Bagging-free fruit cracking prevention film agent for fruits as well as preparation method and use method of bagging-free fruit cracking prevention film agent

Abstract

The invention discloses a bagging-free fruit cracking prevention film agent for fruits as well as a preparation method and a use method of the bagging-free fruit cracking prevention film agent. The bagging-free fruit cracking prevention film agent comprises 1-10 parts of a film forming substrate, 0.3-3 parts of a fruit cracking prevention agent, 0.1-0.6 part of a surfactant, 0.2-2 parts of an antibacterial agent, 0.1-1 part of an auxiliary agent and 84-98 parts of deionized water, the anti-cracking agent is calcium-containing organic nanoparticles. The bagging-free fruit cracking prevention film agent for the fruits comprises a film forming substrate, a fruit cracking prevention agent, a surfactant, an antibacterial agent and an auxiliary agent, the anti-cracking agent is calcium-containing organic nanoparticles and can enter pericarp cells of fruits after being sprayed, the cell wall structure is strengthened, and the anti-cracking effect is achieved; the biostimulant can promote accumulation of fruit sugar degree and flavor substances; a film layer formed after spraying is uniform and flexible, and can be expanded and stretched along with fruits without being broken; the additive can improve the storage layering resistance of the film agent, and the antibacterial agent can enable the film agent to be stored for 6 months at normal temperature and to be free of mildew after being stored for 3 months at 40 DEG C; the film agent is sprayed in a single agent mode, the situation that multiple agent intervals need to be controlled in the prior art is avoided, and the operation efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of fruit cultivation technology, and particularly relates to a fruit-crack-preventing film agent for fruit that does not require bagging, as well as its preparation method and application method. Background Technology

[0002] Grapes are a widely cultivated economic fruit globally, and their yield and quality directly impact agricultural economic benefits. Fruit protection is a core aspect of grape production. Traditionally, plastic bags are used to protect the fruit. While this can, to some extent, isolate pests and diseases, reduce mechanical damage, and improve the fruit's appearance and color, it suffers from high labor costs, complex operations, and environmental pollution, failing to meet the demands of green agriculture development.

[0003] The existing Chinese patent with publication number CN112980253A discloses a humic acid-based fruit bag-free film agent. When spraying, the application interval between agent A and agent B needs to be strictly controlled, otherwise it will affect the film-forming effect, making the actual operation difficult. Moreover, the film agent contains sodium alginate, which is prone to mold growth during storage, has poor stability, and a short storage period. Summary of the Invention

[0004] The purpose of this invention is to provide a fruit-crack-preventing film agent for fruit without bagging, as well as its preparation and application methods, in order to solve the technical problems of high difficulty in actual spraying of the fruit-crack-preventing film agent and poor stability of the film agent, which makes it difficult to store for a long time.

[0005] To solve the above-mentioned technical problems, the present invention is mainly achieved through the following technical solutions: In a first aspect, the present invention provides a fruit-crack-preventing film agent for fruit without bagging, comprising the following components by weight: 1-10 parts of film-forming matrix, 0.3-3 parts of anti-crack agent, 0.1-0.6 parts of surfactant, 0.2-2 parts of antibacterial agent, 0.1-1 parts of adjuvant, and 84-98 parts of deionized water; wherein the anti-crack agent is calcium-containing organic nanoparticles.

[0006] In some embodiments of this application, the film-forming matrix is ​​selected from one or more combinations of polyacrylic acid, polyethylene oxide, polyvinyl alcohol, polymaleic anhydride, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, sodium carboxymethyl cellulose, hydroxypropyl methylcellulose, methylcellulose, soluble starch, low-methoxyl pectin, polyvinyl acetate, or gelatin.

[0007] In some embodiments of this application, the anti-cracking agent includes calcium-based anti-cracking components, biostimulants, and nutrient-enhancing components.

[0008] In some embodiments of this application, the surfactant is selected from one or more combinations of Tween 80, alkyl glycosides, imidazoline amphoteric surfactants, dodecyl dimethyl betaine, and isomeric alcohol ethers.

[0009] In some embodiments of this application, the antibacterial agent is selected from one or more combinations of chitosan, sodium benzoate, potassium sorbate, and hesperidin.

[0010] In some embodiments of this application, the additive is selected from one of vinylpyrrolidone-ethyl acetate block copolymer with 30% VA content, glycerol, or 25% glutaraldehyde aqueous solution.

[0011] In some embodiments of this application, the particle size of the calcium-containing organic nanoparticles is 5~20 nm.

[0012] In a second aspect, the present invention provides a method for preparing a fruit-crack-resistant film agent for fruit without bagging, as described in any one of the embodiments of the first aspect above, comprising the following steps: S1: Weigh the film-forming matrix and deionized water according to the ratio, add them to the container and mix, stirring until completely dissolved; let stand and cool to room temperature to obtain the basic solution; S2: Dissolve the biostimulant in deionized water to prepare solution A with a mass fraction of 0.1-5%; dissolve the nutrient-enhancing ingredient in deionized water to prepare solution B with a mass fraction of 0.1-5%; dissolve the calcium-based anti-cracking ingredient in deionized water to prepare solution C with a mass fraction of 5%; under stirring conditions, mix solution A and solution B at a mass ratio of 0.5-5:1 to obtain mixed solution one; then slowly add solution C to mixed solution one, stir continuously for 15 minutes, and let stand to obtain a calcium-containing organic nanoparticle suspension; S3: Under stirring conditions, add the calcium-containing organic nanoparticle suspension and antibacterial agent prepared in S2 to the base solution prepared in S1 according to the ratio until the solid is completely dissolved, let it stand to defoam, and obtain mixed solution two. S4: Add surfactant dropwise to the mixed solution 2 obtained in S3 according to the ratio, and then add the auxiliary agent. Mix the components evenly under stirring conditions to obtain a fruit-crack-preventing film agent for fruit without bagging.

