained under the name GELITA Peptiplus) with a weight-average molecular weight of 3.2 kDa was used: Table 3
[0038] Example 1: Seed coating using a coating container
[0039] To coat seeds using coating containers, aqueous coating solutions with different gelatin types and (in some cases) varying gelatin concentrations were used, as shown in Table 4. The coating solutions also contained pigments (titanium dioxide) to make the seed coating visually identifiable.
[0040] Table 4
[0041] Using these coating solutions, 150 g of seeds (chickpeas or green peas) were coated in a coating pan. The solution was kept liquid at approximately 60°C (above the gelation temperature) and sprayed onto the seeds. The processing temperature in the coating pan was 20°C to 24°C.
[0042] The coating solution is sufficient to completely coat and color the seeds. It forms a relatively thick coating with excellent adhesion to the seeds and forms a stable film that dries well, is abrasion-resistant, and non-sticky.
[0043] Example 2: Seed coating using a rotary drum coating machine
[0044] To coat seeds using a rotary drum coating machine with a spray nozzle from Glatt, a mixture of 18 g of gelatin PS100 and 3-5 g of pigment (FeO) was used. x An aqueous coating solution consisting of 82 g of water and 82 g of water.
[0045] The temperature of the spraying solution here is 50-66℃, the spraying rate is 200 g / h, and the processing temperature in the rotary drum coating machine is 31-35℃.
[0046] In this case, only 5% to 10% of the total coating solution is sufficient to fully coat and color 100 g of seeds (chickpeas or green peas). A full coating solution results in the formation of a thick coating shell, which adheres extremely well to the seeds and forms a stable film that dries very well.
[0047] Alternatively, a 1:10 diluted gelatin solution (i.e., 1.8 g gelatin PS100, 98.2 g water, and 3-5 g pigment) can be used to fully coat and color 100 g of seeds under the same process parameters, although the time required is significantly longer.
[0048] Example 3: Coating with gelatin and collagen hydrolysate
[0049] In these embodiments, a mixture of gelatin PS100 and collagen hydrolysate from Table 3 above was used for seed coating using a rotary drum coating machine. FeO was used. x As a pigment, the specific composition and process parameters of the coating solution are shown in Table 5: Table 5
[0050] The coating operation in the rotary drum coating machine is as described in Example 2. The addition of collagen hydrolysate reduces the viscosity and gelation temperature of the coating solution, thereby reducing the risk of pipe blockage due to excessively low spray solution temperature.
[0051] In all Examples 3.1 to 3.4, 5% to 10% of the total coating solution was sufficient to fully coat and color 100 g of seeds (chickpeas or green peas).
[0052] The entire coating solution results in the formation of a thick coating shell, which adheres very well to the seeds and forms a stable film that dries very well.
[0053] In these embodiments, a 1:10 diluted solution of gelatin / collagen hydrolysate (but with the same pigment content) can also be used to fully coat and color 100 g of seeds under the same process parameters, although the time required is significantly longer.
[0054] Example 4: Seed coating using other ingredients
[0055] In these embodiments, a hydrophilic component (ethanol) or a hydrophobic component (medium-chain triglycerides, MCT) was added to the coating solution. These serve as model substances or as possible matrices / carriers for the corresponding active ingredients that can be used in seed coating. The compositions are shown in Table 6: Table 6
[0056] The coating process in the rotary drum coating machine is as described in Example 2. In these examples, despite the addition of ethanol or MCT, 100 g of seeds (chickpeas or green peas) can still be fully coated and colored with 5% to 10% of the total coating solution. The total coating solution results in the formation of a thick coating that adheres very well to the seeds and forms a stable film that dries well.
[0057] In Example 4.2, it was also found that the addition of MCT can reduce the stickiness of the coating, and therefore this addition can also be advantageously used to reduce the risk of individual coated seed particles sticking together.
[0058] Example 5: Adding a crosslinking agent
[0059] The coating solution according to the above embodiments may additionally contain a cross-linking agent in order to extend the degradation time of the coating after sowing by cross-linking the gelatin.
[0060] As a crosslinking agent, for example, tannin powder (0.1% to 2% by weight), olive leaf extract (0.1% to 15% by weight), glyoxal (1,000 ppm) or glutaraldehyde (100 ppm) can be used, each amount based on the total amount of the coating solution.
Claims
1. A seed coating method, the method comprising the following steps: An aqueous coating solution is provided, comprising a Bloom value of about 150 g or less and a Pa2+ of about 2.5 mPa. Gelatin with a viscosity of s or lower, wherein the viscosity is obtained by measuring a 6.67% gelatin solution at 60°C; as well as The coating solution is applied to the seed surface and dried to obtain a gelatin-based coating on the seed.