[0013] In some embodiments of this application, in S1, the temperature is controlled at 25~95℃ and the stirring rate is 100~800rpm.

[0014] In a third aspect, the present invention provides a method for using a fruit-crack-preventing film agent for fruit without bagging, as described in the first aspect embodiment above. The agent is sprayed during the secondary expansion period of the fruit, and the surface of the fruit is completely wetted until it begins to drip naturally, ensuring that the fruit is evenly covered.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: The fruit-crack-preventing film agent for fruit that eliminates the need for bagging, disclosed in this invention, comprises a film-forming matrix, an anti-cracking agent, a surfactant, an antibacterial agent, and adjuvants. All raw materials are inexpensive agricultural or food-grade materials, easily affordable for ordinary growers. The anti-cracking agent consists of calcium-containing organic nanoparticles, which, after spraying, penetrate the fruit peel cells, strengthening the cell wall structure and preventing cracking. It also contains biostimulants, which promote the accumulation of sugar and flavor compounds in the fruit. The film layer formed after spraying is uniform and flexible, and can stretch with the fruit's growth without breaking. The adjuvants enhance the film's flexibility, stability, and resistance to stratification during storage. The addition of an antibacterial agent ensures the film agent remains mold-free after 6 months of storage at room temperature and 3 months at 40°C. This application's film agent is a single-agent spray, avoiding the need for controlling multiple agent intervals in existing technologies, thus improving operational efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 Scanning electron microscope image of the anti-cracking agent prepared in Example 1 of this invention; Figure 2 The fruit cracking rate of Sunshine Rose fruit after spraying with the bag-free anti-cracking film agent for fruit prepared in Example 2 of the present invention; Figure 3 Storage stability test chart of the fruit-free anti-crack film agent for fruits prepared in Example 3 of the present invention; Figure 4 The images show the state of the bag-free anti-crack fruit film agent for fruit before and after spraying onto Sunshine Rose fruit, as provided in Example 4 of this invention. Figure 5 The image shows the state of the fruit-crack-resistant film agent for fruit prepared in Example 4 of this invention after curing. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the 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.

[0019] The fruit-crack-resistant film agent for fruit that does not require bagging provided in this embodiment is applicable to various fruits including but not limited to grapes, pomegranates, etc. The following description uses Shine Muscat grapes as an example.

[0020] In a first aspect, embodiments of this disclosure provide a fruit-crack-preventing film agent for fruit that does not require bagging, comprising the following components by weight: 1-10 parts of film-forming matrix, 0.3-3 parts of anti-crack agent, 0.1-0.6 parts of surfactant, 0.2-2 parts of antibacterial agent, 0.1-1 parts of adjuvant, and 84-98 parts of deionized water; wherein the anti-crack agent is calcium-containing organic nanoparticles with a particle size of 5-20 nm.

[0021] Specifically, the fruit-bagged, anti-cracking film agent for fruits includes a film-forming matrix, an anti-cracking agent, a surfactant, an antibacterial agent, and adjuvants. All raw materials are inexpensive agricultural or food-grade materials, easily affordable for ordinary growers. The anti-cracking agent consists of calcium-containing organic nanoparticles that provide nutrients to the fruit peel, preventing cracking. The addition of an antibacterial agent ensures the film agent remains mold-free and does not delaminate even after 6 months of storage at room temperature or 3 months at 40℃. The film formed after spraying is uniform and flexible, with a breaking elongation of over 250%, allowing it to stretch as the fruit expands without breaking, and does not affect fruit coloring or sugar accumulation. Furthermore, the film agent is a single-agent spray, avoiding the need for multiple agent intervals required in existing technologies, thus improving operational efficiency.

[0022] In some embodiments of this application, the film-forming matrix is ​​selected from one or more combinations of polyacrylic acid, polyethylene oxide, polyvinyl alcohol, polymaleic anhydride, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, sodium carboxymethyl cellulose, hydroxypropyl methylcellulose, methylcellulose, soluble starch, low-methoxyl pectin, polyvinyl acetate, or gelatin.

[0023] Specifically, the film-forming matrix forms a continuous film through intermolecular hydrogen bonds. The aforementioned film-forming matrix materials are widely available, have good film-forming properties, and combine transparency and air permeability, without affecting the photosynthesis and sugar accumulation of grapes.

[0024] In some embodiments of this application, the anti-cracking agent comprises nanoparticles composed of calcium-based anti-cracking components, biostimulants, and nutrient-enhancing components.

[0025] Specifically, anti-cracking agents include calcium-based anti-cracking components, biostimulants, and nutrient enhancers, enabling the film to have both anti-cracking and growth-promoting functions.

[0026] In some embodiments of this application, the calcium-based anti-cracking component is selected from one or more combinations of calcium lignosulfonate, calcium chloride, calcium sulfate, calcium lactate, calcium citrate, calcium nitrate, or calcium gluconate.

[0027] Specifically, the calcium-based anti-cracking ingredient focuses on calcium supplementation. The nano-sized calcium-based anti-cracking ingredient can efficiently enter the fruit cells through the stomata on the surface of the peel via endocytosis, strengthen the cell wall structure, and combine with the cell wall pectin to form "calcium bridge" calcium pectate, which significantly enhances the stability of the cell wall structure; it also enhances the adhesion between grape peel cells, strengthens the cell wall from the inside, reduces the brittleness of the peel, and fundamentally prevents fruit cracking.

[0028] In some embodiments of this application, the nutrient-enhancing ingredients are selected from one or more combinations of silica sol, boric acid, sodium tetraborate, zinc sulfate, sodium lignosulfonate, zinc gluconate, zinc lactate, zinc citrate, hydroxyethyl methylcellulose, sodium carboxymethyl cellulose, hydroxypropyl cellulose, and methylcellulose.

[0029] Specifically, the nutrient-enhancing components can work synergistically with the calcium-based anti-cracking components to achieve targeted nutrient supply; boron can protect flowers and fruits and prevent grain size; zinc can promote growth and prevent grain size; organosilicon has health-preserving and stress-resistant effects; elements such as zinc and boron can regulate osmotic pressure and metabolic balance, stabilize the nanoparticle structure, prevent aggregation, and extend the efficacy period.

[0030] In some embodiments of this application, the biostimulant is selected from one or more combinations of seaweed polysaccharides, betaine, humic acid, fulvic acid, polyaspartic acid, polyγ-glutamic acid, brassinolide, chitosan, and chitosan oligosaccharides.

[0031] Specifically, biostimulants can regulate cell metabolism, reduce turgor pressure imbalance caused by rapid water absorption, and work with boron and zinc to promote pectin synthesis and regulate the osmotic pressure inside and outside the fruit. They also work synergistically with calcium-based anti-cracking components to achieve an anti-cracking rate of ≥96%.

[0032] Specifically, amino acids can improve the utilization rate of water and nutrients, thereby indirectly promoting growth; chitosan and chitosan oligosaccharides can promote fruit coloring and increase sugar content; and achieve targeted regulation of nutrient transport and absorption, thus promoting fruit growth and development.

[0033] Biostimulants mediate the transport and absorption of nutrients such as calcium, boron, and zinc, preventing nutrient loss; they also have water-retention and slow-release nutrient functions, continuously supporting fruit growth and increasing soluble solids content.

[0034] In some embodiments of this application, the surfactant is selected from one or more combinations of Tween 80, alkyl glycosides, imidazoline amphoteric surfactants, dodecyl dimethyl betaine, and isomeric alcohol ethers.

[0035] Specifically, surfactants can reduce the contact angle between the film agent and the fruit peel, which is beneficial for the film agent to be evenly dispersed on the surface of the fruit peel.

[0036] In some embodiments of this application, the antibacterial agent is selected from one or more combinations of chitosan, sodium benzoate, potassium sorbate, and hesperidin.

[0037] Specifically, antibacterial agents bind to the charge of pathogen cell membranes through electrical charge, thereby disrupting the integrity and stability of the cell membranes and extending shelf life. All antibacterial agents are selected from food-grade products and will not cause harm to consumers.

[0038] In some embodiments of this application, the additives are selected from vinylpyrrolidone-ethyl acetate block copolymer with a VA content of 30%, glycerol, or an aqueous solution of glutaraldehyde with a mass fraction of 25%.

[0039] Specifically, the additives enhance the flexibility of the film through plasticizing, allowing the film layer to stretch as the fruit expands, preventing the film from rupturing due to fruit expansion. They also improve the film's resistance to delamination during storage and enhance its stability.

[0040] In a second aspect, embodiments of this disclosure provide a method for preparing a bag-free, crack-resistant fruit film agent for fruits as described in any of the embodiments of the first aspect above, comprising the following steps: S1: Dissolution and defoaming of the film-forming matrix: Weigh the film-forming matrix and deionized water according to the ratio, add them to an oil bath or water bath equipped with a stirrer, control the reaction temperature at 25~95℃, the stirring rate at 100~800rpm, stir for 15~300min until the film-forming matrix is ​​completely dissolved; stop stirring, let stand and cool to room temperature to obtain the base solution.

[0041] In some embodiments of this application, the reaction temperature is controlled to be 40~85°C.

[0042] For example, the reaction temperature is 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, or 85°C.

[0043] Specifically, heating and stirring can increase the dissolution rate. When the stirring rate is too low, the film-forming matrix may not dissolve completely, while when the stirring rate is too high, too many air bubbles may be introduced.

[0044] In some other embodiments of this application, the stirring rate is controlled to be 300~600 rpm.

[0045] For example, the stirring speed is 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, or 600 rpm.

[0046] In some other embodiments of this application, the stirring time is 30 to 120 minutes.

[0047] S2: Synthesis of anti-cracking agent: Dissolve the biostimulant in deionized water to prepare solution A with a mass fraction of 0.1-5%; dissolve the nutrient-enhancing component in deionized water to prepare solution B with a mass fraction of 0.1-5%; dissolve the calcium-based anti-cracking component in deionized water to prepare solution C with a mass fraction of 5%; mix solutions A and B at a mass ratio of 0.5-5:1 under room temperature and stirring conditions to obtain mixed solution one; slowly add solution C to mixed solution one, stir continuously for 15 minutes, and then let stand to obtain a calcium-containing organic nanoparticle suspension.

[0048] Specifically, the mass ratio of mixed solution one to solution C is 0.5~7:1, which is beneficial for precise control of nanoparticle size and avoids agglomeration.

[0049] Specifically, when the mass fraction of the calcium-based anti-cracking component in solution C is too high, calcium hydroxide precipitate will form. This precipitation process will disrupt the stability of the nanospheres mediated by electrostatic interactions, thereby causing the nanospheres to dissociate.

[0050] S3: Add the calcium-containing organic nanoparticle suspension and antibacterial agent prepared in S2 to the base solution prepared in S1 according to the ratio. Keep the temperature at room temperature, control the stirring speed at 100~800rpm, stir for 20~80min until the solid is completely dissolved, let it stand at room temperature for 0.5h to defoam, and obtain mixed solution two.

[0051] S4: Add surfactant to the mixed solution 2 prepared in S3 at a dropping rate of 0.5~5mL / min according to the ratio, then add auxiliary agent, control the stirring speed at 100~800rpm, stir for 5~60min until all components are mixed evenly, so as to obtain a uniform and transparent fruit-proof film agent for fruit without bagging.

[0052] Specifically, the calcium-containing organic nanoparticles in the fruit-free, anti-crack fruit film agent prepared using the above method remain in a stable dispersion state.