2. The method according to claim 1, wherein the coating solution is sprayed onto the seed surface, particularly in a rotary drum coating machine, spin coater, coating pan, or fluidized bed dryer.
3. The method according to any one of the preceding claims, wherein the coating solution is applied to the seed surface at a temperature of about 50°C or higher, preferably about 55°C or higher.
4. The method according to any one of the preceding claims, wherein the coating solution is applied and dried at a temperature of about 30°C to about 60°C.
5. The method according to any one of the preceding claims, wherein the coating solution is applied to the seed surface in an amount of about 50 g to about 1,000 g per kilogram of seeds.
6. The method according to any one of the preceding claims, wherein the gelatin has a Bloom value of about 125 g or less, preferably about 100 g or less.
7. The method according to any one of the preceding claims, wherein the gelatin has a strength of about 2.3 mPa. s or lower, preferably about 2.1 mPa The viscosity is s or lower, which is obtained by measuring a 6.67% gelatin solution at 60°C.
8. The method according to any one of the preceding claims, wherein the gelatin is produced from collagen-containing starting materials of mammalian skin or bone, particularly from pigskin.
9. The method according to any one of the preceding claims, wherein the gelatin is type A gelatin digested with acid, type B gelatin digested with alkali, or a mixture thereof.
10. The method according to any one of the preceding claims, wherein the gelatin has a weight-average molecular weight of about 20 kDa to about 100 kDa, preferably about 39 kDa to about 84 kDa.
11. The method according to any one of the preceding claims, wherein the coating solution further comprises one or more protein hydrolysates, wherein the protein hydrolysates are preferably selected from collagen hydrolysates, plant protein hydrolysates, and mixtures thereof.
12. The method of claim 11, wherein the collagen hydrolysate has a weight-average molecular weight of about 0.5 kDa to about 18 kDa, preferably about 2 kDa to about 5 kDa, more preferably about 2.5 kDa to about 3.5 kDa.
13. The method according to any one of the preceding claims, wherein the coating solution comprises gelatin in a proportion of at least about 10% by weight relative to the total weight of the gelatin and the protein hydrolysate, and optionally the protein hydrolysate with a molecular weight up to 18 kDa.
14. The method according to any one of the preceding claims, wherein the coating solution comprises gelatin in a proportion of at least about 40% by weight relative to the total weight of the gelatin and the protein hydrolysate, and optionally the protein hydrolysate with a molecular weight up to 39 kDa.
15. The method according to any one of the preceding claims, wherein the coating solution comprises a total of about 5% to about 30% by weight, preferably about 8% to about 20% by weight, of gelatin and optionally protein hydrolysate.
16. The method according to any one of the preceding claims, wherein the coating solution further comprises one or more crosslinking agents for gelatin, the crosslinking agents preferably selected from tannins, polyphenols and aldehydes, such as glyoxal, glutaraldehyde and formaldehyde.
17. The method according to any one of the preceding claims, wherein the coating solution further comprises one or more plasticizers, the plasticizers preferably selected from sugar alcohols and sugars, particularly selected from glycerol, sorbitol, sorbitan, mannitol, maltitol, xylitol, glucose and sucrose, or selected from propylene glycol, polypropylene glycol and polyethylene glycol.
18. The method according to any one of the preceding claims, wherein the coating solution further comprises one or more active ingredients, the active ingredients preferably selected from plant nutrients, growth promoters and crop protectants, such as insecticides and fungicides.
19. The method according to any one of the preceding claims, wherein the coating solution further comprises one or more additives and / or fillers selected from pigments, such as titanium dioxide and iron oxide; minerals, such as bentonite and kaolin; biodegradable fibers, such as cellulose and keratin; polysaccharides, such as starch and chitosan; or mixtures thereof.
20. The method according to any one of the preceding claims, wherein the seed is selected from cereal seeds, such as wheat, rye, barley, oats, corn, rice and millet; selected from legume seeds, such as kidney beans, peas, lentils, soybeans, chickpeas, sweet peas and lupins; selected from pseudocereal seeds, such as buckwheat, quinoa and amaranth; or selected from oilseeds, such as rapeseed, flax and sunflower.
21. The use of an aqueous coating solution for coating seeds, wherein the coating solution comprises a Bloom value of about 150 g or less and a Pa2+ of about 2.5 mPa. Gelatin with a viscosity of s or lower, wherein the viscosity is obtained by measuring a 6.67% gelatin solution at 60°C.
22. A seed having a gelatin-based coating, wherein the seed is produced by the method according to any one of claims 1 to 20.