[0053] In a third aspect, the present disclosure provides a method for using a bag-free anti-cracking film agent for grapes as described in the first aspect embodiment above, including spraying during the secondary expansion period of grape fruit, spraying until the surface of the grape fruit is completely wetted until it begins to drip naturally, ensuring that the grape fruit is evenly covered; Spraying operation parameters: Use an agricultural sprayer, control the spraying pressure to 0.2~0.3MPa, and the spraying amount to 5~30mL / ㎡ of orchard; when spraying, control the distance between the nozzle and the fruit to 5~40cm, and spray at a 45° angle to ensure uniform adhesion of the film agent; Applicable environmental conditions: The suitable spraying temperature is 5~35℃, and the relative humidity is ≤85%; avoid spraying in high temperature, strong light or windy weather to prevent the film agent from drying too quickly and causing uneven film formation.

[0054] The raw materials used in the following examples are all commercially available agricultural or food-grade products: Polyvinyl alcohol (PVA 1750): Sinopharm Chemical Reagent Co., Ltd.; Polyacrylic acid (PAA, degree of polymerization 1000-1500): Sinopharm Chemical Reagent Co., Ltd.; Polyethylene oxide (PEO, degree of polymerization 2000-5000): Sinopharm Chemical Reagent Co., Ltd.; Polyethylene glycol (PEG, molecular weight 4000): Sinopharm Chemical Reagent Co., Ltd.; Polyacrylamide (PAM, degree of polymerization 500,000-1,500,000): Sinopharm Chemical Reagent Co., Ltd. Sodium carboxymethyl cellulose (CMC-Na, degree of substitution 0.7): Sinopharm Chemical Reagent Co., Ltd. Chitosan (90% deacetylation): Shandong Aokang Biotechnology Co., Ltd. Polyaspartic acid (PASP, degree of polymerization 20-60): Sinopharm Chemical Reagent Co., Ltd. Poly-γ-glutamic acid (γ-PGA): Sinopharm Chemical Reagent Co., Ltd.; Hydroxyethyl methylcellulose (HEMC, 10,000 mPa·s) Sodium carboxymethyl cellulose (CMC-Na, 800-1200 mPa·s) Hydroxypropyl cellulose (HPC, 4000 mPa·s) Methylcellulose (MC, 4000 mPa·s) Silica sol (particle size 10~20nm): Qingdao Ocean Chemical Co., Ltd.; All other raw materials are commercially available products, and their purity meets agricultural application standards.

[0055] Example 1: The fruit-crack-preventing film agent for fruit without bagging, by weight, includes 2 parts polyvinyl alcohol, 4 parts polyethylene oxide, 1 part calcium-containing organic nanoparticles (0.3 parts calcium sulfate + 0.2 parts polyaspartic acid + 0.1 parts boric acid + 0.1 parts hydroxypropyl cellulose, particle size 8~12nm), 0.1 parts Tween 80, 1.2 parts chitosan, 0.2 parts glycerol, and 91.5 parts deionized water.

[0056] The preparation steps are as follows: 1. Dissolving the film-forming matrix: Add 2g of polyvinyl alcohol and 4g of polyethylene oxide to 91.5g of deionized water, place in a stirrable water bath at 65℃ and 400rpm, and stir for 60min until completely dissolved; cool to 25℃ to obtain the basic solution; 2. Synthesis of calcium-containing organic nanoparticles: 0.2g of polyaspartic acid was dissolved in deionized water to prepare solution A (mass fraction 0.5%), 0.1g of boric acid and 0.1g of hydroxypropyl cellulose were mixed and dissolved in deionized water to prepare solution B (mass fraction 0.5%), and 0.3g of calcium sulfate was dissolved in deionized water to prepare solution C (mass fraction 5%). Solution A and solution B were first mixed evenly in a mass ratio of 3:2 to obtain mixed solution one. Then, solution C was slowly added to mixed solution one, with a mass ratio of mixed solution one to solution C of 3:1. After stirring continuously for 15 minutes, the mixture was allowed to stand to obtain a suspension of calcium-containing organic nanoparticles with a particle size of 8~12nm. 3. Add the above calcium-containing organic nanoparticle suspension and 1.2g chitosan to the base solution in sequence, stir at 400rpm for 25min until completely dissolved; let stand for 30min to remove bubbles, and obtain mixed solution two.

[0057] 4. Add 0.1g Tween 80 and 0.2g glycerol to mixed solution 2 at a dropping rate of 2mL / min, stir at 600rpm for 20min, let stand to remove bubbles, and obtain a transparent fruit-crack-preventing film agent for fruit without bagging.

[0058] At an ambient temperature of 26℃ and a relative humidity of 65%, the above-prepared fruit-protecting film agent for fruit without bagging was sprayed onto Shine Muscat grapes using a conventional agricultural sprayer. The spraying time was selected during the secondary fruit expansion period of Shine Muscat grapes. The spraying pressure was controlled at 0.3MPa, and the spraying amount was 25mL / ㎡ of orchard. During spraying, the nozzle was kept 20cm away from the fruit and sprayed at a 45° angle to ensure that the fruit was evenly covered by the film agent. The spraying continued until the fruit surface was completely wetted and began to drip water naturally.

[0059] Example 2: The fruit-crack-preventing film agent for fruit without bagging, by weight, includes 4 parts polyvinyl alcohol, 1.3 parts calcium-containing organic nanoparticles (0.5 parts calcium citrate + 0.2 parts polyγ-glutamic acid + 0.2 parts sodium tetraborate + 0.1 parts silica sol + 0.1 parts methylcellulose, particle size 10~15nm), 0.2 parts alkyl glycoside, 0.1 parts sodium benzoate, 0.1 parts potassium sorbate, 0.1 parts vinylpyrrolidone-ethyl acetate block copolymer (PVP-VA), and 94.2 parts deionized water.

[0060] The preparation steps are as follows: 1. Dissolving the film-forming matrix: Add 4g of polyvinyl alcohol to 94.2g of deionized water, stir at 95℃ and 400rpm for 60min until dissolved; cool to 25℃ to obtain the basic solution; 2. Synthesis of calcium-containing organic nanoparticles: 0.2g of polyγ-glutamic acid was dissolved in deionized water to prepare solution A (1% by mass). 0.2g of sodium tetraborate, 0.1g of silica sol, and 0.1g of methylcellulose were mixed and dissolved in deionized water to prepare solution B (0.5% by mass). 0.5g of calcium citrate was dissolved in deionized water to prepare solution C (5% by mass). Solution A and solution B were first mixed evenly in a mass ratio of 2.5:1 to obtain mixed solution one. Then, solution C was slowly added to mixed solution one in a mass ratio of 1.5:1. After stirring continuously for 15 minutes, the mixture was allowed to stand to obtain a suspension of calcium-containing organic nanoparticles with a particle size of 10-15nm. 3. Add the above calcium-containing organic nanoparticle suspension, 0.1g sodium benzoate, and 0.1g potassium sorbate to the base solution in sequence, stir at 400rpm for 30min until dissolved; let stand to remove bubbles, and obtain mixed solution two; 4. Add 0.2g alkyl glycoside and 0.1g PVP-VA to mixed solution II at a dropping rate of 2mL / min, stir at 600rpm for 20min; let stand to remove bubbles, and obtain a fruit-crack-preventing film agent for fruit without bagging.

[0061] At an ambient temperature of 26℃ and a relative humidity of 65%, the above-prepared fruit-protecting film agent for fruit without bagging was sprayed onto Shine Muscat grapes using a conventional agricultural sprayer. The spraying time was selected during the secondary fruit expansion period of Shine Muscat grapes. The spraying pressure was controlled at 0.3MPa, and the spraying amount was 25mL / ㎡ of orchard. During spraying, the nozzle was kept 20cm away from the fruit and sprayed at a 45° angle to ensure that the fruit was evenly covered by the film agent. The spraying continued until the fruit surface was completely wetted and began to drip water naturally.

[0062] Example 3: The fruit-crack-preventing film agent for fruit without bagging, by weight, includes 4 parts hydroxypropyl methylcellulose, 3 parts polyvinylpyrrolidone (PVP), 1.6 parts calcium-containing organic nanoparticles (0.7 parts calcium lignosulfonate + 0.2 parts polyaspartic acid + 0.1 parts zinc sulfate + 0.1 parts hydroxypropyl cellulose + 0.3 parts sodium lignosulfonate, particle size 7~13nm), 0.1 parts imidazoline, 0.8 parts hesperidin, 0.2 parts glycerol, and 90.3 parts deionized water.

[0063] The preparation steps are as follows: 1. Dissolving the film-forming matrix: Add 4g of hydroxypropyl methylcellulose and 3g of polyvinylpyrrolidone to 90.3g of deionized water, stir at 50℃ and 400rpm for 30min until dissolved; cool to 25℃, let stand to remove bubbles, and obtain the basic solution; 2. Synthesis of calcium-containing organic nanoparticles: 0.2g of polyaspartic acid was dissolved in deionized water to prepare solution A (2.5% by mass). 0.1g of zinc sulfate, 0.1g of hydroxypropyl cellulose, and 0.1g of sodium lignosulfonate were mixed and dissolved in deionized water to prepare solution B (1.2% by mass). 0.7g of calcium lignosulfonate was dissolved in deionized water to prepare solution C (5% by mass). Solution A and solution B were first mixed evenly in a mass ratio of 2:1 to obtain mixed solution one. Then, solution C was slowly added to mixed solution one, with a mass ratio of mixed solution one to C of 3:2. After stirring continuously for 15 minutes, the mixture was allowed to stand to obtain a suspension of calcium-containing organic nanoparticles with a particle size of 7-13nm. 3. Add calcium-containing organic nanoparticle suspension and 0.8g hesperidin to the base solution in sequence, stir at 400rpm for 30min until dissolved; let stand to remove bubbles, and obtain mixed solution two.

[0064] 4. Add 0.1g imidazoline and 0.2g glycerol dropwise to mixed solution II at 2mL / min, stir at 600rpm for 20min; let stand to remove bubbles, and obtain a fruit-crack-preventing film agent for fruit without bagging.

[0065] At an ambient temperature of 26℃ and a relative humidity of 65%, the above-prepared fruit-protecting film agent for fruit without bagging was sprayed onto Shine Muscat grapes using a conventional agricultural sprayer. The spraying time was selected during the secondary fruit expansion period of Shine Muscat grapes. The spraying pressure was controlled at 0.3MPa, and the spraying amount was 25mL / ㎡ of orchard. During spraying, the nozzle was kept 20cm away from the fruit and sprayed at a 45° angle to ensure that the fruit was evenly covered by the film agent. The spraying continued until the fruit surface was completely wetted and began to drip water naturally.

[0066] Example 4: The fruit-crack-preventing film agent for fruit without bagging, by weight, includes 2.6 parts of low-methoxyl pectin, 6 parts of gelatin, 2.5 parts of calcium-containing organic nanoparticles (1.7 parts of calcium citrate + 0.3 parts of polyγ-glutamic acid + 0.2 parts of boric acid + 0.1 parts of sodium carboxymethyl cellulose + 0.3 parts of zinc sulfate + 0.2 parts of silica sol, particle size 9~16nm), 0.5 parts of chitosan, 0.1 parts of glutaraldehyde, 0.1 parts of Tween 80, and 88.2 parts of deionized water.

[0067] The preparation steps are as follows: 1. Dissolving the film-forming matrix: Add 2.6g of low-methoxyl pectin and 6g of gelatin to 88.2g of deionized water, stir at 25℃ and 400rpm for 45min until dissolved; let stand to remove bubbles, and obtain the basic solution; 2. Synthesis of calcium-containing organic nanoparticles: 0.3g of polyγ-glutamic acid was dissolved in deionized water to prepare solution A (mass fraction 1.5%). 0.3g of zinc sulfate, 0.1g of sodium carboxymethyl cellulose, 0.2g of boric acid, and 0.2g of silica sol were mixed and dissolved in deionized water to prepare solution B (mass fraction 0.8%). 1.7g of calcium citrate was dissolved in deionized water to prepare solution C (mass fraction 5%). Solution A and solution B were first mixed evenly in a mass ratio of 4:3 to obtain mixed solution one. Then, solution C was slowly added to mixed solution one in a mass ratio of 2:1. After stirring continuously for 15 minutes, the mixture was allowed to stand to obtain a suspension of calcium-containing organic nanoparticles with a particle size of 9-16nm. 3. Add the above calcium-containing organic nanoparticle suspension and 0.5g chitosan to the base solution in sequence, stir at 400rpm for 30min until dissolved; let stand to remove bubbles, and obtain mixed solution two; 4. Add 0.1g Tween 80 and 0.1g glutaraldehyde to mixed solution 2, stir at 40℃ and 600rpm for 20min; let stand to remove bubbles, cool to 25℃, and obtain a fruit-crack-preventing film agent for fruit without bagging.

[0068] At an ambient temperature of 26℃ and a relative humidity of 65%, the above-prepared fruit-protecting film agent for fruit without bagging was sprayed onto Shine Muscat grapes using a conventional agricultural sprayer. The spraying time was selected during the secondary fruit expansion period of Shine Muscat grapes. The spraying pressure was controlled at 0.3MPa, and the spraying amount was 25mL / ㎡ of orchard. During spraying, the nozzle was kept 20cm away from the fruit and sprayed at a 45° angle to ensure that the fruit was evenly covered by the film agent. The spraying continued until the fruit surface was completely wetted and began to drip water naturally.

[0069] The states of Sunshine Rose before and after spraying in Example 4 are as follows: Figure 4 and Figure 5 As shown, where, Figure 5 The circled area represents the state of the cured film layer after being peeled from the Sun Rose plant. The film layer has an elongation at break of over 250% and good flexibility.

[0070] Example 5: A fruit-crack-preventing film agent for fruit without bagging, by weight, comprises 6 parts polyethylene glycol, 2 parts polyvinylpyrrolidone, 2 parts sodium carboxymethyl cellulose, 2 parts calcium-containing organic nanoparticles (0.9 parts calcium nitrate + 0.2 parts polyaspartic acid + 0.1 parts silica sol + 0.1 parts methyl cellulose, particle size 6~11 nm), 0.2 parts alkyl glycoside, 0.4 parts potassium sorbate, 0.1 parts glycerol, and 87.3 parts deionized water.

[0071] The preparation steps are as follows: 1. Dissolving the film-forming matrix: Add 6g of polyethylene glycol, 2g of polyvinylpyrrolidone, and 2g of sodium carboxymethyl cellulose to 97.3g of deionized water, place in a water bath at 75℃ and 400rpm, and stir for 40min until dissolved; cool to 25℃, let stand to remove bubbles, and obtain the basic solution; 2. Synthesis of calcium-containing organic nanoparticles: 0.2g of polyaspartic acid was dissolved in deionized water to prepare solution A (3% by mass), 0.1g of methylcellulose and 0.1g of silica sol were mixed and dissolved in deionized water to prepare solution B (1.6% by mass), and 0.9g of calcium nitrate was dissolved in deionized water to prepare solution C (5% by mass). Solution A and solution B were first mixed evenly in a mass ratio of 5:2 to obtain mixed solution one. Then, solution C was slowly added to mixed solution one in a mass ratio of 4:3. After stirring continuously for 15 minutes, the mixture was allowed to stand to obtain a suspension of calcium-containing organic nanoparticles with a particle size of 6-11nm. 3. Add the above calcium-containing organic nanoparticle suspension and 0.4g potassium sorbate to the base solution in sequence, stir at 400rpm for 30min until dissolved; let stand to remove bubbles, and obtain mixed solution two; 4. Add 0.2g alkyl glycoside and 0.1g glycerol to mixed solution 2, stir at 600rpm for 20min; let stand to remove bubbles, and obtain the bag-free anti-crack fruit film agent.

[0072] At an ambient temperature of 26℃ and a relative humidity of 65%, the above-prepared fruit-protecting film agent for fruit without bagging was sprayed onto Shine Muscat grapes using a conventional agricultural sprayer. The spraying time was selected during the secondary fruit expansion period of Shine Muscat grapes. The spraying pressure was controlled at 0.3MPa, and the spraying amount was 25mL / ㎡ of orchard. During spraying, the nozzle was kept 20cm away from the fruit and sprayed at a 45° angle to ensure that the fruit was evenly covered by the film agent. The spraying continued until the fruit surface was completely wetted and began to drip water naturally.

[0073] Example 6: The fruit-crack-preventing film agent for fruit without bagging, by weight, includes 8 parts of hydroxypropyl methylcellulose (HPMC), 2.6 parts of calcium-containing organic nanoparticles (1.0 part of calcium citrate + 0.3 parts of polyγ-glutamic acid + 0.2 parts of sodium tetraborate + 0.1 parts of hydroxyethyl methylcellulose, particle size 11~17nm), 0.3 parts of imidazoline, 1 part of hesperidin, 0.3 parts of vinylpyrrolidone-ethyl acetate block copolymer (PVP-VA), and 87.8 parts of deionized water.

[0074] The preparation steps are as follows: 1. Dissolving the film-forming matrix: Add 8g HPMC to 87.8g deionized water, stir at 50℃ and 400rpm for 30min until dissolved; cool to 25℃, let stand to remove bubbles, and obtain the basic solution; 2. Synthesis of calcium-containing organic nanoparticles: 0.3g of polyγ-glutamic acid was dissolved in deionized water to prepare solution A (mass fraction 4.1%), 0.1g of hydroxyethyl methylcellulose and 0.2g of sodium tetraborate were mixed and dissolved in deionized water to prepare solution B (mass fraction 2%), and 1g of calcium citrate was dissolved in deionized water to prepare solution C (mass fraction 5%). Solution A and solution B were first mixed evenly in a mass ratio of 3:2 to obtain mixed solution one. Then, solution C was slowly added to mixed solution one, with a mass ratio of mixed solution one to solution C of 4:1. After stirring continuously for 15 minutes, the mixture was allowed to stand to obtain a suspension of calcium-containing organic nanoparticles with a particle size of 11~17nm. 3. Add the above calcium-containing organic nanoparticle suspension and 1g of hesperidin to the base solution in sequence, stir at 400rpm for 30min until dissolved; let stand to remove bubbles, and obtain mixed solution two; 4. Add 0.3g imidazoline and 0.3g PVP-VA to mixed solution 2, stir at 600rpm for 20min; let stand to remove bubbles, and obtain a transparent fruit-crack-preventing film agent for fruit without bagging.

[0075] At an ambient temperature of 26℃ and a relative humidity of 65%, the above-prepared fruit-protecting film agent for fruit without bagging was sprayed onto Shine Muscat grapes using a conventional agricultural sprayer. The spraying time was selected during the secondary fruit expansion period of Shine Muscat grapes. The spraying pressure was controlled at 0.3MPa, and the spraying amount was 25mL / ㎡ of orchard. During spraying, the nozzle was kept 20cm away from the fruit and sprayed at a 45° angle to ensure that the fruit was evenly covered by the film agent. The spraying continued until the fruit surface was completely wetted and began to drip water naturally.

[0076] Performance testing: Control group 1 (no spraying), control group 2 (traditional bagging).

[0077] 1. Fruit cracking rate test: Select 10 Sunshine Rose grapevines with uniform growth, and select 3 fruiting branches from each vine. After spraying with film agent, count the number of cracked fruits every 7 days until maturity. Fruit cracking rate = number of cracked fruits / total number of fruits × 100%.

[0078] 2. Fruit quality test: The soluble solids content (sugar index) in the fruit was determined using a handheld refractometer. 30 fruits were tested in each group, and the average value was taken.

[0079] 2.1 The cracking rate, fruit quality, and single fruit weight of Shine Muscat grapes from Examples 1-6 and Control Groups 1-2 were tested. The test results are shown in Table 1 below: Table 1 shows the test results of fruit cracking rate, soluble solids content, and single fruit weight of Shine Muscat grapes in Examples 1-6 and Control Groups 1-2.

[0080] As shown in Table 1, after spraying the fruit-free anti-cracking film agent for fruits, the cracking rate of Shine Muscat was about 2.51%, while the cracking rate of Shine Muscat in control group 1 (without spraying) was 21.5%, and the cracking rate of control group 2 (using traditional bagging) was 4.5%. Therefore, it can be seen that the fruit-free anti-cracking film agent for fruits has a highly effective anti-cracking effect.

[0081] As shown in Table 1, after spraying with the fruit-protecting and anti-cracking agent for fruit without bagging, the soluble solids content of Shine Muscat roses was around 19%, while the soluble solids content of the unsprayed Shine Muscat roses in control group 1 was 17.1%, and the soluble solids content of control group 2, which used traditional bagging, was 15.7%. Spraying with the fruit-protecting and anti-cracking agent for fruit without bagging can increase the soluble solids content of Shine Muscat roses and increase glucose content.

[0082] Meanwhile, Table 1 also shows that spraying the fruit-free anti-crack film agent for fruits can increase nutrient supply, make the fruits develop more evenly and plump, accumulate more sugar and flavor substances, increase the weight of individual fruits of Sunshine Rose, and help fruit farmers increase their income.

[0083] 2.2 The anti-cracking agent (containing calcium organic nanoparticles) prepared in Example 1 was characterized, and its scanning electron microscope (SEM) images are shown below. Figure 1 : Depend on Figure 1 As can be seen, the calcium-containing organic nanoparticles show no obvious agglomeration and exhibit a uniform and stable dispersion. Their ultra-small particle size can effectively increase the contact area and penetration efficiency between the particles and the surface of the grape fruit, which is conducive to the efficient absorption of calcium and related nutrients by the grape fruit, thereby meeting the dual needs of preventing fruit cracking and providing nutrition in the context of grape cultivation without bagging.

[0084] 2.3 A test was conducted on the fruit cracking rate and spraying cycle of the Shine Muscat grape variety from Example 2, combined with... Figure 2 As shown, Figure 2 In the diagram, black represents the experimental group of Example 2 (sprayed with film agent), and red represents the corresponding blank control group (no film agent sprayed). The test cycle is once every two days.

[0085] have Figure 2 It can be seen that as the spraying cycle increases, the fruit cracking rate of the experimental group in Example 2 is 2.8%~3.5%, while the fruit cracking rate of the blank control group is as high as 19.8%~22.5%. The fruit cracking rate of the blank control group is much higher than that of the experimental group. Therefore, the fruit cracking prevention film agent for fruit without bagging in this example can significantly reduce the fruit cracking rate.

[0086] 3. Antibacterial rate test: The plate inhibition method was used to determine the inhibition rate of the film on grape downy mildew and gray mold. Antibacterial rate = (number of colonies in the blank group - number of colonies in the treatment group) / number of colonies in the blank group × 100%.

[0087] The antibacterial properties of the films in Examples 1-6 were tested, and the results are shown in Table 2 below: Table 2 shows the inhibition test results of the film-forming agents in Examples 1-6 against downy mildew and gray mold, respectively.

[0088] As can be seen from Table 2, the film preparations prepared in Examples 1-6 all showed an inhibition rate of over 94% against downy mildew and gray mold. On the one hand, the fruit-crack-preventing film preparations for fruit can effectively inhibit downy mildew and gray mold, and can extend the storage time of the film preparations themselves. On the other hand, the film formed by spraying the film preparations onto the surface of grapes can improve the disease resistance of Sunshine Rose grapes, reduce diseases, make the fruit develop more evenly, and accumulate more sugar and flavor substances, thus reducing the number of times and amount of pesticides used.

[0089] 4. Storage stability test: Seal the film agent in a transparent sample bottle and place it in a constant temperature environment of 25℃ and 40℃ respectively. Observe whether the film agent delaminates or becomes moldy every 30 days.

[0090] Specifically, the storage stability of the fruit-protecting film agent for fruit without bagging, prepared in Example 3, was tested, combined with... Figure 3 As shown, Figure 3 In the diagram, a1 represents the membrane state before storage at room temperature (25℃), b1 represents the membrane state after 6 months of storage at room temperature; a2 represents the membrane state before storage at 40℃, and b2 represents the membrane state after 6 months of storage at 40℃.

[0091] Depend on Figure 3 It can be seen that the film agent remains uniformly transparent and shows no delamination or mold growth, regardless of storage conditions at room temperature or 40°C. This demonstrates that the fruit-protecting film agent for fruit without bagging, prepared according to the embodiments of this disclosure, exhibits excellent storage stability.

[0092] Therefore, compared with the prior art, the fruit-crack-resistant film agent for fruit without bagging in this disclosure includes a film-forming matrix, a crack-resistant agent, a surfactant, an antibacterial agent, and adjuvants. The raw materials are all agricultural-grade or food-grade inexpensive materials, which are easily affordable for ordinary growers. The crack-resistant agent is calcium-containing organic nanoparticles. After spraying, the calcium-containing organic nanoparticles can enter the fruit peel cells, strengthen the cell wall structure, and play a crack-resistant role. It also contains biostimulants, which are beneficial to promoting the accumulation of sugar and flavor substances in the fruit. The film layer formed after spraying is uniform and flexible, and the elongation at break of the film layer is more than 250%, which can stretch with the expansion of the fruit without breaking. The adjuvants can improve the flexibility of the film, enhance the stability of the film, and improve the anti-stratification ability of the film agent during storage. By adding antibacterial agents, the film agent can be stored at room temperature for 6 months and at 40°C for 3 months without mold growth. The film agent of this application is a single-agent spray, which avoids the need to control the interval of multiple agents in the prior art and is conducive to improving the efficiency of operation.

[0093] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0094] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An antihail bag-free fruit film agent for fruits, characterized by, By weight, it comprises the following components: 1-10 parts film-forming matrix, 0.3-3 parts anti-cracking agent, 0.1-0.6 parts surfactant, 0.2-2 parts antibacterial agent, 0.1-1 parts adjuvant, and 84-98 parts deionized water; wherein the anti-cracking agent is calcium-containing organic nanoparticles.

2. The bagless fruit cracking film agent for fruits according to claim 1, characterized by, The film-forming matrix is ​​selected from one or more combinations of polyacrylic acid, polyethylene oxide, polyvinyl alcohol, polymaleic anhydride, polyethylene glycol, polyacrylamide, polyvinylpyrrolidone, polyethylene oxide, sodium carboxymethyl cellulose, hydroxypropyl methylcellulose, methylcellulose, soluble starch, low-methoxyl pectin, polyvinyl acetate, or gelatin.

3. The bagless fruit cracking film agent for fruits as claimed in claim 1 wherein, The anti-cracking agent includes calcium-based anti-cracking components, biostimulants, and nutritional enhancers.

4. The fruit-crack-preventing film agent for fruit without bagging according to claim 1, characterized in that, The surfactant is selected from one or more combinations of Tween 80, alkyl glycosides, imidazoline amphoteric surfactants, dodecyl dimethyl betaine, and isomeric alcohol ethers.

5. The fruit-crack-preventing film agent for fruit without bagging according to claim 1, characterized in that, The antibacterial agent is selected from one or more combinations of chitosan, sodium benzoate, potassium sorbate, and hesperidin.

6. The fruit-crack-preventing film agent for fruit without bagging according to claim 1, characterized in that, The additive is selected from one of the following: vinylpyrrolidone-ethyl acetate block copolymer with 30% VA content, glycerol, or 25% glutaraldehyde aqueous solution.

7. The method for preparing the fruit-bagged, crack-resistant film agent for fruits according to claim 1, characterized in that, The particle size of the calcium-containing organic nanoparticles is 5~20nm.

8. A method for preparing a fruit-bagged, anti-cracking film agent for fruits as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1: Weigh the film-forming matrix and deionized water according to the ratio, add them to the container and mix, stirring until completely dissolved; let stand and cool to room temperature to obtain the basic solution; S2: Dissolve the biostimulant in deionized water to prepare solution A with a mass fraction of 0.1-5%; dissolve the nutrient-enhancing component in deionized water to prepare solution B with a mass fraction of 0.1-5%; dissolve the calcium-based anti-cracking component in deionized water to prepare solution C with a mass fraction of 5%; under stirring conditions, mix solution A and solution B at a mass ratio of 0.5-5:1 to obtain mixed solution one; then slowly add solution C to mixed solution one, stir continuously for 15 minutes, and let stand to obtain a calcium-containing organic nanoparticle suspension; S3: Under stirring conditions, add the calcium-containing organic nanoparticle suspension and antibacterial agent prepared in S2 to the base solution prepared in S1 according to the ratio until the solid is completely dissolved, let it stand to defoam, and obtain mixed solution two. S4: Add surfactant dropwise to the mixed solution 2 obtained in S3 according to the ratio, and then add the auxiliary agent. Mix the components evenly under stirring conditions to obtain a fruit-crack-preventing film agent for fruit without bagging.

9. The method for preparing the fruit-bagged, crack-resistant film agent for fruits according to claim 8, characterized in that, In S1, the temperature is controlled at 25~95℃ and the stirring speed is 100~800rpm.

10. A method of using the fruit-bagged, anti-cracking film agent for fruits as described in claim 1, characterized in that, Spraying should be carried out during the second stage of fruit expansion, ensuring the fruit surface is completely wetted until it begins to drip naturally, so that the fruit is evenly covered.

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